Neurodevelopmental disorders of childhood,
including language-related and learning disabilities, constitute a
large percentage of the childhood disorders seen by child clinical
neuropsychologists. Language impairments and learning disabilities
resulting from phonological core deficits are featured, as are
mathematics difficulties resulting from nonverbal, reasoning, and
perceptual deficits. Recently these disorders have often been
combined with the new term, learning and language impaired. A large
body of research has burgeoned over the past decade. There are some
children who simply exhibit a language delay as well as a few
children with a learning disability without a significant language
delay. For that reason we will discuss language disability somewhat
separate from learning disabilities although they are related and
should be viewed as such.
Each of these neurodevelopmental disorders will
be explored within a transactional model, where the genetic and
prenatal/postnatal history affecting neuropsychological, cognitive,
perceptual, and memory functions will be reviewed. The manner in
which family, school, and social factors interact with and
ultimately influence the manifestation of these disorders will also
be discussed. Research and clinical literature will be
incorporated, and implications for assessment and intervention will
be addressed.
Articulation Impairment
Articulation Impairment (AI) decreases with age
and is approximately 2:1 male to female in incidence (Petherham
& Enderby, 2001). In the
past, children with AI were considered to have primary motor system
problems, and therapies were devised to address motor learning
patterns. Recent conceptualizations suggest that linguistic
abilities, particularly phonological processing skills, play an
important role in AI. From this perspective, speech sound
production is viewed in light of global language functions,
including syntax, semantics, and pragmatics (Fox & Dodd,
2001).
Research has suggested that there are four types
of articulatory difficulty: articulation disorder, delay,
consistent use of atypical error patterns, and inconsistent
pronunciation (Dodd, 1995). These
subtypes have been found in German speaking populations (Fox &
Dodd, 2001) as well as Cantonese
children (Holm & Dodd, 2001).
Further study has found that, in a large sample of English-speaking
children referred for a speech evaluation, 57.5 percent had a
phonological delay, 20.6 percent had non-developmental errors, 9.4
percent made inconsistent errors on the same sound, and 12.5
percent had an articulation disorder (Broomfield & Dodd,
2004b). In this sample no child
had a significant hearing impairment, diagnosed learning
disability, or physical disability. Although attempts have been
made to determine whether children with articulation disorders also
have general language deficits, it is unclear whether AI should be
considered a linguistic (phonological disorder) or a neurogenic
(developmental motor apraxia) disorder.
Neuropsychological Correlates of AI
Children with AI are more similar to typically
developing children than to children with language disorders. There
are no specific neuropsychological correlates for children with a
sole diagnosis of AI. Children that were language impaired (LI) had
more trouble with speech perception capabilities, whereas children
with AI performed better than control children on these measures
(Snow, 2001). AI children
generally show fewer omissions, transpositions, and syllable
additions, compared to LI children.
In a multivariate analysis differentiating AI
from normal children, the following variables were predictive of
group membership: weight, temporal ordering of visual graphemes (e
and k), and identifying syllables hae/ compared to /dae/ (Stark
& Tallal, 1988). In a smaller
group of children with AI, weight, family history of speech
disorders, history of motor delays, difficulty identifying
syllables (/bad
/ due/), and problems discriminating
light flashes were significant in differentiating AI children from
normal controls. In this study, AI and LI children were all heavier
and taller than the control group. There are no clear-cut answers
as to why weight is associated with LI and AI, but speculations
suggest that heavy children may be more socially awkward,
particularly if they are also clumsy; that low self-esteem may be
manifested in less spontaneous speech, especially if accompanied by
poor expressive language skills, or that uneven or rapid growth
periods may place challenges on speech musculature (Stark &
Tallal, 1988).
While children with AI have difficulty
controlling involuntary movements of arms as well as with rapid
fine motor coordination tasks, they are able to produce CV
syllables in rapid succession when speaking (Leonard,
1998). Compared to LI groups,
children with articulation disorders did not show difficulty on
measures of verbal auditory processing or speech discrimination.
Further, children with AI who have mild expressive language
problems appear to function more similarly to typically developing
children than to LI groups. In general, very few children with
articulation disorders are found to show similar difficulties
compared to children with more serious language impairment (Tallal
& Fitch, 2005).
Language lmpairment
Language impairment and speech disorders are
considered to be communication disorders, and are often discussed
along with reading impairment (Tallal & Gaab, 2006). Language impairment is often difficult
to untangle from learning disabilities (or dyslexia) and studies
often include participants with both difficulties. While this
section will attempt to focus on language impairment, some of the
studies will have samples that have both disorders.
The incidence of pediatric speech and language
disorders is estimated to be approximately 33 percent of children
aged 5–12 years of age (Law, Boyle, Harris, Harkness, & Nye,
2000). The gender ratio has been
found to be approximately 3:1 for a language disorder and 2:1 for
an articulation disorder, with males more likely to be diagnosed
with either disorder than females (Broomfield & Dodd,
2004a). Of the children evaluated
in a large clinic in England 28 percent showed a mild disability,
39 percent a moderate disability, and 12 percent had a severe
disability (Broomfield & Dodd, 2004a). It was found that children with a severe
language disability showed problems with receptive language
disorders, a finding not present for those with articulation
disorders. Children who showed global language problems were more
impaired and at higher risk of later academic difficulties than
those with isolated difficulty (Johnson et al., 1999; Shriberg, Tomblin, & McSweeney,
1999).
The main risk factors that have been identified
for a language impairment include pre- and perinatal medical
problems, otolarynological problems, problems with early feeding
due to sucking difficulty, and family history (Johnson et al.,
1999). There also appears to be a
genetic predisposition to language impairment (Stromsvold,
2001) with monozygotic twins
showing a higher concordance rate than dizygotic twins. Most of the
studies reviewed on genetics have been from clinic-referred
samples. Studies that have used samples from the community have
found a modest genetic influence on low vocabulary skills at two
years of age (Price et al., 2000), and a stronger relation at older ages
(Eley, Dale, Bishop, Price, & Plomin, 2001; Spinath, Ronald, Harlaar, Price, &
Plomin, 2003).
Studies of large community-based twin samples
have found a relation between language performance and heritability
(Spinath, Price, Dale, & Plomin, 2004; Viding et al., 2004). Heritability was found to be greater for
children with more severe impairments than for those with mild
impairments. It was also found that genetic and environmental
influences appeared to be qualitatively and quantitatively similar
for boys and girls. Similar to earlier findings, language
impairment was present more often in boys than in girls.
Neuropsychological Correlates of LI
Fitch and Tallal (2003) indicate that impairment of spoken
language and the underlying neuropsychological mechanisms may be
the common thread between production and comprehension language
difficulties, reading problems, mathematics problems, written
language, and social difficulties in children with learning
disabilities. It has been hypothesized that language disorders are
a result of impaired temporal processing of auditory information
(Tallal, 2004).
Children with specific language impairment (LI)
or developmental dysphasia have been to found to have a number of
difficulties:
-
significant deficits in expressive and/or receptive language, with normal abilities in nonverbal areas;
-
deficits in speech perception and poor vocabulary skills, including naming, memory, syntax (grammar), and semantics (word meaning), and
-
impaired temporal sequence of nonverbal auditory stimuli and poor discrimination of sounds, particularly when auditory signals are presented rapidly (Semrud-Clikeman, 2006). Speech articulation, syntactic, and semantic deficits may also be present.
It is difficult to determine a causal link
between brain functions and language impairment in children.
However, several tentative hypotheses have been offered. One is
that atypical patterns of symmetry of the planum temporale are
associated with verbal comprehension problems, phonological
processing deficits, and expressive language difficulties (Foster,
Hynd, Morgan, & Hugdahl, 2002;
Morgan & Hynd, 1998). The
other assumes that perisylvian temporal cortical activation is
present for processing auditory speech stimuli . Both the right and
left hemisphere temporal regions appear activated, and each
hemisphere may have a different role to play in the analysis of
sounds (Binder et al., 2000). A
study using fMRI technology in adults with normal language
abilities suggests that the superior temporal lobes are involved in
the decoding of acoustic signals of speech, whereas the left
frontal lobes are involved in semantic operations (Eckert, Leonard,
Possing, & Binder, 2006).
Binder, Frost, Hammeke, Rao, and Prieto (1997) suggest that language processing is
probably hierarchical in nature, involving primary sensory levels
and intermodal association regions for higher cognitive activities.
As processing demands move from simple (unimodal) to complex
(multimodal), more brain regions are likely to be involved. Further
research into these mechanisms is underway and will undoubtedly
shed more light onto the neurological basis of language, and
further clarify the role of selective attention, memory, cognitive
associations, and semantic functions on language processes.
Other research indicates that children with LI
are less efficient on neuropsychological tasks involving rate of
motor performance (rapid alternating finger movements); dihaptic
stimulation (simultaneous perception of bilateral tactile
stimulation), and left-right discrimination (Talcott et al.,
2000). LI children also had less
control over involuntary movements than control children, and
although signs of involuntary movements are observed in both
groups, LI children have movements of longer duration.
Studies have indicated that children with LI
experience difficulties with working memory and short-term memory
(Adams & Gathercole, 2000;
Balthazar, 2003; Gathercole,
Tiffany, Briscoe, & Thorn, 2005; Montgomery, 2004). Phonological working memory and impaired
language ability are related (Marton & Schwartz, 2003; Norrelgen, Lacerda, & Forssberg,
2002). A link has also been found
between visual-spatial working memory and language development
(Marton & Schwartz, 2003).
A possible link between visual-spatial working
memory and language impairment has been found, but requires
additional study to fully understand how these difficulties
translate into language performance (Adams & Gathercole,
2000; Hoffman & Gillam,
2004). To investigate these
relations more closely, a large study of kindergarteners evaluated
the relation between working memory and language skills (van Daal,
Verhoeven, van Leeuwe, & van Balkom, 2008). Findings indicated
that phonological working memory was predictive of semantic and
syntactic abilities, while visual memory was weakly related to
speech production skills. It was hypothesized that phonological
working memory is related to maintaining lexical semantic
information while processing the verbal information. Baddeley’s
model of working memory (discussed in Chapter
6) was confirmed for language ability and
disability for the phonological loop and the central executive, but
not strongly for the visual sketch pad. These findings are
consistent with previous research showing a strong link between
phonological working memory and language ability (Alloway &
Gathercole, 2005). In conclusion,
working memory deficits particularly in phonological coding as well
as in lexical retrieval appear to be important for our
understanding of language impairment and likely interfere with
cognitive processing as well as learning.
Cognitive Processing Features of LI
Children with language impairments exhibit
problems with rate processing deficits; that is, children with LI
have auditory processing deficits or difficulty in processing
auditory signals that have short segments or are presented rapidly
in a series (Fitch & Tallal, 2003). Some suggest that this is the basic
deficit that underlies many of the neuropsychological and cognitive
features associated with LI (Tallal, 2004). Rate processing weaknesses have been
found in rapid speech production; finger identification (two
fingers); association of consonants and vowels (ba versus da);
processing of cross-modal, nonverbal stimuli, and simultaneous
tactile stimulation (face and hand). Auditory masking may explain
some of the auditory deficits found in LI children, where the rapid
presentation of signals runs on top of or masks other, later
occurring signals. Masking also may account for other problems
observed in both the tactile and motor areas, where a sequence of
stimuli or movements interferes with discrete single stimuli.
Tallal (2004)
concludes that there may be a common thread through interacting
neural substrates for both speech and nonverbal processing that
“incorporate rapidly changing temporal cues” that appear to be
deficient in children with LI (p. 183) (Tallal, 1988). Normal infants discriminate subtle
temporal signals (i.e., speech and nonverbal stimuli), that were
problematic for LI children 5–9 years of age. Research suggests
that children with LI are characterized by deficits in the ability
to perceive and to produce information in rapid time sequences.
This deficit is not specific to language, but includes other
processes (e.g., motor, tactile, memory). Stark and Tallal
(1988) hypothesize that “a basic
neural timing mechanism” interferes with the simultaneous
processing and production of information. While other higher level
linguistic deficits may also be present, the timing mechanism
deficit seems to have a significant negative impact on various
processing skills. Ways to alter the functioning of this “neural
timing mechanism” are explored in the discussion on intervention
implications.
Rate processing deficits appear in both children
with learning and language problems. Tallal and Gaab
(2006) have found that these rate
processing deficits and sensorimotor delays are consistently found
in children with language impairment. Infants with a family history
of learning and language problems take longer to learn how to
discriminate between two tones than those without such a history
(Benasich & Tallal, 2002). The
difficulty in learning how to discriminate between the tones was
strongly linked to later difficulties with language development
independent of the language being learned. Similarly, Foxton et al.
(2003) found that problems in the
ability to acquire phonological discrimination and speech
intonation knowledge were related to later difficulties in language
as well as in reading. Children with LI frequently develop later
reading problems, and as many as 50 percent of young children with
impaired language also show math difficulties and reading problems
in elementary school (Tallal, 2004). There have been links between language
impairment and reading and writing difficulties.
Social-Psychological Correlates of Ll
The psychosocial functioning of children with
language problems is often not investigated separately from that of
children with learning disabilities. In general, discussions of
social difficulties in children with learning disabilities have
focused on the communicative competency of children in social
situations, level of moral development, perspective taking and
empathy for others, understanding of nonverbal cues, and problem
solving abilities (Beitchman et al., 2001). Children with LI tend to have a higher
rate of emotional and behavioral disorders than would be expected,
with some finding that 80 percent of juvenile delinquents either
show a current language delay or have a history of language
impairment (Beitchman, Nair, Clegg, Ferguson, & Patel,
1986; Hall & Moats,
1999). Children with LI are at a
higher risk to develop emotional difficulties compared to typically
developing peers (Conti-Ramsden & Botting, 2008).
The extent to which social-emotional difficulties
are related to language impaired children without learning
disorders in general needs further exploration. It does seem
evident that communication and verbal intelligence are important
variables in determining social adjustment, in conjunction with
other cognitive and behavioral factors. If a child is unable to
express what he/she needs, then it is likely he/she will turn to a
more physical manner to express feelings or to turn those feelings
inward and not express them.
Implications for Assessment
There is a paucity of decent measures for
language impairments in both young and older children. It is
especially difficult to find one adequate test that measures
phonemic awareness, syntax, and semantic skills, and analyzing
subtests from more than one instrument presents psychometric
measurement problems (e.g., comparison of grade or age levels from
different tests with dissimilar reliability and validity
standards). Language pragmatics are also often overlooked, so it is
difficult to determine the effects of LI on communication in
general. Table 6.1 provides a list of commonly used measures for
assessing language. It is important to use parts of tests in order
to answer particular questions about the child’s functioning. For
this reason, the astute clinician will be aware of all these
measures and select the most appropriate ones for the child at
hand.
Implications for Interventions
Interventions for language disorders may be (1)
preventive, by reducing the probability of reading disorders; (2)
remedial, by addressing the language or communication deficits, or
(3) compensatory in nature (Stark, 1988). Early identification and intervention at
preschool age are crucial to increase the likelihood of preventing
the associated features of severe communication disorders. However,
most intervention research has focused on children with cognitive
delays or hearing impairments, a fact that complicates the picture
when evaluating the efficacy of such research when these disorders
are not also present.
Fast ForWord Language (FFW-L) (Scientific
Learning Corporation, 1998) is a popular intervention tool that has
been suggested to correct difficulties in temporal processing of
information thought to be related to learning and language
difficulties. Some have found gains of 1–1 ½ years following six
weeks of training (Merzenich et al., 1996; Tallal & Gaab, 2006). This program is based on Tallal’s theory
that language difficulties are due to problems with fast processing
of auditory information and that an intense intervention that
basically reprograms the brain to recognize sounds and blends will
improve language ability. FFW-L consists of two-stage
computer-generated lessons. In stage 1 of the training, speech was
temporally modified by lengthening the speech signal by 50 percent;
during stage 2, fast (3–30 Hz) transitional features of speech
were enhanced by as much as 20 db. The speech tracks were presented
on CD-ROMs. The speech sounds have a staccato quality, with
consonants (usually fast elements of speech sound) exaggerated
compared to vowels (typically slower speech sounds). Intervention
outcome may be best for children with expressive language problems
who do not have accompanying receptive language disorders
(Merzenich et al., 1996; Tallal
et al., 1996).
Independent researchers have also evaluated the
FFW-L program to determine its effectiveness with children who have
LLI (learning and language impairment). One study included a group
of 54 children with LLI assigned to one of three intervention
groups focusing on auditory training: FFW-L, Earobics, or the
Lindamood Phoneme Sequencing Program (LiPS) (Pokorni, Worthington,
& Jamison, 2004). All
children showed significant difficulties with language and reading
ability. Children were tested 4–6 weeks prior to the intervention
and 6–8 weeks after the intervention ended. Gains were not found on
retesting for any of the interventions.
Similarly, Cohen et al. (2005) compared Fast ForWord to commercially
available home programs and no programs in three groups of children
with severe mixed receptive and expressive language disabilities.
All groups received speech and language intervention services in
addition to these programs during the intervention period. At nine
weeks and six months after the intervention period all groups
showed significant improvement on standardized testing, but no
difference was found among the groups. Cohen et al. (2005) suggested that the groups did not provide
any additional support apart from the speech and language services
that were provided individually.
Gillam et al. (2008) studied 216 children aged 6–9 years in
four intervention programs: Fast ForWord Language, academic
enrichment, computer-assisted language intervention, or
individualized language intervention. Each child had treatment five
days per week for six weeks for one hour and 40 minutes each day.
All groups showed improvement on a standardized language test after
the intervention with no difference among the groups present. These
findings indicate that interventions that provide intensive
experiences with a great deal of feedback and support improve
language functioning. Gillam et al. (2008) concluded that the temporal processing
hypothesis of language impairment may not fully explain the
difficulties these children have and in and of itself, is not
sufficient for our understanding of language impairment. Thus,
auditory processing is likely a very important, albeit complex,
aspect to language development, and requires one to include many
aspects in understanding LI, not solely temporal processing of
stimuli (Johnston, 2006).
From the studies, it appears that auditory
processing deficits may result in both expressive and receptive
language deficits, while speech motor deficits may result in
expressive problems. Further, if auditory processing abilities are
intact, these abilities may facilitate the development of
expressive language and speech motor problems, while the opposite
does not appear to be the case. That is, intact speech motor
abilities have little impact on improving language problems
resulting from auditory processing deficits. The best treatment
approach is not always evident. As discussed briefly earlier,
learning and language disabilities go hand in hand, and many
children have both disorders. The following section discusses
learning disabilities from a neuropsychological point of
view.
Learning Disabilities
Children with learning disabilities (LD)
constitute the largest and fastest growing population of special
needs children in schools. Estimates place the incidence of
learning disabilities (LD) in general to be at 5–8 percent of
public school students (Semrud-Clikeman, Guy, Griffin, & Hynd,
2000). While there is a large
body of research indicating that learning disabilities are more
common in males than females with the incidence generally running
at 2:1 (Flannery, Liederman, Daly, & Schultz, 2000; Miles, Haslum, & Wheeler,
1999), others have found the
ratio between males and females to be relatively closer (Shaywitz
et al., 1995). The study that found equal distribution of males and
females, however, did find that when looking at the more severe
form of a reading disability, males were more affected compared to
females by at least 2:1.
Liederman, Kantrowitz, and Flannery
(2005) completed a comprehensive
review of the literature in male vulnerability for reading
disability. The findings from this review indicate that while the
literature does support a preponderance of males with reading
disabilities, more research is needed to evaluate the incidence
using more than one definition of LD, to compare genders based on
their own gender rather than across genders, and for researchers to
report effect sizes for their findings. Siegel and Smythe
(2005) suggest that the
discrepancy definition for LD (see below) may bias selection to
males. In addition, it has been found that early reading skills
(word identification, phonological processing) often differ between
the genders until fourth grade when the differences generally
disappear for most children (Share & Silva, 2003; Siegel & Smythe, 2005). More research is needed to examine male
and female differences based on the definition of a learning
disability, and possibly also evaluate differences in severity over
development. The definition of a learning disability continues to
be an area of contention and the issues are discussed in the next
section
Definitions
Currently, the field is replete with
controversies affecting how we think about, diagnose, and design
educational interventions for children identified as LD. Learning
problems can arise from divergent sources including genetic,
neuropsychological, cognitive/perceptual, social-psychological, and
environmental (i.e., home and school or classroom) factors. The
extent to which we can reliably identify which factors or
combination of factors affects a child's learning may be helpful in
distinguishing children with LD from other slow learners or
“garden-variety” poor readers. For example, we might expect to see
differences across variables depending on whether the learning
difficulties result from neurobiological, cognitive-perceptual,
intellectual, or instructional opportunities and experiences.
Learning disabilities have been defined in many
different ways over the years. Some have used the term “dyslexia”
to be synonymous with learning disabilities when, in fact, dyslexia
refers to problems solely with reading. The general term “learning
disabilities” refers to problems in any one of seven areas of
learning including listening comprehension, expressive language,
basic reading skills (word identification, phonological coding),
reading comprehension, written language, mathematics calculation,
or mathematics reasoning. Many assume that LD is due to a central
nervous system difference that contributes to the problems in
deciphering both written and oral language (Shaywitz,
2003).
Learning disabilities is a heterogeneous grouping
that generally includes children with difficulty learning despite
adequate ability and instruction in one of seven areas related to
language, reading, and mathematics. The definition generally
assumes a significant discrepancy between ability and achievement
that is often not well-defined. Differences in defining this
discrepancy has led to various incidences of LD across the country,
with some states defining the discrepancy conservatively (children
achieving below the second percentile for their age) and others
more liberally (a difference of 16 standard score points between
ability and achievement).
Many children may experience difficulties in more
than one area, and have difficulties with attention, emotional
adjustment, and/or behavioral problems as well (Lyon, Shaywitz,
& Shaywitz, 2003). The
majority of children identified with a learning disability have
difficulties in reading with many of these also experiencing
difficulties with written language. Poor phonological processing is
the most predictive of continuing reading difficulty (Shaywitz,
Mody, & Shaywitz, 2006).
When a severe learning disability is present,
even despite intensive remediation, achieving average reading
ability may be questionable (Lyon et al., 2003). It is likely that these children show
significant problems with emotional adjustment and with social
competence and, thus, academic interventions are complicated by
these concomitant difficulties. Comorbidity with other disorders is
present with learning disabilities similar to that with ADHD.
One theory for the mechanism that is faulty in
learning disabilities is the double-deficit hypothesis (Wolf &
Bowers, 1999). This theory
suggests that readers be grouped by their ability on measures of
phonological coding and automatized naming skills. There are three,
suggested subtypes: phonological deficit, naming speed deficit, and
phonological and naming speed deficit. The phonological deficit
subtype is those children that have difficulty with phonological
processing, but have average ability in naming. The naming speed
subtype has difficulty in automatized naming, but not in
phonological coding. When phonological coding and rapid naming are
both present, it is believed that the disorder is of a more severe
nature.
Research has supported the finding of naming
speed and phonological difficulties in children with learning
problems. A sole problem with naming speed, however, has not been
found in children with learning problems (Morris et al.,
1998). Other studies have found a
strong relation between phonological processing and reading
ability, and a weak or modest relationship between reading skills
and rapid naming ability (Hammill, Mather, Allen, & Roberts,
2002; Pennington,
Cardoso-Martins, Green, & Lefly, 2001). Rapid naming and phonological processing
also correlate with poorer phonological coding skills strongly
related to poorer automatized naming skills (Compton, DeFries,
& Olson, 2001; Schatschneider,
Carlson, Francis, Foorman, & Fletcher, 2002).
Comprehensive reviews of research on the
double-deficit hypothesis have found that phonological coding and
double-deficit subtypes do exist, but that the naming speed subtype
has not been confirmed and that naming speed and phonological
processing are strongly correlated skills (McCardle, Scarborough,
& Catts, 2001; Vukovic &
Siegel, 2006). This review also
found that phonological interventions improve rapid naming speed,
thus supporting the idea that these skills are not independent. The
review concludes that naming speed deficits are not characteristic
of a reading problem and are only important when they occur in
conjunction with phonological processing difficulty. Further
discussion of assessment and definition issues is presented below.
One of the areas that has challenged the research in learning
disabilities is the frequency of other disorders that co-occur with
a learning problem.
Diagnostic Issues
One of the major issues in the field of learning
disabilities is the precise definition of a learning disability and
who should be served under this category. Tied to this difficulty
is the problem of appropriately assessing a child to determine
whether a significant learning problem does exist. Previous
definitions have generally included an IQ-achievement discrepancy
that is called “significant,” but is not well-defined. As a result,
different states and, in some cases, school districts define
eligibility for services differently. Other definitions have
included the idea that the learning problem is due to a
developmental lag. These definitions will be reviewed in the
following section.
A meta-analysis of the relation between ability
and reading level was conducted to evaluate the use of the
IQ-Achievement discrepancy to define a learning disability (Fuchs,
Fuchs, Mathes, & Lipsey, 2000a, 2000b).
This meta-analysis found that children with the poorest reading
ability, compared to poor readers with lower ability levels, were
most appropriately served using the discrepancy model. Hoskyn and
Swanson (2000) also conducted a
meta-analysis looking at children with reading disability and those
with reading delays and lower ability. There was no differences
between the groups on reading and phonological processing, but the
brighter group performed stronger in vocabulary and syntax skills.
The difference between these two meta-analysis studies is likely
due to differences in sample selection for the studies as well as
the emphasis on an ability measure. The Fuchs et al.
(2000a, 2000b) study did not restrict the study to a
certain IQ level, while the Hoskyn and Swanson (2000) review included studies that utilized
significantly below average IQ samples. These differences in study
selection changed the findings and account for the findings’
discrepancies.
Steubing et al. (2002) conducted a further evaluation of the LD
literature with regard to the IQ-discrepancy issue. Their sample
included studies that used two groups to classify poor readers (IQ
discrepant and concordant), studies were not included that utilized
poor readers with significantly below average ability, and
additional domains such as behavioral functioning were included in
addition to cognition and achievement variables. In addition,
effect sizes were evaluated to determine whether the size estimates
were consistent across domains.
This analysis found few differences among the IQ
discrepant and IQ concordant groups on measures of phonological
awareness, rapid naming, verbal short-term memory, and vocabulary
ability. The IQ discrepant groups showed stronger effect sizes for
the Verbal IQ, Nonverbal IQ, and Full Scale IQ measures. Some
studies have shown that once decoding skills have been attained,
comprehension skills may be slightly better for children with
specific reading disabilities than for children with generalized
cognitive deficits (Stanovich, 2005). In addition, the IQ-discrepant group
scored better on measures of fine motor skills, concept formation,
spatial ability, planning skills, perceptual motor skills, and
nonverbal short-term memory. These measures were not believed to
affect reading skills, but are separate areas that would
discriminate the groups.
One of the issues that arises when IQ discrepancy
is utilized to diagnose a child with a learning disability is the
difficulty that children with lower ability have to qualify for
services. It is much more difficult for a child with an IQ of 85 to
qualify for services than a child with an IQ of 110, particularly
at a younger age. Some have questioned the discrepancy model’s use
and argue that it delays services to those children who need help
the most at an early age. This concern is particularly apt as
interventions have not been found to be as successful if started
after second grade, compared to early intervention (Lyon et al.,
2001; Torgesen et al.,
2001).
The difference between slow learners (those
children who do not read well, but read roughly commensurate with
their ability) and children with severe learning problems has been
evaluated to determine whether differences in reading skills are
present as well as response to intervention. Research on this issue
has yielded mixed results. LD and non-identified slow learners do
not differ in terms of demographics or psychoeducational test
scores, including both cognitive and affective measures (Strong,
Silver, & Perini, 2008).
Further, slow learners and LD groups show similar skills on
cognitive tasks related to reading (Lyon et al., 2001), including phonological awareness, and on
measures of reading achievement.
LD and garden-variety poor readers differ on
cognitive tasks not directly related to reading, such as nonverbal
reasoning skills and verbal-conceptual abilities which, in turn,
may ultimately affect intervention efficacy (Hulslander et al.,
2004). It has been suggested that
garden-variety poor readers have global deficits across a variety
of cognitive measures, whereas children with reading disabilities
have core deficits in the phonological area and, thus, have more
domain-specific deficits (Stanovich, Siegel, & Gottardo,
1997). Further, problems in
phonological awareness are shared by the two groups and serve as
causal factors for reading problems (Stanovich, 2005).
Developmental lag theories may be more
appropriate for children with mild reading problems than for
children with severe reading deficits or dyslexia (Chiappe,
Stringer, Siegel, & Stanovich, 2002). There is evidence that when children who
are delayed in reading are compared to children with the same
reading level, but who are younger than the children with reading
difficulties, the differences between the groups are smaller than
when the child is compared to same-aged peers (Stanovich, Siegel,
Gottardo, Chiappe, & Sidhu, 1997). Measures of vocabulary development,
pseudo-word decoding, phonological processing, verbal fluency, and
picture naming tasks are similar in children with the same reading
level. Differences are found in vocabulary level and metacognitive
ability with children who have reading difficulties scoring higher
(Goswami, 2006; Goswami &
Bryant, 1990).
Chiappe et al. (2002) studied adults and children with and
without reading disabilities to determine whether phonological
problems remained throughout the life span. The adults with LD
showed poorer performance compared to the typically performing
adults on measures of phonology. These difficulties were present
even when compared to same reading level children, particularly on
phonological processing and on naming tasks.
These findings lend preliminary support to the
developmental lag theory for children with mild reading problems.
The developmental lag theory is not as robust for severe reading
disabled and dyslexic groups. When matched to reading skills with
younger children, studies of children with specific reading
disabilities show mixed results. In a critical review of studies,
Stanovich, Nathan, and Vala-Rossa (1986) concluded that, “The presently available
evidence would appear to suggest the hypothesis that the
'garden-variety' poor reader is characterized by a developmental
lag; whereas the much rarer, dyslexic child displays a specific
phonological deficit, in conjunction with compensatory use of other
skills and knowledge sources” (p. 280). Further, although mildly
reading-impaired children should not be overlooked in our schools,
they may be expected to progress in reading when given
instructional resources and will eventually develop reading
abilities similar to their other cognitive skills. The same may not
be the case for the more severe and specific reading problems found
in children with LD.
Best practice now suggests that the technique,
Response to Intervention (RTI), is most appropriate for initial
work with children with reading problems before these children are
identified as having a learning disability. This technique is
generally thought to be most appropriate in the initial stages of
treatment when it is not clear how the child will respond to
treatment. As discussed above many children will respond to
treatment, both those with a mild learning disability and those who
are considered slower learners. These children benefit from
interventions that are designed prior to identification, and an IQ
discrepancy is not required to provide such support
(Semrud-Clikeman, 2006).
RTI generally consists of three tiers for
intervention. Often the first tier provides additional training for
teachers in teaching reading. Tier 2 is small group reading
instruction which is provided three times per week, and tier 3 is
either individual or two group members who meet daily (O'Connor,
Harty, & Fulmer, 2005). The
tier system improves reading skills in children in early school
grades (Vaughn, Linan-Thompson, & Hickman, 2003). There is limited support for RTI for
older students, particularly in high school (Kavale, 2005). While the new IDEA re-authorization
suggests using empirically validated interventions when working
with children with RD, RTI interventions have small to moderate
effects, suggesting only modest validation. In addition, these
interventions are generally for phonological processing and
phonemic awareness only, thus limiting their applicability to all
aspects of reading (Scruggs & Mastropieri, 2002; Strauss, 2001). Further work is needed and, based on
concerns that RTI may delay support for children with severe RD,
the technique should be evaluated for different levels of
disability. It is helpful to attempt interventions before a RD or
LD diagnosis is made, and RTI can be very helpful to that end.
Concern has been expressed that the technique has not been
empirically validated beyond the early grades and that it
identifies both too many false positives and false negatives to be
used as a sole manner for diagnosing RD/LD (Kavale, 2005).
Comorbid Disorders
When a reading disability is coupled with other
learning problems, a more severe form of the disorder is likely
present (Semrud-Clikeman, 2007).
Most children with a language-based learning disability have
difficulty with reading as well as with written language (Lyon,
1996b). Difficulties in written
language frequently involve problems with spelling, organization of
ideas, planning of the writing process, and ability to utilize
appropriate punctuation and grammar (Harder, Semrud-Clikeman, &
Maegden, 2006).
Many children who experience difficulty in
reading also have problems in mathematics. Approximately 6 percent
of children have a learning disability in mathematics
(Semrud-Clikeman, 2006). Most
often children with reading disabilities also show difficulty with
mathematics calculation while those with reading comprehension
problems also struggle with mathematics reasoning. Very few
children are diagnosed with a sole disability in mathematics.
Problems with visual-spatial and visual-motor skills are linked to
problems with nonverbal learning disabilities and are discussed
later in this chapter.
Approximately 35 percent to 75 percent of
children with learning disabilities also have significant problems
with attention (Semrud-Clikeman et al., 1992; Spencer, Biederman, & Mick,
2007). It is likely that
attentional and impulse difficulties make it problematic for the
child to attend to classroom instruction particularly on tasks that
are already very difficult for the child. In addition those
children with an ADHD diagnosis have a higher risk of having
problems with phonological processing, compared to those in the
general population (Lyon, 1996a).
Children who have ADHD (particularly with the predominately
inattentive subtype) and LD show more difficulty with their peers
in social desirability as well as significant signs of social
anxiety and low self-esteem (Kellner, Houghton, & Graham,
2003). In contrast, children who
were diagnosed with ADHD Combined subtype and LD showed problems
with externalizing behaviors and with social functioning due to
impulse control and hyperactive behaviors. In addition, children
with ADHD: Combined subtype also become more resistant to
interventions and require more intensive support due to significant
behavioral difficulties (Teeter, 1998).
Children with LD also are more susceptible to
emotional difficulties (Martinez & Semrud-Clikeman,
2004), and are more likely to
show internalizing disorders such as anxiety and depression as well
as withdrawal and low self-esteem. These problems may stem from
frustration with the learning process as well as lower expectations
for employment and financial success (Lyon, 1996b). Difficulties in emotional adjustment
have been found to extend into adulthood and to require ongoing
treatment through psychotherapy for low self-esteem and social
difficulties (Brieger & Majovski, 2008; Gregg, Coleman, Lindstrom, & Lee,
2007).
Genetic Factors
The search for the genetic basis of reading
disabilities has been helpful in determining the relationship
between environmental and genetic factors. The Colorado Reading
Project (Decker & Vandenberg, 1985; DeFries, Fulker, & LaBuda,
1987), one of the largest studies
of its type, found a strong relationship between reading
disabilities in identical or monozygotic twins (MZ) and in same-sex
fraternal or dyzgotic twins (DZ). The concordance rate was 71
percent for MZ twins and 49 percent for DZ twins, confirming a
strong genetic basis for reading disabilities in children. When the
proportion of variance accounted for by both genetic and
environmental factors was measured, the genetic factors were found
to be more important than environmental factors for explaining
differences in reading between MZ and DZ twins (DeFries &
Alarcon, 1996; DeFries et al.,
1997).
When gender differences and severity issues were
evaluated using a sample of MZ and DZ twins, heritability and
shared environmental influences were not found to differ between
the genders (Hawke, Wadsworth, Olson, & DeFries, 2007; Wadsworth & DeFries, 2005). Other researchers have found that the
heritability of LD in more severe populations was greater for males
than females (Harlaar, Spinath, Dale, & Plomin, 2005). One of the differences was the
definition of severity. When a more severe cutoff was utilized (the
most severe 5%, rather than 10%) a male gender bias was found
(Harlaar et al., 2005).
Differences may also be due to the various methodologies and
instruments used to measure reading skill. Harlaar et al.
(2005) administered timed tests
over the phone while Hawke et al. (2007) administered non-timed measures
in-person. In addition, the earlier study used younger children
while the other study used older children (Hawke et al.,
2007). These finding indicate
that further study that controls for the age and type of measure
used is needed to determine whether there is a genetic link to
severity and gender in LD.
Continuing study in the Colorado longitudinal
twin study has followed 124 twins with a history of reading
difficulty, and 154 twins with no history of learning problems over
5–6 years. Initial findings of significant learning problems were
present at the follow-up testing 5–6 years later. The most stable
measure was the reading measure with a stability correlation of
0.80. In addition the shared genetic influences accounted for 86
percent of the phenotypic relations for the twins with reading
problems, and 49 percent for the twins without reading problems
(Wadsworth, DeFries, Olson, & Willcutt, 2007).
Some studies have also evaluated the shared
environment variable for families with twins. Emerging evidence is
present that shared environment effects may be important during the
early years of development and schooling, particularly for phonemic
awareness and letter identification (Byrne et al., 2002; Harlaar et al., 2005; Petrill, Deater-Deckard, Thompson, &
DeThorne, 2006). Variables that
have been found to be important in the shared environment and
reading outcome include parental education and cognitive ability
(Christian, Morrison, & Bryant, 1998), and the family environment for promoting
reading and parental involvement in schoolwork (Foy & Mann,
2003; Petrill, Deater-Deckard,
Schatschneider, & Davis, 2005; Senechal & LeFevure, 2002). A further study of shared environment
with adoptive parents of twins was conducted to determine effects
that are separate from genetics. This study found that the adoptive
parents’ skills in pseudo-word decoding and phonological awareness
were related to the child’s reading skills, but only for the
youngest readers (Petrill, Deater-Deckard, Schatschneider, &
Davis, 2007). It was also found
that these shared environmental influences decrease with
adolescence to the point of almost zero.
In addition to a strong genetic influence for
reading ability and the contribution of shared environments for
younger children, there have also been studies evaluating the
various aspects of reading and heritability of those skills. Word
reading and reading comprehension are highly correlated in the
early grades, but this correlation decreases with mid-elementary
school years when reading comprehension becomes paramount for
success in school (Catts, Hogan, & Adlof, 2005; Scarborough, 2005).
Orthographic aspects of reading have also been
studied to determine the behavioral genetic contribution to these
skills. Orthographic processing is the ability to recall the
spelling pattern of a word that is retrieved from memory without
decoding the word (Ehri, 2005).
Adept readers can use rapid and automatized retrieval of words
particularly those with irregular spellings or pronunciations
(prevalent is not pre’ valent) (Byrne et al., 2008). Previous studies have found a genetic
correlation between phonological awareness and print knowledge
(Samuelsson et al., 2007),
combined word and nonword identification and spelling, rapid
naming, and reading comprehension (Byrne et al., 2007) and language ability (Bishop, Adams, &
Norbury, 2006).
Byrne et al. (2008) evaluated the contribution of genetics to
orthographic processing as well as skills such as nonverbal
reasoning. Twin pairs (225 MZ and 214 DZ) in the second grade were
compared on measures of orthography as well as the Block Design and
vocabulary tests from the WPPSI-R. Heritability for orthography was
found to be significant, but not shared environment variables.
Further analysis found that there is a shared genetic influence
between orthography and phonological coding. In addition it was
found that while there was some genetic overlap between overall
ability and reading skill, reading variables were substantially
separate from IQ.
Reading comprehension difficulty exists
separately from word reading accuracy (Oakhill, Cain, & Bryant,
2003). Further studies have found
that these children experience problems outside of phonological and
orthographic (word form) deficits, thus suggesting that reading
comprehension and these skills are dissociable (Perfetti, Landi,
& Oakhill, 2005; Scarborough,
2005). In addition, these
children also experience listening comprehension difficulties, both
with and without coexisting problems with phonological working
memory (Catts et al., 2005; Kovas,
Oliver, Dale, Bishop, & Plomin, 2005; Nation & Norbury, 2005).
Keenan, Betjemann, Wadsworth, DeFries, and Olson
(2006) sought to evaluate the
genetic involvement in word recognition, listening comprehension,
and reading comprehension. The second part of the study also
evaluated the relation between IQ and these reading skills in view
of genetic and shared environment contributions. Seventy
monozygotic twin pairs, 61 same-sex fraternal twin pairs, and 60
opposite-sex fraternal twin pairs were compared on measures of
reading and listening comprehension. Word recognition was found to
have a strong genetic influence and was strongly related to reading
comprehension and less strongly to listening comprehension. Reading
comprehension and listening comprehension were also found to be
related in the genetic analysis apart from the relation with word
reading. Environmental aspects were equally related to all the
reading aspects and not significantly related to genetic
influences. IQ was significantly heritable with the genetic path;
IQ to listening comprehension was stronger than listening
comprehension to word reading. Word recognition had a significant
genetic influence after IQ was controlled, which was also true for
reading comprehension. In all cases shared environmental influences
were not found to be significant for any variable. The authors
suggest that lower power may have influenced these findings.
The finding of a relation between IQ,
heritability, and reading disability was also evaluated by
Wadsworth, Olson, Pennington, & DeFries (2000). This study found that the genetic
influences of IQ were a more important cause of reading disability
for higher skills, and the environment had less of an impact for
those children with higher ability. Conversely, the children with
lower ability showed less genetic influences of IQ and more
influence from shared environment. These findings suggest that
children with lower abilities may require alternative, earlier
intervention. Response to intervention in this group has been very
successful (MacMillan, Gresham, & Bocian, 1998).
Prenatal/Postnatal Factors
To date, prenatal factors affecting a child's
capacity to develop phonological awareness deficits are virtually
unknown; however, there are several environmental factors that have
been found to be related to general language deficits and reading
disabilities. Although a biogenetic foundation for language is
virtually indisputable, postnatal factors associated with language
development typically emphasize the influence of environmental
stimulation. Infants 1–4 months of age are quite adept at
discriminating speech sounds, and can make discriminations between
ba and ga, ma and na, and preschool children seem to utilize
phonetic representations when processing language in short-term
memory (Molfese, Molfese, & Molfese, 2007; Molfese, Molfese, & Pratt,
2007). Studies with newborn
infants have found that children at this age may be aware of and
able to discriminate phonemes, even though they may not be aware
that phoneme units exist (Cheour et al., 2002). It is likely that experience plays a role
in the child's development of speech perception and vocabulary,
both of which are related to language acquisition and reading;
however, the role of the environment on these factors has not been
adequately investigated for poor readers. A predictable growth
spurt in phonemic awareness occurs in children at about the age of
six years, which appears related to efforts in teaching children to
read (Guttorm et al., 2005). The
genetic studies suggest that while experience plays a prominent
role in the development of phonemic awareness, children with
phonological deficits appear to have some biogenetic factor that
limits their ability to profit from exposure (Petrill et al.,
2006).
Prematurity is another prenatal factor that has
been evaluated in children with learning disabilities. Preterm
infants who were also of low birth weight have different responses
to auditory information and detection (Therien, Worwa, Mattia,
& deRegnier, 2004). These
differences have been tied to problems with recognition memory and,
later, reading disabilities (Curtis, Lindeke, Georgieff, &
Nelson, 2002; Rose, Feldman, &
Jankowski, 2002). It has also
found that these neural circuits can discriminate between term and
preterm infants and may be reversed with appropriate interventions
(Peterson et al., 2002).
Frequent ear infections may possibly relate to
later difficulties with auditory comprehension and phonological
coding. Children with frequent middle ear infections do not show
long-term language impairment, but do show a more pronounced right
ear advantage compared to children without such a history
(Asbjornsen et al., 2000;
Asbjornsen et al., 2005; Winskel,
2006). It was suggested by these
authors that early hearing difficulties relate to differences in
how auditory stimuli are processed and that the increased right ear
advantage seen in children with early and frequent ear infections
relates to compensation for problems with hearing. Further study is
needed to more fully understand these mechanisms.
Neuroanatomical Variations and Neuropsychological Correlates
Brain imaging has increased our knowledge of
neuroanatomical and neurofunctional contributions to learning and
learning disabilities. Early studies found differences in the area
of the planum temporale, a structure implicated in phonological
processing (Hynd, Semrud-Clikeman, Lorys, Novey, & Eliopulos,
1990; Morgan & Hynd,
1998). The planum temporale in
the left hemisphere is consistently larger in a majority of adults
(Galaburda, 2005; Geschwind &
Galaburda, 1985; Steinmetz et
al., 1992) and in fetuses,
newborns, and infants (Chi, Dooling, & Gilles, 1977). The left planum temporale is thought to
be the primary site for linguistic processes and reading (Morgan
& Hynd, 1998) because of its
proximity to the auditory association region and Wernicke's area.
The expected leftward asymmetry is rare in dyslexics, whereas
symmetry in the temporal regions is more frequent (Hynd &
Semrud-Clikeman, 1989; Kibby et
al., 2004; Shaywitz et al.,
2006). A number of studies report
that the symmetrical patterns appear to be the result of larger
plana in the right hemisphere (Galaburda, Sherman, Rosen, Aboitiz,
& Geschwind, 1985; Larsen,
Hoien, Lundberg, & Odegaard, 1990). Although others found smaller left
plana, different measurement techniques may be responsible for
these divergent findings.
Children with reading disabilities have
symmetrical or reversed asymmetry (R > L) in parietooccipital
regions, which is found less frequently in normal groups (Helenius,
Tarkiainen, Cornelissen, Hansen, & Salmelin, 1999; Tarkiainen, Helenius, Hansen,
Cornelissen, & Salmelin, 1999). This region of the brain, called the
occipitotemporal system, is involved in rapid recognition of words
and has been implicated in the orthographic route to reading and
spelling (Pugh, Mencl, Jenner, Lee et al., 2001; Shaywitz,
1998). In addition, in the
parietal, occipital, and temporal association areas including the
angular gyrus (also called the temporoparietal system) are areas
that are activated in reading of pseudo-words and phonological
processing (Pugh, Mencl, Jenner, Katz et al., 2001). This region is
important to translate unfamiliar words by using phonics and
step-by-step decoding.
The final area responsible for reading is in the
frontal regions of the brain. In children without reading
difficulty, this region is well connected to the posterior region
by the superior longitudinal fasciulus (see Chapter
2). This system connects the areas of the brain
responsible for oral reading in the frontal area to those
responsible for reading understanding in the temporal lobe of the
brain. It is believed that this system is important to prepare for
oral word reading and is related to phonological processing (Pugh,
Mencl, Jenner, Lee et al., 2001).
As the child develops these systems also develop
interdependently. When first learning to read the posterior regions
of the brain responsible for orthographic and phonological coding
are activated and allow the child to decode and analyze the word.
Once the word has become automatized (that is overlearned), a
neural trace is formed and the pronunciation, spelling, meaning,
and the way the word looks are all stored in long-term memory
within the written lexicon for that child. When the word is then
encountered the reading of the word is automatized and fast and the
posterior regions of the brain in the occipitotemporal regions are
able to fluently read the word quickly (Shaywitz et al.,
2006).
Children without reading disabilities develop
these systems simultaneously and are able to store words in memory
both phonologically and orthographically (Pugh, Mencl, Jenner, Katz
et al., 2001). As the child becomes more adept in reading the
occiptotemporal region shows increased activation, allowing for
smooth access to the word lexicon (Shaywitz, 2003). Children with learning disabilities
experience a disconnection between these systems, making word
reading labored and effortful. Functional imaging has found that
children with dyslexia show hyperactivation in the frontal system
(associated with naming and oral reading) which may be related to
trying to compensate for hypoactivity with phonological processing
subserved by the posterior systems (Fiez, 1997; Milne, Syngeniotis, Jackson, &
Corballis, 2002).
Hoeft et al. (2007) sought to evaluate the hypoactivation in
the left posterior systems and the left frontal hyperactivation in
a group of adolescents with dyslexia. There were four groups: two
groups with a diagnosis of dyslexia, one control group matched on
age to one of the dyslexic groups, and one control group matched on
reading level to the other dyslexic group. Relative to the
age-matched group, the dyslexic group showed hypoactivation in the
left parietal regions and hyperactivation in the left inferior
regions as well as in the caudate and thalamus. When compared to
the reading matched group, the dyslexic group showed hypoactivation
in the left parietal regions, but similar activation in the frontal
regions. The dyslexic group also had reduced gray matter volume
compared to both control groups. These researchers concluded that
the hyperactivation was a result of an attempt to compensate for
the reading problems. The hypoactivation regions were believed to
be a true brain abnormality that is associated with reading
disabilities and problems with learning to read (Hoeft et al.,
2006). To support this view,
findings from intervention studies have indicated that increased
activation in these regions occurs after intense intervention, thus
suggesting that these regions are a core deficit for dyslexia
(Aylward et al., 2003; Shaywitz et
al., 2004; Simos et al.,
2002).
Structural Differences
Differences have been found that discriminate
between children with and without learning disabilities at the
molecular as well as the structural level. Autopsied brains show
misplaced and misaligned cells particularly in the regions of the
perisylvian area, the left frontal region, and the language areas
(Galaburda et al., 1985;
Grigorenko, 2001; Humphreys,
Kaufman, & Galaburda, 1990).
Structural differences have been found in the planum temporale
(Duara et al., 1991; Hynd et al.,
1990; Rumsey et al.,
1986), the corpus callosum (Duara
et al., 1991; Fine,
Semrud-Clikeman, Keith, Stapleton, & Hynd, 2006; Hynd et al., 1991; Larsen, Hoeien, & Oedegaard,
1992), and the frontal lobe area
(Semrud-Clikeman, Hynd, Novey, & Eliopulos, 1991).
Semrud-Clikeman et al. (1991) found that atypical patterns of symmetry
in the planum temporale were related to word attack skills, passage
comprehension skills, and rapid naming abilities. Thus, the left
planum was postulated as a central language processing center.
Researchers have also explored other neuropsychological postulates
and have focused on deficient or abnormal patterns of hemispheric
lateralization related to attentional activation processes as
plausible explanations for the academic deficiencies exhibited by
children with LD.
Dichotic listening has also been utilized to
evaluate children with reading disabilities and hemispheric
specialization for auditory processing. Findings have indicated
that typically developing children show greater ease in focusing
attention when provided with a verbal cue while children with LD do
better when a tone cue is presented (Obrzut, Boliek, &
Asbjornsen, 2006). Other studies
have found that the usual right ear advantage for language is not
present on a dichotic listening task in children with LD (Helland,
Asbjornsen, Hushovd, & Hugdahl, 2007). Since there was no cue to trigger
attention to the task, children with LD showed less right ear
advantage and in some cases heightened left ear advantage due to
activating both hemispheres in order to solve the problem. Thus,
the child with LD is dividing attention between both ears and is
not as efficient as the child without LD.
Therefore, neither ear is as good as when
attention is direct and auditory processing is efficiently managed.
These difficulties are related to poorer verbal processing of
auditory information, an area of significant difficulty for
children with a reading problem (Lamm & Epstein, 1997). These findings are consistent with
functional neuroimaging studies that have also found lower
activation when processing oral information in children with LD
(Heiervang, Stevenson, & Hugdahl, 2002; Helenius et al., 1999; Hugdahl et al., 2003)
These studies raise questions about whether
children with learning disabilities have attentional imbalances
between the two hemispheres or whether there are problems in
interconnected attentional systems. Further research is necessary
to determine the relationship between morphology and attention
control mechanisms during language tasks in children with LD.
Padlonsky (2008) found that
children with ADHD and LD who had a history of otitis media showed
a more severe form of disability characterized by deficits in
phonological processing. The extent to which these
neuropsychological aspects are further related to the cognitive,
academic, and perceptional deficits associated with LD also needs
further exploration.
Implications for Assessment
The difficulties that are present with a
definition of a learning disability have not been resolved at this
point in time. Ongoing research, however, has evaluated the
different problematic areas in learning disabilities to attempt not
only to understand the problems posed for the child in learning to
read and write, but also to design interventions that are helpful
to the child.
Reading Disabilities: Phonological Core Deficits
Phonological awareness deficits are a primary
cause of reading deficits (Shaywitz et al., 2006). As described earlier in this chapter,
children with phonological reading disabilities (PRD) experience
trouble in early reading and also have associated difficulties in
speech perception, speech production, and naming tasks.
Phonological awareness is the ability to use the phonemic segments
of speech, including the awareness and use of the sound structure
of language. Related difficulties in phonological processing
include difficulty understanding how sounds relate to one another
(phonemic awareness deficits), problems with auditory
discrimination, naming and vocabulary deficits, and problems with
working memory for sounds and sound combinations. Reading requires
learning the relationship between graphemes (written letters) and
phonemes (sound segments). Thus, children with phonological
deficits have difficulty applying the alphabetic principle when
reading unfamiliar words (Torgesen et al., 2001). Table 12.1 summarizes selected research findings.
Table
12.1
Summary of specific deficits associated
with reading disabilities: Phonological Core Deficits (PRD)
Biogenetic
Factors
– 40% variance in word recognition is
genetic
– h2g = .62 phonology/reading
deficits
– h2g = .22 orthographic/reading
deficits
|
Environmental Factors: Prenatal and
Postnatal
– Orthographic deficits related to exposure
to print and learning opportunities
– Development of speech and vocabulary
related to language acquisition and reading
– Growth spurt in phonemic awareness at 6
years related to reading efforts
– Despite strong heritability of
phonological awareness, deficits can be modified
|
||
Temperament
– No known correlates
|
Birth
Complications
– No known correlates
|
||
CNS
Factors
– Gray matter dysfunction
– Left temporal anomalies
– Larger plana in right hemisphere
– Symmetrical R/La temporal
lobes
– Symmetrical or reversed parieto-occipital
regions
– Abnormal asymmetry (R > L) in
prefrontal regions
– Abnormal asymmetry in parietal
regions
|
|||
Neuropsychological Factors
– Rapid naming
– Abnormal hemispheric lateralization
– Attention activation of RH interferes
with LH verbal processing
– Attentional control mechanisms between
hemispheres
– Phonemic hearing, segmenting, and
blending
|
|||
Intellectual
– Verbal weaknesses
– Vocabulary knowledge
– Verbal associations
– Word similarities
– Verbal fluency
– Receptive language
– Expressive language
– Verbal IQ
– Comprehension
|
Perceptual
– Phonemic
– Speech
|
Memory
– Digit span
– Speech sounds
– Word series
– Letter strings
– Phonetic strategies
|
Attentional
– Strong comorbidity of reading problems
and ADHD
– Attention to phonemes
|
Academic/Behavioral
– Motivational problems
– Chronic reading problems
– Disengaged in learning
– Spends less time reading
– Reading and spelling
|
Psychosocial
– Research is sparse
– RD in general show internalized disorders
(e.g., depression)
|
Family
– Research is sparse on PRD
– Prenatal and postnatal risk factors
related to general learning and behavioral problems
– “Disorganized” and/or poverty,
environment more important with age
|
Guidelines for classifying and treating LD may be
more clearly articulated and systematically investigated within
this transactional framework. Although not every child is expected
to demonstrate all of the associated features presented, Table
12.1 suggests
an interaction among the neuropsychological, cognitive, academic,
and psychosocial problems that may accompany reading disabilities
resulting from phonological core deficits.
Intellectual, Perceptual, Memory, and Attentional Functions
Intellectual Functions
Children with phonological core deficits evidence
weaknesses on a variety of verbal measures, including vocabulary
knowledge (Berninger, Abbott, Abbott, Graham, & Richards,
2002); auditory memory and verbal
associations (Shaywitz et al., 2006); receptive vocabulary, word similarities,
and verbal fluency (Fletcher, Morris, & Lyon, 2003), and receptive and expressive language
(Wills, 2007). Measures of
intelligence relate to the child’s exposure and experience with
language, a skill that is often compromised in children with a
learning disability (Siegel & Smythe, 2005). Stanovich (2005) refers to the Matthew effect to describe
the reading-IQ relationship, where reading has “reciprocal
causation effects” on other cognitive skills. Children with reading
deficits read less, acquire less general and specific knowledge,
and may fall further and further behind in achievement and verbal
skills (Wong, Strickland, Fletcher-Janzen, Ardila, & Reynolds,
2000).
Perceptual Functions
Difficulty in phonemic processing underlies
reading deficits in many children. The child's ability to perceive
spoken words appears related to reading difficulties and is less
than accurate, particularly under adverse or noisy conditions
(Riccio, Cohen, Garrison, & Smith, 2005). Deficient speech perception seems
evident, but children with phoneme awareness deficits may also have
poor memory for speech sounds as well. (Tunmer, Chapman, &
Prochnow, 2003).
Memory Functions
Research does provide evidence that children with
reading disabilities do poorly on a variety of memory functions,
including deficits on digit span, recall of letter strings,
nonsense words, and word order (Jarrold, Baddeley, Hewes, Leeke,
& Phillips, 2004). The
ability to remember a series of words precedes a reading disability
diagnosis and appears to be a risk factor rather than a consequence
for reading problems (Adams & Gathercole, 2000). Poor readers are unable to use the
phonological structure of language to hold letter strings in
short-term memory (Riccio, Garland, & Cohen, 2007). Some have suggested that poor readers
rely on word meaning in an effort to remember words, and do not
appear to use visual rather than phonetic memory strategies. To
support this hypothesis, error pattern analysis suggests that poor
readers make errors that are consistent with phonological
processing and in a manner similar to good readers, but that their
error scores are quite high (Mann, 2003). These findings indicate that they are
not using good orthographic coding to recall the spelling and word
form in order to read a problematic word.
Academic and School Adjustment
Early reading failure has been shown to create
motivational problems in children. Children with chronic reading
problems often dislike going to school, and develop secondary
self-esteem problems (Martinez & Semrud-Clikeman,
2004). Wills (2007) further reports that remedial classes
often drill in phonics or word recognition, but may deemphasize
passage comprehension so that the child spends less time reading.
Eventually the child develops more generalized cognitive deficits
involving numerous subject areas due to delays in reading
skills.
Social-Psychological Adjustment
Research addressing the socioemotional
functioning of children with phonological core deficits is sparse.
Other research shows that children with LD who demonstrate
distinctively lower verbal abilities with intact visual-spatial
skills were rated by their parents as having more internalizing
disorders, particularly depression (Bender, Rosenkrans, &
Crane, 1999). The extent to which
this applies specifically to children with phonological core
deficits is yet to be established. In addition, it appears that
children with basic phonological processing disorders are prone to
develop psychosocial disturbances if parents and teachers have
unrealistic expectations or if acting out serves as a mechanism for
avoiding school and/or schoolwork. Others have found that children
with conduct disorders (CD) also have lower verbal intelligence
(Grigorenko, 2006). The extent to
which CD and language-based difficulties are associated with poor
achievement and learning problems needs further study (Sundheim
& Voeller, 2004). Children
with neurological signs who also have learning disabilities have
been found to be at higher risk for emotional disturbance
(Glassberg, Hooper, & Mattison, 1999)
Family and Home Factors
There are few studies addressing family home
factors and reading disabilities, specifically for children who
display phonological awareness deficits. The research that has been
conducted generally shows genetic linkage to be stronger than
environmental variables (Petrill et al., 2006). Studies investigating family and home
influences on learning disabilities in general have found that
prenatal and postnatal conditions are highly related to risk
factors, including the development of general behavioral or
learning problems during the first 20 months of life (Pennington,
2006). Further, risk conditions
were found in families that were characterized as disorganized
and/or in poverty, and these environmental factors became more
significant as the children became older. Children who continued to
demonstrate moderate to severe problems tended to come from
families with low economic status and with a high degree of
disruption and psychopathology in the family. Socioeconomic status,
home conditions, and educational attainment of family members may
act as compensatory variables for children initially identified as
at risk for reading problems, but who later show normal achievement
progress (Capozzi et al., 2008).
It is premature to generalize conclusions reported in studies
investigating children with general learning problems to students
with phonological core deficits. However, stable and consistent
home situations, strong emotional family bonds, and child
characteristics (e.g., easy temperament) appear to be important
factors associated with the “resilient” child who appears less
susceptible to the adverse effects of risk factors (Elksnin et al.,
2001).
Implications for Intervention
Evidence indicates that phonologically impaired
children show normal progress in math, but continue to show severe
delays in reading despite remedial attempts in school (Torgesen,
2004). When remedial techniques
specifically address phonological core deficits, the outcome is
more positive for at-risk students and children with PRD. Studies
have also shown increased reading abilities when phonological
awareness is combined with metacognitive techniques (Cunningham,
2007), and when phoneme awareness
is contextualized within the reading curriculum (Cunningham,
2005).
Early identification and remediation have been
offered in order to provide the children with early support who may
be at risk for reading difficulties (National Reading Panel, 2000).
Early remediation has also been suggested to help prevent the
Matthew effect which is related to poorer readers reading less than
good readers, thus widening the gap between the two groups
(Torgesen, 2004). Specific
training in phonemic awareness for young children in kindergarten
and early elementary grades has proved successful and seems
preferable to control conditions where children are not exposed to
these skills (Bishop & Snowling, 2004). Further, children as young as two years
of age are at extreme risk for severe reading problems when they
have a family history of dyslexia and also possess even mild
syntactic fluency problems in language development (Olson,
1999; Petrill et al.,
2006). Research has suggested
that phonological processing is a key deficit and early
intervention needs to stress these skills, as well as develop
phoneme-grapheme correspondence (Jackson & Coltheart,
2001). A meta-analysis of studies
evaluating phonological intervention found large effects for the
immediate aspect of the intervention, but weaker long-term effects
(Bus & van Ijzendoorn, 1999). The long-term effects on reading,
spelling and reading comprehension after one and one-half years
following the intervention were very small or nonsignificant.
Another study found long-term effects for children who received
phonological training in preschool did show significant
improvement, but again the long-term effect was small yet
significant (effect sizes ranging from 0.33 to 0.39) (Byrne,
Fielding-Barnsley, & Ashley, 2000).
Some main types of programs have purported to do
so include the Reading Recovery Program, Phonological Awareness
plus Synthetic Phonics (PASP) (Torgesen, 2004), Orton-Gillingham approach, Process
Assessment of the Learner (PALS) (Berninger, 2001), and the Lindamood Phoneme Sequencing
Program (Lindamood & Lindamood, 1998). The Lindamood and Fast ForWord programs
were discussed in the language section of this chapter and will not
be discussed further in this section. These programs will not be
reviewed in-depth in this section, but will be described and the
interested reader is encouraged to seek out further information as
wanted. The research indicates that early intervention is
important, but it also suggests that intervention needs to
continue, particularly for children who are at higher risk for
learning problems. This suggestion is supported by a recent study
comparing children who showed significant reading problems with
those exhibiting milder difficulties. Early intervention improved
reading, but did not show long-term effects when intervention ended
(Hurry & Sylva, 2007).
Reading Recovery
The Reading Recovery Program (Clay,
1993) effectively increases
reading achievement of children in the early grades (Ohio
Department of Education, 1995), but does not show continued
progress in later grades when the children again fall behind their
peers (Venezky, 1998). The
program incorporates aspects of whole language while also
emphasizing decoding instruction. Decoding is taught in the context
of reading and writing, where the teacher selects strategies
depending on the child's unique reading problems. It is helpful for
early intervention with less support provided for long-term outcome
if the program does not continue (Chapman, Tunmer, & Prochnow,
2001). Some have suggested the
Reading Recovery does not fully teach phonics, but relies on a
whole language approach, thus children who have significant
problems with phonological awareness are at a great disadvantage
and are not assisted by this approach (Reynolds & Wheldall,
2007).
The research does not support using this program
for children with significant phonological processing deficits. It
may be helpful for those children with orthographic difficulties,
an area that is discussed in the next section of this chapter. The
research also supports the idea that while early intervention is
good, it needs to be continued in order to affect good long-term
outcomes.
Orton-Gillingham
The Orton-Gillingham (OG) method is a systematic
and multisensory approach to reading and writing (Gillingham &
Stillman, 1997). It is an
intensive type of instruction that needs to be accomplished either
on a one-to-one basis or in a small group. A phonetic approach to
reading, it that stresses sound-symbol correspondence, morphology,
syntax, and meaning. It involves training using visual, auditory,
and kinesthetic/tactile learning exercises which have also been
called the Language
Triangle (Gillingham & Stillman, 1997). Children are taught the components for
learning and provided many opportunities to practice until mastery
occurs; assessment of their progress is built into the
program.
A meta-analysis of the research with the OG
method evaluated 12 studies that utilized a comparison group
(Ritchey & Goeke, 2006). Of
the 12 studies reviewed five showed OG instruction was more
effective, compared to all other interventions. Four studies found
improved word reading, word decoding, spelling, and reading
comprehension. Two studies found improvement in vocabulary skills
and only one study evaluated fluency ability. The conclusion from
this review was that there was only one study that evaluated OG in
an experimental fashion and whether this program is experimentally
validated as required by the No Child Left Behind Law (No Child
Left Behind, 2002).
Whether the OG method is feasible for more than a
few children has been challenged in the courts, and the school
districts have won in over 75 percent of the cases brought before a
mediator or a court (Rose & Zirkel, 2007). One of the issues has been the cost of
providing the OG method in a regular school district (Torgesen et
al., 2001). In addition, response
to the intervention (RTI) model and the reauthorization of IDEA
have suggested a shift from the discrepancy model to one that
includes pre-referral interventions provided in the regular
education classroom. Given the shift to early intervention and some
funding for this intervention, the OG method may become more common
in regular school districts as part of RTI (Rose & Zirkel,
2007). However, IDEA’s proposed
regulations require research-based interventions and the research
supporting most of the interventions is not clear and empirically
validated.
The PASP program (Torgesen, 2004) stresses the use of phonological
awareness and decoding ability. Similar to OG and Reading Recovery
programs it stresses systematic instruction in phonemic decoding as
well as in reading comprehension. Research support has not been
reported at this point in time and requires additional empirical
validation prior to becoming a widely accepted program.
Reading comprehension is another area that
requires remediation for many children. Most children that have
difficulties with reading comprehension also have trouble with
decoding skills. Generally, problems are present in vocabulary,
listening comprehension, and working memory and likely underlie
problems with reading comprehension (Leach, Scarborough, &
Rescorla, 2003). Interventions
often require learning how to think about what is being read,
mapping advance organizers on the topic at hand, and utilizing
strategies for reading and learning (Vaughn & Klingner,
2004). A program developed by
Schumaker, Deshler, and McKnight (2002) is designed to directly teach reading
comprehension through the use of metacognitive strategies.
Although phonemic awareness is essential for
early reading success, several researchers have found that
orthographic and visual-spatial deficits are present in some
children with severe reading disabilities. These problems have not
been as well studied as phonological coding. This type of learning
disability will be briefly reviewed next.
Visual/Orthographic Deficits in Reading
Although PRD seems well established, there also
appears to be a smaller group of children who have major
difficulties accessing the orthographic or visual features of
written words (Berninger & Fuller, 1992). Chase and Tallal (1991) describe the sequential order of reading
including the logographic, alphabetic, and orthographic. During the
logographic stage, reading occurs through a visual or graphic
analysis of letters and words (lexical system). Visual memory plays
an important role during this stage, and the child begins to
develop a sight-word vocabulary. The alphabetic stage is
characterized by the phonological decoding (phonological system) of
words using grapheme-phoneme (letter-to-sound) conversions. To
develop into a fluent reader, the child must then proceed to the
orthographic stage, where larger morpheme units (i.e., syllables)
are used. Decoding is quicker during this last stage and this model
assumes that later stages are dependent on skills acquired at
earlier stages. It has been suggested that orthography is a direct
route to understanding meaning of a word while phonology first
requires decoding of the word and then the orthography/meaning
(Harm & Seidenberg, 2004;
Seidenberg & McClelland, 1989). The proposed model of Harm and
Seidenberg (2004) suggests that
orthography and phonology are cooperative and not separate. Both
are tied to semantics with orthography being direct and phonology
being indirect.
Berninger (2001)
describes numerous measures of orthographic coding skills and
methods for assessing the lexical processes of reading. A number of
research tasks have been employed to measure orthographic coding
skills, including pseudohomophone choice (e.g., raiwane), letter
verification, homonym verification, recognition of orthographic
patterns, rhyme judgments with orthographically dissimilar words
(e.g., great-state), and brief exposure of words. Lexical
impairments have been found in a small proportion of children with
dyslexia, although impairment in the phonological system seems to
be a more consistent finding across studies.
There may be a gender difference in orthographic
ability. Some evidence show that males have more difficulty with
orthographic skills compared to women with no difference between
the genders in motor ability (Berninger, Nielsen, Abbott, Wijsman,
& Raskind, 2008a). In
addition, males had more difficulty with accuracy and rate of
reading passages orally both due to orthographic and phonological
problems. Further study is needed in the area of orthography and
its relation to phonology. One of the major studies conducted has
linked orthography to difficulties with written language
(Berninger, Nielsen, Abbott, Wijsman, & Raskind, 2008b). The following section discusses written
language disorders.
Written Language Disorders
Written language impairments are often overlooked
in discussions of learning disabilities. The prevalence of written
language disorders is approximately 1.3–2.7 percent for handwriting
deficits, 3.7 percent to 4 percent for spelling deficits, and 1
percent to 3 percent for written expression (Berninger & Hart,
1992). The most recent estimates
of difficulties in writing have indicated that 69 percent to 77
percent of typically developing students in fourth, eighth, and
12th grades did not meet writing proficiency goals as measured by
the National Assessment of Educational Progress (Graham &
Perrin, 2007b). Children with
specific problems with learning show significant difficulties in
composition, spelling, handwriting, and grammar at higher levels
due to the learning disability (Graham & Perrin, 2007a).
Written language disorders (WLD) can have
profound effects on the academic attainment of older children and
adolescents. In fact, young children with learning disabilities
differ from typically developing children on writing conventions,
while older LD children show significant deficits from typically
developing children on composition skills (Berninger et al.,
2006). Further, children with LD
have difficulty writing narrative text, generating expository, and
finding ideas to write about (Berninger et al., 2006). Men had more significant problems in
writing and spelling, compared to women (Berninger et al.,
2008a). In addition, males had
more difficulty with composition and handwriting although they did
not differ in motor ability.
Neuropsychological Correlates of Written Language Disorders
The extent to which written language disorders
result from right- or left-hemisphere lesions or dysfunction is
still not resolved. The two hemispheres appear to play
complementary roles in writing, with the right hemisphere
(anterior, central, and posterior regions) involved in the
visual-spatial, emotional, and affective components of language
skills, while the left hemisphere (temporalparietal and anterior
regions) is involved in linguistic, speech, and reading processes.
Studies have found that the processing of graphics requires quick
recognition of the spatial features (Coltheart, Rastle, Perry,
Langdon, & Ziegler, 2001) with
teaching of handwriting contributing the visual recognition of
letters (Longcamp et al., 2008).
Areas found through fMRI to be involved in writing include the left
Broca’s area and bilateral inferior parietal lobe. In addition the
fusiform gyrus in the temporal lobe appears to have an area that is
dedicated to word forms which is important for spelling as well as
for writing (Xue & Poldrack, 2007). This region has been implicated in
processing of letter patterns, a skill important for handwriting
and spelling (McCandliss, Cohen, & Dehaene, 2003).
The neuropsychological substrates of WLD have not
been researched as thoroughly as reading and speech-language
disorders. Written language deficits have been found to be
associated with right hemispheric lesions (Aram & Ekelman,
1988). Orthographic mapping, a
skill important for spelling and writing, has been found to be
present in the right frontal gyrus and right posterior parietal
gyrus (Cohen et al., 2002). Direct
intervention in spelling and writing with dyslexic children found
normalization in this region following intensive treatment using
fMRI (Richards et al., 2005).
These changes were related to improvement in spelling of real and
nonwords.
Cognitive Correlates of Written Language
Writing requires motor skills as well as
visual-spatial ability. The child begins learning to write by
copying and tracing figures, and moves to independent production of
these figures as the motor strokes become more automatized.
Teaching generally moves from single letters to connecting letters
to making words through practice and repetition. Studies have
suggested that children respond very well to visual models paired
with practice rather than through practice alone (Berninger &
Amtmann, 2003).
Hayes (1996)
has revised his previous model developed with Flower (Hayes &
Flower, 1986) which includes
planning, translating and reviewing as key issues in writing.
Problem solving and executive functioning skills have also been
implicated in writing. Children with writing difficulties may
experience problems with selective attention which impacts the
ability to plan and write coherently. In addition, there may be
problems with organization and spelling that further impede the
writing process. Handwriting or keyboarding difficulties arising
from motor or visual-spatial challenges can also impede writing
progress and interfere with conveying main ideas. Memory problems
affect word retrieval; spelling; memory for rules of grammar,
punctuation and capitalization, and dysfluent writing. Language
problems may result in impoverished vocabulary, decreased written
expression, dysphonetic (phoneme--grapheme irregularities),
spelling patterns, and poor narration. Working memory is also
important for writing because it allows ideas to be utilized as the
child/adolescent is writing. It is also important for recalling
vocabulary, spelling, and grammar as the writing process continues
(Hooper, Swartz, Wakely, de Kruif, & Montgomery, 2002).
An important area for intact writing ability is
planning and self-regulation (Harder et al., 2006). Planning is closely related to working
memory and the two skills interact. As one writes the ability to
plan what is to be said next and to link it to what has been said
requires working memory (Gregg & Mather, 2002). These skills have been found to be
problematic for children with writing difficulties and have also
been the target for interventions.
Assessment of Written Language Disorders
Written language disorders can be measured using
writing samples taken from the child's academic work or structured
tests. Portfolio or authentic assessment procedures typically
include an analysis of writing samples generated by the child. See
Table 6.1 for a list of commonly utilized standardized
measures.
Informal measures of writing are very helpful in
understanding the difficulties a particular child has in writing.
Task analysis, error pattern analysis, application of the academic
skill, dynamic assessment (e.g., learning efficiency), and process
assessment using the child's curriculum to determine the learning
processes used by the child are several alternative measures that
can be used informally to evaluate the child’s writing skills
(Berninger, 2001).
Interventions for Written Language Disorders
Berninger and colleagues have published
extensively on interventions for handwriting and spelling as well
as for writing composition. A review of the literature as to
interventions for WLD has indicated that a tiered model of
instruction provides the best results for both children with and
without learning disabilities who experience written language
deficits (Graham, Olinghouse, & Harris, in press). Particular
areas that are important to target for intervention at Tier 1
include direct teaching of the ability to plan, revise, and edit a
writing sample. In addition, the ability to set clear goals and
develop an outline, as well as understand how to use the outline to
write a preliminary draft of the writing sample is important, as is
teaching the students how to develop an idea and link it throughout
the writing sample are all crucial to developing appropriate
writing skills (Mason & Graham, 2008).
The second tier includes teaching the student
self-regulation which includes self-monitoring, self-reward, and
instructions as the writing process continues. During this period
of time it was also suggested to utilize student-teacher
conferencing and peer conferencing to discuss progress and any
areas of difficulty that were encountered (Mason & Graham,
2008). Reading and writing need
to be taught together as they are complementary, and writing cannot
be done without also utilizing reading skills (Graves, Valles,
& Rueda, 2000).
Using computers, technology, and web-based
instruction can support basic writing skills and direct teaching,
but cannot be used in isolation (Feretti, MacArthur, & Dowdy,
2000). The use of this technology
in isolation is often recommended for working with children with
written language disabilities (Freeman, MacKinnon, & Miller,
2004). It is important, however,
to emphasize that using computers and technology have not been
empirically validated for WLD (Berninger & Hooper, 2006).
Summary
The emerging evidence in WLD is providing support
to improve our diagnostic and interventional capacity to assist
children in learning how to write. These skills are becoming more
and more crucial for functioning in many positions and for success
in college. WLD often goes hand in hand with RD and needs to be
treated accordingly. There is evidence that utilizing small groups
and providing intensive intervention can assist children with the
process of writing. Difficulties remain for adolescents and college
students with WLD, particularly as writing demands increase (Harder
& Semrud-Clikeman, submitted). More work is needed to
understand early writing difficulties as well as appropriate
interventions for high school and college students.
Learning Disabilities in Mathematics
A sole learning disability in mathematics is
unusual and often found in children with nonverbal learning
disabilities (NVLD). NVLD will be discussed in the next section of
this chapter. The prevalence of mathematics learning disability
(MLD) is approximately 5 percent to 8 percent of school-aged
children (Geary, 2004). It is
unclear from these percentages what proportion of these children
also has a learning disability in reading and/or ADHD. It is also
not clear how MLD and RD differ and whether they arise from two
separate substrates (Mazzocco & Myers, 2003). MLD is similar to RD in that many
processes are involved in mathematics knowledge and a definition
that encompasses all of the complexity of mathematics is not
established at this time. Consequently, the research findings are
varied due to differing definitions, cut-offs, and
conceptualization of what a MLD is.
Geary (2004)
suggests there are three subtypes of MLD. The first is the
procedural subtype. These children’s performance skills are similar
to a developmental delay and their skills often improve with age
and grade. They show frequent careless errors, use their fingers to
count, and do not fully understand the basic processes behind the
task. The second subtype is the semantic memory which continues
throughout school. These children frequently also have a RD, show
problems with memory and retrieval of math facts. This subtype is
hypothesized to be associated with a left hemispheric dysfunction
due to problems with retrieval of information. The final subtype is
called the visuospatial subtype. These children experience problems
with spatial representation, aligning columns, understanding the
relationships between number and quantity, and experiencing
problems with misperception. These children do not show a RD. The
deficit in this subtype is hypothesized to be a right hemispheric
dysfunction. It should be cautioned that there is no empirical
evidence to support this; therefore these are basically theoretical
at this time. The final subtype is reminiscent of the nonverbal
learning disability disorder which is discussed later in this
chapter.
Development of Mathematics Ability
For the typically developing child counting is an
important ability in learning mathematics. Skills such as
one-to-one correspondent counting, correct order of numbers, and
understanding how objects can be sorted and categorized are
important pre-math skills that underlie development. Findings with
MLD children indicate that they do not understand the counting
process that underlies mathematical skills (Hoard, Geary, &
Hamson, 1999).
Arithmetic skills begin with addition which is
based on counting ability. Arithmetic facts become memorized and
then automatized with practice and exposure. As the child becomes
more adept at the calculations, the problems are solved more
efficiently and more quickly with fewer errors (Geary,
2004). Children with MLD
experience significant problems in solving arithmetic calculation
problems. Younger children generally use their fingers to count to
solve the problems; a strategy that becomes less useful as the
facts are automatized. Children with MLD do not move from the
finger counting strategy to automatic processing until the late
elementary years (Geary & Hoard, 2002). In addition, problem solving strategies
and memory retrieval deficits for number facts are not well
established until the MLD child is much older than his/her peers
(Hanich, Jordan, Kaplan, & Dick, 2001; Ostad, 2000). These difficulties may be related to
problems with storing facts and then retrieving them in an
efficient manner (Geary, 2004).
Neuropsychological Correlates of MLD
A review of the literature found that 231
articles were published between 1985 and 2006 studying MLD,
compared to 1,077 for RD in the same time period. Thus, the study
of MLD is in its infancy compared to that of RD or possibly WLD.
Also complicating the situation is the dearth of standardized
measures that are specifically designed to evaluate a
mathematics-based learning disability. This consideration is
important because standardized tests often measure overall
calculation and reasoning skills, but do not evaluate number sense,
counting skill and other components important for mathematical
reasoning (Murphy, Mazzocco, Hanich, & Early, 2008).
Murphy et al. (2008) evaluated three groups of children using
varying definitions of MLD. One group had mathematics ability in
kindergarten measured at or below the 10th percentile, one group
had scores between the 11th and 25th percentile, and the final
group had scores above the 25th percentile on the Test of Early
Math Ability (TEMA-2) (Ginsberg & Baroody, 1990). These children were evaluated in
kindergarten and again in third grade. Measures included reading
cluster from the WJ R, visual-spatial ability, rapid automatized
naming tasks, and the Contingency Naming Test as a measure of
working memory (Anderson, Anderson, Northam, & Taylor,
2000). It was found that the
mathematics skills of the two highest scoring groups increased at a
faster rate than for the children in the lowest performing group.
The middle group did show a lag that continued into third grade,
compared to the typically achieving group. These differences
continued at the same rate indicating that, while not as severe as
the low performing group, the middle group continued to lag in
mathematics ability. In addition, the low achieving group appeared
to reach a plateau that wasn’t seen in the two higher achieving
groups, suggesting that further improvement was unlikely without
intensive intervention. All groups differed on the counting task
particularly in identifying errors that were made.
An assessment of related neuropsychological
factors found that IQ, visual-spatial ability, and rapid number
naming predicted group membership at the entry level. IQ and
visual-spatial ability were not predictive of growth rates while
rapid naming of numbers was particularly for the lowest achieving
group. Reading ability was related most strongly to progress for
the lowest achieving group and was also present as a predictor for
the middle achieving group, albeit in a weaker manner. Working
memory skills were related to mathematics difficulty as well as
progress for all groups. Poorer working memory ability was related
to efficiency in solving mathematical problems.
Executive functioning appears to be a problematic
area for children with MLD. In order to solve a mathematical
problem one not only needs the basic facts and operations readily
at hand, but must also focus attention to the task at hand and
inhibit responding to irrelevant material (Blair, Knipe, &
Gamson, 2008; Geary,
2004). These skills, plus working
memory, are important for success in mathematics,but children with
MLD appear to have problems with these skills. Children with MLD
show concurrent difficulties on tasks that measure executive
functioning, particularly in the areas of working memory and
inhibition (Mazzocco & Kover, 2007).
Children with MLD are less accurate, compared to
their peers, in evaluating whether answers to specific arithmetic
problems are correct or not. This difficulty is related to the MLD
child’s ability to monitor what is being asked of him/her and
evaluating whether the correct response has been provided. Such
self-checking is an important aspect of mastering arithmetic facts
and processes (Garrett, Mazzocco, & Baker, 2006).
Neurological Contributions to Mathematics Skills
Mathematicians have increased parietal gray
matter bilaterally and increased volume of the bilateral inferior
frontal lobes. These regions have been implicated in arithmetic
calculation and visuospatial processing. Morphometric differences
have been found in the brains of accomplished mathematicians,
musicians, and scientists in the parietal lobes. Larger parietal
regions and more gyral formations have been linked to stronger
mathematical skills in adults (Spitzka, 1907; Witelson, Kigar, & Harvey,
1999). Brain differences may be
due to experience and/or genetic disposition. Studies have found
that brain differences can be associated with intense learning.
Studies of children with early and intense musical training have
found morphological differences in these children compared to
controls (Gaser & Schlaug, 2003; Hutchinson, Lee, & Gaab,
2003; Munte, Altenmuller, &
Jancke, 2002). Brain structural
changes have also been linked to intensive training in
undergraduate and graduate students in medicine, with increases in
the bilateral parietal cortex as well and hippocampus in
post-versus pre-testing (Dragnanski et al., 2006). These increases were associated with
learning abstract material. Whether increased volume in the
parietal and hippocampal regions are present at earlier ages has
not been studied. What differences may be present at an earlier age
in students who are mathematically and scientifically disposed, and
how these differences change with exposure and training, are
important questions for further study. Long-term training in a
mathematical discipline may lead to brain changes that support
mathematical ability.
There are studies that link brain changes to
practice and experience with mathematical concepts. These studies
have generally utilized structural (anatomical) data. While high
ability has been linked to expertise in a field, differences in
brain structure may be due to more than solely intelligence, and
are specific to mathematics-based talent (Rickard et al.,
2000). Very few studies have been
conducted that involve brain activation in adults with
mathematics-based interests, and no studies have linked
developmental brain activation and structural changes in
participants with math-based skills and interests. No studies were
found that evaluate neuroimaging in children with mathematical
disabilities.
Implications for Assessment
As described in
Chapter 6, there are several standardized
measures that evaluate reading, mathematics and written language.
There are very few specially developed tests just for mathematics.
To evaluate mathematical skills standardized tests need to be
supplemented with curriculum-based materials. These materials need
to evaluate the child’s counting ability, understanding of
quantity, knowledge of concepts, and ability to check one’s work.
One of the main tests used to evaluate mathematics directly include
the Key Math Diagnostic Arithmetic Test-3 (Connolly, 2007). The test is designed for students aged
four years, six months to 21 years and meets the criteria
established by the National Council of Teachers of Mathematics in
2000. Its measures evaluate numeration, algebra, geometry,
measurement, probability, mental computation, basic fact knowledge,
problem solving, and estimation.
For younger children, the Test of Early
Mathematics Ability-3 (Ginsburg & Baroody, 2002) measures basic number understanding as
well as beginning comprehension of quantity and mathematical facts.
Evaluating the child’s ability to count, to understand quantity
through a number line, and having the child rapidly name numbers
are other methods for understanding a child who is at risk for
learning problems in mathematics. There is emerging evidence that
children who experience difficulty with phoneme-grapheme
correspondence may also have problems associating numbers and
symbols (Wills, 2007).
Implications for Interventions
As stated above, drilling on mathematical facts
is helpful only up to a point. Using visual cues as well as
experiential materials may be very helpful for a child who has not
mastered the concepts of basic math (numerosity, quantity, etc.).
Cuisenaire rods are a series of color-segmented rods with different
colors representing numbers from 1 to 10. Children are able to mix
and match the colors to understand adding (2 red rods each equal to
5 make 10) or subtracting rods as desired. Other visual aids such
as number lines can also help children understand how numbers
relate to each other.
Word problems can be problematic for children who
have difficulty understanding the words as well as the processes
that are required. Fuchs et al. (2004) evaluated third-grade students to evaluate
how word problems are solved. The children were provided with
intervention to assist with understanding word problems and
developing strategies to solve future problems. This intervention
improved functioning in typically developing children apart from
knowledge that they would have gained from practice (aligning
columns, understanding particular words and symbols, etc.). When
these interventions were applied to children who were below grade
level in mathematics, they also made improvement following
intervention (Fuchs et al., 2003a). When these strategies and
self-monitoring strategies were further evaluated in low achieving
samples of children in mathematics, these children had more
difficulty, particularly in setting realistic goals based on their
performance (Fuchs et al., 2003b).
Thus, teaching basic executive functions may assist in helping
children with MLD to improve.
Summary
Based on this brief review of the literature on
MLD, there are many areas of inquiry that are incomplete in our
understanding of mathematically based learning disability.
Neuroimaging of children with MLD has not been published at this
point in time and it is not clear what the neurological
contributions to mathematical difficulty are. While there is
evidence that excellence in mathematical ability may be related to
enhanced parietal lobe functioning, neuroanatomical and
neurofunctional differences in children with MLD and those without
have not been demonstrated. As the research continues to produce
results, findings as to best practices for assessment and
intervention will assist in our understanding of this disorder both
with and without co-occurring reading disability.
Nonverbal Learning Disabilities
In a series of studies (Rourke, 1989, 1995;
Rourke & Tsatsanis, 1996),
Rourke and colleagues introduced the concept of a syndrome,
nonverbal learning disability (NVLD), based on the presence of an
intact left hemisphere with dysfunctional right-hemisphere systems.
The interplay between basic neuropsychological deficits and assets
result in complex social-emotional and academic difficulties.
The definition of a nonverbal learning disability
is problematic and varies among researchers and clinicians.
Children with NVLD generally show a different pattern of strengths
and weaknesses compared to children with LD. In contrast to
children with LD who show difficulties in phonological processing,
children with NVLD frequently do fairly well in single word reading
and in spelling. Children with NVLD have significant problems with
mathematics calculation, frequently misalign the columns in the
computations, and have problems learning basic mathematics facts.
They have particular difficulty in recalling information that is
complex or novel, but do very well with rote memory or information
that can be recalled by verbal means (Rourke, 1995). Many children with NVLD have difficulty
with fine and gross motor development and experience problems in
learning to skip, tie shoes, and to write legibly.
Children with NVLD also have difficulties
understanding nonverbal input in social situations and,
subsequently, are socially isolated. They are infrequently chosen
in games and often socially isolated. Significant problems are
described in the child’s ability to correctly perceive social
relationships and with social judgment. In several instances the
child experiences difficulty with relating to peers. Many children
with NVLD relate better to adults and may cling to teachers and
parents as a way of adapting to a confusing social situation. Many
children with NVLD also have a tendency to show attentional
difficulties and may qualify for an additional diagnosis of ADHD:
predominately inattentive. An increased incidence of mood disorders
has been found in older children with NVLD.
Children with NVLD have particular difficulties
understanding situations that are novel and complex (Rourke &
Fuerst, 1991). Particular difficulty is present in understanding
situations that involve cause-effect reasoning and with generating
solutions to problems (Semrud-Clikeman, 2001). Language skills are generally well
developed for basic skills, but problems are also present with more
complex language, understanding figurative language and idioms, and
with incongruities frequently seen with the understanding of humor
(Semrud-Clikeman & Glass, 2008). Difficulties with social
conversation as well as reciprocity in relating to others can
significantly affect the NVLD child’s ability to enter into peer
relations, a skill that becomes more important with
adolescence.
Rourke and colleagues (2002) characterize the
NVLD disorder as having several principal features, including:
-
bilateral tactile-perceptual deficits more pronounced on the left side of the body than the right,
-
bilateral coordination problems—again more on the left than right,
-
problems with visual, spatial, and organizational abilities,
-
problems adapting to novel and complex situations—use of rote or literal interpretation of behaviors that frequently result in inappropriate behavior,
-
difficulty with problem solving—more evident with nonverbal than verbal materials and situations,
-
problems with benefiting from positive and negative feedback,
-
a distorted sense of time,
-
well developed rote verbal memory,
-
highly verbose with much repetition of previously stated ideas,
-
poor speech intonation (prosody),
-
problems with mathematics calculation with relative strengths in reading and spelling, and
-
problems with social judgment, social perception, and social interaction skills.
Some studies have not supported this
conceptualization, particularly in regard to the difficulty in
motor and perception skills (Wilkinson & Semrud-Clikeman,
2008). Areas that have received
support in research include prosody, attention, mathematics
problems, social judgment difficulty, and challenges with problem
solving (Semrud-Clikeman & Fine, 2008). Many clinicians and researchers utilize
diagnoses that include 3–5 of the symptoms listed above. There is
little empirical evaluation of this process and further study is
needed. It is not clear which of the symptoms are required for a
diagnosis and which are correlated. For example, some children may
show visual-spatial and mathematics problems, but do not have
difficulty with social understanding. Others do not show verbal
performance differences and yet have social difficulty,
visual-spatial problems, and mathematics difficulty. A discriminant
analysis of a large database of children with NVLD, ADHD, LD, and
ASD found that the single most salient predictor of group
membership for NVLD was social functioning (Fine, Semrud-Clikeman,
Reynolds, & Smith, submitted). Similar studies need to evaluate
which of the symptoms in this disorder are primary and which are
correlated in order for a better understanding of what NVLD is and
how to diagnose the disorder. See Table 12.2 for a summary of
research investigating the neuropsychological, cognitive, academic,
and psychosocial features of the NVLD syndrome.
Table
12.2
A summary of specific deficits associated
with Nonverbal Learning Disabilities (NLD)
Biogenetic
Factors
– No known correlates
|
Environmental
Factors/Prenatal/Postnatal
– NLD appear at or soon after birth
– Neurodevelopmental disorder or may be
caused by traumatic injury
– Few details on environmental impact
|
||
Temperament
– No known correlates
|
Birth
Complications
– No known correlates
|
||
CNS
Factors
– White matter dysfunction
– Intermodal integration (callosal
fibers)
– Right-hemisphere involvement
|
|||
Neuropsychological Factors
– Bilateral tactile deficits (pronounced on
left side)
– Visual-spatial-organizational
deficits
– Complex psychomotor deficits
– Oral-motor apraxia
– Concept formation and problem-solving
deficits
|
|||
Intellectual
– Concept formation
– Strategy generation
– Hypothesis testing
– Cause-effect relations
– Little speech prosody
– Formal operational thought
|
Perceptual Memory
– Visual discrimination
– Visual detail
– Visual relation
|
Memory
– Tactile
– Nonverbal
– Complex information
|
Attentional
– Tactile
– Visual attention
– Attends to simple, repetitive verbal
material
|
Academic/Behavioral
– Graphomotor
– Reading comprehension
– Mechanical arithmetic
– Mathematical reasoning
– Science
|
Psychosocial
– Adapting
– Overreliance on rote behaviors
– Externalized disorders (conduct, acting
out)
– Social perception and judgment
– Social withdrawal or isolation
– May develop internalized disorders (e.g.,
depression, anxiety)
|
Family
– Research is sparse
– Social interaction skills
|
The NVLD model is a culmination of 20 years of
research investigating the neurocognitive basis of learning and
social-emotional functioning in children (Rourke & Tsatsanis,
2000), and is an extension of the
Goldberg and Costa model (Goldberg & Costa, 1981). Rourke (1989) summarizes two major
functional-anatomical differences between the hemispheres:
- 1.
The left hemisphere has greater cortical representation in specific sensory modalities (in temporal, occipital, and parietal areas) and in the motor cortex, whereas the right hemisphere has more association cortex (temporoparietal and prefrontal areas) than the left.
- 2.
The left hemisphere has more intraregional connections, while the right has more interregional connections.
These basic differences led Goldberg and Costa
(1981) to conclude that the right
hemisphere has a greater capacity for dealing with “informational
complexity.” Rourke (1989)
further incorporates neurodevelopmental theory and discusses the
role of the right hemisphere cognitive and emotional adjustment in
children. Rourke proposes that the right hemisphere is more
important than the left for activating the entire cortex,
processing novel information, developing new descriptive systems,
and processing complex information. The left hemisphere is more
adept than the right at applying already learned descriptive
systems that use discrete units of information (like language), and
for storing compact codes (Rourke, 1989).
Genetic Factors
To date there are no studies addressing the
genetic basis for the NVLD syndrome. The extent to which genetic
factors play a role in this neuropsychologically based learning
disorder certainly warrants investigation. There are indications
that some genetic syndromes may have profiles that are similar to
those described for nonverbal learning disabilities, including
Turner syndrome and Velocardiofacial syndrome.
Turner Syndrome
Turner Syndrome (TS) is the loss of some or all
of the X chromosome. It is rarely seen in males and has an
incidence of 1 in 3,000–5,000 live births in females (Rovet,
2004). Females with TS lack
estrogen and often have ovarian dysgeneration and infertility. The
neuropsychological profile present in TS includes significant
problems processing social information, visuospatial information,
and severe mathematics disabilities. Performance IQ is generally 15
points lower than verbal IQ, which is generally in the average
range (Rovet, 2004). Other areas
that are frequently affected include working memory, face
processing (Lawrence et al., 2003), mental rotation, spatial reasoning, and
difficulty processing emotions (Elgar, Campbell, & Skuse,
2002; Lawrence, Kuntsi, Coleman,
Campbell, & Skuse, 2003). The
mathematics, working memory, and visuo-spatial difficulties have
been found to be present developmentally and continue throughout a
child’s life (Murphy & Mazzocco, 2008; Murphy, Mazzocco, Gerner, & Hendry,
2006).
Structural imaging has found differences in
children and adults with TS in smaller volumes in the areas of the
occipital and parietal lobe and reduced volume in the caudate,
thalamus, and hippocampus (Reiss, Eliez, Schmitt, Patwardhan, &
Haberecht, 2000). Larger volumes
compared to controls have been found in patients with TS in the
temporal lobes, amygdala, and orbitofrontal gray matter (Brown et
al., 2002; Good et al.,
2003).
The finding of anamolous development in the
amygdala is similar to research in autism (see Chapter 10 for further information.
Patients with TS have abnormal responses to fear recognition and
other types of negative facial expressions which may be related to
the anomalous amygdaloid and orbitofrontal regions. These
structural differences, coupled with the neuropsychological
correlates of NVLD, have lead some to speculate that there may be
similar underlying neurological differences between these
disorders. Further study is needed to determine whether there is a
commonality in connectivity, functionality, and neuropsychological
findings that underlie both TS and NVLD.
Velocardiofacial Syndrome
Velocardiofacial syndrome can also exhibit
deficits in visual-spatial skills, social processing, and
mathematics reasoning (Swillen et al., 1999). Velocardiofacial syndrome occurs with a
deletion on chromosome 22 and many of these patients show
neurological, cognitive, and behavioral deficits (Murphy, Jones,
& Owen, 1999). Imaging has
found differences in the white matter, particularly in the parietal
regions of the brain (Amelsvoort et al., 2001; Eliez, Schmitt, White, Hu, & Reiss,
2002). Diffusion Tensor Imaging
(DTI) has found alterations in the white matter tracts in the
parietal lobes as well as in the frontotemporal regions bilaterally
(Barnea-Gorly et al., 2003).
Agenesis of the Corpus Callosum
While not a genetic disorder per se, agenesis of
the corpus callosum (AC) occurs at some point during gestation when
the corpus callosum (a large bundle of fibers that connect the two
hemispheres) either forms incompletely or not at all. Children with
AC range in ability from mentally retarded to having average
ability. For those children with average ability difficulty appears
to be present for novel problem solving, as well as social
understanding (Brown & Paul, 2000; Paul, Schieffer, & Brown,
2004). In addition, children with
AC also have trouble understanding figurative language as well as
affect as expressed by speech intonation (Brown, Symingtion, Van
Lancker-Sidtis, Dietrich, & Paul, 2005; Paul, Van
Lancker-Sidtis, Schieffer, Dietrich, & Brown, 2003).
These findings certainly suggest a similarity to
NVLD. Studies that compare children with AC, children with NVLD,
and children with other genetic syndromes that have similar
features would be informative as to what these disorders have in
common and whether there are discriminating aspects of these
issues. If there are similar behaviors that arise from similar
neurological underpinnings but different causes, it may well be
that the disruption of connectivity in particular regions of the
brain relates to social, visual-spatial, and mathematical
difficulties. Some studies of children with TS have contrasted
their functioning in mathematics to that of children with Fragile X
and found similarities (Murphy & Mazzocco, 2008). Unfortunately, social functioning
measures were not also obtained in these studies. This area of
research is ripe for further investigation.
Prenatal/Postnatal Factors
The NVLD syndrome is described as a
neurodevelopmental disorder; that is, one that is present at or
soon after birth (Rourke, 1989).
While Rourke (1989) does assume
that the neuropsychological patterns of assets and deficits are
developmental in nature, appearing at birth, he does acknowledge
that traumatic injury or trauma may result in a similar pattern.
Few other details are available describing prenatal and postnatal
factors associated with the NLD syndrome.
One of the theories about NVLD is that it
involves right hemispheric dysfunction. It has been suggested that
development of the right hemisphere can be affected by many issues
including hormones during gestation, prematurity, pregnancy and
delivery complications, among others (Forrest, 2007). During development the right hemisphere
is believed to grow first, followed by the left hemisphere and
finally connectivity between the two hemispheres and hemispheric
specialization (Thatcher, 1996).
Similarly, Luria suggests that within the lobes hierarchical
development occurs, moving from primary centers (hardwired centers)
to more associative and highly complex areas that are important for
problem solving and insight into behavior (Luria, 1980).
Neuropsychological Correlates
Rourke (1989)
lists the neuropsychological assets of the child with NVLD as
auditory perception, simple motor skills, rote memory, verbal and
auditory memory, attention to verbal and auditory information, and
verbal reception, storage, and associations. Neuropsychological
deficits associated with the right hemisphere NLD syndrome include
tactile and visual imperception, impaired complex psychomotor
skills, inattention to tactile and visual information, poor memory
for tactile and visual information, and some verbal skill deficits
(i.e., prosody, semantics, content). Scores are also below average
on subtests of the Performance Scale of the WISC-R (Block Design,
Picture Arrangement, and Object Assembly): the Tactual Performance
Test, left hand; the Pegboard Test, both right and left hands, and
the Category test (Rourke, 2000).
Academic and School Factors
The interaction between right hemisphere
weaknesses and left hemisphere assets is manifested in good
graphomotor skills for right-handed children (usually later in
life), word decoding skills, spelling skills, and “verbatim memory”
(Rourke, 1989). Because children
with NVLD rely heavily on intact left hemisphere functions, they
often develop excellent reading, decoding, and spelling skills
(Semrud-Clikeman, 2007). Children
with NVLD tend to perform well on academic tasks that rely on rote
verbal memory.
Academic deficits include poor academic
achievement in mathematical reasoning and computation. Initially
the child with NVLD shows good reading recognition, but in later
grades as reading for meaning becomes more important, the child
experiences significant problems with reading comprehension. These
academic areas are particularly compromised by difficulties with
abstract reasoning and deduction. Children with NVLD fail to
develop complex concept formation and problem solving abilities
needed for advanced subject matter such as physics
(Semrud-Clikeman, 2003).
Although children with NVLD start out with slow
development of early graphomotor skills, these abilities improve
with age. Academically, children with NVLD appear to be compromised
by their extreme difficulties with understanding cause-and-effect
relationships, and problems generating age-appropriate problem
solving skills. These deficits are particularly evident during
novel tasks, and subsequent learning is negatively affected
(Semrud-Clikeman, 2007).
Visual-Spatial Ability
Visuospatial skills, visual working memory, and
imagery in children with NVLD are areas of significant difficulty
(Cornoldi, 1999). Visual imagery
and working memory have been linked to the ability to process
social information, an area that is difficult for children with
NVLD (Logie, 1995). Children with
NVLD have trouble recalling visual and spatial information as well
as imagery for both verbal and visual information. Thus, difficulty
is present on tasks that require the child to learn new information
by associating it with previously learned material. It is suggested
that visual working memory is an area of particular difficulty and
support is required to assist with these abilities.
The ability to integrate information presented
visually may be a primary difficulty for children with NVLD who
have more difficulty on measures of visual-motor integration and
visual-spatial skills, compared to children with ADHD or typically
developing children (Wilkinson, & Semrud-Clikeman, 2008). When
the performance of children with verbal LD, NVLD and typically
developing children were compared on measures of visual motor
integration (Foss, 1991; Meyers & Meyers, 1995), the children
with learning disabilities performed more poorly than typically
developing children. The children with NVLD, however, performed the
most poorly. Qualitative analysis of the findings indicated that
children with verbal LD were generally able to copy the picture
adequately, but missed many details. The children with NVLD copied
the picture in a piecemeal fashion with disconnected details. This
disjointed understanding of the whole from the parts likely
interacts with difficulties with social perception.
An evaluation of the perception of children with
NVLD using projective measures found that they had significant
difficulties in perceiving the inkblots in a typical manner
compared to controls and children with ADHD: PI (Corlett,
2002). The difficulty that was
present was characterized by problems with integration. No
differences were found between the ADHD: PI and control groups,
thus attentional deficits were not at the core of the problems with
visual integration. Thus, it is likely that children with NVLD will
have difficulties integrating visual input accurately and may react
inappropriately. Although children with NVLD scored on indices
indicating interest in others, their responses indicated they are
likely to react inflexibly to a social situation.
These studies indicate that children with NVLD
have difficulty with visual-spatial integration that may relate to
the frequently encountered problems with social processing. These
difficulties in understanding novel events, processing materials
quickly, and putting together parts of a scenario to understand the
underlying meaning likely interfere with social processing. In
addition, if the infant has difficulty deciphering faces and
understanding facial expressions, it is likely that the early
building blocks of social understanding are not well established
and carry over into later childhood (Semrud-Clikeman & Hynd,
1990).
Attention
Attentional skills are problematic for children
with NVLD and many are diagnosed with ADHD: predominately
inattentive type (Semrud-Clikeman, Walkowiak, Wilkinson, &
Christopher, submitted). Attention to complex, novel information is
particularly difficult, and children with NVLD are more attentive
to simple, repetitive tasks than to tasks that are verbal or
auditory in nature. This attentional bias makes new learning
particularly difficult, and becomes more prominent with age.
Children with NVLD often appear overactive initially, but this
apparent hyperactivity does not persist.
Executive Functioning
The skills of working memory, processing of
complex and novel material, and understanding of other’s motives
and feelings is related to difficulty with executive functioning
for these children. Executive functions are those that allow a
person to view their behavior, assess its appropriateness, and make
changes if required. They differ from cognitive functions somewhat;
cognitive functions look at what a person knows while executive
functions evaluate the person’s ability to carry through with a
plan of action (Damasio, Tranel, & Rizzo, 2000). Thus, a child or adolescent can know the
appropriate plan of action in a social situation, but be unable to
carry through with it in an efficient manner. Often fluid social
interaction require the child to process information quickly and
efficiently generally using simultaneous evaluation of many aspects
of the difficulty.
Children with NVLD perform better skills on
measures of sequential processing than those of simultaneous
processing. Simultaneous and sequential processing are based on
Luria’s (1980) model of brain function that conceptualizes the
brain function into three networks that function independently and
are integrated at higher levels. The three networks are planning,
arousal, and processing (simultaneous as well as sequential).
Sequential processing is the ability to process information in a
step-by-step manner and is primarily based on left hemispheric
processing. Simultaneous processing is a right hemispheric function
and allows the individual to process information with many facets
and form an integrated whole. The individual uses either style
depending on the task at hand. Chow and Skuy (1999) evaluated children with NVLD and those
with verbal LD on measures of sequential and simultaneous
processing. Children with verbal LD were more likely to use the
simultaneous processing style while children with NVLD favored the
successive processing mode.
This difficulty in understanding the gestalt of a
task, or social exchange, likely interferes with the ease of social
interactions. If the child with NVLD is attempting to understand a
perceptual task using an inefficient method (such as sequential,
language-based processing), the behaviors are likely to feel flat
and inappropriate to the fellow person in the interaction.
Difficulties with fluid reasoning, concept formation, and problem
solving have been identified in children with NVLD (Schnoebelen,
Semrud-Clikeman, Guli, & Corlett, 2002). These difficulties interact with the
problems in processing perceptual information, particularly when it
requires the processing of novel and complex social information.
The problem that children with NVLD have in social interactions may
be a combination of difficulty with attention, executive
functioning, and perception (Semrud-Clikeman & Schaefer,
2000).
Social-Psychological Functioning
The difficulty children with NVLD have
understanding complex pictures underscores the challenges present
in comprehending dynamic social exchanges. These difficulties with
integration make it problematic for the child with NVLD to
understand facial expressions and pair them with gestures and
language. When asked to interpret a scene where the verbal portion
of the communication does not match the nonverbal portion, children
with NVLD inevitably use the verbal portion to translate meaning.
Thus, sarcasm or humor is not understood by children with NVLD and
they often translate this type of communication literally
(Semrud-Clikeman & Glass, 2008). Moreover, children with NVLD
often make inferences based on language and interpret a situation
using details without reference to the context (Worling, Humphries,
& Tannock, 1999). Thus, the
child’s interpretation may not be accurate for the context in which
the information is given and, subsequently, his/her behavior is
often inappropriate based on misperceptions.
Borod, Andelman, Obler, Tweedy, and Welkowitz
(1992) suggest that interpretation
of emotion requires the ability to understand the relationship
between emotions which in turn requires spatial organization—a
right hemispheric integrative function. Working memory deficits
present in NVLD also limit the child’s ability to apply appropriate
emotional inferences to the situation at hand. It is likely that
this system becomes overloaded attempting to process the details
involved in any social exchange, thus resulting in difficulty with
social interacting that is fluid and reciprocal.
To more fully understand the prevalence of
psychopathology in children with NVLD compared to those with RD, a
study contrasted typically developing children, children with NVLD,
RD, a psychiatric control group, and a group of children with
velocardiofacial syndrome (VCFS) to determine what differences may
be in the prevalence rate of psychiatric disorders (Antshell &
Khan, 2008). Each parent was
interviewed to determine the presence of psychopathology. The NVLD,
RD, and psychiatric control groups were found to show a higher
incidence of ADHD and substance abuse/dependence. The psychiatric
controls and children with NVLD were also found to have a higher
prevalence rate of familial bipolar disorder. This finding was not
true for the velocardiofacial group who also had NVLD. It was
concluded that the children with VCFS and NVLD were different
genetically compared to the NVLD without VCFS. The conclusions from
this study are interesting in that the authors related NVLD to
bipolar disorder. This conclusion of increased bipolar disorder in
the families of children with NVLD has not been replicated
(McDonough-Ryan et al., 2002).
Further study is needed in these areas to more fully understand the
link that may exist between NVLD and other psychiatric
disorders.
The areas of attention, executive functioning,
social understanding, and academic functioning are domains that
need to be evaluated by a neuropsychologist. Each of these regions
requires varying types of measures. The following section discusses
what measures may be most helpful in this evaluation.
Neuroimaging in NVLD
The only studies completed on neuroimaging in
NVLD are case studies. In one case two adolescents with NVLD and
two controls were asked to utilize self-talk to complete a task and
then to use solely tactile information (Tuller, Jantzen, Olvera,
Steinberg, & Kelso, 2007).
Each adolescent was asked to touch his thumb to each of his
fingertips in the same hand. Results from the fMRI found that the
two subjects with NVLD showed a widely distributed network when
completing this task, compared to the controls. One of the
difficulties with this study is the low number of subjects and the
difficulty in knowing whether these results truly represent the
functioning of children with NVLD or whether they solely represent
normal fluctuation among individuals.
One study evaluated a 14-year-old boy with
cerebral palsy who was diagnosed with nonverbal learning
disabilities as well as executive function deficits and
visual-spatial delays (Gross-Tur, Ben-Bashat, Shalev, Levav, &
Sira, 2006). He had a
developmental hypoplastic left cerebellum. A reduction in right
hemispheric white matter in the cerebrum as well as in the
cerebellum was found via DTI. The conclusion from this study was
that the disruption of the right hemispheric circuits negatively
influenced the child’s ability to relate to others, complete
visual-spatial tasks, or plan and organize information. There were
no other specific studies that evaluated NVLD using neuroimaging in
our recent literature review.
Implications for Assessment
Comprehensive neuropsychological assessment is
necessary to identify the NVLD syndrome in children. A
developmental model of assessment, where evaluations are repeated
over time and form the basis for remedial programs, has been
recommended (Rourke, 1994). Based
on the above descriptions of difficulties children with NVLD
experience it would be recommended to include measures of
attention, executive functioning, and academic performance. Many of
the measures listed in Chapter
6 are appropriate for this evaluation. Particular
recommendations would be for the sorting, Stroop, and Tower tests
from the Delis-Kaplan Test of Executive Functioning, the
Rey-Osterreith, the TOVA, the WJ III Tests of fluid reasoning, and
a full evaluation of the child’s mathematical and reading
abilities.
In addition to these measures, it is also
imperative to evaluate the child’s social abilities. There are few
good direct measures of social functioning. One measure that has
been helpful in our work is the Child and Adolescent Social
Perception Test (CASP (Magill-Evans, Koning, Cameron-Sadava, &
Manyk, 1996). This measure is a series of videotaped vignettes of
children, adolescents and adults interacting. The videotape shows
the action with the words masked so that what the child hears is
the intonation, but not the words. After each of 10 vignettes, the
child is asked questions about what happened and what the people
were feeling. Two standard scores are provided, one for nonverbal
cues and one for emotion recognition. The psychometric properties
of the measure are acceptable, but further research is needed to
determine whether the scores can discriminate among groups of
children with disabilities.
Fine, Semrud-Clikeman, Butcher, and Walkowiak
(2008) evaluated the use of the CASP with children with attention
problems and those with social competence problems with and without
attentional issues. While attention played a part in the
performance on this measure, the CASP identified children with
social difficulties even with attentional aspects removed. While
the CASP is helpful and one of the few things available, the
vignettes are a bit dated and its use for younger children may be
questionable. It can be ordered by contacting Dr. Magill-Evans at
the University of Alberta in Edmonton, Canada.
Other measures that have recently become
available include the Social Communication Questionnaire (SCQ)
(Rutter, Bailey, Berument, Lord, & Pickeles, 2003). The SCQ is completed by the parent and
provides a total score that indicates the child’s likelihood for
autism. While it is a screener for autism and shows severity of
difficulty, it is a measure that can also be used with children
with NVLD to pinpoint problem areas. The authors report that the
SCQ is not affected by age, gender, language skills or performance
ability. The utility of the SCQ for diagnosis of autism has been
established; its use with NVLD would be to assist with
understanding the social areas for which the child has
difficulty.
The Social Responsiveness Scale (Constantino
& Gruber, 2006) is a parent
report for children aged 4–18 years. It can be completed by a
parent or teacher and evaluates the child’s functioning within a
natural social setting. The areas of reciprocal social
communication, social anxiety/avoidance, preoccupations, social
awareness and social impairments are evaluated. It provides
information about the level of difficulty in each of the areas of
concern. There are five treatment subscales in addition to the
total score. These subscales are receptive, cognitive, expression,
and motivational aspects of social behavior and autistic
preoccupations. It differs from the SCQ in that it doesn’t use a
cutoff score, but rather utilizes a scale that provides a measure
of severity for each of the subscales. This instrument is fairly
new and further research is needed to determine how useful it will
be for evaluating children with NVLD. It is, however, a measure
that can be helpful in evaluating the child’s social performance in
school and home.
Evaluating the child’s functioning in all of
these domains should also provide ideas as to appropriate
interventions. The interventions often need to be tailored to the
individual child and empirical validation of these methods is not
as strongly established as for other types of learning disorders.
The following section briefly reviews one particular type of
intervention that has provided some empirical validation.
Implications for Intervention
According to Rourke, when systems of the right
hemisphere are dysfunctional and systems of the left hemisphere are
relatively intact, the child tends to engage in perseverative or
stereotypic responses because of the over-reliance on information
that has already been learned. This often results in difficulties
in developing problem solving strategies and generating alternative
solutions. Children begin to develop compensatory skills that are
primarily verbal in nature, and they begin to avoid novel
situations. Because of tactile deficits and slow maturation of
early psychomotor skills, children with NVLD have a tendency to
avoid active exploration of the environment.
Intervention programs that incorporate early
teaching in sensory-motor integration as well as interventions that
are implemented across all domains (i.e., academic and
psychosocial) include the child as well as the parent. Methods that
increase social awareness, teach problem solving strategies,
encourage generalization of strategies, and improve verbal skills
should be part of the intervention plan. Methods for strengthening
areas of weakness in visual-spatial areas, interpreting competing
stimuli, teaching nonverbal behaviors, providing structure for
exploration, using concrete aids, teaching self-evaluation, and
developing life skills are important aims for any
intervention.
The social skills curriculum developed for other
children has proven to be a successful intervention without
tailoring the skills to the child with NVLD (Palombo,
2006; Semrud-Clikeman &
Schaefer, 2000). Most social
skill programs begin at a level that is likely too advanced for
children with NVLD as these programs generally assume that the
child is able to accurately interpret facial expressions and body
language. For many children with NVLD (and for those with HFA and
AS) the interventions need to begin with labeling of emotions and
understanding emotional labels to be effective. In addition,
interventions need to be based on teaching social perception
through the use of practice, modeling, and role-playing. Breaking
social perception down into discrete steps and teaching rules to
allow the child with NVLD to process the information verbally plays
on the strengths that these children bring to the program. Pairing
auditory and visual stimuli together may also provide the type of
support that is necessary for the child to fully understand the
complex nonverbal social communication that is problematic for
his/her interpretation (Semrud-Clikeman, 2007).
In order for these interventions to be helpful to
children with NVLD it is likely important that the program begin
slowly and with a great deal of structure, and then gradually move
to the more complex activities that require the building of trust
in order to attempt them. Practicing the skills as well as
overlearning key social abilities and perceptions is crucial not
only for mastering these abilities, but for later generalization.
To encourage generalization of the skills, it is important to
involve the parents so they can help practice the newly learned
skills at home and in school, and teach these children how to apply
the social skills appropriately.
Generally the interventions fall into one of
three types: parent interventions, social skills curriculum
(including coaching and friendship groups), and a group-based
intervention based on learning about emotions and social
applications. Parents can be very helpful in working with NVLD
children as long as additional support is provided. Another method
that has been helpful is that of peer or adult coaching. These
interventions will be briefly discussed below.
Parent Interventions
Parent Effectiveness Training (PET) (Gordan,
2006) is a program that assists a
child to manage his/her relations with others. PET encourages
parents to invite children over to play with their child in a
structured environment as well as join groups such as 4-H, Cub/Boy
Scouts or Brownies/Girl Scouts. The structure of these programs and
the emphasis on working together can assist a child with NVLD to
enter into more structured, safe settings for social experiences.
For parents who also experience social difficulties, family therapy
may be the most appropriate mechanism to support the child with
similar social difficulties. A frequent clinical observation is
that parents with children with NVLD (or ASD) may also experience
difficulties with social interactions. Thus, an intervention that
expects them to teach the child such skills is problematic.
While parents may not be the best vehicle for
teaching social skills, they are very helpful in providing
appropriate information about development, new programs, and the
child’s progress (Semrud-Clikeman & Schaefer, 2000). Parents supplied with suggestions and
support can provide additional experiences for their child that is
more helpful. Children with NVLD often experience rejection and
isolation in school and in unstructured activities. A parent who
can provide support through organized activities, a calm demeanor,
and a place to decompress is likely giving the best support to the
child. Setting up situations where the child is paired with one
other child who may be more tolerant of the child’s behaviors can
also help. Trips to the museum, movies, or a structured activity
are proactive for appropriate social exchanges. Situations that
don’t provide such structure are likely to be more
anxiety-producing and possibly less constructive as the child seeks
to entertain his/her “friend” (Glass, Guli, & Semrud-Clikeman,
2000; Semrud-Clikeman &
Schaefer, 2000).
Coaching
Matching the child with NVLD to a child who is
more tolerant for socialization can be helpful. While this type of
“friend making” can be somewhat artificial and requires a very
special child to support the child with NVLD, it can provide a safe
environment in which the child is able to perform skills that have
been taught in the clinic or in small groups. The advantages of
peer matching are that it occurs in a naturalistic setting and the
child learns from a same-aged child. However, it is time consuming
and requires a great deal of adult support for success both from
the parent and teacher. It may be most successful for children who
are in special education programs where there are additional
paraprofessionals and support rather than in a larger
classroom.
Suggestions in the field have been made for
coaching interventions. These interventions occur in the child’s
environment and the adult observes the child. Following the
observation, the child meets with his/her coach and discusses the
behaviors seen and the situations. Corrective exercises are
provided. It is likely that this method could be quite useful in
assisting the child to learn appropriate behaviors in a
naturalistic setting. This type of intervention does not have
empirical validation and can be costly. However, it may also be
helpful for children who are really struggling to relate to other
children.
Social Competence Intervention Program
A social competence intervention program (SCIP)
designed to work with children with NVLD and Asperger’s Disorder
has been developed (Guli, Wilkinson, & Semrud-Clikeman, 2008).
SCIP is an intervention that is multisensory in nature and targets
underlying difficulties in social perception as well as provide
exercises to improve the generation of strategies for problem
solving. Figure 12.1 illustrates the basic tenet behind this
intervention.

Fig.
12.1
Model for Social Perception
In SCIP, exercises were adapted from children’s
creative drama and theater classes to practice the processes
fundamental to social competence. These activities were originally
designed to help actors develop accurate perception and response to
cues, and address various aspects of social perception (Guli et
al., 2008). These activities fall into the following categories:
sensory games, space/movement games, mirroring activities,
communication with sounds, physical control, “part of a whole” and
multiple-stimulus games.
The exercises are designed to move from learning
how to perceive various emotions to appropriate interpretation of
these emotions and then to assisting with choosing the best
response to the situation at hand. In each case the training begins
with easily recognized emotions such as happy and sad, and moves to
more abstract emotions such as embarrassment, confusion, and
frustration. The initial session includes direct teaching of facial
expression recognition as well as voice intonation, intent of the
speaker, and interpreting body language. As the child moves through
the program, role-playing is introduced and the child is exposed to
more and more complex situations with significant amounts of adult
guidance. The SCIP program provides new experiences that change
with time, but are built on situations that are familiar and thus
not as anxiety-producing as fully novel experiences would be. The
work is constantly reviewed and supported throughout the
intervention, thus reviewing and refreshing skills.
One of the difficulties that children with NVLD
face is limited exposure to other children to practice skills. They
are often isolated and ignored. The intensity of the SCIP program
allows the child to experience being with other children as they
work toward a common goal; namely, understanding social
interactions. The experience of children with SCIP has been a
joining together and enjoyment of one another within a safe
environment. Activities and role-plays are in a setting which
allows the child to experiment, laugh when something goes wrong,
and find out that he/she is not the only one struggling with some
issues.
Guli et al., (2008) evaluated the efficacy of the
SCIP program. A treatment group and a clinical control group with
deficits in social perception were compared using several outcome
measures before and after participation in the SCIP program. The
outcome measures included a test of recognizing facial expressions
and voice cues, parent ratings on behavioral checklists of
withdrawal and social skills, and direct behavioral observations of
peer interactions. Following the intervention, parents and children
in the treatment group were interviewed about their
experiences.
Quantitative and qualitative support was found.
Improvement was found in the child’s ability to correctly recognize
facial expressions, vocal cues, and social behavior. Approximately
three-fourths of the parents reported positive changes in one
aspect of their child’s social functioning, while 82 percent
reported several aspects showed improvement. Moreover, these
findings strongly support research that stresses training in
perception and integration of nonverbal cues for children with
nonverbal learning disabilities (Barnhill, Tapscott, Tebbgenkamp,
& Smith, 2002; Bauminger,
2002).
Summary and Comments about NVLD
Emerging research underscores the need to
understand the dynamic interaction between psychological and
emotional problems in light of neuropsychological assets/deficits
in children with learning disabilities. Although further research
is necessary to verify these relationships and to determine how
learning disabilities change over the ages, an integrated
neurodevelopmental model provides the framework for such study.
Although Rourke has developed a model based on a series of related
studies spanning two decades, sub-typology research has been
criticized. Reynolds (2003)
asserts that models relying on profile analysis must take into
account the reliability (i.e., stability) of profiles. The extent
to which profiles change over time and how these changes might
affect the original clinical decision need further study. Others
have pointed out weaknesses in using correlational methods to imply
similarity among subjects (Keith, 2006). Correlational methods are also
inappropriate for studies when the linearity of variables is
questionable.
Despite criticisms of subtype research, Rourke's
NVLD model provides a foundation for further research and
contributes to our preliminary understanding of how
neuropsychological, cognitive, and social-emotional functioning
interacts with and influences the development of children. This
model describes a complex interaction among deficient and intact
neuropsychological systems, early experiences, and learning that is
associated with social-emotional functioning. Rourke does provide a
viable model for a “right-hemisphere syndrome” that can be tested
empirically with children experiencing academic disabilities
(primarily in math) and psychosocial adjustment difficulties using
standard neuropsychological and psychological tests.
Recent research indicates that the original
belief that motor and tactile issues were primary in NVLD have not
been supported and that attention and social-emotional functioning
may be important aspects of this disorder. The research does not
clarify the main aspects of NVLD or the neural underlays for the
difficulty these children have in relating to others in
visual-spatial skills and in executive functioning. In addition,
when the diagnosis is not clearly defined, it is difficult to
compare results across studies. Further validation of the disorder,
as well as additional study of the possible causes and
interventions, would be increase our understanding of this
disorder.
Case Study of a Child with Severe Developmental Dyslexia
The following case describes an assessment of a
10-year-old boy who had received excellent special education
services for several years, but who continued to be unable to read
beyond a primer level. The case demonstrates the need to evaluate
reading difficulties comprehensively, and obtain a family history.
Allen is a fourth-grade boy who was referred to the clinic for
ongoing reading difficulties despite having had three years of
special education services. He had been diagnosed with ADHD and
responded favorably to Ritalin. In kindergarten, Allen was first
identified as experiencing difficulty with readiness skills. He was
very active and had great difficulty staying in a group and
participating in activities. He started taking Ritalin in first
grade and was kept in first grade an additional year because of
significant delays in academics. Allen was evaluated in second
grade and placed in a learning disability program. Behaviorally and
socially he was reported not to experience any difficulties, and
was well accepted by his peers. He was also reported to be hard
working and motivated.
Allen was the product of a normal full-term
birth, labor, and delivery. Developmental milestones were generally
attained within normal limits for age. At an early age Allen was
noted to display an extreme level of overactivity and inattention.
He was diagnosed with ADHD in first grade. His Ritalin dosage has
gradually increased from 5 milligrams (mg) twice per day to a
current dose of 20 mg in the morning, 20 mg at noon, and
15 mg at 3:00 P.M. His paternal history is remarkable for
reading difficulties. His father, his stepsister, a paternal uncle,
and a grandfather have all experienced significant reading
difficulties, which continued throughout school and into adulthood.
Although Allen's father's intelligence is above average, he is
unable to read and is currently employed as a grocery stocker.
Allen's neurological examination and MRI were normal. He has not
had any head injuries, seizures, or serious illnesses.
Cognitive Ability
Allen’s evaluation indicated an average ability
with strengths in vocabulary, social comprehension, perceptual
organization and nonverbal reasoning. Significant weakness was
present in working memory as well as in memory for previously
learned material, abstract language ability, motor speed, and
arithmetic reasoning. The following results were obtained on the
WISC IV.
Verbal Comprehension
|
82
|
Perceptual Reasoning
|
99
|
Full Scale IQ
|
94
|
Working Memory
|
78
|
Processing Speed
|
75
|
Information
|
5
|
Picture Completion
|
10
|
Similarities
|
6
|
Coding
|
4
|
Arithmetic
|
5
|
Matrix Reasoning
|
10
|
Vocabulary
|
9
|
Block Design
|
8
|
Comprehension
|
10
|
Object Assembly
|
9
|
Digit Span
|
4
|
Symbol Search
|
6
|
Achievement Testing
Achievement testing indicated severe deficits in
all areas of reading, with math skills also depressed, particularly
in applied problems. The Woodcock Johnson Achievement Battery-III
was administered and the following scores obtained:
Letter-Word ID
|
46
|
Reading Comprehension
|
64
|
Reading Fluency
|
50
|
Word Attack
|
51
|
Applied Problems
|
75
|
Arithmetic Calculation
|
83
|
Math Fluency
|
80
|
Spelling
|
50
|
Written Expression
|
65
|
Writing Fluency
|
60
|
Allen is a choppy and dysfluent reader. He
appeared unsure of vowel and consonant sounds and consequently
relied on a “best guess” strategy for reading (e.g., using a word's
visual characteristics as an aid to decoding). The Lindamood
Auditory Concepts test was also administered to further evaluate
Allen's word attack skills. Allen performed at the mid-first grade
level on this test, with significant difficulties with sound-symbol
relationships even at the individual phoneme levels. Blending and
the ability to combine sounds were delayed. Allen experienced
difficulty at the primary level for distinguishing similar, but
different sounds at the beginning and ending of words.
Memory
Allen’s memory skills were evaluated using the
Children's Version of the California Verbal Learning Test.
Allen's learning of List A fell significantly
below average over the five trials. Although the learning curve
rose steadily over the five trials, suggesting that Allen benefited
from repetition of the words, the number of items recalled after
each trial fell below expectations compared to same-aged peers.
Allen's recall of List B also fell below average. Both short-term
free recall and cued recall fell within average levels for his age.
These findings indicate that Allen is able to retain information
that he has learned. His memory skills are problematic in that
Allen has difficulty encoding new information. In addition, he was
unable to utilize memory strategies that would assist him in
encoding information; rather he tried to recall the words using
rote memory rather than grouping them into categories.
Total Recalled
|
85
|
Trial 1 Recall
|
60
|
Trial 5 Recall
|
80
|
List B
|
75
|
Short-term Free Recall
|
100
|
Short-term Cued Recall
|
98
|
Long-term Free Recall
|
102
|
Long-term Cued Recall
|
103
|
Learning slope
|
88
|
Language Ability
Language assessment indicated that Allen has
difficulty in both receptive and expressive language skills. The
Clinical Evaluation of Language Fundamentals-3 was administered,
and the following results were obtained:
Receptive
Language
|
Expressive
Language
|
||
---|---|---|---|
Concepts and Directions
|
4
|
Formulated Sentences
|
5
|
Word Classes
|
9
|
Recalling Sentences
|
7
|
Semantic Relationships
|
3
|
Sentence Assembly
|
6
|
This assessment indicated pervasive language
problems in Allen's ability to understand and use language. On
receptive language tasks, Allen's ability to follow directions
using visual cues that increase in complexity was quite poor, and
likely a reflection of his previously identified difficulty with
adequately encoding verbally based information. Allen's performance
on a task that tapped his understanding of comparative, temporal,
quantitative, and spatial concepts in language also fell
significantly below average. Allen's ability to see relationships
between words was within age expectations.
On the expressive language measures, Allen
demonstrated significant weakness on a series of structured tasks
that required him to create sentences about pictures using stimulus
words. He had difficulty integrating words into a relevant sentence
while maintaining appropriate grammatical structure. Consistent
with his difficulties with encoding verbally mediated information,
Allen evidenced a significant weakness in his ability to repeat
progressively longer and syntactically complex sentences.
Attention
The Test of Variables of Attention (TOVA) was
used to measure attentional functioning. Testing was done off
Ritalin, on 15 mg of Ritalin, and on 20 mg of Ritalin.
Measures of vigilance (omissions), impulsivity and inhibition of
responding (commission), speed of information processing (reaction
times), and variability of reaction time (variability) were
obtained with the following results:
Measure
|
20 mg
|
15 mg
|
Off
Ritalin
|
---|---|---|---|
Omissions
|
98
|
98
|
66
|
Commissions
|
90
|
90
|
98
|
Response Time
|
67
|
54
|
34
|
Variability
|
63
|
26
|
< 25
|
Results indicated that on his current 20 mg
dose, Allen demonstrated age-appropriate gross attention to task
and impulse control. In contrast, reaction time and sustained
attention fell significantly below expected limits for age. On a
15 mg dose of Ritalin, Allen's gross attention and impulse
control were identical to that observed on the higher dose.
However, his reaction time and sustained attention were much poorer
on the lower dose of Ritalin. With the exception of his impulse
control, Allen's performance on the TOVA off medication fell
significantly below average on all attentional parameters. Overall
results indicated that Allen exhibits a beneficial response to his
current Ritalin dose of 20 mg. Even with the higher dose,
however, his response time and ability to sustain and deploy
attention consistently fell significantly below average.
Executive Functioning
Allen completed subtests from the Delis Kaplan
Test of Executive Functioning (D-KEFS). The D-KEFS found that
Allen’s executive functioning ability fell within the average to
far below average range. Allen’s visual-spatial-motor skills
consistently fell in the average range. For example, on a measure
that required Allen to connect a series of letters as quickly as
possible, his performance fell in the average range. On a similar
task, his ability to connect a series of numbers also fell in the
average range. He also performed in the average range when asked to
sequence between a number and a letter in succession (1-A, 2-B,
3-C, etc). On a measure of verbal fluency, Allen’s ability to
rapidly name as many words that began with a certain letter, name
as many animals, and as many male names as he could in 60 seconds
fell within the average range. His ability to repeat a sequence of
numbers presented orally fell within the low average range and his
ability to repeat a series of numbers and letters was also within
the low average range. Allen struggled in a task that required him
to rapidly name colors and color word names. His ability to name
colors and read color words fell in the average range. However, as
the task became more difficult, he struggled when he was asked to
name the color of a color word printed in an opposing color (Saying
“green” when looking at the word blue printed in green ink). His
performance in this response interference task fell in the far
below average range. Allen performed in the far below average range
on a planning task that required him to plan a set of sequential
moves using up to five rings in a predetermined starting point
after being shown the correct ending position of the rings.
Taken together these findings indicate that Allen
shows relatively better performance on visual-spatial-motor tasks
than tasks that require cognitive response interference, set
switching, and planning. This finding may mean that since he
performed in the average range on visual-motor tasks but not purely
cognitive executive measures, Allen may be experiencing specific
difficulty with tasks that require him to hold a cognitive task
“online” while ignoring distracters. In addition he experiences
problems in his ability to successfully plan and execute a set of
moves while remembering the directions necessary to complete the
task.
Visual-Spatial Skills
Allen's visual-motor integration skills were
assessed using the Developmental Test of Visual-Motor Integration.
Consistent with teacher reports regarding illegible writing and
poor copying skills, Allen's reproductions on this task fell
moderately below age expectations (standard scores = 76). On the
Judgement of Line Orientation, Allen showed below age level
functioning. His finger dexterity as measured by the Purdue
Pegboard was within age expectations for either hand and for both
hands together. These findings indicate some difficulty with
visual-spatial integration, but not with motor skills.
Behavioral/Emotional Functioning
Personality and behavioral assessment indicated
no areas of concern. He did not score in the significant range on
any portion of the Behavior Assessment Scale for Children II.
Teacher reports indicated concerns only in the area of academic
progress. These profiles indicated that Allen is perceived as well
adjusted, without any behavioral problems.
Summary and Recommendations
Allen is a 10-year-old boy with speech and
language problems as well as difficulty with acquiring reading
skills. He also has a history of ADHD and is currently being
treated with Ritalin. This evaluation was requested by his mother
to determine current reading skills and to offer treatment
recommendations. Assessment of Allen's academic achievement
confirms school and parental reports that he is experiencing
persistent and severe difficulties in acquisition of beginning
reading skills. Evaluation revealed that his reading skills fell
significantly below average, and well below what was to be expected
on the basis of his intellectual profile. Allen's reading skills
fall approximately at a mid-first grade level and are limited to
inconsistent identification of high frequency sight words. He shows
little in the way of word attack skills and is deficient in other
phonological coding skills that have been found to be highly
related to the normal acquisition of reading. Relative to an
assessment completed more than two years ago, Allen shows little
progress. Overall, results from the present testing indicate the
presence of a verbally based learning disability. Testing of
language functions revealed striking weaknesses in both receptive
and expressive language skills. Although parental reports indicated
that Allen has made a stable pattern of gains since speech therapy
was initiated this year; his language problems are of such severity
that they are continuing to have an impact on his ability to use
and understand language effectively. Testing of memory and learning
indicated that Allen experienced difficulties in encoding and
memorizing verbal information, such as stories and lists of words.
Allen's ability to remember verbal information is constrained by
problems with encoding and inputting. He does not have difficulty
in retrieving and outputting information from memory; that is, once
information is encoded into memory, he can retain it for relatively
long periods of time. His encoding problems also affect his ability
to process verbal material, such as instructions, adequately. It is
important to emphasize that despite his encoding difficulties,
Allen has the potential to learn and memorize new information, but
he will do so at a rate that is significantly slower than his
same-aged peers, and he will require more than the usual amount of
repetition. Allen does not appear to have significant difficulty
memorizing material that is visual in nature, such as designs and
pictures. Recommendations include an intensive learning
disabilities program to work on his phonological coding
difficulties while simultaneously strengthening his sight word
vocabulary. Given Allen's good visual-perceptual and visual-memory
abilities, it is recommended that teaching strategies focus on a
sight word approach with the high frequency words he encounters.
For Allen to become a fully functional reader, it is crucial that
he become adept at decoding unknown words. Teaching Allen how to
decode words will not be an easy task, given that he lacks a number
of the essential phonological processing skills necessary for
effective decoding. To help Allen develop the phonological
processing skills that are critical to becoming an effective
reader, the Lindamood Auditory Discrimination In Depth Program is
recommended. This program, multisensory in nature, recognizes that
some children have great difficulty in recognizing and perceiving
the association between sequences of sounds in spoken words and
sequences of letters in written words. It provides experience at a
level prior to that of most beginning phonic programs by teaching
sound-symbol correspondences through activities that allow students
to hear, see, and feel sound units of language. The program starts
with oral motor activities (e.g., noting the position of the mouth
and tongue when a certain sound is produced), and gradually builds
up to working with words. For the program to be effective for
Allen, it should be intensively incorporated into his reading
program. For many children with phonological processing
difficulties, this program has been helpful in diminishing their
decoding difficulties. The Lindamood Program, including the
associated manual and step-by-step program instructions, can be
obtained through Riverside Press.
It is further recommended that Allen be provided
with a computer for rehearsing reading skills. Moreover, a language
experience approach should be incorporated into Allen's classroom
program. This method, which will encourage Allen to use his own
words, includes writing his own book by dictating a story to a
teacher or aide who provides him with a written transcript. Allen
would then read the story back and accumulate flashcards of unknown
words that he encounters. Taped books should also be available for
Allen. The benefits of taped books are two-fold. They will assist
with the acquisition of information that would ordinarily be
available only through written text, and provide a way to enhance
Allen's reading skills by allowing him to listen to a tape as he
follows along in a book. Language therapy is also required to
assist with his skill development. Intervention that focuses on his
organization of language output, pragmatics, and repair strategies
(e.g., using an alternative word or phrase to accommodate his word
finding difficulty), will be especially helpful to him at this
point. These recommendations have been put into place. Allen will
return to the clinic in approximately six months to assess his
progress.
Chapter Summary
The purpose of this chapter was to describe the
neuropsychology of language disorders and learning disabilities in
children. In all these disorders, the child's genetic inheritance
and neurological makeup interact with the environment. A child with
language and learning disorders is born with neurological
constraints that make up the beginning points of the child's
interaction with the world. In these disorders, early interventions
that combine phonological awareness training and direct instruction
of the child in the context of reading have been most successful.
The neurobiological constraints are the backdrop for what develops
and, although they are limiting in some manner, they are also
malleable through environmental interventions.
A transactional approach allows for a
simultaneous understanding of the biology, neuropsychology, and
family systems of children with neurodevelopmental disorders. Such
an understanding is imperative in order to work effectively with
children with neurobiological vulnerabilities. As one parent of a
learning disabled child reminded the first author: “You
professionals give us [the mother and father] lots of
suggestions-do you not recognize that we also have learning
disabilities? How do you expect us to follow through when we have
the same problem?” The wisdom of this father's statement cannot be
lost on us as we work with families of children with
neurodevelopmental disorders. Families frequently share, to some
degree at least, the problems of their child. Even when they do
not, the stress, concern, frustration, and disappointment families
routinely feel is often ignored when developing treatment plans for
children and adolescents with disorders. These contextual variables
also need to be assessed and planned for in effective
interventions.
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