February 25, 2011

The Syndrome of Nonverbal Learning Disabilities - Clinical Description and Applied Aspects

Michael A. Roman
The University of Texas

Abstract

The syndrome of nonverbal learning disabilities is now well recognized in the field of neuropsychology. However, many psychologists in other specialties are unfamiliar with this disorder. This paper presents a clinical description of the syndrome based on a review of the relevant literature. The relevance of this disorder in educational settings is emphasized. Applied recommendations for evaluation, diagnosis, and treatment are offered. In addition, a clinical case example, along with supporting evaluation data, is provided.


Citation Information

Roman, M. (1998, November 18). The syndrome of nonverbal learning disabilities:
Clinical description and applied aspects. The Digital Enquirer Online.
Available: http://digitalenquirer.blogspot.com/.



Introduction


The syndrome of nonverbal learning disabilities (NVLD) includes a number of specific, potentially debilitating symptoms. Rourke (1995a) has grouped these into three major areas: neuropsychological deficits, academic deficits, and social-emotional/adaptational deficits. Neuropsychological deficits include difficulties with tactile and visual perception, psychomotor coordination, tactile and visual attention, nonverbal memory, reasoning, executive functions, and specific aspects of speech and language. Deficits in math calculations, mathematical
reasoning, reading comprehension, specific aspects of written language, and handwriting are primary academic concerns. Social deficits include problems with social perception and social interaction. Children with this disorder are also seen as having substantially increased risk for internalized forms of psychopathology, primarily anxiety and depression. There has also been evidence to suggest a greater risk for suicide (Rourke, Young, & Leenaars, 1989).

The NVLD syndrome has been described as a distinct diagnostic entity only recently. The foremost researcher in the area is Byron Rourke, although many other individuals have been intimately involved with investigating and treating this disorder (e.g., Fletcher et al., 1992; Johnson & Myklebust, 1967). Perhaps the first written descriptions of the syndrome were prepared by Johnson and Myklebust, although there is no reason to believe the disorder is new.

Nonverbal learning disabilities represent a discrete and separate diagnostic entity. However, some of the symptoms identified are similar to those described for other disorders. Individuals with right hemisphere dysfunction (Semrud-Clikeman  & Hynd, 1990; Weintraub & Mesulam, 1983), Asperger's syndrome (Klin, Sparrow, Volkmar, Cicchetti, & Rourke, 1995; Semrud-Clikeman & Hynd, 1990; Wing, 1981), and "central processing disorders" (Rourke, 1982) each possess a number of symptoms that overlap with those seen in NVLD. Nevertheless, these disorders can be differentiated through proper assessment.

For example, right hemisphere dysfunction may produce a number of specific deficits not seen in the typical NVLD presentation (Ardila & Ostrosky-Solis, 1984). These may include more severe speech prosody deficits, more pronounced deficits with planning and organization, and more severe tactile-spatial deficits.
Separate theoretical developmental models have emerged that emphasize the role of the right cerebral hemisphere (Goldberg & Costa, 1981) versus the role of subcortical white matter systems (Rourke, 1987) to explain deficits common to both conditions. Overall, however, these models may be more complementary rather than contradictory in that they both yield accurate predictions regarding deficits under somewhat different circumstances (Rourke, 1995).

Some clinicians have also suggested that Asperger's syndrome and NVLD are similar disorders. This is a controversial assertion. Many researchers have questioned the validity of Asperger's syndrome as a distinct diagnostic entity apart from autism (Semrud-Clikeman & Hynd, 1990; Wing, 1991). In essence, the lower functioning children diagnosed with Asperger's may be more properly diagnosed as autistic. In turn, many of the higher functioning children diagnosed with Asperger's syndrome may instead be children with NVLD who have been misdiagnosed.

While the NVLD syndrome has only recently been described in detail (Rourke, 1987, 1989), a number of important articles and two major books have been dedicated to descriptions of the disorder (Rourke, 1989, 1995a). Despite this fact, the syndrome is unfamiliar to many psychologists, diagnosticians, and educators.
There is no formal provision under federal special education law recognizing the existence of nonverbal learning disability as a handicapping condition. In most cases, children with this disorder are best classified as Other Health Impaired. Because they may also have specific motor skills deficits, problems with math, social interactional difficulties, and/or emotional disturbances, some of these children may also be appropriately classified as orthopedically handicapped, learning disabled, or emotionally disturbed. This may be particularly
appropriate for cases of neurologically acquired NVLD rather than the more common developmental cases of the disorder.

The purpose of this article is to familiarize the reader with the NVLD syndrome and the current state of research on this disorder. Practical guidelines for identifying children at risk, evaluating and diagnosing the syndrome, and making treatment recommendations are emphasized. Finally, a case example with accompanying test data illustrations is provided.

Clinical Description of the Syndrome

Children with NVLD present with a wide range of visual-spatial, visual motor,
sensory, and motor deficits. At the more basic levels, these deficits involve
problems with visual and tactile perception and discrimination. In general,
children with this disorder demonstrate increasing difficulty as the spatial
aspects of the task increase. For example, they may be relatively capable of
simple visual discrimination tasks requiring them to find shapes that are similar
to or different from a target shape. The visual
discrimination subtest from the Test of Visual Perceptual Skills - Revised
(TVPS-R; Gardner, 1996) is one example of this. In
contrast, they are likely to have extreme difficulty with tasks requiring them
to find embedded figures (e.g., visual figure-ground on
the TVPS-R) or determine the spatial orientation of lines (e.g., Judgment
of Line Orientation Test, Benton, Hamsher, Varney, & Spreen, 1983). They
are also likely to demonstrate difficulty with tactile perception and tactile
discrimination. Examples of these types of impairment can be found on haptic
discrimination tasks and other specific neuropsychological tasks, such as Tactile
Form Recognition or Fingertip Number Writing from the Halstead-Reitan Neuropsychological
Test Battery (Reitan, 1979).


Such children are often described as better "auditory learners" than "visual
learners." This is related to their greater proficiency with verbal-auditory
modalities than tactile-visual modalities (Rourke, 1995a). In addition, they
are frequently described as less active and more reluctant to physically explore
their environment (Rourke, 1989). This lack of active exploration is believed
to be secondary to their lack of proficiency with tactile and visual input (Rourke,
1995a). In effect, because they frequently gain little useful information from
manipulating their environment, they seldom do so on their own initiative.
Rourke (1989) provided the first detailed description of the nonverbal learning
disability syndrome based on his research into learning disability subtypes
(Rourke & Fisk, 1988). More recently (Rourke, 1995a), refined and expanded his
description of NVLD symptoms. His model is dynamic in speculating that primary
neuropsychological deficits lead to secondary deficits in modality-specific
aspects of attention and, more generally, in the extent to which children actively
explore their environment. These primary neuropsychological deficits include
tactile perception, visual perception, and motor coordination. In turn, these
secondary deficits lead to tertiary deficits, particularly in nonverbal memory,
abstract reasoning, executive functions, and specific aspects of speech and
language. Specific, measurable impairments in academic performance, social functioning,
and emotional well being are direct by-products of this constellation of primary,
secondary, and tertiary neuropsychological deficits.

Rourke (1995a) also described a number of assets in children with NVLD. These
abilities typically measure within the average to above average range relative
to normal peers. These strengths include simple motor skills, auditory perception,
simple auditory attention, and rote memory for simple verbal material. Language
strengths include adequate receptive language, adequate simple verbal expression,
and good phonetic analysis. The relative strengths with phonetic analysis demonstrated
by children with NVLD frequently lead to good single word recognition and strong
spelling skills, particularly for phonetically predictable words. However, they
often have difficulty with spelling and decoding phonetically unpredictable
sight words.

Cognitive and Neuropsychological Performance Issues

A number of specific cognitive and neuropsychological difficulties are readily
apparent in children with NVLD. As with any specific syndrome, the accuracy
of the diagnosis is directly proportional to the number and magnitude of symptoms
present that are consistent with the diagnosis. Some global definitions are
in order.

"Cognitive," as used in this context, refers to an individual's abilities rather
than to specific acquired skills. This distinction between abilities and skills
is an important one. When a cognitive deficit is present, it is reasonable to
expect that all skills dependent on that cognitive ability will be hindered
to at least some degree. Of course, all measures of ability are at least in
part related to the measurement of acquired skills (Anastasi, 1988). For example,
the concept of intelligence is a completely valid ability-based construct (e.g.,
Brody & Brody, 1976; Mattarazzo, 1972). However, all intelligence tests rely
on the measurement of acquired skills and knowledge to make inferences regarding
underlying ability. Nevertheless, when a cognitive deficit is truly present,
difficulties should be expected on all measures requiring skills dependent on
that particular cognitive ability. This is similar to the distinction between
production deficits vs. mediational deficits as described by Flavell (1970).
"Neuropsychological" refers to both simple and complex cognitive abilities
that can be directly or indirectly linked to the integrity of cerebral functioning.
The goal of neuropsychological evaluation is to investigate discrete cognitive
processes involved in acquiring new information. For example, poor performance
on a measure of copying, such as the Developmental Test of Visual-Motor Integration
(Beery, 1982), assuming adequate effort has been put forth by the test taker,
may be due to any of a number of factors. Problems with visual perception, motor
execution, spatial planning, or the integration of visual and motor abilities
may result in poor copying of geometric figures. It is the goal of a comprehensive
neuropsychological evaluation to attempt to determine which of these factors
are involved. Therefore, neuropsychological does not refer to any specific test
or set of tests, but rather to a way of thinking about and investigating cognitive
functions. In some cases, this may also involve making inferences about the
integrity of cortical or subcortical brain regions that subserve specific cognitive
processes.

Intellectual functioning

One of the most readily obvious identifying features of NVLD is a significantly
higher Verbal IQ score than Performance IQ score on formal measures of intelligence
(Johnson, 1987; Weintraub & Mesulam, 1983). This finding is a direct result
of the expected discrepancy between verbal, language-based cognitive abilities
and nonverbal, visual-spatial cognitive abilities in these children. In general,
the greater the magnitude of this discrepancy, the more likely the accuracy
of the diagnosis. Of course, Verbal-Performance IQ score discrepancies alone
are never diagnostic in the absence of other supporting evidence. Because neither
Verbal IQ scores nor Performance IQ scores are "pure" measures of ability, discrepancies
between the Verbal Comprehension Index and the Perceptual Organizational Index
are frequently better and more stable measures (Kaufman, 1979). A discrepancy
of as few as 10 points may be supportive if there is substantial evidence of
the disorder in other domains. More typically, a VIQ-PIQ discrepancy of 15 points
or more is expected. It is not unusual to find differences of 40 points or more
between Verbal and Performance IQ scores in more severely affected individuals
(Johnson, 1987).

Executive functions and higher level reasoning

Rourke (1995a) has also identified deficits in executive functioning as among
the primary impairments in NVLD (Strang & Rourke, 1983). Executive functions
include such higher level abilities as abstract reasoning, logical analysis,
hypothesis testing, and cognitive flexibility, or the ability to "shift gears"
mentally. The ability to focus, shift, and distribute attention, organize information
into memory to aid learning and remembering, and otherwise regulate thought
processes are also examples of executive functions. Although similar etiologies
have been proposed to explain both nonverbal learning disability and executive
dysfunction (i.e., impairments of subcortical white matter), poor performance
on measures of executive functioning are not always found in children with NVLD.
There is no clear data to indicate how frequently executive functioning deficits
occur in the NVLD population. It is the author's experience that such deficits
are common in more severe cases of NVLD and quite rare in more subtle cases.
Many measures of executive functioning exist. Some of the more commonly administered
measures include the Wisconsin Card Sorting Test (Berg, 1948), the Category
Test (Reitan, 1979), the Tower of London (Shallice, 1982), the Trail Making
Test (Reitan, 1979), and the Progressive Figures and Color Form Tests (Reitan
& Wolfson, 1985). In addition, many tests of attention and working memory could
appropriately be considered measures of executive functioning (Pennington, 1994).


Memory functions

Significant discrepancies between verbal and nonverbal memory are also frequently
observed. As with other nonverbal functions, NVLD children frequently demonstrate
greater impairments on nonverbal memory tasks as the spatial component of the
task increases. For example, it is typical to find poorer performance on the
Design Memory subtest than the Picture Memory subtest of the Wide Range Assessment
of Memory and Learning (WRAML; Sheslow & Adams, 1990). On more simple nonverbal
tasks, or those that are more readily verbally encoded, deficits in performance
may not appear. For example, both the Visual Memory subtest and the Visual-Sequential
Memory subtest of the Test of Visual Perceptual Skills - Revised (Gardner, 1996)
frequently score within the average range, particularly for older children.
In addition, NVLD children frequently demonstrate problems with more complex
measures of verbal learning and memory (Fletcher et al., 1992). This finding
is consistent with Rourke's prediction that strengths in verbal learning and
memory are largely confined to simple, rote tasks (Rourke, 1995a).
Deficits in executive functions, including working memory, are hypothesized
to be responsible for these difficulties on more complex verbal memory measures
(Rourke, 1995a). Of course, it is reasonable to expect that NVLD children that
do not demonstrate executive functioning deficits will be less likely to show
deficits on verbal memory measures. However, weaknesses in nonverbal memory
are still likely to be observed.

A good core memory battery for assessing the presence of nonverbal learning
disabilities might include the Verbal Selective Reminding Test or the California
Verbal Learning Test and selected subtests of the Wide Range Assessment of Memory
and Learning, particularly the Story Memory, Picture Memory, and Design Memory
subtests. For many children with this disorder, discrepancies can also be found
between auditory span of attention, as measured by a digit span test, and spatial
span of attention, as measured by the Finger Windows subtest of the WRAML or
Corsi blocks (Milner, 1971). In addition, many of these children demonstrate
a significantly poor backward digit span with a relatively better forward digit
span. The tendency of many children to mentally "visualize" the forward sequence
and then "read" it backwards frequently exceeds the NVLD child's capacity to
manipulate mental representations.
 

Language functions

Children with NVLD usually perform well on measures of receptive vocabulary
and expressive vocabulary. Some examples of common measures for receptive vocabulary
include The Peabody Picture Vocabulary Test (Dunn & Dunn, 1981) and the Receptive
One-Word Picture Vocabulary Test (Gardner, 1985). The Expressive One-Word Picture
Vocabulary Test - Revised (Gardner, 1990) and the Boston Naming Test (Kaplan,
Goodglass, & Weintraub, 1983) are among the best known measures of expressive
vocabulary. Among neuropsychologists, these expressive measures are sometimes
referred to as "confrontation naming" tasks.

NVLD children sometimes demonstrate weakness in particular aspects of speech
and language. As with right hemisphere damage individuals (Ryalls, Joanette,
& Feldman, 1987), difficulties with speech prosody and problems understanding
and/or expressing emotional intonation are frequently observed in the more severe
cases of NVLD. Difficulties with prosody often involve monotone speech with
little inflection. Because these children are often hyperverbal in social contexts,
their peers frequently see them as droning on relentlessly over boring topics.
The deficits these children demonstrate in nonverbal aspects of interaction
directly lead to an overreliance on verbalization as a primary means of social
interaction. Because the content of their speech is often simple and repetitive,
they frequently present as having a restricted range of interests, one of the
primary features of Pervasive Developmental Disorder. Difficulties with emotional
intonation and affective expression in speech can be measured by asking the
child to repeat a neutral phrase within different emotional contexts. For example,
they may be asked to state, "I'm going to the store," as if they were angry,
sad, or surprised. Similarly, their receptive understanding of the affective
tone of language can be assessed by having the examiner repeat this same neutral
phrase with different emotional inflections, then asking the child to label
the corresponding mood.

Visual-spatial abilities

As already noted, difficulties with visual perception, visual processing, and
visual-spatial cognitive abilities are the most prominent features in NVLD (Harnadek
& Rourke, 1994). These children frequently demonstrate more impairment on tasks
demanding a greater degree of visual processing or involving visual-spatial
demands. Measures such as the Judgment of Line Orientation Test are typically
very difficult for these children. They may frequently attempt to compensate
for these difficulties by employing ineffective strategies, such as attempting
to "measure" the angles separating the two lines on the target stimulus with
their fingers, then transferring this "measurement" to the response key to determine
the answer. Difficulties with copying block designs are also typical. In general,
these children have difficulty effectively matching to sample to aid copying,
demonstrating deficits in part to whole relationships. They typically have extreme
difficulty visualizing the overall gestalt of images, such as required on the
Object Assembly subtest of the Wechsler scales.

Problems with drawing or copying are frequently observed. In addition, handwriting
may often be poor, at least initially. There is some evidence that children
with NVLD are capable of mastering repetitive motor skills with repeated practice
over time, despite the fact that they may be particularly weak in acquiring
these skills initially. Handwriting, copying of simple shapes, cutting, coloring,
pasting, and simple drawing are examples of fine motor skills that frequently
improve with age.

One of the better and more dramatic measures for investigating NVLD is the
Tactual Performance Test (Reitan, 1979). This task requires the subject to place
blocks into a formboard while blindfolded. This measure is arguably the only
truly spatial measure in our assessment arsenal because it is performed without
the aid of visual input. Because children with NVLD have extreme difficulty
"building spatial maps," they frequently perform poorly on this task, often
demonstrating little to no learning (Harnadek & Rourke, 1994).

Sensory-perceptual and motor functioning

A number of motor and sensory-perceptual deficits have also been documented
in this disorder. Difficulties with tactile discrimination, haptic discrimination,
and fine motor coordination are typical. NVLD individuals often demonstrate
more difficulty with sensory and fine motor skills on the left side of the body
than the right. They almost always demonstrate difficulty with such tasks as
finger localization, fingertip number writing, tactile form recognition, and
fine motor speed and dexterity on measures such as the Grooved Pegboard Test
(Klove, 1963). However, measures of grip strength are usually normal and finger
tapping speed is frequently average or near average.

As noted above, children with NVLD are frequently able to achieve average or
near-average proficiency on a number of repetitive motor tasks, such as handwriting.
They are frequently less coordinated with regard to gross motor activity, particularly
when the development of specific skills is required. For example, they may not
have difficulty riding a bicycle, but may demonstrate significant difficulty
playing competitive sports. In general, these children are far less athletically
capable than their peers.

Educational and Academic Performance Issues

Classically, children with NVLD perform better on measures of word recognition
and spelling than math. The primary reason for this is that math is more dependent
on spatial and nonverbal concepts than is the case for either reading or spelling.
For example, one cannot understand the concept of fractions without some mental
representation of an object divided into pieces. Psychometrically, formal measures
such as the Wide Range Achievement Test (Wilkinson, 1993) frequently indicate
standard score discrepancies of one standard deviation or more between math
and reading and math and spelling.

Because these children frequently have adequate phonological abilities, they
may often be more successful at reading and spelling phonetically predictable
words than phonetically unpredictable words. This can sometimes result in a
failure to find the expected discrepancies between math and reading or math
and spelling on integrated tests such as the Wide Range Achievement Test, even
when the diagnosis of NVLD is appropriate. Using more sensitive measures, such
as the Woodcock-Johnson Tests of Achievement (Woodcock & Johnson, 1989), can
frequently assist the examiner in documenting the discrepancy. Children may
sometimes demonstrate better performance on the Word Attack subtest then the
Word Identification subtest. More sensitive measures of spelling, such as the
Test of Written Spelling - 3 (Larsen & Hammill, 1994) often yield notable discrepancies,
with higher standard scores obtained for phonetically predictable words than
phonetically unpredictable words.

Another classic finding is the discrepancy between content areas of academics
as opposed to more applied aspects. Content areas can be defined as the more
basic and mechanical aspects of an academic subject. These include word recognition
and word attack for reading; arithmetic calculations within math; and spelling,
grammar, and syntax within written language. In contrast, applied aspects of
academic subject areas include reading comprehension, math applications (including
word problems and algebra), and written composition.

With regard to NVLD children, reading decoding is frequently average while
reading comprehension is often poor. Math reasoning is often more impaired than
math calculations. They may have difficulty with word problems and almost always
struggle with algebra. Within the area of written language, spelling, vocabulary
usage, and sentence construction may be adequate. However, children and adults
with NVLD frequently have difficulty generating ideas. B. P. Rourke (personal
communication, September, 1991) indicated that college students with NVLD may
often produce lengthy term papers composed of well constructed sentences that
fail to make any substantive points. In this regard, their writing is often
"empty" and superficial. The same phenomena are also frequently observed in
their pragmatic language, particularly when they are pressed on a specific topic
of conversation. Problems with executive functions, integration and synthesis
of information, and generalization of knowledge are thought to underlie this
content versus applied discrepancy (Rourke, 1995a).

Social Performance Issues

One of the most debilitating practical features of the NVLD syndrome is the
extent of social impairments. Because much of social communication is nonverbal,
involving "body language," facial expressions, and tone of voice, individuals
with NVLD are at a significant disadvantage due to their impairments in visual
processing and visual-spatial perception. They tend to miss important cues in
social interaction and almost always fail to appreciate nuances in behavior
and the subtle cues they may convey. Their difficulties with understanding affective
intonation further impair their ability to benefit from verbal feedback. These
weaknesses lead to significant deficits in social perception.

Social judgment and social problem solving are also typically impaired. Some
of these impairments are a direct result of problems with perception. In effect,
when individuals are unable to accurately perceive a social situation, they
are at a significant disadvantage for choosing a correct response. Deficits
in reasoning and generalization of knowledge also directly contribute to disadvantages
in social problem solving. Furthermore, their behavioral response to similar
situations occurring over time may appear very inconsistent and even contradictory.
Interpersonal intimacy is frequently impaired, although problems forming close
personal attachments may not be noticed until late childhood or early adolescence
when dating begins. Rourke (1995a) speculated that these difficulties with establishing
intimacy are directly related to the lack of "tactile-perceptual and psychomotor
prowess required for smooth affectional encounters" (p. 17). Difficulty maintaining
meaningful friendships may also occur. As already noted, problems with speech
prosody and expressive language may lead to increased rejection by peers.
Another major characteristic of individuals with NVLD is a lack of adaptability
(Rourke, 1995a). In general, children, adolescents, and adults with this disorder
respond poorly to novel circumstances. The ability to deal with changing circumstances
is a fundamental aspect of social competency. It is also an important aspect
of normal social development. The difficulties with reasoning, flexibility,
and problem solving in NVLD individuals, combined with their other cognitive
deficits, place them at a substantial disadvantage for coping with the changing
circumstances of day-to-day life.

Emotional Issues

Many authors have indicated an increased risk of emotional disorders in individuals
with NVLD (Rourke, 1988; Rourke & Fisk, 1981; Rourke, Young, & Leenaars, 1989).
These individuals, as well as those with other evidence of right hemisphere
dysfunction (Weintraub & Mesulam, 1983), appear to be at risk for virtually
all types of emotional disorders ranging from adjustment problems to active
psychotic disorders. There is also evidence to suggest that, as a group, children
with NVLD are more susceptible to internalizing psychological disorders, such
as anxiety and depression, than children with other types of learning disorders
(Ozols & Rourke, 1985). Difficulties with socialization, problems maintaining
close interpersonal relationships, and the decreased likelihood of developing
intimate relationships significantly contribute to feelings of low self worth.
As a group, NVLD individuals have been found to be at increased risk for both
depression and suicide attempts relative to the normal population (Rourke, Young,
Strang, & Russell, 1986).

The lifelong difficulties with academic and social functioning most NVLD individuals
endure contribute directly to their problems with emotional adjustment. Some
of these difficulties with internalizing emotional problems can be demonstrated
in early childhood. However, problems with anxiety and depression are much more
common through adolescence and into adulthood. Rourke et al. (1989) indicated
that the frustrations many individuals with NVLD face culminate when they attempt
to enter the workforce. They rarely make good impressions during job interviews.
They are also more likely to demonstrate difficulties getting along with coworkers.
Visual-spatial difficulties and problems with reasoning and judgment make them
more accident prone and less successful in many occupations (Rourke et al.,
1989).

Developmental Course

One of the best articles describing the developmental course of the NVLD syndrome,
but rarely cited, was written by Johnson (1987). Johnson related that development
is frequently characterized by passivity with little exploration of the environment.
During infancy, NVLD children may be less interactive with adults and may show
less interest in both verbal and nonverbal stimuli. They are often described
as lacking exploratory play toward items such as rattles and crib mobiles. They
may also be less responsive to playful verbalizations from their caretakers.
As these children develop into later infancy and more advanced motor abilities
begin to emerge, they are often poorly coordinated. They may participate only
minimally during feeding and play times. Acquisition of simple self-help skills
is often delayed. Furthermore, once they begin to walk, they may appear clumsy
and are often more likely to bump into things or break objects around the house.
As Rourke (1995a) indicated, it is not unusual for these children to be labeled
as hyperactive or diagnosed with an Attention Deficit Hyperactivity Disorder
during the preschool and kindergarten years. Their poor social judgments can
often be interpreted as problems with impulsivity. Furthermore, the poor motor
coordination resulting from their tactile and visual-spatial deficits increases
the likelihood they will be identified as disruptive or destructive.
Difficulties with daily living skills related to eating, dressing, and simple
grooming may be noted. In particular, motor abilities necessary for dressing-such
as fastening fasteners and learning to tie shoes-are frequently impaired. The
acquisition of early preacademic skills related to coloring, cutting, and pasting
is also typically delayed. In many cases, these children show little to no interest
in working with puzzles, blocks, Legos, or other developmentally appropriate
materials. Unfortunately, it is the author's experience that it can be difficult
to obtain accurate information regarding a child's proficiency for building
puzzles and for working with blocks and other construction materials from parent
interviews. Sometimes parents will report that their children demonstrate normal
interest and proficiency in these types of tasks even when objective observers
would rate them poorly. Generally, parents are more reliable and accurate in
reporting levels of proficiency for dressing, cutting, coloring, and pasting.
NVLD children frequently demonstrate initial difficulties acquiring early academic
skills. Problems with letter and number recognition, difficulty with one-to-one
correspondence in counting, and problems with copying letters and numbers are
common. Printing and drawing also are frequently poor. With repeated practice,
most NVLD children develop normal proficiency with these types of tasks. Rourke
(1995a) suggested that these children eventually acquire normal or nearly normal
proficiency on these types of tasks regardless of whether or not they receive
early physical intervention such as occupational therapy. It is not unusual
to find a history of early involvement in occupational therapy and other related
services.

In the preschool and beginning elementary school years, children with NVLD
typically demonstrate difficulty getting math, reading, and writing "off the
ground." It is common for them to have difficulty acquiring recognition of letters
and numbers because of the inherent visual-spatial aspects involved in early
acquisition. With frequent practice, they become more successful at these tasks
and eventually profit from the development of the necessary symbol systems required
for the early development of reading and math concepts. As already noted, often
letter formation and handwriting are initially poor, but typically improve over
time.

In the early elementary school years, children with NVLD may demonstrate average
to above average academic performance. This is sometimes true as early as the
first grade, but is frequently seen in the second through fourth grade, particularly
for children with more minor forms of the disorder. Of course, those children
that are more severely affected may never demonstrate average levels of academic
proficiency. Unfortunately, as this more successful group of NVLD children progress
into middle school, particularly through the fifth through seventh grades, they
often begin to have difficulty maintaining their academic performance. For math
in particular, affected individuals rarely exceed a sixth grade equivalent,
even as adults (Rourke, 1995a). Difficulties with executive functioning, problem
solving, and memory for more complex and meaningful verbal and nonverbal material
make it difficult for them to maintain their prior levels of performance (Rourke,
1995a). The author has encountered more than one situation in which school personnel
have been reluctant to classify a NVLD child as learning-disabled in their middle
school or high school years, despite significant intellectual-achievement discrepancies,
because they did not demonstrate early academic deficiencies.

As already noted above, phonological awareness and the acquisition of phonics
often are strengths for NVLD children. They are typically far more proficient
in word recognition and spelling than in math. However, this discrepancy may
not be obvious until the fourth or fifth grade, largely because of the simple
nature of the math tasks that are presented to them. While they frequently have
difficulty rapidly retrieving math facts, particularly with regard to learning
the multiplication tables, normal variability between children in the earlier
grade school years makes it possible for NVLD children to still score within
the average gross range for math at this age. However, Rourke (1995a) indicated
that these children rarely exceed a fifth or sixth grade level of proficiency
in math. Difficulties with reading comprehension, thinking and reasoning, novel
problem solving, and written expression are frequently more obvious as these
children progress into the later elementary and middle school years.

Frequently, number of practical deficits emerge, particularly with regard to
math­based survival skills related to time, money, and measurement. These children
often have difficulty with the concept of time. This often applies to the calendar
as well as the clock. Learning to tell time is almost always difficult, particularly
on an analog clock. These children may have difficulties naming the days of
the week or months of the year in order, but typically succeed after much practice.
Problems with time management and scheduling may persist into adulthood. Their
ability to recognize and discriminate coins is often slow to develop. More fundamentally,
they have difficulty acquiring money concepts. These difficulties frequently
persist into adulthood and are manifest as difficulties with budgeting, balancing
a checkbook, making change, and doing comparison shopping. Difficulties with
measurement concepts are most obvious on tasks requiring estimation. Children
and adults with NVLD are often confused by systems and units of measurement
and may make outrageous estimations regarding size, distance, or quantity. They
may, for example, describe a basketball player as 20 feet tall, even if given
comparative information, such as the height of the basketball rim from the floor.

These outrageous estimations are particularly common for younger children who
manifest this disorder. Older children and adults with NVLD may manifest problems
with cooking and household management. Doubling and halving the size of a recipe
are examples of tasks that are particularly difficult for these individuals.

Because of their relatively stronger language-based abilities, it is not uncommon
for higher functioning NVLD individuals to complete college or even obtain a
masters degree. However, their difficulties with social skills and higher level
cognitive abilities frequently lead to frustration on the job or difficulty
finding employment. Problems with planning and organizational skills can further
impair their ability to functional well at home and on the job. Less than satisfactory
social relationships and difficulties with developing intimate relationships,
as already described above, can prove particularly frustrating. For these and
other reasons, symptoms of depression and anxiety are common (Rourke & Fisk,
1981; Rourke et al., 1989; Weintraub & Mesulam, 1983).

Prevalence and Incidence

No clear numbers are available regarding either the prevalence or incidence
of the nonverbal learning disability syndrome. In many respects, the disorder
has been too recently recognized to make accurate inferences regarding prevalence
and incidence. To date, no epidemiological studies have been undertaken. Other
problems include inconsistency in the definition of this disorder across researchers.
While several reports have made direct recommendations for the inclusion of
appropriate measures to evaluate this disorder (Harnadek & Rourke, 1994; Rourke,
1987), there remain differences of opinion regarding choice of an appropriate
test battery. Furthermore, as with all complex developmental disorders, there
is no formal consensus on the number or severity of symptoms necessary to make
the diagnosis.

There are also differences between individuals with developmental NVLD compared
to those with neurologically acquired NVLD disorders. It does appear, however,
that the incidence of NVLD has been on the rise over the past 10 to 15 years
(B. P. Rourke, personal communication, September, 1991). Advances in neonatology
have resulted in the survival of more significantly premature and potentially
neurologically compromised children than ever before. While prematurity itself
is not necessarily a risk factor for later cognitive problems (Siegel, 1983),
saving more premature infants does increase the pool of potentially at-risk
children.

Etiology

Rourke (1982) proposed the first comprehensive etiological model for NVLD based
on discrepancies between right and left hemisphere systems. Subsequently, he
revised and expanded his model to more effectively account for the range and
diversity of deficits observed in this disorder (Rourke, 1987, 1988). This revised
model proposed that deficits in subcortical white matter were responsible for
the symptoms seen in NVLD. Prior to this revision, deficits in right cerebral
hemisphere systems were thought to cause the NVLD syndrome. Currently, either
problem (directly related to right hemisphere systems or an inability to access
these right hemisphere systems due to deficits in white matter) is believed
to result in the syndrome.

A number of conditions affecting white matter areas of the brain have been
found to lead to the NVLD syndrome (Rourke, 1995). Some examples of neurological
disorders leading to white matter deficits and NVLD symptoms include callosal
agenesis (Smith & Rourke, 1995), hydrocephalus (Fletcher, Brookshire, Bohan,
Brandt, & Davidson, 1995), metachromatic leukodystrophy (Dool, Fuerst, & Rourke,
1995), multiple sclerosis (White & Krengel, 1995), encephalomyelitis, certain
types of traumatic brain injuries (Ewing-Cobbs, Fletcher, & Levin, 1995), and
toxic encephalopathies (White & Krengel, 1995). There is less direct evidence
to implicate defects in white matter as causal in developmental cases of the
disorder.

Recommendations for Treatment and Intervention

There is no mode of treatment available to reduce symptoms of NVLD. Some of
the early developmental deficits improve to some degree over time. However,
the primary neuropsychological deficits in tactile and visual perception and
motor coordination do not resolve completely. The most effective plans for intervention
focus on helping individuals compensate for their deficits. In order to do so
most effectively, proper diagnosis is necessary. This almost always necessitates
a comprehensive neuropsychological evaluation to delineate particular strengths
and weaknesses.

The following are some standard cautions used by the author to aid families
of NVLD children in monitoring potential areas of future difficulty. A behavioral
social skills intervention may be necessary to address inadequate social perception
and poor social problem-solving skills. Practical day-to-day activities sometimes
require more effort for children and adults with NVLD. These actvities include
difficulties with mechanical or fine motor operations (e.g., repairing things,
using simple tools, building models or puzzles), or difficulties with common
tasks requiring math and nonverbal skills, such as cooking. Compensatory techniques
can sometimes be helpful, such as relying on a compass, asking for a list of
specific landmarks along travel routes, carefully following recipes and instruction
manuals, and making procedural notes during tasks to document the steps already
completed.

Reading graphs, maps, and charts is often difficult because of the spatial
requirements of these tasks. Therefore, asking for written comments to explain
graphs, getting verbal directions, or reading figure captions and legends carefully
can prove helpful. Similarly, music instruction may be effortful. Reading notes,
recognizing tunes, keeping rhythm, and following patterns are tasks that are
often quite demanding for people with NVLD. When these problems with music are
present, it is important to de-emphasize participation in these types of tasks.
It may also be difficult for these individuals to listen to oral presentations
and take notes. If this occurs, compensatory techniques such as using a tape
recorder during lectures should be considered. Timed tests may not accurately
reflect actual knowledge or ability because problems with rapid processing of
visual-spatial information and problems with higher level reasoning often make
it difficult for individuals with NVLD to perform well when time is a factor.
Allowing additional time or completely removing time constraints reduce this
problem. Explicit directions, orally administered, may be difficult to follow
if the child is unclear how to proceed perceptually. In this sense, the comment,
"I see what you mean" may be appropriate; if a child with a nonverbal learning
disability cannot mentally "picture" what they have been asked to do, they may
fail on the task despite their capability of success. Having a teacher or "peer
tutor" check periodically to determine that the individual is proceeding correctly
can help.

Many practical difficulties can be observed in the classroom. Copying math
problems or other assignments from a book or chalkboard, writing lengthy reports,
or drawing maps could require too much effort. In general, activities requiring
drawing, copying, and writing are often difficult for children and adults with
NVLD. It may be necessary to have others assist with these tasks, perhaps by
providing teacher outlines or having other students offer copies of their own
papers.

The ability to solve computational math problems is frequently poor because
of misalignment of columns of numbers, poor recall of math facts, or a lack
of conceptual understanding. Each type of difficulty may require a different
type of intervention, such as using paper with columns, encouraging use of a
calculator, or providing examples of proper procedures for solving the problem.
Conceptually, math topics related to fractions, decimals, percents, geometry,
and trigonometry are typically particularly difficult. In addition, "survival
math" concepts involving time, money, and measurement concepts are sometimes
poor. Additional tutoring and instruction may be required and physical models
and manipulative aids may prove necessary to teach the basic concepts. Some
individuals with NVLD have difficulty with creative writing, book reports, essays,
and term papers. Because of their stronger verbal abilities, these individuals
often write lengthier passages using good vocabulary and well-constructed sentences.
Unfortunately, the result is often rambling and "empty," failing to convey anything
of substance and sometimes never "getting to the point." Teaching them to create
and follow outlines and providing editorial assistance with rough drafts may
prove helpful. They often need additional time to complete and revise these
writing assignments.

In addition to these cautionary examples, it is important to consider the appropriateness
of special education. There are no formal criteria defining special education
eligibility for children with NVLD. The direction of the discrepancy between
Verbal and Performance IQ scores, whereby Performance IQ exceeds Verbal IQ,
presents a particular difficulty. When a child demonstrates significantly better
performance than verbal abilities, nonverbal measures of intelligence are frequently
administered as alternative measures of "potential" (e.g., The Test of Nonverbal
Intelligence; Brown, Sherbenou, & Johnsen, 1990). Furthermore, children with
visual impairments or upper extremity hemiparesis are routinely evaluated using
only the verbal subtests from measures of intelligence to establish their "potential."
These "alternate" means for assessing general intelligence are commonly accepted
by nearly all school districts. However, many school districts do not recognize
the Verbal IQ score in isolation as a means for calculating discrepancy-based
eligibility for special education in NVLD children. This persists despite the
fact that these children are frequently incapable on visual-spatial measures
as visually impaired children are. Also, there are no commercially available
verbal intellectual measures for nonverbally disabled children that are analogous
to the Test of Nonverbal Intelligence.

Depending on their particular presentation, NVLD children may be classified
as learning-disabled (particularly in the area of math), as emotionally disturbed
due to their social and emotional problems, or as eligible for occupational
therapy because of their motor needs. Simply classifying NVLD children as learning
disabled overlooks the extent of their true needs. Similarly, classifying them
as eligible for special education on the basis of emotional or social deficits
is insufficient to address the global problems presented by this disorder. A
holistic approach to intervention must address academic deficiencies, motor
and sensory needs, social competency, and emotional well being.

Clinical Case History: Developmental NVLD in a Psychiatric Case

Background Information

C. K. is a 15-year-old boy attending the 9th grade. He was referred for neuropsychological
evaluation by his psychiatrist during an inpatient psychiatric hospitalization.
He has a long history of depression with suicidal ideation, persistent anxiety,
and aggressive behavior. He has been physically self-abusive and has also directed
his aggression toward peers and family members. At the time he was evaluated,
he was beginning his third psychiatric hospitalization. Decreased self-control,
school refusal, and suicidal ideation precipitated the current hospitalization.
Both prior hospitalizations were due to depression, self-abusive behavior, and
aggression toward family members. C. K. had no significant prior medical history.
He had been treated with a number of medications over the years, including Ritalin
and several antidepressants, but with little benefit.
C. K. had consistently performed poorly academically and had been placed in
a self- contained classroom for children with behavior disorders for the past
several years. He had no friends at school or at home and was frequently picked
on by other children. Because of his desire to be accepted socially, he frequently
attempted to imitate the actions of other delinquent adolescents, particularly
gang members. C. K. had been assaulted by other adolescents on several occasions
after flashing gang signs. When interviewed by the school counselors, it became
apparent that he had no idea what the gestures meant. He stated that he was
simply copying some of his other classmates. Most of his special education teachers
described him as a polite and caring adolescent. He was typically received favorably
by adults outside his immediate family.

Evaluation Results

On the WISC-III, C. K. obtained a Full Scale IQ score of 65 with a Verbal IQ
score of 78 and a Performance IQ score of 58. He also had a 22-point discrepancy
between his Verbal Comprehension Index and Perceptual Organization Index.
As shown in his summary of scores, only the most verbally
loaded of the Performance subtests (i.e., Picture Arrangement) scored near the
average range. Arithmetic was much poorer than either word recognition or spelling
on the Wide Range Achievement Test. Also, as frequently seen in children with
NVLD, his forward digit span was average while his backward digit span was very
poor.

Higher level reasoning was characterized by significant perseveration on the
Wisconsin Card Sorting Test. Perseveration occurs when an individual repeatedly
uses an incorrect problem solving strategy despite feedback that the strategy
is wrong. It also frequently signifies an inability to consider or derive alternative
solutions or strategies. Sequencing and ability to switch mental sets were also
extremely poor on the Trail Making Test, Part A and Part B. Verbal learning
and memory was poor on the Selective Reminding Test with erratic performance
across learning trials and poor delayed recall for the material. Unexpectedly,
C. K. also demonstrated moderate impairment for recall of meaningful paragraph
length stories on the Story Memory subtest of the Wide Range Assessment of Memory
and Learning. Many children with NVLD perform better on such semantic memory
tasks. As expected, nonverbal memory functions were very poor and deteriorated
in direct relation to the level of difficulty involved as seen by his poorer
performance on the Design Memory subtest (Example 1, Example 2) compared to
the Picture Memory subtest of the WRAML.

Receptive vocabulary was low average on the Peabody Picture Vocabulary Test
- Revised, consistent with his performance on the Vocabulary subtest of the
WISC-III. His poor confrontation naming abilities on the Boston Naming Test
and poor expressive fluency on the Controlled Oral Word Association Test reflected
the commonly seen deficits in more sophisticated aspects of expressive language
that are characteristic of NVLD. The Controlled Oral Word Association Test (Benton
& Hamsher, 1989) is a measure that allows the subject 60 seconds to generate
a list of words, excluding proper nouns, beginning with a particular letter
of the alphabet.

C. K. also demonstrated the hallmark of NVLD, impaired visual-spatial perception.
Some examples of his poor copying of designs on the Developmental Test of Visual-Motor
Integration are included (Example 1, Example 2, Example 3). His ability to copy
block designs was also extremely poor. All aspects of sensory-perceptual and
fine motor abilities scored within the impaired range. However, there was no
evidence of poorer left hand versus right hand performance. Fingertip number
writing, a task more dependent on right hemisphere processing, was much poorer
than finger localization, a task often related to functioning of the angular
gyrus in the left hemisphere.

Conclusion

As with many NVLD cases, C. K. did not present a completely classic pattern.
The discrepancy between Verbal and Performance IQ scores and the magnitude of
the discrepancy between Arithmetic and Reading and Arithmetic and Spelling on
the Wide Range Achievement Test - 3 were notable. In fact, these findings were
often the first indications to the examiner that a child might have NVLD, particularly
in school district evaluations. The fact that reading and spelling were average
while math was impaired also lent credence to the diagnosis of NVLD.
One diagnostic complication was the presence of more language problems than
would ideally be seen in this disorder. The fact that most of C. K.'s verbal
subtests were at least low average, his Verbal Comprehension Index was technically
within the Low Average range, reading and spelling were adequate, and receptive
vocabulary was low average, suggest that there is probably not an additional
primary language disorder present. However, some NVLD children do demonstrate
other cognitive deficits, including severe language disorders. This does not
necessarily preclude the diagnosis. However, it must be carefully demonstrated
that the pattern is not simply one of global cognitive dysfunction.
Most neuropsychologists agree that at least three signs of NVLD must be present
to make the diagnosis likely. These include a VIQ greater than PIQ discrepancy,
math poorer than reading and spelling, and evidence of significantly poor social
interaction. C. K. had each of these signs, as well as many additional features
of the disorder. There was substantial reason to believe that many of his psychiatric
problems were a direct result of an undiagnosed NVLD. In addition to a lifetime
of difficulty with learning and socialization, he was dismissed by teachers
and his parents as unwilling to work on his behavior problems. In fact, after
his parents and doctors were informed of the NVLD diagnosis, they were much
more supportive of C. K. and more tolerant of his behavior and learning problems.

Final Remarks

NVLD is a complex syndrome. Much work remains to be done to better delineate
its etiology, prevalence, and practical consequences. However, the work done
to date clearly indicates that this can be a disabling condition with many adverse
consequences for practical aspects of daily life. From an educational perspective,
revision of the concept of the handicapping condition within special education
may prove necessary. As neuropsychology has grown as a discipline of study,
we have become more aware of the complexity of human learning and its associated
problems. Despite this, our current definitions under special education law
frequently place inadequate emphasis on discrete cognitive processes, focusing
primarily on academic-achievement discrepancies. In order for children with
complex syndromes such as NVLD to be better and more appropriately served, it
is essential that educators, clinicians, and administrators become better informed
about the contributions of neuropsychology to understanding learning.

Author

Michael A. Roman received his Ph.D. in Clinical Psychology from IIT
in Chicago and completed a postdoctoral fellowship in Neuropsychology with an
emphasis on Child Neuropsychology in the Department of Neurology, Section of
Neuropsychology at the Medical College of Wisconsin in Milwaukee. He is currently
a Clinical Assistant Professor of Pediatrics at the University of Texas Health
Science Center in San Antonio and works in independent practice as a clinical
psychologist and neuropsychologist. He can be reached by e-mail at roman@uthscsa.dcci.com.

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