Learning disabilities are not a singular disorder but a group of varied and often multidimensional disorders.¹ Difficulties in learning may manifest themselves in various combinations of impairments in language, memory, visual-spatial organization, motor function, and the control of attention and impulses.²^,³ The characteristics of a child with a learning disability are often diverse and complex. Each child presents a different composite of system problems/impairments, functional deficits, preventing participation in activities and societal limitations.

The most commonly recognized performance difficulties in learning are associated with academic success. Fletcher and colleagues ⁴ argued that learning disabilities should be characterized as “unexpected” because the child is not learning up to expectations despite adequate instruction. Typically the areas of deficits are observed in verbal learning, including difficulties with reading, the acquisition of spoken and written language, and arithmetic. Impairments in nonverbal learning are equally important and more recently recognized. The three primary areas affected by nonverbal learning disorders include visual-spatial organization, social-emotional development, and sensorimotor performance.⁵ Accompanying behavioral manifestations may include problems with self-regulatory behaviors, such as lack of attention, hyperactivity, and poor impulse control. Difficulties in social perception and social interactions may also be observed.⁵^,⁶ These learning and behavioral difficulties may be isolated (e.g., academic, motor, or behavioral), combined (e.g., academic and motor), or global (academic, motor, and behavioral).⁷ In addition to verbal and nonverbal disabilities, specific motor impairments also can be present and affect academic achievement or daily life tasks.⁸^,⁹

Definition

The heterogeneity of persons with learning disabilities has made consensus on a single definition difficult. Many disciplines describe learning disabilities according to their own frames of reference. Medical professionals tend to relate the deficit to its cause, particularly to cerebral dysfunction. Terms historically used include brain injured,¹⁰ minimal brain dysfunction,² and psychoneurological disorder,¹¹ all implying a neurological cause for the deviation in development. Educational professionals, however, prefer to describe the child’s difficulties in behavioral or functional terms. Educators view children with learning disabilities as “children who fail to learn despite an apparently normal capacity for learning.”¹² Current terminology within the academic environment includes reading disorder, mathematics disorder, disorder of written expression, and intellectual disabilities (formerly called mental retardation).¹³^,¹⁴ The lack of consensus for one accepted definition continues to affect consistency in diagnosis, research, and intervention for persons with learning disabilities.

After multiple revisions, the National Joint Committee on Learning Disabilities (NJCLD), which represents several professional organizations, proposed the following definition:

Learning disability is a general term [for a condition] that:

Is intrinsic to the individual . . . [the term] refers to a heterogeneous group. (Each individual with learning disabilities presents with a unique profile of strengths and weakness.)

Results in significant difficulties in the acquisition and use of listening, speaking, reading, writing, reasoning, or mathematical abilities. (These difficulties are evident when appropriate levels of effort by the student do not result in expected performance, even when provided with effective instruction.)

Is presumed to be due to central nervous system dysfunction and may occur across the life span. (They persist throughout life and may change in their presentation and severity at different stages of life.)

May occur concomitantly with other impairments or other diagnoses. (For example, difficulties in self regulation and social interaction may exist separately or result from the learning disability. Individuals with attention-deficit disorders, emotional disturbances or intellectual disabilities may experience learning difficulties but these diagnoses do not cause or constitute them.)

Is not due to extrinsic factors. (Such as insufficient or inappropriate instruction, or cultural differences.)¹⁵

This definition identifies a proposed cause but does not provide a clear exclusion statement regarding what learning disabilities may not result from. A positive component of this definition is the lifelong nature of the condition. Also, by including the behavioral manifestations of regulatory and social difficulties, a more complete picture of functional problems for the individual with learning disabilities is presented. This could assist in the creation of more comprehensive and life-spanning programs of service and ultimately help in the recognition and remediation of functional and societal limitations.

The definition used in educational settings was initially passed in Public Law 94-142 and later incorporated into the Individuals with Disabilities Education Act (IDEA) (Section 602.26).

Children with learning disabilities are defined by IDEA as follows:

Individuals with a disorder in one or more of the basic psychological processes involved in understanding or using spoken or written language. (This emphasizes the receptive and expressive difficulties a student may demonstrate.)

Those who are experiencing difficulties in the ability to listen, think, speak, read, write, spell, or do mathematical calculations. (These highlight the academic difficulties the student may experience.)

Those who may have conditions such as perceptual disabilities, brain injury, minimal brain dysfunction, dyslexia, and developmental aphasia.

Those who have a learning problem that does not result from other disabilities such as motor deficits, emotional disturbances, or environmental, cultural, or economic differences.

This description does not specifically address cause but does highlight psychological processes versus neurological impairments. The primary disability focus is on language, which may exclude difficulties in learning that involve nonverbal reasoning. This definition does not mention regulatory, reasoning, and social perception difficulties that may contribute to understanding the student’s complete profile. On a foundational level this definition formed the basis for creating academic programs and delineating appropriate services for children with learning disabilities.

IDEA mandates that all children will have free and appropriate education and authorizes aid for special education and educationally relevant services for children with disabilities. IDEA influences how children with learning disabilities are identified and classified. The 1997 amendments of IDEA, by promoting the early identification and provision of services, redirected the focus of special education services by adding provisions that would enable children with disabilities to make greater progress and achieve higher levels of functional performance.¹⁶

The IDEA 2004 amendments eliminate a previous requirement that students must exhibit a severe discrepancy between intellectual ability and achievement for eligibility. This “severe discrepancy” policy often mandated that children would have to experience failure for several years to demonstrate the requisite degree of discrepancy.¹⁷ The current goal is to identify ways of serving students more quickly and efficiently once they begin to show signs of difficulty.¹⁷ Congress also indicated specifically that (1) IQ tests could not be required for the identification of students for special education in the learning disabilities category, and (2) states had to allow districts to implement identification models that used Response to Instruction (RTI).¹⁸ The RTI models suggest that the learning difficulty may be intrinsic to the child, inherent in the instruction, or a combination of both. The models propose systematically altering the quality of instruction and repeatedly measuring the child’s response to that instruction. Inferences can then be made about the child’s deficits contributing to learning difficulties.¹⁹

IDEA 2004 also limits the schools from finding a student eligible for special education services if the learning problems are determined to be caused by a lack of appropriate instruction. The law now encourages schools to use scientific, research-based interventions to maximize a student’s opportunity for success in the general education setting (least restrictive environment [LRE]) before being placed in special education. IDEA encourages educators to stress the importance of identifying individual differences and patterns of ability within each child and adjust the educational methods accordingly. Academic achievement relies heavily on the effectiveness of the teacher and the instructional techniques. Studies indicate that learning disabilities do not fall evenly across racial and ethnic groups, with a higher incidence of special education services needed for black, non-Hispanic children.²⁰ The No Child Left Behind Act challenges states and school districts to become more accountable for improving educational standards by intensifying their efforts to close the achievement gap between underachieving students and their peers.

Classifications

The two most widely used classification systems are those of the American Psychiatric Association (Diagnostic and Statistical Manual of Mental Disorders [DSM])²¹ and the World Health Organization (WHO) (International Classification of Diseases [ICD]).²² Educational professionals prefer the DSM classification for its academic relevance. A variety of specific academically related disorders are outlined in the DSM. The latest edition, DSM-IV-TR, classifies learning disabilities under “disorders usually first diagnosed in infancy, childhood, or adolescence.” It subclassifies disorders into the following categories:

Learning Disorders

Reading disorder

Mathematics disorder

Disorder of written expression

Motor Skills

Developmental coordination disorder

Communication Disorders

Expressive language disorder

Mixed receptive-expressive disorder

Phonological disorder

Stuttering

The classification system commonly used by therapists is the ICD. The ICD codes are state mandated diagnostic codes used for billing and information purposes. In the recently revised ICD-10 the category “specific delays in development,” which included “other specific learning difficulties,” was changed to “disorders of psychological development.” The term “learning” is no longer part of this classification. This updated classification is as follows:

Disorders of Psychological Development

Including specific developmental disorders (SDD) of speech and language (including acquired aphasia with epilepsy)

SDD of scholastic skills

SDD of motor function

Pervasive developmental disorder

Model of disablement

Beyond classifying learning disabilities as a diagnosis, the National Center for Medical Rehabilitation Research (NCMRR)²³ and WHO have integrated related approaches to classify functional performance. This conceptual approach, the Model of Disablement, describes the multiple dimensions of disability and identifies various internal and external factors that affect the way a disability manifests. The purpose of this model is to shift classification of a disability to include assessment of functional performance and societal participation as opposed to solely identifying component deficit areas.

Five dimensions are outlined in the Model of Disablement. They include pathophysiology, impairments, functional limitations, disabilities, and societal limitations. Pathophysiology refers to the underlying disease or injury processes at the tissue or cellular level. Proposed causative factors related to learning disabilities at this level include brain damage, biochemical abnormalities, genetics, and metabolic disorders. The challenge for interventionists is to recognize the signs and symptoms that confirm the diagnosis.²⁴

The second dimension, impairment, includes the organ and system dysfunction that potentially has a negative effect on functional performance. Children with learning disabilities may demonstrate impaired balance, endurance, and coordination of movements. Impairments that occur in one or more systems may lead to functional limitations, the third dimension. The challenge for the clinician is to treat impairments within the context of daily functional performance because impairments do not always result in functional limitation.

Functional limitations involve whole-body functions that are typically assessed but may or may not receive remediation.²⁴ For a child with learning disabilities this may include poor hand function in the performance of manipulation activities involved in dressing and handwriting. When persistent functional limitations are not remediable and cannot be adequately compensated for with assistive technology or other supports, disabilities in daily life occur. The child then fails to be an active participant in life roles, such as activities of daily living and school tasks. Emotional difficulties, such as depression and decreased self-esteem, which may result from learning difficulties, can ultimately impair social interactions.

Community and environmental barriers, called societal limitations, also can lead to restriction in social participation. An example of structural or attitudinal barriers that prevent optimal participation in society is a child who cannot use playground equipment because of lack of accessibility. The ultimate goal for the clinician is to facilitate functional abilities and performance as well as provide necessary supports so the child can become an active participant in society.

The Model of Disablement proposes that the environment, purpose, and level of participation should all be considered when evaluating performance. Determination of the presence, severity, or kind of disability should be made on the basis of a combination of these factors. Within this framework, a clinician does not assume that a handicap exists because of an impairment but rather considers levels of functional and societal abilities. This allows the therapist to determine intervention needs based on functional performance in relevant environments rather than being driven purely by diagnosis. A 9-year-old child with learning disabilities, for example, might have impairments in motor components of muscle strength and balance. Although these impairments can be identified on assessment, the Model of Disablement suggests that a disability does not exist unless these deficits affect functional performance (e.g., ascending and descending stairs) and limit societal participation (e.g., child cannot leave house independently to go to school or play). The identified impairments, based on assessment in an academic setting, would have to affect participation within the educational environment (be educationally relevant) to warrant intervention.

Incidence and prevalence

Current data indicate that 15 million children nationwide have been diagnosed with some kind of learning disability.²⁵ According to a 2007 report to Congress on the implementation of IDEA, nearly 2.6 million students aged 6 to 21 years are receiving special education services for specific learning disabilities. As of 2007, this represents 44% of students with disabilities nationwide.²⁵ Children with specific learning disabilities represent the highest incidence (number of new cases identified in a given period) among 13 disability categories, representing 44% of the total population of children receiving special education. Overall, the estimated prevalence (total number of cases in a population at a given time) of learning disabilities is approximately 15% of the U.S. population, which translates to one out of seven people.⁹ In children under age 18 years, 8% to 10% of the population have some type of learning disability.²⁶ Boys are more likely than girls to be identified as having a learning disability. According to Child Trends, 10% of boys and 6% of girls aged 3 to 17 years had a learning disability in 2004.²⁷

Perspectives on the causes of learning disabilities

Learning disability is a diverse diagnosis with varied manifestations; therefore searching for a single cause would be inadequate. Historically, researchers have studied causative factors including (1) brain damage or dysfunction caused by birth injury, perinatal anoxia, head injury, fetal malnutrition, encephalitis, and lead poisoning; (2) allergies; (3) biochemical abnormalities or metabolic disorders; (4) genetics; (5) maturational lag; and (6) environmental factors, such as neglect and abuse, a disorganized home, and inadequate stimulation.28–30

Current sources agree that possible causes of learning disabilities can include problems with pregnancy and birth (e.g., drug and alcohol use, low birth weight, anoxia, and premature or prolonged labor), and incidents occurring after birth (e.g., head injuries, nutritional deprivation, and exposure to toxic substances such as lead).31–34 Genetic and hereditary links also have been observed, with learning difficulties often seen across generations within families.³⁴ The emotional and social environment have also been considered as a contributing factor to learning disabilities.¹⁴

Children with learning disabilities frequently display a composite of neuropsychological symptoms that interfere with the ability to store, process, or produce information. These symptoms typically include disorders of speech, spatial orientation, perception, motor coordination, and activity level. Researchers have attempted to identify areas of the brain that may be responsible for these functional limitations. Tools being used include empirical measures of physiological function such as electroencephalography, event-related potentials (ERPs), brain electrical activity mapping (BEAM), regional cerebral blood flow (rCBF), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI). These measures expand the understanding of brain functioning but are best used in conjunction with data on functional and behavioral manifestations.

Research findings on brain structure have documented that certain functions are specialized within each hemisphere and this specialization is optimal for efficient learning.³⁵^,³⁶ The left hemisphere processes information in a sequential, linear fashion and is more proficient at analyzing details. Academically, this hemisphere is responsible for recognizing words and comprehending material read, performing mathematical calculations, and processing and producing language.

The right hemisphere processes input in a more holistic manner, grasping the overall organization or the “gestalt” of a pattern.³⁷^,³⁸ This type of organization is advantageous for spatial processing and visual perception. Functionally, the right hemisphere synthesizes nonverbal stimuli, such as environmental sounds and voice intonation, recognizes and interprets facial expressions, and contributes to mathematical reasoning and judgment. Over time these differences in left and right brain processing have become accepted and are commonly labels of cognitive style (i.e., left-brained versus right-brained learner).

A strict left-right dichotomy is oversimplified because it does not take into account many aspects of functional brain organization.³⁷^,³⁹ Both hemispheres must work together for a variety of specific academic outcomes such as reading and mathematical concepts. In addition to the communication that occurs between the hemispheres via the corpus callosum, essential communication within the hemispheres is also present. Intrahemispheric communication is critical for developing higher level cognitive functions such as memory, language, visual-spatial perception, and praxis.⁴⁰ Research suggests that children with learning disabilities show different patterns of cerebral organization than normal children.³⁷^,³⁹ However, brain plasticity is the basis for designing and implementing a variety of intervention techniques aimed at improving processing.

Subgroups

In early attempts to classify learning disabilities, Denckla and Rudel ⁴¹ determined that approximately 30% of the 190 children they assessed by neurological examination could be classified into three recognizable subgroups. The other 70% exhibited an unclassifiable mixture of signs. Of the 30%, the first subgroup was classified as children having a specific language disability. These children, who were failing reading and spelling, showed a pattern of inadequacy in repetition, sequencing, memory, language, motor, and other tasks, all of which require rote functioning. The second group had a specific visual-spatial disability. These children had average performance in reading and spelling with delayed arithmetic, writing, and copying skills. The children in this subgroup all had social and/or emotional difficulties. The third group manifested a dyscontrol syndrome. These children had decreased motor and impulse control, were behaviorally immature, and were average in language and perceptual functioning.

Grouping children with learning disabilities based on patterns of academic strengths and weakness is as important as grouping them based on neuropsychological or cognitive measures. With an academic classification the heterogeneity of learning disabilities can be more clearly recognized and learning modalities can be adjusted to the individual child. A child with a specific reading difficulty, for example, could be experiencing deficits in word recognition, fluency, or comprehension. Through identification of the specific areas of weakness in reading, intervention can be individualized to improve academic performance.⁴

Based on historical and current trends the following general subgroups will be explored: verbal learning impairments, nonverbal learning disabilities (NVLDs), motor coordination deficits, and social and emotional challenges.

Verbal learning impairments

Verbal learning impairments typically include dyslexia, dyscalculia, and dysgraphia. Harris ¹³ classifies these deficits in functional terms, with dyslexia including disorders of reading and spelling, dyscalculia denoting a mathematics disorder, and dysgraphia describing a disorder of written expression. These learning disorders may occur individually or concurrently. Each of these verbal learning impairments will significantly influence academic performance.

Dyslexia (developmental reading disorder).

Dyslexia is a learning impairment in which the ability to read with accuracy and comprehension is substantially less than expected for age, intelligence, and education and that impairs academic achievement or daily living.²¹ The International Dyslexia Association adopted the following definition in 2002: “Dyslexia is a specific learning disability that is neurological in origin. It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction. Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede the growth of vocabulary and background knowledge.”⁴²

Characteristics of dyslexia include the following ⁴³^,⁴⁴:

Difficulty learning to recognize written words

An inability to sound out the pronunciation of an unfamiliar word

Seeing letters or words in reverse (b for d or saw for was)—although seeing words or letters in reverse is common for children younger than 8 who do not have dyslexia, children with dyslexia will continue to see reversals past that age

Difficulty comprehending rapid instructions or following more than one command at a time

Problems remembering the sequence of things, such as learning the order of the alphabet or spelling

Difficulty distinguishing between similar sounds in words; mixing up sounds in multisyllable words (auditory discrimination) (e.g., aminal for animal, bisghetti for spaghetti)

Slow or inaccurate reading, with difficulty reading out loud

Difficulty rhyming

Dyslexia is the most common learning disorder, affecting as many as 80% of individuals identified as learning disabled.⁴⁵ Prevalence rates range from 10% to 15% of the school-aged population,⁴⁶ with the highest noted estimate of 17.4%.⁴⁷ Historically, dyslexia was considered more common in boys than in girls, but data indicate an equal distribution between the sexes.⁴⁸ Boys are more likely to act out as a result of having a reading difficulty and are therefore more likely to be identified early. Girls, on the other hand, are more likely to try to “hide” their difficulty, becoming quiet and reserved.¹⁸

Causes of dyslexia can be both genetic and neurobiological.¹⁴^,¹⁸^,⁴² Genetic causation has been linked to chromosomes 1, 2, 3, 6, 11, 13, 15, and 18.⁴⁹ There is a strong inheritability of the genetic links for dyslexia. Statistics suggest that 30% to 50% of children with dyslexia have a parent with the disorder.⁵⁰ Neuroanatomical abnormalities, atypical brain symmetry, and disruptions in neural processing have been observed in children with reading disorders.¹⁴^,¹⁸^,⁴⁸^,⁵¹ Anatomically, the measurements that best discriminate between children with and without dyslexia are the right anterior lobe of the cerebellum and the area involving the inferior frontal gyrus of both hemispheres.¹⁸ Dynamic investigations using functional brain imagining techniques (PET, fMRI, and the newer ultrafast echo planar imaging [EPI]) are providing significant information on brain functioning during cognitive tasks such as reading and picture naming.¹⁴^,⁴⁸

Reading skills consist of a combination of visually perceiving whole words and phonetically decoding letters, morphemes, and words.⁵² Individuals with reading disorders exhibit brain activation patterns that provide evidence of an imperfectly functioning system for segmenting words into phonological (language) parts and linking the visual representations of letters to the sounds they represent.⁴⁷ These disruptions of the posterior reading system result in increased reliance on ancillary systems during reading tasks, including the frontal lobe and right hemisphere posterior circuitry. This suggests that the child with dyslexia may be compensating for poor phonological skills with other perceptual processes, helping to explain why individuals with dyslexia can develop reading skills, although they often remain slow and nonautomatic.⁴⁸

Dyscalculia (mathematics disorder).

Dyscalculia is a learning impairment in which mathematical ability is substantially less than expected for age, intelligence, and education and that impairs academic achievement or daily living.²¹ Difficulties occur with comprehending a variety of math concepts, including number quantities, money, time, and measurement. This disorder also involves difficulties with computations and problem solving of specific math functions, which affects the ability to understand, remember, or manipulate numbers or number facts.¹⁸ This heterogeneous disorder may involve both intrinsic and extrinsic factors.⁵³ Intrinsic factors are hypothesized to include deficits in visual-spatial skill, quantitative reasoning, sequencing, memory, or intelligence. Extrinsic factors can be a combination of poor instruction in the mastery of prerequisite skills as well as attitude, interest, and confidence in the subject.

Characteristics of dyscalculia include the following ⁵⁴:

Confusing numbers and math symbols (+, −, ×, ÷)

Inconsistent ability in addition, subtraction, multiplication, and division

Problems sequencing numbers, or transposing them when repeated

Difficulty with abstract concepts of time and direction

Poor mental math ability

Difficulty with money, budgeting, balancing checkbooks, and financial thinking (e.g., checking change or estimating the cost of items in a shopping basket)

Problem reading analog clocks

Trouble keeping score during games and playing games with flexible rules of scoring such as poker

Prevalence of dyscalculia is 5% to 6% in the school-aged population, with a nearly equal male-to-female ratio.¹⁴^,⁵⁵ Geary⁵⁶ concludes that individuals with arithmetic disabilities currently appear to constitute at least two subgroups: those with only mathematic disorders and those with concomitant reading disorders and/or attention-deficit disorder.

Although there is evidence that this disorder is familial and heritable, much less research on its cause is provided than on the causes of most other learning disorders. Dyscalculia shares genetic influences with reading and language measures. The association between dyslexia and dyscalculia seems to be largely genetically mediated.¹⁴^,⁵⁵ Other risk factors for development of dyscalculia include prematurity and low birth weight. In addition, environmental deprivation, poor teaching, classroom diversity, and untested curricula have been linked to cause.⁵⁵

The neurological cause of dyscalculia was initially hypothesized to be right hemisphere dysfunction because of the strong relation of visual-spatial skills to numerical computation.⁵⁷ Additional research supports the involvement of both hemispheres because mathematics computation involves a complex relation of spatial problem solving, sequential analysis, language processing, and memory.⁵⁵ Specifically involved are portions of the parietal and frontal lobes.¹⁴ In an effort to compensate, individuals with dyscalculia can recruit alternate brain areas, but this substitution often results in inefficient cognitive functioning.⁵⁵

Dysgraphia (disorder of written expression).

Dysgraphia is a learning impairment in which writing ability is substantially less than expected for age, intelligence, and education that impairs academic achievement or daily living.²¹ The DSM, fourth edition (DSM-IV) diagnosis of “disorder of written expression” depends on recognition of “writing skills substantially below those expected given the person’s chronological age, measured intelligence, and age appropriate education” that “significantly interferes with academic achievement or activities of daily living that require composition of written texts.”²¹ Children with dysgraphia have specific difficulties in the ability to write, regardless of the ability to read. This may include problems using words appropriately, putting thoughts into words, or mastering the mechanics of writing. Classifications of dysgraphia can include penmanship-related aspects of writing (e.g., motor control and execution), linguistic aspects of writing (e.g., spelling and composing), or a combination.⁵⁸ This heterogeneous disorder is frequently found in combination with other academic, learning, and attention disorders.¹³^,¹⁸

Characteristics of dysgraphia include the following ⁵⁹:

Poor legibility: irregular letter size and shapes, poor spacing

Mixing uppercase and lowercase letters; unfinished letters

Spelling difficulties

Fatigues quickly or complains of pain when writing

Decreased or increased speed of copying or writing

Needs to say words out loud while writing

Struggles with organizing thoughts on paper

Difficulty writing grammatically correct sentences and organized paragraphs

Large gap between knowledge base and ability to express ideas in writing

Awkward pencil grip

Limited data are available on the prevalence of dysgraphia. Although 10% to 30% of school-aged children struggle with handwriting, we cannot assume they have been diagnosed with dysgraphia.⁶⁰ Difficulties in written expression are frequently underidentified and can be masked by reading disorders or considered to be attributable to poor motivation. Studies have suggested that dysgraphia may be as common as reading disorders and may occur in 3% to 4% of the population.¹³^,⁵⁸

Dysgraphia has been suggested to be a neurological processing disorder that seldom occurs in isolation and can result from a number of other dysfunctions, including attention deficit, auditory or visual processing weakness, and sequencing problems.¹⁴^,⁶¹ The complex nature of written expression makes finding the cause difficult. Writing involves integration of spatial and linguistic functions, planning, memory, and motor output. This suggests involvement of both the left and right hemispheres for skill in decoding, spelling, formulating and sequencing ideas, and producing work in correct spatial orientation, all coupled with rules of punctuation and capitalization.

Nonverbal learning disability

NVLDs (or NLDs) are considered by some to be a neuropsychological disability. Although this condition has been identified for more than 30 years, it has not yet been included as a diagnostic category in the DSM.⁶² The pioneer in the field, Dr. Byron P. Rourke, first identified in 1985 this separate and distinct learning disability. In 1995 he defined nonverbal disability as “a dysfunction of the brain’s right hemisphere—that part of the brain which processes nonverbal, performance-based information, including visual-spatial, intuitive, organizational and evaluative processing functions.”⁶³ Nonverbal learning disorders affect both academic performance and social interactions in children. Three primary areas affected by NVLDs include visual-spatial organization, sensory-motor integration, and social-emotional development. The social and emotional difficulties for individuals with nonverbal learning disorders are paramount, leading some researchers to label this a social-emotional learning disability.¹³^,⁶⁴ NVLDs are generally identified by a distinct pattern of strengths and deficits, with excellent verbal and rote memory skills and poorly developed sensory-motor and graphomotor ability, executive functioning, and social interactions.¹³^,⁶⁵^,⁶⁶

Characteristics of NVLDs include the following ¹⁴^,⁶²^,⁶⁷:

Higher verbal IQ compared with performance (nonverbal) on the Wechsler Intelligence Scale for Children (WISC)

Develops speech, language, and reading skills early

Strong vocabulary and spelling

Ability to memorize and repeat a massive amount of information provided it is in spoken form

Learns better and faster through hearing information rather than seeing it

Difficulties with constructional and spatial planning tasks

Fine and gross motor difficulties affecting printing and cursive writing, physical coordination, and balance

May exhibit limited facial expression, flat affect, unchanging voice intonation, and robotic speech

Poor interpretation of emotional responses made by others

Trouble reading and understanding facial expressions, gestures, and voice intonations

Nuances of spoken language, such as hidden meanings, figures of speech, jokes, and metaphors are interpreted on a concrete level

Struggles with conversation skills, dealing with new situations, and changing performance in response to interactional cues

Difficulties in problem solving and understanding cause-effect relationships

Poor awareness of social space

Can be intrusive and disruptive

NVLDs make up 5% to 10% of all individuals with learning disabilities.⁶⁸ NVLD is frequently overlooked in the educational arena because children with this disorder are highly verbal and develop an extensive vocabulary at a young age. Well-developed memory for rote verbal information positively influences early academic learning of reading and spelling. Yet these students will have difficulty performing in situations where adaptability and speed are necessary, and their written output will be slow and laborious.⁶⁵ Nonverbal learning disorders are therefore challenging to identify at younger ages but become progressively more apparent and debilitating by adolescence and adulthood. The challenges in early identification, the absence from the DSM-IV, and the different views held by psychological and educational disciplines often result in lack of awareness of, accurate diagnosis of, and appropriate service provision for these students.

Little is known about possible genetic or environmental causes of NVLD. There are no family, twin, adoption, segregation, or linkage studies available.¹⁴ Pennington¹⁴ proposes that both Turner syndrome and fragile X syndrome in females appear to be possible genetic causes of NVLD. Similarities include deficits in executive functions, increased difficulties in math versus reading and spelling, functional structural language but impaired pragmatic language, and social anxiety and shyness.¹⁴ Differential diagnosis is essential because NVLD can occur in conjunction with dyscalculia, attention deficit, adjustment disorder, anxiety and depression, emotional disturbances, and obsessive-compulsive tendencies.

Motor coordination deficits

Children with learning disabilities may or may not manifest motor coordination problems. Conversely, some children have motor and coordination problems but do not experience learning difficulties. Children with motor deficits typically have difficulty acquiring age-appropriate motor skills and move in an awkward and clumsy manner. Difficulties in daily functional tasks and performance areas (e.g., school and leisure skills) are common. Motor deficits can result from a wide variety of neurological, physiological, developmental, and environmental factors. These impairments can manifest in diverse ways depending on the severity of the disorder and the areas of motor and social performance affected. This will be discussed at length in the next section.

Social and emotional challenges

Behavioral patterns or disorders associated with learning disabilities include frustration, anxiety, depression, attention deficits, conduct problems, and global behavior problems. Ames ⁶⁹ stressed that no single behavior pattern is prevalent in children with learning disabilities. Children with learning disabilities not only struggle in the classroom, but experience difficulties in the social arena as well.⁷⁰ Issues in learning and related behaviors affect one another in a complex manner, leaving us to wonder which is the cause and which is the symptom.

Frustration, deflated self-esteem, and other social and emotional difficulties tend to emerge when instruction does not match learning styles.⁷¹ This frustration mounts as the child notices classmates surpassing them, and this often results in exasperation with trying to keep up. The pressure then becomes for the child to “try harder,” when ironically most do not understand just how hard the child is trying. The dissatisfaction in not meeting the teacher’s expectations is often overshadowed by the inability to succeed in personal goals and a lack of self-worth. This can result in the development of internal perfectionism to deal with the lack of competence, with the belief of the child that he or she should not make mistakes.⁷²

Anxiety is another response that may occur with persistent difficulties in understanding and successfully completing schoolwork. This occurs when the child feels out of control and lacks the ability to plan and execute strategies for success.⁷¹ The mismatch between ability, expectations, and outcomes can cause frustration, disappointment, and stress, triggering a range of emotions and behaviors that interfere with everyday functioning in multiple environments.⁷¹

Other emotional difficulties are noted in attention. When a lesson is taught in a manner that is too complex, the child may become inattentive. Attention problems can influence behavior, often relating to difficulties with impulse control, restlessness, and irritability, affecting learning and peer interactions. These issues frequently coincide with frustration, anger, and resentment, which may manifest as a conduct problem (e.g., verbal and nonverbal aggression, destructiveness, and significant difficulties interacting with peers). Children with learning disabilities often become discouraged and fearful, are less motivated, and develop negative and defensive attitudes. These patterns of behavior can worsen with age, contributing to juvenile deliquency.³ Low self-esteem and depression are common during school years and tend to escalate around age 10 years.⁷³

Poor academic progress, additional prompting needed from teachers, and negative attention for disruptive behaviors can cause children with learning disabilities to perceive themselves as being “different.”⁷⁴ Lack of success in school experiences can influence the development of positive self-perception and can have powerfully negative effects on self-esteem.⁷¹ A self-defeating cycle may be established: the child experiences learning problems, school and home environments become increasingly tense, and disruptive behaviors become more pronounced. These responses, in turn, further affect the child’s ability to learn. Lack of success generates more failure until the child anticipates defeat in almost every situation.

Assessment and intervention

Specialists

Evaluation and intervention for children with learning disabilities should involve an interdisciplinary team owing to the varied nature of presenting problems. Most children with learning disabilities are seen by a group of professionals, the makeup of which depends on the purpose, location, philosophical orientation, or availability of resources of a particular program. Box 14-1 lists the different professionals and specialists who might participate in assessment or remediation of children with learning disabilities. The types of professionals are grouped into the four categories of education, medicine and nursing, psychology, and special services; they have been listed only once, although some professions could be categorized in multiple ways.

BOX 14-1 TYPES OF SPECIALISTS WORKING WITH CHILDREN WITH LEARNING DISABILITIES

Learning disability specialist

Educational diagnostician

Reading specialist

Physical educator

Adaptive physical educator

Medicine and nursing

Family physician

Pediatrician

Pediatric neurologist

Ophthalmologist or optometrist

Otologist or ear, nose, and throat (ENT) specialist

Psychology

Clinical psychologist

Occupational therapist

Physical therapist

Speech and language pathologist

Audiologist

Vision specialist

Social worker

Recreational therapist

Music therapist

Vocational education specialist

Therapists should be familiar with the roles of the various medical specialists and of primary care physicians. Psychologists have two distinct and often separate roles in the care of children with learning disorders. The first role is in identification of learning strengths and weaknesses. Psychological testing is often essential in the recognition of specific learning problems and may be done by clinical psychologists, school psychologists, or clinical neuropsychologists who specialize in diagnosis of learning disorders. The second role of psychologists is to provide mental health services and support systems to address academic, social-emotional, and behavioral issues. Counseling and behavior management can also be provided by a psychiatrist, behavioral specialist, or social worker. School adjustment or guidance counselors offer support and advice on specific academic difficulties, social conflicts, and affective issues.

Physical educators, adaptive physical educators, physical therapists (PTs), occupational therapists (OTs), and speech therapists also may be involved in the assessment of motor deficits and related areas. Overlap in the areas assessed may occur. The unique training of each professional influences both the selection of tests and the qualitative aspects of assessment on the basis of observations of a child’s performance. Although the evaluations may appear similar, differences among professions are apparent in orientation and rationale when interpreting dysfunction.

Planning an assessment protocol can prevent unnecessary duplication of testing and provide comprehensive information related to the referral concerns. The assessment is driven by the referral concerns and the functional difficulties the child is experiencing. Communication of information between professionals and the parents will generate a comprehensive picture of the child’s areas of strength and weakness, necessary for effective intervention planning.

Coordinating multiple interventions

As the number of disciplines involved in the assessment and therapeutic management of children with learning disabilities has steadily increased, communication for effective programming has become more challenging. Despite the benefits of specific skills brought to the case by each professional, the huge variety of well-meaning recommendations can result in service delivery overkill. Case Study 14-1 provides an example of the negative impact of overabundant specialized intervention on the child and family. In this case, if all the interventionists had communicated, a more realistic and effective plan could have been developed.

CASE STUDY 14-1 MATT

Matt is an 8-year-old boy who was referred for clinic-based physical therapy intervention for 1 hour per week for remediation of severe motor coordination and planning problems that accompanied his learning disability. In addition to Matt’s weekly treatment sessions, suggestions were made to his mother for a home program to be accomplished three times a week for 15 to 30 minutes each time. Meanwhile, Matt also received other services. Although he was mainstreamed into a regular classroom in accordance with the special education law, he was seen by the resource teacher on a daily basis and by the adaptive physical education teacher twice a week to meet his specialized needs. The classroom teacher told Matt’s mother that Matt must read at least one book a night because he needed additional reading practice. A reading tutor came to Matt’s house on Saturday mornings. Ocular motor problems were identified, so he was evaluated by an optometrist, who recommended weekly visits plus ocular exercises for 30 minutes a day. Matt developed secondary emotional problems, partly because he was bright yet aware of his learning disability and frustrated by it. Thus Matt also saw a psychotherapist on a weekly basis. The psychotherapist recommended participation in weekly group sessions, in addition to Matt’s individual sessions, to help improve peer relationships. Thus Matt’s therapists had developed a 12-hour-a-day program for him and his family. It was no wonder that Matt had difficulty in developing peer relationships; he never had time. Matt’s schedule also affected interaction in his own family. His mother believed that being a “therapist” to Matt interfered with her role as his mother. She felt unable to carry out the home program and felt guilty for not doing it.

What became apparent with Matt’s case was that although each professional involved with him made an important contribution to evaluation and intervention, the massive input, to some extent, had a detrimental effect on Matt and his family. Coordinating interventions and providing additional support at home can create a drain on the family and limit time for family activities and extracurricular participation.

Effective coordination of intervention services presents a dilemma because no single discipline is specifically trained for that role.⁷⁵ Kenny and Burka⁷⁵ stress the need for a person to act as a coordinator for the management and integration of the interventions received by the child. Unfortunately, this role does not exist; therefore the parent must assume this responsibility.

School-based service delivery models

The model of service delivery for each individual child should be developed to facilitate the student’s ability to be successful in the learning environment. A continuum of services exists to enable interventionists to be responsive to all children’s needs. The continuum includes consultation, integrated or supervised therapy, and direct service.⁷⁶ Unfortunately, a lack of available resources can influence what type and frequency of services are provided. In creating a plan that truly addresses the issues hindering a child’s learning within the academic setting, the team must work together to fabricate relevant and inclusive goals.

IDEA currently requires that all children in special education be educated in the least restrictive environment. The law requires that students with disabilities be educated to the extent appropriate with their peers, within the inclusion classroom. Removing the child from the classroom for special education and intervention is discouraged unless it is absolutely necessary for the student to learn effectively. Although the model of inclusion can be effective for many children, it requires members of the team to work closely together with the regular education teacher. This collaborative effort ensures an understanding of the child’s special learning needs and incorporation of therapeutic procedures into the regular classroom to facilitate the best learning environment.

Bricker ⁷⁷ contends that adhering strictly to this model can be detrimental to certain students, and each case must be looked at individually. The least restrictive environment should be determined after assessing the specific needs of the child. If services in a regular classroom, coupled with supplemental aids and services, do not meet the needs of the child, an alternate environment should be considered. The first adaptation might be to have the child participate for the majority of the day in the regular classroom and leave for special instruction for part of the day. In some educational settings, children with learning disabilities are given full-time instruction in a special classroom with a small group of other children with learning disabilities. A special education teacher or a learning disability specialist is in charge of the classroom. The most specialized environment would be a private school only for children with learning disabilities.

Learning disabilities and motor deficits or developmental coordination disorder

Approximately half of children with learning disabilities have motor coordination problems.⁷⁸ Motor deficits are often the most overt sign of difficulty for the child with learning disabilities. Lowered academic achievement within any or all areas of learning (reading, spelling, writing) is also seen in children with developmental coordination disorder (DCD).⁸^,²¹ A study by Jongmans and colleagues⁷⁸ indicates that children with concomitant perceptual-motor and learning problems are more severely affected in motor difficulties than those with only DCD or who are only learning disabled. At times, extreme discrepancy in competence over a range of motor skills exists, with strengths in some motor areas and significant weaknesses in others. Presentation of difficulties may change over time depending on developmental maturation, environmental demands, and interventions received.

An International Consensus Meeting on Children and Clumsiness was held in 1994 with expert educators, kinesiologists, OTs, PTs, psychologists, and parents. These experts discussed a common name to identify “clumsy” children with movement, coordination, and motor planning difficulties. The term developmental coordination disorder (DCD), as first described in DSM-III,²¹ was identified to distinguish these children from those with severe motor impairments (such as those with cerebral palsy or paraplegia) and children with normal motor movements. A child with DCD often exhibits difficulty with motoric academic tasks such as handwriting and gym class, self-care skills such as dressing and using utensils, and leisure activities including playground games and social interactions.⁷⁹