Doris J. Johnson, Ph.D.
Children with learning disabilities are a heterogeneous population who have no primary sensory deficits, mental retardation, emotional disturbance, or motor handicaps; however, they have problems processing information that interfere with one or more areas of achievement, including listening comprehension, speaking (oral expressive language), reading, written language, mathematics, reasoning, or various aspects of nonverbal learning (e.g., spatial orientation). As a group, they have many integrities, but they are not learning at the level expected for their overall mental ability. The symptoms and age of identification vary with the type and severity of the disability.
Various theoretical perspectives are used in research, assessment, and intervention. Because many of the early observations of children with learning disabilities were made by neurologists, theories related to brain-behavior relationships and neuropsychology have provided an understanding of patterns of problems that co-occur, as well as the biologic bases for the conditions.
Developmental theories are essential in an evaluation, because expectancies change over time with increasing age and the demands in school. We know, for example, in the area of oral language, that certain phonemes occur earlier than others and that children gradually acquire more abstract vocabulary and complex syntax as they learn to read. Drawings, number concepts, and thinking skills must all be evaluated from a developmental perspective.
Theories from information processing and cognitive psychology are also used in the study of memory, metacognition, and other learning processes. Each of these perspectives provides the field with research paradigms, as well as approaches for diagnosis and intervention.
This article is devoted to descriptions of the language and educational manifestations of learning disabilities. The primary objective is to summarize the types of symptoms one might see across the age range and to highlight the relationships between various areas of learning.
Despite the heterogeneity, patterns of problems frequently co-occur.1 Rarely do we see a reading disability without spelling or written language problems. Moreover, reading problems often are related to oral language deficits, and eventually interfere with some aspects of mathematics (i.e., story problems) and other aspects of symbolic behavior such as music. Similarly, students with visual-spatial-motor problems frequently have difficulty with self-help skills, handwriting, and some components of mathematics.
Problems in listening comprehension, if severe, are among the first types of disabilities to be identified. This is because oral language development precedes other forms of symbolic behavior and because comprehension precedes expression. Children with severe listening disorders may understand only very concrete language (i.e., names of objects). Consequently, they have limited verbal expression, or they are echolalic. That is, they repeat without understanding. Some, but not all, make good use of gesture and pantomime. As a group, they are stronger visually than auditorially; but some have generalized symbolic disorders that prevent them from understanding gesture and other forms of nonverbal communication. Their strengths tend to be in areas requiring visual perception or visual spatial thinking.
Mild to moderate listening comprehension problems may, in some instances, go undetected until children enter kindergarten, when they are expected to follow specific directions, listen to stories, and learn the language of instruction. Before school entrance, they often are able to "get by" because of the contextual cues, gestures, and supports provided by adults and others in the environment. However, because school learning requires more decontextualized language, these children often come to the attention of the classroom teacher.
During the early childhood years, speech and language may be the only services available in school. Children with relatively global problems may be placed in non-categorical or developmental classes where they can receive more intensive help. Unfortunately, many schools will not, or cannot, provide services until students have a significant discrepancy between potential and achievement. Thus children with mild language learning problems may not receive services for early reading and writing difficulties until they are in late second or early third grade.
With proper intervention, students with listening comprehension problems make good progress, but often need continued intervention because the demands for higher level vocabulary and oral language increase each year in school. Children are expected to comprehend more abstract words, figurative language, complex sentences and connected discourse or lectures. As they are exposed to new course content in science, social studies, and mathematics, they also are required to understand multiple word meanings in new contexts. For example, the word symbol refers to many different concepts in mathematics, language, and music.
Often students with receptive language disorders have problems outside the classroom, because they do not understand the conversation, slang, and humor used by their peers. Those in the work place may have difficulty taking instructions or socializing with their colleagues.
Generally, listening comprehension problems are reflected in verbal expression, reading comprehension, written expression, and some aspects of mathematics. Therefore, whenever students are referred for reading comprehension problems or any other academic problem, they should have an oral language evaluation.
At times, listening problems are related to poor auditory memory span. Students may understand short units of language, but be unable to retain a series of words or sentences. Consequently they fail tasks because they cannot remember the directions.
Oral Expressive Language (Speaking)
Some students with learning disabilities have significant problems with oral expression. Like adult aphasics, they may have difficulty retrieving words, pronouncing multisyllabic words, formulating sentences, organizing their ideas, and communicating their ideas across various contexts. Many have mixed receptive and expressive disorders.
Word retrieval problems are evident when students are asked to name pictures or describe activities that require highly specific vocabulary. Often they use nonspecific words such as junk, stuff, what-cha-ma-call-it, or circumlocutions. That is, they "talk around" the topic (e.g., "the thing you sit on" instead of chair). During conversational speech, such problems are not always evident because of opportunities to point to objects or to gesture. However, whenever students are expected to access specific names, places, color words, etc., they have difficulty. This creates many problems in school when they are called upon to answer questions such as “Who discovered _____?” or “Who wrote _____?”
Word retrieval problems are also common among students with dyslexia (specific reading disabilities). Many of the same processes required for picture naming are required for reading, particularly oral reading. During the kindergarten years, such children often have difficulty saying letter names or sounds even though they can point to them correctly. When reading aloud, they may substitute semantically similar words (e.g., dress for coat), whereas other dyslexics substitute graphically similar words (e.g., coke for coat). At times, they appear dysfluent, and when placed under pressure, they manifest many symptoms of stuttering. Often, they benefit from multiple choice questions or opportunities to demonstrate their knowledge in other ways. Some read better silently and are more comfortable if they are not asked to read aloud. On the other hand, some use reading as an aid to recall.
Students with learning disabilities frequently have difficulty pronouncing multisyllabic words. Some researchers refer to this as a phonologic coding disorder because children do not always code and/or remember the sequence of phonemes in words. When asked to repeat words such as animal or domino, they distort the sequence or omit or substitute sounds. These problems can be manifested in reading; however, some students improve when they read because they are able to see the correct pattern. Generally, their spelling is seriously impaired because they cannot spontaneously recall the correct sequence of phonemes.
Many children with language learning disabilities have problems acquiring syntax. In severe cases, they will be identified during the preschool years, but those with mild, subtle problems might not be identified until they are required to formulate more precise sentences. Some use telegraphic language (e.g., "Mom me go store.") More often, research indicates that they use primarily simple sentences with few modifiers. Again, these problems may be manifested in reading, written language, and mathematics. For example, in reading, students may not be able to predict words in context because they do not have a good oral language system. In writing, they use only simple sentences, and in mathematics they may be unable to formulate number sentences even though they can solve problems.
Pragmatics refers to various communication skills and language usage in context. It includes both verbal and nonverbal communication, as well as the ability to adjust language for various audiences. Studies indicate that students with learning disabilities frequently have deficient pragmatics. Nonverbally, they may not maintain appropriate eye contact. Some use faulty prosody (inflection and rhythmic patterns of speech). Occasionally they do not maintain the appropriate vocal intensity for the context; thus, in situations where they are expected to whisper, they do not lower their voices. In conversation, some speak too loudly. Others have difficulty initiating or maintaining a conversation. They "drop the ball," cannot continue on a topic, or they change topics in the middle of a conversation.
Pragmatics also requires a "sense of audience." With maturation, experience, and informal instruction from adults, children gradually learn how to meet the needs of a listener. They adjust their language in order to communicate with children, peers, parents, or grandparents. They also adjust their language to provide the listener with the information needed to convey an idea. Again, research indicates that some students with learning disabilities have problems in this area. When asked to tell about an event, they are unable to take the perspective of the listener and therefore omit relevant details. Similar problems are evident in written language. Students write stories without providing the background, setting, characters, and other important information.
Perhaps the most common problem associated with learning disabilities is dyslexia (specific reading difficulty). Because reading is so crucial to school success, any student who is unable to read has limited strategies for acquiring knowledge in school. Although there are many reasons for reading difficulty, problems associated with learning disabilities do not result from hearing or visual problems, mental deficiency, lack of motivation, or poor instruction. Specific reading disabilities are often unexpected among children who otherwise convey intellectual curiosity and good thinking skills. Many have excellent oral language; others, however, have problems like those described previously.
Throughout the past several decades, researchers and clinicians have attempted to identify the processing deficits associated with dyslexia, such as visual perception, temporal sequencing, and cross-modal learning.2 However, Vellutino's research3 indicated that the primary deficit is in verbal coding. This is not altogether unexpected because reading is a verbal process. Nevertheless, it is necessary to define the types of verbal deficits and determine the relationship to weaknesses in phonology, syntax, morphology, semantics, and other verbal processes.
Other investigators recognized the heterogeneity among dyslexics and conducted various subgroup analyses. Although the approaches to subtyping vary with the theoretical perspective, most subtype studies revealed a preponderance of verbal rather than visual weaknesses. Nevertheless, we cannot ignore those students whose visual processing is weak.
In recent years, numerous studies have indicated that poor linguistic awareness, particularly phonologic awareness, is a core problem in dyslexia.4-6 When word recognition is used as the primary measure of reading achievement, researchers have found strong relationships between skills such as rhyming, phoneme segmentation, phoneme manipulation, and linguistic awareness. Related problems in word retrieval7 and pronunciation of multisyllabic words or nonwords further verify the verbal coding deficits.
Although these findings are important for understanding word recognition problems, many other skills are required for reading achievement. These include vocabulary, syntax, comprehension, and reasoning skills. Therefore, any study of reading disability should include much more than word recognition. It should include oral reading in context as well as comprehension of single words and context. Many studies indicate that students with learning disabilities have problems related to syntax8 and comprehension monitoring.
In addition to reading problems, some studies found that many dyslexics have problems with spatial relationships, directionality, left-right discrimination, and time orientation.9 Such deficits may be useful in differentiating dyslexia from other types of reading difficulties.
Although reading disabilities are thought to be among the most prevalent of learning disabilities, in reality, those related to written expression are more frequent. This is due, in part, to the fact that reading is essentially a form of receptive language, whereas writing is expressive. Typically, a disorder of input interferes with output. Some professionals use the term dyslexia more broadly, so that it refers to a spelling disorder, not just reading. Others, however, use the term dyslexia only for reading disabilities. In any case, children and adults with learning disabilities have various writing problems,10 including handwriting, spelling, written syntax, and formulation of discourse.
Handwriting problems are usually visible and readily identifiable. Severe problems may be noted even during the kindergarten years. Often, however, professionals believe that young children should not be labeled because of maturational and developmental factors. They want to make certain the delays are not simply related to developmental variations. Nevertheless, persistent handwriting problems are evident among many school children and adults with learning disabilities. Typically, the poor hand writers also have difficulty with other types of visual-spatial learning, including some aspects of mathematics, drawing, and various self-help skills such as learning to tie shoes, riding bikes, playing sports, or driving a car. As indicated previously, problems often co-occur and should be identified in order to meet the overall needs of the student.
Spelling problems abound, but they vary with the nature of the problem. Students with phonologic awareness problems often omit sounds or syllables and write words nonphonetically (e.g., imptat for important). Those with good phonologic awareness represent all of the sounds, but may have limited orthographic awareness or visual memory. Therefore, they write words as they sound (e.g., deside for decide and fashun for fashion). Others fail to acquire the morphographemic rules and do not attend to the base words. Therefore, they may write desizhun for decision.11 Still others make mistakes because of faulty monitoring and attention. They know how to spell, but during the complex process of writing, they add, omit, or substitute letters.
Research indicates that many students with learning disabilities have problems with written syntax. In certain instances, they use correct grammar, but their sentences are very simple. At other times, accuracy is a major factor. These problems may be related to oral language deficits; others, however, occur only in writing. Often, as in spelling, students fail to monitor their errors and cannot think about several rule systems simultaneously.
Finally, problems related to written text organization have been identified in both clinical and empirical studies. Students with learning disabilities often have difficulty generating ideas, organizing text, using cohesive devices (e.g., “next” and “although”), and selecting relevant information. Such difficulties can be related to basic language or reading problems; others are related to executive functions such as planning and attending. In other cases, students have not been taught systematic revision procedures. Thus, their written work contains many errors. Despite the large number of mechanical, spelling, and grammatical mistakes, studies indicate that at least some students with learning disabilities have very interesting ideas to convey. Their problems are not with ideation or the functions of writing, but with the proper forms, including spelling and mechanics.
Mathematics has not always received sufficient attention in the evaluation and intervention of students with learning disabilities, probably because most people feel that reading and writing are more important. Studies of adults, however, indicate that persistent mathematical problems can interfere with educational, vocational, and social mobility. Therefore, an evaluation of both computation and reasoning is needed. All too often, only quick screening measures of computation are conducted.
Mathematics, like other forms of symbolic behavior, can be impaired for various reasons, including faulty instruction, anxiety, lack of motivation, and overall lower intelligence. Even within the population of students with learning disabilities, various problems can be identified.
Students with reading disabilities may or may not have computation problems. Unlike reading, mathematics does not require a high degree of phonologic awareness. The referent for numbers is more stable. On the other hand, some students have global symbolic deficits, so both reading and mathematics are deficient.
Mathematics problems often result from oral language deficits. Students who fail to understand multiple word meanings or complex syntax frequently have difficulty with story problems. Those with word retrieval difficulties have problems with quick recall of numbers and must repeat entire number sequences before they can say a specific number.
Other students have visual-spatial problems that interfere with handwriting as well as mathematics. Some cannot count systematically or visualize sets of figures. Others cannot align numbers properly. In higher mathematics, they have difficulty with geometry, fractions, estimation, and other skills that require visual-spatial thinking.
Problems pertaining to logical thinking and reasoning may interfere with mathematics. Students with these difficulties may memorize mathematics facts, but they perform poorly on Piagetian conservation tasks and other measures that require logical thinking.
Memory deficits are prevalent. Parents and teachers report that students with learning disabilities are unable to learn the mathematics facts even though they understand the operations. Consequently, they have difficulty in situations where they cannot use calculators. Nevertheless, their problems are of less concern than those with faulty logic.
Finally, studies have indicated that students with learning disabilities may be strategy deficient. They do not use good problem-solving strategies. Even in adulthood, they may count on their fingers. Others have no systematic plan for working complex problems.
Nonverbal Disabilities and Social Skills
The current federal definition of learning disabilities does not include nonacademic disorders, but some early ones included nonverbal problems such as spatial orientation, and recent definitions include social skills.12 Although considerable attention has been given to social skills in recent years, the bases for those problems are not well described. As indicated above, some social problems may be related to oral language difficulties, particularly pragmatics and the comprehension and production of prosody (i.e., the inflectional and rhythmic patterns of language that convey emotion).
Other social perception problems arise because of an inability to perceive another person’s point of view. Often these are related to general reasoning and cognitive deficits.
More often, however, social problems have been associated with high verbal and low performance intelligence profiles. People with this pattern frequently have the same types of problems as those with right-hemisphere disorders.9, 13 They fail to interpret and/or use multiple forms of nonverbal communication, including body language, gesture, facial expression, proxemics (the distance cues that convey meaning), and prosody.
Visual-spatial weaknesses are also prevalent among students with nonverbal disorders. These result in faulty spatial orientation, an inability to judge distances, and a host of skills required for daily living. These problems may interfere with early reading skills and some aspects of mathematics, geometry, chemistry, and anatomy.
When studying nonverbal problems, it is necessary to consider many types of nonlinguistic symbols including picture interpretation, symbolic play, all types of nonverbal communication, graphs, maps, signs and other figures that are used in the environment and in various school subjects.
Although nonverbal problems interfere with certain facets of academic learning, most often they interfere with nonacademic skills such as play and social interaction. In adulthood, they often create problems in daily living and in the workplace.
In general, people with learning disabilities are a heterogeneous population that require a multidisciplinary evaluation and careful, well-planned intervention. Despite this heterogeneity, patterns of problems often co-occur. Therefore, diagnosticians and educators should look beyond single areas of achievement such as reading or arithmetic. In addition, problems in one area of learning typically have secondary impacts on higher levels of learning. That is, comprehension problems typically interfere with expression. Every effort should be made to examine patterns of problems and to avoid fragmentation of services so that each area of underachievement is not treated separately.
Although learning disabilities usually interfere with school performance, they are not simply academic handicaps. They interfere with certain social activities as well as occupational pursuits. In many instances, they impact on mental health and self-esteem. Therefore, students need multiple services. And, as emphasized throughout this journal issue, learning disabled individuals may have comorbid conditions such as attention deficit disorder, depression, and neurologic problems. Furthermore, the problems may change over time. Children may first be identified because of language comprehension problems but later have reading or mathematics difficulty. With intervention, oral expressive problems may be alleviated, but may be manifested later in written language.
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Reprinted from the Journal of Child Neurology, Volume 10, Supplement Number 1, January 1995, p. S2-S5. Permission for reprint granted by Jean Petersen, Executive Director, LDA of America. This article may not be reprinted in any form.
Doris J. Johnson, Ph.D. is the JoAnn and Peter Dolle Professor of Learning Disabilities in the School of Communication at Northwestern University.