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Journal Issue: Special Education for Students with Disabilities Volume 6 Number 1 Spring 1996

Learning Disabilities
G. Reid Lyon

Co-occurring Disorders

As noted, most children with learning disabilities have more than one of the seven subtypes of learning disabilities. It is also not unusual to find LD co-occurring with certain behavioral or emotional disorders. The most common co-occurring combinations are discussed briefly below.

Reading and Attention Disorders

Attention deficit disorder (ADD) is an increasingly common diagnosis recognized in medicine47 and psychology17 although it is not a category of disability recognized under the IDEA. Like LD, ADD is the subject of considerable controversy, and diagnostic criteria for ADD continue to evolve. There is no litmus test for ADD, which is diagnosed on the basis of persistent and maladaptive behavior patterns (inattention, impulsivity, and hyperactivity) that are inappropriate for the child's age. The number of diagnoses of ADD has increased dramatically in the past decade,48 and one study12 found 7% of a survey sample of 445 kindergarten students qualifying as "inattentive" on the Multigrade Inventory for Teachers.

Figure 212 indicates that a child identified with reading disabilities is twice as likely as a member of the general population to also meet the diagnostic criteria for inattention (15% versus 7%). Similarly, an individual diagnosed with ADD is at higher risk than a member of the general population of having a reading disability/phonological awareness deficit (36% versus 17%). Despite this co-occurrence, recent studies have indicated that reading disabilities and ADD are distinct and separable disorders.12,22.49

Unfortunately, when children with disabilities in reading also manifest ADD, their reading deficits are typically exacerbated, more severe, and more resistant to intervention.22 In contrast to reading disabilities, ADD is more prevalent in males. Given the frequent co-occurrence of ADD with reading disabilities and given the tendency of boys with ADD to attract considerable attention from teachers, this combination may make boys with disabilities in reading much more likely than girls with disabilities in reading to come to the attention of teachers and to be referred for testing.

Social Adjustment Problems

In a broad sense, data indicate that learning disability, no matter what the specific type, has a tendency to co-occur with social adjustment problems.50 Bruck,51 in her review of the literature related to social and emotional adjustment, concluded that children with learning disabilities are more likely to exhibit increased levels of anxiety, withdrawal, depression, and low self-esteem compared with their nondisabled peers. This comorbidity is persistent. For example, Johnson and Blalock52 found that, of the 93 adults studied in an LD clinic sample, 36% continued to receive counseling or psychotherapy for low self-esteem, social isolation, anxiety, depression, and frustration. In many instances, it appears that such emotional problems reflect adjustment difficulties resulting from academic failure.13 Deficits in social skills have also been found to exist at significantly high rates among children with learning disabilities.53 In general, social skill deficits include difficulties interacting with people in an appropriate fashion (for example, lack of knowledge of how to greet people, how to make friends, and how to engage in playground games or a failure to use knowledge of such skills in these situations). While not all children with learning disabilities exhibit deficits in social skills, there are certain common characteristics among those who do. For example, Bruck51 reported that children with more severe manifestations of LD are likely to manifest both an increased number of and increased severity of social skills deficits. Moreover, the gender of the child appears to be a factor, with evidence suggesting that girls with LD are more likely to have social adjustment problems.51

Reading Disorders with Other Learning Disabilities

There is abundant evidence that it is rare for a child with learning disabilities to manifest only one specific type of learning disability.3,53 The co-occurrence of learning disorders should be expected given the developmental relationships between listening, speaking, reading, spelling, writing, and mathematics. For example, it is clear that deficits in phonological awareness lead to difficulties in decoding and word recognition which, in turn, lead to deficits in reading comprehension.16,37,38 Likewise, children with disabilities in reading frequently experience persistent difficulties in solving word problems in math for the obvious reason that the printed word is difficult for them to comprehend.14

An important conclusion to draw from the literature on co-occurring disorders is that any intervention or remediation effort must take into account the range of deficits a child may have. More specifically, while an intensive reading intervention may consist of explicit instruction in phonological awareness, sound-symbol relationships, and contextual reading skills, the child may also require elements essential to bolstering self-esteem, and to fostering reading in other content areas such as mathematics, social studies, and science. One cannot expect the intervention for the reading deficit to generalize serendipitously to other domains of difficulty.

LD in Written Expression

Typically, children who display LD in written expression have difficulties in spelling, formulation and expression of ideas, handwriting, and knowledge of grammar and syntax. Unfortunately, well-designed research investigating disorders of written expression is relatively meager. Definitions for disorders of written expression remain vague.54 Therefore it is not surprising that estimates of the prevalence of such disorders range from 8% to 15%.13 What is known is that boys and girls display written language deficits at relatively equal rates.54 Despite the lack of objective and detailed identification criteria, a number of excellent studies have been conducted to identify effective assessment and intervention programs for problems in written expression.55-57

The most successful programs tend to ensure that clear linkages are drawn between oral language, reading, and written language. Successful programs also ensure that basic skills development in spelling and writing (graphomotor production) are explicitly taught and/or accommodated and that the student is also taught how to employ strategies to guide the formulation of ideas for writing and the organization of these ideas in writing. These elements are common to many writing programs; however, successful instruction for students with disabilities in written expression depends upon their intensity and explicitness.

LD in Mathematics

Children identified as manifesting LD in mathematics can demonstrate deficits in arithmetic calculation, mathematics reasoning, or both. In general, authorities agree that approximately 6% of the school population have difficulties in mathematics that cannot be attributed to low intelligence, sensory deficits, or economic deprivation.14,58 While the data are sparse at this time, it appears that deficits in arithmetic calculation skills are more frequently identified than deficits in arithmetic reasoning.14 However, common sense would suggest that attempts to reason mathematically would be constrained by limitations in calculations skills. Unfortunately, a major difficulty in identifying math learning disabilities accurately is that, like learning to read, learning mathematics concepts is dependent upon the teacher's knowledge of the concepts and ability to present them.13