Current studies concerning the co-occurrence, of attention deficit disorder and one or more learning disabilities are examined. Information is reported from four major aspects of the research: (a) statistical accounts of the prevalence of attention deficit disorder and the simultaneous occurrence of the two disorders; (b) subtypes of attention deficit disorder as they relate to learning disabilities; (c) findings and suggestions as to causes for the co-occurrence; and (d) educational implications based on current research.
Research acknowledges that learning disability and attention deficit disorder (ADD) frequently co-occur. In addition to significant inattentiveness, impulsivity, and hyperactivity, primary characteristics manifested in children diagnosed as ADD include "learning disorder" and "academic underachiever" (Marshall & Hynd, 1997; Stanford & Hynd, 1994). Estimates of co-morbidity of ADD and learning disability range from approximately 20% (Javorsky, 1996) to approximately 50% (Riccio & Jemison, 1998). Estimates of reports vary, depending on the way learning disability is defined or ADD is assessed. While this rate of co-occurrence has led some to theorize that the two disorders share overlapping deficits (Marshall & Hynd, 1997), other research concludes that ADD and learning disability are separate and distinct entities that often co-occur (Riccio & Jemison, 1998).
The purpose of this paper is to review the contemporary literature related to the cooccurrence of attention-deficit disorder (ADD), with and without hyperactivity, and specific learning disabilities. Factors common to children with either learning disability or attention deficit disorder as compared to common features of children diagnosed as having both ADD and learning disability are presented.
Attention deficit disorder occurs in an estimated 3 to 5% of school age children and is one of the most frequent reasons children are referred for evaluation (Stanford & Hynd, 1994). ADD was originally considered as "minimal brain dysfunction" and thus related to learning disability (Riccio & Jemison, 1998). However, the American Psychiatric Association (APA) gradually recognized it as a behavioral disorder separate from the developmental learning disabilities. The APA has recently further described the disorder as having subtypes: predominantly inattentive (or without hyperactivity), predominantly hyperactive, and combined type (Riccio & Jemison, 1998).
Stanford and Hynd (1994) found that Children with ADD have been found to be more disabled academically and cognitively than those without ADD. The disorder, which often occurs with learning disabilities, appears not only to have a negative effect on school achievement, but limits functional ability in other environments as well. While some studies have indicated an overlap in the area of attention between ADD and learning disability relative to cognitive behavior, their research did not support such an overlap in the behavioral domain.
Stolzenberg and Julkowski (cited in Marshall & Hynd, 1997) hypothesized that children with ADD experience difficulty decoding in reading and computing in math because working memory problems based on attention, interfere with absolute symbol systems necessary to these skill areas. Zentall and Ferkes (cited in Riccio & Jemison, 1998) expressed the view that inattention and disorganization, which relate to cognitive style, contribute to math computation deficiency. On the other hand, decreased IQ, memory, and reading ability seem to correlate with comprehension in reading and problem solving. Of interest are the findings that the cognitive tasks that are often predictive of reading disability have been found to be deficient in individuals with ADD. Among such tasks are naming, perceptual speed, and speed of cognitive processing (Marshall & Hynd, 1997). While lack of proficiency in these tasks has been shown to be predictive, Wood and Felton (cited in Riccio & Jemison, 1998) found attention variables themselves not to predict reading achievement. …