Arithmetic disabilities and ADD subtypes:: Implications for DSM-IV

This study investigated whether specific academic deficits were associated with attention-deficit disorder (ADD) subtypes. Twenty students (ages 8-12) with attention-deficit disorder with hyperactivity (ADD/H) were compared to 20 students with attention-deficit disorder without hyperactivity (ADD/noH). Group differences were compared using a MANCOVA, and paired t tests were used to compare within-group differences. Dependent variables for the within-group differences were four achievement subtest scores from the Woodcock-Johnson Psyche-Educational Battery-Revised: Letter-Word Identification, Passage Comprehension, Calculation, and Applied Problems. Consistent with much of the previous research, no significant between-group differences were found on the achievement measures. Significant differences did, however, appear in the six within-group comparisons, all involving lower performance on the Math Calculations subtest. For students with ADD/H, only one comparison (with Math Applied Problems) reached significance. Students with ADD/noH, however, had significantly lower scores on the Calculation subtest compared to all of the other achievement subtests. These results provided additional support for the hypothesis that inattention exerts a specific and deleterious effect on the acquisition of arithmetic computation skills. These findings have important implications for the diagnosis and treatment of ADHD as conceptualized in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV; American Psychiatric Association, 1994), because they suggest that students with ADHD-Predominantly Inattentive Type may be at increased risk for arithmetic calculation deficits.