The association of specific academic deficits with attention deficit disorder (ADD) subtypes was determined in 20 students (ages 8-12) with ADD with hyperactivity (ADD/H) compared to 20 with ADD without hyperactivity (ADD/noH), at the Department of Educational Psychology, University of Texas at Austin, TX. Using subtests of the Woodcock-Johnson Psycho-Educational Battery-Revised to determine group differences, scores for students with ADD/noH were significantly different on four of seven measures, and the Calculation subtest scores were significantly lower when compared to all other achievement subtests. By contrast, for students with ADD/H, no significant differences were found in six of seven analyses, although their Calculation subtest scores were lower than scores on the Applied Problems subtest. These results support the hypothesis that inattention has a specific and adverse effect on arithmetic computation skills. 
COMMENT. Students with ADHD-Predominantly Inattentive Type are at increased risk for arithmetic calculation deficits. These findings have important implications for the diagnosis and treatment of ADHD and the recognition of ADHD subtypes as defined by the DSM-IV criteria. Children with ADD-inattentive type should also be examined for Gerstmann syndrome.
Gerstmann syndrome. Profound developmental dyscalculia and Gerstmann syndrome may occur in children with ADHD. Deficits in specific cognitive areas may involve visuo-spatial perception and parietal-occipital function . Confirmation of the essential visuospatial origin and impaired mental manipulation of images is described in “a pure case of Gerstmann syndrome with a subangular lesion“ . An adult presenting with the four characteristic symptoms (finger agnosia, agraphia, right-left disorientation and dyscalculia), in the absence of any other neuropsychological disorders, had a focal ischemic lesion in the inferior left angular gyrus, extending to the callosal fibers. An impairment in mental manipulation of images and visuospatial function is the basis for the Gerstmann cognitive deficit syndrome.