Right body side performance decrement in congenitally dyslexic children and left body side performance decrement in congenitally hyperactive children

Objective: Simple and complex visuomotor performance of the right and left sides of the body was investigated in 37 children with left hemisphere lesi ons. 35 children with right hemisphere lesions, 53 developmentally dyslexic children, 29 developmentally hyperactive children, and 35 "normal" childre n who had endured a very mild head injury with no sequelae. Background: Lat eralized soft signs, EEG topography, metabolic brain imaging, and neuropsyc hological test profiles suggest a predominance of left hemisphere dysfuncti on in dyslexia and right hemisphere dysfunction in hyperactivity. Method: N ine measures of lateralized performance were drawn from the Purdue pegboard , Letter cancellation, Rey complex figure, Wechsler Intelligence Scale for Children (WISC) Mazes, and WISC Picture completion tests. Results: The chil dren with left hemisphere lesions manifested significantly weaker performan ce on test components involving the right body side, relative to the normal controls, on the Purdue pegboard, Rey complex figure (delayed recall condi tion). and WISC Picture completion tests, and the dyslexic children on the former two. The children with right hemisphere lesions manifested significa ntly weaker performance on test components involving the left body side, re lative to the normal controls, on the WISC Mazes test. as did the hyperacti ve children. Conclusions: We propose that(1) contralateral performance decr ement results from a unilateral cortical lesion in children, and (2) develo pmental dyslexia may comprise a slight predominance of left hemisphere dysf unction and developmental hyperactivity of right hemisphere dysfunction.