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

Simple and complex visuomotor performance of the right and left sides of the body was investigated in 37 children with left hemisphere lesions, 35 children with right hemisphere lesions, 53 developmentally dyslexic children, 29 developmentally hyperactive children, and 35 "normal" children who had endured a very mild head injury with no sequelae.

Lateralized soft signs, EEG topography, metabolic brain imaging, and neuropsychological test profiles suggest a predominance of left hemisphere dysfunction in dyslexia and right hemisphere dysfunction in hyperactivity.

Nine 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.

The children with left hemisphere lesions manifested significantly weaker performance on test components involving the right body side, relative to the normal controls, on the Purdue pegboard, Rey complex figure (delayed recall condition), and WISC Picture completion tests, and the dyslexic children on the former two. The children with right hemisphere lesions manifested significantly weaker performance on test components involving the left body side, relative to the normal controls, on the WISC Mazes test, as did the hyperactive children.

We propose that (1) contralateral performance decrement results from a unilateral cortical lesion in children, and (2) developmental dyslexia may comprise a slight predominance of left hemisphere dysfunction and developmental hyperactivity of right hemisphere dysfunction.