Neuropsychological impairment in Duchenne muscular dystrophy.

Fourteen younger (ages 6 to 10 years) and 11 older (ages 11 to 16 years) Duchenne Muscular Dystrophy (DMD) patients were tested with the WISC-R and neuropsychological language, visual-motor, and motor tasks. Older boys had an average IQ; younger boys were in the low average IQ range. Younger DMD boys were inferior to the older DMD group on tasks requiring some language and attentional-organizational skills, but not on visual-motor tasks. Older DMD boys were inferior on motor tasks. Results suggest that the reported low cognitive skills in DMD patients are not fixed or global, but reflect selective deficits in the younger boys. Possible bases for age differences in performance are discussed.