Neuropsychological aspects of multiple sclerosis.

Twenty-six persons (five males and 21 females) with the neurological diagnosis of multiple sclerosis, and an equal number of control subjects matched on age, sex, and education were given a battery of tests designed to assess motor and intellectual functioning. Subjects in the multiple sclerosis group displayed marked deficits on all tests of motor skill except grip strength. Although verbal intelligence was not impaired in subjects with multiple sclerosis, these subjects performed more poorly than control subjects on two different tests of memory even though these tasks required minimal motor responsivity. Correlational analyses on the several motor and cognitive tasks revealed that correlations between motor and memory performance were consistently higher in persons with multiple sclerosis than in controls. These results suggest that whereas multiple sclerosis may not have mch effect on the utilization of stored verbal information, the processing and storage of new verbal material are disrupted by the disease to a degree that is paralleled by the extent of motor impairment. This finding is consistent with the view that the memory impairments observed are secondary to the primary motor deficit, but the alternative explanation that memory functions, like motor functions, are especially vulnerable to the demylination process of multiple sclerosis is equally viable at present.