Interactive effects of age and cerebral disease on cognitive performances.

A battery of mental tests was given to groups of younger (16--44 years) and older (48--60 years) control and cerebral diseased patients. Each patient in the younger cerebral diseased group was matched individually with an older cerebral diseased patient for type and site of lesion. Each patient with cerebral disease was matched individually with a control patient for age, educational level and sex. Differences in level of test performance related to age were generally greater for cerebral diseased than for control patients. Differences in level of test performance related to diagnostic category were generally greater for older than for younger patients. Analysis disclosed a significant overall interactive effect of age and cerebral disease on the performance of mental tests, supporting the hypothesis that acquired cerebral disease has more severe behavioral consequences in older than in younger persons.