Age-related neuropsychological deficits in Down's syndrome.

Down's syndrome (DS) has been suggested as a high-risk condition for Dementia Alzheimer's type (DAT). In the present study, neuropsychological variables were assessed in 165 DS subjects and 163 matched mentally retarded controls. Overall, DS subjects had lower scores for orientation, digit span, visual memory, object-naming, and general knowledge, as well as more "released" reflexes. Impairments were most evident in DS subjects greater than 50 years old. These findings provide further support for an association between aging and DAT in Down's syndrome. Methodological issues and areas for future research are discussed.