Precocious aging and dementia in patients with Down's syndrome.

Fifty unselected institutionalized patients with Down's syndrome were studied to determine the clinical course of precocious aging and mental and neurological deterioration. In our studies we establish statistically significant differences in neurological and psychiatric abnormalities and mental deterioration in patients below and above age 35, indicating progressive changes in the central nervous system. We demonstrate higher incidence of recent memory loss, impairment of short-term visual retention, frontal release signs, hypertonia, hyperreflexia, long-tract signs, and psychiatric problems. We also note the presence of external features of precocious aging. Down's syndrome appears to be a human chromosomal abnormality in which genetically determined biochemical defects leading to precocious aging and dementia can be studied.