Dementia of the Alzheimer's type and accelerated aging in Down syndrome.

This case study, of a woman with Down syndrome and dementia of the Alzheimer's type (DAT), follows the course of her decline over an 11-year period until death at age 57. Detailed neuropathological findings are also presented. This case illustrates features of premature aging that are typically associated with Down syndrome, and the progressive changes in memory and cognition that are usually associated with DAT. Although the subject's cardiovascular condition and thyroid disorder were treated, they may have contributed to the decline of her memory. This case shows the difficulty in diagnosing dementia in an individual with mental retardation who suffered comorbid episodes of depression and psychosis.