FREQUENCY OF HIPPOCAMPAL-FORMATION ATROPHY IN NORMAL AGING AND ALZHEIMERS-DISEASE

We used CT and MR to examine the frequency of occurrence of hippocampa l formation atrophy (HA) in a research clinic population of 130 normal elderly, 72 nondemented patients with very mild memory and cognitive impairments (MCI), 73 mild Alzheimer's disease (AD) patients, and 130 patients with moderate to severe AD. HA was found in 29% of the normal elderly group and its frequency of occurrence was strongly related to increasing age. For normal elderly 60-75 years of age, 15% had HA; th e proportion rose to 48% in subjects 76-90 years of age. Among the thr ee groups of impaired patients, the frequencies of HA ranged from 78% in the MCI patients to 96% in the advanced AD group. Unlike the normal elderly group, the percentages were not related to age. In both the n ormal elderly group and MCI group disproportionately more males than f emales had HA. After controlling for learning and the effects of gener alized brain changes as reflected in ventricular size, only in the nor mal group was KA associated with reduced delayed verbal recall perform ance. Follow-up examinations for 15 individuals with baseline HA, 4 wh o at entry were MCI and 11 probable AD, yielded clinical and neuropath ologic diagnoses of AD in all cases. The results of the present study indicate that hippocampal formation atrophy is associated with memory and cognitive impairments. Further longitudinal and neuropathologic wo rk is required to validate the relationship between hippocampal format ion atrophy and AD. Copyright (C) 1996 Elsevier Science Inc.