Longitudinal course of normal aging and progressive dementia of the Alzheimer's type: a prospective study of 106 subjects over a 3.6 year mean interval.

Elderly, community residing subjects (N = 106; mean age = 70.6 +/- 6.02 years) with cognitive functioning consistent with normal aging or dementia of the Alzheimer's type (DAT), were followed over a 3.6 year mean interval (range = 2.78 to 5.12 years). All subjects were assessed at baseline on the Global Deterioration Scale (GDS), a global clinical instrument reflecting the continuum of cognitive dysfunction from normal aging to severe DAT. At follow-up subjects were reassessed with respect to mortality, institutionalization and clinical change, defined as at least a two-point change on the 7-point GDS. Our results suggest that patients at deterioration levels GDS greater than or equal to 4, are more likely to show negative outcomes, specifically, institutionalization (Ps less than .001), death (Ps less than .01), or, for the community residing remainder, clinical deterioration (Ps less than .05), than subjects from less impaired (GDS = 2 or GDS = 3) subject groups. Seventy-six per cent of subjects at deterioration levels four or greater (N = 34) had negative outcomes at follow-up, whereas ninety percent of subjects with deterioration levels less than four (N = 72) did not.