ALZHEIMER-DISEASE ASSESSMENT SCALE - A SUBTEST ANALYSIS

The Alzheimer Disease Assessment Scale (ADAS) was administered to 61 A lzheimer patients, 52 elderly controls, and 80 controls between age 7 and 54 years. The Alzheimer group was categorized into different sever ity levels of dementia based on MMSE scores: very mild (greater-than-o r-equal-to 24), mild (greater-than-or-equal-to 20), moderate (10-19), and severe (0-9). All 11 ADAS Cognitive subtest scores for the mild, m oderate, and severe dementia groups were statistically worse than the elderly control group. This was also the case for the very mild group, except for Naming, Commands, Constructional Praxis, and Ideational Pr axis. In terms of magnitude of effect, memory and spontaneous language items were the earliest indicators on the ADAS, while praxis, command s, and naming items were only sensitive later in the course of the dis order. The best single indicators of progression throughout the severi ty continuum of dementia (i.e., from normal to severe) were the Orient ation subtest, the ADAS Cognitive score, and the ADAS Total score. The ADAS Noncognitive subtests generally did not show the progression wit h increasing dementia that was evident on the ADAS Cognitive subtests. Differences in educational level had no statistically significant eff ects on any of the ADAS subtest scores, and age differences were few a nd small in magnitude. The differential rate of decline of the various ADAS subtests appears to reflect both the changing pattern of cogniti ve impairments as a function of severity of DAT and also to some exten t the psychometric limitations of some of the subtests.