MEMORY, LANGUAGE, AND PRAXIS IN ALZHEIMERS-DISEASE - NORMS FOR OUTPATIENT CLINICAL-TRIAL POPULATIONS

The cognitive subscale of the Alzheimer's Disease Assessment Scale (AD AS-Cog) is designed specifically to assess memory, language, and praxi s dysfunctions characteristic of Alzheimer's disease (AD), In this rep ort, we use data from 1,648 AD participants in two identical 26-week m ulticenter drug trials to derive clinical trial population-based norms for ADAS-Cog subtest scores. All 11 ADAS-Cog item scores were sensiti ve to differences in dementia severity judged either by baseline Mini- Mental State Exam (MMSE) scores or by Global Deterioration Scale (GDS) stage of dementia, Using ADAS-Cog subtest scores alone, 85 percent of GDS 4 subjects and 69 percent of GDS 5 subjects could be classified c orrectly, In a stepwise discriminant analysis, orientation was the ite m with the greatest discriminatory power between subjects with GDS 4 a nd GDS 5 stages of dementia, ADAS-Cog subtest scores also varied by ag e, gender, educational level, and concurrent use of anti-inflammatory drugs or estrogen (in women). Such normative data may facilitate the s election of appropriate outcome measures to investigate differential t reatment effects on specific cognitive domains or in specific AD subpo pulations.