INITIAL PILOT VALIDATION OF AN ELECTRONIC ALZHEIMER’S DISEASE ASSESSMENT SCALE–COGNITIVE SUBSCALE (EADAS-COG): RATIONALE AND METHODS

Abstract

The Alzheimer’s Disease Assessment Scale (ADAS) was developed to provide a measure of change in the cognitive and behavioral functions known to be impaired by Alzheimer’s disease. Over the last 20 years, the cognitive subscale, (ADAS-Cog), has become the de facto gold-standard for assessing the efficacy of putative anti-dementia treatments, serving as the primary or co-primary outcome for nearly all phase 2 and phase 3 drug development trials. Given its importance to therapeutic development, there has also been an increasing interest in providing greater standardization, automation, and administration consistency of the scale. Recently, computerized versions of the ADAS-Cog (eADAS-Cog) have begun to be utilized in clinical trials. While the eADAS-Cog has been purported to be equivalent to paper in terms of validity, to date, there has not been a prospective trial comparing a version of the eADAS-Cog with the paper in a clinical population. We will conduct a single-center, randomized, counterbalanced, prospective trial of a version of the eADAS-Cog in comparison to the paper version of ADAS-Cog (11 item) in men and women ages 50-90 (inclusive) meeting NI-AA criteria for mild to moderate Alzheimer’s disease. Twenty-five subjects will be enrolled. Subjects who meet inclusion criteria will be randomized to one of two study conditions associated with the alternating order in which they will receive study measures (ADAS-Cog vs eADAS-Cog). Subjects will return for two subsequent visits at 2 week intervals at which time they will repeat study assessments. We will investigate the concurrent validity of an eADAS-Cog vs. the paper version using Interclass Correlation Coefficients and individual t-tests. Longitudinal test-retest reliability between study administrations will be evaluated separately for each mode of administration. As electronic versions of validated paper measures become more widely utilized as primary outcome measures in clinical trials, establishing concurrent validity between modalities remains a paramount issue.