Abstract
BACKGROUND: Impairment in activities of daily living is a major burden for Alzheimer's disease dementia patients and caregivers. Multiple subjective scales and a few performance-based instruments have been validated and proven to be reliable in measuring instrumental activities of daily living in Alzheimer's disease dementia but less so in amnestic mild cognitive impairment and preclinical Alzheimer's disease. OBJECTIVE: To validate the Harvard Automated Phone Task, a new performance-based activities of daily living test for early Alzheimer's disease, which assesses high level tasks that challenge seniors in daily life. DESIGN: In a cross-sectional study, the Harvard Automated Phone Task was associated with demographics and cognitive measures through univariate and multivariate analyses; ability to discriminate across diagnostic groups was assessed; test-retest reliability with the same and alternate versions was assessed in a subset of participants; and the relationship with regional cortical thickness was assessed in a subset of participants. SETTING: Academic clinical research center. PARTICIPANTS: One hundred and eighty two participants were recruited from the community (127 clinically normal elderly and 45 young normal participants) and memory disorders clinics at Brigham and Women's Hospital and Massachusetts General Hospital (10 participants with mild cognitive impairment). MEASUREMENTS: As part of the Harvard Automated Phone Task, participants navigated an interactive voice response system to refill a prescription (APT-Script), select a new primary care physician (APT-PCP), and make a bank account transfer and payment (APT-Bank). The 3 tasks were scored based on time, errors, and repetitions from which composite z-scores were derived, as well as a separate report of correct completion of the task. RESULTS: We found that the Harvard Automated Phone Task discriminated well between diagnostic groups (APT-Script: p=0.002; APT-PCP: p<0.001; APT-Bank: p=0.02), had an incremental level of difficulty, and had excellent test-retest reliability (Cronbach's α values of 0.81 to 0.87). Within the clinically normal elderly, there were significant associations in multivariate models between performance on the Harvard Automated Phone Task and executive function (APT-PCP: p<0.001), processing speed (APT-Script: p=0.005), and regional cortical atrophy (APT-PCP: p=0.001; no significant association with APT-Script) independent of hearing acuity, motor speed, age, race, education, and premorbid intelligence. CONCLUSIONS: Our initial experience with the Harvard Automated Phone Task, which consists of ecologically valid, easily-administered measures of daily activities, suggests that these tasks could be useful for screening and tracking the earliest functional alterations in preclinical and early prodromal AD.