The purpose of this preliminary report was to explore overall level and diurnal patterning of caregiver reports of abnormal behavior and to explore relationships with actigraphic measures of sleep/wake activity in Alzheimer's disease (AD) patients. Our primary behavioral measure was the Time-based Behavioral Disturbance Questionnaire (TBDQ). The overall score on this measure was shown to have adequate test-retest reliability and convergent validity with another behavioral measure. Significant correlations were obtained between the TBDQ overall score and actigraphically scored sleep efficiency (r = -.35, P < .05) and wake after sleep onset (r = .43, P < .01) in 41 subjects. The data suggest a moderate relationship between actigraphic measures of sleep/wake and disturbed behavior in home-dwelling AD patients.