The occurrence of Alzheimer's disease (AD) is growing, with 68% of cases occurring in women. Declines in global function exacerbated by reversal of day-night patterns, disturbed sleep-wake rhythms, and excessive daytime sleepiness make managing AD difficult. In this study, the authors examined the effect and duration of effect of therapeutic light on sleep, rest-activity, and global function in women with AD using mixed methods in a two-group experimental design with repeated measures on one factor. Twenty women with AD were randomized to experimental or control conditions. Blue-green or dim red light was delivered via cap visor in the morning. Results of the qualitative analysis of serial interviews with family and facility caregivers regarding perceived effect of light on global function are presented. Themes emerged in both groups with respect to cognition and psychosocial function. Future studies with larger samples using quantitative measures of global function are warranted to verify findings.