Rhythmic and circadian light therapy for mild cognitive impairment in Alzheimer's disease

Participants will randomly be placed into one of four groups and experience one of the four following conditions: (1) a placebo light that provides a 40 hertz (Hz) flicker (rhythmic light [RL]); (2) a placebo light with a random flicker (placebo condition for rhythmic light); (3) a light source that will stimulate the circadian system and provides a 40 Hz flicker (RL); or (4) a light source that will stimulate the circadian system and provides a random flicker (placebo condition for rhythmic light). Following a baseline week, participants will experience his/her assigned lighting condition for two hours in the morning for 8 weeks. After a 4-week washout period, a final round of assessments will be obtained. Study assessments (except for the Pittsburgh Sleep Quality Index and Montreal Cognitive Assessment) will be collected at the end of each week, for a total of 8 assessments.