Rhythmic Light Therapy for Alzheimer's Disease Patients

The investigator will investigate how light delivering 40 hertz (Hz) affects subjective sleep and cognition in a controlled laboratory study. A lab study will allow the collection of electroencephalogram (EEG) data, perform cognitive tests, and observe the response in those with mild cognitive impairment (MCI) compared to a healthy control group (HC). Participants will attend two study sessions over the course of two weeks. During both sessions, all participants will experience 10 minutes of a low-level light, followed by a data collection period which involves a sleepiness rating, an electroencephalogram (EEG) recording, and a computerized memory test. Participants will then experience either a RL or a placebo RL condition for one hour, after which there will be a second data collection.