Subjects will be enrolled in the study for 26 weeks. During the first week, subject will come in to Mount Sinai for a study visit to complete a few questionnaires about sleep and mood, complete several memory tests and have an MRI of their brain. These study visits will take about 2 hours to complete. During this week, subject will also be asked to wear a wrist actigraph and light meter for 7 days. The actigraph is similar in size to a watch and is used to record their activity and rest patterns, and the light meter measures the amount of light they are exposed to during the day. After the completion of this week, subject will have a light treatment installed in their home that will be in place for 10 weeks. During the last week of the light treatment, subject will again come into Mount Sinai and repeat the questionnaires, memory tests and MRI, and wear the actigraph and light meter. After a 4-week break, subject will again come into Mount Sinai for a third study visit and complete the same questionnaires, memory tests, and MRI, and wear the actigraph and light meter. After this week, subject will have a different type of light treatment installed in their home and left in place for 10 weeks. During the last week of the light treatment, subject will come into Mount Sinai for the final study visit and complete the questionnaires, memory tests and MRI, and wear the actigraph and light meter for 7 days. There are no costs associated with participation, but subject will receive monetary compensation for each of the 4 study visits.
The purpose of this research study is to investigate the effect of a light treatment on sleep, memory and brain function. In people with mild cognitive impairment (MCI) and Alzheimer's disease, sleep-wake disturbance is evident in up to 60% of patients. This can be caused by disruption of circadian rhythms and may affect our health and well-being. Circadian rhythms are the natural cycle of physical, mental, and behavior changes that the body goes through in a 24-hour cycle. Circadian rhythms are mostly affected by light and darkness and are controlled by a small area in the middle of the brain. They can affect sleep, body temperature, hormones, appetite, and other body functions. The circadian system plays an important role in the body and can affect sleep and brain function.~The results of the research would help develop light-delivery methods to improve sleep and memory in patients with mild cognitive impairment (MCI) and Alzheimer's disease who typically spend a significant amount of time indoors.