Light, Metabolic Syndrome and Alzheimer's Disease - Aim 2

To test the long term effect of a light treatment on cognition, sleep and metabolism in patients with Mild cognitive impairment (MCI) or mild Alzheimer's disease or related dementia (ADRD).

Test if a tailored light intervention (TLI) that promotes entrainment can improve sleep disturbances, inflammation, insulin sensitivity (Si) and glucose disposal (Sg) and cognition in patients with MCI and mild ADRD and sleep disturbances. Using a single-arm, between-subjects, placebo-controlled study the investigators will investigate if long-term (6-month) exposure to TLI improves glucose homeostasis and insulin sensitivity in patients with MCI and mild AD who suffer from sleep disturbance and are living at home. Participants will be recruited from the Mount Sinai AD research center (ADRC) and randomized to receive the TLI (or comparison control treatment) at home. The investigators hypothesize that, compared to the comparison light, a TLI will increase entrainment, improve sleep, reduce depression, reduce inflammation, improve metabolic control, increase insulin sensitivity, and reduce susceptibility to T2DM and metabolic disease during and after the completion of the 6-month intervention.

The TLI will provide high circadian stimulation during the day produced by light sources that provide moderate light levels of spectra that are tuned to the sensitivity of the circadian system. Combining spectrum and light level, TLI will allow us to: (a) use a light source that will stimulate the circadian system, and (b) provide the participants with options as to how the light treatment will be delivered. The investigators will deliver at least 300-400 lux at the eye of the bluish-white light during the day (CS of 0.4 or greater). The lighting intervention will be in place for 24 weeks

The placebo condition light source will be a warm yellow - white (2700 - 3000 K) source providing 50 -100 lux at the eye. The lighting intervention will be in place for 24 weeks.

Change in sleep disturbance will be assessed using the Pittsburgh Sleep Quality Index. The sum of the 7 component scores yields a single global score. A person with a global score above 5 is considered to have sleep disturbances. A higher score indicates worsening sleep disturbance.

Changes in glucose homeostasis and insulin sensitivity will be measured using the Frequently Sampled Intravenous Glucose Tolerance Test (FSIVGTT).

A change in depression will be assessed using the Cornell Scale for Depression in Dementia. A score of nine or more points indicates depression.

Changes in cognition will be assessed by use of the Alzheimer's Disease Assessment Scale- Cognitive Sub scale (ADAS-Cog). All scores are summed and higher scores indicate higher severity of dementia.

Changes in cognition will be assessed using the mini mental state exam (MMSE). All scores are summed for a total score ranging from 0-30. Lower score indicates worsening dementia

Inclusion Criteria: Mild cognitive impairment Mild Alzheimer's Disease Sleep Disturbance Live at home Exclusion Criteria: Blindness insulin-dependent diabetes patients macular degeneration severe sleep apnea