To assess the effects of a short-term tailored lighting intervention therapy (TLI) on sleep disturbances in Parkinson disease (PD).

Sleep disturbances are a common non-motor symptom in PD, adversely affecting quality of life, mood and cognition. They suggest underlying disruptions in circadian rhythm. Based on our preliminary studies showing the positive impacts of TLI on sleep, mood and behavior in Alzheimer’s disease, we hypothesize that TLI can improve objective sleep measures in PD.

Baseline sleep quality and rest activity were measured with 1-week wrist actigraphy. Light exposure level was measured with a daysimeter. TLI was delivered over a 4-week period, administered for 2 hours every morning via table/floor lamps installed in the home or lighting glasses. Post-intervention actigraph and daysimeter data were collected during the last week of the 4-week intervention. Pre- and post-intervention measures were compared using paired t-tests.

In 20 participants (65% women, mean age 73.8 years [SD 8.6], disease duration 9.4 years [7.4]), average time of falling asleep was 19 minutes earlier (p=0.18) with TLI. Sleep time (excluding nocturnal wake after sleep onset) increased significantly by 20 minutes (p=0.049) from 381.11 to 401.36 minutes. Overall sleep duration also increased by 29 minutes but this did not reach significance (p=0.078). Sleep efficiency in this PD cohort was 85% both pre- and post- intervention.

This pilot study demonstrates the feasibility of conducting an at home, short-term tailored lighting intervention therapy for participants with PD. In this small group, several sleep measures were improved, despite starting with an overall baseline of good sleep efficiency. Additional analyses are underway to determine effects of TLI on subjective sleep quality, daytime sleepiness, depression, anxiety and fatigue. Follow up studies in a larger cohort are warranted to assess for effects of TLI in participants with poor baseline sleep, as well as longer intervention durations.