Study Examines Light Therapy for Improving Sleepiness in Parkinson Disease

Treatment with light therapy may improve sleep-wake cycles in patients with Parkinson disease, researchers reported in JAMA Neurology.

Light therapy is often used as a treatment in sleep medicine, but there is limited research into its feasibility specifically for patients with Parkinson disease, who often experience nonmotor manifestations of the disease such as sleepiness. Using a randomized, placebo-controlled, clinical intervention study, researchers examined the safety and efficacy of light therapy on excessive daytime sleepiness linked with Parkinson disease. 

The study, which took place in Parkinson disease centers in Northwestern University and Rush University, included 31 patients (13 male and 18 female). Participants had an Epworth Sleepiness Scale score of 12 or greater and were receiving stable dopaminergic therapy. Participants did not have cognitive impairment or a primary sleep disorder.

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The patients were randomized to either bright light therapy or the control condition of dim-red light therapy. Each therapy session had duration of 1 hour, and patients underwent sessions twice daily for 14 days.

The researchers found that bright light therapy was linked with significant improvements in excessive daytime sleepiness, as measured by the Epworth Sleepiness Scale score.

Several self-reported sleep metrics, including sleep fragmentation, sleep quality, and ease of falling asleep, were also improved with bright light therapy. Actigraphy measurements also indicated that patients showed greater physical activity after light therapy.

Both bright light therapy and dim-red light therapy were linked with better sleep quality, as measured by mean scores on the Pittsburg Sleep Quality Index and the Parkinson’s Disease Sleep Scale.

“Light therapy was well tolerated and may be a feasible intervention for improving sleep-wake cycles in patients with Parkinson disease,” the researchers wrote. However, the investigators stressed that more researched is needed. “Further studies will be required to determine optimal parameters of light therapy for  Parkinson disease.”

—Lauren LeBano

Reference

Videnovic A, Klerman EB, Wang W. Timed light therapy for sleep and daytime sleepiness associated with Parkinson disease. JAMA Neurol. 2017;74(4):411-418.