[Note: for more on the action of bright light therapy see “Using Bright Light Therapy to Avoid Seasonal Affective Disorder.”]
Several observations suggest a beneficial effect of melatonin antagonism for Parkinson's disease (PD). Although bright light therapy (BLT) suppresses melatonin release and is an established treatment for depression and sleep disturbances, it has not been evaluated in PD. [Melatonin levels drive the sleep/wake cycle; suppression (antagonism) is linked to waking.]
We examined effects of BLT on motor symptoms, depression, and sleep in PD in a randomized placebo-controlled double-blind study in 36 PD patients, using Parkinson's Disease Rating Scale (UPDRS) I-IV, Beck's Depression Inventory, and Epworth Sleepiness Scale.
All patients received bright light therapy for 15 days in the morning, 30 min daily. Illuminance was 7.500 lux in the active treatment group and 950 lux in the placebo group.
Although group differences were small, bright light therapy led to significant improvement of tremor, UPDRS I, II, and IV, and depression in the active treatment group but not in the placebo group.
It was very well tolerated.
Follow up studies in more advanced patient populations employing longer treatment durations are warranted.
Source: Movement Disorders, Jul 30, 2007;22(10:1495-98. PMID: 17516492, by Paus S, Schmitz-Hubsch T, Wullner U, Vogel A, Klockgether T, Abele M. Department of Neurology, University of Bonn, Bonn, Germany. [E-mail: firstname.lastname@example.org]