Bright Light Therapy for Non-motor Symptoms in Parkinson's Disease

Bright Light Modulation of Non-motor Symptoms in Parkinson's Disease

Disruption of sleep and alertness is one of the most disabling non-motor symptoms of Parkinson's disease (PD). Mechanisms leading to impaired sleep and alertness in PD are not well understood, and treatment options remain limited. The proposed research will examine markers of the circadian system, sleepiness and sleep quality in PD patients. Further, the project will examine effects of bright light exposure on circadin function, sleep and alertness in PD.

Inclusion criteria:

1. Diagnosis of idiopathic PD as defined by the United Kingdom PD Society Brain Bank Criteria
2. PD Hoehn and Yahr stage 2-4
3. Pittsburgh Sleep Quality Index (PSQI) score ≥ 5
4. Treatment with levodopa and/or dopamine agonist; adjunctive PD medications will be allowed
5. Stable dose of PD medications for at least 4 weeks prior to the study screening.

Exclusion criteria:

1. Atypical or secondary forms of parkinsonism
2. Co-existent significant sleep apnea (as assessed by polysomnography- derived apnea/hypopnea index ≥15 events/hr of sleep)
3. Co-existent restless legs syndrome (RLS), as assessed by the International Classification of Sleep Disorders (ICDS) diagnostic criteria for RLS
4. Cognitive impairment as determined by the Mini-Mental State Examination (MMSE) score of ≤ 26
5. Presence of depression defined as the Beck Depression Inventory (BDI) score >14
6. Untreated hallucinations or psychosis (drug-induced or spontaneous)
7. Use of hypno-sedative drugs for sleep or stimulants; participants will be allowed to taper these drugs and will become eligible 4 weeks after the taper is completed
8. Use of Selective Serotonin Reuptake Inhibitors (SSRIs) / Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs) antidepressants, unless the participant has been on a stable dose for at least 3 months prior to the screening
9. Use of medications known to affect melatonin secretion, such as lithium, alpha- and beta-adrenergic antagonists
10. Shift work, currently or within the prior 3 months
11. Travel through ≥ 2 time zones within 60 days prior to study screening
12. Hematocrit <32 mm3
13. Pre-existing glaucoma/retinal disease contraindicated for light therapy (LT)
14. Dense cataracts
15. Use of medications known to photosensitize retinal tissue (phenothiazines, chloroquine, amiodarone, St. John's Wort)
16. Unstable/serious medical illness.
17. Pregnancy