Efficacy Study of Light Therapy as an Adjunctive Treatment for Parkinson's Disease

Parkinson's disease (PD) is traditionally described as a disorder of compromised dopamine (DA) function in the nigro-striatal dopamine (NSD) system. This system extends from the midbrain, through the hypothalamus and into the forebrain to critical areas involved in the control of motor performance. Restoration of DA content in this system by administering the DA precursor L-dopa or DA agonists reinstates motor control, but provides only symptomatic relief with waning efficacy as the disease advances. Symptoms of depression and sleep disturbances are also commonly seen in PD patients, and the manifestation of these symptoms suggests impaired circadian function.

Although the involvement of the circadian system in PD was intimated in the first formal account of the disorder provided by James Parkinson, it was not until recently that circadian malfunction has been specifically cited as playing a major role in the development and progression of the disease. In addition to scattered reports depicting circadian-like features of PD and related syndromes, a large body of evidence describes the benefits of light therapy in PD from both the preclinical and clinical perspectives.

While the development of a formal understanding has been largely omitted as to the basis for any therapeutic effect exerted by light, recent studies have shown that the nigro-striatal dopamine system is comprised of the same cell type as cells in the retina and the pineal. Such cells are driven by visual input whereby dopamine and melatonin sit in functional opposition to regulate day night activities including sleep, mood, reproduction, anti-oxidation and movement. Hence one may conclude that the circadian system plays a major role in many aspects of PD.

Recent work in PD has also suggested that the efficacy of light therapy is mediated by melatonin and dopamine function in the retina. On this basis it would be reasonable to assume that intervention into the function of the circadian system with light therapy in PD patients might well serve to modify the course and consequences of the disease. The present study serves to extend this finding to the point of providing a practical, non-invasive method for helping patients.

Inclusion criteria

• 1.Males and females, with Stage II - III, idiopathic Parkinson's disease, as assessed by Hoehn-Yahr Scale
• 2. On an optimized, stable dopamine replacement therapy for at least 1 month

Exclusion criteria

• 1. Participants younger than 45 years old
• 2. Participation in a study of investigational or marketed drugs or devices during the 30-day period prior to the prospective subject's Baseline Evaluation or during their involvement in this investigation
• 3. Subjects who are medically complicated, medically unstable and/or have other severe co-morbid disease states, as determined by the Investigator.
• 4. History of psychiatric illness that would preclude compliance with the protocol and/or ability to complete the study safely
• 5. History or current diagnosis of major psychiatric disorder including Bipolar I Disorder that could interfere with accurate assessment and effective treatment
• 6. Have a Beck Depression Inventory-II (BDI-II) score of greater than or equal to 14
• 7. An anticipated need for a change in dopamine replacement therapy during the subject's involvement in the investigation
• 8. Patients on stable anti-depressant dose for less than 6 weeks
• 9. Less than one month since stopping an anti-depressant or psychoactive medication
• 10. History of current or recent (within previous 12 months) alcohol, narcotic or other drug abuse by the Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-5) criteria
• 11. Active suicidal or homicidal ideation or plan as determined by the Investigator or have a score of greater than or equal to 2 on the DBDI-II.
• 12. Previous use of light therapy treatment
• 13. Females of childbearing potential, i.e. capable of becoming pregnant
• 14. Night shift work within the past 6 months or planned during the investigation
• 15. Have planned travel of more than two weeks outside of two time zones from home during involvement in the Investigation
• 16. Planned travel outside of two time zones from home during the last two months of the Subject's involvement in the Investigation
• 17. Current use or use within the previous 1 month of photosensitizing or other medications that in the opinion of the investigator would interfere with the safety of the Subject during the trial including

• amiodarone
• benoxaprofen
• chlorpromazine
• demeclocycline
• fleroxacin
• nalidixic acid
• ofloxacin
• piroxicam
• porfimer
• psoralens
• quinidine
• temoporfin tetracycline
• oral isoretinoin (Accutane)
• St. John's wort
• melatonin
• 18. Have a history of significant eye trauma or disease, retinopathy, and/or cataract of a level that would significantly affect transmission or processing of light through either eye
• 19. Other neurological disorders that in the opinion of the Investigator would interfere with the conduct of the study
• 20. Pre-existing major joint problems that in the opinion of the Investigator would interfere with the conduct of the study
• 21. History of cerebral insult or central nervous system infection that in the opinion of the Investigator would preclude successful participation in Investigation related procedures
• 22. Cognitive impairment, e.g. as determined by the Montreal Cognitive Assessment, that in the opinion of the Investigator would interfere with the conduct of the Investigation
• 23. Focal neurological deficits that in the opinion of the Investigator would interfere with the conduct of the Investigation
• 24. High dopamine replacement therapy (DART) dosage levels or severe dyskinesia attributable to DART that would preclude successful participation in the Investigation related procedures or interventions in the opinion of the site Investigator