A historical justification for and retrospective analysis of the systematic application of light therapy in Parkinson’s disease

Abstract

For the past 40 years the primary purpose of therapeutics for Parkinson's disease (PD) has been to replace deficient dopamine (DA) in the nigrostriatal dopamine (NSD) system. Even in the presence of limited efficacy, abundant side effects and impoverished quality of life, the involvement of other systems in the aetiology and treatment of this disorder has been sorely neglected and the excessive use of DA replacement therapy (DART) continues on a global basis. Recent scientific work suggests that the retina plays a major role in NSD function and intimates light therapy in the management of PD. After a thorough review of historical evidence supporting this contention, a retrospective, open-label study on 129 PD patients, whereby they were monitored for a period extending for a few months to eight years, was carried out. Primary motor and non-motor symptoms were monitored using an objectified global rating scale and timed motor tests that were assessed at regular intervals for the duration of the study. Thirty-one patients with other neurological disorders (OND) served as controls to determine whether any therapeutic effects seen with light were generalizable across other conditions. Patients were classified as compliant (COM), semi-compliant (SCOM), or early quit (EQUIT; prematurely discontinued treatment). EQUIT patients showed deterioration, while the COM group improved on most parameters. The SCOM patients were not as good as the COM group. The OND group showed significant improvement in depression and insomnia, but exposure to light did not improve motor function. The total drug burden of PD patients maintained on light was less with fewer side effects than SCOM or EQUIT groups. These results confirm the value of the strategic application of light therapy with controlled doses of DART in PD and warrants further controlled investigation. That the symptomatic improvement continued as long patients remained in the program suggests that exposure to light, under a strict daily regimen, combined with controlled DART, actively slows or arrests the progressive degenerative process underlying PD.

A New Perspective for Parkinson’s Disease: Circadian Rhythm

“…The results revealed that BLT facilitated motor performance recovery of PD patients, and decreased the dosage of dopamine replacement drugs. Meanwhile, improvements in mood and sleep quality were also observed in patients with other neurological disorders [110]. These studies have demonstrated the enabling effect of BLT on motor and non-motor manifestations in PD.…”

Heterogeneity of excessive daytime sleepiness in Parkinson’s disease

“…Показана ее эффективность в лечении инсом-нии и депрессии [131,132]. Исследования фототера-пии у пациентов с БП немногочисленны и прово-дились на небольших группах больных [133][134][135]. В большинстве исследований применение фототе-рапии сопровождалось уменьшением проявлений инсомнии и депрессии при БП.…”

Breaking away from dopamine deficiency: an essential new direction for Parkinson’s disease

“…This work also highlights how conditions such as stress produce constantly fl uctuating states and describe how this is linked to the inhibitory effects of these drugs, thereby eliciting the onset of dyskinesia and ' off ' periods (Shoulson et al , 1975 ;Nutt et al , 1984 ;Durif et al , 1999 ). This is an important factor when considering the possible non-invasive methods that can help to avoid overdosing and provide anxiety reduction (Willis and Turner, 2006;Willis et al, 2012).…”

“…Only when the adverse effects of DART are removed from the equation does the optimal therapeutic potential become more achievable. It has been recently suggested that this may be accomplished by the application of non-invasive methods such as strategic light therapy (Artemenko and Levin , 1996 ;Paus et al , 2007 ;Willis and Turner , 2007 ) in combination with controlled DART dosing (Willis et al , 2012 ).…”