Improvements in clinical signs of Parkinson’s disease using photobiomodulation: a prospective proof of concept study


Background: Parkinson’s disease (PD) is a progressive neurodegenerative disease with no cure and few treatment
options. Its incidence is increasing due to aging populations, longer disease duration and potentially as a COVID-19
sequela. Photobiomodulation (PBM) has been successfully used in animal models to reduce the signs of PD and to
protect dopaminergic neurons.
Objective: To assess the effectiveness of PBM to mitigate clinical signs of PD in a prospective proof-of-concept
study, using a combination of transcranial and remote treatment, in order to inform on best practice for a larger
randomized placebo-controlled trial (RCT).
Methods: Twelve participants with idiopathic PD were recruited. Six were randomly chosen to begin 12 weeks of
transcranial, intranasal, neck and abdominal PBM. The remaining 6 were waitlisted for 14 weeks before commencing
the same treatment. After the 12-week treatment period, all participants were supplied with PBM devices to
continue home treatment. Participants were assessed for mobility, fine motor skills, balance and cognition before
treatment began, after 4 weeks of treatment, after 12 weeks of treatment and the end of the home treatment
period. A Wilcoxon Signed Ranks test was used to assess treatment effectiveness at a significance level of 5%.
Results: Measures of mobility, cognition, dynamic balance and fine motor skill were significantly improved (p <
0.05) with PBM treatment for 12 weeks and up to one year. Many individual improvements were above the minimal
clinically important difference, the threshold judged to be meaningful for participants. Individual improvements
varied but many continued for up to one year with sustained home treatment. There was a demonstrable
Hawthorne Effect that was below the treatment effect. No side effects of the treatment were observed.

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