Improvements in the clinical signs of Parkinson’s disease using photobiomodulation: a 3-year follow-up case series

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Ann Liebert, PhD Brian Bicknell, PhD E-Liisa Laakso, PhD Sharon Tilley, PhD Vincent Pang, PhD Gillian Heller, PhD John Mitrofanis, PhD Geoffrey Herkes, PhD Hosen Kiat, MBBS, DMedSc


Parkinson’s disease is a progressive neurodegenerative disease with clinical signs and symptoms that deteriorate over time. We have previously demonstrated that a combination of transcranial and remote photobiomodulation treatment has the potential to improve some clinical signs of Parkinson’s disease for up to one-year. The objective of the current study was to assess the effectiveness of continued home photobiomodulation treatment over a three-year period. Eight of the original twelve participants returned for reassessment at 2 years and six at 3 years. Participants were assessed for mobility, fine motor control, balance, and cognition. Median values for mobility and cognition continued to improve to 2 years and slightly declined to 3-years although not to pre-treatment levels. Individual participants typically improved in some outcome measures to 2-years and some participants continued to improve to 3-years. Cognition was the most sustained outcome improvement and static balance the least. Two participants who discontinued treatment after 1 year showed a decline in outcome measures. No negative side-effects of the treatment were reported. In conclusion, results suggested that at-home photobiomodulation treatment was effective to maintain improvements in clinical signs and symptoms of Parkinson’s disease for as long as treatment continued. The results of this study warrant a larger prospective randomized trial.

Keywords: Parkinson’s disease, photobiomodulation, motor symptoms, cognition, balance

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How to Cite
LIEBERT, Ann et al. Improvements in the clinical signs of Parkinson’s disease using photobiomodulation: a 3-year follow-up case series. Medical Research Archives, [S.l.], v. 11, n. 3, apr. 2023. ISSN 2375-1924. Available at: <>. Date accessed: 20 apr. 2024. doi:
Research Articles


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