Transcranial photobiomodulation for the treatment of Parkinson’s disease

Introduction: Parkinson's disease (PD) is a progressive neurodegenerative disease largely attributed to dysfunction of the basal ganglia, a set of deep-brain nuclei critical for movement regulation via dopamine. Such dysregulation contributes to the motor and non-motor symptoms of PD, including slowness of movement, rest tremor, rigidity, postural instability, and cognitive decline. While current pharmacologic treatments can help ease symptoms, their effectiveness often declines as the disease progresses. Surgical treatment options such as deep brain stimulation have proven to be effective but are invasive and often not suitable for everyone, highlighting the need for alternative or complementary interventions. This project explores the potential of transcranial photobiomodulation (tPBM), a non-invasive brain stimulation technique that sends low-level infrared light to cortical brain regions, and has been shown to increase cerebral blood flow and cellular metabolism (Bicknell et al., 2024; Gaggi & Iosifescu, 2025). Given the frontal cortex’s role in executive function and its connection to the basal ganglia, we investigated whether tPBM delivered to the frontal cortex can improve motor and cognitive symptoms in PD.Methods: tPBM was delivered 3 times a week for six weeks (810 nm wavelength, 12 min per session) with pre-post assessments of cognitive and motor function performed in the off-medication state (~12 h washout). Outcome measures included validated tools, such as the motor section of the MDS-Unified Parkinson's Disease Rating Scale (MDS-UPDRS-III) and the KinesiaOne wearable motion sensor. To date, 26 participants (age: 68.25 ± 7.95, gender: 8F, 18M) have completed the intervention, with 16 receiving active treatment and 10 receiving sham treatment. Paired T-tests were used to assess pre-post results.Results: Preliminary results suggest that the active treatment group showed greater improvements (lower scores) compared to the sham for both measures. Total MDS-UPDRS-III scores for the active group showed reductions of approximately 4 points when compared to the sham. For KinesiaOne, the average total and upper extremity scores improved by 4 points for the active group and only by 1 point for the sham.Conclusions: The intervention remains ongoing to solidify these preliminary findings. If proven effective, tPBM could serve as a powerful adjunct tool for the treatment of PD, with the potential to alleviate symptoms and enhance quality of life.Acknowledgements: Luis DeTaboada and Bryan Pryor hold US Patent 7,303,57: Device and Method for Providing Phototherapy to the Brain (NeuroThera, Inc).