Transcranial Photobiomodulation: a Feasibility and Safety Study with Implications for Signs and Symptoms of Parkinson's Disease
Creators: name: McGee, Claire
Publisher: name: Torrens University Australia
Year: 2024
Subjects: classificationCode: 320905
subject: Neurology and neuromuscular diseases

description: <b>Title: </b>Safety and Feasibility of Transcranial Photobiomodulation on Signs and Symptoms of Parkinson's Disease.<b>Objective: </b>This quasi double-blinded randomized controlled trial aimed to investigate the safety and feasibility of using transcranial Photobiomodulation (tPBM) to reduce signs and symptoms in patients with Parkinson’s disease.<b>Methods: </b>Forty participants diagnosed with early-stage PD were randomly assigned to either a tPBM group or sham group. The tPBM group received home treatment of transcranial near-infrared light therapy for 24 mins, 6 times per week for 12 weeks. The placebo group underwent a sham treatment with a helmet that did not produce light. Stage 1 of the RCT concluded following 12 weeks. Participants who initially received the sham intervention had the option to continue into stage 2 unblinded for an additional 12 weeks with active treatment.The primary motor outcome measure in Stage 1 was the Movement Disorder Society-Unified Parkinson's Disease Rating Scale, Part III motor score (MDS-UPDRS-III) modified for remote delivery, assessed at baseline and 12 weeks. Safety was also continuously monitored. Other outcome measures included the Timed-up and go (TUG), Montreal cognitive assessment (MoCA) and the self-reported symptom scales Parkinson’s disease sleep scale (PDSS) and 39-item Parkinson's Disease Questionnaire PDQ-39. Treatment was delivered remotely, and all assessments were obtained via video conference link due to the SARS-CoV-2 pandemic.<b>Results: </b>The treatment raised no serious safety concerns or adverse events. Two sham participants experienced sporadic, transient, and minor episodes of dizziness. No participants withdrew from the trial due to adverse reactions to treatment. In stage 1 all participants in the active group and 18 in the sham group completed full treatment, with the two withdrawals due to unrelated medical conditions. The mean change in the modified MDS-UPDRS-III score between baseline and after 12 weeks of treatment was 5.59 (SD 7.9) for the active group and 4.85 (SD 7.6) for the sham group. These results in both groups denoted a significant improvement in the MDS-UPDRS-III scores, however, no significant difference was noted between the groups. The improvement in both groups most likely reflects the highly reported dopamine placebo response that typically occurs in PD patients. All other assessments revealed no significant positive changes between the sham and tPBM groups. However, individual participants demonstrated improvements in several signs and symptoms. As heterogeneity in PD is marked, with a substantial variability in clinical presentation, progression, and response to treatment, identifying which patient characteristics lead to a favourable response may aid in generating additional hypotheses and providing insights into the individualised effects of the treatment.<b>Conclusion: </b>tPBM appears to be safe and a promising adjunctive therapy for managing signs and symptoms in PD. However, the heterogeneity of PD may underscore the diversity of patient responses to treatment and complicate the assessment of treatment efficacy. The placebo affect reported here suggests the need for a longer trial where this response may be blunted. As well, as an individual response to treatment noted in this study, the possibility of identifying "responders" within specific disease subtypes and tailoring treatments to address this variation would be worth investigating. This approach can lead to more effective and targeted therapies, improving patient outcomes in the face of this complex and variable disease presentation.Further research is warranted to explore whether stratifying patients into subgroups, considering factors like genetic mutations, biomarkers, or clinical characteristics when providing treatment may reveal a specific group of responders. Overall, further research with larger sample sizes and protracted treatment may provide a better understanding of the long-term effects on specific signs and symptoms that tPBM may provide.