Parkinson’s disease (PD) is a debilitating neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta, located in the midbrain section, which controls movement. This leads to motor and non-motor symptoms.

Brain photobiomodulation (PBM) has emerged as a promising non-invasive approach for neuroprotection in PD. This article reviews the underlying mechanisms of PBM and its potential application in PD therapy, based on preclinical and clinical evidence.

Introduction

Parkinson’s disease (PD) is the second most common neurodegenerative disorder, the first being Alzheimer’s disease. While the direct causes of PD remains unknown, mitochondrial dysfunction, oxidative stress, and neuroinflammation are thought to contribute to the progressive loss of dopaminergic neurons in the substantia nigra. Current treatments provide symptomatic relief but do not halt disease progression.

Brain photobiomodulation (PBM) offers a novel therapeutic strategy by harnessing the well-researchedneuroprotective properties of NIR light energy to mitigate pathological processes implicated in PD.

Mechanisms of Brain Photobiomodulation

brain photobiomodulation benefits vs Parkinsons

Mechanisms of brain photobiomodulation

PBM involves the application of low-level light, typically in the red to near-infrared spectrum, to stimulate cellular function. Light energy is absorbed by mitochondria, leading to increased adenosine triphosphate (ATP) production and upregulation of cellular metabolism. PBM also modulates oxidative stress by enhancing antioxidant defenses and reducing reactive oxygen species (ROS) production. Furthermore, PBM exerts anti-inflammatory effects by inhibiting pro-inflammatory cytokines and promoting microglial polarization towards an anti-inflammatory phenotype. These mechanisms collectively contribute to neuroprotection and neuroplasticity, making PBM a promising therapeutic approach for neurodegenerative diseases like PD.

Preclinical Evidence

Animal models of PD treated with PBM have shown improvements in motor function and preservation of dopaminergic neurons in the substantia nigra. Studies have demonstrated reduced neuroinflammation, oxidative stress, and alpha-synuclein aggregation following PBM treatment. Moreover, PBM enhances neurogenesis and synaptic plasticity, suggesting its potential to restore neuronal circuitry in PD.

Clinical Evidence

Initial clinical trials have demonstrated the safety and efficacy of PBM in PD patients. Transcranial PBM has been shown to improve motor function, reduce rigidity, and enhance quality of life in individuals with PD. Neuroimaging studies have revealed changes in cerebral blood flow and neural activity following PBM treatment, indicating its modulatory effects on brain function.

While larger-scale trials are needed to validate these findings, PBM holds promise as a complementary therapy for PD management.

Parkinsons Study with the Vielight Neuro Gamma

The Vielight Neuro Gamma

In a Parkinson’s study by Dr. Ann Liebert et al, from the University of Sydney, the Vielight Neuro Gamma was utilized for transcranial-intranasal brain photobiomodulation and produced statistically significant clinical results.

Methods: Twelve participants diagnosed with idiopathic Parkinson’s disease (PD) were enlisted for the study. Random selection was employed, with six participants assigned to undergo 12 weeks of transcranial, intranasal, neck, and abdominal photobiomodulation (PBM) treatment. The remaining six participants were placed on a waitlist for 14 weeks before initiating the same treatment. Following the 12-week treatment period, all participants were provided with PBM devices for continued home treatment. Assessments of mobility, fine motor skills, balance, and cognition were conducted at baseline, after 4 weeks of treatment, after 12 weeks of treatment, and at the conclusion of the home treatment period. Treatment effectiveness was evaluated using the Wilcoxon Signed Ranks test with a significance level set at 5%.

Results: Significant improvements (p < 0.05) in measures of mobility, cognition, dynamic balance, and fine motor skills were observed with 12 weeks of PBM treatment, persisting for up to one year. Many individual improvements exceeded the threshold deemed clinically meaningful for participants, with variations in the extent of improvement. Notably, improvements were sustained for up to one year with continued home treatment, indicating a sustained treatment effect. A minor Hawthorne Effect was observed, which was below the treatment effect, and no adverse side effects of the treatment were noted.

Figure 3 – Heatmap of Parkinsons Photobiomodulation Clinical Results – University of Sydney

PBM emerged as a safe and potentially effective intervention for addressing various clinical manifestations of PD. The observed improvements were sustained as long as the treatment was continued, even in a neurodegenerative condition where deterioration is typically expected. Home-based PD treatment, either self-administered or assisted by a caregiver, may present a viable therapeutic option. These findings underscore the necessity for a large-scale randomized controlled trial (RCT) to further validate the efficacy of PBM in PD management.

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Challenges and Future Directions

Despite the encouraging results, several challenges need to be addressed for the widespread adoption of PBM in PD therapy. Standardization of treatment protocols, optimization of light parameters, and identification of patient-specific factors influencing treatment response are essential. Long-term studies are warranted to assess the durability of PBM effects and its potential as a disease-modifying therapy in PD.

Conclusion

Brain photobiomodulation represents a novel and promising approach for neuroprotection in Parkinson’s disease. By targeting underlying pathological processes such as mitochondrial dysfunction, oxidative stress, and neuroinflammation, PBM has the potential to slow disease progression and improve quality of life for PD patients. Continued research efforts are needed to fully elucidate the mechanisms of PBM and optimize its therapeutic application in PD management.

References

1. Hamblin, M. R. (2016). Shining light on the head: Photobiomodulation for brain disorders. BBA Clinical, 6, 113-124.
2. Moro, C., Torres, N., El Massri, N., Ratel, D., Johnstone, D. M., Stone, J., & Benabid, A. L. (2014). Photobiomodulation preserves behaviour and midbrain dopaminergic cells from MPTP toxicity: Evidence from two mouse strains. BMC Neuroscience, 15(1), 89.
3. Salehpour, F., Mahmoudi, J., Kamari, F., Sadigh-Eteghad, S., Rasta, S. H., & Hamblin, M. R. (2018). Brain Photobiomodulation Therapy: a Narrative Review. Molecular Neurobiology, 55(8), 6601-6636.
4. Unal, O., & Tuncer, S. (2019). The effect of transcranial photobiomodulation on balance and gait in patients with Parkinson’s disease: a randomized controlled trial. Photomedicine and Laser Surgery, 37(5), 271-277.
5. Liebert A, Bicknell B, Laakso EL, Heller G, Jalilitabaei P, Tilley S, Mitrofanis J, Kiat H. Improvements in clinical signs of Parkinson’s disease using photobiomodulation: a prospective proof-of-concept study. BMC Neurol. 2021 Jul 2;21(1):256. doi: 10.1186/s12883-021-02248-y. PMID: 34215216; PMCID: PMC8249215.