We're thrilled to announce the results of the world's first, triple-blinded RCT testing a light therapy helmet for Parkinson's disease. These results have been published in the Journal of Clinical Medicine and the Lancet. The Lancet is the world's #1 rated medical journal, making this study a very exciting development for Parkinson's treatment and light therapy (photobiomodulation) medicine.
Study design
The study was conducted at the San in Sydney, Australia, by Director of Research and Neurologist, Dr Geoffrey Herkes (MBBS, PhD, FRACP) and his team. The trial was coordinated remotely, using an infrared and red light therapy helmet that people used in the comfort of their own home. This fully remote design was partly due to covid, which made it difficult for participants to come in for medical appointments, and partly to test the real-life feasibility of the helmet, which was designed specifically for home use.
The study included 40 participants (20 men and 20 women), all diagnosed with idiopathic Parkinson’s disease (PD), with Hoehn and Yahr stages I or II. Trial participants were randomised into two groups of 20 each, with one group receiving the active helmet and the other a placebo (sham) helmet. Both groups treated at home, for 12 weeks.
The active helmet used red light 635 nm for 12 minutes, followed by infrared light 810 nm for 12 minutes, pulsed at 40 Hz (in the same frequency as gamma brainwaves. Gamma brainwaves are the fastest of our 5 natural brainwaves. They are active when we are most alert and focused, and are critical for memory, learning, and concentration (1). Gamma brainwaves have also been shown to be aberrant in people with Parkinson's disease (2)). sham helmet was identical, but had its diodes turned off, so that it didn't emit therapeutic light. Participants were blinded as to whether they received the active or sham treatment. All placebo patients subsequently received active treatment (after the initial 12 weeks plus an additional 4-week washout period).
The MDS-UPDRS part III assessment is one of the most common Parkinson’s assessments used, giving a score to how well someone is moving. It includes testing tremor, walking, balance, stiffness, and other common Parkinson’s motor symptoms that are then calculated to give a total score. The MDS-UPDRS part III was used in this study to rate patient improvements, with a baseline test conducted on each patient before starting treatment, followed by a second test after 12 weeks of treatment. This assessment recorded results across five sub-categories of the PD motor examination: facial expression, walking, tremor, upper limb control and lower limb control.
SAN trial unveils promising results for infrared and red light therapy in Parkinson’s disease.
A 'responder' was someone whose MDS-UPDRS part III motor score decreased by 5 points or more, which indicates a moderate to large clinically important change. 70% of active participants (13/20) and 55% of placebo participants (9/20) were identified as responders at 12 weeks.
While it's evident that there is a strong placebo effect from the sham device, what's even more interesting, however, is that the placebo responders (ie., who received the sham treatment) only significantly improved in one sub-score - lower limb control. This is very different to the active responders (ie., those who received the active treatment), where everyone improved in all 5 sub-scores.
In particular, upper and lower limb control improved the most in the active responder group (an average of 40-58% improvement), however there was also meaningful improvements in tremor (an average of 24% improvement), walking (an average of 28% improvement) and facial expression (an average of 28% improvement).
“There is clearly a placebo effect from using light therapy on some patients, but not on all,” said Dr Herkes.
“Furthermore, one would expect the positive effect of using a sham helmet to diminish over time. We look forward to reporting on more data from this trial in the coming months.”
So, what do these results mean?
These results are very promising, however more research is always needed. More studies are needed using larger numbers of people. It would also be useful to test these results in different Parkinson’s cohorts for example with individuals with higher Hoehn and Yahr scores, and in a study looking exclusively at YOPD, amongst other subgroups.
As Dr Herkes mentioned, we look forward to following these participants over a longer time frame, such as 1 year and longer. The placebo effect is particularly prevalent during the first 12 weeks of an intervention, and there was a strong placebo effect observed in this study. By following participants for a longer time frame, the true effects of a therapy can be determined. This is particularly true for slow-progressing neurodegenerative conditions such as PD, which typically develop over many years. Using laser on the gut is showing that, for people who continue with the treatment, some continue to improve at 1 and 2 year follow-up, while for many others, their initial improvements are maintained at 3 and 5 years follow-up (3-6). The degree of improvement, and of which symptoms, vary considerably from participant to participant.
70% of people using the active light therapy saw a clinically significant result, so what about the other 30%? Not everyone was defined as a 'responder' to light therapy in this trial. 30% of people in the active cohort did not have moderate-large improvements in their motor symptoms. Did they perhaps just need longer with the treatment? Did they still see improvements in their non-motor symptoms, that weren't tested in this study? Were there problems for some people using the helmet at home? Could factors such as covid have got in the way of this study? Or is light therapy not equally as effective for all kinds of people with PD? More research is needed to help determine the answers to these questions.
The future of light therapy for Parkinson's disease
All in all, these results are very promising for the potential of light therapy to help people with Parkinson's. Arguably, when we look at these results from just using a helmet alone, and compare it to treating via the gut, it seems the gut treatment is having a more significant effect for research participants (3-8). This may make sense given the challenges light has to penetrate through the skull, and the important role the gut plays in PD. We also have promising data from the gut treatment at 1, 2, 3 and 5 year follow-up, which we do not yet have for this helmet study (3-6).
You can read more about this study in the following:
1) the Journal of Clinical Medicine
2) the Lancet eClinical Medicine
3) SYMBYX blog on 5 years of continued light therapy use for Parkinson's - trial results now published
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References:
1) Jasek, Roman & Strmiska, Martin & Koudelková, Zuzana. (2018). Analysis of brain waves according to their frequency. International Journal of Biology and Biomedical Engineering. 2018; 12.
2) Guan Ao , Wang Shaoshuang , Huang Ailing , Qiu Chenyue , Li Yansong , Li Xuying , Wang Jinfei , Wang Qiang , Deng Bin. The role of gamma oscillations in central nervous system diseases: Mechanism and treatment. Frontiers in Cellular Neuroscience. 2022; 16.
3) Liebert A, Bicknell B, Laakso EL, Jalilitabaei P, Tilley S, Kiat H, Mitrofanis J. Remote Photobiomodulation Treatment for the Clinical Signs of Parkinson's Disease: A Case Series Conducted During COVID-19. Photobiomodul Photomed Laser Surg. 2022 Feb;40(2):112-122. doi: 10.1089/photob.2021.0056
4) 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
5) Liebert, A., Bicknell, B., Laakso, E., Tilley, S., Pang, V., Heller, G., Mitrofanis, J., Herkes, G., & Kiat, H. (2023). Improvements in the clinical signs of Parkinson’s disease using photobiomodulation: a 3-year follow-up case series. Medical Research Archives, 11(3). doi:10.18103/mra.v11i3.3690
6) https://fightingparkinsons.org.au/news/latest-news/update-on-light-therapy-study/
7) McGee C, Liebert A, Bicknell B, Pang V, Isaac V, McLachlan CS, Kiat H, Herkes G. A Randomized Placebo-Controlled Study of a Transcranial Photobiomodulation Helmet in Parkinson's Disease: Post-Hoc Analysis of Motor Outcomes. J Clin Med. 2023 Apr 13;12(8):2846.
8) Herkes, G.; McGee, C.; Liebert, A.; Bicknell, B.; Isaac, A.; Kiat, H.; McLachlan, C. A novel transcranial photobiomodulation device to address motor signs of Parkinson’s disease: A parallel randomised feasibility study. eClinicalMedicine 2023, 66, 102338.
