Acute Effects Of Photobiomodulation Therapy On Muscle Force Recovery In Persons With Multiple Sclerosis: 337 Board #153 May 27 10:30 AM - 12:00 PM

Symptomatic fatigue, as well as muscle fatigue, are common in persons with multiple sclerosis (PwMS), and both can negatively affect quality of life (QOL). Photobiomodulation Therapy (PBMT), comprising light in a 600-1000 nm bandwidth, is an emerging therapeutic modality thought to enhance mitochondrial function. There is evidence that PBMT can improve muscle fatigue, inflammation, and psychological status and thus might be beneficial for PwMS. PURPOSE: To investigate PBMT on muscle force recovery after a fatiguing contraction in PwMS. A secondary aim was to determine if self-reported symptom outcomes influenced the response to PBMT. METHODS: Randomized double-blinded repeated-measures design. Ambulatory males and females (n=17, 14 females) with relapsing-remitting MS were evaluated pre- and post-PBMT in 4 visits over 4 weeks. The muscle function measurements consisted of 3 maximal voluntary contractions (MVCs) of Tibialis Anterior (TA) muscle followed by 2 min. of intermittent isometric contraction at 45% MVC. PBMT was then administered to the TA muscle belly at 1 of 4 energies: 40J, 80J, 120J or placebo (active device: 3 pulsed wavelengths at the same time including 640nm, 875nm, and 905nm, placebo device: single pulsed wavelength at 640 nm). After PBMT, recovery MVC’s were obtained. Baseline psychosocial measurements comprising depression (CES-D), fatigue (MFIS) and QOL (PROMIS) were obtained during visit 1. McNemar’s test was used to test for each light dose compared to placebo and Spearman’s correlations were compared with Fisher’s r to z transformation. RESULTS: All subjects were able to recover strength to within 12% of their initial strength during the 120J visit. However, 6/17 subjects did not recover to the same degree after the placebo. This difference in force recovery between high (120J) dose and placebo was significant with p=0.03. Muscle recovery correlations with depression and QOL differed between 120J vs. Placebo (0.35 vs. -0.44, p=0.03 and -0.09 vs. 0.67, p=0.03, respectively). CONCLUSIONS: PBMT at 120J may improve muscle force recovery in PwMS. Those reporting greater depression, or lower QOL may benefit most from PBMT. Supported by a pilot grant from the National MS Society