Effects of Melatonin Supplementation on Muscle Strength, Manual Dexterity, and Postural Balance in Patients Living...

Our previous study revealed the benefits of chronic melatonin intake on dynamic postural imbalance and poor walking capacity induced by multiple sclerosis but its impact on muscle weakness and poor manual dexterity related to this disease has not yet been explored. The objective of the current study was to investigate the effectiveness of 12-week melatonin supplementation on motor skills (i.e., muscle strength, manual dexterity, and static postural balance) and psycho-cognitive status among multiple sclerosis patients. For that, twenty-seven patients were divided into melatonin group (MG, n = 15) and placebo group (PG, n = 12). Melatonin and placebo were each taken at a dose of 3 mg per night, 30 min before bedtime, for 12 weeks. Before and after the intervention, we assessed isokinetic knee muscle strength (dynamometer), manual dexterity (Nine-Hole Peg Test (NHPT)), static postural balance (force platform), mood (Hospital Anxiety and Depression Scale (HADS)), and cognition (Montreal Cognitive Assessment (MoCA), Symbol Digit Modalities Test (SDMT), and Trail Making Test (TMT)). The results showed that the peak torques of knee flexors (120°/s: p = 0.015, Hedges'g (g) = 1.84; 180°/s: p = 0.02, g = 2.06) and extensors (120°/s: p = 0.019, g = 1.63; 180°/s: p = 0.03, g = 2.01) increased in MG comparatively with PG. There was also a decrease in the sway area (bipedal stance) and mediolateral amplitude (unipedal stance) of the center of pressure in MG compared with PG in the eyes-open (both: p < 0.001; g = 4.32, g = 1.99, respectively) and eyes-closed (p = 0.0007, g = 1.31; p = 0.003, g = 1.79, respectively) conditions. The MG showed an increase in MoCA (p = 0.0006, g = 1.51) and SDMT (p = 0.02, g = 0.95) scores, as well as a decrease in HADS-Total score (p = 0.012, g = 1.06), TMT (p = 0.03, g = 0.91) and NHPT durations (p < 0.001, g = 2.36) comparatively with PG. Based on this study, the 12-week melatonin supplementation was effective in improving knee muscle strength, manual dexterity, static postural balance, mood, and cognition in multiple sclerosis patients. For clinical trial regsitration, this study was prospectively recorded in the Pan African Clinical Trial Registry (PACTR202007465309582).