Etiology of fatigue in patients with multiple sclerosis and the role of physical activity

Multiple sclerosis (MS) is a neurodegenerative disease of the central nervous system. Among the manifestations caused by the disease, fatigue is the most common and disabling symptom, being reported by 55% to 78% of MS patients but causes remains poorly understood. This chronic fatigue affects their quality of life by decreasing their capacity to perform simple tasks of daily life due to less resistance to muscle fatigue. In fact, a higher fatigability in MS patients could lead to a greater reduction in functional capacity and over time, the repetition of the activity of daily living could induce fatigue accumulation. However, previous research has focused on single-joint, isometric contractions involving small muscle groups, limiting our understanding of neuromuscular function in relation to dynamic whole-body activity in PwMS. At this day, there are no medications that can reduce or prevent chronic fatigue. However, physical activity has proven to be an effective therapy with benefits on chronic fatigue as well as on different functions (muscular, cardiorespiratory, cognitive, etc.). Our project aims to characterize the causes of chronic fatigue in MS patients using a multifactorial assessment, focusing primarily on neuromuscular function. A better knowledge of chronic fatigue etiology will allow to optimize physical rehabilitation treatments to decrease perceived fatigue and improve life quality.