Fatigue & Multiple sclerosis Thesis by Nicolas Royer

Supervisors: Pr Guillaume MILLET & Pr Jean-Philippe CAMDESSANCHÉ

Multiple sclerosis (MS) is a neurodegenerative disease targeting myelin of the central nervous system. More than 2 500 000 people in world and 100 000 in France were affect by this neurological disorder. Among the manifestations caused by the disease, fatigue is the most common and disabling symptom, being reported by 80% of MS patients.

Recently, a higher neuromuscular fatigue in MS patients was measured after a cycling task. This higher fatigability could lead to a greater reduction in functional capacity and over time, the repetition of the activity of daily living could induce fatigue accumulation and affects their quality of life. 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.

The first part of this project aims to characterize the causes of chronic fatigue in MS patients using a multifactorial assessment, focusing primarily on neuromuscular function during cycling exercise, i.e. i.e. a dynamic exercise involving large muscle masses. A better knowledge of theses causes will allow to develop a personalized physical rehabilitation to decrease chronic fatigue and improve quality of life.

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.). However, the effects of exercise may be different between PwMS, as MS is a heterogeneous disease and the causes of fatigue are varied (reduced muscle strength, deteriorated cardio respiratory capacity, sleep disorders etc.). From this observation, a tailored intervention seems appropriate and very promising.

The second part of this project aims to compare the benefits of a tailored training program adapted to deficits measured (muscular dysfunction, cardiorespiratory fitness, inflammation, sleep disorders...) to those induced by a conventional training program following the guidelines in patients with multiple sclerosis, in order to reduce their feeling of fatigue and improve their quality of life.

The whole project will be conducted within the Interuniversity Laboratory of Motor Biology (LIBM) in collaboration with the neurology department of the University Hospital of Saint-Etienne.