Evaluation of the Impact of Lesions of the Motor and Proprioceptive Brain and Pan-medullary Pathways on Their Clinically and Electrophysiologically Assessed Function in Multiple Sclerosis

Multiple Sclerosis (MS) is the most common acquired neurological disease leading to disability, especially ambulatory, in young adults. To date, the correlation between the number or volume of white matter lesions seen on conventional MRI and the degree of disability of patients remains low to moderate. This phenomenon is known as the "clinical-radiological paradox". In this new project, we hypothesize that an evaluation of the corticospinal pathways including their thoracic medullary portion, as well as taking into account the severity of the lesions using quantitative MRI, will allow the investigators to refine the correlation with ambulatory disability in MS patients. We will complete the evaluation of motor pathways with those of the proprioceptive pathways also strongly involved in ambulation.