IntroductionRespiratory dysfunction is one of the main causes of morbidity during the course of multiple sclerosis. We distinguish four main causes for respiratory dysfunction: respiratory muscles weakness, deglutition disorders, sleep disordered breathing, and control of breathing abnormalities [1].ObjectiveThe main purpose of this study was to describe the respiratory function of MS patients with motor disability.Materials and methodsWe conducted a prospective study in MS patients with a walking disability. The respiratory dysfunction was assessed with pulmonary function tests, using spirometric and plethysmographic measures. The motor respiratory dysfunction was assessed using the vital capacity (VC), in the sitting and upright positions. Maximum inspiratory and expiratory pressures were also measured. We also reviewed the history of associated deglutition and sleep disorders.ResultsOver a 2-year period, 81 patients were evaluated. The median EDSS was 8 (IQ 7–8.5), the mean duration of disease was 20 years±11.4 and mean time since loss of walking ability 6.9 years±5.3. The average vital capacity was 2.41 L±1.08, i.e. 70,7±0.3% of theoretical value. Fifty-one patients (63%) had a significative decrease of VC (