Impaired speed-dependent modulation of the gait pattern in multiple sclerosis.

BACKGROUND: Walking dysfunction is common in people with multiple sclerosis (MS). Besides walking speed or endurance, one crucial feature of ambulatory function is the ability to adjust the gait pattern according to walking speed which relies on the integrity of spinal motor centres, their reciprocal connections to supraspinal networks and peripheral sensory input. OBJECTIVE: To investigate the capacity of people with MS to modify their gait pattern in response to changes in walking speed. METHODS: 3D gait analysis during free treadmill walking was performed in 35 people with MS and 20 healthy controls. Twelve kinematic parameters ranging from basic spatiotemporal measures to complex indicators of intralimb coordination were assessed at different absolute and relative walking speeds. RESULTS: Cadence, double-limb support time, trunk movements and especially measures of intralimb coordination demonstrated significantly less speed-dependent modifications in MS than in controls. These limitations were more prominent in subjects with stronger MS-related impairment (worse outcome in clinical walking tests, higher Expanded Disability Status Scale). CONCLUSION: The incapacity to modify specific elements of the walking pattern according to walking speed contributes to gait dysfunction in people with MS limiting activities of daily living. Gait modulation may serve as sensitive marker of walking function in MS. TRIAL REGISTRATION: Clinicaltrials.gov, NCT01576354; first posted April 12, 2012.