Simplified stance limb kinetics patterns revealed during gait initiation in early stage of multiple sclerosis.

Background: Although patients with an early stage of Multiple Sclerosis (MS) commonly complain about balance and gait impairments, their troubles remain misunderstood. The objective was to compare body kinematics and lower limb kinetics during gait initiation between patients with MS with an EDSS score ≤ 4 and healthy participants.

Methods: Sixteen patients with MS with a median EDSS score of 2.5 [0-4] and disease duration of 7.4 ± 4.2 years, as well as 16 healthy participants were included, and 3-D motion analysis was performed during gait initiation to calculate spatiotemporal, kinematic and kinetic parameters.

Findings: The center of pressure position at the beginning of the gait initiation was more anterior (p = 0.02) in patients with MS than healthy participants. The kinetic parameters of the stance limb were highly affected in patients with MS compared to healthy participants during gait initiation. The net muscular moments for each joint were significantly different during the anticipatory postural adjustment phase with smoother variations for patients with MS compared to healthy participants.

Interpretation: Early stage MS strongly affects the motor modulation of stance limb kinetics during the anticipatory postural adjustment of gait initiation, without alteration of the execution phase. The net muscular moments are sensitive in detecting unobservable balance impairments and can be used to assess disease progression at the early stage. These results suggest that early rehabilitation programs aimed at improving motor modulation and flexibility in gait initiation should be implemented.