Differences in kinetic factors affecting gait speed between lesion sides in patients with stroke.

The differences in kinetic mechanisms of decreased gait speed across brain lesion sides have not been elucidated, including the arrangement of motor modules reflected by kinetic interjoint coordination. The purpose of this study was to elucidate the differences in the kinetic factors of slow gait speed in patients with stroke on the lesion sides. A three-dimensional motion analysis system was employed to assess joint moment in the lower limb and representative gait parameters in 32 patients with right hemisphere brain damage (RHD) and 38 patients with left hemisphere brain damage (LHD) following stroke as well as 20 healthy controls. Motor module composition and timing were determined using principal component analysis based on the three joint moments in the lower limb in the stance phase, which were the variances accounted for principal components (PCs) and the peak timing in the time series of PCs. A stepwise multiple linear regression analysis was performed to identify the most significant joint moment and PC-associated parameter in explaining gait speed. A negligible difference was observed in age, weight, height, and gait speed among patients with RHD and LHD and controls. The following factors contributed to gait speed: in patients with RHD, larger ankle plantarflexion moment on the paretic ( = 0.001) and nonparetic ( = 0.002) sides and ankle dorsiflexion moment on the nonparetic side ( = 0.004); in patients with LHD, larger ankle plantarflexion moment ( < 0.001) and delayed peak timing of the first PC ( = 0.012) on the paretic side as well as ankle dorsiflexion moment on the nonparetic side ( < 0.001); in the controls, delayed peak timing of the first PC ( = 0.002) on the right side and larger ankle dorsiflexion moment ( = 0.001) as well as larger hip flexion moment on the left side ( = 0.023). The findings suggest that the kinetic mechanisms of gait speed may differ among patients with RHD following patients with stroke with LHD, and controls.