Fig. 2

Undulation of center of mass along the line of progression. To evaluate gait symmetry, we examined the undulation of center of mass along the progression line with a temporospatial gait analysis. Preoperatively, the center of mass was located on the non-paretic side of the body, and the position of the center of mass moved to the left and right sides with a great amplitude, with varying degrees of severity, in both patients. In both patients gait symmetry increased after 3 months under stimulation, with less drift to both sides and a shift of the center of mass to the center of the body while walking