FIG. 5.

Acute effects of submotor threshold spinal stimulation on the limits of stability (LoS) during the “octagon” multi-directional leaning test. (A) Density plot of the center of pressure (COP) excursions during the “octagon” test for a representative participant (P2) without (left) and with (right) spinal stimulation. The distribution of directional displacement events, occurrence of a magnitude of displacement binned into uniform time windows, is shown in both the mediolateral (M-L) direction above each density plot and in the anteroposterior (A-P) direction to the right of each density plot. Note the distribution of the bins; the presence of spinal stimulation results in a more normal distribution of movement. (B) The M-L and A-P time series, with positive values representing the directions right and forward, and negative values representing the directions left and backward. The pooled percent increases in the LoS in the presence of spinal stimulation compared with no stimulation for all participants (n = 8) are shown to the right of each time series plot. Note the significant increase in all leaning directions. *statistical significance; two tailed nonparametric Wilcoxon signed-rank test in which n = 8 and α < 0.05.