Fig. 2: Walking performance development.

A shows an example of the variations in gait kinematics in response to different DBS settings. B displays the corresponding fluctuations in the Walking Performance Index (WPI). The column with the hatched pattern represents the clinically optimized DBS settings tested at each visit. Heatmap in (C) shows the pairwise Pearson correlation coefficients among all gait metrics and the WPI. The matrix visualizes the degree of linear relationships between variables, with color intensity representing the strength of the correlations: colors range from green (lower values) to yellow (higher values). The low off-diagonal values (green shades) indicate minimal multicollinearity among the metrics, confirming that each metric provides unique and independent information contributing to the WPI. D and E show the correlation between the WPI rankings and feedback received from the subject (D), and evaluations from the physical therapist (E). Green, blue, and red dots represent data from subjects 1, 2, and 3, respectively. The x-axis displays the rankings based on WPI scores, while the y-axis shows the rankings provided by the patients. In both axes, lower numbers indicate higher rankings, with a rank of 1 representing the best performance or preference.