Fig. 4:

Symmetry scores for the stiffness measure. Symmetry scores were determined by subtracting the quantitative rigidity measure of the less affected limb from the more affected limb, thus values closest to zero indicate the greatest symmetry. Symmetry scores were significantly higher in the Parkinson’s disease without RSWA (PD-RSWA−) group compared to the control group (Tukey’s Honestly Significant Difference test, * p = 0.031) in the no activation maneuver condition. In the condition with an activation maneuver, the PD-RSWA− group had significantly higher symmetry scores than both the Parkinson’s disease with RSWA (PD-RSWA+) and control groups (Tukey’s Honestly Significant Difference test, * p < 0.018). Boxes range from the first to the third quartile, whiskers extend to 90% confidence intervals, median is indicated by a line across the box, and mean is indicated by a square marker. Individual data points are indicated with diamonds.

RSWA: REM sleep without atonia.