Fig. 2.

Grip force amplitude and frequency during motor tasks. (A) Analysis of the mean GF amplitude for the more affected, versus the less effected hand in all patients showed a significant correlation, indicating that GF amplitudes did not differ between both extremities within subjects (Slope: 0.92 ± 0.13, R² = 0.82, p < 0.005, N = 12). Across tasks, the mean grip force was higher during Press (magenta, 17.7 ± 7.2 N) than during Shake (blue, 5.8 ± 2.7 N, p < 0.005 paired t-test). (B) The mean movement frequency of Shake and Press was highly correlated across hands (Slope: 0.97 ± 0.19, R² = 0.71, p < 0.005, N = 12, dotted lines: 95% confidence intervals for linear correlation).