Research Article

Dynamic Variability of Isometric Action Tremor in Precision Pinching

Figure 4

Scatter plot of the frequency difference variable against logarithmically scaled total tremor power using values from all trial segments of both the PD and OA groups. At background levels of total power the frequency differences are distributed throughout the theoretical [−2, +2] range, but the variance narrows around a mean near zero as the total tremor power increases beyond background.
975735.fig.004