Research Article

Dynamic Variability of Isometric Action Tremor in Precision Pinching

Figure 2

Example of the evolution of tremor power spectra. The three-dimensional surface plot shows the power spectrum in the 5–7 Hz range for isolated tremor during the force application phase of a trial performed by a PD patient using the more affected hand: (a) tremor from the thumb; (b) tremor from the index finger. Spectra were obtained from a moving four-second window, plotted sequentially with centres at 0.01 second intervals. Note that the peak power in this time region of the task appears oscillatory and the patterns for the thumb and for the index finger are distinguishable.
975735.fig.002a
(a)  Thumb
975735.fig.002b
(b) Index finger