Figure 4

Power distribution within tremor and non-tremor windows. The relative power of the angular velocity signals in the low, tremor and high frequency band for the tremor (A) and non-tremor (B) windows of the rest tremor test and for the tremor (C) and non-tremor windows (D) of the action tremor test, respectively. The graphs show the average results for the group of patients; standard deviations are included. All statistically significant differences (p<0.01) between the three frequency bands for each setting as well as the comparison of tremor and non-tremor windows are indicated for each frequency band and each setting (for legibility, the significant differences between the tremor and non-tremor windows for DBS80% and DBSoff are indicated by broken lines). It must be noted that during tremor presence the power concentrated in the high frequency band was partially the result of the higher harmonic(s) of tremor (Figure A and C). However, tremor patterns rather closely resembled sinusoids (see Figure 1A), and therefore harmonic components were small. No significant differences were found for the power in the high frequency band when comparing tremor and non-tremor windows.