Fig. 4: DBS-induced entrainment is modulated by movement and is present in patients that had better performance in a motor task.
a Mean power spectrum of 9 STNs during movement corrected to rest period. Values > 1 indicate higher amplitude of entrainment during movement. Shaded area around the spectrum shows the standard error of the mean. b Upper plot: Spectrogram of an exemplary case of STN stimulated at 1.4 mA and 145 Hz. Bottom plot: synchronized movement traces of three blocks of finger tapping lasting 10 s each, with 10 s rest in between. Entrainment persists during the blocks of repetitive finger tapping but fades away directly after the movement is stopped. c Comparisons of the different movement metrics between the group with entrainment (n = 9 STNs) and the group without (n = 4 STNs). LME was used to test for differences between the groups, while taking into account for the repeated measures. It is shown that the group that exhibited entrainment performs better in repetitive finger tapping than the group that did not (mean raise velocity P = 0.017, coefficient of variation of intra-tap interval P = 0.043, normalized RMS P = 0.058, and coefficient of variation of the impact force P = 0.058). DBS amplitude had no significant effect as a fixed effect on these four metrics in Linear Mixed Effects Models. The box length is the interquartile range and the whiskers extend to the minima/maxima of 1.5 x the interquartile range respectively. The lower/upper bound of the box is the 25th/75th percentile respectively. Median is denoted with a horizontal line within the boxplot. Outliers are plotted individually.
