For data recorded during rest sitting and standing, the first continuous 30 s data without artifact and movement were selected for analysis. For data recorded during walking, the whole length of data recorded in completing the walking trial was analysed. PAC was calculated using a 10 s sliding window with a 5 s step size and averaged among windows. A 10 s sliding window was selected because the shortest walking trial lasted 11 s. Ten seconds is a reliable calculation length, which contains over 130 cycles of beta-band phase.27Supplementary Fig. 1A and B show that the 10 s-window MIs were highly linearly correlated with the 30 s-window MIs in both the trial wise correlation (Spearman r = 0.88, P < 0.001) and the subject wise correlation (Spearman r = 0.97, P < 0.001). PAC statistics were then compared among the standing, freezing, and non-freezing trials.
