Overall, 16 patients were included in this study and were implanted with the ECoG and DBS electrodes (see Fig. 1A, and B for exemplar electrode locations of Patient Sub5). Table 1 summarizes the demographics, outcomes of motor assessments, and stimulation parameters used during lead externalization. The 16 subjects were on average 66.1 years old, with an average disease duration of 9.3 years. The average preoperative MDS-UPDRS III scored 50.1 in the OFF-medication state, which was reduced to 25.1 in the on-stimulation/OFF-medication state, rendering an average motor improvement of 49.9%. Two subjects were excluded from later analyses: Patient Sub7 was unable to complete the required number of walking trials due to severe gait problems, and Patient Sub10’s subdural electrode was shifted, not covering M1. Thus, the electrophysiology and motion data from the remaining 14 subjects were analysed. A total of 451 walking trials at a self-selected pace were completed by the 14 patients (Fig. 1C). After independent subjective and objective inspections, consensus between the two approaches was reached in 407 trials on whether the trial contained freezing (inter-rater reliability = 90.2%).
