EEG and IMU data

60 EEG channels and 4 EOG channels were recorded at a sampling rate of 100 Hzfrom the Brain Products actiCap System.46 The electrodes were placed and labeled using a modified version of the 10-20 system5. Four posterior electrodes – TP9, TP10,47 PO9, PO10 – were reallocated as vertical and horizontal EOG sensors for the recognition and removal of eye movement/blink48 artifacts from the 60 EEG channels using an H∞ filter6. Electrodes FT9 and FT10 were also moved to the standard AFz and49 FCz locations respectively, and the ground and reference electrodes were then placed on the left and right ears. To help maintain50 low impedances, electrolytic gel was injected between each electrode and the subjects’ scalps. Impedances were tested and51 recorded before and after each session. The 3D spatial locations of all 64 electrodes were digitally scanned and recorded for52 most sessions (see Table 1) using the Brain Products CapTrak system; these specific coordinate locations could be used for53 subject- and session-specific EEG source localization and to ensure consistent electrode placement across sessions. Finally,54 an elastic mesh was fitted over the scalp and EEG cap to help keep the electrodes in place and reduce motion artifacts due to55 cable movement during the recording process. In addition to EEG data, each subject was fitted with inertial measurement units56 (Opals, APDM Inc.) in the center of each subject’s foreheads and on the back brace of the exoskeleton. T