The EEG recordings were performed at the two participating centers and performed using NicoletOne EEG Systems (Natus®), with a sampling rate of either 500 or 1,000 Hz. Nineteen electrodes were positioned according to the International 10–20 system. Most EEGs were recorded with alternating closed eyes, and the eyes were open for 3 min each, but some of the recordings only had closed eyes segments. The participants were alerted if they became visibly drowsy. The neurophysiology assistant recording the EEG made notations in the EEG when the participant closed and opened their eyes. After the recording, the files were exported as raw EEG.
