EEG acquisition and preprocessing
BRAIN
The sleep EEG data were collected by a Micromed Brain SPY Plus (Micromed, Italy) at baseline, 6 M, and 24 M after NSCs treatment for all the CP patients. EEG signals were recorded at a 128 Hz sampling rate according to the international 10–20 placement system at the following positions: C3, C4, P3, P4, O1, O2, P7, and P8. The reference electrode was located at Cz, and the ground electrode was located at the central forehead. Electrode impedance was kept below 10 kΩ. Electrocardiogram data were recorded in a separate channel. Ten segments of EEG data in the non-rapid eye movement phase (NREM) II stage of sleep were randomly intercepted by an experienced technician, and each segment lasted 15 s. EEG signal was high pass-filtered at 0.30 Hz and low pass-filtered at 30 Hz.