If RESTAN4 = "1: Yes", this indicates more than 30 minutes of the sleep period had either lost or unscorable EEG data. RESTAN2 and RESTAN3 indicate when the recording either started or ended in sleep.
I have another question about the online EEG filters. What the online cut-off frequency of EEG recording in the SHHS1 dataset? I just know the sampling frequency is 125HZ.
The high-pass hardware filters for the instrument were 0.15 Hz for EEG channels. There was no ability to set a high filter (low band pass) at acquisition; signal collection began at the mechanical low filter start-up (0.15 or 0.05) and continued to collect without a frequency cut-off.