The Bland–Altman analysis for repeated measures on 10-minute

time windows in the awake state (around 7 PM) and during sleep

(around 12 AM) was used to compare OHR and HRECG [6]. The

Mann–Whitney U-test was used to compare the average HRECG and

OHR of all patients in a 10-minute window in both activity states. All

signal preprocessing and statistical analyses were performed with

MATLAB 2011a [7]. The studywas approved by the local research ethics

committee of the Academic Centre for Epileptology Kempenhaeghe.