A new approach of unconstrained sleep monitoring and pulse arrival time extraction using PPG pillow and CC-ECG electrode system

In this paper, an unconstrained and noninvasive system to detect heart rate (HR), respiratory rate and extract pulse arrival time (PAT) during sleep is proposed. The system consists of PPG sensor module embedded in a pillow and CC-ECG (capacitor coupled-ECG) sensor module. From the PPG sensor, we acquired heart rate and respiratory rate during sleep with simple peak detection algorithm. Besides, by employing extraction algorithms, PAT can be extracted from signal acquired with a CC-ECG electrode placed on a mattress. The result shows that HR and respiratory rate detection and PAT extraction have been successfully completed regardless of sleep position. This study suggests that the proposed system is promising to be used for continuous and unconstrained estimation of blood pressure during sleep.