ECG Recording on a Bed During Sleep Without Direct Skin-Contact

TLDR

The study introduces an indirect contact ECG (IDC‑ECG) system designed for long‑term sleep monitoring without direct skin contact. IDC‑ECG employs high‑input‑impedance active electrodes mounted on the mattress and a conductive textile ground, all covered by a thin cotton bedcover, allowing signal acquisition without direct skin contact. The system successfully recorded ECG signals with adequate R‑peak detection for HRV analysis, though signal quality and motion artifacts were higher than conventional direct‑contact ECG, indicating the need for further research before clinical diagnosis.

Abstract

A new indirect contact (IDC) electrocardiogram (ECG) measurement method (IDC-ECG) for monitoring ECG during sleep that is adequate for long-term use is provided. The provided method did not require any direct conductive contact between the instrument and bare skin. This method utilizes an array of high-input-impedance active electrodes fixed on the mattress and an indirect-skin-contact ground made of a large conductive textile sheet. A thin cotton bedcover covered the mattress, electrodes, and conductive textile, and the participants were positioned on the mattress over the bedcover. An ECG was successfully obtained, although the signal quality was lower and the motion artifact was larger than in conventional direct-contact measurements (DC-ECG). The results showed that further studies are required to apply the provided method to an ECG diagnosis of cardiovascular diseases. However, currently the method can be used for HRV assessment with easy discrimination of R-peaks.