Signal Quality and Reliability of Heart Rate Measurement Using Simultaneous PPG and Inertial Data in Healthy Adults.

Area of Science:

• Biomedical Engineering
• Cardiovascular Physiology
• Mobile Health Technology

Background:

• Accurate heart rate and beat-to-beat interval estimation is crucial for cardiovascular health monitoring.
• Smartphone sensors like photoplethysmography (PPG) and inertial measurement units (IMUs) provide accessible data but are sensitive to how they are used.
• Understanding how different usage scenarios affect sensor reliability is key for clinical application.

Purpose of the Study:

• To investigate the impact of different smartphone acquisition configurations on the agreement of RR intervals derived from PPG and accelerometer data.
• To compare the reliability of RR interval measurements using single-device versus synchronized dual-device smartphone setups.

Main Methods:

• An observational pilot study recorded simultaneous PPG and accelerometer signals from smartphones.
• Three acquisition configurations were tested: single-device supine (M1), single-device seated (M2), and synchronized dual-device (M3).
• RR intervals were calculated using consistent filtering and peak detection methods across all configurations.

Main Results:

• The agreement between accelerometer- and PPG-derived RR intervals varied significantly across the tested configurations (Kruskal-Wallis H = 15.98, p < .001).
• The synchronized dual-device configuration demonstrated superior performance with a lower median RR agreement error (38.33 ms) compared to single-device configurations (median 107 ms).

Conclusions:

• The method of data acquisition using smartphones significantly affects the reliability of smartphone-derived RR intervals.
• Standardized acquisition protocols are essential for ensuring dependable cardiac monitoring using smartphone technology.
• Dual-device synchronized recordings show promise for enhancing the accuracy of mobile cardiovascular monitoring.