Assessment of Physiological Signals from Photoplethysmography Sensors Compared to an Electrocardiogram Sensor: A Validation Study in Daily Life

Figure A1. Impact of dominant vs. non-dominant wrist on accuracy of PPG-derived HR and HRV features.

Figure 1. Study design, device attachments, and continuous data collection periods.

Figure 2. Data consideration for the reliability assessment of the HR and HRV features.

Figure 3. Validation workflow of wearable PPG-based devices for HR and HRV.

Figure 4. R-R interval data coverage—where the height of the bars indicates the average coverage values while the whiskers correspond to 95% confidence intervals.

Figure 5. Usability evaluation of devices. Participants completed an end-of-study survey comprising a 13-item questionnaire assessing the usability of each device. Figure here shows abbreviated versions of the questions described in Section 2.4.

Figure 6. Bar plot showing the availability of 5-min epochs, which are valid for both devices, across days and participants.

Figure 7. Scatter and Bland–Altman plots showing the performance of the PPG devices compared to ECG device for (A) mean N-N intervals (top) and (B) HR (bottom) across 5-min epochs.

Figure 8. Impact of coverage within a 5-min epoch on the accuracy of PPG-derived HR and HRV features.

Figure 9. Impact of body posture on accuracy of PPG-derived HR and HRV features.

Figure 10. Impact of daily life activities on accuracy of PPG-derived HR and HRV features.

Figure 11. Impact of mobility on accuracy of PPG-derived HR and HRV features.