Table 5. Correlation and effect size metrics measuring agreement between the SDNN, lnSDNN, RMSSD, and pNN50 values derived from the rPPG recordings and corresponding reference (PPG) recordings.
| 10s-1 | 10s-2 | 10s-3 | avg10s | 30s-1 | 30s-2 | avg30s | 60s | |
|---|---|---|---|---|---|---|---|---|
| Spearman coefficient* | ||||||||
| SDNN | 0.708 | 0.803 | 0.750 | 0.763 | 0.766 | 0.778 | 0.761 | 0.841 |
| RMSSD | 0.358 | 0.536 | 0.507 | 0.536 | 0.484 | 0.579 | 0.544 | 0.529 |
| pNN50 | – | – | – | – | 0.584 | 0.679 | 0.666 | 0.657 |
| Pearson correlation coefficient* | ||||||||
| lnSDNN | 0.654 | 0.787 | 0.790 | 0.776 | 0.737 | 0.787 | 0.790 | 0.842 |
| Cliff’s delta | ||||||||
| SDNN | 0.060 | 0.041 | 0.124 | 0.106 | 0.015 | 0.100 | 0.062 | 0.050 |
| RMSSD | −0.003 | 0.098 | 0.015 | 0.047 | −0.011 | 0.104 | 0.061 | 0.068 |
| pNN50 | – | – | – | – | 0.082 | 0.080 | 0.084 | 0.094 |
| Cohen’s d | ||||||||
| lnSDNN | 0.029 | 0.050 | 0.200 | 0.114 | −0.013 | 0.160 | 0.080 | 0.045 |
Note:
*
p < 0.05; 10s-1, 10s-2, and 10s-3 denote the first, second, and third group, of 10 s recordings, 30s-1 and 30s-2 the first and second group, of 30 s recordings, 60s the group of 60 s recordings, avg10s the average of the three groups of 10 s recordings, and avg30s the average of the two groups of 30 s recordings.