Table 6.
Kappa values and accuracy of manual sleep staging vs CReSS sleep staging in SHHS by sleep apnea severity subgroups.
| Sleep Stage Discrimination | No SDB (n = 82) | Mild SDB (n = 97) | Moderate SDB (n = 61) | Severe SDB (n = 56) | ||||
|---|---|---|---|---|---|---|---|---|
| Kappa (95% CI) | Percent Accuracy | Kappa (95% CI) | Percent Accuracy | Kappa (95% CI) | Percent Accuracy | Kappa (95% CI) | Percent Accuracy | |
| CReSS Applied to Heart Rate and Airflow Signals | ||||||||
| Wake/LS/DS/REM sleep | 0.613 (0.608–0.617) | 74.6 | 0.597 (0.592–0.601) | 74.1 | 0.546 (0.541–0.552) | 71.5 | 0.522 (0.515–0.528) | 71.9 |
| Wake/sleep | 0.681 (0.674–0.688) | 90.2 | 0.654 (0.648–0.661) | 89.7 | 0.635 (0.627–0.643) | 88.4 | 0.550 (0.542–0.559) | 83.5 |
| NREM sleep/REM sleep | 0.789 (0.782–0.795) | 93.0 | 0.776 (0.770–0.782) | 92.6 | 0.719 (0.710–0.728) | 91.5 | 0.692 (0.681–0.702) | 91.8 |
| LS/DS | 0.479 (0.469–0.490) | 82.3 | 0.461 (0.451–0.471) | 82.9 | 0.370 0.356–0.385) | 81.5 | 0.381 (0.362–0.401) | 89.0 |
| Wake/NREM sleep/REM sleep | 0.709 (0.705–0.714) | 84.9 | 0.691 (0.686–0.695) | 84.0 | 0.650 (0.644–0.656) | 82.1 | 0.576 (0.569–0.582) | 77.9 |
| CReSS Applied to Heart Rate, Airflow, and Thoracic Respiratory Effort Signals | ||||||||
| Wake/LS/DS/REM sleep | 0.666 (0.662–0.671) | 78.0 | 0.643 (0.639–0.648) | 77.0 | 0.612 (0.606–0.617) | 75.4 | 0.592 (0.586–0.598) | 76.0 |
| Wake/sleep | 0.741 (0.735–0.748) | 91.9 | 0.714 (0.708–0.720) | 91.4 | 0.719 (0.712–0.726) | 91.0 | 0.634 (0.626–0.641) | 86.3 |
| NREM sleep/REM sleep | 0.845 (0.840–0.851) | 94.8 | 0.816 (0.811–0.821) | 93.8 | 0.773 (0.766–0.781) | 92.9 | 0.752 (0.742–0.761) | 93.3 |
| LS/DS | 0.497 (0.487–0.507) | 82.9 | 0.479 (0.469–0.489) | 83.5 | 0.398 (0.384–0.412) | 82.4 | 0.386 (0.366–0.406) | 89.7 |
| Wake/NREM sleep/REM sleep | 0.771 (0.767–0.775) | 87.9 | 0.743 (0.739–0.747) | 86.6 | 0.723 (0.718–0.729) | 85.6 | 0.652 (0.646–0.658) | 81.7 |
Discriminations of wake/LS/DS/REM sleep and wake/NREM sleep/REM sleep are based on all epochs. For the discrimination of NREM sleep/REM sleep that does not include wake, we transformed the confusion matrix by removing the wake column and row; the same transformation was undertaken for the LS/DS discrimination by removing both wake and REM sleep. CI = confidence interval, CReSS = CardioRespiratory Sleep Staging, DS = deep sleep (corresponding to N3), LS = light sleep (corresponding to N1 + N2), NREM = non-REM, REM = rapid eye movement, SDB = sleep-disordered breathing, SHHS = Sleep Heart Health Study.