Table 2.
Agreement metrics for HB vs. PSG and ACT vs. PSG
| Sleep Metric | Mean (SD) | r a | Bias (SD)b [95% CI] |
p value | LoA lower bound [95% CI] | LoA upper bound [95% CI] |
MDC | ICC (95% CI) |
|---|---|---|---|---|---|---|---|---|
| Headband c | ||||||||
| TST | 358.6 (96.4) | 0.9 | −6.7 (40.7) [−17.3, 2.9] |
0.20 | −86.0 [−112.8, −57.1] |
72.6 [55.9, 87.1] |
79.3 | 0.91 (0.86, 0.95) |
| WASO | 92.8 (66.9) | 0.8 | 9.4 (37.6) [−0.4, 18.3] |
0.06 | −64.3 [−74.1, −55.4] |
83.1 [73.2, 92.1] |
73.7 | 0.82 (0.73, 0.89) |
| SOLd | 28.4 (23.37) | 0.6 | −2.3 (24.1) [−9.5, 3.4] |
0.49 | −49.5 [−78.3, −21.6] |
44.9 [20.5, 64.5] |
47.2 | 0.59 (0.38, 0.74) |
| SE (%) | 75.7 (14.3) | 0.8 | −1.1 (7.8) [−2.9, 0.9] |
0.29 | −16.3 [−18.2, −14.3] |
14.2 [12.4, 16.1] |
15.3 | 0.84 (0.75, 0.90) |
| Lighte | 251.6 (83.2) | 0.2 | −34.9 (60.0) [−50.6, −20.8] |
<0.01 | −152.5 [−198.4, −106.4] |
82.6 [53.0, 109.4] |
117.5 | 0.66 (0.50, 0.78) |
| Deepf | 23.9 (26.8) | 0.4 | 5.5 (25.8) [−1.0, 11.9] |
0.10 | −45.1 [−63.4, −28.3] |
56.1 [41.4, 69.1] |
67.8 | 0.51 (0.31, 0.67) |
| REMg | 83.2 (47.5) | 0.4 | 22.7 (40.2) [12.4, 33.0] |
<0.01 | −56.0 [−73.9, −38.2] |
101.4 [83.6, 119.3] |
78.7 | 0.44 (0.22, 0.62) |
| Actigraphy h | ||||||||
| TST | 417.3 (100.2) | 0.8 | 52.0 (55.4) [38.0, 65.7] |
< 0.01 | −56.6 [−95.8, −22.9] |
160.5 [126.1, 191.6] |
108.6 | 0.73 (0.60, 0.83) |
| WASO | 55.5 (44.0) | 0.5 | −27.9 (54.6) [−41.3, −13.9] |
< 0.01 | −134.8 [−163.4, −103.4] |
79.0 [46.7, 118.1] |
106.9 | 0.41 (0.18, 0.59) |
| SOL | 2.4 (5.4) | 0.3 | −24.1 (27.4) [−31.2, −17.7] |
< 0.01 | −77.7 [−98.6, −55.3] |
29.5 [16.8, 40.4] |
53.6 | −0.17 (−0.40, 0.08) |
| SE (%) | 87.7 (9.1) | 0.6 | 10.9 (10.9) [8.2, 13.6] |
< 0.01 | −10.3 [−18.4, −3.6] |
32.2 [26.0, 38.0] |
21.3 | 0.28 (0.03, 0.49) |
Abbreviations. ACT=Actigraphy; CI=Confidence Interval; HB=Headband; ICC=Intraclass Correlation Coefficient; LoA=Limit of agreement; MDC=Minimum detectable change; PSG=Polysomnography; REM=Rapid eye movement sleep; SD=Standard Deviation; SE=Sleep efficiency; SOL=Sleep onset latency; TST=Total Sleep Time; WASO=Wake After Sleep Onset.
Pearson correlation coefficient
Difference= device (headband or actigraphy) – polysomnography
Apart from REM sleep, all HB variables showed proportional bias and non-normality. SOL and deep sleep showed heteroscedasticity. Classic bias and LoA estimates are reported for consistency and comparability across metrics. Bias and LoAs were reported using bootstrapped confidence intervals except for REM sleep.
n=51; 10 participants removed for sleep onset that preceded start of polysomnography.
N1 and N2 sleep stages; mean (SD) of 69.8 (12.5) and 79.1 (9.3) percent in headband and polysomnography, respectively.
N3 sleep stage; mean (SD) of 6.9 (8.7) and 4.7 (6.3) percent in headband and polysomnography, respectively.
Mean (SD) of 23.3 (12.6) and 16.2 (8.6) percent in headband and polysomnography, respectively.
All ACT variables showed proportional bias and non-normality. TST and SOL showed heteroscedasticity. Classic bias and LoA estimates are reported for consistency and comparability across metrics. Bias and LoAs were reported using bootstrapped confidence intervals.