Table 4.
Comparison of Oura, Fitbit, and Apple Watch to PSG with respect to sleep/wake and sleep stages.
| Oura n = 35 Mean (SD) |
PSG n = 35 Mean (SD) |
Fitbit n = 33 Mean (SD) |
PSG n = 33 Mean (SD) |
Apple Watch n = 29 Mean (SD) |
PSG n = 29 Mean (SD) |
|
|---|---|---|---|---|---|---|
| Total Sleep Time (min) | 421 (34) | 430 (41) | 428 (23) | 431 (40) | 442 (35) | 434 (40) |
| Wake (min) | 59 (34) | 50 (41) | 49 (26) | 49 (40) | 39 (35) * | 46 (40) |
| Light Sleep (min) | 233 (28) | 239 (41) | 258 (37) * | 240 (41) | 289 (24) * | 244 (38) |
| Deep Sleep (min) | 95 (21) | 95 (35) | 79 (27) * | 94 (36) | 51 (18) * | 94 (38) |
| REM (min) | 93 (25) | 96 (21) | 90 (28) | 97 (21) | 102 (22) | 96 (21) |
| Sleep Latency (min) | 18 (25) * | 13 (22) | 13 (21) | 13 (22) | 17 (26) | 15 (23) |
| WASO (min) | 42 (26) | 38 (37) | 40 (15) | 36 (35) | 22 (23) * | 32 (33) |
| Sleep Efficiency (%) | 88% (7%) | 90% (9%) | 89% (5%) | 90% (8%) | 92% (7%) | 90% (8%) |
Notes. Missing data were reassigned as wake (see section on wake interpolation). Sample size for sleep latency n = 34 for PSG vs. Oura, n = 32 for PSG vs. Fitbit, and n = 29 for PSG vs. Apple Watch. * Indicates significant difference between the device and PSG using paired t-tests.