Table I.
Mean values (± SD) of sleep variables per group (in min)
| Control Group (n = 9) | REMD Group (n = 9) | T a | |
|---|---|---|---|
| Total sleep timeb | 347.3 (± 27.36) | 304.28 (± 34.01) | 2.96** |
| REM sleep amount | 52.3 (± 8.1) | 15.1 (± 9.2) | 9.14*** |
| NREM sleep amount | 292.9 (± 25.4) | 286.3 (± 34.6) | 0.46 |
| Stage 1 amount | 30.9 (± 19.6) | 37.8 (± 13.8) | 0.85 |
| Stage 2 amountc | 175.4 (± 26.5) | 151.4 (± 33.2) | 1.69 |
| Stage 3 amount | 39.9 (± 12.0) | 36.2 (± 13.4) | 0.61 |
| Stage 4 amountc | 46.7 (± 31.0) | 60.9 (± 24.9) | 1.08 |
| Latency wake to S1 | 10.8 (± 9.8) | 7.4 (± 5.3) | 0.90 |
| Latency S1 to S2 | 4.6 (± 2.7) | 11.0 (± 24.8) | 0.77 |
| Latency S2 to S3 | 10.1 (± 3.9) | 9.1 (± 3.8) | 0.56 |
| Latency S2 to S4 | 18.0 (± 8.7) | 13.9 (± 4.4) | 1.25 |
**
P < 0.01;
***
P < 0.001.
a
Undirected independent samples t‐tests (df = 16), with equal variances assumed, except for REM sleep amount (df = 8.5).
b
Total sleep time was subtracted from the average total sleep time in the week preceding the experiment (according to sleep diaries), to obtain a sleep restriction measure that was included as a covariate in the statistical SCR and fMRI analyses.
c
S2 and S4 amount were also included as a covariate in the statistical analyses.