Table 3. Polysomnographically assessed sleep parameters in the Moderate Light and Bright light group.
| Moderate Light | Bright Light | Moderate vs. Bright | |
| Sleep Latency (min) | 4.6 (1.6) | 18.4 (9.8) | P = 0.04 |
| REMS Latency (min) | 49.2 (9.4) | 64.5 (5.3) | NS |
| Total Sleep Time (min) | 348.4 (12.6) | 380.6 (19.7) | NS |
| Wake After Sleep Onset (min) | 128.0 (12.7) | 81.3 (19.0) | NS |
| Stage 1 (min) | 33.5 (3.2) | 39.8 (2.9) | NS |
| Stage 2 (min) | 147.1(8.6) | 187.8 (12.2) | P = 0.02 |
| Stage 3 (min) | 32.0 (4.4) | 37.9 (6.1) | NS |
| Stage 4 (min) | 70.2 (11.6) | 31.2 (13.5) | P = 0.05 |
| Slow Wave Sleep (min) | 102.1 (11.7) | 69.1 (17.9) | NS |
| REM Sleep (min) | 65.6 (4.5) | 83.9 (8.8) | NS |
| Movement Time (min) | 2.8 (1.0) | 3.4 (1.2) | NS |
| Stage 1% | 9.9 (0.9) | 10.9 (0.8) | NS |
| Stage 2% | 42.2 (2.4) | 49.8 (3.1) | NS |
| Slow Wave Sleep % | 29.4 (2.9) | 17.8 (3.9) | P = 0.4 |
| REM Sleep % | 18.6 (1.0) | 21.6 (1.9) | NS |
Mean and SEMS for sleep parameters for the two treatment groups. Data represent the averages of sleep episodes 7 and 8 for all subjects, with the exception of subject 1041 from the Bright Light group in whom only sleep episode 7 was included. n = 7 in each condition. % represents the percentage of that sleep stage expressed relative to total sleep time. P values indicate the significance of the difference between the Treatments as assessed in a two-factor Mixed Model ANOVA with factors Treatment and Sleep period. Sleep latency data were log-transformed prior to statistical tests.