Table 1. Factor Analysis of Sleep-Wake Traits.
| Trait | Factor 1 | Factor 2 | Factor 3 | Factor 4 | Factor 5 |
| Fragmentation | REM Sleep | State Amount | Power Bands | Latency | |
| nb Wake | −0.82 | −0.20 | 0.03 | 0.26 | −0.04 |
| db Wake | 0.77 | 0.22 | −0.31 | −0.23 | 0.09 |
| nb NREM | −0.96 | −0.07 | 0.19 | −0.02 | −0.08 |
| db NREM | 0.95 | 0.13 | 0.22 | 0.02 | 0.09 |
| db TS | 0.96 | 0.08 | 0.19 | 0.03 | 0.10 |
| # Arousals | −0.69 | 0.13 | 0.27 | −0.30 | −0.08 |
| # Shifts | −0.95 | −0.13 | 0.19 | −0.02 | −0.09 |
| Onset REM | 0.85 | 0.16 | 0.33 | 0.04 | 0.11 |
| REM min | −0.17 | −0.91 | −0.02 | 0.08 | 0.02 |
| % REM/TS | −0.14 | −0.83 | −0.43 | 0.10 | 0.05 |
| nb REM | −0.21 | −0.89 | 0.05 | 0.00 | −0.21 |
| Inter REM | 0.03 | 0.85 | −0.09 | 0.05 | 0.19 |
| Wake min | 0.06 | 0.04 | −0.98 | 0.05 | 0.08 |
| NREM min | −0.03 | 0.12 | 0.98 | −0.06 | −0.09 |
| NREM rel Delta | 0.03 | −0.02 | 0.01 | 0.81 | 0.03 |
| REM rel Theta I | 0.14 | 0.10 | 0.02 | −0.78 | 0.00 |
| REM rel Theta II | −0.07 | −0.06 | 0.07 | −0.83 | 0.02 |
| lat NREM | 0.18 | −0.07 | −0.01 | −0.14 | 0.86 |
| lat REM | 0.10 | 0.18 | −0.02 | −0.02 | 0.87 |
| db REM | 0.04 | 0.14 | −0.11 | 0.15 | 0.39 |
| Proportion of Total Variance Explained | 31.4% | 16.5% | 12.9% | 11.2% | 9.1% |
| TOTAL | 81.1% |
Factor loadings (Statistica, StatSoft, Inc.) of the 20 sleep-wake variables in the 24-hr period are shown with the factor-determining loading values bolded (generally greater than ±0.75). The 5 factors account for 81 percent of the total variance in the data. See Supporting Information for complete trait descriptions, and Supporting Information Table S2 for a 1000× bootstrap-obtained estimate of the 95% confidence intervals of the factor loading values.