Table 2.
Neural network prediction error summary
| Network | # skin temp inputs | Reference rhythm | Prediction method | n | Prediction Error (minutes) | Prediction Error Absolute Values (minutes) | Correlation with measured phase | Percentage predicted within range | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mean | Median | SD | Range | Mean Absolute | Median Absolute | SD Absolute | Min | Max | RMSE | r | p | ± 15 mins | ± 30 mins | ± 60 mins | ± 120 mins | |||||
| Trained networks | ||||||||||||||||||||
| Fixed sleep | 11 | Melatonin | cross validation | 15 | 5.67 | 17.82 | 50.36 | 166.03 | 42.49 | 39.43 | 25.24 | 14.21 | 84.91 | 48.98 | 0.43 | 0.12 | 6.67 | 40.00 | 73.33 | 100.00 |
| Fixed sleep | 1 | Melatonin | cross validation | 15 | 1.33 | 11.48 | 53.00 | 194.61 | 40.86 | 27.01 | 31.97 | 7.06 | 106.29 | 51.23 | 0.41 | 0.15 | 26.67 | 53.33 | 66.67 | 100.00 |
| Fixed + habitual sleep | 11 | aMT6s | cross validation | 26 | 1.88 | −1.46 | 66.46 | 256.29 | 48.71 | 37.76 | 44.19 | 0.81 | 151.32 | 65.20 | 0.46 | 0.07 | 26.92 | 42.31 | 65.38 | 92.31 |
| Fixed + habitual sleep | 1 | aMT6s | cross validation | 27 | −0.91 | −4.16 | 66.83 | 277.90 | 50.85 | 40.98 | 42.22 | 2.74 | 152.60 | 65.59 | 0.45 | 0.03 | 22.22 | 37.04 | 66.67 | 88.89 |
| Diurnal sleep | 1 | aMT6s | cross validation | 56 | −0.95 | −3.27 | 92.36 | 604.60 | 62.84 | 48.60 | 67.16 | 0.42 | 312.66 | 91.54 | 0.42 | 0.01 | 19.64 | 41.07 | 66.07 | 87.50 |
| SWday | 1 | aMT6s | cross validation | 29 | 9.36 | −9.21 | 104.08 | 541.49 | 65.68 | 38.28 | 80.34 | 3.34 | 327.79 | 102.69 | 0.39 | 0.16 | 17.24 | 41.38 | 68.97 | 86.21 |
| SWnights | 1 | aMT6s | cross validation | 19 | −22.11 | −10.24 | 212.86 | 1013.81 | 143.29 | 115.28 | 155.42 | 1.50 | 605.48 | 208.36 | 0.04 | 0.84 | 21.05 | 31.58 | 42.11 | 52.63 |
| Predictions using final networks | ||||||||||||||||||||
| SWday | 1 | aMT6s | Fixed + habitual sleep | 29 | −2.85 | −0.41 | 145.69 | 884.74 | 81.87 | 50.11 | 119.55 | 0.41 | 561.90 | 143.18 | 0.46 | 0.08 | 24.14 | 37.93 | 68.97 | 82.76 |
| SWnight | 1 | aMT6s | Fixed + habitual sleep | 19 | 314.26 | 375.79 | 355.86 | 1245.97 | 437.37 | 403.83 | 170.18 | 198.53 | 695.89 | 467.69 | 0.23 | 0.36 | 0.00 | 0.00 | 0.00 | 0.00 |
| SWnight | 1 | aMT6s | Diurnal sleep | 19 | 317.70 | 358.75 | 337.00 | 1284.05 | 422.58 | 396.71 | 177.79 | 196.85 | 701.92 | 456.64 | 0.31 | 0.22 | 0.00 | 0.00 | 0.00 | 0.00 |
| Comparative estimation methods | ||||||||||||||||||||
| Diurnal sleep | - | aMT6s | mid-sleep | 29 | −29.45 | −43.44 | 104.19 | 790.70 | 73.20 | 79.27 | 60.75 | 0.50 | 542.90 | 107.38 | 0.25 | 0.17 | 14.29 | 26.79 | 50.00 | 91.07 |
| SWnight | - | aMT6s | mid-sleep | 19 | 413.13 | 436.30 | 185.67 | 853.40 | 427.17 | 436.30 | 148.38 | 133.40 | 720.00 | 450.92 | 0.34 | 0.09 | 0.00 | 0.00 | 0.00 | 0.00 |
| Diurnal sleep | - | aMT6s | normal range estimate | 29 | 11.05 | 3.31 | 150.15 | 807.18 | 115.15 | 100.43 | 95.76 | 1.40 | 542.90 | 174.66 | −0.04 | 0.75 | 8.93 | 14.29 | 33.93 | 57.14 |
| SWnight | - | aMT6s | normal range estimate | 19 | −55.73 | −52.96 | 206.87 | 854.11 | 150.01 | 96.40 | 149.40 | 4.42 | 545.78 | 208.92 | 0.12 | 0.57 | 5.26 | 5.26 | 26.32 | 63.16 |
| Diurnal sleep | - | aMT6s | random re-sampling | 29 | 0.00 | 0.00 | 130.92 | 900.00 | 95.71 | 88.39 | 87.50 | 0.00 | 469.00 | 129.75 | 0.10 | 0.43 | 8.93 | 19.64 | 30.36 | 64.29 |
| SWnight | - | aMT6s | random re-sampling | 19 | 0.00 | 11.00 | 235.99 | 1012.00 | 180.11 | 146.46 | 148.00 | 11.00 | 547.00 | 229.70 | 0.33 | 0.10 | 5.26 | 10.53 | 21.05 | 36.84 |
Note: all results are from networks using inputs of blue light irradiance combined with skin temperature. See Supplementary Table S3 for results using alternate input combinations. aMT6s = urinary 6-sulphatoxymelatonin, RMSE = root mean square error. Correlation coefficients were calculated using circular statistics.