Table 3.
Prediction Accuracy for Subjective Ratings for the Occurrence of Severe/Moderate Levels of Physiological Drowsiness Events in the Next 15 Minutes
| Item | Description | OR [95% CI]β | p | AUC [95% CI] | p |
|---|---|---|---|---|---|
| Severe drowsiness JDS > 4.5 | |||||
| KSS | Subjective sleepiness | 1.76 [1.32, 2.33] | <0.001 | 0.84 [0.75, 0.93] | <0.001 |
| LFA | Likelihood of falling asleep | 1.99 [1.42, 2.80] | <0.001 | 0.80 [0.70, 0.89] | <0.001 |
| SSQ1 | Struggle to keep eyes open | 2.06 [1.57, 2.71] | <0.001 | 0.89 [0.84, 0.95] | <0.001 |
| SSQ2 | Vision blurred | 2.22 [1.66, 2.97] | <0.001 | 0.90 [0.85, 0.96] | <0.001 |
| SSQ3 | Nodding off to sleep | 2.46 [1.81, 3.35] | <0.001 | 0.93 [0.89, 0.98] | <0.001 |
| SSQ4 | Difficulty keeping to middle of road | 2.31 [1.69, 3.15] | <0.001 | 0.90 [0.85, 0.95] | <0.001 |
| SSQ5 | Difficulty maintaining correct speed | 2.67 [1.85, 3.84] | <0.001 | 0.90 [0.84, 0.96] | <0.001 |
| SSQ6 | Mind wandering | 2.28 [1.63, 3.20] | <0.001 | 0.85 [0.74, 0.96] | <0.001 |
| SSQ7 | Reactions are slow | 2.51 [1.81, 3.48] | <0.001 | 0.91 [0.85, 0.97] | <0.001 |
| SSQ8 | Head dropping | 2.81 [1.99, 3.97] | <0.001 | 0.90 [0.80, 1.00] | <0.001 |
| SSQ global score | 1.12 [1.08, 1.17] | <0.001 | 0.88 [0.77, 0.99] | <0.001 | |
| Moderate drowsiness JDS ≥ 2.7 | |||||
| KSS | Subjective sleepiness | 1.30 [1.16, 1.46] | <0.001 | 0.68 [0.61, 0.76] | <0.001 |
| LFA | Likelihood of falling asleep | 1.63 [1.30, 2.05] | <0.001 | 0.66 [0.58, 0.74] | <0.001 |
| SSQ1 | Struggle to keep eyes open | 1.57 [1.32, 1.87] | <0.001 | 0.70 [0.62, 0.78] | <0.001 |
| SSQ2 | Vision blurred | 1.80 [1.45, 2.23] | <0.001 | 0.72 [0.65, 0.80] | <0.001 |
| SSQ3 | Nodding off to sleep | 1.81 [1.45, 2.27] | <0.001 | 0.71 [0.63, 0.78] | <0.001 |
| SSQ4 | Difficulty keeping to middle of road | 1.79 [1.44, 2.22] | <0.001 | 0.71 [0.63, 0.79] | <0.001 |
| SSQ5 | Difficulty maintaining correct speed | 1.64 [1.33, 2.01] | <0.001 | 0.66 [0.59, 0.75] | <0.001 |
| SSQ6 | Mind wandering | 1.45 [1.23, 1.71] | <0.001 | 0.67 [0.60, 0.75] | <0.001 |
| SSQ7 | Reactions are slow | 1.79 [1.44, 2.23] | <0.001 | 0.69 [0.61, 0.77] | <0.001 |
| SSQ8 | Head dropping | 1.78 [1.34, 2.33] | <0.001 | 0.62 [0.54, 0.70] | <0.001 |
| SSQ global score | 1.08 [1.08, 1.12] | <0.001 | 0.70 [0.62, 0.78] | <0.001 | |
| End-state drowsiness (EEG microsleeps) | |||||
| KSS | Subjective sleepiness | 1.24 [1.03, 1.49] | 0.026 | 0.65 [0.50, 0.80] | 0.044 |
| LFA | Likelihood of falling asleep | 1.63 [1.17, 2.26] | 0.004 | 0.70 [0.56, 0.84] | 0.007 |
| SSQ1 | Struggle to keep eyes open | 1.47 [1.17, 1.84] | <0.001 | 0.73 [0.60, 0.85] | 0.002 |
| SSQ2 | Vision blurred | 1.29 [1.02, 1.65] | 0.041 | 0.65 [0.51, 0.79] | 0.041 |
| SSQ3 | Nodding off to sleep | 1.30 [1.02, 1.66] | 0.038 | 0.68 [0.54, 0.81] | 0.016 |
| SSQ4 | Difficulty keeping to middle of road | 1.20 [0.91, 1.58] | n.s | 0.58 [0.42, 0.73] | n.s |
| SSQ5 | Difficulty maintaining correct speed | 1.02 [0.74, 1.41] | n.s | 0.52 [0.37, 0.66] | n.s |
| SSQ6 | Mind wandering | 1.20 [0.93, 1.55] | n.s | 0.63 [0.51, 0.75] | n.s |
| SSQ7 | Reactions are slow | 1.14 [0.86, 1.52] | n.s | 0.58 [0.43, 0.72] | n.s |
| SSQ8 | Head dropping | 0.59 [0.25, 1.36] | n.s | 0.42 [0.29, 0.55] | n.s |
| SSQ global score | 1.03 [0.99, 1.07] | n.s | 0.64 [0.50, 0.78] | n.s | |
β, post script note.
Continuous OR—change in odds of a severe/moderate event occurring in the next 15 minutes with each point increase on the predictor scale.