Nonparametric regression showing relationships between the Epworth Sleepiness Scale(ESS) score and nocturnal variables in obstructive sleep apnoea/hypopnoea syndrome patients
| Subjective sleepiness variables | ESS score |
| Respiratory variables | |
| AHI | -0.20 |
| AHI non-REM | -0.18 |
| AHI REM | 0.09 |
| AI | -0.07 |
| HI | -0.15 |
| ODI >4% | -0.11 |
| Minimal sleep Sa,O2 | -0.35 |
| Time with sleep Sa,O2 <80% | -0.18 |
| Time with sleep Sa,O2 <90% | 0.20 |
| Polysomnographic variables | |
| AwI | 0.15 |
| ArI | -0.46 |
| Sleep stage changes index | 0.20 |
Data are presented as Spearman coefficient r (rho) values. AHI: apnoea/hypopnoea index; REM: rapid eye movement; AI: apnoea index; HI: hypopnoea index; ODI: oxygen desaturation index; Sa,O2: arterial oxygen saturation; AwI: awakening index; ArI: arousal index.