Characteristic | Asymptomatic OSA | Symptomatic OSA | p-value |
Subjects n | 19 | 29 | |
AHI | 14±2 | 27±3 | <0.01 |
Arousal index# | 11±1 | 14±2 | 0.22 |
Sleep efficiency % | 76±3 | 76±2 | 0.96 |
Stage wake min | 102±16 | 103±9 | 0.59 |
Total sleep time min | 301±14 | 316±8 | 0.43 |
Sleep stage 1 % of total sleep time | 9.7±2.4 | 10.9±2.9 | 0.89 |
Sleep stage 2 % of total sleep time | 53.5±3.1 | 57.6±3.2 | 0.25 |
Delta sleep stage 3+4 % of total sleep time | 24.0±2.7 | 19.9±2.1 | 0.27 |
Sleep stage REM % of total sleep time | 12.8±1.5 | 11.6±1.4 | 0.57 |
Minimum nocturnal Sa,O2 % | 83±1 | 77±2 | <0.05 |
Mean nocturnal Sa,O2 % | 94±0 | 93±0 | <0.05 |
Sa,O2<90% % | 5±2 | 19±4 | <0.05 |
ESS | 5±1 | 10±2 | 0.08 |
ODI | 12±3 | 26±3 | <0.01 |
Change of reflective index¶ during the night % of awake value | 5±2 | 10±3 | 0.17 |
Data are presented as mean±sem, unless otherwise stated. AHI: apnoea/hypopnoea index (mean number of episodes of apnoea and hypopnoea per hour of sleep); REM: rapid eye movement; Sa,O2: arterial oxygen saturation; ESS: Epworth Sleepiness Scale; ODI: oxygen desaturation index. #: the arousal index is the mean number of arousal reactions per hour of sleep; ¶: reflective index at 05.00 h is given as percentage of the reflective index of the patient awake in the lying position before the start of the polysomnography.