| Characteristic | ⩽18 years (n = 20) | 19–30 years (n = 10) | ⩾31 years (n = 16) | p Value |
| Polysomnography | ||||
| Total sleep time | 481.9 (21.5) | 395.8 (30.2) | 313.7 (21) | <0.001 |
| Sleep onset latency | 20.8 (4.3) | 23.0 (7.7) | 18.7 (6.3) | NS |
| % Sleep efficiency | 89.1 (3.0) | 74.8 (7.8) | 76.8 (3.6) | 0.05 |
| % Stage 2 | 47.0 (2.1) | 55.2 (1.9) | 54.3 (3.6) | NS |
| % SWS | 26.2 (1.4) | 18.9 (0.9) | 18.8 (1.7) | <0.005 |
| % REM | 19.5 (1.3) | 16.3 (2.3) | 11.5 (1.5) | <0.01 |
| SAS diagnosis (%) | ||||
| SAS | 60 | 60 | 81 | 0.05 |
| OSAS | 35 | 40 | 69 | <0.01 |
| Severe OSAS | 0 | 0 | 31 | <0.05 |
| CSAS | 25 | 20 | 13 | NS |
| Severe CSAS | 0 | 0 | 6 | NS |
| Respiratory events | ||||
| AHI | 2.6 (0.5) | 5.64 (1.6) | 26.4 (6.6) | <0.001 |
| OAI | 0.2 (0.07) | 0.48 (0.2) | 6.7 (2.4) | <0.005 |
| HI | 1.6 ( 0.4) | 3.84 (1.5) | 16.4 (4.6) | <0.005 |
| CAI | 0.8 (0.2) | 1.31 (0.8) | 3.3 (1.7) | NS |
| O2 saturation | ||||
| O2 mean saturation | 97.0 (0.2) | 96.15 (0.4) | 92.9 (0.9) | <0.001 |
| O2 min saturation | 84.7 (2.1) | 89.08 (1.6) | 80.7 (2.7) | NS |
| TTS (%) with SaO2 <90% | 1.0 (0.5) | 0.4 (0.3) | 13.1 (5.3) | 0.05 |
AHI, apnoea hypopnoea index; CAI, central apnoea index; CSAS, central sleep apnoea syndrome; HI, hypopnoea index; OAI, obstructive apnoea index; OSAS, obstructive sleep apnoea syndrome; REM, rapid eye movements; SAS, sleep apnoea syndrome; SWS, slow wave sleep.
Results are expressed as mean (SEM) or %.
TTS (%) with SaO2 <90%, mean (SEM): percentage of sleep time spent with SaO2 below the threshold of 90%. We used this latter criterion as an indicator of SAS severity. The value for each patient corresponds to drops of SaO2 below 90% following apnoeic events with return to normal SaO2 after the drop. It also corresponds to long sustained desaturations below 90% for two patients who also presented with central alveolar hypoventilation.
Analysis of the effect of age group on continuous variables was tested by one way ANOVA with corresponding p significance values. Pearson χ2 tests were used for dichotomous variables.