Background: Patients with obstructive sleep apnoea syndrome (OSAS) suffer from disrupted sleep. Impaired nightly sleep leads to increase physical and mental fatigue. The effect of long term continuous positive airway pressure (CPAP) on mental fatigue in OSAS patients, assessed by Maastricht Questionnaire (MQ), has not been investigated yet.
Methods: In order to evaluate the role of CPAP in improving mental fatigue of patients with OSAS, we studied 35 patients (26 males, age < 65 years at the time of the diagnosis) affected by OSAS, established by polysomnography (PSG). Patients were divided into two groups; 19 subjects (15 males), who refused CPAP therapy, and 16 patients (11 males) well matched for sex, age, body mass index (BMI), neck circumference, duration of follow up, and severity of disease, who had been treated with CPAP for at least two years.
Results: All patients had severe OSAS with Respiratory Disturbance Index (RDI), of 48 +/- 20.9 (range 22-90) and 61.48 +/- 18.6 (range 34-101) respectively, for group one (untreated patients) and group two (CPAP treatment). In addition, all patients had severe impairment of mental fatigue and of daytime sleepiness, demonstrated by high values of MQ score (32.17 +/- 15.33 and 37.36 +/- 12.4, respectively) and Epworth Sleepiness Scale (ESS) (14.21 +/- 4.77 and 15.06 +/- 6.07 respectively). There was no statistical significant difference in the group one at baseline and after follow-up, in terms of BMI, MQ score, ESS, and RDI. In the CPAP group (group two), the patients reported a significant improvement of the quality of their mental health (MQ 37.36 +/- 12.4 vs. 16.41 +/- 9.02; p < 0.0001) and sleepiness (ESS 15.06 +/- 6.07 vs. 4.13 +/- 3.93; p < 0.0001) with a stable BMI. There was significant correlation between the severity of sleep apnoea, expressed as RDI, and MQ at admission compared to at the end of follow-up (r = 0.4, p < 0.05).
Conclusions: This study demonstrates an evident deterioration of mental fatigue in patients with OSAS, directly correlated to the severity of nocturnal disorder breathing; however supports the hypothesis that long-term CPAP therapy significantly improves sleepiness and mental fatigue.