Objective: The purpose of this study was to assess a simplified maintenance of wakefulness test (Oxford SLEep Resistance test, OSLER test) in evaluating excessive daytime sleepiness.
Methods: Seventy-four snorers with or without obstructive sleep apnea-hypopnea syndrome (OSAHS) were studied. Two OSLER tests were performed in the afternoon with a gap of 30 minutes. Epworth sleepiness scale (ESS) was also recorded. An overnight sleep study using a multi-channel system was performed to distinguish nonapneic snorers (snorer group, n = 43) from OSAHS patients (OSAHS group, n = 31). The OSLER test was repeated in the OSAHS group after two month treatment with nasal continuous positive airway pressure (CPAP).
Results: There was a significant difference in sleep latency measured by the OSLER test between the OSAHS group and the snorer group (16.03 +/- 12.27 vs 25.70 +/- 14.62, P < 0.01). A significant correlation was found between sleep latency and ESS (r = -0.45, P < 0.01). Twenty-five of the 31 patients in the OSAHS group were treated with CPAP for two months. Sleep latency increased from 16.20 +/- 12.98 to 36.38 +/- 21.10 after treatment (P < 0.01).
Conclusion: The OSLER test appears useful in assessing excessive daytime sleepiness.