Correlation of Epworth Sleepiness Scale with multiple sleep latency test and its diagnostic accuracy in assessing excessive daytime sleepiness in patients with obstructive sleep apnea hypopnea syndrome

Background Excessive daytime sleepiness （EDS） is often associated with obstructive sleep apnea hypopnea syndrome （OSAHS） and contributes to a number of comorbidities in these patients. Therefore, early detection of EDS is critical in disease management. We examined the association between Epworth Sleepiness Scale （ESS） and multiple sleep latency test （MSLT） and diagnostic accuracy of ESS in assessing EDS in OSAHS patients. Methods The ESS, MSLT and overnight polysomnography were administered to 107 Chinese patients to assess EDS and its correlations with polysomnographic parameters. The diagnostic accuracy of ESS in classifying EDS （mean sleep latency （MSL） 〈10 minutes） was evaluated by calculating the area under ROC curve. Results As the severity of OSAHS increased, MSL decreased with increase in ESS score. Conversely, patients with worsening EDS （shorter MSL） were characterized by advanced nocturnal hypoxaemia and sleep disruption compared to those with normal MSL, suggesting EDS is associated with more severe OSAHS. There was a negative correlation between ESS score and MSL and both moderately correlated with some polysomnographic nocturnal hypoxaemic parameters. The area under ROC curve of ESS for identifying EDS was 0.80 （95% CI： 0.71 to 0.88） and ESS score 〉12 provided the best predictive value with a sensitivity of 80% and specificity of 69%. Conclusion The ESS score moderately correlates with MSL and our ROC study supports ESS as a screening strategy for assessing EDS in OSAHS.

A Polysomnography Study of Kleine-Levin Syndrome in a Single Center

Background： Kleine-Levin syndrome （KLS） is a rare sleep disorder characterized by recurrent episodes of hypersomnia. Polysomnographic （PSG） researches of KLS have been reported only in few publications in the past decades. This study aimed to investigate the characteristics of PSG of KLS. Methods： This study, which was conducted from March 2010 to July 2014, included seven patients diagnosed with KLS in the Sleep and Wake Disorder Center of Huashan Hospital, Fudan University （Shanghai, China）. PSG and multiple sleep latency tests （MSLT） were performed during their episodes and the results were evaluated. Results： Five of the seven patients were males, The mean age at KLS onset was 15.6 ：k 3.6 years. The number of episodes ranged from 2 to 7. The duration of episodes lasted from 4 to 11 days. The sleep architecture and proportion were normal in most of the patients. The average value of mean sleep latency was 6.9 4- 4.1 min. No sleep-onset rapid eye movement （SOREM） was detected in three of the patients, whereas one patient experienced one period of SOREM, and such episodes occurred twice in other two patients. Conclusions： We found that sleep architecture and proportion were normal in most KLS patients. However, the results of PSG and MSLT had no specificity for KLS patients.