ABSTRACT

BACKGROUND/AIMS

The aim of the present study was to find out whether Epworth Sleepiness Scale (ESS) is correlated with polysomnography (PSG) and which specific polysomnographic parameter is most closely associated with ESS scores and thus excessive daytime sleepiness.

MATERIAL and METHODS

The study included patients with an initial diagnosis of obstructive sleep apnea syndrome (OSAS). All patients completed a validated Turkish version of the ESS. Patients were divided into two groups based on their ESS scores as those with an ESS score below 10 and those scoring above 10. The differences in mean values of PSG parameters were compared between the two groups. Correlations between ESS scores and PSG parameters were investigated for all patients.

RESULTS

The study included 174 patients. The group with ESS scores above 10 was found to have significantly greater apnea-hypopnea index (AHI), arousal index, oxygen desaturation (ODI), and total sleep time spent with an oxygen saturation less than 90% in comparison to the group with ESS scores below 10. A moderate positive correlation between ESS scores and ODI and weak positive correlations between ESS scores and AHI and arousal index were found.

CONCLUSION

Given the finding that ODI had the strongest correlation with ESS, it can be concluded that as well as being closely related to the subjective symptoms of OSAS, ODI is the PSG parameter that best reflects excessive daytime sleepiness.