Reliability and validity studies of the Turkish version of the Epworth Sleepiness Scale

Abstract

The Epworth Sleepiness Scale (ESS) is a self-administered eight-item questionnaire that is widely used in English speaking countries for assessment of daytime sleepiness in adults. The aim of this study was to investigate the reliability and validity of the ESS in the Turkish language. The Turkish version of the ESS (ESStr) was applied to 194 healthy controls and 150 consecutive subjects attending the sleep centre with symptoms of sleep-disordered breathing. Test-retest reliability of the ESStr was tested in a separate group of 30 subjects. The ESStr scores of 60 subjects with mild to severe obstructive sleep apnoea (OSA) were compared with the ESStr scores of 60 healthy controls matched for age, gender, and body mass index (BMI). Concurrent validity with the Functional Outcomes of Sleep Questionnaire (FOSQtr) was also assessed in 12 subjects. The questionnaire had a high level of internal consistency as measured by Cronbach's alpha (> or =0.86). The test-retest intraclass correlation coefficient was r = 0.81 (95% confidence interval: 0.64-0.90) (p < 0.001) and Spearman's correlation coefficient was r = 0.80 (p = 0.01). The control group had lower ESStr scores than subjects with sleep-disordered breathing (3.6 +/- 3 vs 12.6 +/- 6, respectively; p < 0.001). Subjects with mild sleep-disordered breathing also had lower scores of the ESStr than those with moderate and severe sleep-disordered breathing (10 +/- 6.2 vs 14 +/- 5. and 10 +/- 6.2 vs 16 +/- 5.4, respectively; both p < 0.05), but there were no significant differences between moderate and severe subjects with sleep apnoea. There were significant correlations between the ESStr and total FOSQtr and its subscales (r = -0.22 to r = -0.92; all p = 0.05). Factor analysis of item scores showed that the ESStr had only one factor. The ESStr is a reliable and valid measure of daytime sleepiness. These features and the simplicity of the ESStr make it a valuable measure for clinical management and research.

Portuguese-language version of the Epworth sleepiness scale: validation for use in Brazil

“…For the 135 individuals assessed in the present study, the scores obtained on the ESS-BR showed internal consistency similar to that of translations validated elsewhere, (24)(25)(26)(27)(28) despite the cultural and language differences among the populations analyzed. Comparing the ESS-BR scores obtained in the present study with those obtained in studies applying the original ESS, we found the scores to be similar for the control and OSAHS groups.…”

“…(25)(26)(27)(28) In one study, (19) the ESS scores were significantly higher for patients with severe OSAHS than for those with mild or moderate OSAHS (p < 0.001), although no statistically significant difference was found between the mild and moderate forms. Unlike other validation studies, the present study evaluated only individuals submitted to polysomnography, which enhanced the stringency of the selection of the groups.…”

A systematic review of screening questionnaires for obstructive sleep apnea

“…The characteristics of the included studies are summarized in Table 1. The excluded studies 11,[16][17][18][19][20][22][23][24] and the reasons for their exclusion are listed in Table 2.…”

Effects of Circadian Rhythm on Balance Performance

“…A validity and reliability analysis of the Turkish version was conducted by Pündük, Gür, and Ercan [18]. The Turkish version of the Epworth Sleepiness Scale was additionally used to determine sleep quality [19].…”