The Epworth Sleepiness Scale: translation and validation study of the Iranian version.
OBJECTIVE
The main purpose of this study was to assess the reliability and validity of the Iranian version of the Epworth Sleepiness Scale (ESS-IR).


METHODS
This was a cross-sectional study of 507 suspicious patients either to obstructive sleep apnea (n = 466) or narcolepsy (n = 41) in order to carry out a psychometric evaluation of the ESS-IR by performing reliability, validity, and responsiveness analyses. Reliability of the ESS-IR was assessed by internal consistency and test-retest reliability. Validity of the instrument was assessed using several statistical approaches including construct validity (exploratory factor analysis), discriminant validity, and criterion validity. Responsiveness of the ESS-IR was assessed by comparing the ESS-IR total score before and after 6-9 months of continues positive airway pressure (CPAP) treatment in 16 patients with obstructive sleep apnea (OSA).


RESULTS
The ESS-IR had an acceptable internal consistency and test-retest reliability. Factor analysis in both groups showed a two-factor solution for the ESS-IR, but the first factor showed statistically significant loads in all items. In addition, the ESS-IR discriminated well between patients with and without OSA. There is a fair correlation between the ESS-IR total score and multiple sleep latency test results that is not significant at all. Finally, the ESS-IR was found to be responsive to change where the total score was significantly decreased after CPAP treatment (P < 0.001).


CONCLUSIONS
The findings suggest that the ESS-IR is a reliable and valid measure for evaluating daytime sleepiness and now can be used in research and clinical settings in Iran.
Tehran University of Medical Sciences, Tehran, Iran.
Khosro
K
Sadeghniiat Haghighi
Ali
A
Montazeri
Ahmad
A
Khajeh Mehrizi
Omid
O
Aminian
Ania
A
Rahimi Golkhandan
Maryam
M
Saraei
Mojtaba
M
Sedaghat
D000328:Adult; D003431:Cross-Cultural Comparison; D003430:Cross-Sectional Studies; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007492:Iran; D008297:Male; D008875:Middle Aged; D009290:Narcolepsy / Q000175:diagnosis* / Q000453:epidemiology; D017286:Polysomnography; D011594:Psychometrics / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000453:epidemiology; D011795:Surveys and Questionnaires; D014175:Translating