Quality of Life Research

, Volume 11, Issue 8, pp 817–821 | Cite as

Validation of a Chinese version of the Epworth sleepiness scale

  • Ning-Hung Chen
  • Murray W. Johns
  • Hseuh-Yu Li
  • Chia-Chen Chu
  • Shu-Cheng Liang
  • Yu-Hsiang Shu
  • Ming-Lung Chuang
  • Pa-Chun Wang


Epworth sleepiness scale (ESS) is widely used to evaluate degree of somnolence among Chinese patients with sleep-disordered breathing. Yet no Mandarin–Chinese translation has ever reported its validation data. In this study we translated and validated the ESS into Mandarin Chinese (CESS). We found, in 31 bilingual patients' responses to the CESS and the English ESS obtained 1–2 weeks apart did not differ significantly (10.5 ± 3.7 vs. 9.6 ± 3.9, p = 0.32, Wilcoxon's signed rank test) and were significantly correlated (Spearman's ρ = 0.67, p = 0.0004). A total of 359 sleep-disordered breathing subjects were enrolled into the validation study in a prospective manner. The CESS showed acceptable internal consistency (Cronbach's α = 0.81). Thirty out of these patients answered CESS twice at an interval of 2–4 weeks, to yield an acceptable level of test–retest reliability (ρ = 0.74, p = 0.001). The respiratory disturbance indices obtained from 251 out of 359 subjects were significantly correlated with their CESS scores (ρ = 0.22, p < 0.001). The standard response mean of CESS was 0.86 as obtained from 94 out of 359 subjects who had initial control of their symptoms at 3 months after radio-frequency palate surgery. We conclude that the CESS is reliable in both a linguistic and a test–retest sense, and appears to be valid and sensitive to clinical change. The CESS could be used to advantage among other Mandarin-speaking subjects as a standardised screening test of sleepiness in daily life.

Epworth Mandarin-Chinese Sleepiness 


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  1. 1.
    Kryger M, Roth T, Dement W. Principles and Practice of Sleep Medicine, 3rd edn. Philadelphia: W.B. Sanders, 2000.Google Scholar
  2. 2.
    Thorpy MT. The clinical use of the multiple sleep latency test. Sleep 1992; 15: 268–276.Google Scholar
  3. 3.
    Chervin RD, Aldrich MS. The Epworth sleepiness scale may not reflect objective measures of sleepiness or sleep apnea. Neurology 1999; 52: 125–131.Google Scholar
  4. 4.
    Johns MW. Sensitivity and specificity of the multiple sleep latency test (MSLT), the maintenance of wakefulness test and the Epworth sleepiness scale: Failure of the MSLT as a gold standard. J Sleep Res 2000; 9: 5–11.Google Scholar
  5. 5.
    Fujita A, Conway W, Zorick F, et al. Surgical correction of anatomic abnormalities of obstructive sleep apnea syndrome: Uvulopalatopharyngoplasty. Otolaryngol Head Neck Surg 1981; 106: 10–13.Google Scholar
  6. 6.
    Powell NB, Riley RW, Guilleminault C. Radiofrequency tongue base reduction in sleep-disordered breathing: A pilot study. Otolaryngol Head Neck Surg 1999; 120: 656–664.Google Scholar
  7. 7.
    Li KK, Powell NB, Riley RW, et al. Radiofrequency volumetric reduction of the palate. Otolaryngol Head Neck Surg 2000a; 122: 410–414.Google Scholar
  8. 8.
    Li KK, Riley RW, Powell NB, Gervacio L, Troell RJ, Guilleminault C. Obstructive sleep apnea surgery: Patient perspective and polysomnogram results. Otolaryngol Head Neck Surg 2000b; 123: 572–575.Google Scholar
  9. 9.
    Pradhan PS, Gliklich RE, Winkelman J. Screening for obstructive sleep apnea in patients presenting for surgery. Laryngoscope 1996; 106: 1393–1397.Google Scholar
  10. 10.
    Simmons FB, Guilleminault C, Miles LE. The palatopharyngoplasty operation for snoring and sleep apnea: An interim report. Otolaryngol Head Neck Surg 1984; 92: 375–380.Google Scholar
  11. 11.
    Johns MW. A new method for measuring daytime sleepiness: The Epworth sleepiness scale. Sleep 1991; 6: 540–545.Google Scholar
  12. 12.
    Parkes JD, Chen SY, Clift SJ, Dahlitz MT, Dunn G. The clinical diagnosis of the narcoleptic syndrome. J Sleep Res 1998; 7: 41–52.Google Scholar
  13. 13.
    Stradling JR, Davies RJO. Is more NCPAP better? Sleep 2000; 23 (Suppl 4): S150–S153.Google Scholar
  14. 14.
    Shumaker SD, Berzon R. The International Assessment of Health-Related Quality-of-Life: Theory, Translation, Measurement and Analysis. Oxford, UK: Rapid Communication, 1995.Google Scholar
  15. 15.
    Johns MW. Sleepiness in different situations measured by the Epworth sleepiness scale. Sleep 1994; 17: 703–710.Google Scholar
  16. 16.
    Bliwise DL, Carskadon MA, Seidel WF, Nekich JC, Dement WC. MSLT-defined sleepiness and neuropsychological test performance do not correlate in the elderly. Neurobiol Aging 1991; 12: 463–468.Google Scholar
  17. 17.
    Folkerts M, Rosenthal L, Roehrs T, et al. The reliability of the diagnostic features in patients with narcolepsy. Biol Psychiat 1996; 40: 208–214.Google Scholar
  18. 18.
    Zwyghuizen-Doorenbos A, Roehrs T, Schaeffer M, Roth T. Test-retest reliability of the MSLT. Sleep 1988; 11: 562–565.Google Scholar
  19. 19.
    Seidel WF, Dement WC. The multiple sleep latency test: Test-retest reliability. Sleep Res 1981; 10: 284.Google Scholar
  20. 20.
    Cronbach LJ. Coefficient alpha and the internal structure of tests. Psychometrika 1951; 16: 297–334.Google Scholar
  21. 21.
    Johns MW. Daytime sleepiness, snoring and obstructive sleep apnea. The Epworth sleepiness scale. Chest 1993; 103: 30–36.Google Scholar
  22. 22.
    Kingshott R, Douglas N, Deary I. Mokken scaling of the Epworth sleepiness scale items in patients with the sleep apnea/hypopnea syndrome. J Sleep Res 1998; 7: 293–294.Google Scholar
  23. 23.
    Liang MG, Fossel AH, Larson ME. Comparisons of five health status instruments for orthopaedic evaluation. Med Care 1990; 28: 632–642.Google Scholar

Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • Ning-Hung Chen
    • 1
  • Murray W. Johns
    • 2
  • Hseuh-Yu Li
    • 3
  • Chia-Chen Chu
    • 4
  • Shu-Cheng Liang
    • 4
  • Yu-Hsiang Shu
    • 5
  • Ming-Lung Chuang
    • 1
  • Pa-Chun Wang
    • 6
    • 7
  1. 1.Department of Pulmonary and Critical Care Medicine, Sleep CenterChang Gung Memorial HospitalAustralia
  2. 2.Sleep Disorders UnitEpworth HospitalMelbourneAustralia
  3. 3.Department of OtolaryngologyChang Gung Memorial Hospital and Chang Gung UniversityTaipeiTaiwan
  4. 4.Department of HealthTaipeiTaiwan
  5. 5.Graduate Institute of Epidemiology, College of Public HealthNational Taiwan UniversityTaipeiTaiwan
  6. 6.Department of OtolaryngologyCathay General HospitalUSA
  7. 7.Department of Public HealthChina Medical CollegeTaichungTaiwan, ROC

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