Development of a Modified Korean Version of the Epworth Sleepiness Scale Reflecting Korean Sociocultural Lifestyle

Seo Yeon Jung, Chul Hyun Cho, Min Kyu Rhee, Leen Kim, Heon Jeong Lee

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Objective The Epworth Sleepiness Scale is a measure used for the diagnosis of sleep disorders including obstructive sleep apnea (OSA) syndrome, insomnia, and narcolepsy. Although a Korean version has been developed (the KESS), Korean lifestyle such as the floor culture and low driving rates has not been considered. We aim to develop and validate a modified KESS (mKESS) that reflects the Korean lifestyle. Methods The sample consisted of 795 healthy participants and 323 OSA patients. The mKESS was developed by modifying several questions to concern the floor culture (questions 1, 2, 6, and 7) and low driving rates (question 8). Feasibility of the modification was tested by comparing the KESS and mKESS using paired samples t-test and by examining internal consistency reliability. Then, mKESS scores of the OSA patients and general participants were compared to test its validity. Results Questions 1, 2, 7, and 8 were significantly different when comparing the performances of the general population on both scales. Especially, the mean scores on question 8 were significantly different in the non-driver group, but not in the driver group. Cronbach’s alpha of the mKESS was relatively higher than that of the KESS. Total mKESS scores of the OSA patients were significantly higher than that of the general population. Conclusion The mKESS is more universally applicable for the clinical evaluation of people that live in Korea. Results support that the mKESS can be administered to measure the average daytime sleep propensity of the Korean population as an alternative to the KESS.

Original languageEnglish
Pages (from-to)687-694
Number of pages8
JournalPsychiatry Investigation
Issue number7
Publication statusPublished - 2018 Jul


  • Epworth sleepiness scale
  • Korean
  • Modification
  • Sociocultural lifestyle

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Biological Psychiatry


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