title: Modification of the Epworth Sleepiness Scale in Central China.
abstract: OBJECTIVE
  The well-known excessive daytime sleepiness (EDS) assessment, Epworth Sleepiness Scale (ESS), is not consistently qualified for patients with diverse living habits. This study is aimed to build a modified ESS (mESS) and then to verify its feasibility in the assessment of EDS for patients with suspected sleep-disordered breathing (SDB) in central China.
  
  
  METHODS
  A Ten-item Sleepiness Questionnaire (10-ISQ) was built by adding two backup items to the original ESS. Then the 10-ISQ was administered to 122 patients in central China with suspected SDB [among them, 119 cases met the minimal diagnostic criteria for obstructive sleep apnea by sleep study, e.g., apnea and hypopnea index (AHI) ≥ 5 h(-1)] and 117 healthy central Chinese volunteers without SDB. Multivariate exploratory techniques were used for item validation. The unreliable item in the original ESS was replaced by the eligible backup item, thus a modified ESS (mESS) was built, and then verified.
  
  
  RESULTS
  Item 8 proved to be the only unreliable item in central Chinese patients, with the least factor loading on the main factor and the lowest item-total correlation both in the 10-ISQ and in the original ESS, deletion of it would increase the Cronbach's alpha (from 0.86 to 0.87 in the 10-ISQ; from 0.83 to 0.85 in the original ESS). The mESS was subsequently built by replacing item 8 in the original ESS with item 10 in the 10-ISQ. Verification with patients' responses revealed that the mESS was a single-factor questionnaire with good internal consistency (Cronbach's alpha = 0.86). The sum score of the mESS not only correlated with AHI (P < 0.01) but was also able to discriminate the severity of obstructive apnea (P < 0.01). Nasal CPAP treatment for severe OSA reduced the score significantly (P < 0.001). The performance of the mESS was poor in evaluating normal subjects.
  
  
  CONCLUSIONS
  The mESS improves the validity of ESS for our patients. Therefore, it is justified to use it instead of the original one in assessment of EDS for patients with SDB in central China.
authors.affiliation: Department of Respiratory Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, 430022 Wuhan, People's Republic of China. zjnwhhb@163.com
authors.forename: Jin Nong
authors.initials: JN
authors.lastname: Zhang
authors.forename: Bo
authors.initials: B
authors.lastname: Peng
authors.forename: Ting Ting
authors.initials: TT
authors.lastname: Zhao
authors.forename: Min
authors.initials: M
authors.lastname: Xiang
authors.forename: Wei
authors.initials: W
authors.lastname: Fu
authors.forename: Yi
authors.initials: Y
authors.lastname: Peng
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D002681:China; D003466:Cultural Characteristics; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012891:Sleep Apnea Syndromes / Q000150:complications / Q000175:diagnosis*; D011795:Surveys and Questionnaires; D014177:Translations; D055815:Young Adult