title: Sleep patterns and school performance of Korean adolescents assessed using a Korean version of the pediatric daytime sleepiness scale.
abstract: OBJECTIVE
  Korean adolescents have severe nighttime sleep deprivation and daytime sleepiness because of their competitive educational environment. However, daytime sleep patterns and sleepiness have never been studied using age-specific methods, such as the pediatric daytime sleepiness scale (PDSS). We surveyed the daytime sleepiness of Korean adolescents using a Korean translation of the PDSS.
  
  
  METHODS
  We distributed the 27-item questionnaire, including the PDSS and questions related to sleep pattern, sleep satisfaction, and emotional state, to 3,370 students in grades 5-12.
  
  
  RESULTS
  The amount of nighttime sleep decreased significantly with increasing age. During weekday nights, 5-6(th) graders slept for 7.95±1.05 h, 7-9(th) graders for 7.57±1.05 h, and 10-12(th) graders for 5.78±1.13 h. However, the total amounts of combined daytime and nighttime sleep during weekdays were somewhat greater, 8.15±1.12 h for 5-6(th) graders, 8.17±1.20 h for 7-9(th) graders, and 6.87±1.40 h for 10-12(th) graders. PDSS scores increased with age, 11.89±5.56 for 5-6(th) graders, 16.57±5.57 for 7-9(th) graders, and 17.71±5.24 for 10-12(th) graders. Higher PDSS scores were positively correlated with poor school performance and emotional instability.
  
  
  CONCLUSIONS
  Korean teenagers sleep to an unusual extent during the day because of nighttime sleep deprivation. This negatively affects school performance and emotional stability. A Korean translation of the PDSS was effective in evaluating the severity of daytime sleepiness and assessing the emotional state and school performance of Korean teenagers.
authors.affiliation: Department of Pediatrics, CHA Bundang Medical Center, CHA University, Seongnam, Korea.
authors.forename: Seonkyeong
authors.initials: S
authors.lastname: Rhie
authors.forename: Sihyoung
authors.initials: S
authors.lastname: Lee
authors.forename: Kyu Young
authors.initials: KY
authors.lastname: Chae