A pictorial sleepiness scale based on cartoon faces

Sleep. 2004 May 1;27(3):541-8. doi: 10.1093/sleep/27.3.541.


Study objectives: To develop a sleepiness scale devoid of semantic or geometric elements.

Design: Subjects were asked to rank in order 7 cartoon faces representing degrees of sleepiness. We used Thurstone's scaling procedure to transform these rankings into an interval scale, which allowed us to eliminate 2 of the faces. The remaining 5 faces were ranked again using other subjects. In a validation study, subjects rated their perceived level of sleepiness using our scale and other sleepiness scales. Employed shiftworkers and school-going children used our scale to assess its practical applicability.

Settings: Research and diagnostic sleep laboratories, pre-primary to tertiary institutions, shift-working industry.

Participants: Ethnically diverse healthy and sleep-disordered adults (n = 490), and school-going children (n = 345).

Measurements and results: Our faces scale correlated with the Karolinska Sleepiness Scale (P < .05), the Stanford Sleepiness Scale (P < .04), and a visual analog scale measuring sleepiness (P < .0001). Shiftworkers showed a time-on-task effect on the evening shift (P < .0001) and a peak in sleepiness at 4:00 and 5:00 (P < .0001) on the night shift. Eight to 10 year old children appeared sleepier than older children throughout a school day (P < or = .02) and became sleepier as the day progressed (P < .0001). We confirmed that our scale measures sleepiness, uncontaminated by pain, anger, or happiness.

Conclusions: We have devised a sleepiness scale suitable for people too young or insufficiently educated to employ more-conventional scales. We envisage the scale being used for diagnostic, therapeutic, and research purposes.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Cartoons as Topic*
  • Child
  • Child, Preschool
  • Disorders of Excessive Somnolence / diagnosis*
  • Disorders of Excessive Somnolence / epidemiology
  • Face*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Surveys and Questionnaires*
  • Visual Perception*