Stanford Sleepiness Scale (SSS)

  • Azmeh Shahid
  • Kate Wilkinson
  • Shai Marcu
  • Colin M. Shapiro


The SSS is a subjective measure of sleepiness, frequently used for both research and clinical purposes. Whereas an instrument like the Epworth Sleepiness Scale (Chap. 29) examines general experiences of sleepiness over the course of an entire day, the SSS evaluates sleepiness at specific moments in time. Consisting of only one item, the scale requires respondents to select one of seven statements best representing their level of perceived sleepiness [1]. As a single-item measure, the scale is best suited for repeated use over the course of a research study or treatment intervention.


  1. 1.
    Hoddes, E., Dement, W., & Zarcone, V. (1972). The development and use of the Stanford sleepiness scale (SSS). Psychophysiology, 9, 150.Google Scholar
  2. 2.
    Hoddes, E., Zarcone, V., Smythe, H., Phillips, R., & Dement, W.C. (1973). Quantification of sleepiness: a new approach. Psychophysiology, 10, 431–436.PubMedCrossRefGoogle Scholar
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    Broughton, R. (1982). Performance and evoked potential measures of various states of daytime sleepiness. Sleep, 5, S135-S146.PubMedGoogle Scholar
  4. 4.
    MacLean, A. W., Fekken, G. C., Saskin, P., & Knowles, J.B. (1992). Psychometric evaluation of the Stanford sleepiness scale. Journal of Sleep Research, 1(1), 35–39.PubMedCrossRefGoogle Scholar

Representative Studies Using Scale

  1.  .
    Carskadon, M. A. & Dement, W. C. (2007). Cumulative effects of sleep restriction on daytime sleepiness. Psychophysiology, 18(2), 107–113.CrossRefGoogle Scholar
  2.  .
    Connor, J., Norton, R., Ameratunga, S., Robinson, E., Civil, I., Dunn, R., Bailey, J., & Jackson, R. (2002). Driver sleepiness and risk of serious injury to car occupants: population based case control study. British Medical Journal, 324, 1125–1128.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Azmeh Shahid
    • 1
  • Kate Wilkinson
    • 1
  • Shai Marcu
    • 2
  • Colin M. Shapiro
    • 3
  1. 1.University of Toronto The Youthdale Child and Adolescent Sleep CentreTorontoCanada
  2. 2.University of Toronto The Youthdale Child and Adolescent Sleep CentreTorontoCanada
  3. 3.Department of PsychiatryUniversity of Toronto The Youthdale Child and Adolescent Sleep CentreTorontoCanada

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