Name of questionnaire | Stanford Sleepiness Scale (SSS) |
Type of questionnaire-description | Self-rating scale which evaluates sleepiness at a certain point in time. Respondents select one of seven statements best representing their perceived sleepiness |
Number of items | 1 |
Number of domains/categories | 1 |
Name of categories/domains | Degree of sleepiness |
Scaling of items | Seven –point Likert-type scale has descriptors ranging from “feeling active, vital alert, or wide awake” (score = 1) to “no longer fighting sleep, sleep onset soon and having dream-like thoughts” (score = 7) |
Scoring available: with permission or free | Free |
Scoring test-retest reliability | 0.88 |
Scoring Internal consistency | Not available |
Validity | Validity of mean SSS using the Wilkinson addition and vigilance tests was reported at correlation of 0.68 |
Language | English |
Patient populations in whom questionnaire has been validated | Adults |
Translations in other languages (if yes, then list the languages) | Not applicable |
Developer name | E. Hoddes, V. Zarcone, H. Smythe, R. Phillips, W. C. Dement |
Developer contact information | William C. Dement, M.D., Ph.D. Professor of Psychiatry and Sleep Medicine Department of Psychiatry and Behavioral Sciences Stanford University School of Medicine 1050A Arastradero Rd. Palo Alto, CA 94304 Ph: 650-723-6320 Fax: 650-723-8134 |
Availability of questionnaire: | Freely available |
Limitations | Questionable reliability in chronic sleep deprivation, cumulative partial sleep deprivation and narcoleptics |
Link to the questionnaire (if available) |
https://aurora.edu/documents/wellness/toolbox/alertness-test.pdf |
Other comments | It can be administered many times per day which is useful over the course of a study (e.g., treatment intervention). Correlates with standard measures of performance and reflects the effects of sleep loss. |
References |
Original publication:
Validity and reliability in different populations:
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Updated by |
Marie-Anne Melone |
Last update | September 2022 |