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Sleep. 2004 May 1;27(3):541-8.

A pictorial sleepiness scale based on cartoon faces.

Author information

1
Wits Dial-A-Bed Sleep Laboratory, Brain Function Research Unit, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa. sleep@physiology.wits.ac.za

Abstract

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.

PMID:
15164912
DOI:
10.1093/sleep/27.3.541
[Indexed for MEDLINE]

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