Quantification of Sleepiness: A New Approach

TLDR

The Stanford Sleepiness Scale (SSS) is a self‑rating scale used to quantify progressive steps in sleepiness. The study examined whether the SSS correlates with mental task performance and tracks changes in sleepiness induced by sleep loss. Five college students completed memory and Wilkinson tests in two sessions each, with SSS ratings every 15 min during waking activities, and on night 4 they underwent total sleep deprivation while on other nights they had 8 h in bed. SSS ratings correlated r = .68 with Wilkinson test performance, r = .47 with memory test performance, and baseline SSS scores were significantly lower than during deprivation.

Abstract

ABSTRACT The Stanford Sleepiness Scale (SSS) is a self‐rating scale which is used to quantify progressive steps in sleepiness. The present study investigated whether the SSS cross‐validates with performance on mental tasks and whether the SSS demonstrates changes in sleepiness with sleep loss. Five college student S s were given a brief test of memory and the Wilkinson Addition Test in 2 test sessions and The Wilkinson Vigilance Test in 2 other sessions spaced throughout a 16‐hr day for 6 days. S s made SSS ratings every 15 min during their waking activities. On night 4, S s underwent all night sleep deprivation. On all other nights, S s were allowed only 8 hrs in bed. Mean SSS ratings correlated r = .68 with performance on the Wilkinson Tests. Discrete SSS ratings correlated r = .47 with performance on the memory test. Moreover, mean baseline SSS ratings were found to be significantly lower than corresponding ratings of the deprivation period.