Stanford Sleepiness Scale

Questionnaires and rating scales for sleepiness can be divided into two broad categories those that estimate short-term, or moment-to-moment fluctuations, and those that assess more long-term (steady-state, permanent) states. The former is typified by the Stanford Sleepiness Scale (SSS), and is best suited for evaluation of sleepiness/alertness throughout the circadian cycle. The latter are typified by the ESS, and are best suited for the evaluation of sleep disorders. 

The Stanford Sleepiness Scale (SSS) (5) was the most commonly used scale for sleepiness prior to the ESS. It seems to reliably quantify sleepiness in healthy persons (5,6), but its usefulness in sleep disorders is less certain. The SSS consists of seven descriptive phrases that describe the subject s state (see Fig. 1), of which subjects must choose the one that best describes how they feel at the time. Thus,... 

It is important for clinicians and researchers alike to know whether they should rely on objective or subjective measures of sleepiness, or both, and how the two types of measures relate to each other. Since sleep latency on the MSLT is considered the gold standard for objective measure and grading of sleepiness, studies have used this as the objective gold standard. However, not all subjective scales have been studied. Several investigators have reported weak or no association between sleep latency and subjective scales such as the Stanford Sleepiness Scale (26-29). The SWAI, or more specifically its EDS subscale, appears to reli-... 

Herscovitch J, Broughton R. Sensitivity of the Stanford Sleepiness Scale to the effects of cumulative partial sleep deprivation and recovery over sleeping. Sleep 1981 4 83-92. 

Figure 7 PVT reaction times prior to the first uncontrolled sleep attack during total sleep deprivation. Fourteen subjects completed 42 hr of total sleep deprivation and completed a 20-min PVT every 2 hr (represented by the closed circles) 19 subjects completed 88 hr of total sleep deprivation and completed a 10-min PVT every 2 hr (represented by the open circles). The number of test bouts (up to 30) prior to an uncontrolled sleep attack (failure to respond for 30 sec on the PVT) is represented on the bottom abscissa, with time prior to the sleep attack (up to 6 min) represented on the top abscissa. In both subject groups a progressive decline in performance on the visual PVT was evident within minutes of an uncontrolled sleep attack on console. This study also demonstrated an increase in subjective sleepiness (measured using the Stanford Sleepiness Scale) in the test bouts prior to the one in which the first sleep attack occurred. Taken together, these findings suggest that even a very sleepy subject cannot fall asleep while performing computerized tasks without some levels of awareness. (From Ref. 95.)...

Perhaps the most common type of verbal report used in sleep deprivation studies is a measure of subjective sleepiness. Subjective sleepiness is generally assessed by self-report scales (see also Chap. 1), such as the Stanford Sleepiness Scale (19), the Epworth Sleepiness Scale (20), visual analog scales (21), and the vigor and fatigue subscales on the Profile of Mood States (POMS Educational and Industrial Testing Service, San Diego, CA). These measures have been used in studies on the effects of sleep deprivation (22-25), shift work (26-28), and sleep disorders (29,30). 

Glenville M, Broughton R. Reliability of the Stanford Sleepiness Scale compared to short duration performance tests and the Wilkinson Auditory Vigilance task. In Passouant P, Oswald I, eds. Pharmacology of the States of Alertness. Oxford Pergamon, 1979 235-244. 

Kamimori et al. (129) tested the effects of approximately 150, 300, and 600 mg caffeine on noradrenaline and adrenaline levels, sleep latency, Stanford Sleepiness Scale ratings, and choice reaction time in volunteers who were dosed after 49 hr of continuous wakefulness (and kept awake for an additional 12 hr). 

Each study employed a variety of related assessments. In the dextroamphetamine and triazolam studies, flight performance was objectively measured by eomputer in a UH-60 helicopter simulator or aircraft while subjects flew a standardized course central nervous system (CNS) function was measured ly a resting eyes-open/eyes-closed electroencephalograph (EEG) mood and/or sleepiness were measured by self-report instruments such as the Profile of Mood States (POMS) or the Stanford Sleepiness Scale and vigilance and cognition were measured with the Walter Reed Performance Assessment Battery (PAB), the Synthetic Work Battery (SYNWORK), or the Multi-Attribute Task Battery (MATE). 

Newman and Broughton (1991) evaluated differences in pupillary activity between 10 narcoleptics and matched controls. No differences were obtained for pupil diameter under baseline conditions. Pupillary light reflexes and the pupillary orienting responses also failed to discriminate the groups. Narcoleptics, however, demonstrated significantly more spontaneous fluctuations in the dark than normals. Furthermore, Stanford Sleepiness Scale scores did not correlate with pupillary oscillations for either the control or the narcoleptic subjects. 

Other frequently used subjective measures of fatigue are sleepiness scales such as the Stanford Sleepiness Scale (SSS - Hoddes et al., 1972), the Epworth Sleepiness Scale (ESS - Johns,... 

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