Sleep Disorders Questionnaire

This chapter will review the questionnaires and rating scales available for the evaluation of sleep deprivation and EDS. Other questionnaires used for sleep disorders but not directly related to EDS (e.g., sleep disorders questionnaires, questionnaires for specific symptoms, restless legs, cataplexy) will not be reviewed. 

Other (less specific) scales have also been used as part of the evaluation of EDS. The basic Nordic Sleep Questionnaire (24) is a quantitative measure of subjective sleep complaints not limited to sleepiness. It focuses on events that happen (during sleep or wakefulness), and grades them on a five-point scale from 1 (never) to 5 (almost every day/night). Thus it is best suited for events but not for sleepiness as such. The Sleep Disorders Questionnaire (SDQ) (25) was extracted from another comprehensive questionnaire, the Sleep Questionnaire and Assessment of Wakefulness (SQAW) of Stanford, but is more geared for the diagnosis of specific sleep disorders (e.g., sleep apnea, narcolepsy) than for the evaluation and quantification of EDS. 

Douglass AB, Bomstein R, Nino-Murcia G, Keenan S, Miles L, Zarcone VP Jr, Guilleminault C, Dement WC. The Sleep Disorders Questionnaire. I. Creation and multivariate structure of SDQ. Sleep 1994 17 160-167. 

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 question arises whether the association of sleep duration with mortality hazard could be an artifact of comorbidities, since so many diseases, disorders, and discomforts are associated with disturbed sleep. In our prior analysis of CPSII, we controlled as far as possible for the major risk factor data available from the CPSII questionnaires, to see if such extensive control for comorbidities would eliminate the significant associations of mortality hazard with sleep duration. 

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