Excessive Daytime Sleepiness
Excessive daytime sleepiness refers to the inability to stay alert during the major awake period of the day, resulting in falling asleep at inappropriate times. Excessive daytime sleepiness is more likely to occur in monotonous situations when alerting stimuli are absent, and it is associated with increased risk of accidents, such as when operating motor vehicles or other machinery. The severity of sleepiness can be quantified subjectively using scales such as the Epworth Sleepiness Scale (Table 1) or can be measured objectively in the sleep laboratory using the multiple sleep latency test (MSLT) or maintenance of wakefulness test (MWT).2 The MSLT measures the physiologic tendency to fall asleep in quiet situations, and the MWT measures the ability to stay awake in quiet situations.
Table 1. Epworth Sleepiness Scale*
How likely are you to doze off or fall asleep in the following situations, in contrast to feeling just tired? (This refers to your usual way of life in
…show more content…
It can be caused by disorders such as obstructive sleep apnea (OSA), narcolepsy, and idiopathic hypersomnia [1-4]. A previous study showed that the prevalence of EDS was 2.5% in the Japanese general population [5], and another study showed an EDS prevalence of 8.7% in the general population of the United States [6]. Thus, EDS is common worldwide. People who suffer from EDS sleep a lot during the daytime and usually have cognitive and memory problems. In addition, EDS might be associated with impaired health-related quality of life (HRQOL) in patients with OSA [7] and narcolepsy [8-11]. However, there is a lack of data on the relationship between HRQOL and EDS. Briones et al. found that EDS had an important impact on general health and functional status, which they interpreted as reflecting HRQOL, as measured by the Medical Outcomes Study Short Form 36 [12]. Similar results were also obtained in another study