Testing sleepiness and vigilance in the sleep laboratory.

PURPOSE OF REVIEW: Excessive daytime sleepiness (EDS) is common and a potentially devastating public health challenge. EDS has been implicated as a contributing factor to workplace injury, motor vehicle accidents, cardiovascular disease, and impaired quality of life. Subjective self-report measures have failed to sufficiently quantify EDS. The use of objective tools found in sleep laboratories is therefore fundamental in the management of patients with EDS. The purpose of this review is to provide an overview of the current methods used to quantify sleepiness, and to highlight recent advances.

RECENT FINDINGS: The Multiple Sleep Latency Test (MSLT), normally used for the diagnosis of narcolepsy, can be a useful tool in recognizing other forms of sleepiness. The Maintenance of Wakefulness Test (MWT) has also been confirmed as an important test to identify EDS, as well as to provide an indicator of future risk of accidents. Modifications and newer tests have been discussed with potential applications for the future.

SUMMARY: Objective tests such as the MSLT and MWT are useful in the diagnosis and management of patients with EDS. However, the relatively high cost can restrict their overall usefulness in clinical medicine. Newer simple tests are under development.