MWT review paper.qxp

EXCESSIVE SLEEPINESS IS DEFINED AS SLEEPINESS OCCURRING IN A SITUATION WHEN AN INDIVIDUAL WOULD BE EXPECTED TO BE AWAKE AND ALERT. It is a chronic problem for about 5% of the general population,1, 2 and it is the most common complaint evaluated by sleep disorder centers.1, 3 The most common causes of sleepiness include partial sleep deprivation, fragmented sleep and medication effects. Sleepiness is also associated with sleep disorders such as sleep apnea4 and narcolepsy5 as well as some medical and psychiatric disorders.6, 7 Excessive sleepiness and impaired alertness during wakefulness have been associated with increased morbidity for the individual and may threaten the safety of others as well.8, 9 The assessment of sleepiness is an important part of the evaluation and management of the sleep disorders patient. Historically, the Multiple Sleep Latency Test (MSLT)10 and the Maintenance of Wakefulness Test (MWT)11 have been the primary objective tests used for the measurement of sleepiness and alertness, respectively. Results of these tests are used to help diagnose sleep disorders, evaluate treatment and to support recommendations to the patient on the advisability of driving or performing other daily activities. The tests have also been recommended by regulatory agencies to support a decision to return a sleep disorders patient to service in a safety-sensitive position after treatment. This decision, and the measurements used to make it, may critically affect both public safety and the career of the patient. Thus, it is extremely important that evidence-based data are examined to determine the usefulness and limitations of these tests. The current review provides an examination of sleep latency data reported in the peer-reviewed literature. Guidelines for the use of the MSLT were initially established in 1992 based on consensus.12 Since then, the body of scientific literature using the MSLT and MWT has grown substantially. Consequently, this review was requested by the Standards of Practice Committee of the American Academy of Sleep Medicine (AASM). All authors completed AASM conflict of interest statements and were not found to have any significant conflicts with regard to the topics discussed in this review. The objectives of this paper are to review unique issues related to measuring sleepiness and to assess the database of evidence for the clinical use of the MSLT and MWT.