[Multiple sleep latency test, maintenance of wakefulness test and suggestive immobilization test]

In clinical practice, assessment usually involves self-report; however, objective measures are available. The multiple sleep latency test(MSLT) is performed during the main period of wakefulness and is designed to determine a patient's propensity to fall asleep. To be valid, the MSLT should be performed the day after nocturnal polysomnography (PSG). It is the standard test for the assessment of objective sleepiness and diagnosis of narcolepsy, that is a mean sleep latency equal to or under 8 minutes and equal to or greater than two sleep onset REM periods (SOREMPs). As opposed to the MSLT, the maintenance of wakefulness test (MWT) is designed to test the patient's ability to stay awake. The MWT is a 40-minutes protocol consisting of four trials separated by 2-hour intervals and is performed in much the same way as the MSLT. The MWT may be indicated in assessment of individuals in whom the inability to remain awake constitutes a safety issue, or in patients with narcolepsy or idiopathic hypersomnia to assess response to treatment with medications. There is little evidence linking mean sleep latency on the MWT with risk of accidents in real world circumstances. The suggestive immobilization test(SIT) was designed during which sensor and motor symptoms of restless legs syndrome are quantified during a period of immobility taking place in the evening before PSG. The patient is instructed to avoid moving voluntary for the entire duration of the test, which is designed to last 1 hour. The subjective leg discomfort evaluation and periodic leg movement by surface electromyograms from right and left anterior tibialis support diagnosis for restless legs syndrome. Many factors, such as clinical setting, pretest condition or aging effects etc. can alter the findings of the test and considerable clinical judgment is needed to avoid an error in interpretation. Above those three sleep-wake related tests provide us useful information.