Patients being evaluated for central disorders of hypersomnolence should have PSG set up at least 30 minutes prior to habitual bedtime to avoid missing a diagnostic SOREMP6 and ensuring sufficient sleep on the PSG.
The MSLT should be performed following an attended PSG that allows at least 8 hours of time in bed with at least 7 hours of total sleep time. The test should not be performed after a night during which PAP pressures were adjusted (split-night or initial PAP titration study).23–25
Any home PAP/non-PAP therapies for sleep-disordered breathing patients should be used during the PSG and considered for use during MSLT naps based on clinical judgement. The therapeutic modality, PAP settings, and/or mask interface should match those used at home.
Electronic devices should be turned off at least 30 minutes before lights out and should not be accessible to the patient after lights out.
The patient’s clothing should be comfortable, appropriate to the environment, and not interfere with the performance of tests. A change in clothing is not required between the PSG and MSLT.
The patient should abstain from caffeine, nicotine, alcohol, marijuana, and other sedating or alerting agents on the day of the test.
The recording montage for the MSLT should, at a minimum, include 3 electroencephalogram recording leads with at least 1 each for frontal (F3-M2 or F4-M1), central (C3-M2 or C4-M1), and occipital (O1-M2 or O2-M1) derivations, left and right eye electrooculograms, mental/submental electromyogram, and electrocardiogram. Other recording devices or sensors used for the PSG are unnecessary and should be removed to promote the patient’s comfort. The use of alternate acceptable montages in the current version of The AASM Manual for the Scoring of Sleep and Associated Events is at the discretion of the sleep clinician.
Audiovisual recordings must be made during the nap trials and be accessible to interpreting clinicians. The patient must be audiovisually monitored throughout the day, but retention of recordings made between nap trials is discretionary.
The MSLT should consist of 5 nap trials. The initial trial should begin 1.5 to 3 hours after termination of the nocturnal recording. Each subsequent trial should begin 2 hours after the start of the prior trial. Only when the results are clearly diagnostic of narcolepsy after 4 naps or unique patient circumstances dictate a 4-nap study should a shorter 4-nap trial test be considered (see the Performance of nap trials section).
Sleep rooms should be dark, quiet, and at a comfortable temperature during testing. Parents/caregivers should be offered an area outside of the room to wait during the nap trials. If necessary, parents/caregivers may be in the room during the nap trials but should be instructed to not interfere with testing or provide any distraction to the patient and remain quiet.
The patient should be lying in bed for all nap trials.
Patient bio-calibrations should be conducted prior to starting each nap trial. Standard instructions include (1) lie quietly with your eyes open for 30 seconds, (2) close both eyes for 30 seconds, (3) without moving your head, look to the right, then left, then right, then left, right and then left, (4) blink eyes slowly 5 times, and (5) clench or grit your teeth tightly together. Instructions should be tailored to the developmental age of the patient. For example 5, “bite down on your teeth” or “pretend like you’re chewing gum.”
At the start of each nap trial, the patient should be instructed as follows: “Please lie quietly, assume a comfortable position, keep your eyes closed, and allow yourself to fall asleep.” Testing starts immediately after instructions are given and bedroom lights are turned off.
Each nap trial ends if the patient does not fall asleep in 20 minutes. If sleep onset occurs, the trial is continued for an additional 15 minutes, regardless of the amount of intervening sleep or wake. Sleep onset is defined as the start of the first epoch scored as any stage of sleep.6
Vigorous physical activity and prolonged exposure to sunlight/bright artificial light should be avoided all day.
Between nap trials, the patient should be out of bed and not permitted to sleep. Parents/caregivers should participate in keeping the patient awake between the nap trials.
A light breakfast at least 1 hour prior to the first trial and a light lunch immediately after the termination of the second nap trial is recommended.
Urine drug screening should be employed when indicated to ensure that the MSLT results are not confounded by inadvertent, intentional, or illicit medication or substance use (see Appendix C (880.9KB, pdf) ).
