What is an MSLT?
The Multiple Sleep Latency Test (MSLT) is a daytime sleep test used to measure how quickly a person falls asleep in a quiet setting and whether REM sleep appears unusually early.
Diagnostic testing
MSLT Test for Narcolepsy
What an MSLT is, why it is used in narcolepsy assessment, how it follows an overnight sleep study and how to prepare for reliable results.
Medical information reviewed in the context of the Sleep Lab by Dr Omar Laraqui Hossini. This page is educational and does not replace an individual medical assessment.
Why it is used
The MSLT can provide objective information when a sleep specialist is investigating narcolepsy or another central disorder of hypersomnolence. Results are interpreted together with symptoms and the overnight sleep study.
Usually performed after polysomnography
An overnight polysomnography is generally performed before the MSLT. This helps document the preceding night of sleep and identify factors that could make the daytime test difficult to interpret.
Preparation matters
Sleep schedule, insufficient sleep, shift work and some medicines can affect MSLT results. Patients should follow the laboratory instructions and discuss medicines with the prescribing clinician rather than changing treatment on their own.
Next step
Discuss your symptoms with a sleep specialist.
If you are concerned about narcolepsy, hypersomnia or persistent daytime sleepiness, you can begin with an online consultation. Testing in Casablanca is arranged only when clinically indicated.
Request an appointment
For emergencies or urgent symptoms, contact local emergency or medical services rather than using the online appointment form.