MSLT
Also written as: MSLT — Multiple Sleep Latency Test
Standardized daytime sleep study measuring how quickly a patient falls asleep and enters REM sleep during scheduled naps.
Full Definition
The Multiple Sleep Latency Test (MSLT) is a standardized objective assessment of daytime sleepiness that measures sleep tendency in a controlled environment. The test consists of four to five scheduled 20-minute nap opportunities spaced 2 hours apart throughout the day, typically beginning 1.5-3 hours after the patient's usual wake time. The MSLT measures two key parameters: sleep latency (time to fall asleep) and REM latency (time from sleep onset to REM sleep). A mean sleep latency of less than 8 minutes indicates pathological sleepiness, while sleep-onset REM periods in two or more naps may suggest narcolepsy. The test must be preceded by adequate nighttime sleep documentation and follows strict protocols regarding medications, caffeine, and environmental conditions.
Usage
Usage note: Always use all capitals for the acronym.
In Context
- "The MSLT revealed a mean sleep latency of 3.2 minutes with three sleep-onset REM periods." — Narcolepsy evaluation report
- "MSLT testing was scheduled following two weeks of sleep diary documentation." — Sleep clinic procedure note