Multiple Sleep Latency Test (MSLT) for Narcolepsy
The MSLT is a daytime nap study done the morning after an overnight sleep study; a mean sleep latency of 8 minutes or less with two or more REM-onset naps supports a diagnosis of narcolepsy.
Updated
The multiple sleep latency test (MSLT) is the standard objective test for narcolepsy and idiopathic hypersomnia. It measures how quickly you fall asleep during the day and whether you enter REM sleep unusually fast.