Multiple Sleep Latency Test (MSLT) is also called a nap study. It is performed for people with excessive daytime sleepiness.

The MSLT can identify narcolepsy, idiopathic hypersomnia (excessive sleepiness without a cause) or whether a normal amount of daytime sleepiness is present.

PROCEDURE :

It is performed during daytime.

Typically this study is  done after an initial overnight polysomnogram (PSG) study.

After waking up, a person  will have scheduled naps at 2 hour intervals during the day.

Generally, they are asked  to lie in bed  for 20 minutes with the goal of falling asleep. A technician will monitor for the onset of sleep , in particular, REM sleep. After 20 minutes, they will be awakened or told that the time for a nap has ended. Then, at  two-hour intervals, this process is repeated 4 or 5 times.  Typically this will take 8 to 10 hours.