Tags: soremps

What is an MSLT?

An MSLT, Multiple Sleep Latency Test, is a nap study. It is used to see how quickly you fall asleep in quiet situations during the day.

The study is based on the idea that you should fall asleep in a shorter amount of time as your feeling of sleepiness increases. The MSLT charts your brain waves, heartbeat, records your eye and chin movements. The study also measures how quickly and how often you enter the rapid-eye-movement (REM) stage of sleep. Results of the nap study are routinely used to detect sleep disorders.

The study isolates you from outside factors that can affect your ability to fall asleep. These factors include such things as the following:

  • Temperature (too hot or too cold)
  • Light
  • Noise
  • Activity

Other factors that can still affect the results of the study include the following:

  • Anxiety
  • Tension
  • Depression
  • Age
  • Caffeine
  • Drugs and medications
  • Amount of sleep prior to the study

The use of stimulants needs to be stopped for two weeks before the MSLT. Your sleep specialist should help you properly schedule the use of any other medications.

An MSLT is used to evaluate people who are thought to have narcolepsy. Most people with narcolepsy fall asleep in average of less than fire minutes during the test. Some take longer than five minutes to fall asleep. There are also people without narcolepsy who fall asleep in less than five minutes. The test also counts sleep-onset REM periods (SOREMPS). This is having REM sleep very soon after you fall asleep. REM sleep is normally the fifth and last stage of each sleep cycle. Having two or more SOREMPS in an MSLT is usually the indicator of narcolepsy.

An MSLT may be used to see if a person has idiopathic hypersomnia. These patients will fall asleep easily but do not have SOREMPS.

An MSLT will reveal a broad range of time in which it takes normal sleepers to fall asleep. Normal sleepers usually fall asleep in an average of about ten minutes during the five naps of the MSLT. Due to the wide range of normal times, the results alone are not enough to diagnose a sleep disorder. Doctors must also consider other data, tests, and medical information.