Frequently asked questions

What is an MSLT and how does it work?


When you have an MSLT, first you have an Overnight Sleep Study followed immediately the next morning by the daytime MSLT. You will arrive at the sleep center in the evening for your Overnight Sleep Study and remain at the sleep center until 5pm the next day for the MSLT. You will spend up to 20 hours at the sleep center for the Overnight Sleep Study followed by the MSLT. First you will have the Overnight Sleep Study, ending about 6 am. You will stay at the sleep center and then start the MSLT about 8 am continuing to about 5 pm. The MSLT is a test designed to measure how sleepy you are. Generally, physicians use the MSLT to rule out narcolepsy and help identify the cause of daytime sleepiness. The test is a series of naps where we measure how long it takes you to fall asleep. MSLT stands for Multiple Sleep Latency Test. “Multiple” means there are multiple naps. “Sleep Latency” is how long it takes you to fall asleep. The test has a series of up to 5 short naps throughout the day.




Do I spend the night for the overnight sleep study, then the whole next day for the MSLT?


Yes. When you have an MSLT, first you have an Overnight Sleep Study followed immediately the next morning by the daytime MSLT. The Overnight Sleep Study will start between 9 pm and 10:30 pm and will continue to about 6 am the following morning. The MSLT will start immediately following the sleep study, usually beginning at 8 am and continuing until 5 pm. In some limited cases, the MSLT may finish as early as 3 pm.




What do I wear to my MSLT test?


Be comfortable. Two-piece pajamas (separate top & bottom). Undergarments do not qualify as pajamas (such as men’s boxers) and shorts or sleeping pants must be worn. Even though you may have a favorite night gown or prefer to sleep au naturel, two-piece pajamas are a must for the comfort of the technician performing your study and the need to attach electrodes and leads in various positions (around your waist and legs, etc.). Here are some examples of appropriate, two-piece pajamas to wear to a sleep study:




What about food and entertainment during the day?


Please bring food with you for your MSLT or arrange to have it delivered to you. We do not provide food during the MSLT test. We suggest you pack a cooler with sandwiches or other food and bring it with you. You can also have someone drop food off for you or have food delivered. Please avoid caffeine the day before the Overnight Sleep Study and the day of the MSLT. For entertainment, we provide free wi-fi and cable TV. You are welcome to bring a wi-fi capable device.




Can I take a sleeping aid or a sleeping pill  before my sleep test?


Our goal is to watch you sleep so that we can evaluate you for a sleep disorder. When a patient is unable to fall asleep during the evaluation, it precludes our ability to monitor their sleeping patterns. It is common for some patients to take sleeping pills to help achieve the goals of the study. Points to consider before taking a sleeping aid before your sleep study: Continue to take any prescribed medications that you usually take (unless otherwise instructed by your doctor). If you usually take a medication at night, bring it with you to the sleep center. List all medication, prescribed or over-the-counter (including any sleep aids), that you have taken, on your medication list in your intake paperwork. We don’t know what effect the sleep aid may have on you, so please arrange for safe transportation home from the sleep center in the morning. Generally, sleep aids have little or no effect on the diagnosis’s made from your sleep study data, but the reasons for having the sleep study need to be considered. If you are having the sleep study to evaluate sleep disordered breathing, like obstructive sleep apnea, the sleep aid shouldn’t have any effect on your normal breathing patterns. Sleep aids may change your sleep architecture like reducing the latency to sleep onset, altering the depth of sleep, changing the percentage of time spent in some sleep stages and increasing your total sleep time or sleep efficiency which could impact your diagnosis for other sleep disorders like insomnia. It’s best to talk to your doctor if you have any concerns. Most importantly, please make sure that you include the sleep aid, if you decide to take it, on your medications list.