How much sleep is needed for an overnight sleep test?

I'm going to be having an overnight sleep lab test and an MSLT the next day. A worker at the sleep lab told me that I would need to get six hours of sleep during the overnight test, in order for it to be valid. Is that because I'm having an MSLT the next day? Or do they generally want a person to get six hours of sleep during the overnight test? Cause my sleep doctor had told me previously that if a person gets about four hours of sleep during the overnight test, that they would have enough data to have a scoreable test.

The sleep tech at the lab I went to said they can get what they need in as little as 2 hours of sleep, but more is better for them to see you sleep in a variety of positions and cycling through a number of sleep cycles. A typical sleep cycle lasts from 90 to 120 minutes where you will go through the various stages of sleep. I managed to sleep about 5 hours at the initial study and about 4 at the titration study.

I'd suggest that on the day of the night you will go to the lab you refrain from coffee and other stimulants, don't take any naps, and get yourself in a frame of mind that this is a test that is important for you to get the answers to your medical issues. Tell yourself it is OK to be wired up, you WILL fall asleep, and this is imperative to your well being to do successfully!

Are you sure they said you have to SLEEP for six hours? At my sleep center, you have to STAY for six hours in order for insurance to pay for it. I can't get all wired up and bail after two hours, or I would end up paying for it out of pocket and they might not be able to score the test depending on how long I stayed.

Protocols are different at some centers but the usual is that you have to have at least two hours of sleep to qualify for a split-night study where they titrate you for a machine the same night, and some of that has to be at least stage 3. There are exceptions to everything, though. In spite of never getting past stage 2 sleep during my diagnostic test, I was diagnosed as extremely severe, and it was estimated I had not had stage 3/4 sleep for months given the way I presented my symptoms. The tech wanted so badly to slap a mask on my face, but their protocol wouldn't allow it since I never got past stage 2.

2 hours of sleep minimum during a split night (less if after 2 hours of bedtime respiratory events are so frequent that they prevent sleep progression and if averaged by 2 hours the AHI is >15), 6 hours of bedtime for a full diagnostic (medicare guideline). Sleep time and bedtime are not the same. These are the general guidlines.

I was really concerned because I only slept 42 minutes the night of my CPAP titration. I was told that Medicare (my primary) required a minimum of 2 hours sleep out of 6 hours bed time so I was brought back in for a second night of titration. I only slept 98 minutes out of 6 hours bedtime. *sigh* But 42 and 98 barely made the required the 120 minutes of sleep for me to qualify for reimbursement for CPAP and accessories. *whew!*

I do think tho, that for the MSLT you would have to have a minimum number of hours of sleep to qualify for reimbursement for the MSLT and for the reliability and viability of the MSLT data.

A google search on MSLT should bring up the requirements.

BigDaddy!!!! Wow, haven't seen you around in quite a while! You beat me to the Submit!

Mine said "6 hours of record time". I'd pay for 6 straight hours of sleep.

Thanks everyone for the replies. I did want to clarify that I haven't been diagnosed with sleep apnea and I'm not using a CPAP. My overnight sleep study is this Tuesday night, followed by an MSLT the next day. Like Slinky had mentioned, I believe that six hours of sleep is needed during the overnight test in order to get a reliable result from the MSLT the next day. Otherwise, if a person didn't sleep well during the overnight test, and then they fell asleep quickly during some of their naps, I guess they wouldn't be able to tell if that was because the person didn't get much sleep the night before, or whether it was from EDS? I'm a little confused though, cause several years back I had a sleep test at a different sleep lab. And during that test, I slept less than four hours, but they still gave me an MSLT the next day.

I tend to get to bed late and get up late. Recently, I've been trying to change my sleep schedule around to try and make sure that I have a better chance of sleeping well during the overnight sleep test. Though, Thursday night, it took me hours to get to sleep. I got less than five hours sleep, and I figured that would be a good thing in a way, to help me get to sleep earlier last night. Though, last night I was awake in bed for hours again. I'm just really worried that I'm not going to be able to sleep well for this sleep test. If I don't get the six hours, I won't be able to do the MSLT, and then I'll have to try and schedule another overnight test once again, plus an MSLT. I had read that some people who had trouble sleeping at the sleep lab were offered a sleeping pill. I assume it was a type of pill that wouldn't affect the sleep stages much. I asked my sleep lab if they would do that for me, and they said no. Could I try something such as melatonin, or could they alter the sleep test results too?

Sorry to ramble on here, but I was also curious about sleep tests for people that are on a third shift type of schedule? Would a sleep lab center have them take the 'overnight' test during the daytime then? And if they needed to take an MSLT, would it be switched around to late in the evening?

They based my diagnosis on only 110 minutes of sleep. That is all I slept in the 6 hours that was supposed to be a split night study. They didn't give me a sleep aid either. Then I had to go back for a titration study separately. The doctor wasn't happy with that because I never went into REM sleep in the first sleep study, which is when the most events occur. Because they could already make a diagnosis of moderate sleep apnea based on light sleep, it was sufficient for insurance. He suggested another sleep study, but when I asked him if it would make any difference in treatment -- he said "no". That is all I needed to hear.

I think your doctor ordered the MSLT because he wants to rule out other sleep disorders.
It has to be the day after the overnight study.

beyondtired wrote: Sorry to ramble on here, but I was also curious about sleep tests for people that are on a third shift type of schedule? Would a sleep lab center have them take the 'overnight' test during the daytime then? And if they needed to take an MSLT, would it be switched around to late in the evening?

Ask, our sleep center here does daytime testing! But they wont mention it unless you ask, they only have half the staff durring the day but it was perfect for me as i cannot sleep at night without drugs.

An MSLT measures how quickly one falls asleep and looks for Sleep onset REM (one important indicator of Narcolepsy). It should follow a full night of sleep and should be in the absence of other untreated disruptive sleep disorders. If your sleep is very disrupted or you slept very little then it would be no surprise that you were sleepy the next day and an MSLT would be a waste of time in most circumstances.

Our lab allows an MSLT after 4 or more hours of sleep. My opinion is that this is not enough sleep however one bad night will propbably not cause sleep onset REM for most but will shorten sleep onset. In the old days everyone got MSLT as part of the diagnostic sleep study. Now we only do them if we suspect Narcolepsy.