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What In Overnight Study Would Cancel Need For Mslt?


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#1 hbananas

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Posted 05 September 2013 - 07:28 PM

Hello. I am scheduled for an overnight sleep study next week, followed by the mslt.  I got a call from the sleep lab today, and I was told that the mslt is a possibility, not a certainty.  It depends on what the overnight shows.

 

I have been using CPAP for almost 5 years.  I started because of excessive daytime sleepiness.  My pressure prescription hasn't been changed, which is why we're sort of starting over.  I have always had a problem with falling asleep.  Work is the worst place.  It seems the harder the brain has to work, the more likely it is to check out on me.

 

Over the last year or so, the daytime nodding off has gotten worse again, which is why I'm getting the mslt, too.

 

My question is, what would the techs see in the overnight that would cause them to decide the mslt isn't necessary?  If I get bad sleep at my current pressure and it gets better with a change?  If I take a really long time to go into REM?  I'm just wondering.  If we don't do the mslt, I get a day off work to do nothing.

 

I don't have cataplexy, and if I have hallucinated, I'm not aware of it.  When I nod off, I seem to dream right away, because I'll wake up and think how silly the things I was just thinking or dreaming about are in connection with the task I was trying to do at the time.  Maybe that's a hallucination.  Or a daydream that followed me into my little mini-nap.



#2 Livi

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Posted 05 September 2013 - 08:11 PM

If you've been using a CPAP for 5 years, then your overnight will be another CPAP titration?  Or a regular PSG without the CPAP?  If your CPAP pressure prescription needs to be changed, then they'll probably want to see if your sleepiness gets better from making the change in your CPAP.    If there is no change in your sleepiness after one or two or however many CPAP calibrations, they'll probably schedule an MSLT.  Just my guess!   I'm not saying it would be the right decision for you, but sometimes sleep centers have to do things a certain way before a different study will be approved by insurance. 

If it took you a long time to go into REM during the overnight, it doesn't mean anything regarding what your results might be on the MSLT.  I didn't fall asleep for an hour on my PSG and went into REM after another hour (techs kept interrupting my sleep), but the next day went into SOREM three times.  The polysomnogram results will never cancel an MSLT  -  a polysomnogram would tell them that you DO need an MSLT, depending on how bad your EDS is (Epworth Sleepiness) compared to your level of sleep disturbance on the PSG.  For example, a low level of sleep apnea on the PSG with a described high level of EDS would indicate the need for an MSLT.  A high level of sleep apnea on the PSG would not negate the need for an MSLT, but they might want to get you fitted and titrated with a CPAP first to see if that helps eliminate the EDS.  In your case, already having a CPAP that needs to be re-titrated might eliminate the need for an MSLT for now, until they detemine whether your EDS has improved or not.



#3 hbananas

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Posted 05 September 2013 - 08:29 PM

Yes, I believe they will be re-titrating my CPAP prescription.



#4 ironhands

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Posted 06 September 2013 - 08:10 AM

Offhand I can think of a few reasons to cancel an MSLT, the first would be if you couldn't fall asleep during the PSG at all, or for less than a couple of hours.  I don't think there'd be much of a point in doing an MSLT without having a "full" nights sleep the night before.

 

For you case in particular however, there couuld be two reasons.  The first would be if your REM latency is normal, or longer.  An MSLT is generally looking for a SHORT REM latency.  If it takes you 60-120 minutes to enter REM, that's actually very normal.  The second reason the might is if they see your pressures are way off.  It's not uncommon for people to lose a lot of weight when going on CPAP, and require a pressure change to compensate.  If they notice poor sleep, and then change your pressure and notice improvement, they may take that as a sign that everything's okay and send you home.

 

If you want an MSLT, you can have mine, I'm really not looking forward to it :P



#5 Livi

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Posted 06 September 2013 - 12:51 PM

Sorry Ironhands, but I had a very long REM onset in my PSG and it doesn't mean *** for the MSLT.   And actually, it takes about 2-3 weeks for an actual analysis of a PSG by an M.D., which can't officially be done by the techs watching your EEGs.    the techs are not supposed to have the authority to cancel an MSLT that was ordered by an M.D. without a proper analysis of the PSG by the M.D.  

Secondly, hbananas is doing a CPAP titration, not a normal PSG.  



#6 ironhands

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Posted 06 September 2013 - 01:45 PM

It does if there's no prior diagnosis of N.  Having a diagnosis of N will always mean an MSLT will be done.  Without one, and given the EDS could very likely be caused by the CPAP pressures needing to be adjusted, an MSLT may just not be needed and be a waste of a test, especially as the OP hasn't experienced cataplexy or obvious HH.

 

If there are no recorded SOREMs on any tests prior, and the REM latency is normal during the PSG, I can't see there being much point in conducting an MSLT, it would be a wasted test and I don't think most insurance companies would be down with that.

 

The techs often make calls like that, especially when CPAP is involved, the most common being the split study where halfway through the night they begin a CPAP titration.  The only difference in my understanding between a titration study and a standard PSG, is the addition of a CPAP machine.  All of the regular tests are conducted.  The tech can instantly see the REM latency, it's not something that needs to be interpretted, and even if it does, the doctor's probably in early enough to glance at it and say "yup, keep him here".  It doesn't take 2-3 weeks to interpret a PSG because they're especially challenging :P



#7 Livi

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Posted 06 September 2013 - 01:52 PM

The diagnostic criteria for narcolepsy are at least 2 SOREMS on the MSLT.   That means that up to 3 naps do not have to be SOREMS.  Therefore, if the PSG shows a lack of a SOREM, it can be equivalent to the naps on the MSLT that did not have SOREMS.  A late REM on the PSG does not negate the possibility of SOREMS during other sleep opportunities.  Therefore, there would be a reason for conducting the MSLT.

 

Yes, when CPAP is involved, maybe the techs can make the call, but on a regular PSG they are not allowed to.



#8 Livi

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Posted 06 September 2013 - 02:04 PM

Hbananas, on another note, is there a possibility that you misunderstood what the person at the sleep lab was saying?  They might have meant that you need an overnight right now, and then the possibility of another overnight & MSLT at a later date.

 

You might not need ANOTHER overnight & MSLT after the first overnight.   I think that is what they might have meant.   It still doesn't make sense to me that the techs would be allowed to analyze the overnight study so quickly without an M.D. present.  Even if an M.D. is present, it normally takes a while to analyze it since a sleep lab normally has a number of patients.

 

I also don't think they would conduct an MSLT the day after a CPAP titration.   



#9 ironhands

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Posted 06 September 2013 - 02:06 PM

I didn't say that it wouldn't negate the possiblity.

 

I said that if there's no history of it, no prior diagnosis, AND, the PSG shows regular REM latency, they would be unlikely to push it towards an MSLT.

 

Why would they bother to do one if there were no immediate symptoms that couldn't be explained by ineffective CPAP pressure?



#10 Livi

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Posted 06 September 2013 - 02:42 PM

Because maybe I misread, but Hbananas is asking why the overnight study would CANCEL the need for an MSLT.  She's not asking why an MSLT might not be needed.  The fact that she's asking about a possible cancellation means that the doctor thought it was necessary in the first place.  

The only possible reason could be the CPAP titration result.   

 

I had only disagreed with your 2nd paragraph above:   

 

"If there are no recorded SOREMs on any tests prior, and the REM latency is normal during the PSG, I can't see there being much point in conducting an MSLT, it would be a wasted test and I don't think most insurance companies would be down with that."

 

Maybe Hbananas didn't have any prior MSLTs.  If the REM latency is normal during a prior PSG, that doesn't mean anything.  

 

You said:

 

"I said that if there's no history of it, no prior diagnosis, AND, the PSG shows regular REM latency, they would be unlikely to push it towards an MSLT."

 

Everybody starts out with "no history of SOREMS" .  Everybody has a first time being tested based on their subjective description of their EDS.  Of course everybody has a PSG first, before another PSG/MSLT is scheduled.  But if that first PSG doesn't show a SOREM, it doesn't mean an MSLT should be definitively cancelled.  However, if the first PSG shows a high level of sleep apnea, then the CPAP titration takes precedence.  I think we both agree on that.

 

If Hbananas has extreme EDS and possible other symptoms of N, then there would be a need for the MSLT  except if the CPAP titration needs to be modified.

 

And actually, the techs at my sleep center were not allowed to tell me the results of my testing.  They said only the doctor can do that, and it's pretty safe to say that the doctor is not staying there overnight!  



#11 ironhands

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Posted 06 September 2013 - 03:05 PM

The OP may not have had any previous MLST, but there would have likely been an initial PSG, which could have noted a SOREM if there was.

 

An MSLT might be cancelled, if there is no need to do one because there were no events during the PSG that would indicate a need for one. 

 

You're right, everyone starts with no history of SOREMs, but we don't ship everyone off to an MSLT right away as a result.  They didn't send me for an MSLT for this very reason, despite me needing one.  It doesn't indicate anything one way or another, but an insurance company isn't going to pay for that test without more clinical evidence of the need for one, especially with an existing diagnosis of OSA.  One of these could be a SOREM on a PSG.  It isn't cost effective to do 2 PSGs, one including an MSLT.  It is much cheaper, and easier, to watch the initial PSG and based on the rough numbers whether or not it should be continued as an MLST, much the same way as they conduct a split study when they diagnose sleep apnea halfway through the night.

 

The OP doesn't have any other symptoms of N other than EDS which is explained by the apnea, so there wouldn't need to be an MSLT UNLESS there was a recorded SOREM during the PSG that night.  Even if there was it could be explained by poor sleep in the weeks leading up to the titration study. 

 

Really likely depends on the lab, and the insurance carriers, but, as the OP asked, why wouldn't they continue with an MSLT the next morning? 

 

Because they concluded in the night that the EDS was caused by the CPAP needing adjustment, and saw no signs of anythign else.

 

Because they were unable to get enough data to properly calibrate your body for the MSLT (lack of sleep the night before).



#12 Livi

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Posted 06 September 2013 - 03:13 PM

You obviously don't get it that no SOREMS on the PSG don't mean anything, no matter how many times I say it.

 

As far as insurance is concerned, maybe Canada works differently than the U.S. but if the doctor's office says something is necessary, the insurance companies here comply.  At least mine does.

And the only way to do it here in the U.S. is to have 2 PSGs, one of them including the MSLT, and a split study is not used for this purpose.

 

 

The thing that indicates a need for an MSLT is the PATIENT'S EXPERIENCE, not what happens on the PSG!!!  

The PSG is only to diagnose sleep apnea, restless legs, insomnia, other things that are not narcolepsy!!!  If those things don't explain the PATIENT's EXPERIENCE of EDS, then an MSLT should be done!  

 

We DO ship everyone off to an MSLT if there is no significant sleep apnea or significant change in a CPAP titration that accounts for the PATIENT's EXPERIENCE of EDS!  

 

 

We AGREE that if the CPAP needs adjustments, then an MSLT should be cancelled for the time being, so I don't know why you continue this argument.  

 

 

I've made my point and I think my point makes enough sense.  I think Hbanana gets the picture. 



#13 ironhands

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Posted 06 September 2013 - 03:16 PM

Quoted from http://www.sleepmedi...epStudy/MSLTMWT

 

 

CANCELLATION POLICY FOR MSLT

If you have been told that you can go home prior to completion of the study between 3pm to 5pm, this is due to data collected prior. The technician cannot inform you of the specifics of the cancellation. This information will be disclosed in full once all of the data has been collected and reviewed. However, some examples of why the MSLT is cancelled:

  • Insufficient total sleep time noted during the sleep study.
  • Sleep apnea noted during the night-time sleep study.
  • Sufficient data is obtained to allow an accurate diagnosis to end the test early

and from http://www.askmedica...ep-study--72432

 

If on the polysomnogram (the overnight sleep study) they had detected some abnormalities like obstructive or central apneas or if they had come across restless legs syndrome they might have opted to not have the MSLT done. This is because the above mentioned disorders can cause daytime sleepiness.



#14 Livi

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Posted 06 September 2013 - 03:30 PM

Going home prior to the completion of the study is referring to the MSLT.  They can tell you to go home early if you didn't have REMs on the first 4 naps, because 2 SOREMs are needed and there are 5 naps total.  

 

I agree regarding their points for canceling an MSLT in the FUTURE (in which case it's not being "cancelled", it's just not being scheduled), not the day after the PSG, in which there is not enough time for an accurate analysis or there is no M.D. present.  

 

The rest is what we agree on, if there is significant sleep apnea for which a CPAP may account for the sleepiness and the techs are able to determine this without an M.D. present.  At least here in the U.S. it has to be done according to protocol, meaning analysis by an M.D. no matter how obvious the results are to a tech.

 

No more arguing for me!   We can totally agree to disagree and that's fine by me!



#15 ironhands

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Posted 06 September 2013 - 04:01 PM

No, it's referring to the entire process. It's just poorly formatted.

 

They wouldn't do half an MSLT if any of those points were true.  If they see RLS, OSA, CSA, an MLST wouldn't be be necessary.  The only reason it *might* be necessary, is if there is a previous diagnosis of N, or more symptoms such as C or HH, OR, if a SOREM appeared on the PSG. 

 

This is why the lack of a SOREM matters on the PSG.  Just like you can have N without C, you can have N without a SOREM on a PSG.  If there are no symptoms or red flags, the way a SOREM on the PSG would be, there wouldn't be much point in wasting the additional time and money on an additional test, and the doctor agreed which is why the doctor informed the OP that it may be cut short or cancelled.  It has nothing to do with the differences between Canadian medical insurance and privatized, the doctor hasn't conlcuded that the MSLT is 100% necessary.

 

You are right, an MSLT is done when the PSG reveals a condition contributing to the EDS.  This is exactly why they would cancel the MSLT.



#16 hbananas

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Posted 06 September 2013 - 07:23 PM

Wow.  I had no idea this would generate so much discussion.  Here are some facts:

I have had excessive daytime sleepiness all my adult life, beginning in high school.

My OSA was discovered with a sleep study to rule out other causes for my sleepiness (specifically multiple sclerosis, because I have had an attack of transverse myelitis and some nonspecific brain lesions.)  I didn't have a ton of apneas/hypopneas, but I did have lots of respiratory arousals.

When I got started with CPAP, my AHI was down below 5.

Now, according to the software on my machine it's around 8 or 9 many nights.

My new MS neurologist sent me to the sleep doc because I was again complaining of extreme daytime sleepiness.  Some days I nod off a dozen or fifteen times at my desk.  I have had to give up a hobby I love because I can't stay out late one night a week to work on it, or I pay for the next 3 days.  I had a mini nap while driving alone on a 3 hour trip that included two previous rest breaks/naps.

So, the sleep specialist definitely ordered the PSG to check my pressure, and the MSLT to check the possibility of narcolepsy, even though I don't have the cataplexy or HH symptoms.  Unlike the happy situation suggested by one post, I haven't lost weight on CPAP.  I've gained, making the pressure adjustment probably go in the other direction.

 

So, we shall see.  Thank you all for the useful information.



#17 ironhands

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Posted 06 September 2013 - 09:17 PM

an AHI of 9 would likely be causing some issues for your sleep, it's still considered "mild", but between 5-9 I wouldn't expect a dramatic change in your sleep patterns the way you are describing.  Hopefully they won't send you home, as an MLST would be highly recommended now based on the additional information.  MS, and N are both on the HLA-DQB1 gene along with celiac and diabetes.  I don't think there's a confirmed comorbidity or anything, but in my mind, it would seem there could be a connection between those symptoms.

 

I think only about 70% of PWN have C.  HH can be a little strange, it may happen and you won't recognize it, or may forget it.  I've been having it all my life and assumed it was normal.  If you're sleeping that much during the day, I'd say it's a high probability that there's something going on, hopefully they won't dismiss you as just an apnea case given the previous diagnosis - that's what they did with me, and now I have to redo both the MSLT and PSG, even though I hit a 0.0 AHI on my PSG.  When you meet with the technician/technologist, stress to them that you AHI has only changed a few points, but you're feeling sleepier and sleepier as the weeks progress.

 

As for the weight loss - it's usually a result of being able to use the extra energy you get from getting a proper nights sleep.  However, in some people, the depression lifts and they suddenly find themselves enjoying food a lot more :P

 

Good luck on both tests, let us know how it turns out!

 

Also, cpaptalk.com is a great and very active forum for sleep apnea, lotta good people and info there.



#18 Chemist

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Posted 06 September 2013 - 10:15 PM

When I went in for my sleep study they were very clear: If the overnight polysomnogram shows evidence of sleep apnea, the sleep study will end immediately after the polysomnogram and no MSLT will be performed. However, this is for people who have no pre-existing diagnosis for either narcolepsy or sleep apnea, which was the situation I was in. If someone already has a diagonsis of either sleep apnea and/or narcolepsy, the details probably depend upon the patient's personal situation. If the physician simply wanted to try a CPAP re-titration, then they likely would not have even placed an order for an MSLT. If the physician felt that there was a comorbidity of sleep apnea and narcolepsy, then they could order an MSLT by itself.

 

But hbananas, how it's going to work is this: Just have the sleep study done as it has been ordered. If a re-titration of your CPAP does not help you, make that clear to your phsyician. They will then have no choice but to order an MSLT to check for comorbidity of narcolepsy. I totally sympathize with the fact that it can be a pain in the butt to schedule sleep studies, especially if you have work or other obligations. Sometimes you just have to let them run whatever tests they want to run first, even if they probably won't provide any useful information.

 

Personally I didn't have any SOREM during my polysomnogram, yet I had SOREMS on 3/4 naps and a mean sleep latency time of ~3 minutes during the MSLT that immediately followed. So like was said previously, whether or not you have a SOREM during the PSG says nothing about whether or not you have narcolepsy.



#19 ironhands

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Posted 06 September 2013 - 11:03 PM

 

Personally I didn't have any SOREM during my polysomnogram, yet I had SOREMS on 3/4 naps and a mean sleep latency time of ~3 minutes during the MSLT that immediately followed. So like was said previously, whether or not you have a SOREM during the PSG says nothing about whether or not you have narcolepsy.

 

Nope, it wouldn't, but there'd be no reason to continue through to an MSLT if the symptoms were entirely explained by the apnea events.  The only reason to continue through to the MSLT if apnea was detected would be if there were any of the following: a SOREM on the PSG, C, HH, or a previous diagnosis of N.  There's no point in continuing to test when you've already found the cause, which would appear to be apnea.  Had there not been a SOREM on my PSG, I wouldn't have a diagnosis at this point.  My current situation is the exact opposite as the OP, they didn't schedule me for an MSLT afterwards, when they clearly should have.

 

Based on the OP's original statements, it wouldn't appear that there'd be a need for the MSLT unless a SOREM was detected, since there was no C, HH, sleep paralysis, etc, mentioned.  The only symptom presented was EDS which is easily explained away with apnea.  This is why the lack of a SOREM on the PSG would be important.  That would have been the only symptom that could be measured and observed during the night that would be different from the apnea.

 

Based on the new info the OP has presented, I have little doubt that an MSLT should be performed regardless of any SOREM activity on the PSG, as the EDS sounds pretty severe, especially when the apnea being recorded by the CPAP is mild.  Unless there is another condition that presents itself during the PSG, like RLS, it's likely something more than the PSG could diagnose.  Whether or not it's N is another matter, sounds likely, but it also sounds like there's a lot going on in there.  I'd be really interested in seeing the hypnogram.



#20 hbananas

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Posted 12 September 2013 - 08:41 PM

I had my PSG last night and my MSLT today.  We did all 5 naps.  After #4, I asked the tech how he would decide if #5 was necessary, and he actually told me that 2 REMs would be part of a narcolepsy diagnosis, so I can only surmise I had 1 REM in the first four.

 

He said my PSG at my prescribed pressure is doing its job.  No apneas or hypopneas recorded.  He said they'd call with results when they have them.  It was kind of fun spending the day as the only patient there and getting the royal treatment.  He even went out to Wendy's and got us lunch.