SleepyHead CA results versus sleep study results

[Wildbuc]

Hi folks, I have recently had 2 sleep studies--about a month apart, that showed very few centrals, and in followup my physician made no mention of centrals being a problem. However, using SleepyHead, my CA is rather high, usually around 75% of apneas found. Does anyone have an explanation? Should I bring this to the attention of my doctor that I will see in 2 weeks?

[robysue]

Hi folks, I have recently had 2 sleep studies--about a month apart, that showed very few centrals, and in followup my physician made no mention of centrals being a problem. However, using SleepyHead, my CA is rather high, usually around 75% of apneas found. Does anyone have an explanation? Should I bring this to the attention of my doctor that I will see in 2 weeks?

What's the total AHI look like?

If you're total AHI is (well) below 5.0, and the CAs make up 75% of an already low number, that would mean you don't need to worry about them.

In particular, if you have a few CAs scored by SH when you're going to sleep, waking up, or lying in bed a wake, they're likely not real CAs anyway.

But if your AHI is (well) above 5.0 and the CAs make up 75% of the events and you think you are sleeping soundly every night, then it is worth mentioning them to the sleep doc.

[jnk]

Keep in mind that if your sleep test occurred at a lab/center, the sleep-test process filtered out all the centrals that didn't matter. Your home machine is unable to do that.

That said, if you fail to get good sleep or are at all concerned about reports of centrals, yes, by all means, tell your doc about such concerns. That's why he's paid the medium-sized bucks.

[Wildbuc]

Thanks for the info. I'll discuss this with my doctor soon. My overall AHI is currently varying from around 5.0 to 7.0. I'm trying hard to get it under control by experimenting with pressures and exercising daily. Have lost 10 lbs. thus far.

[pikov22]

Keep in mind that if your sleep test occurred at a lab/center, the sleep-test process filtered out all the centrals that didn't matter. Your home machine is unable to do that.

Would you please explain about CAs that don't matter? Thanks.

[robysue]

Keep in mind that if your sleep test occurred at a lab/center, the sleep-test process filtered out all the centrals that didn't matter. Your home machine is unable to do that.

Would you please explain about CAs that don't matter? Thanks.

On an in-lab PSG a central apnea is only going to be scored when you are clearly asleep according to the EEG. So any pause in your breathing when you are AWAKE is tossed out and NOT scored on a sleep study. And short pauses in breathing when we're awake are actually not uncommon. Many people hold their breath for a few seconds when they are concentrating on something---even something as simple as turning over in bed.

Moreover, it is not uncommon for people---even those without any kind of sleep apnea---to experience a few 10+ second long pauses in breathing during the transition to sleep as the control of breathing is handed off from the somatic (voluntary) nervous system to the autonomic (involuntary) nervous system. And if those pauses do not cause any problems with the transition to real sleep (i.e. you don't arouse because of them) and there's no significant drop in O2, they will not be scored on an in-lab PSG.

But our machines cannot tell when we're awake nor can they distinguish between a normal "transition to sleep pause in breathing" and a true central apnea. Hence our machines can score events as "CAs" that would NOT be scored on an in-lab PSG.

[pikov22]

Thank you. Are there any other events that are "scored" by a xPAP machine that would be discarded in a sleep lab?

[jnk]

Thank you. Are there any other events that are "scored" by a xPAP machine that would be discarded in a sleep lab?

Home machines are very good at getting obstructive apneas right, although even some of those might be scored mixed in a lab/center.

Everything else from a home machine is mostly just trending data based on proprietary definitions that differ from real sleep-study-data definitions.

As I understand it.

[old dude]

Wow. I love this place.

I am truly in awe of the knowledge that abounds here and the willingness to share it.

Thanks more than you know, folks!

[SleepyToo2]

I am absolutely in awe of what JediMark has done with SH. The single best piece, IMHO, is the leak information. Unfortunately, it cannot tell you why your mask was leaking, but it can tell you when you are doing things to fix the leaks. On the other hand, there is one piece of information that is critical to the success of xpap treatment that no software can tell you. That is, how the heck do you feel? There are many reasons for not feeling good, and xpap cannot possibly fix them all. So, if we feel good, then we have got the xpap working well. individual nights should not be used to determine the success or failure of the treatment; we really need a minimum of a week, preferably longer to be able to see the benefits or otherwise of changes we have made to our treatment/sleeping habits.

I have looked at my SH output to try and determine if there is a correlation between CA events and leaks or other events. I have failed to find anything. I have used a oximeter to see if there are desats associated with the CAs. I have failed to find anything. The only thing I can think of is that I stop breathing when I turn or when I have leg movements, and I have yet to find a way of stopping those events. So the bottom line is that because the CA events are relatively infrequent, I choose to ignore them. However, I do monitor them, and if the frequency increases I will be asking my physician for guidance.

[archangle]

First, was your sleep study with CPAP or without?

Second, If you're actually asleep, I have a fair bit of confidence that what the machine calls a CA is a real central. I think they may classify a central as obstructive. However, it will show some kind of apnea.

Third, look in your data and look at the waveform of the "CA" events. How long do they last? Short ones aren't nearly as harmful as long ones.

Forth, don't worry about centrals being more harmful than obstructive. Centrals may be harder to eliminate, but they aren't necessarily more harmful.

[Wildbuc]

Both my sleep studies involved cpap. The first one used a pressure up to 10 and the second one used a higher pressure.

The centrals showed by SH occurred during actual sleep. Analysis indicated they varied from 10 to 20 seconds.

By the way, the reasons given for a second sleep study were: My apnea frequency was highly dependent upon sleep position, with far more apneas occurring when sleeping on my back. Also, the physician noted that the first sleep study used only a limited amount of pressure (10). She wanted more information and recommended the second sleep study.

Gotta go exercise now, thanks for the info.

[robysue]

I have looked at my SH output to try and determine if there is a correlation between CA events and leaks or other events. I have failed to find anything. I have used a oximeter to see if there are desats associated with the CAs. I have failed to find anything.

Not all apneas have associated O2 desats.

The only thing I can think of is that I stop breathing when I turn or [over?] when I have leg movements, and I have yet to find a way of stopping those events.

A lot of people momentarily wake up when turning over in bed and the concentration needed to turn over often results in a breathing pattern that can be scored as a CA on a machine. Many of these "CAs" would be discounted in the lab because the EEG says you are (momentarily) awake..

Leg movements however can be problematic all by themselves when they become excessive enough to disturb the sleep. There are two different sleep disorders that are tied to excessive leg movements: Periodic Limb Movement Disorder and Restless Leg Syndrome. Did any of your sleep tests mention PLMD or RLS?

So the bottom line is that because the CA events are relatively infrequent, I choose to ignore them. However, I do monitor them, and if the frequency increases I will be asking my physician for guidance.

This sounds like a very reasonable plan to me.