Sleep Onset Centrals

First time poster, frequent lurker. I have some questions that I hope that the collective genius can answer.

I have heard that it is common for people to experience some central apneas when falling asleep. And as long as long as they are not too many events or over too long a time it's not an issue.
My questions are around what those centrals look like and when to be concerned.

My example: I had a stressful night last week and was awake in bed for a few hours being mentally consumed over a co-worker issue (resolved now) and once I finally fell asleep, the graphs showed about 20 mins of nearly constant centrals. Shown below I looked over my previous 5 months and noticed that I usually have between 5-10 minutes of centrals as I'm falling asleep but only for about 30% of the nights (more so recently). This night was was just especially bad. There was no mention of Centrals in my sleep study report.
Zooming in some more I see that all such centrals appear to be real (I do not recall being awake at that time) and that they are rather rhythmic. This led to some googling and discovery of "cheyne stokes respiration" or CSR. Now after googling "cheyne stokes respiration," It's very easy to assume that you have less than a month to live. Further googling will lead you to find out that "Sleep onset centrals" are also rather common (brain switching breath regulation methods). But that's all I was able to gather and could not link them together.

So my questions are thus:
1. Does this looks like CSR to you? Sleepyhead did not flag it as anything, not even PB, but looks almost textbook. 2. Are most peoples' "sleep onset centrals" also looks like CSR or PB? or something else?
3. At what point should I be worried about CSR showing up? is it only bad if it's in the middle of the night? or some percentage of the night? or only if it's flagged as PB? or should I check out a heart doctor ASAP.
4. Probably useless to ask how to stop these centrals as they seem to be "par for the course", but has anyone had any success? I feel like they are stress or mentally related. And I am assuming that some better "sleep hygiene" would help (ie limit screen time/caffeine, have a routine, read a book, etc.) Alternatively, being tipsy from imbibing spirits seems to prevent this, but that's not what one would consider healthy or sustainable.

Some other background for reference:
Been on CPAP at 11 cmH20 for about 5 months rather successfully (averaging under 5 AHI until recently). I have a PR Dreamstation, nasal pillows, hardly any leaks, heated tube, humidifier at max, flex at 3/3, no ramp. I've also lost 30+ lbs over the last 2.5 months (keto) and not sure how that's affected things (other than snoring is down). I like videogames and audiobooks, am happily married with a 2.5 year old and another on on the way near Chicago, IL.

Thanks in advance.

TL:DR - Does anyone have rhythmic centrals as they fall asleep for 5-20 mins?

Welcome to the forum.

SleepyHead doesn't decide if the breathing looks like PB/CSR....it's the machine that decides and does the flagging if it thinks the criteria is met. So the machine doesn't think that your flow/breathing pattern looks like PB.
PB is Periodic Breathing which is nothing but a waxing and waning of the flow rate and it has to last at least 2 minutes.
CSR is a form of Periodic Breathing but not the only form.
SleepyHead only reports whatever data the machine gathers.

Your breathing pattern with those flagged centrals doesn't look like PB or CSR to me...so I would agree with the machine.

Your breathing immediately prior to the first flagged CA at around 01:55 on the report looks more like awake/arousal breathing than asleep breathing. Hard to say for sure because that segment is so short. So it's kinda hard to try to spot the transition from awake to asleep breathing which is what we would try to figure out if we wanted to try to call these sleep onset centrals.

I don't know if those centrals are real or not. They look real to me but I am not the best at this sort of stuff.

What you might do is reduce the Flex exhale relief setting to 1 or even off and see if it seems to stop whatever this is.
For some people the Flex exhale relief creates a situation sometimes where centrals will happen because too much carbon dioxide gets blown off. Might not happen all the time and we don't know why.

Stress can indeed cause a sort of sleep-initiation insomnia in which we get stuck in a loop while transitioning into sleep. The first stage of sleep is barely sleep, and in between the waking world and the sleeping world lies the tortured state of being neither here nor there. It's like trying to change gears in a standard transmission and repeatedly grinding them from one gear to another with the clutch only half engaged. Sleep-onset central apnea is a thing, but if it is only occasional and isn't causing major desats or sleepiness issues during the day, it often gets ignored.

Altitude can play a role with those sorts of centrals. So can alcohol issues and drug issues--even from doc-prescribed drugs. That can be counter-intuitive when, as you mention, those things seem to "help" in the short term.

When I am at high altitudes, I can have the sleep-onset problem myself. But during my first few years of PAP use, the thing that kept me from falling into that sleep-onset-central loop was turning off ramp and keeping my pressure high enough for me. That was because it was the obstructive component of my breathing issues that would trigger the central pattern. That made it especially important for my airway to be very stable as I fell asleep. If my airway wasn't stable enough during sleep onset, my brain would panic a little as I tried to fall asleep and my breathing paused. It would feel my airway change and it would overreact to that. That caused little panics/anxieties that were not related to anything other than the state of my airway, and it was subconscious. My eyes would sometimes pop open in a panic as I started to transition into sleep, and it took me a while to figure out what was going on. If I took a benadryl, that took the edge off of that process so that I would idle between wake and sleep without going fully conscious. It seemed to help but was not a good habit to get into. Now that I have been on PAP for a number of years, my brain has relaxed about my breathing to the extent that this no longer happens to me unless I am at high altitude.

So a doc may say "it's anxiety" and you may feel some anxiety when falling asleep. Figuring out whether there is a direct cause from what has happened during the day may help alleviate that, yes. But for some of us, sleep itself becomes the anxiety and the state of our airway can be a big part of that as a secondary factor during those times.

None of the above may have anything useful for what you are experiencing. I am talking more about sleep-wake junk than a solid pattern of centrals. But I think the principle still applies, so at least take away the concept that keeping the airway very stable to prevent any narrowing during sleep onset can sometimes, for some people, at least me, prevent a cascade of repeated central apneas, even the regular patterned ones. Yes, for some people it can also involve CO2 sensors in the body and a sort of CO2 feedback loop and stress and insomnia and drugs and alcohol and a host of other things. But narrowing of the airway, the obstructive component, should never be discounted in the process of looking into those other things, even when no obstructive events are being recorded by the machine.

One way of thinking about it, as an over-simplification, is that the line between central apnea issues and UARS-ish sleep issues is a very fine line for some of us during sleep onset. Centrals are centrals, but a stable airway can help fix them over time, for some of us, too. For me, that means never ever trying to fall asleep without the mask on. I don't want my brain to become afraid of sleep again.

Patterned centrals with regular waxing and waning are not well understood yet. The CSR pattern is only really useful because it is associated with a particular set of other health problems. But other forms of central apnea are still mostly mysterious.

Thank you guys for your input and insight.

Fortunately, I can rule out altitude here in the middle america.

I haven't ever woken up (that I can remember) while falling asleep, but I do have some general anxiety that I take pills for (lexapro), so my brain subconsciously worrying about breathing definitely sounds plausible. I've heard good tings about meditation, so perhaps I should swap out some whiskey for zen.

I had changed my flex from a 3 (max) down to 1 (min) and back up to a 3 since I've had the machine. I'll try out at 1 for a bit and see if it improves. Or can I turn it off completely from the clinician's menu?

I've seen some PB before for short bits on some other days but never anything major, and usually without any apneas tied in. Does anyone have a sleepyhead graph some flagged PB that looks like CSR? It would be nice to know what to look out for. Does PR actually flag CSR as PB? seems like it would be difficult to do with software, but who knows.

And is CSR an issue anytime it shows up? or is it worth ignoring if it shows up with sleep onset?

Sorry for all the questions, I'm a curious guy. I thought about raising these questions to my sleep doctor, but I think you guys know more than she does.

Thanks again.

Real PB flagged by a Respironics machine and it's definitely CSR. This person had a LOT of it and ended up being on a different machine.
Don't let the fact that they aren't labeled centrals confuse you. They were central in nature and the machine just had trouble naming them. He had some significant heart disease issues as well.




and Encore


And what I call boring PB which is nothing but a little waxing and waning of the air flow and means nothing exciting.

JolietJake wrote: ↑

Tue May 22, 2018 10:43 am

And is CSR an issue anytime it shows up? or is it worth ignoring if it shows up with sleep onset?

Although the question about sleep-onset centrals is simple and should have a clear answer, I don't think all docs would answer it the same way, from what I've read. Most docs would likely want sleep-stage, brain-arousal, and O2-desat information to feel they could comment, and intermittent issues are rarely captured well in a lab/center. Add to that the fact that the answers to the questions of whether the phenomenon is "frequent" or "continuous" would be somewhat subjective, as would the question of how disturbed YOU feel your sleep is from it happening, and it do get complicated. Many docs might defer to your judgment if you feel the issue is anxiety related and might therefore point in that direction for "solving" the "problem." Other docs might suggest a form of calibrated bilevel that might be set up specifically to lull you to sleep with the most comfortable form of PAP (ahem, ResMed bilevel, cough), which would be a good reason to keep your doc in the loop.

I'm not even sure all scoring programs, techs, and sleep docs would be on the same page on how to score repetitive sleep-onset centrals. I think some docs want to know and want everything scored to help them make arguments to payers later, and other docs are more interested in what happens when someone is solidly asleep awhile so that the difficulties of scoring N1 don't intrude on what the doc wants to know about.

I would say that if it bothers you in the context of the quality of your sleep, that's what sleep docs are paid to know about and comment on and act on. You probably don't want to hide that concern from your team. But I would say, as a fellow patient with no medical training whatsoever, that I am unaware of any real likelihood that what you posted and are experiencing are symptoms of any serious medical issue beyond breathing well during sleep and while falling asleep. Based on my personal experience, I would respect the option of working on my sleep hygiene, as you mentioned, and seeing if I could address it myself. So I think it falls solidly on the "judgment call" line.

JolietJake wrote: ↑

Tue May 22, 2018 10:43 am

Sorry for all the questions, I'm a curious guy.

Ask as many questions as you want. Pugsy and Palerider love curiosity! And we like reading their answers.

JolietJake wrote: ↑

Tue May 22, 2018 10:43 am

I thought about raising these questions to my sleep doctor, but I think you guys know more than she does.

Well we have our angle here, but sleep docs can know things about your history and medical situation that we could never know, so please allow your medical team to assure you from their angle, too.

For example, it may be (and I have no idea either way) that a slight tweak to your Lexapro dosage, or even a switch of medications, may help some people with sleep onset issues related to sleep-breathing. It might be good to give the doc a chance to tweak that sort of thing, if there's any chance it is related. I would at least ask, just in case. And I would include in that discussion a frank up-front disclosure of any other substances that might be coming into play.

If curious about the details of what affects some of us during the transition to sleep and how it relates to CSA, you may find this material interesting to stimulate further research:

The transition from wakefulness to sleep is an inherently unstable period in terms of cardiorespiratory control. With sleep onset, there is a loss of the wakefulness stimulus and behavioral influences. In addition, several respiratory control mechanisms are down regulated at sleep onset. Upper airway (UA) dilator and respiratory pump muscle tone is reduced, and there is an accompanying increase in UA resistance leading to a reduction in ventilation for a given level of drive. Chemosensitivity is also likely reduced at sleep onset. Although of variable magnitude and rate, these normal physiologic responses occur in all individuals. Should the withdrawal of the wakefulness drive be rapid at sleep onset, this in itself may be sufficient to promote hypopnea/apnea due to the delay required to elicit an appropriate compensatory response from the chemoreceptors. Thus, the dysrhythmic breathing characteristics observed even in healthy individuals at sleep onset likely relates to a combination of state instability and the associated changes in chemoreceptor sensitivity. -- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2287191/

Hi JolietJake,

What you show in your second diagram are certainly centrals - but it may be that they are not pathological.

There is a stage or kind of sleep call hypnagogic - a state which some say is allied to problem-solving and creativity.

Those 20 minutes might be that.

I note that your resps per minute in this period is 8 or 9. And there's nothing wrong with that when awake. When I'm awake, and not moving about, my resp rate is almost always under 10.

I also note that, during those 20 minutes, your tidal volume moves up in a very regular fashion to peaks of 900 or 1000 cc (the average single TV for men while awake is 500cc). So one might conclude you're not seriously short of oxygen during that time.

In support of that observation - your median tidal volume is 340cc and your median resp rate is 15 - which tends to suggest your lungs are working fine, and you're pretty healthy at that.

So. Hypnagogic. Not, I'm suggesting, pathological. Just useful for certain purposes.

Thank you for the visuals, that helps a lot! I suppose I'll rely on the machine to flag it before I worry too much.

I may still visit my sleep Dr because I am so curious about these centrals. And it has actually crept my AHI up to a 5 average over the last 2 weeks which would be worth of review from their standpoint. I'll keep researching, and thanks for the link.
If they are to be ignored/discounted, then I'll have to do the math to take them out of the AHI.

It does appear to be a very grey and mysterious are the space between wake and sleep. I'm always amaze at home much we don't know.

Thanks again for the input guys, I feel much more educated and at ease.