Is this even possible?? Heh I seem to think so :s

I am going to do a full sleep study soon (my fourth one) as a few people recommended. Anyways, I am a little scared about having my sleep study done. Is there anything I can take to make myself calm for the sleep study?

Here is the question for the subject headline. Since sleep studies use a belt to see if you have central sleep apnea. Is there anyway that the result can be wrong. I have a feeling that I have an obstructive apnea and my body/brain doesn't attempt to breathe against it and then I would get labeled a central right? But wouldn't the sleep disturbance be caused by the obstruction and not the central? The reason why I worry about this is that my in lab study showed I had nights full of centrals but then my home study showed the opposite and said I have obstructive events and zero centrals. I also breathe pretty shallow/soft which I think contributes to me not attempting to breathe against the obstruction since it requires a bit of force to actually count as a inhale attempt with the belt on. Any thoughts? Suggestions?

sleepinow wrote:I am going to do a full sleep study soon (my fourth one) as a few people recommended. Anyways, I am a little scared about having my sleep study done. Is there anything I can take to make myself calm for the sleep study?

Here is the question for the subject headline. Since sleep studies use a belt to see if you have central sleep apnea. Is there anyway that the result can be wrong. I have a feeling that I have an obstructive apnea and my body/brain doesn't attempt to breathe against it and then I would get labeled a central right? But wouldn't the sleep disturbance be caused by the obstruction and not the central? The reason why I worry about this is that my in lab study showed I had nights full of centrals but then my home study showed the opposite and said I have obstructive events and zero centrals. I also breathe pretty shallow/soft which I think contributes to me not attempting to breathe against the obstruction since it requires a bit of force to actually count as a inhale attempt with the belt on. Any thoughts? Suggestions?

The belt should not be too snug. It is only to know if your lungs are expanding or not. With an obstructive apnea, your lungs will still expand, but the air is block. WIth a central, your lungs make no effort to breathe.

sleepinow wrote:I am going to do a full sleep study soon (my fourth one) as a few people recommended. Anyways, I am a little scared about having my sleep study done. Is there anything I can take to make myself calm for the sleep study?

Bring your Teddy Bear

zoocrewphoto wrote:

sleepinow wrote:I am going to do a full sleep study soon (my fourth one) as a few people recommended. Anyways, I am a little scared about having my sleep study done. Is there anything I can take to make myself calm for the sleep study?

Here is the question for the subject headline. Since sleep studies use a belt to see if you have central sleep apnea. Is there anyway that the result can be wrong. I have a feeling that I have an obstructive apnea and my body/brain doesn't attempt to breathe against it and then I would get labeled a central right? But wouldn't the sleep disturbance be caused by the obstruction and not the central? The reason why I worry about this is that my in lab study showed I had nights full of centrals but then my home study showed the opposite and said I have obstructive events and zero centrals. I also breathe pretty shallow/soft which I think contributes to me not attempting to breathe against the obstruction since it requires a bit of force to actually count as a inhale attempt with the belt on. Any thoughts? Suggestions?

The belt should not be too snug. It is only to know if your lungs are expanding or not. With an obstructive apnea, your lungs will still expand, but the air is block. WIth a central, your lungs make no effort to breathe.

I understand that, but isn't there a chance that my lungs will not expand because a central kicks in right after the obstruction? Like so instance can my obstruction cause a central to occur and therefore it gets labeled as only a central?

sleepinow wrote:I am going to do a full sleep study soon (my fourth one) as a few people recommended. Anyways, I am a little scared about having my sleep study done. Is there anything I can take to make myself calm for the sleep study?

Here is the question for the subject headline. Since sleep studies use a belt to see if you have central sleep apnea. Is there anyway that the result can be wrong. I have a feeling that I have an obstructive apnea and my body/brain doesn't attempt to breathe against it and then I would get labeled a central right? But wouldn't the sleep disturbance be caused by the obstruction and not the central? The reason why I worry about this is that my in lab study showed I had nights full of centrals but then my home study showed the opposite and said I have obstructive events and zero centrals. I also breathe pretty shallow/soft which I think contributes to me not attempting to breathe against the obstruction since it requires a bit of force to actually count as a inhale attempt with the belt on. Any thoughts? Suggestions?

If it is not a home study the brain waves and other data will make it clear.

If your airway is blocked, but your brain isn't trying to breathe, it's still considered a central. i.e. obstructive plus central = central.

This is one of the limitations of CPAP machine data. If it sees a blocked airway, it doesn't flag the apnea as "central" or "clear airway," even if you aren't trying to breathe and it is technically a central apnea.

I guess it's always possible for chest effort belt based central apnea detection to fail to properly detect a "real" central apnea. I don't think it's all that likely, unless you have a bad technician who doesn't set up and monitor correctly.

I suggest everyone insist on getting a sleeping pill prescribed by their doctor to take in case they can't sleep in the lab. Many doctors will resist this idea, because it might affect the results, but not sleeping affects the results even more than a sleeping pill. Also the doctor isn't the one who ends up paying for a failed sleep study.

My Doctor ordered a sleep aid when I first had mine. the pill did not really do much of anything it seemed though.

BlackSpinner wrote:

sleepinow wrote:I am going to do a full sleep study soon (my fourth one) as a few people recommended. Anyways, I am a little scared about having my sleep study done. Is there anything I can take to make myself calm for the sleep study?

Here is the question for the subject headline. Since sleep studies use a belt to see if you have central sleep apnea. Is there anyway that the result can be wrong. I have a feeling that I have an obstructive apnea and my body/brain doesn't attempt to breathe against it and then I would get labeled a central right? But wouldn't the sleep disturbance be caused by the obstruction and not the central? The reason why I worry about this is that my in lab study showed I had nights full of centrals but then my home study showed the opposite and said I have obstructive events and zero centrals. I also breathe pretty shallow/soft which I think contributes to me not attempting to breathe against the obstruction since it requires a bit of force to actually count as a inhale attempt with the belt on. Any thoughts? Suggestions?

If it is not a home study the brain waves and other data will make it clear.

How would brain waves determine if I have a central or an obstruction or both? I thought they are only used for detecting stages of sleep. Correct me if I am wrong. The more knowledge the better

archangle wrote:
I guess it's always possible for chest effort belt based central apnea detection to fail to properly detect a "real" central apnea. I don't think it's all that likely, unless you have a bad technician who doesn't set up and monitor correctly.

I suggest everyone insist on getting a sleeping pill prescribed by their doctor to take in case they can't sleep in the lab. Many doctors will resist this idea, because it might affect the results, but not sleeping affects the results even more than a sleeping pill. Also the doctor isn't the one who ends up paying for a failed sleep study.

What other methods do baseline sleep studies use to get an accurate central apnea detection other then the belt. I am pretty sure cameras going through the nostrils can work but that would probably be too intrusive for them to use as a standard. If the belt is the only thing they use, then I think that is pretty dumb. The reason being is that we have drones up in the air and soon driverless cars for everyone yet we use a method of breathing efforts using a belt to score a central apnea when it is not 100% accurate. Anyways fill in if I am wrong

I may try some melotonin and maybe a calming herbal tea as they seem to work pretty well. I never tried ambient so I am too scared of using it because I am not informed on what it Is and if there are any side effects

sleepinow wrote:

zoocrewphoto wrote: The belt should not be too snug. It is only to know if your lungs are expanding or not. With an obstructive apnea, your lungs will still expand, but the air is block. WIth a central, your lungs make no effort to breathe.

I understand that, but isn't there a chance that my lungs will not expand because a central kicks in right after the obstruction? Like so instance can my obstruction cause a central to occur and therefore it gets labeled as only a central?

The more likely scenario is that the CA comes first and then the airway collapses during the CA. That would explain why your previous sleep test showed a boatload of CAs, but your home machine is mis-scoring them as OAs: Your home machine cannot measure your effort to breathe, and it uses its proprietary algorithm to determine the patency of the airway as a (approximate) indicator of whether the apnea is most likely a CA or an OA. Both the PR and Resmed CA algorithms are more likely to mis-score a CA as an OA than they are to mis-score an OA as a CA.

When the airway collapses after the start of a CA, the problem is the CA itself. Usually the airway opens back up as soon as the brain stirs enough from lack of O2 or the build up of CO2 (caused by the CA) and arouses just enough to restart the breathing effort. Occasionally when the airway collapses during a CA, the patient will start making an effort to breathe but the airway does not open up. So towards the end of the apnea, there's an effort to breathe, but no air is moving into the lungs. Those apneas are scored as mixed apneas on a full, in-lab sleep test.

sleepinow wrote: What other methods do baseline sleep studies use to get an accurate central apnea detection other then the belt. I am pretty sure cameras going through the nostrils can work but that would probably be too intrusive for them to use as a standard. If the belt is the only thing they use, then I think that is pretty dumb. The reason being is that we have drones up in the air and soon driverless cars for everyone yet we use a method of breathing efforts using a belt to score a central apnea when it is not 100% accurate. Anyways fill in if I am wrong

I'm not sure what a "camera inserted through the nose" would be able to "see" in regards to whether there's any effort being made to breathe during an apnea.

Effort to breathe means the diaphragm is moving up and down and the chest muscles are expanding and contracting in a fashion that should cause air to flow into and out of the lungs. The belts around your chest and stomach pick up any movement of the diaphragm and chest muscles used for breathing. A camera inserted through the nose cannot NOT show the diaphragm at all, and hence video from a camera inserted into the upper airway through the nose will NOT be able to show whether there is any effort being made to breathe. The belts are sensitive enough to pick up very slight movements in the abdomen and chest that might NOT be visible on the video that's also being recorded while you sleep and hence they provide very reliable data about whether the diaphragm and chest muscles are moving in a fashion that indicates whether an effort to breathe is being made.

Here's where I think your misunderstanding lies: I think you are still under the assumption that the patency of the airway is important when it comes to detecting CAs. But the patency of the airway is not important at all when it comes to the definition of a real CA.

A real central apnea occurs when there is NO effort to breathe for at least 10 seconds. And because there is no effort to breathe, no air gets into the lungs: If the diaphragm and chest muscles are NOT moving no air will flow into and out of the lungs. The upper airway may or may not collapse during the time there is no effort to breathe, but the root cause of the apnea is that the brain forgot to tell the diaphragm to move up and down---i.e. the brain forgot to send the signal to the body to inhale NOW. And once the brain remembers to send the inhale NOW signal to the diaphragm and chest muscles, breathing resumes and air gets into the lungs. If the airway did collapse during the CA, the arousal that ends the CA and restarts the breathing simultaneously also causes the muscles that control the airway to tighten up enough to open up the collapsed airway. Hence, once the brain starts sending inhale NOW messages to the diaphragm and chest muscles, normal breathing resumes and air gets into the lungs.

A mixed apnea apnea occurs when there is no air getting into/out of the lungs for at least 10 seconds AND the start of the apnea looks like a CA---i.e. there is no effort to breathe being made for several seconds---AND the end of the apnea looks like an OA---i.e. there's a clear effort to breathe being made for several seconds but no air is getting into the lungs. The current understanding about mixed apneas is this: The brain forgets to send a signal to breathe to the diaphragm and chest muscles and a CA starts. During the CA, the airway collapses (due to a combination of over relaxed muscles and no moving air). The brain notices an increase in CO2, which is the brain's usual trigger to send inhale NOW messages to the diaphragm and chest muscles, and it starts sending messages to inhale NOW; so an effort to breathe restarts. But (unlike a normal CA), the muscles responsible for keeping the airway unobstructed do not tighten up enough to open the airway and so the airway remains obstructed. Hence no air is getting into the lungs in spite of the fact that the person is now trying to inhale. After several more seconds, the brain arouses enough to cause the muscles that control the airway to tighten up enough to open up the airway and at that point air starts getting into the lungs.

An obstructive apnea occurs when there is no air getting into/out of the lungs (as measured by the airflow sensor) BUT there continues to be an effort to breathe as measured by the belts. In other words, when you have an OA, you don't actually stop breathing. Rather you continue to try to breathe (sometimes vigorously), but no air is getting into or out of the lungs because of a blocked airway. The brain continues to send inhale NOW messages to the diaphragm and chest muscles throughout an OA, but no air gets into the lungs. Eventually the brain figures out that there's a problem and arouses enough to make the muscles that control the upper airway tighten up enough to open the airway. And at that point air stars flowing back into the lungs.

In the lab, the combination of the sensor for picking up the airflow into/out of the lungs, the belts to measure that measure effort to breathe, and the EEG to determine sleep/wake are all important in determining whether an apnea is a central apnea, an obstructive apnea, or a mixed apnea. And when the data from all three sources is looked at simultaneously, it's not difficult for a tech to spot the difference in how a CA looks versus an OA or a mixed apnea looks.

Home machines have no way to gather data about the effort to breathe. They can measure is how much air is moving into and out of the lungs AND they can approximate the patency of the airway by proprietary algorithms. Those algorithms are reasonably accurate in figuring out whether the airway is clear or blocked. The home machines assume that

• "algorithm says blocked airway" = OA
  "algorithm says clear airway" = CA

This assumption means that it is unlikely for a real OA to be mis-scored as an CA since the airway does collapse in a real OA. But this assumption also means that most (or all) mixed apneas will be mis-scored as OAs and that some central apneas will be mis-scored as OAs since the airway can collapse after the start of a CA.

Moreover the accuracy of the CA detection algorithms is also somewhat pressure dependent. In other words, the Resmed FOT and PR PP algorithms are more likely to classify a clear airway as an obstructed airway at higher pressures.

sleepinow wrote:What other methods do baseline sleep studies use to get an accurate central apnea detection other then the belt.

I think the belt is it for most in-lab sleep tests. There might be something else used in research studies. Belt failures really shouldn't be a problem in practice because you can see that the chest effort belt is working when the patient is breathing before and after the apnea.

They can sometimes get some sense about "clear airways" by seeing the heartbeat in the air pressure. The varying blood pressure on the other side of the membrane in the alveoli makes a very small change in the pressure of air in the lungs. I've read that they used to use this somewhat, but that the signal is pretty weak, somewhat iffy, and needs a real good tech to be able to see it. The discussion I saw suggested that they don't usually rely on that any more. The "heartbeat signal" technique would suffer from the same problems as FOT or pressure pulse in that it detects a clear airway, not respiratory effort.

ResMed CPAP uses FOT (Forced Oscillation Technique) and PRS1 uses pressure pulses. Both of these send pulses of pressure and try to "see the lungs" to tell if the airway is open. I don't know if any of the lab or in-home sleep tests use this or similar technique.

There are some pretty amazing claims made for Peripheral Arterial Tone devices. I don't know if they can detect centrals. I'm a bit skeptical of PAT tests anyway.

robysue wrote:

sleepinow wrote: What other methods do baseline sleep studies use to get an accurate central apnea detection other then the belt. I am pretty sure cameras going through the nostrils can work but that would probably be too intrusive for them to use as a standard. If the belt is the only thing they use, then I think that is pretty dumb. The reason being is that we have drones up in the air and soon driverless cars for everyone yet we use a method of breathing efforts using a belt to score a central apnea when it is not 100% accurate. Anyways fill in if I am wrong

I'm not sure what a "camera inserted through the nose" would be able to "see" in regards to whether there's any effort being made to breathe during an apnea.

Effort to breathe means the diaphragm is moving up and down and the chest muscles are expanding and contracting in a fashion that should cause air to flow into and out of the lungs. The belts around your chest and stomach pick up any movement of the diaphragm and chest muscles used for breathing. A camera inserted through the nose cannot NOT show the diaphragm at all, and hence video from a camera inserted into the upper airway through the nose will NOT be able to show whether there is any effort being made to breathe. The belts are sensitive enough to pick up very slight movements in the abdomen and chest that might NOT be visible on the video that's also being recorded while you sleep and hence they provide very reliable data about whether the diaphragm and chest muscles are moving in a fashion that indicates whether an effort to breathe is being made.

Here's where I think your misunderstanding lies: I think you are still under the assumption that the patency of the airway is important when it comes to detecting CAs. But the patency of the airway is not important at all when it comes to the definition of a real CA.

A real central apnea occurs when there is NO effort to breathe for at least 10 seconds. And because there is no effort to breathe, no air gets into the lungs: If the diaphragm and chest muscles are NOT moving no air will flow into and out of the lungs. The upper airway may or may not collapse during the time there is no effort to breathe, but the root cause of the apnea is that the brain forgot to tell the diaphragm to move up and down---i.e. the brain forgot to send the signal to the body to inhale NOW. And once the brain remembers to send the inhale NOW signal to the diaphragm and chest muscles, breathing resumes and air gets into the lungs. If the airway did collapse during the CA, the arousal that ends the CA and restarts the breathing simultaneously also causes the muscles that control the airway to tighten up enough to open up the collapsed airway. Hence, once the brain starts sending inhale NOW messages to the diaphragm and chest muscles, normal breathing resumes and air gets into the lungs.

A mixed apnea apnea occurs when there is no air getting into/out of the lungs for at least 10 seconds AND the start of the apnea looks like a CA---i.e. there is no effort to breathe being made for several seconds---AND the end of the apnea looks like an OA---i.e. there's a clear effort to breathe being made for several seconds but no air is getting into the lungs. The current understanding about mixed apneas is this: The brain forgets to send a signal to breathe to the diaphragm and chest muscles and a CA starts. During the CA, the airway collapses (due to a combination of over relaxed muscles and no moving air). The brain notices an increase in CO2, which is the brain's usual trigger to send inhale NOW messages to the diaphragm and chest muscles, and it starts sending messages to inhale NOW; so an effort to breathe restarts. But (unlike a normal CA), the muscles responsible for keeping the airway unobstructed do not tighten up enough to open the airway and so the airway remains obstructed. Hence no air is getting into the lungs in spite of the fact that the person is now trying to inhale. After several more seconds, the brain arouses enough to cause the muscles that control the airway to tighten up enough to open up the airway and at that point air starts getting into the lungs.

An obstructive apnea occurs when there is no air getting into/out of the lungs (as measured by the airflow sensor) BUT there continues to be an effort to breathe as measured by the belts. In other words, when you have an OA, you don't actually stop breathing. Rather you continue to try to breathe (sometimes vigorously), but no air is getting into or out of the lungs because of a blocked airway. The brain continues to send inhale NOW messages to the diaphragm and chest muscles throughout an OA, but no air gets into the lungs. Eventually the brain figures out that there's a problem and arouses enough to make the muscles that control the upper airway tighten up enough to open the airway. And at that point air stars flowing back into the lungs.

In the lab, the combination of the sensor for picking up the airflow into/out of the lungs, the belts to measure that measure effort to breathe, and the EEG to determine sleep/wake are all important in determining whether an apnea is a central apnea, an obstructive apnea, or a mixed apnea. And when the data from all three sources is looked at simultaneously, it's not difficult for a tech to spot the difference in how a CA looks versus an OA or a mixed apnea looks.

Home machines have no way to gather data about the effort to breathe. They can measure is how much air is moving into and out of the lungs AND they can approximate the patency of the airway by proprietary algorithms. Those algorithms are reasonably accurate in figuring out whether the airway is clear or blocked. The home machines assume that

• "algorithm says blocked airway" = OA
  "algorithm says clear airway" = CA

This assumption means that it is unlikely for a real OA to be mis-scored as an CA since the airway does collapse in a real OA. But this assumption also means that most (or all) mixed apneas will be mis-scored as OAs and that some central apneas will be mis-scored as OAs since the airway can collapse after the start of a CA.

Moreover the accuracy of the CA detection algorithms is also somewhat pressure dependent. In other words, the Resmed FOT and PR PP algorithms are more likely to classify a clear airway as an obstructed airway at higher pressures.

I get what your saying about the mixed apnea part. I should have stated the above differently but I meant to ask that can a mixed apnea happen in reverse? For instance, the throat collapses and the brain decides not to breathe because of the collapse. I breathe softly and do not take deep breaths but rather smaller ones. So can the brain cancel all breathing efforts when the throat is closed which would ultimately lead to a central on top of the obstruction if that makes any sense

Oh and by the way, thanks for your big response

sleepinow wrote:So can the brain cancel all breathing efforts when the throat is closed which would ultimately lead to a central on top of the obstruction if that makes any sense

just to be clear, no, your theory makes no sense. the brain's natural reaction when the throat closes is to TRY HARDER to breath. that's why you don't die the first time you have an obstructive apnea.

palerider wrote:

sleepinow wrote:So can the brain cancel all breathing efforts when the throat is closed which would ultimately lead to a central on top of the obstruction if that makes any sense

just to be clear, no, your theory makes no sense. the brain's natural reaction when the throat closes is to TRY HARDER to breath. that's why you don't die the first time you have an obstructive apnea.

I do not see how it wouldn't make sense. You say it is the brains "natural reaction" to breathe harder when the throat is closed. Yes it makes sense but there could be a disorder where instead your brain doesn't attempt to breathe because of the collapse. Just like our brains "natural reaction" during sleep and wake is to breathe. But that "natural reaction" does not occur when a central apnea comes up. It could be something much more rare than just a central apnea. Hell there are so many members on this site that still do not know what the hell is causing there sleep trouble