SWS, Wader, RG, There is one major factor missing in that study. Who paid for it. It very well might have been funded by a group of SLEEP CENTERS trying to prove that auto's don't work.
Unfortunately in this day and age, you not only need to know how they did the test, but WHY they did the test, and who paid for it.
Finally slept through the whole night....
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wading thru the muck!
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-SWS,
I'm not talking about an artificial breathing machine. I'm talking about a machine in which you could input the actual wave form of the brathing patterns of an actual human being and then replicate it with each machine to see which works better. I understand that this may not be perfect because there is a certain amount of interaction between each machine and the user. I'm sure this type of thing IS being done by each individual manufacturer in the development of their algorithms. It would be nice to apply this technique to a range of machines and see how they compare for an individual user.
I guess we are probably getting ahead of ourselves. What we need is for several prestigeous universities to conduct independant studies regarding the efficacy of the APAP. Hopefuly these will demostrate the benefits that many of us have found in our own use.
I'm not talking about an artificial breathing machine. I'm talking about a machine in which you could input the actual wave form of the brathing patterns of an actual human being and then replicate it with each machine to see which works better. I understand that this may not be perfect because there is a certain amount of interaction between each machine and the user. I'm sure this type of thing IS being done by each individual manufacturer in the development of their algorithms. It would be nice to apply this technique to a range of machines and see how they compare for an individual user.
I guess we are probably getting ahead of ourselves. What we need is for several prestigeous universities to conduct independant studies regarding the efficacy of the APAP. Hopefuly these will demostrate the benefits that many of us have found in our own use.
Sincerely,
wading thru the muck of the sleep study/DME/Insurance money pit!
wading thru the muck of the sleep study/DME/Insurance money pit!
Mike, I think your point is a very valid one. Regardless of ulterior market-driven motive being at fault or simple human oversight, it's important for all of us to realize that even highly revered "medical studies" are not at all above being very poorly designed in my opinion. I have read plenty of medical studies with diametrically opposed conclusions. Very cool avatar, BTW!
The machine responds to the patient. The patient then responds to the machine. The machine then reiteratively responds back to the patient for crucial adjustments. That is the two-way loop that is broken in the study and your proposed machine. There must be a patient response (simulated or real) to truly test the algorithm. To rely on lobbing one obstrutive sleep event (even repeatedly) is like assessing world-class tennis players using only a serving machine. It just doesn't make for any sort of useful comparison in my opinion.
Wader, the point I was trying to get accross is that simply lobbing a single and unresonsive recorded or artificial sleep event into an AutoPAP is in and of itself inherently flawed and of little use. An AutoPAP algorithm will very often require several iterations of: 1) pressure adjustment, 2) patient breath detection, and 3) pressure re-adustment based on step 2.I'm not talking about an artificial breathing machine. I'm talking about a machine in which you could input the actual wave form of the brathing patterns of an actual human being and then replicate it with each machine to see which works better.
The machine responds to the patient. The patient then responds to the machine. The machine then reiteratively responds back to the patient for crucial adjustments. That is the two-way loop that is broken in the study and your proposed machine. There must be a patient response (simulated or real) to truly test the algorithm. To rely on lobbing one obstrutive sleep event (even repeatedly) is like assessing world-class tennis players using only a serving machine. It just doesn't make for any sort of useful comparison in my opinion.
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Guest
I agree with SWS, or at least with what I perceive him to be saying...
I've never really liked simulations for studying effectiveness of something, because your test is limited both by the efficacy of your treatment AND the validity of your simulation.
The fact is that I'm just not convinced that a simulated breathing machine is going to provide exactly the breathing response I or any other human being will, and in building the simulation, we're basically saying "Hey, this is how we THINK it works, so let's test to see how well our machine reacts to what we think we'll see."
Liam, who breathes differently than anyone else. He breathes through his ears.
I've never really liked simulations for studying effectiveness of something, because your test is limited both by the efficacy of your treatment AND the validity of your simulation.
The fact is that I'm just not convinced that a simulated breathing machine is going to provide exactly the breathing response I or any other human being will, and in building the simulation, we're basically saying "Hey, this is how we THINK it works, so let's test to see how well our machine reacts to what we think we'll see."
Liam, who breathes differently than anyone else. He breathes through his ears.
Wow, I got "Guested". I'm usually pretty good at avoiding that.
That last guest was me, which I guess should be obvious, since I SIGNED the message.
Liam, Captain Obvious.
That last guest was me, which I guess should be obvious, since I SIGNED the message.
Liam, Captain Obvious.
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wading thru the muck!
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-SWS,
Either you and I are speaking in different languages and not understanding each other or Liam has put some kind on a capella hex on us. How do these companies develop these algorithms? They must have apparatus to recreate particular breathing pattern wave forms to test different strategies for preventing them. My guess is for each individual there a limited number of obstructive wave forms that occur. If they can be exactly replicated and fed to each machine to see how it reacts, this would be useful information. I understand in a perfect world we would all just try each machine for six months and then see which one gave us the best results. Then we would hope that from the beginning to the end of this two year test period our requirements had not changed and made all the data irrelevant. My guess is the NTSB would like to do automobile crash tests with real people instead of crash dummies but they are lacking for volunteers.
Either you and I are speaking in different languages and not understanding each other or Liam has put some kind on a capella hex on us. How do these companies develop these algorithms? They must have apparatus to recreate particular breathing pattern wave forms to test different strategies for preventing them. My guess is for each individual there a limited number of obstructive wave forms that occur. If they can be exactly replicated and fed to each machine to see how it reacts, this would be useful information. I understand in a perfect world we would all just try each machine for six months and then see which one gave us the best results. Then we would hope that from the beginning to the end of this two year test period our requirements had not changed and made all the data irrelevant. My guess is the NTSB would like to do automobile crash tests with real people instead of crash dummies but they are lacking for volunteers.
Sincerely,
wading thru the muck of the sleep study/DME/Insurance money pit!
wading thru the muck of the sleep study/DME/Insurance money pit!
In my opinion, there is a difference. Crash test dummies can be made to perfectly mimic a human body, in so far as they're really just measuring device. A few joints in the right places, proper heights and weights, and you're there.wading thru the muck! wrote:My guess is the NTSB would like to do automobile crash tests with real people instead of crash dummies but they are lacking for volunteers.
That is (to me) quite a lot different from trying to build a machine which mimics the subtleties of breath response in order to test a CPAP machine.
This probably comes from being a programmer, but I don't like to write programs to test my programs, and I don't like to test my own programs. Not because the work is tedious, but because as the author of the code, I know how I expect it to be used, and subconsciously, I'm going to test it in the same fashion. I need someone who DOESN'T know how it works to test it and maybe try something that I would never have thought to try, and see how the code reacts.
I've found the more complex the piece of software I have to write in order to test my other piece of software, the more likely that any discrepancies I find turn out to be in the testing code rather than the original, tested code. I feel the same way here. AutoPAPs are very complex and subtle in the way they work. I'm frankly astounded when I think of what they can accomplish through the very minimal input of measuring your breath and maybe listening for your snores.
They are SO complex and subtle that it requires an equally complex test case, and thus the chances are you will build a test case which is very complex, but not realistic to the real world, and then build an APAP which responds "perfectly" to the test case, but turns out not really to be of any use at all on people.
I think such a test machine might be useful during initial development, but ultimately it requires human trials and human subjects to perfect it, to make sure that you've perfected your algorithm to the real world complex situation.
Does that make sense?
Liam, who's really just trying to get out of testing his own code.
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Wader, my guess is that they start off with pure simulation. They simulate both the machine (since that detection/response algorithm is of the essence)---and they simulate patient breathing patterns. Once the AutoPAP is a physical reality (proto-type or otherwise) they would likely require a responsive breathing pattern (simulated or otherwise). Perhaps this example will clarify what I am trying to say:
Take the AutoPAP you currently use---the REMstar Auto. Recall exactly what it does to "non-responsive" apneas at over 8 cm. On that single obstructive sleep event (not a succession of several events) the REMstar Auto will attempt exactly three pressure increments before changing its pressure response altogther. At that point the REMstar Auto will actually back pressure down for fear of inducing central apneas. That was but a single obstructive event that the REMstar needed that two-way closed loop I referred to. That sequence on just one obstructive event went like this:
REMstar Auto Algorithmic technique for but a SINGLE sleep apnea event:
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1) apnea detected,
2) increase pressure for the first time
3) measure patient airflow
4) if airflow reflects "unresponsive" or uncorrected condition, increase pressure for the second time
5) measure patient airflow,
6) if airflow reflects "unresponsive" or uncorrected condition, increase pressure for the third time
7)measure patient airflow
8) if airflow still reflects "unresponsive" or uncorrected condition, decrease pressure for fear of inducing central apneas
Those eight steps require a two-way patient-to-machine feedback loop. Those eight steps are for but one obstructive sleep event. A breathing machine or simulator that cannot provide a patient response would actually be useless on the REMstar Auto. If that test machine could not breathe back (show a responsive airflow pattern) in response to those pressure increment attempts, then all apnea breathing patterns artifically introduced into the REMstar Auto would be interpreted and treated as typical "unresponsive apneas" verus typical "obstructive apneas". That's a broken test BIG TIME!
Do you see what I am getting at? The breathing simulator with the broken patient feedback loop used in the medical study above doesn't measure didley squat for the REMstar Auto.
Liam presents an altogether different point that is extremely valid in my opinion.
Take the AutoPAP you currently use---the REMstar Auto. Recall exactly what it does to "non-responsive" apneas at over 8 cm. On that single obstructive sleep event (not a succession of several events) the REMstar Auto will attempt exactly three pressure increments before changing its pressure response altogther. At that point the REMstar Auto will actually back pressure down for fear of inducing central apneas. That was but a single obstructive event that the REMstar needed that two-way closed loop I referred to. That sequence on just one obstructive event went like this:
REMstar Auto Algorithmic technique for but a SINGLE sleep apnea event:
===================================================
1) apnea detected,
2) increase pressure for the first time
3) measure patient airflow
4) if airflow reflects "unresponsive" or uncorrected condition, increase pressure for the second time
5) measure patient airflow,
6) if airflow reflects "unresponsive" or uncorrected condition, increase pressure for the third time
7)measure patient airflow
8) if airflow still reflects "unresponsive" or uncorrected condition, decrease pressure for fear of inducing central apneas
Those eight steps require a two-way patient-to-machine feedback loop. Those eight steps are for but one obstructive sleep event. A breathing machine or simulator that cannot provide a patient response would actually be useless on the REMstar Auto. If that test machine could not breathe back (show a responsive airflow pattern) in response to those pressure increment attempts, then all apnea breathing patterns artifically introduced into the REMstar Auto would be interpreted and treated as typical "unresponsive apneas" verus typical "obstructive apneas". That's a broken test BIG TIME!
Do you see what I am getting at? The breathing simulator with the broken patient feedback loop used in the medical study above doesn't measure didley squat for the REMstar Auto.
Liam presents an altogether different point that is extremely valid in my opinion.
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wading thru the muck!
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I'm getting frustrated by this topic because I think we are working towards different goals.
IMHO it has got to be much easier to create a machine to replicate breathing patterns AND responses to algorithmic therapy than it would be to create a crash dummy that reacts a a human being would in an auto crash.
Am I at least right on this one? Come on guys...throw me a bone here!
IMHO it has got to be much easier to create a machine to replicate breathing patterns AND responses to algorithmic therapy than it would be to create a crash dummy that reacts a a human being would in an auto crash.
Am I at least right on this one? Come on guys...throw me a bone here!
Sincerely,
wading thru the muck of the sleep study/DME/Insurance money pit!
wading thru the muck of the sleep study/DME/Insurance money pit!
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rested gal
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Complicated stuff. In my non-techie opinion, no matter how perfectly one person's sleep disordered breathing pattern were recorded and used for playback in a "replication" machine later, I can't see how that would allow any autopap machine to show it how would perform with the live person in a live sleeping situation.
The breathing feedback from the patient is an absolutely crucial part of making an autopap decide "what to do next". No matter how complex and perfect the recording of a patient's sleep disordered breathing one night was, I don't see how any useful conclusion could be drawn from playing just that recording back in a replication machine and having an autopap supposedly deal with it....without allowing that autopap to get real time feedback from the real patient.
Using only a replication of the patient's sleep disordered breathing, one machine could look like it handled the patterns well and another machine could look like it failed to take correct actions. But the fact would remain... in such a replication test, no matter how perfectly the original recording copied a single person's sleep disordered breathing patterns, during the test itself there'd be no patient breathing back into the machine....no feedback at all for the machine to base its next decision ...its next "moves" on.
A machine that looked "on paper" like it failed (with no feedback breathing) could actually be the best machine of all for that patient if hooked to the same living, breathing patient - this time actually getting feedback for its decisions. Depending on whether a machine was getting real feedback or not could make all the difference in the world, imho, in how it would behave.
Without actual minute to minute feedback breathing from a live patient hooked to it, I don't see how any autopap could show what it truly would do. Replicated breathing patterns from a patient just couldn't give that essential (and often subtle) feedback, imho.
Wader, it really is an intriguing idea...the kind of machine you're talking about. I just don't see how a patient's response could ever be programmed into it other than so crudely that it still wouldn't give meaningful data. I may be all wrong, but each response (patient or machine) depends on the previous response. How would you ever get all those building-upon-each-other responses sorted out?
The breathing feedback from the patient is an absolutely crucial part of making an autopap decide "what to do next". No matter how complex and perfect the recording of a patient's sleep disordered breathing one night was, I don't see how any useful conclusion could be drawn from playing just that recording back in a replication machine and having an autopap supposedly deal with it....without allowing that autopap to get real time feedback from the real patient.
Using only a replication of the patient's sleep disordered breathing, one machine could look like it handled the patterns well and another machine could look like it failed to take correct actions. But the fact would remain... in such a replication test, no matter how perfectly the original recording copied a single person's sleep disordered breathing patterns, during the test itself there'd be no patient breathing back into the machine....no feedback at all for the machine to base its next decision ...its next "moves" on.
A machine that looked "on paper" like it failed (with no feedback breathing) could actually be the best machine of all for that patient if hooked to the same living, breathing patient - this time actually getting feedback for its decisions. Depending on whether a machine was getting real feedback or not could make all the difference in the world, imho, in how it would behave.
Without actual minute to minute feedback breathing from a live patient hooked to it, I don't see how any autopap could show what it truly would do. Replicated breathing patterns from a patient just couldn't give that essential (and often subtle) feedback, imho.
Wader, it really is an intriguing idea...the kind of machine you're talking about. I just don't see how a patient's response could ever be programmed into it other than so crudely that it still wouldn't give meaningful data. I may be all wrong, but each response (patient or machine) depends on the previous response. How would you ever get all those building-upon-each-other responses sorted out?
Last edited by rested gal on Sun Mar 06, 2005 3:45 pm, edited 1 time in total.
Yes, you are right, except... IMO, the intent of the crash test dummy is to measure the GROSS forces experienced by a body of a set shape, weight and charactaristics in an accident, not the subtle ones. So I don't think there's particularly that much lost in translation when we don't account for a fear-induced tightening of muscles, or a "hands thrown in front of face" reaction, because I don't believe that's what they're trying to test.wading thru the muck! wrote:IMHO it has got to be much easier to create a machine to replicate breathing patterns AND responses to algorithmic therapy than it would be to create a crash dummy that reacts a a human being would in an auto crash.
Am I at least right on this one? Come on guys...throw me a bone here!
So yes, I think you are arguing down a different path than I perceived you to be.
S'okay. We still love you.
Liam, coughing and trying to look manly after the uncharacteristic and unmanly show of affection for another man.
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Sorry for the frustration Wader. Perhaps I just don't understand the concept of a crash test dummy that breaths into an AutoPAP. My point is a breath introduced into an AutoPAP that does not respond in any way whatsovever, necessarily fails to provide any feedback to the machine that is essential to the algorithm. That one-way crash-test-dummy approach necessarily side-steps and potentially breaks the very algorithm that you are trying to test.
I am sure that once again I am not explaining myself adequately. Ugh!
I am sure that once again I am not explaining myself adequately. Ugh!
Yup, Wader! I'm having a hard time reading today without the words jumping around on the page---my own little attention deficit symptom. On days like today I can still analyze a-okay, I can slowly and sequentially type text out just fine (with plenty of rereading and editing), but I cannot easily or accurately read pages of text without my little cognitive problem hindering me. No wonder you are frustrated trying to communicate with me!
However, you are right! The objective would be to create the initial breathing pattern AND the breathing response----exactly as you said!!! Again, I apologize that I am not reading individual words and sentences very well on a day like today. Who knows what other key points you and others have posted that I have missed? Most days are not cognitively as bad as today for me (regarding reading), but I have plenty of days like this. I used to get this problem as a kid too. Untreated sleep apnea just aggravated the heck out of it. With CPAP/AutoPAP I'm back to moderately flawed cognitive life as it was before untreated apnea.
Again, sorry!
However, you are right! The objective would be to create the initial breathing pattern AND the breathing response----exactly as you said!!! Again, I apologize that I am not reading individual words and sentences very well on a day like today. Who knows what other key points you and others have posted that I have missed? Most days are not cognitively as bad as today for me (regarding reading), but I have plenty of days like this. I used to get this problem as a kid too. Untreated sleep apnea just aggravated the heck out of it. With CPAP/AutoPAP I'm back to moderately flawed cognitive life as it was before untreated apnea.
Again, sorry!
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Guest
Hi Rested Gal,
You are right to the dot....there is no point for a carach dumb simulation except for proto typr test purposues. Nothing beat the real test with full swing real life test. Seem like all the dump test is as good as ready to crash in the market as part of sell first, get feedback, fix some problems, get more new version out and test againand see teh feedback...if works sell more if not good luck to you all that just bought it!
Mckooi
You are right to the dot....there is no point for a carach dumb simulation except for proto typr test purposues. Nothing beat the real test with full swing real life test. Seem like all the dump test is as good as ready to crash in the market as part of sell first, get feedback, fix some problems, get more new version out and test againand see teh feedback...if works sell more if not good luck to you all that just bought it!
Mckooi