Doing my own sleep study - surprising results

dsm wrote:I believe the machines need to be better aligned as to their meanings and measurements of these datum.

They can't be - because there is no agreement on the definition of what they measure. The alignment has to start in agreeing on the definition. But definitions are frequently part of what someone once defined as an "edifice complex" = peoples' favorite theoretical edifice. And the right to decide on the meaning of terminology is at the center of power struggles.

Can you imagine a Respironics engineer suggesting "how about we build our machines in accordance with Resmed's definition of hypopnea"?

The need to agree on the definition of what you measure is well known to people who do research in the social sciences, less so, I guess, in other areas. A discrepant definition will bring about discrepant measurements.

Lewis Carroll wrote: "When I use a word," Humpty Dumpty said <snip> "it means just what I choose it to mean -- neither more nor less"

I just occured to me how funny it was to see this statement by Humpty Dumpty just after he demands to see the calculation of 365-1 "done on paper"....

O.

_________________

Corrected typo in first line of message --- thanks, rg

Guest,

Many thanks for your detailed & indepth points.
I take your point about getting the point re what one AUTO reports vs another.

I guess the engineer side of me is struggling with the implications of your points.

I do know that some in the medical profession (who I have discussed this with) do regard the discrepancies as an issue with current generation AUTOs.

But I take your point that two prescription medications are not going to yield the same 'readout's if such a thing were possible.

Perhaps a concern here is that unless the manufacturers can come up with a better scoring approach, then the reporting discrepancies will be used as a weapon against the wider promotion of AUTOs in therapy.

I will go away & do some more thinking on that particular issue but am very grateful for the other insights re breathing at various stages of sleep. This is really my hot button at the moment

Cheers

DSM

ozij wrote: <snip>
They can't be - because there in no agreement on the definition of what they measure. The alignment has to start in agreeing on the definition. But definitions are frequently part of what someone once defined as an "edifice complex" = peoples' favorite theoretical edifice. And the right to decide on the meaning of terminology is at the center of power struggles.

Ozij,

I believe that if they are both claiming to report HI & AI & AHI, then to avoid damaging the reputation of their AUTO therapies, they need to be able to agree on what these numbers are and mean else each call these numbers by some other name.

I really see a credibility issue that they have to deal with.

They are selling medical equipment.



Cheers

DSM

I really see a credibility issue that they have to deal with.

That lack of standardized definition exists throughout sleep science, DSM. Not just APAPs. You think APAPs differ in how they score events, you should see some of the discrepancies yielded by human sleep technicians scoring the same PSG data charts. Sleep clinics within the same country cannot agree on whether to use AHI or RDI. Medical boards and councils cannot agree on the definition of hypopnea. I found it curious that your sleep tech contacts may have alluded to those discrepancies as if they were unique to APAP algorithms, but not their own profession.

I think everyone very likely agrees that much better standardization is needed throughout sleep science. I personally view those scoring/definition discrepancies as a statement of how immature sleep science happens to be as a branch of medicine and as an industry.

Guest,

You really are reminding me how new prof's sullivan's discoveries (among the many others) & therapy approaches are.

Point taken.

I know that one of my issues is that I don't think I was correctly diagnosed but in reality this whole area is complex and new and it is a fact that the science has come a very long way in a short time.

I am more than impressed at the sophistication inside the many xPAPs I have pulled apart (esp Remstar AUTO wCflex & BiPap Pro2 w Cflex) plus the upper end PB range.

I have seen (with my own eyes) prof sullivan's 1st CPAP machine that used a vaccume cleaner motor. I heard he also had one that used a washing machine motor Hmmm that could have been put to multiple personal uses

DSM

I'm not techie enough to do much more than stick my toe into the water here.

dsm wrote:they need to be able to agree on what these numbers are and mean else each call these numbers by some other name.

Seems I've read that members of the sleep profession themselves...sleep doctors...are not necessarily in agreement themselves as to a single definition of what constitutes an "hypopnea." Nor are sleep clinic scorers all in agreement about the definition of hypopnea: Use the Medicare definition? Look at desats? Look at what happened just before and after? How restricted does the air flow have to be?

I wouldn't expect machine manufacturers to all agree on a single definition of "hypopnea" when even sleep medicine experts with full PSG data right in front of their eyes can differ on what's a hypopnea.

I think ozij hit the nail on the head:
"They can't be - because there in ['is' - obvious typo] no agreement on the definition of what they measure."

In the context of what you had said, dsm, she was referring to machine manufacturers. But that statement applies also to sleep professionals in general when it comes to hypopneas in particular.

Those pesky hypopnea thingies! Whew, I finally got a techie term in there after all...thingies!!

Just wanted to let you know what a great first-night-of-the-new-year I had:

• 0 hypopneas
  0 apneas
  9 total snores; SI = 1.6
  Total usage = 5.79 hrs
  0 bathroom trips
  Pressure = 9 cm.. 3rd night

I've been sleeping 9-10 hours, but we were up late last night, and I only got in a little less than 6 hours. But, you know what: I feel good. Not even a hangover.

This new Aura/Everest is a great interface. I can't believe how stable it is and how well it seals. I've ordered x-large seals. Probably didn't need to, but I will try them. I am using the rubber band trick to assist sealing, but that is such a simple thing to do.

With the discussion of the inconsistency of PAP definition of A/H events that is ongoing on this thread, I wonder if I really had zero A/H events last night? What the heck. I believe I did, so I'm going to feel good about it.

The best to all of you in the new year,

Jerry

Jerry69 wrote:
With the discussion of the inconsistency of PAP definition of A/H events that is ongoing on this thread, I wonder if I really had zero A/H events last night? What the heck. I believe I did, so I'm going to feel good about it.

Jerry, the key is, that if you "feel good," you CAN believe the good numbers. If you didn't feel good thay may very well be wrong.

BTW... I have to look every time I see your avatar to see if this is Jerry or Johnny. LOL!

snoredog wrote:I think 9cm might be your magic number, your numbers are probably not going to get any lower and as you can see you start seeing problem reappear with increased pressure(s).

Snoredog said this when I was experimenting with my CPAP pressure, going first to 4 cm, then to 8, again, and then, 10, getting very good results at 10. Now, I've settled on 9, with the best results. Way to go, Snoredog. Do you go to the track? If so, place a bet for me.

Jerry

_________________

CPAPopedia Keywords Contained In This Post (Click For Definition): CPAP

Guest wrote: <snip>

Set both machines at the same fixed pressure, then compare AI and HI. Only then will you be comparing apples with apples regarding measurement datum. Until then you are measuring the results of two different algorithms, and datum-wise ("readout"-wise) that is tantamount to comparing apples with oranges. Again, expecting to measure the same AI and HI indices out of these two different algorithms is like expecting to measure the same "pain indices" after taking aspirin, then acetaminophen.

You think APAPs differ in how they score events, you should see some of the discrepancies yielded by human sleep technicians scoring the same PSG data charts. Sleep clinics within the same country cannot agree on whether to use AHI or RDI. Medical boards and councils cannot agree on the definition of hypopnea. I found it curious that your sleep tech contacts may have alluded to those discrepancies as if they were unique to APAP algorithms, but not their own profession.

I think everyone very likely agrees that much better standardization is needed throughout sleep science. I personally view those scoring/definition discrepancies as a statement of how immature sleep science happens to be as a branch of medicine and as an industry.

Amen.

Jerry, your 12/31 AHI vs PRESSURE graph shows a curious bump at 10 cm. It is tempting to think that it is a glitch, and that the curve really extinguishes at 9 as you suggest. I have wondered about my own graph of the same, it appears to have two distinct peaks, and with yet another weeks worth of data the pattern persists. My interpretation is that the first peak represents sleeping on my side, for which I would expect lower pressures are adequate. The higher bump at 10 represents sleeping on my back. Not sure if that is the correct interpretation. When I see a bimodal distribution like that I tend to suspect two separate underlying phenomenon. There could be other possibilities, deep sleep vs. light sleep, or something else completely that I haven't thought of yet. (open for suggestios).


I would dare you to try a higher pressure just to see if there is another peak that you didn't know was there. Harder to do with a CPAP, since you have to push against so much pressure all night, just for the curiosity. Easier for me to suggest that YOU do it.

(that's another good reason to rush out and buy an APAP, for the sake of your ongoing sleep study, and so you don't get bored. the OTHER other good reason is that if you really require 9 cm, you could still spend most of your night pushing against 4 or 5, or whatever. And the higher pressures would "happen" only when needed.)

Comments on both "subjects" in this thread:

Jerry,

Nice goin'!
You're reinforcing my point about people taking control of their therapy.



To the others....about the differences in the machines,

I thought Ozij was going to echo my thoughts.....and almost did.

ozij wrote:They can't.......

Can you imagine a Respironics engineer suggesting "how about we build our machines in accordance with Resmed's definition of hypopnea"?

MY thoughts on this have more to do with patents, copyrights, hardware and programming. Unless all of the XPAP manufacturers use the same chips, sensors and programming, there are bound to be differences in the results (even though they might be small ones). It brings to mind the situation with computer chip manufacturers (only there are fewer of these). In one corner you have Intel and in the other you have AMD (Advanced Micro Devices). Actually there was at least another called Cyrix, but in any case, it comes down to a matter of them doing virtually the same thing (running various Windows and DOS operating systems) but yet being different enough to suit the patent and copyright authorities. One can also make the case that Windows itself has to be able to operate on the different CPU's.

In summary, I'm not disagreeing with the other issues that have been brought up with regard to the definition of hypopneas, etc., but I think the manufacturers HAVE to have certain differences built into their machines for legal purposes......and their own product marketing. Let's face it.....they're NOT marketing these machines to you and me......they're marketing them to the sleep docs and DME suppliers. If it wasn't for the users (us), the APAPs (and data-storage CPAPs) probably wouldn't be as popular (sales) as they are because the sellers (evil DMEs) would be pushing the cheapest thing they can make big bucks on. "Thanks" to online sellers like CPAP.COM for supplying us what we need and want at reasonable prices.

I think what IS important is to establish a "base line" with your therapy (regardless of which machine you choose to use) and then try to improve upon THAT. After all, this therapy is about improving our "quality of life". And, for that WE need to get involved......whether it be just finding the right mask, finding the right humidity setting, or tweaking our pressures.

Just my opinions......

Happy New Year all.

Den

_________________

CPAPopedia Keywords Contained In This Post (Click For Definition): respironics, resmed, cpap.com, DME, Hypopnea

Ric wrote:Jerry, your 12/31 AHI vs PRESSURE graph shows a curious bump at 10 cm.

Jerry, on taking a second look at your graph, I realize I can't really tell if there is an OAI or HI data point obscured by the big red dot at 10 cm, or if the big red dot is just an artifact of the curve-smoothing equation (polynomial regression line, or something?). If so, then cancel my above remarks. I would say you have truly achieved CPAP nirvana, and there is nothing more except the endless vacuum of outer space, nothing is to be gained by going there. What a way to start the new year! HIGH FIVE! <slap>

Wulfman wrote: <snip>

MY thoughts on this have more to do with patents, copyrights, hardware and programming. Unless all of the XPAP manufacturers use the same chips, sensors and programming, there are bound to be differences in the results (even though they might be small ones).



I think the manufacturers HAVE to have certain differences built into their machines for legal purposes......and their own product marketing.

neversleeps wrote:

dsm wrote:I do believe that different brands of APAPs have an obligation to report some form of consistency in the data they provide. I tend to feel any statement that implies that these different brands can produce quite different HI & AI values and that this is quite ok, is 'obfusticating' a problem.

I believe I understand what you're saying, and therein lies the crux of the issue being debated. The fact of the matter is, as I understand it, the different manufacturers do not have any such obligation. We may wish they did, but they do not. If they did, would they not then ultimately be reduced to using identical algorithms and identical scoring criteria?

I personally don't view the acceptance of different results from manufacturer to manufacturer as obfuscating a problem, but rather demonstrating the point that they are, in fact, using different methods in obtaining those results.

Ozij wrote:They can't be - because there is no agreement on the definition of what they measure. The alignment has to start in agreeing on the definition. But definitions are frequently part of what someone once defined as an "edifice complex" = peoples' favorite theoretical edifice. And the right to decide on the meaning of terminology is at the center of power struggles.

Can you imagine a Respironics engineer suggesting "how about we build our machines in accordance with Resmed's definition of hypopnea"?

The need to agree on the definition of what you measure is well known to people who do research in the social sciences, less so, I guess, in other areas. A discrepant definition will bring about discrepant measurements.

As usual more information from this message board than I would ever get from my Sleep Doctor and likely more here than he even knows.

Another thought, It could be a conspiracy the makers are changing the measurements to make it appear that their machines treat better than the sleep lab's.

By being able to freely define that our problem is the data can be more easily shape the data to show how good their machines help us.

The true worth of the treatment is how we feel and if we are seeing a benefit in our overall health.

I know , I know, and Yes I do have all the episodes of the X-Files.