Posted by often_awake on August 28, 2012 at 22:12:11:In Reply to: Questioning AHI posted by westernjoe on August 26, 2012 at 13:28:53:
I completely agree with this. I would add the following:
1) There have been studies in which people underwent sleep studies multiple times in a short period of time. I can remember one article from Brazil (I think) in which people took 4 sleep studies on consecutive nights. While
the average AHI remained relatively constant over the 4 days, there was an incredible amount of variation among the individual scores. For example, one person had around 10 on one day and 40 the next. That's a big
difference. Interestingly enough, the percentage of time people spent in different sleep stages changed as well. They tended to have a lot of stage 2 the first night, but over time, they got more stage 3 and REM. So people
may be worrying needlessly when their sleep studies indicate no REM sleep.2) Just my opinion, but I don't think all the multitudinous aspects of a person's breathing during sleep can be captured by a single number. One relevant number is the oxygen desaturation index. My ODI was always on the
mild side, even though I was classified as having severe sleep apnea. The ODI correlates well with the portion of the AHI corresponding to apneas and hypopneas with desaturation, leaving the rest--they hypopneas with
arousal but no desaturation--as another valid number. I was about 7 and 23, which is a whole heck of a lot different from 30 and 0.This is important because people with different numbers will generally respond differently to the various available treatments. Which is to say that people with a high AHI but few apneas or hypopneas with desaturation will
probably have a hard time with CPAP--but will be told over and over to try to adhere to a treatment that doesn't help. (Why doesn't it help? Another study showed that APAPs were just about 100% accurate in predicting
apneas, but less accurate in predicting hypopneas. I hypothesize that they're not good at all in predicting hypopneas without arousal. But doctors seem to be ardent devotees to the doctrine of APAP infallibility.)So the tests don't measure useful information, what they do measure is not measured accurately, and the first line treatment offered to patients often doesn't help as much as we're led to believe. And while I do acknowledge
that many people's lives have been turned around by CPAP, there's a lot of room for improvement. I personally would like to see much more research into non-CPAP, nonsurgical approaches.
- Re: Questioning AHI westernjoe 09:24 9/01/12 (4)
- Re: Questioning AHI Gremlin 06:13 9/05/12 (0)
- Re: Questioning AHI westernjoe 09:28 9/01/12 (2)
- Re: Questioning AHI often_awake 01:14 9/12/12 (0)
- Re: Questioning AHI Gremlin 06:08 9/05/12 (0)