Implications of scoring RERAs and Central Hypopneas being OPTIONAL?

[JoeyWallaby]

I'm not sure 100% this is correct because I can't access the AASM scoring manual (paywall)... but from what I've heard on YouTube lectures from sleep doctors, it isn't mandatory to score RERAs and subclassify hypopneas on sleep studies.

The implications of not scoring RERAs is obvious but not subclassifying hypopneas is less obvious. I have some central apneas on my sleep study, not many, just a few. I have hypopneas scored on my sleep study, I thought they were obstructive but now I notice they don't specify obstructive or central... so they could have been 100% obstructive, 100% central or mixed and I have no idea!   

[harrywr2]

2014 AASM scoring manual

If I have read the manual correctly...scoring RERA's  and Hypopnea's at the 3% desaturation level accurately requires an EEG.
There will always be discussion about the benefits of inexpensive screening methods vs the benefits of accurate screening methods.
A $3000 screening test to see if you might benefit from an $800 machine might seem like a poor allocation of financial resources to some.

[JoeyWallaby]

https://www.aastweb.org/blog/scoring-obs...e-criteria

It is an Obstructive Hypopnea if ANY of the following are present:

• Snoring during the event
  
• An increase in the flatting of the nasal pressure flow or PAP flow signal
  
• Paradoxical breathing
  

You can only call the event a Central Hypopnea if NONE of the above is present.

That's it! With a bit of practice and observation, you can identify the difference between the two and find the correct device modality and pressure for your patient.

[JoeyWallaby]

Sources for my claims. I can't access ICSD-3 or AASM Scoring Manual 2.5 without paying, so if somebody with access would like to clarify the accuracy of this information, please do.

https://www.kkh.com.sg/about-kkh/calenda...coring.pdf



https://www.youtube.com/watch?v=Syv7YcHbTCI&t=50m34s


https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3899312/


https://sleepapneamatters.com/apnea-vs-h...a-vs-rera/

[SorryIamNormal]

I'm not sure 100% this is correct because I can't access the AASM scoring manual (paywall)... but from what I've heard on YouTube lectures from sleep doctors, it isn't mandatory to score RERAs and subclassify hypopneas on sleep studies.

The implications of not scoring RERAs is obvious but not subclassifying hypopneas is less obvious. I have some central apneas on my sleep study, not many, just a few. I have hypopneas scored on my sleep study,

This sounds like working backwards to shoehorn CPAP to every man, women, and child on planet earth.  Why find the root cause of anything if you can keep them dependent on a machine for a lifetime.  It's sort of like psychiatric medication.  Once the patient is setup, you get 15 minute 'med checks' (in our case a 1 page summary from EncoreViewer) and then told your numbers are great, get out of my office.

[JoeyWallaby]

Any thoughts on why this isn't mandatory? Just the extra cost of manpower to manually mark RERAs and subclassify hypopneas for what the AASM considers little benefit?

[ApneaQuestions]

I have a background in Seismic Data Signal Analysis. 
If we look at a typical seismogram we see that it's "just a bunch of wiggles".. just like all the OSCAR graphs.
There are lots of automatic algorithms available that detect the shape of these wiggles. 
The simplest of these is "Fourier Analysis" which looks at the frequency content of the waveform.

Just google for "Wavelet Analysis" and you'll immediately see lots of techniques for detecting the shape of wavelets.
If nothing else.. just glance at the images to get a feel for the subject.
Images: https://www.google.com/search?q=wavelet+...20&bih=926

Picking one image at random.. check this out...
https://www.ndt.net/article/wcndt00/pape...9/fig4.gif
Does that look vaguely familiar?
How about this one? :
https://www.researchgate.net/profile/Ala...ons-73.png


These techniques could easily be used to automate the detection of RERA waveforms and to give objective measurements of their "severity".
I cannot think of any good reason why the sleep industry has not jumped onto these techniques decades ago to analyze ALL the data.

Thinking out loud.. they could easily be used in (at least) three ways..
1) Given an existing recording of breathing patterns from the previous night.. detect and classify the presence of RERA waveforms as a function of time.
2) During a titration study, detect the severity of RERA waveforms and see how they change in response to your titration tweaks.
3) With a bit more algorithmic effort... use this information to automate the titration process to optimize the breathing patterns.

So I'm amazed to find out that these techniques are (possibly) not already used in all areas of the sleep industry.
Once the algorithms have been developed, there would be very little "manpower" needed.

Continuing on the theme, the same techniques could be used to automatically detect and quantify Hypopneas, Cheynes-Stokes, Periodic Breathing and indeed ANYTHING that manifests itself in the inherent "shape" of the airflow curves (or any other curve for that matter such as in Polysomnography).
At the end of the day... they are all just "wiggles" and the same mathematical techniques apply for ALL wiggles.

There really is no reason for people to be eye-balling waveforms when these automatic algorithms have been in existence for decades.
$0.02

[SorryIamNormal]

I don't understand half of what you said but I know enough to say 'their' theories doesn't stand up to scrutiny.  I read Dr. Stephen Parks  book and listened to a bunch of his podcasts.  He says sleep apnea is a craniofacial problem and in my personal case I'm certain of that.  But, if your theories don't stand up to scrutiny.... what do you do?  

Stonewall and act authoritarian.  I see cpap as analogous to 'medication managment'.  Run through an algorithm or checklist, prescribe, treat then do minimal followup.  The device companies want to sell as many as possible, along with replacement parts (mind you this is all for life).  Maybe once the camel gets its nose underneath the tent... then all hell will break loose?  They won't even let dentists (training in dental sleep medicine) diagnose sleep apnea or order a PSG.  Cause those MDs gotta defend their turf (and their revenue).    

They can't allow any challenges to their theory.  Then it all comes tumbling down.  It's not about helping people.  It's about establishing a 'good enough' standard that the insurance companies, government, and colleagues/professional associations accept.  Then run that algorithm until exhaustion or collapse.

[ApneaQuestions]

Here's a simple post I put together recently showing the idea behind flow limitations and its impact on the waveforms.
http://www.apneaboard.com/forums/Thread-...#pid323859
Scroll down further after that post and I found the actual paper I used to grab those images.

To a first approximation, the terms RERA and UARS are basically ways of naming those concepts. 
RERA goes a little further and also includes an explicit recovery/arousal.

[JoeyWallaby]

Interesting note... you don't have to score RERAs on a sleep study... but when titrating CPAP, the AASM instructs to titrate until RERAs subside.

So they're not worth scoring on sleep studies but worth titrating away?