Definition of "Arousals" in the overnight study?

SAG has it right. The AASM guidelines are what we are supposed to follow. As far as how long an arousal can last, most techs go off of 15 seconds, because when we score an epoch, (30 seconds of record time) if more than half the page is wake than we score it wake. We don't mark arousals if the patient wakes up, they would be considered awakenings.

Alpha intrusion is something completely different, and somewhat harder to treat. With arousals there is usually something causing them, so we find the source of the problem, and treat it. Its not that easy with alpha intrusion. Diets, pills, neuro all have to be checked.

Just to throw this out, don't get to caught up if your CPAP is marking down arousals, because the machine really can't detect the arousals since brain activity can't be monitored. The whole idea of a CPAP being able to "read" respiratory events and arousals should be taken with a grain of salt. I'm not saying all of the readings are false, but I wouldn't put much trust into them. They are more like guidelines, as opposed to real results.

Some very helpful information, polysomnoman. Thanks. And thanks to SAG as always!

Fortunately today's obstructive-targeted CPAP machines limit their scoring guesses exclusively to events that are related to flow signal and/or acoustic pulsations: apnea, hypopnea, flow limitation, snore, and in PB/Tyco's case even cardiac-oscillations indicative of central apneas (only 62% central-apnea sensitivity). The central and complex/mixed targeted machines tend to highlight respiratory dyscontrol parameters such as flow volume, breath rate, spontaneous rate, etc.

With only a single flow-related data channel (a highly sensitive pneumotachograph flow sensor) today's event-data capable machines very wisely avoid guessing at any EEG events such as arousals.

polysomnoman wrote:...Just to throw this out, don't get to caught up if your CPAP is marking down arousals, because the machine really can't detect the arousals since brain activity can't be monitored. The whole idea of a CPAP being able to "read" respiratory events and arousals should be taken with a grain of salt. I'm not saying all of the readings are false, but I wouldn't put much trust into them. They are more like guidelines, as opposed to real results.

What does this look like? Is this a where all the pressures seem to be at the minimum set pressure and then there is a pressure recorded below the minimum set pressure? Can someone provide a link to what that looks like?

I get the very basics of understanding little things like what MAP means (minutes at pressure) but have no clue what all the ups and downs are related too. I understand that they are increasing and decreasing pressures..but in terms of triggering them up and down and if I even have the right pressures etc.

So it is very helpful for a visual learner like me to see all this good stuff. This is a very interesting thread!

Fredman wrote:

polysomnoman wrote:...Just to throw this out, don't get to caught up if your CPAP is marking down arousals

What does this look like? Is this...

There are absolutely no home-based CPAP machines that currently mark down arousals (directly, indirectly, or otherwise). They simply mark down the various flow-sensor type events that I mentioned in my post above.

With that said, we have had at least one otherwise knowledgeable past member who very clearly and repeatedly alluded to being able to accurately interpret arousals and even sleep stage----just by looking at flow data! That kind of "creative" and overextending claim might be what polysomnoman had in mind when he issued that tempering statement. That would have to be pure kindness on polysomnoman's part IMO... Because that "creative" claim of being able to somehow accurately interpret EEG events with only flow data is and was absolutely ludicrous.

No disrespect intended to anyone. Just trying to avoid this particular past-point of utter data confusion on this message board. Contrary to some old posts, there's absolutely no way to correctly interpret arousals, sleep architecture, or any other EEG type events from CPAP flow data. And I think that is the spirit of what polysomnoman was trying to tell us with that tempering statement----about not overextending our data sets to somehow mistakenly interpret arousals.

-SWS wrote:

Fredman wrote:

polysomnoman wrote:...Just to throw this out, don't get to caught up if your CPAP is marking down arousals

What does this look like? Is this...

There are absolutely no home-based CPAP machines that currently mark down arousals (directly, indirectly, or otherwise). They simply mark down the various flow-sensor type events that I mentioned in my post above.

With that said, we have had at least one otherwise knowledgeable past member who very clearly and repeatedly alluded to being able to accurately interpret arousals and even sleep stage----just by looking at flow data! That kind of "creative" and overextending claim might be what polysomnoman had in mind when he issued that tempering statement. That would have to be pure kindness on polysomnoman's part IMO... Because that "creative" claim of being able to somehow accurately interpret EEG events with only flow data is and was absolutely ludicrous.

No disrespect intended to anyone. Just trying to avoid this particular past-point of utter data confusion on this message board. Contrary to some old posts, there's absolutely no way to correctly interpret arousals, sleep architecture, or any other EEG type events from CPAP flow data. And I think that is the spirit of what polysomnoman was trying to tell us with that tempering statement----about not overextending our data sets to somehow mistakenly interpret arousals.

Gotcha! I didn't read carefully enough. Thanks! SWS

polysomnoman wrote:Just to throw this out, don't get to caught up if your CPAP is marking down arousals

No cpap/autopap/bipap/SV machine even attempts to look for or "mark" arousals at all.

They don't, because they can't... they can't, and aren't, trying to monitor EEG (electroencephalogram -- brain wave) information.

polysomnoman wrote:because the machine really can't detect the arousals since brain activity can't be monitored.

Right. There is no EEG information gathered by a cpap/autopap/bipap/SV machine. None. Zilch.
Our treatment machines do not even try to detect arousals.

polysomnoman wrote:The whole idea of a CPAP being able to "read" respiratory events and arousals should be taken with a grain of salt.

Any notion that CPAP can "read arousals" needs several tons of salt.

As -SWS said:

-SWS wrote: we have had at least one otherwise knowledgeable past member who very clearly and repeatedly alluded to being able to accurately interpret arousals and even sleep stage----just by looking at flow data!
---
that "creative" claim of being able to somehow accurately interpret EEG events with only flow data is and was absolutely ludicrous.
---
there's absolutely no way to correctly interpret arousals, sleep architecture, or any other EEG type events from CPAP flow data.

rested gal wrote:

-SWS wrote: we have had at least one otherwise knowledgeable past member who very clearly and repeatedly alluded to being able to accurately interpret arousals and even sleep stage----just by looking at flow data!
---
that "creative" claim of being able to somehow accurately interpret EEG events with only flow data is and was absolutely ludicrous.
---
there's absolutely no way to correctly interpret arousals, sleep architecture, or any other EEG type events from CPAP flow data.

Who was that?

He was a high-spirited and incredibly ornery friend of mine.

Oh, right.....

Although, you know, that Respironics VB algorithm can tell you a lot right now, and you never know what may be in the works...

...then again...

SAG

StillAnotherGuest wrote:Oh, right.....

Although, you know, that Respironics VB algorithm can tell you a lot right now, and you never know what may be in the works...

...then again...

SAG

Seriously interesting IMO.

-SWS wrote:Seriously interesting IMO.

Well, really, when you think about it, it's really not that difficult to algorithmically identify a troubled wakefulness state.

Kinda looks like VB to me, tho.

SAG

Here are my stupid questions for the night, on a related note, just to prove how over-my-head all this stuff is:

What if our home treatment machines all DID come with EEG leads and oximeters and DID score arousals and desats and even factored all that info into the AHI scoring automatically. How much more useful would those numbers be, do you think, on a nightly basis? Would the hassle even be worth it for night-to-night use for the average user? Or isn't the flow-based trending info good enough now? And would that extra info actually help an auto machine know what to do differently if that was factored into the algorithm? Without effort channels, would it even be enough to differentiate a central, for example? Maybe it would be cool if a home auto machine could detect whether you were in REM to change how it acted. And I can see detecting wakefulness for a smart-ramp feature. But other than that, what good would it do a home user to know what the sleep stages were the night before if it didn't change anything about how treatment should occur the next night?

Maybe none of those hypothetical questions really matter, but I might learn something from the answers, if anyone is bored enough to field such nonsense . . .

jeff

Jeff, in that case algorithms wouldn't need to cautiously wonder whether an apnea was central or obstructive above that statistical 10 cm point. Rather, they would correctly differentiate at all pressures and treat accordingly. Additionally, RERAs could be detected... then aggressive pressure-treatment could be attempted, with data-channel results instantly validating or invalidating that pressure response. Etc....

StillAnotherGuest wrote:Well, really, when you think about it, it's really not that difficult to algorithmically identify a troubled wakefulness state.

Agreed. But there may be yet other epidemiologically useful statistical measures hiding in breath variability as well.

polysomnoman wrote:With arousals there is usually something causing them, so we find the source of the problem, and treat it.

(1) This is probably opening a rather large can of worms, but what are some of the common causes of arousals and their treatments?


(2) And do doctors share with patients (upon request) the signal charts that were shown in the Korean training manual --
...... LE - A1
...... RE - A1
...... EMG (submental)
...... C4 - A1
...... Oz - A1
...... V5
...... 50 uv
What form would that data take -- is it printed on regular sheets, or a scroll of paper, or delivered electronically, etc? Would they limit it to just the epochs that have arousals (because of the volume of data)?

I'm obviously not qualified to read/interpret those signals, but perhaps with them I could find someone to see if they can find clues as to the sources of my arousals... (Which I assume are contributing to my continued fatigue.)

Thanks all! (And the post linking to the Nuts and Bolts of Scoring was very informative!)