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Oscar - export daily "details" needed - power of data analysis / correlation
#11
RE: Oscar - export daily "details" needed - power of data analysis / correlation
Hello Paul,

You are doing, and want to go farther faster with greater ability, to the places I would be inclined to go if I were faced with issues I thought were sleep related. I woke up to sleep's importance after damage was done, but thanks to getting an Autoset and direct and lurking advice from AB I'm well treated.

The attached link to a recent post explained how, best I can remember, to get the most detailed level of data my Autoset or VAuto logs (for one  sleep session).

Export Data functionality of OSCAR | Apnea Board


OT, separately and not intending to hi-jack your thread, but doing so to an extent:

Given the kind of data and interpretation approach you have: If you (or any other readers) have thoughts relevant to the following question, please post them.

Work I've done to determine tidal volume drops (TVd) from flow limitations (marked as FL or not) has used 0.5 L as the typical, or baseline tidal volume (TV). From that 0.5 L I've subtracted my measured TV, say 0.45 L, to arrive at a figure for the "fL caused" TV drop (TVd) of 0.05 L. The question nagging me, as I began work on a moving average (MA)  approach last night, was whether it would truly be more meaningful to compute TVd from the local MA rather than from a constant TV baseline. I question that but think most analysts might favor MAs. I believe most Resmed data, other than FR,  is  at a 0.5 Hz rate but are from MA. I do see MA data smoothing as an economic practical way to avoid the higher sampling rate data loads.  

If one has the all-session profile of TV, as determined via integration of the FR curve, it seems more valid to me to use a fixed TV baseline consistent with the overall average TV for the sleep session. If there are long duration significant changes in a TV level, then a time weighted average of those could be used. 

I happened to use 0.50 L baseline for some novice work and didn't realize, until after some posts of images,  that the member's posted example data showed it was closer to 0.40, hence the displayed and estimated TVd was "overstated" nearly 0.10 L. 

To my eye, there are places where MA are good, as in your case for sure, but I think they muddy up matters of interpretation, e.g., when trying to understand timing of a breathing irregularity.
I have no particular qualifications or expertise with respect to the apnea/cpap/sleep related content of my posts beyond my own user experiences and what I've learned from others on this site. Each of us bears the burden of evaluating the validity and applicability of what we read here before acting on it.  (Disclaimer use permitted by sheepless)

 
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#12
RE: Oscar - export daily "details" needed - power of data analysis / correlation
2SB -- doesn't the minute vent have that moving average functionality to it? (I'm never quite sure of how to think about MV vs TV -- mostly they look the same but in different units.)
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#13
RE: Oscar - export daily "details" needed - power of data analysis / correlation
(10-26-2021, 01:49 PM)PaulNL Wrote: I have now taken a third look and compared an actual day and times to find that in -- what seemed to me as not useful data -- hidden there in all the thousands of "Non-Events" (Pressure, EPAP and FLG - whatever the last one means)

The "details" data is just that -- details. It is not intended to be just events.

FLG is the flow limits graph, reported at 4 second intervals. While a flow limit is not called an "event" in terms of measuring AHI, it does represent a restriction in breathing and does result in ResMed machines increasing pressure to prevent flow limits from "growing up" and becoming hypopneas and apneas. Not all CPAP brands consider flow limits in their pressure management algorithm; Philips, for example, does not. ResMed and F&P Sleepstyle do.
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Apnea Board Monitors are members who help oversee the smooth functioning of the Board. They are also members of the Advisory Committee which helps shape Apnea Board's rules & policies. Membership in the Advisory Members group does not imply medical expertise or qualification for advising Sleep Apnea patients concerning their treatment.
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#14
RE: Oscar - export daily "details" needed - power of data analysis / correlation
(10-26-2021, 03:27 PM)2SleepBetta Wrote: Export Data functionality of OSCAR | Apnea Board


OT, separately [...]

To my eye, there are places where MA are good, as in your case for sure, but I think they muddy up matters of interpretation, e.g., when trying to understand timing of a breathing irregularity.

I can not comment on your flow related remarks, but moving average has places where it is useful and others where it is not the right tool as well. The moving average indeed flattens or muddies as you call it the data. But that's what is needed / wanted in some cases -- can be helpful to see trends clearer.
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#15
RE: Oscar - export daily "details" needed - power of data analysis / correlation
(10-26-2021, 09:13 PM)cathyf Wrote: 2SB -- doesn't the minute vent have that moving average functionality to it? (I'm never quite sure of how to think about MV vs TV -- mostly they look the same but in different units.)

Correct. TV is in liters and MV is in liters per minute. The latter is a rolling average.

Before paying attention to these "deeper" terms, I was mixed up about MV. 'Thought "minute" was that adjective pronounced as "minyoot" and that it denoted a tiny sip of air. 

The fact is that a TV is one complete breath, one ventilation cycle; in a perfect world the enclosed areas we see above and below the FR zero axis would be equal (likewise, if the FR curve were numerically integrated to determine the enclosed volumes above and below the axis those would be equal).
I have no particular qualifications or expertise with respect to the apnea/cpap/sleep related content of my posts beyond my own user experiences and what I've learned from others on this site. Each of us bears the burden of evaluating the validity and applicability of what we read here before acting on it.  (Disclaimer use permitted by sheepless)

 
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#16
RE: Oscar - export daily "details" needed - power of data analysis / correlation
(10-27-2021, 12:23 AM)GuyScharf Wrote: The "details" data is just that -- details. It is not intended to be just events.

FLG is the flow limits graph, reported at 4 second intervals. While a flow limit is not called an "event" in terms of measuring AHI, it does represent a restriction in breathing and does result in ResMed machines increasing pressure to prevent flow limits from "growing up" and becoming hypopneas and apneas. Not all CPAP brands consider flow limits in their pressure management algorithm; Philips, for example, does not. ResMed and F&P Sleepstyle do.

Thanks for the explanation! The column in the data is labeled "Events", therefore I was expecting to find there events and not another kind of data ;-)

But I understand that FLG are also some kind of "events", while Pressure changes are not events in that sense, so a more generic label would be somehow clearer, or DetailsAndEvents or something like that. The current column label, with the data which largely did not seem to match to the label, contributed to the fact that I overlooked that indeed there are all non-breathing events listed in that column.

So when that FLG data is also available it might make sense to see if that tells also something valuable. That might help partly to explain why in some nights I have a high AHI value, but feel pretty good during the day or the other way around (although both are more exceptions than the norm).

I was searching now for FLG. I only can find one thread where this acronym is used (http://www.apneaboard.com/forums/Thread-...s-an-index)

http://www.apneaboard.com/wiki/index.php...imitations  does not mention FLG, neither does http://www.apneaboard.com/wiki/index.php...Rate_graph

I found some other threads (e.g. http://www.apneaboard.com/forums/Thread-...Flow-Limit ) which I'll read to learn more about the flow limit (graphs).

In a thread from 2020 you mention that the flow-limit is checked every 2 seconds, here you stated every 4 seconds. When I have a look at my data I see even and uneven seconds reported. It seems to be that they are spaced apart at least 4 seconds, but sometimes also 5 seconds or 9 or something else (so not always a multiple of 4 seconds...) Should I continue the FLG discussion / questions in the another thread (http://www.apneaboard.com/forums/Thread-...#pid358367 )?
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#17
RE: Oscar - export daily "details" needed - power of data analysis / correlation
Guy asked me to jump in here; it's been a while since I looked at the csv export files, and it looks like they need more work...

In particular the FLG data is the value of the Flow Limitation starting at the time in column 1. The data comes from the PLD.edf file at a sample rate of 2 seconds. It is stored in the OSCAR files with a time-delta compression, so what we see in the csv file is the starting time and the value of flow limitation, or earlier in the file the pressure and EPAP value.
The duration mention in the first row applies to apnea and hypoapnea events only.
It might have been better to have two different columns for the data values and the event durations.

It is my impression, from my earlier work, that many of the columns in the daily and session files apply to the P-R machines, and it would be advantageous to only create columns for active data fields. It's on my todo list.
Apnea Board Monitors are members who help oversee the smooth functioning of the Board. They are also members of the Advisory Committee which helps shape Apnea Board's rules & policies. Membership in the Advisory Members group does not imply medical expertise or qualification for advising Sleep Apnea patients concerning their treatment.
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