Hello Guest, Welcome to Apnea Board !
As a guest, you are limited to certain areas of the board and there are some features you can't use.
To post a message, you must create a free account using a valid email address.

or Create an Account


New Posts   Today's Posts

Oscar sessions seem wrong
#21
Progressive AHI
Would you be kind enough to thoroughly check my reasoning here.

Given AHI = (Number of Events in a session) divided by (Duration of Session)
OR AHI = NES/DOS
AHI for numerous sessions = (NES1 + NES2 + ... + NESn)/(DOS1 + DOS2 + ... + DOSn)
OR AHIn = SUM_NESn / SUM_DOSn

By calculating AHIn for each time period from the beginning, you get a PROGRESSIVE AHI (See Progressive_AHI.png)

My results show that whatever I did between 03-Jan-22 06:00 and 10-Jan-22 06:54 resulted in lowering my AHI.
The same goes for each decreasing slope.

But my overall actions did not succeed yet to reduce my end AHI which has progressed to 3.29.
If I just maintain the last figure, I should be OK since it is below 5.0.

The last 2 sessions show a little decrease so I should keep doing what I have been doing for those two nights.

I wanted a picture of the effectiveness of my treatment and unless there is a flaw in my reasoning, I believe I now have that picture.
Although not perfect because there are other factors involved in the quality of sleep, I believe it is a good indicator.

DanEm

"If life hands you lemons, make lemonade! Words to live by, especially when you keep in mind that the only way to make them into lemonade is to squeeze the hell out of them."
Post Reply Post Reply






Donate to Apnea Board  
#22
RE: Oscar sessions seem wrong
The AHI for a day is calculated as (total # events for the day)/(total duration for the day), where a day runs from noon to noon. So, yes, your formula appears to be correct, provided NES and DOS are correct. The way OSCAR calculates total number of events for the day is to add together the number of events in each session of the day.

Are you counting all the events that are used in the AHI calculation? OA + H + UA + CA, and not any of the others?

I don't understand how you are calculating a "progressive AHI". If it's just daily AHI, it should match the AHI graph on the Overview page, but it doesn't.
Useful links
Download OSCAR (current version is 1.4.0)
Best way to organize charts
How to attach charts to your post

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.
Post Reply Post Reply
#23
RE: Oscar sessions seem wrong
Quote:The AHI for a day is calculated as (total # events for the day)/(total duration for the day), where a day runs from noon to noon.

It is the same formula for a Session.(total # events for the session)/(total duration for the session) and the session has a start and end time.


Quote:Are you counting all the events that are used in the AHI calculation? OA + H + UA + CA, and not any of the others?

If you have the AHI value then you have all the events that are used in the AHI calculation and no other.
So, you can get the total # events with the formula

(total # events) = (AHI) x (total duration)

Oscar provides all those.
AHI for sessions and days
Duration for sessions and days

The progressive value is 

For 1st session  AHI = (total # events for the session)/(total duration for the session)
For 2nd session AHIn(total # events session 1 + total # events session 2) / (total duration session 1 + total duration session 2)
For 3rd session AHIn = (total # events session 1 + 2 + 3) / (total duration session 1 +2 + 3)
Or for n sessions

AHIn = Sum (# events per session) / Sum (total duration per session)

So it gives you a "progressive" value for AHI or the (AHI for 1st session), the (AHI for sessions 1 & 2), the (AHI for sessions 1 & 2 & 3), and so forth to "n" sessions.

The value you get for the last session (or day if you do the same) is the AHI for (total number of events) / (total duration).

On a previous post, you were right to mention it is not a sum nor an average of the AHI.  Rather a calculation of AHI for the entire period.

I hope I am clear with this.
I do believe it is a good indicator for the effectiveness of a therapy after a significant amount of days.

DanEm

"If life hands you lemons, make lemonade! Words to live by, especially when you keep in mind that the only way to make them into lemonade is to squeeze the hell out of them."
Post Reply Post Reply
#24
RE: Oscar sessions seem wrong
So if I look at Jan 30 on your graph, I am seeing the AHI for the period of Dec 22 - Jan 30, right? Each day is the AHI of the beginning to that date. I spot checked and your graph does agree with the Statistics page when I set a date range.

I don't know whether I would find that is a useful way to look at the data. Usually it is only relatively recent data that is of interest. If you now have a string of AHI 0.0 days, the graph will only drop slowly. I leave that interpretation to you.

UPDATE: when I look for trends, I usually look at the Statistics page set in Monthly mode. That lets me scan a value, like AHI or its components, for the last 12 months.
Useful links
Download OSCAR (current version is 1.4.0)
Best way to organize charts
How to attach charts to your post

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.
Post Reply Post Reply






Donate to Apnea Board  
#25
RE: Oscar sessions seem wrong
I have build my progressive AHI from the start of my therapy since it was not that long ago.

If you want to see a trend, you need more than a few points on a curve.

Once you have a trend, you don't need all the back log.

Finally, the absolute values at any given moment is one information but not to helpful to evaluate if you are doing it right.

As I said, the important portions of my curve are those showing a decrease in the slope.
Of course you can consider the AHI values at zero and conclude the same.
My curve shows me I was doing good between Jan 3 and 10 regardless I had spikes in AHI Jan 4 and 5.

Anyway I wanted to know if my formulas were OK and it seems so.

Many thanks for your time bearing with me.


The last issue I have for now is the way Oscar screws up data when exporting sessions.
Although I think I have a work around, and can live with it.
Hopefully a fix will be find and implemented in the near future.

DanEm

"If life hands you lemons, make lemonade! Words to live by, especially when you keep in mind that the only way to make them into lemonade is to squeeze the hell out of them."
Post Reply Post Reply
#26
RE: Oscar sessions seem wrong
(02-01-2022, 01:53 PM)DanEm Wrote: The last issue I have for now is the way Oscar screws up data when exporting sessions.
Although I think I have a work around, and can live with it.
Hopefully a fix will be find and implemented in the near future.

That's next to look at.
Useful links
Download OSCAR (current version is 1.4.0)
Best way to organize charts
How to attach charts to your post

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.
Post Reply Post Reply
#27
RE: Oscar sessions seem wrong
How does the attached file look to you? Does the missing data appear to be present everywhere?

If it looks ok, we'll fix in the next release of OSCAR and I can give you a workaround.


Attached Files
.csv   OSCAR_A11 - DanEm_Sessions_2021-07-29_2022-01-29.csv (Size: 21.99 KB / Downloads: 2)
Useful links
Download OSCAR (current version is 1.4.0)
Best way to organize charts
How to attach charts to your post

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.
Post Reply Post Reply






Donate to Apnea Board  
#28
RE: Oscar sessions seem wrong
Quote:Does the missing data appear to be present everywhere?


Short answer is Yes, and then some.

Look at Excel file included.



Other glitch

  1. Opened Oscar and looked at last daily 22-02-01-A.png 
  2. Put SD card with latest data in laptop
  3. Clicked on Oscar/Welcome/CPAP Importer
  4. Nothing happened, no change in daily view
  5. Clicked on Oscar/File/Import CPAP CARD Data
  6. Nothing happened, no change in daily view
  7. Click on Oscar/Data/Advanced/Purge ALL Machine Data
  8. Clicked on Oscar/Welcome/CPAP Importer
  9. SD Card Data imported with new data 22-02-01-B.png
It happened before but did not think of reporting it.

DanEm

"If life hands you lemons, make lemonade! Words to live by, especially when you keep in mind that the only way to make them into lemonade is to squeeze the hell out of them."
Post Reply Post Reply
#29
RE: Oscar sessions seem wrong
(02-02-2022, 01:00 PM)DanEm Wrote: Short answer is Yes, and then some.

Workaround: OSCAR is exporting session data only for days that have been opened on the Daily page. So, to get a complete set of data, open the daily page for every day you want included on the report. You can just click once on the left arrow on the date setting, then just keep pressing the left arrow key.

Not pretty, I know, but we wil fix this.
Useful links
Download OSCAR (current version is 1.4.0)
Best way to organize charts
How to attach charts to your post

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.
Post Reply Post Reply
#30
RE: Oscar sessions seem wrong
(02-02-2022, 01:00 PM)DanEm Wrote:
  1. Opened Oscar and looked at last daily 22-02-01-A.png 
  2. Put SD card with latest data in laptop
  3. Clicked on Oscar/Welcome/CPAP Importer
  4. Nothing happened, no change in daily view
  5. Clicked on Oscar/File/Import CPAP CARD Data
  6. Nothing happened, no change in daily view

Please you expand on "Nothing happened". Did OSCAR present the dialog asking you to select your SD card, and then replacing it with one asking if it was ok to use the data it found? When it asked you if it was ok to use the place it found, was that the physical SD card or your copy?
Useful links
Download OSCAR (current version is 1.4.0)
Best way to organize charts
How to attach charts to your post

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.
Post Reply Post Reply






Donate to Apnea Board  


Possibly Related Threads...
Thread Author Replies Views Last Post
  Installing Oscar v 1.3.0 in a different C drive folder from version Oscar 1.2.0. rumtap 7 654 03-15-2022, 05:51 PM
Last Post: Crimson Nape
  Does time sessions show actual sleep. rylee1031 1 202 03-02-2022, 07:24 AM
Last Post: GuyScharf
  Oscar - Lost Data Sessions Herkness 10 458 02-07-2022, 12:05 PM
Last Post: Herkness
Question Used wrong SD card in OSCAR SideSleeper 7 322 01-31-2022, 02:34 PM
Last Post: SideSleeper
  AirSense 11 Stat Compliance Appears Wrong [solved] WIN4US 3 699 12-13-2021, 01:24 PM
Last Post: GuyScharf
  OSCAR 2.0 Problem and Questions [correction - OSCAR 1.2.0] rumtap 8 936 06-24-2021, 01:39 PM
Last Post: GuyScharf
  oscar question [popup reminder when closing OSCAR] hegel 5 525 06-21-2021, 03:54 PM
Last Post: Crimson Nape


New Posts   Today's Posts






About Apnea Board

Apnea Board is an educational web site designed to empower Sleep Apnea patients.