Low AHI - Still Poor Sleep - Apple Watch vs Oscar?

[Jakeb24]

Hey Everyone, 

Been on therapy for almost 3 months now. While I feel like I have improved a little bit. I am still struggling with getting good restful sleep.

I like to compare Oscar to my watch data and while OSCAR reports rather low AHI, my watch reports my many wake ups with long awake times. 

Just wondering if I am missing something here or maybe looking too far into this? Any insight is appreciated! 

 - I also average about 6-7 hours of usage a night, these last 3 days I have been taking the mask off more in my sleep. But my Apple watch data is similar even when I get more therapy hours.

Thanks!

[PeaceLoveAndPizza]

Interesting as I do the same thing comparing my Apple Watch to the OSCAR charts. Glad to know I am not alone in the practice. I get similar spikes in the AW compared to OSCAR, but have not dug into it deeply. I know that even when then AW shows an “awake” spike it may be just for a few seconds, but because of the resolution it may look longer than what was detected.

Do you actually get out of bed or sit up? Otherwise the AW may be recording excessive arm movement as being awake. Have you been tested for PLMS/PLMD? You can read more about it here:

https://www.apneaboard.com/wiki/index.ph...der_(PLMD)

https://www.ncbi.nlm.nih.gov/books/NBK560727/

You can read about general sleep hygiene here:

https://www.apneaboard.com/wiki/index.ph...ep_hygiene

Your pressure range looks to be fine, but I would give it a try with EPR 2 instead of 3. It may help with the central apnoea’s being reported. As you are already into your third month of usage, I do not think it is still treatment emergent CA, so a bit less EPR, flatter pillow, and possible a soft cervical collar, may help.

[Jakeb24]

Interesting as I do the same thing comparing my Apple Watch to the OSCAR charts. Glad to know I am not alone in the practice. I get similar spikes in the AW compared to OSCAR, but have not dug into it deeply. I know that even when then AW shows an “awake” spike it may be just for a few seconds, but because of the resolution it may look longer than what was detected.

Do you actually get out of bed or sit up? Otherwise the AW may be recording excessive arm movement as being awake. Have you been tested for PLMS/PLMD? You can read more about it here:

https://www.apneaboard.com/wiki/index.ph...der_(PLMD)

https://www.ncbi.nlm.nih.gov/books/NBK560727/

You can read about general sleep hygiene here:

https://www.apneaboard.com/wiki/index.ph...ep_hygiene

Your pressure range looks to be fine, but I would give it a try with EPR 2 instead of 3. It may help with the central apnoea’s being reported. As you are already into your third month of usage, I do not think it is still treatment emergent CA, so a bit less EPR, flatter pillow, and possible a soft cervical collar, may help.

Hey!

Thanks for the tips, gave it a shot last night with a collar, was laying flat on my back since that felt most comfortable so maybe that caused my AHI to go up? 

Attached my data, funny that apple watch reports more sleep but oscar reports one of my highest AHI's.

[PeaceLoveAndPizza]

What we are shooting for is a quality nights sleep. Having some centrals is not a big deal as long as they don’t wake you up or impact sleep quality.

Sleeping on your back is the likeliest cause. Many have their highest AHI whilst sleeping supine. 

Interestingly your flow limitations did change between EPR 3 and EPR 2, from a median of 0.01 to 0.03. It is a limited study of a single night, but directionally it makes sense. You could try an EPR of 1, but it would likely result in even higher FL’s and AHI. Would be interesting to see if you ever feel like testing the hypothesis.

For now, I suggest staying with the original numbers of 7-11 EPR 3. You could try an 8-12 EPR 3 as well just to see what happens. Continue with the collar for a few nights and let’s see how things look and how you feel.

And don’t sleep on your back if you can help it…

[staceyburke]

Let me throw something out here.  We look at Oa and H events to find positional apnea.  If the Oa or H events are clustered together it is a very likely sign that a person has positional apnea.  You do not have this showing up in your charts BUT most of your central are grouped together.  The machine is not always correct in telling if centrals are real central.  All it does is shot pulses of air while the apnea is happening and IF it does not detect an obstruction it is called a central.  The only real way of knowing if they are centrals is to be hooked up in a sleep lab with all the wires and belts to see if there is attempt to breath or not.  The cpap machine does not have that type of sensing equipment.
 
So let me give you a little bit about positional apnea.  Getting rid of as many as you can will lower your AHI.  Positional apnea can NOT be controlled by pressure changes.  You have to find out what position you are getting into and cutting off your own airway.  Have you changed your sleep position?  Sleeping on your back?  Using more (or new) pillows?  These things can cause positional apnea by chin dropping to your sternum and cutting your airway.  Think of it of a kinked hose – nothing can get through – you have to unkink the hose… I have a link to collars in my signature if you want to try using one.  Please take a look at the link.
 
Again, you do NOT show typical positional apnea BUT see if this may apply to you

[Sleepster]

I don't understand this discussion. The apple watch has an accelerometer in it, so it detects when your arm is moving, and uses some algorithm to determine if you were awake. But the CPAP machine only knows if it's on or off. As long as the machine is on and you're masked up, the machine is going to report that you're "asleep". That's all it can do.

[PeaceLoveAndPizza]

Sleepster, apologies for it being a bit scattered. The original question was related to correlation between Apple Watch sleep states and OSCAR. 

Completely agree with the AW awake states being on the high side. Maybe something there in OSCAR, maybe not. Nothing jumps out to me.

[Sleepster]

The original question was related to correlation between Apple Watch sleep states and OSCAR. 

That's what I mean. How can there be a correlation? AW uses an accelerometer and OSCAR uses the on/off button pressed by the sleeper.

[PeaceLoveAndPizza]

I was thinking the same, but after more research it turns out that the AW uses more than a simple accelerometer to determine awake vs sleep states. It is actually a 3-axis accelerometer that is quite sensitive to small movements.

Details can be found here: Estimating Sleep Stages from Apple Watch

Scientific validation from a post doc student is here: Apple Watch Series 9 : Full SCIENTIFIC Review (youtube.com)

Whether any of that correlate to OSCAR data remains to be seen. It would be an interesting research topic.

[Sleepster]

I was thinking the same, but after more research it turns out that the AW uses more than a simple accelerometer to determine awake vs sleep states. It is actually a 3-axis accelerometer that is quite sensitive to small movements.

That's what I meant by accelerometer. AFAIK the accelerometers used in all kinds of devices, such as my phone, are 3-axis accelerometers. They need three axes to determine both the magnitude and direction of the acceleration.

So, the premise still holds. The CPAP machine has no way of determining if you're awake or asleep, all it knows is whether or not the user is using it.