Here's a scientific review of it's capabilities as compared to an EEG:
https://youtu.be/ogJ8uEUjW_8?t=664
For a long time, I was able to sleep w/ my CPAP in APAP mode (no EPR) with great results. For reference, I was diagnosed in 2014 w/ an AHI of 85 (severe) and my AHI on CPAP was around 3 or less most days. Gradually over many years I started to develop some memory issues and brain fog so I started my journey of optimizing my sleep via OSCAR and "working" (read: fighting) my local sleep doctor to give me access to more advanced therapies like bilevel & asv. After many terrible titrations and eventually failing CPAP due to aerophagia at high pressure levels, I was approved to start using bilevel. I tried for the better part of the last year to improve my sleep but could never get consistent results on bilevel, bought an ASV from craigslist to give it a go and was similarly disappointed.
Next, I started experiencing secondary insomnia and would wake up 2-4 times per night even though my Oscar data, sp02 etc. all looked good. As I continued to research, all roads lead me to wanting my own EEG to get as close to a sleep study as possible so I could tweak settings and get overnight feedback. While I searched I even tried a couple different sleep drugs like gabapentin & doxepin to try to get me to continuous sleep but knew that I didn't want to rely on drugs if I didn't have to.
That's when I went back to basics, bought a used Resmed Airsense 10 Autoset and started my own personal titration using the Apple Watch as my guide.
The first couple of nights I set the CPAP to APAP mode and used my old range of 9cmH20 - 16cmH20, EPR off, to see where my pressure averages were night over night. Then I took the 95% value (14cmH20), switched to CPAP mode and increased it by 1cmH20 every couple of nights until I saw less and less arousals on the watch the next morning. Finally, I started to introduce EPR slowly at the end and I'm currently sitting at 17cmH20 w/ EPR 3 and I only had one non-REM arousal over the past 3 nights, feel fantastic waking up and my symptoms are getting better!
It took a lot of bad nights of sleep to get here but it's been well worth it. If you'd like to try to duplicate my results, I'm also following good sleep hygiene protocols like:
1. Going to bed around the same time every night
2. Sleep in complete darkness w/ black out shades from Ikea
3. Sleep with my upper body elevated on a 7" foam wedge
4. Turn down the A/C to 67*, have the room fan running on the lowest setting and sleep under only a bedsheet
5. No eating or drinking within 3hrs of bedtime
Other things I learned:
1. Even 0.5mg of melatonin would give me arousals in REM
2. It took 500mg of Gabapentin to sedate me enough to sleep through the night
3. My humidity is set to Auto and tube temperature 70*F
4. 95% flow limit is 0.01 and 99.5% is 0.14
Here's what a pretty bad night looked like before:
This is while taking 600mg of Gabapentin right before getting into bed:
This is from last night w/ no drugs, CPAP mode, 17cmH20 + EPR 3
Oscar for last night:
So if you've been on cpap / bilevel / asv etc and are still feeling groggy / tired, following this protocol may help you like it did me. Good luck
For reference I'm using the Apple Watch SE from 2022 and I bought it from Best Buy in Open Box "Excellent Condition" for $185