OSCAR and myAir

[BobinHI]

OSCAR and myAir seem to generally agree on AHI. But every now and then they differ significantly. Do they use different algorithms to calculate AHI?

[Narcil]

only thing that could really differ is the sessions shown bottom left in oscar. oscar by default will count all sessions for a day (between noon and midnight) unless you disable some, myair is slightly different i'm pretty sure it only shows the last session. i would disregard myair and disable some session in oscar if needed.

[Crimson Nape]

There can be 2 reasons for the variance. The first, is a reporting period difference. The Resmed will always reset to the default of a 30-day reporting period when it loses power. The second is least-significant bit truncation. I believe the Resmed uses 2 places to the right of the decimal, whereas OSCAR uses 8.
- Red

[BobinHI]

Thanks. The difference seemed more significant than a rounding error. But, oddly, it seemed that the ResMed myAir number for the night also differed from the AHI number shown on the screen on my ResMed 11. The AHI number on the screen seemed to match the OSCAR number, but the screen number and the OSCAR AHI numbers were different from that shown on the myAir iPhone App. I notice that today the App does not work at all, due to "Scheduled System Maintenance" so maybe the odd difference is a one-off thing associated with work on the App.

Thanks for the insights! I'll keep an eye on it and see if it happens again after ResMed completes its system maintenance.