SleepyHead: differing AHIs on "summary only" nights

OK, I can see the machine reported AHI from the hidden clinical menu and it does match the AHI that SleepyHead reports. So I'm not sure where the low number of nights without the SD card inserted came from.

(My configuration is in Finnish and there is one item labeled "Essentials" but that's only on/off option. It's on. But I can see the AHI by entering the clinical menu and going to the sleep report so that doesn't matter for now.)

jajvirta wrote:OK, I can see the machine reported AHI from the hidden clinical menu and it does match the AHI that SleepyHead reports. So I'm not sure where the low number of nights without the SD card inserted came from.

Is it the same for both conditions, with and without the card?

Jay Aitchsee wrote:Is it the same for both conditions, with and without the card?

Haven't yet tested what the machine reports on its display when the card is not in. Maybe I'll do that too.

Yes, test the machine results against Sleepyhead without the card.

OK, so I finally went with a night without the SD card inserted and had a look at the AHI reported by the clinical menu on Airsense S10. The clinical menu reported 1.9 AHI. Then inserted the SD card and imported the data into SleepyHead and it reports the AHI as 0.29.

So it appears that the summary data that is written on the SD card is either not the what the machine itself reports or SleepyHead makes a wrong interpretation of the summary only data.

Or, the date and time on the CPAP is not the same and the end of day doesn't match so you are not comparing the same data ranges.

I think it's in the way the calculations are performed: Generally, I think Sleepyhead calculates the indexes independently, from the detailed data, and without the detailed data of the card, SleepyHead can not make the calculation. ResMed does the calculation and saves it to the machine summary data.
Without the detailed data, SH must present a result taken from the summary data, but which one(s)? There are four components actually, OI, CI, UI and HI which ResMed/ResScan tallies for the reported AHI. Perhaps without the card, SH reports an incomplete statistic. My AHI reported by SleepyHead without the card seems to always to be less than that of the corresponding day as reported by ResScan.
On days with the card and detailed data, the two reports are close, with either being higher or lower.
So, from the results of my limited number of missed detailed data days, I would guess that SleepyHead is unable to accurately calculate the AHI if the detailed data is missing, which to me doesn't seem too surprising.

Jay Aitchsee wrote:So, from the results of my limited number of missed detailed data days, I would guess that SleepyHead is unable to accurately calculate the AHI if the detailed data is missing, which to me doesn't seem too surprising.

Yeah, this was my conclusion too.

I was mostly concerned that SleepyHead was badly off for most nights, but that obviously isn't the case.