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Japanese sleep test vs. Lofta/WatchPAT discrepancy + flow chart morphology analysis?
Japanese sleep test vs. Lofta/WatchPAT discrepancy + flow chart morphology analysis?
Some Background Info:
I began APAP (ResMed Airsense 10) therapy in late-September (so it's been about 3 months). Sleeping with the mask, etc. doesn't really seem to bother me and I've been very consistent in my use of the machine.

Subjectively though I'm not sure if I actually feel better or not. (I suppose I could probably test this by sleeping without the APAP.) Also, my sleep duration is probably still quite lacking which could account for not feeling much of a change.

For context, I'm currently living in Japan (not Tokyo). I was able to locate a doctor who at the very least tests for sleep apnea, provides APAP, and monitors the progress of the treatment. However, I get the sense that sleep medicine and treatment for sleep-disordered breathing stuff is just less advanced here than it is back in America.

Take-Home Test #1 (Japanese doctor)
Anyway, via this Japanese doctor, I took a take-home sleep study (device = Fukuda Denshi, PulSleep LS-140). The results of this test showed about 8AHI per hour, or about 60AHI total for the total 7.5ish hours I slept that night. This was enough to qualify for a diagnosis of mild sleep apnea here in Japan which meant I could rent (under Japan's national healthcare system, typical protocol seems to be you rent the CPAP) an APAP, although at a rather steep monthly fee because the diagnosis was only mild (not reaching moderate/severe).

Take-Home Test #2 (Lofta/WatchPAT One)
Trying to pursue various avenues of treatment simultaneously to try to get a CPAP ASAP, I had also ordered a take-home sleep test via Lofta (they use the one-time use/disposable WatchPAT One which can transmit the test data remotely, i.e. you don't have to ship it back to them to get the results, which was perfect since I'm living abroad), which I had my family ship to me, since Lofta didn't appear to ship to Japan.

In early-October (after having started APAP treatment a little under 2 weeks earlier), I took this Lofta at-home sleep test. I did NOT use the APAP the night I took the test. The results were a little puzzling. It showed only 0.3AHI/hour and 2AHI during the whole night (only ended up sleeping about 5 hours). On the other hand, it showed an RDI of 12/hour for a total of 64RDI for the 5ish hours I had slept.

Point of Confusion #1:
So in comparison to the first test which showed 8AHI/hour, this second test showed basically 0AHI/hour. Again, I did NOT use the APAP the night I took the 2nd test, so I entirely expected to see a similar-ish AHI of 8AHI/hour. I suppose there could have been variability in terms of my sleep? The testing devices were also different so that could also maybe account for the difference in results?

Point of Confusion/Uncertainty #2:
The Lofta test while showing effectively 0AHI, showed 12RDI/hour. Since the AHI was 0, that would make the whole of the RDI composed of RERA. So basically 12RERA/hour.

The 1st test I took either didn't measure RERA (appears nowhere on the results sheet) or if it had detected RERA, my Japanese sleep doctor didn't feel it necessary to tell me that it had (he does seem mostly concerned with AHI).

So if the Lofta take-home test was correct, the fact that my AHI shows as near 0 in OSCAR and on the monthly AirView reports I get from my Japanese doctor would be nothing to celebrate since it now seems possible that my AHI was 0 to begin with.

My new concern however regards the RERA detected by the Lofta test. The APAP and OSCAR don't appear to be detecting RERA as you can tell by looking at the “Event Flags” tab, but for some reason I'm just somewhat suspicious that the ResMed machine/OSCAR have trouble detecting RERA.

So my main concern is whether or not these RERA detected by the Lofta sleep test are being effectively treated by the APAP.
(I suppose the best way to find out would be to order another WatchPAT kit and use it while using the APAP, but at about $200 a pop and with the hassle of having to have family ship it to me internationally... hmm I might actually end up doing this.)

Anyway, any thoughts about any of this would be appreciated.


Request for Flow Rate analysis:

I found this graph showing various flow chart patterns somewhere and it was interesting to me that if there was an irregularity in breathing pattern that the nature/cause of that irregularity could be detected by looking at the shape of the graph.

The attached zoomed-in Flow Rate chart is of a random 2 minutes I chose which didn't seem to be too close to me either falling asleep or waking up.
The pattern of “peaks and valleys” seems relatively uniform, but when I compare it to the smoothness/roundedness of the “Normal Flow Morphology” flow chart … well it obviously doesn't quite look like that.

I'm wondering if anyone can tell me whether my Flow Rate chart indicates a “normal” breathing pattern or more generally what the shape of my Flow Rate chart can tell me about my breathing pattern.

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RE: Japanese sleep test vs. Lofta/WatchPAT discrepancy + flow chart morphology analysis?
Very interesting. If I might, can you answer a couple of questions? 
Did either the "Japan-based" or the Lofta sleep study involve the use of a nasal cannula (to actually measure the air flows)? Both or neither, or one did and the other did not?

As far as I can tell, Lofta is a DME (durable medical equiptment provider) and is not a a sleep doctor/physician.
Further, apparently there are a couple of different "tools" that are all generically called "WatchPat".

The two graphics you provided can not be compared in their present form. The first one (morphology) displays  breath-by-breath patterns, the second (from OSCAR) displays the entire breathing for the whole of the session. To draw any comparison, you need to expand the OSCAR flow chart so that it would display breath-by-breath shapes. That can be a bit tricky, because you first want to see (over the whole night) what pattern is representative of your "normal" asleep breathing. Then contrast that representative breath shapes with breath shapes preceding what your machine has evaluated as "events" or flow limitations. 

And by the way, did your Japanese doctor/technician prescribe your 4-6 APAP settings. IMO that is just barely theraputic, if your AHI is truly in the 0.15 area, with that level of therapy, I'd seriously wonder if you need treatment for OSA at all.

Have a  Wink day
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