Regarding your (highlited) question about the chest sensor....Steerpike58 wrote: ↑Fri Aug 11, 2023 10:24 pmThanks for your detailed response, which makes a lot of sense. I especially appreciate your insight into the relative costs of different approaches, and why 'give them an APAP to try' makes some sense.
I have just one question about your comment above; I looked up the WatchPat device online, and it comes with a finger sensor and (optionally) a chest (heart?) monitor - a second wire. However, 'my' WatchPAT device didn't have the chest sensor, it only had the finger sensor. So - do you know what you get / don't get with/without the chest sensor component?
My general concern with all this is that I don't seem to have a baseline condition to measure against.
You can refer to the following two articles:
https://www.itamar-medical.com/wp-conte ... P_mail.pdf
https://www.sleepapnea.org/diagnosis/wa ... st-review/
The chest sensor detects snoring via a microphone and body movement via an accelerometer (similar to that of the accelerometer in your smart phone). It is clearly helpful to detect body position (supine, lateral, prone.
With regards to chest wall expansion take note of the following in the sleepApnea.org review:
Chestwall movement is best measured by a combination of EMG (Electromyography) and RIP (Respiratory Inductance Plethsmography) belts. These belts will actually measure the change in chest circumference brought about by inspiration/exhalation.
So, without the chest sensor, it would seem that you do not get, snoring detection or chestwall effort.
Apparently the the awake/asleep detection is based on the same technology used in smartwatches:
https://www.intex.in/blogs/blogs/sleep- ... p%20cycle.It primarily uses the gyroscope or accelerometer to track your movements and also detect which stage of the sleep cycle you are in. Some smartwatches use heart rate sensors to monitor your heart rate reading. Your heart rate lowers while sleeping also varies when you reach the different stages in the sleep cycle.
I suspect the finger probe (on your watchPat) did not have an accelerometer incorporated , it would seem that the watchPat analysis of sleep/awake is based on the heart rate.
Ultimately the WatchPat (and similar) are a cost compromise between the gold standard NPSG, where everything is directly measured, recorded and analyzed.