The company I worked for over 10 years ago, CardioDynamics*, manufactured an impedance cardiography (ICG) diagnostic device. The technology behind ICG and the Onera Bioimpedance Patch to Detect Sleep Apnea is called thoracic electrical bioimpedance (TEB).
It's no surprise that Onera has leveraged research on monitoring lung resistivity with this technology (e.g. here and here) and is applying AI for automated respiratory event detection. Since electrode placement is important for reliable data acquisition, the patch is a good design choice, but it doesn't look like it would be that comfortable to wear to sleep.
Another review, Wearable Patch Uses Machine Learning to Detect Sleep Apnea, notes that assessing sleep apnea requires additional physiological signals to be monitored and that more work needs to be done to combine this technology with these other signals.
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*Purchased by SonoSite in 2009. SonoSite has since stopped manufacturing the BioZ DX.
