just a small point to add-

an overnight oximetry may miss significant respiratory muscle weakness. As respiratory muscle weakness may lead to only a minor drop in the O2 sats, that would be considered within the normal range.

So it is important to check CO2 levels as well. Not all sleep labs are equipped to do so, and not all know how to interpret those results correctly! 99/100 sleep studies are done to assess sleep apnea (which is very common) and only very few for neuromuscular problems.

I can tell you my own experience- an excellent pulmonologist I consulted suggested by e-mail (due to geographical distance), that I should have a sleep study with CO2 measurements. my local pulmonologists sent me for that. the CO2 levels were increased, and I had a rapid breathing rate during the test, but the test was interpreted as normal because there was no accompanying drop in O2 saturation.

A few months later I had a similar test done again but this time by a neuromuscular respiratory physician. she also did a very extensive evaluation of my respiratory status. she showed me the results and told me that a less experienced clinician could have easily missed my significant fatigable respiratory muscle weakness because of the misleadingly normal baseline CO2 levels and near- normal overnite oximetry.

she was also the one that told me that my episodes of respiratory compromise are real and require respiratory support.