Hi Karl,
I was interested in your post since I have sleep apnea, so bad my wife says I stop breathing for minutes. I think I have got her worried I am not going to restart!!!!
I was curious since I had not realized that sleep apnea causes hypoxemia, so I did a search. When you Google "hypoxemea Parkinson's", I got over half a million references. It seems there is a definite link between PD and hypoxemia.
Best wishes
Ron