Hypoxia is nasty and extremely insidious.
I have experienced it in a chamber. After spending 2 mins off Oxygen trying to fill in a worksheet, I only managed to make a start on my name at the top.
The first two letters of my name.
Apart from a big grin, I wasnt aware of any problem.
And this paralysis occured after a rapid decompression from 8000 to only F250.