My left arm goes numb at night while I'm sleeping. It's starting to get worse when it does that too.

My neuro checked my nerves with an EMG to see if I had carpal tunnel (had surgery on the right arm in 1990) and he said that I dont have carpal tunnel any more. (it can go away on it's own)

Said he thought that it was something related to the MS.

It could be that I sleep exclusively on my left side tho.

I have noticed that if I get overheated at night, my other arm will go numb too. I'll also have more numbness in the toes and lower legs too if I get really overheated.