I just saw this video on a post on Reddit that shows an elderly man playing piano while someone else plays a trumpet (coronet?).
There is no detail on the man playing the piano. We can only go by the video which looks like he suffers from dementia (to me at least).
My mom, who passed away a few months ago, had profound dementia. She never played an instrument so I never got to see if that part of memory survived.
Does it? Is muscle memory different than regular memory?