Ear infection seems likely. But recently one of my mice had a seizure. She was bitten on her rump side quite severely, then it started to heal and do very well, then it cracked open and bled then started to have the seizur, having a seizure every minute or two, having about 10 in the hour. But is fine. Also when I put meds on her rump to soothe her pains,the smells, (very very smelly) one made her very limp.

So I figured extreme pain or smells could trigger these or other medicals reason.

Poor rat