Update:
I believe I’ve figured out the cause of the hearing and vertigo issues I mentioned in previous posts.
It seems like the simple answer is a weak immune system. It appears that through years of ear problems and stress, the symptoms of temporary hearing loss and vertigo come whenever I have had some kind of mild illness, such as a cold, cough or flu. When I think about each time it’s happened, I usually had these symptoms in the days before.
While I haven’t figured out a cure as such, I at least know that it probably isn’t a long-term, permanent problem as I feared.