It seems to me if the NERVE is damaged, it's DAMAGED, all the time, no matter what. I actually am fairly convinced my case is ETD, I can hear the eustachian tube pop and crackle at times, other side too but for some reason the valsalva maneuver made the left one worse. I'm asking otologist for MRI or any tests for eustachian tube dysfunction. Audiologist I saw was absolutely awful and there aren't any others around here that don't push hearing aids on you.