I wonder if it might be epilepsy. Sometimes the strangest things can trigger an epileptic seizure -- including a smell, a flash of light, a certain rhythm or frequency...
And although you say he did have something that was recognizable as a seizure, it's possible that he might be having more subtle seizures as well... episodes that cause him to feel pain or to be frightened, which could make him behave as you describe.
Whatever it is, it might not be something that an ordinary vet can easily diagnose. But since I see you're right here in DFW, I know there are lots of specialists around here. Are you aware of the veterinary referral center over on Trinity Mills Road?
And although you say he did have something that was recognizable as a seizure, it's possible that he might be having more subtle seizures as well... episodes that cause him to feel pain or to be frightened, which could make him behave as you describe.
Whatever it is, it might not be something that an ordinary vet can easily diagnose. But since I see you're right here in DFW, I know there are lots of specialists around here. Are you aware of the veterinary referral center over on Trinity Mills Road?