My daughters like this. I'm keeping a close eye on it. Her dad has ADHD and she displays some of the behaviours, although she can't be formally diagnosed till she is 8.
I heard/read a theory that people predisposed to tinnitus are hyper-predictors of sound. in other words, the brain is hyperactive in anticipating the next sound. I think it might have been on the tinnitus talk podcast but I don't remember which episode.