James,

Did you ever get a vestibular assessment?

Just as a going over a pothole with a bicycle is not a concussive event, most of the triggering events suffered by people with prior concussions/TBI are not concussive.

They can be and often are only whiplash events that only requires a 4.5 G movement. A concussion requires 60 to 90 Gs of movement.

They can also be vestibular events that require a vestibular therapist to help the crystals get properly positioned in the inner ear.