Female.

Age of onset: 24, right after a bad bike crash

I have not had any issues with bumping my head (which I have bumped it plenty of times since the bike crash, as most people do). Only have had issues with sudden change in speed of head movement (falls, hitting very large potholes in the car, etc.)

Also, all linear motion feels exaggerated compared to what I would expect to feel. Walking used to feel like a violent rollercoaster ride when this symptoms was at it's worst.