Hi Symbeline. Everyone is so different, if it were me I would say the tics you describe are from the PTSD. PTSD is essentially the body reacting to a stressor Ie, car accident---as if it was happening now even tho it isn't. Vertigo and dizzyness kinda go with panic for me.
By the way, have you checked with your general health practicioner to rule out any lingering physical problems from the accident. Any damage to middle or inner ear could also cause what you describe.
I hope you feel better soon.
Joined: 09-06-2008