I Was In A Serious Car Accident In 1978 ,

i was in a serious car accident in 1978 , i was struck by the drivers post of my car after a truck going 65 miles went through a stop sign and stuck my car side on, i was recently diagnosed as having shrinkage of my frontal lobes more than expected at my age. at the time of my accident there were no xrays or ct;s taken as it was a hit and run and no one wanted to get involved in the problems of the legal aspects so they sent me home from the hospital without any tests,
my suspision is that this accident has caused the shrinkage could this be the case?