How To Diagnose Brain Damage?

I got in accident as a child I can't remember what year. Car accident. Anyway i fell through the windshield and had to get stitches near my left eyebrow. Could that have caused any type of brain damage?? I was really young and I don't think I EVER got a cat scan so I have no idea if anything could have gotten damaged. I would just like to know what that part of the brain controls? Thanks