I was searching around for a graph I'd found a couple of months ago that showed the difference in IQ (actually, the ability to communication intelligence) before and after brain function. Never found it- but did find this, which I thought was interesting:

What to Expect after TBI

And this next section of the site was particularly interesting. If I'm interpreting it correctly, it shows a correlation about where your brain was injured to what sort of symptoms you might expect. You can click on the map of the brain to see a brief overview of the functions of that part of the brain:

Brain Functions and Map