In regards to your "permanent" question...

I've read that some neuropsychologists think that significant improvements can be made for up to two years after a brain injury.

My neurologist recently told me that it's rare to see improvement after 12-18 months, but I wonder if that's "old school" thinking about the matter. New research is demonstrating that neuroplasticity continues throughout life - what that means for the survivors of concussions, I'm not exactly sure, but I try to find as much hope in it as I can.

And Space Cadet posted a blog here that was written by a woman who says it took her 4-5 years to feel close to normal again after sustaining a concussion. I wonder if that just means she got used to feeling the way she did and confused it for her previous level of functioning, but it sounds hopeful too.