Wear your bike helmet.

Interesting article on TBI at Dirt Rag.  First-hand experience.

Beyond saying that I won't even test bike adjustments riding around the yard without wearing a helmet, I won't belabor the subject. The entire article can be a bit much to read, so I'll summarize with this quote from it:

Untreatable

I talked to a specialist, who told me there’s little that can be done to improve my situation. For the most part, what I’ve been doing to stay on top of things keeps me straight. I still forget to do certain things. ...  I don’t feel as intelligent as I was prior to the accident. Oftentimes I can’t get my thoughts out of my head—if I can remember what it is I wanted to say to begin with. While I’m not sure that I’ll ever fully recover from my injury, I’m positive that my situation could have been prevented if I had simply worn a helmet. Even though it was intended to be a brief ride up and down the street to check operation of my bike, it turned into so much more.

Wear your bike helmet.  I'll post something happy tomorrow.