Quick story....
I had a mild concussion a couple of years back, was working at a job site and a steel support leg (a steel beam about a foot long) fell from the 3rd floor of the building site and landed on my head. Put a giant dent on the top of my hard hat and gave me a mild concussion. I had headaches, dizziness, blurred vision, and nausea for about 3 days and then they slowly started going away. After about a week, I was totally symptom free and the company doctor cleared me to go back to work. He said if I was not wearing my hard hat that I probably would not be here right now...............valuable lesson guys, wear yall's hard hats!!!