How to tell if it's a concussion

Question: I get whacked in the head from time to time during soccer games. How can I tell if I have a concussion?

Answer: Although your first impulse may be to shake it off and get back in the game, it's important to stop and take stock of any symptoms. A blow to the head can cause your brain to collide with the hard inner surface of the skull, resulting in injury and possibly a concussion. (Hits to the body that trigger sudden brain movement can have the same effect.)

Contrary to popular belief, blacking out isn't the only sign of a concussion. More common -- and subtle -- warning signs include unsteadiness, dizziness, headache and problems with memory or concentration. If you experience any of these symptoms following the bang-up or in the days afterward, check in with your health care provider.

When in doubt, it's best to play it safe. If left untreated, concussions can lead to memory loss, brain damage -- or even death. And stay on the sidelines until you're fully healed and your doc has given you the green light. Returning to the field too soon and getting hurt again can trigger second-impact syndrome, dangerous swelling or bleeding in the brain. That's why the American Academy of Neurology recommends a qualified athletic trainer be present on the field or court during games and practices.

About our pro: Nancy Major, M.D., is a board-certified radiologist with a concentration in sports medicine. She is the chief of musculoskeletal radiology at the University of Pennsylvania.