Clunk! Did my kid just have a concussion?

"Shake it off and get back in there" was the old mantra when a kid or teen athlete got clocked during practice or in a game. That's changing—thanks to a growing awareness of the long-term effects of concussions on the brains of college and adult athletes. Shockingly, experts still know little about what happens when a kid or teen's brain smashes to a stop against the hard wall of their inner skull.

But two things are clear. First, your kid's brain needs plenty of time to heal after a concussion. A second head injury on the heels of the first can cause serious, long-term problems. Second, parents and coaches don't always recognize the signs of a concussion when it happens—meaning kids don't always get the diagnosis and rest they need.

One recent Canadian study found that parents of young hockey players (a sport where concussions are fairly common) didn't always know the tell-tale signs of this serious head injury. (Moms knew a little more than Dads, but nobody was 100 percent correct.) And a study of Michigan parents found that many didn't realize their children were experiencing post-concussion symptoms that needed medical attention.

Would you? The question is not just for parents and guardians of kids who play sports. Of the 144,000 teens and kids who show up in American emergency rooms each year with a concussion, two-thirds weren't playing organized sports. Kids clunk their heads falling off chairs, riding their bikes into telephone poles, getting hit in the head while rough-housing. Tell-tale signs go far beyond blacking out or seeing cartoon-character stars. Concussion symptoms can also include:

You could print this list and keep it in your wallet. Or you could resolve to take your kid to the emergency room or to the doctor, pronto, after any bump or blow to the head that's forceful or leaves them not quite themselves. Several area medical centers offer fast concussion evaluation via a system called ImPACT (Immediate Post-Concussion Assessment and Cognitive Testing). These include St. Chris Specialty Pediatrics at Bucks County, in Yardley; Philadelphia Concussion Center at Magee Rehabilitation Hospital in Philadelphia; Children's Hospital of Philadelphia; the Temple University Athletic Concussion & Neurotrauma Center. Many high schools also utilize the test. For a complete list, go to http://impacttest.com/ .

Tell us what you think. Has your child ever had a concussion? How long did it take for her or him to fully recover? Has risk of head injury swayed your choice of sports for your kids?