How many fingers am I holding up?

Concussion science has come a long way since the bad old days when head injuries were diagnosed by finger-counting. But a new study finds that minor league hockey players have trouble identifying basic concussion symptoms and don't know when its safe to get back out on the ice after a knock to the head.

That's a sobering thought to anyone who watched Chicago Blackhawk Martin Havlat lying glassy-eyed on the ice after taking a major thump during one of last week's NHL playoff games. Okay, maybe not so many people watched that (except for Canadians, Chicagoans, and Detroiters like me), but here's the kicker: Two days later, Havlat was back in the game. Not for long, though: After taking a fresh hit, he made his way off the ice and didn't come back.

Concussions aren't harmless, especially they come in pairs. NOVA scienceNOW talked about the long-lasting and frustratingly nebulous symptoms of concussion in a story story that aired last year. Even more disturbing are results from the Boston University School of Medicine, where researchers are studying the brain tissue of deceased NFL players. Many of these players were in their 30s and 40s when they died, but their brains were mottled with the same tangles neuropathologists expect to see in elderly dementia patients.

Before they died, the players had reported crippling depression, memory problems, uncontrollable emotions, and debilitating headaches. Is this what we envision for our sports heroes' golden years?

-KB