Research is underway in finding a quick, easy and simple test to identify a concussion. The most advanced test is a blood test using proteins as markers for a concussion, and is in Phase III of research with the US Military.
Tom Avril of the Philadelphia Inquirer wrote a great piece on this.
From a scientific perspective, no one really knows. Physicians can see when someone’s outward symptoms have returned to normal, as most do within a few weeks. But there is no lab test to measure internal damage from a concussion and no medicine to treat it.
“Absolutely nobody knows when it’s safe to go back in,” said Douglas H. Smith, director of the University of Pennsylvania’s Center for Brain Injury and Repair. “If anyone says one week is good, three weeks is good, they’re not basing it on facts.”
There is great information in that article I encourage you to read the entire thing. Here are some more excerpts;
They want to know if there has been subtle damage inside brain cells – the sort of thing that might lead to chronic problems years later.
The quest has taken on new urgency with the prevalence of soldiers who suffer head injuries from the jolt of an explosion, experiencing cognitive deficits despite the lack of external wounds. Concern over the issue has filtered through to civilians as well, from professional athletes down to neighborhood leagues.
“Concussion is not like an ACL injury. Everybody’s knee is essentially the same. We know what it does, we know what it should do,” allowing for a standard treatment protocol, Kutcher said. “Brains are way too diverse for that.”
Then there’s the problem that concussions have historically been underreported, because of the old attitude that athletes should shake it off and get back on the field – an approach that neurologists say is dangerous. Estimates of the number of concussions vary widely, but tend to place it well above one million each year.