Concussion is a major problem in athletics: at least 300,000 sports-related concussions occur annually in the United States, according to estimates from the Center for Disease Control and Prevention. Unfortunately, many players don't realize when they've suffered a concussion, or they feel competitive pressures to ignore the symptoms and quickly return to play. Returning too soon can lead to further brain trauma--and eventually to early dementia and other signs of severe brain damage. Two high-profile cases came to light this year: neurologists say that repetitive concussion is the likely cause of brain damage in retired NFL defensive back Andre Waters, who committed suicide last year, and retired NFL linebacker Ted Johnson, who suffers from severe depression.

To address the problems, scientists are now trying to better understand concussion and find ways to quickly and objectively measure its severity. In one promising approach, researchers at New York University soon plan to test a handheld device to assess brain injury on the field.

"It would be a massive breakthrough to have a precise measure where you could wave a wand over an athlete and say, Yes, you have a concussion," says Chris Nowinski, a former college-football player and professional wrestler, now president of the Sport Legacy Institute, an organization based in Waltham, MA, that educates athletes about the danger of repetitive brain injuries.

Previous research has shown that concussion briefly changes the chemistry in the brain, generating a flurry of brain activity similar to a seizure. That activity leaves brain cells especially vulnerable. "The mechanism to deliver fuel to cells is damaged, and if the brain is subjected to another insult, the cells will die," says David Hovda, the director of the Neurotrauma Laboratory at the University of California, Los Angeles. Over time, damage accumulates, leaving lasting impairments in memory and attention.

Coaches and trainers routinely use crude memory tests to determine if a player can get back on the field. While these quick tests can detect major memory problems, they may miss more subtle cognitive dysfunction. "There is no clear protocol for when it's safe to send players back into games," says Nowinski. "Right now, we are without any technology to quickly--in under 20 minutes--and objectively diagnose mild traumatic brain injury."

An experimental handheld device that uses electroencephalogram (EEG) to read the brain's electrical activity might help. Under development by Roy John, director of the Brain Research Laboratories at New York University, and by Brainscope, a technology company based in Chesterfield, MO, the device is made up of an adhesive strip lined with six electrodes attached to a small computer. After a blow to the head, the strip is affixed to the athlete's forehead to record electrical activity, which is processed through a specialized algorithm and compared with a database of normal and abnormal electrical profiles. The processor then spits out a probability score predicting the likelihood of damage, says John.