Pounded football players sustain brain changes.

• Position: Neurology

Some high school football players suffer undiagnosed changes in brain function and continue playing even though they are impaired, suggests a study by Purdue University, West Lafayette, Ind. "Our key finding is a previously undiscovered category of cognitive impairment," explains Thomas Talavage, an associate professor of biomedical engineering and electrical and computer engineering and co-director of the MRI facility.

The findings represent a dilemma because they suggest athletes may suffer a form of injury that is difficult to diagnose. "The problem is that the usual clinical signs of a head injury are not present," explains Larry Leverenz, clinical professor of health and kinesiology.

"There is no sign or symptom that would indicate a need to pull these players out of a practice or game, so they just keep getting hit."

The team of researchers screened and monitored high school players. "The athletes wore helmets equipped with six sensors called accelerometers, which relay data wirelessly to equipment on the sidelines during each play," notes Eric Nauman, associate professor of mechanical engineering.

Impact data from each player was compared with brain-imaging...