Concussion may be present without symptoms

WEST LAFAYETTE, Ind., Sept. 14 (UPI) -- Most doctors say if an athlete has no concussion symptoms there are no problems but U.S. researchers say there may be brain changes with no other symptoms.

Larry Leverenz, an expert in athletic training and a clinical professor of health and kinesiology at Purdue University in Indiana, says players in the study received 200-1,800 hits to the head in a single season, with two players receiving the maximum number.

Helmet-sensor data indicated impact forces to the head ranged from 20 Gs (gravitational constant) to more than 100 Gs.

"We are finding that there is actually a lot of change, even when you don't have symptoms," Leverenz says in a statement.

"The worst hit we've seen was almost 300 Gs," researcher Eric Nauman of Purdue University says.

A soccer player "heading" a ball experiences an impact of 20 to 50 Gs, Nauman says.

The findings could aid efforts to develop more sensitive and accurate methods for detecting cognitive impairment and concussions, and ways to reduce the risk and effects of strong jolts to the head, the researchers say. In addition, the study may help in more accurately characterizing and modeling cognitive deficits that result from head impacts, and in determining the cellular basis for cognitive deficits after single or repeated impacts, they say.