Coaches and trainers generally rely on an athlete's own description of symptoms such as dizziness, headache and visual disturbances to determine if he or she has had a concussion, Dr. Mark R. Lovell of the University of Pittsburgh Medical Center, Philadelphia, and colleagues note in the American Journal of Sports Medicine.

However, they add, athletes may often minimize or deny their own symptoms in order to stay in the game or on the team.

The Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) system is a series of tests intended to identify the decline in memory that occurs after concussion and can last for as long as a week, and may offer a more objective way to diagnose concussion in young athletes, Lovell and his team explain. The assessment includes a 20-minute series of tests of verbal and visual memory, reaction time, and visual motor processing speed.

To evaluate the effectiveness of ImPACT in helping to spot concussions, the researchers had athletes complete the test two days after a suspected concussion, and compared the findings with a diagnosis made immediately after injury by a doctor or certified athletic trainer.

All 122 athletes had completed the computer testing before being injured, so the researchers were able to compare their scores before and after the test.

Also, 70 athletes who had not had recent concussions served as a comparison group. They had been tested once with ImPACT and then again one week later.

Overall, 64 percent of the athletes reported an increase in symptoms after the suspected concussion, while 83 percent had abnormal results on the ImPACT test.

"This study demonstrates that even athletes who report being symptom free may continue to exhibit neurocognitive deficits that they are either unaware of or are failing to report," Lovell and his colleagues write. "Our data suggest that if neurocognitive testing is unavailable, the treating physician should be cautious in returning athletes to play based on their self-report of symptoms."

The researchers conclude that the ImPACT test offers "added value" to the "gold standard" of diagnosis by medical doctors or certified athletic trainers on the field.

Lovell and another study author are shareholders in ImPACT Applications, the company that sells the test.

SOURCE: American Journal of Sports Medicine, October 2006.