More than two-thirds of high-school athletes who suffered concussions reported playing with symptoms, according to a study by the UW Schools of Public Health and Medicine.

The study, published in the American Journal of Sports Medicine, followed 778 male football and female soccer athletes through the fall 2012 season in 20 rural and urban high schools. The incidence of concussion was more than 10 percent among all athletes. Of those, 69 percent reported playing with concussive symptoms – such as headaches or dizziness – while 40 percent said their coach was not aware of their concussion.

These results were found despite Washington being the first state to pass legislation designed to protect youth athletes from returning to the field prematurely after suffering a concussion. Many of the athletes likely did not tell their coaches of their injuries, according to the study.

"More accurate and objective methods of identifying concussions are necessary, and new methods of reporting concussions, such as used [for this study] are needed to better understand the epidemiology of this important problem," wrote the authors, led by Dr. Frederick Rivara, professor of pediatrics and adjunct professor of epidemiology at the Harborview Injury Prevention and Research Center. They also cited the need for a change in the culture of a team and for new interventions aimed at improving the recognition and reporting of concussions.

Dr. Melissa Schiff, professor of epidemiology, was a co-author.