A simple bang on the head could affect your child forever

Some children may have memory and attention problems up to a year after a concussion, issues that can be tied to a lower quality of life and an increased risk of needing extra help in school, according to a U.S. study.

Concussion is by far the most common form of brain injury and has received increasing attention in the media, and millions of U.S. children get a concussion every year - but many don't go to the hospital, said Keith Yeates at Nationwide Children's Hospital in Ohio, who worked on the study.

"Out study pretty convincingly shows that the vast majority of kids do very well after a mild traumatic brain injury," Yeates said.

"The not-so-good news is that there is a small group of kids who have symptoms up to a year after their injury