A traumatic brain injury can negatively impact a child's social life, according to a recent study.

Neuroscientists at Brigham Young University in Utah found that lingering injury in a specific region of the brain predicted the health of the children's social relationships.

"The thing that's hardest about brain injury is that someone can have significant difficulties but they still look OK," Shawn Gale, a neuropsychologist at Brigham Young University, said in a statement. "But they have a harder time remembering things and focusing on things as well and that affects the way they interact with other people. Since they look fine, people don't cut them as much slack as they ought to."

For the study, researchers studied a group of children three years after each had suffered a traumatic brain injury - most commonly from car accidents.

They compared the children's social lives and thinking skills with the thickness of the brain's outer layer in the frontal lobe. The brain measurements came from MRI scans and the social information was gathered from parents on a variety of dimensions, such as their children's participation in groups, number of friends and amount of time spent with friends.

Researchers also found that that physical injury and social withdrawal are connected through something called "cognitive proficiency." Cognitive proficiency is the combination of short-term memory and the brain's processing speed.

"In social interactions we need to process the content of what a person is saying in addition to simultaneously processing nonverbal cues," researcher Ashley Levan said in a statement. "We then have to hold that information in our working memory to be able to respond appropriately. If you disrupt working memory or processing speed it can result in difficulty with social interactions."

Separate studies on children with attention deficit hyperactivity disorder, which also affects the frontal lobes, show that therapy can improve working memory.

Further research is needed to determine if improvements in working memory could "treat" the social difficulties brought on by head injuries, researchers said.

"This is a preliminary study but we want to go into more of the details about why working memory and processing speed are associated with social functioning and how specific brain structures might be related to improve outcome," Gale said.