Spring sports are about to begin for young athletes, but a new study may raise concerns about their safety.
A study published this week in Brain: a Journal of Neurology found repeated hits to the head, not just concussions, can lead to chronic traumatic encephalopathy, or CTE, a debilitating brain disease commonly associated with former professional football players.
Researchers say the study shows the strongest evidence yet that CTE can develop in someone who's never had a concussion.
"We thought in the past, in order to get CTE, you have to have the repetitive concussions, but this study showed you don't have to have repetitive concussions to get CTE," said Dr. Khang Tran, chief medical officer at Medical City Plano.
Tran wasn't involved in the study but reviewed its findings.
"The brain is such an amazing organ. It can heal itself, but yet small injuries over time can lead to significant chronic damage, so it's just going to take time for us to understand the brain," Tran said.
The study took seven years and involved researchers from Boston University, the Cleveland Clinic, Harvard Medical School, Lawrence Livermore National Laboratory in California, Ben-Gurion University of the Negev in Israel and Oxford University.
The researchers analyzed four human brains from teenagers and young adults who had been exposed to mild head impact but died from another cause after the impact.
They found early evidence inside the brain consistent with signs of CTE, including abnormal accumulation of tau protein.
CTE is a neurodegenerative disease that can cause brain cell death, cognitive deficits and dementia.
The study's authors say about 20 percent of known cases of CTE had no record or report of concussion.
Tran says parents should use this data in their decision-making on youth sports for their children.
"I think it's just one data point that you need to have in order to make a decision whether your kid should play impact sports or not," he said. "But the study did show that quite significantly over time even sub-concussion impacts can lead to CTE."