Athletes with a history of concussions may exhibit subtle and chronic brain changes

A new study suggests that athletes with a history of concussion may have more brain damage from subsequent concussion, especially in the mid-brain regions that are more likely to be damaged, compared to athletes without a history of concussion. concussion.

The research is published in the August 25, 2021 online issue of Neurology^®, the medical journal of the American Academy of Neurology. The athletes participated in sports such as football, volleyball and soccer.

“We know that concussions can have long-term effects on the brain that last beyond a doctor’s permission to resume gambling, ”said study author Tom A. Schweizer, PhD , from St. Michael’s Hospital in Toronto, Canada.

However, it is not known to what extent the effects of repeated concussions can be detected in otherwise healthy young adults. We found that although there was no difference in symptoms or in recovery time, athletes with a history of concussion exhibited subtle and chronic changes in their brains. “

Tom A. Schweizer, PhD, lead study author, St. Michael’s Hospital

This study focused on changes in two areas of the middle of the brain that are particularly vulnerable to concussions. The researchers focused on blood flow in the cingulate cortex and white matter microstructure in the corpus callosum.

Changes in blood flow and microstructure that show on brain scans may indicate an underlying brain injury. The cingulate cortex is a layer of gray matter that coordinates sensory and motor skills. Below is the corpus callosum, a broad band of nerve fibers connecting the two hemispheres of the brain.

The study involved 228 athletes with an average age of 20, including 61 with a recent concussion and 167 without. In the first group, 36 had a history of concussions. In the second group, 73 had a history of concussion.

Researchers performed up to five brain scans of each recently concussed athlete, from the time of the injury until a year after returning to play.

The researchers found that one year after a recent concussion, athletes with a history of concussion had a more marked drop in blood flow to an area of ​​the cingulate compared to those without a history of concussion. People with a history of concussion had an average cerebral blood flow of 40 milliliters (mL) per minute, per 100 grams (g) of brain tissue. People without a history of concussion had an average cerebral blood flow of 53 ml per minute, per 100 g of brain tissue.

In athletes with a history of concussion, in the weeks following a new concussion, researchers also found microstructural changes in a region of the brain called the splenium, which is part of the corpus callosum.

“Our results suggest that an athlete with a history of concussion should be monitored closely, as these subtle brain changes can be made worse by repeated injuries,” said Schweizer. “In addition, our results should raise concerns about the cumulative effects of repeated head injuries later in life.”

One limitation of the study is that athletes reported their own history of concussions and could be inaccurate. More research is needed to track athletes over time.