Athletes with a history of concussion may show more serious brain injury from a later concussion, new research has revealed.
In comparison to athletes with no history of concussion, those who have sustained head injuries previously may show greater impact, particularly in middle regions of the brain that are more susceptible to damage.
Athletes with a history of concussion should be monitored more closely, the research team said in light of their findings.
“We know concussions may have long-term effects on the brain that last beyond getting a doctor’s clearance to return to play,” said study author Dr Tom A. Schweizer, of St. Michael’s Hospital in Toronto, Canada.
“It is unclear, however, to what extent the effects of repeated concussion can be detected among young, otherwise healthy adults.
“We found even though there was no difference in symptoms or the amount of recovery time, athletes with a history of concussion showed subtle and chronic changes in their brains.”
The study focused on changes within two areas in the middle of the brain that are especially vulnerable to concussion. Changes in blood flow and microstructure that show up on brain scans can indicate underlying brain injury.
The study focused on 228 athletes with an average age of 20, including 61 with a recent concussion and 167 without.
Within the first group, 36 had a history of concussions; in the second group, 73 had a history of concussions.
Researchers took up to five brain scans of each recently concussed athlete, from time of injury to one year after returning to play.
Researchers found that one year after a recent concussion, athletes with a history of concussion had sharper declines in blood flow within one area of the cingulate compared to those without a history of concussions.
Those with a history of concussion had an average cerebral blood flow of 40ml per minute, per 100g of brain tissue.
For those without a history of concussion, they had an average cerebral blood flow of 53ml per minute, per 100g of brain tissue.
In athletes with a history of concussion, in the weeks after a new concussion, researchers also found microstructural changes in the splenium area of the brain.
“Our findings suggest that an athlete with a history of concussion should be watched closely, as these subtle brain changes may be worsened by repeated injury,” said Dr Schweizer.
“Additionally, our results should raise concern about the cumulative effects of repeated head injuries later in life.”
