Department of Emergency Medicine

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Title: Acute and Chronic Effects of Multiple Concussions

Category: Neurology

Keywords: Sport concussion, brain injury (PubMed Search)

Posted: 8/28/2021 by Brian Corwell, MD
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Study Question: A recent study investigated whether a history of concussion caused greater disturbances in cerebral blood flow and cerebral white matter after subsequent concussions.

Background: Researchers used changes in blood flow in the cingulate cortex and white matter microstructure in the corpus callosum as evidence of underlying brain injury.

Population: 228 athletes with an average age of 20. Divided into 2 groups, recent and non-recent concussion.

61 athletes had a recent (uncomplicated) concussion and 167 did not. Within the first group, 36 had a history of concussion. Within the second group, 73 had a history of concussion.

Note: researchers used “self-reported” history of concussion in study.

Intervention: Researchers took up to 5 MRI scans of each recently concussed athlete. This encompassed the acute phase of injury (1 to 7 days post-injury), the subacute phase (8 to 14 days), medical clearance to return to sport, one month post return and one year post return.

The sport concussion assessment tool (SCAT) was also used to evaluate effects of history of concussion on symptoms, cognition and balance.

Results: One year after a recent concussion, those athletes with a history of concussion had sharper declines in blood flow within one area of the cingulate cortex compared to those without a history of prior concussions.

Athletes with a history of concussion had an average cerebral blood flow of 40 mL per minute, per 100 grams of brain tissue.

Athletes without a history of concussion had an average cerebral blood flow of 53 mL per minute, per 100g of brain tissue.

In the weeks following concussion, those athletes with a prior history of concussion had microstructural changes in the corpus callosum.

Effects were seen in the absence of differences in SCAT domains or time to return to sport.

Conclusion: Athletes with a history of concussion experience identifiable injury to their brains as evidenced by changes in blow flow and white matter microstructure. Athletes “cleared” for return to play following concussion may be at greater risk of subtle patterns of brain injury versus their peers.

References

Acute and Chronic Effects of Multiple Concussions on Midline Brain Structures. Churchill et al. Neurology Aug 2021.

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