Acute and Chronic Effects of Multiple Concussions on Midline Brain Structures

Area of Science:

• Neuroscience
• Sports Medicine
• Radiology

Background:

• Concussion can cause long-term neurological changes.
• The cumulative impact of repeated concussions on brain physiology is not fully understood.
• Previous head injuries may alter recovery from subsequent concussions.

Purpose of the Study:

• To investigate if a history of concussion (HOC) exacerbates disturbances in cerebral blood flow (CBF) and white matter microstructure.
• To examine these effects during acute and chronic recovery phases after concussion.
• To determine if HOC influences the recovery trajectory and clinical outcomes.

Main Methods:

• Longitudinal magnetic resonance imaging (MRI) study of 61 athletes with concussion (36 with HOC) and 167 controls (73 with HOC).
• Assessed CBF in the cingulate cortex and white matter microstructure (fractional anisotropy and mean diffusivity) of the corpus callosum.
• Utilized linear mixed models to analyze HOC effects over time and the Sport Concussion Assessment Tool (SCAT) for clinical evaluation.

Main Results:

• Athletes with HOC showed significantly greater subacute declines in midcingulate CBF and chronic declines in posterior cingulate CBF.
• Higher mean diffusivity in the splenium of the corpus callosum was observed in athletes with HOC at return to play.
• No significant differences in white matter fractional anisotropy or clinical measures (SCAT, time to RTP) were found between groups.

Conclusions:

• History of concussion is associated with persistent alterations in cingulate CBF and corpus callosum microstructure.
• These physiological changes occur independently of clinical symptom presentation or cognitive/balance deficits.
• Findings highlight cumulative effects of repeated head injuries on brain recovery in young athletes.