Cognitive function and dynamic cerebral blood flow regulation in multiple concussions

Background: Concussion causes acute, short-term brain dysfunctions. However, the impact of repetitive concussion history on brain function remains unclear. Objectives: The present study examined the effect of a history of multiple concussions on the cognitive functions and dynamic cerebral blood flow (CBF) regulation in collegiate rugby football players. Methods: Nine male rugby football players with a history of≤1 concussion and nine players with a history of multiple concussions (≤ 4 concussions) participated in this study. Reaction time and working memory were assessed using a neurocognitive assessment device (CogSport; CogState Ltd., Melbourne, Australia). Arterial blood pressure and middle cerebral artery blood velocity (MCAv) were measured continuously throughout the experiment. Dynamic cerebral autoregulation was examined using a thigh-cuff occlusion and release technique. Results:We found a significant difference in the short-term working memory between players with a history of ≤1 concussion and those with a history of multiple concussions (P < 0.05). However, dynamic cerebral autoregulation was not significantly different between the two groups. Conclusions: We found a dysfunction in the short-term memory function of collegiate rugby football players with a history of multiple concussions. However, this impairment in brain function was not associated with changes in dynamic CBF regulation.