There is concern that previous concussion and contact-sport exposure may have negative effects on brain structure and function. Accurately quantifying previous concussion is complicated by the fact that multiple definitions exist, with recent definitions allowing for diagnosis based on the presence of symptoms alone (Concussion in Sport Group criteria; CISG) rather than the presence of acute injury characteristics such as alterations in mental status (American Congress of Rehabilitation Medicine criteria; ACRM). The goals of the current work were to determine the effects of previous concussion and contact-sport exposure on gray matter structure and clinical measures in healthy, young-adult athletes and determine the extent to which these associations are influenced by diagnostic criteria used to retrospectively quantify concussions. One-hundred eight collegiate-aged athletes were enrolled; 106 athletes were included in final analyses (age, 21.37 ± 1.69; 33 female). Participants completed a clinical battery of self-report and neurocognitive measures and magnetic resonance imaging to quantify subcortical volumes and cortical thickness. Semistructured interviews were conducted to measure exposure to contact sports and the number of previous concussions based on CISG and ACRM criteria. There was a significant association of concussion-related and psychological symptoms with previous concussions based on ACRM (ps < 0.05), but not CISG, criteria. Hippocampal volume was inversely associated with the number of previous concussions for both criteria (ps < 0.05). Findings provide evidence that previous concussions are associated with smaller hippocampal volumes and greater subjective clinical symptoms in otherwise healthy athletes and highlight the importance of diagnostic criteria used to quantify previous concussion.

中文翻译：

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大学年龄运动员既往脑震荡与海马体积和症状的关联

人们担心以前的脑震荡和接触运动可能会对大脑结构和功能产生负面影响。由于存在多种定义，准确量化既往脑震荡变得复杂，最近的定义允许仅根据症状的存在（运动组脑震荡标准；CISG）而不是精神状态改变等急性损伤特征的存在进行诊断（美国康复医学会标准；ACRM）。当前工作的目标是确定既往脑震荡和接触运动暴露对健康年轻成年运动员灰质结构和临床测量的影响，并确定这些关联受用于回顾性量化的诊断标准影响的程度脑震荡。招收了一百八名大学生运动员；最终分析包括 106 名运动员（年龄，21.37 ± 1.69；33 名女性）。参与者完成了一系列临床自我报告和神经认知测量以及磁共振成像，以量化皮质下体积和皮质厚度。根据 CISG 和 ACRM 标准进行半结构化访谈，以衡量接触性运动的暴露程度以及之前发生脑震荡的次数。根据 ACRM（ p s < 0.05）而非 CISG 标准，脑震荡相关症状和心理症状与既往脑震荡存在显着关联。对于这两个标准，海马体积与既往脑震荡次数呈负相关（p s < 0.05）。研究结果证明，以往的脑震荡与其他健康运动员的海马体积较小和主观临床症状较大有关，并强调了用于量化既往脑震荡的诊断标准的重要性。