Concussion and mild traumatic brain injury (mTBI) are recognised as serious medical events that are relatively common in contact sports. Recently, the seemingly non-injurious phenomenon of sub-concussion has gained interest among neuroscience researchers and early studies are showing that there may be some acute and chronic effects on brain health and function with repeated sub-concussive events of the type seen in soccer, where players strike the ball with the head, and collision sports like the rugby codes.

The aim of this narrative review is to describe sub-concussion and the current understanding of short and long term effects of repeated minor impacts that have been found to occur in human and animal models. Here, potential mechanisms for cognitive dysfunction following sub-concussion and recommend directions for future research are discussed.

The Potential mechanisms of injuries resulting from sub-concussion such as changes in blood brain barrier integrity, neuroinflammation, cognitive impairment, and oxidative stress damage, among other changes in central nervous system function vary considerably making understanding of the underlying causative mechanism challenging for researchers.

Some evidence suggests a link between impaired cerebrovascular function and cognitive impairment which poses a potential mechanism linking the two. It is hoped that this review helps guide researchers toward a potential direction of investigations.

脑震荡和轻度创伤性脑损伤 (mTBI) 被认为是接触性运动中相对常见的严重医疗事件。最近，脑震荡这种看似无害的现象引起了神经科学研究人员的兴趣，早期研究表明，足球中反复出现的脑震荡事件可能会对大脑健康和功能产生一些急性和慢性影响，球员用头部击球，以及橄榄球代码等碰撞运动。

这篇叙述性评论的目的是描述亚脑震荡以及目前对人类和动物模型中反复出现的轻微影响的短期和长期影响的理解。在这里，讨论了脑震荡后认知功能障碍的潜在机制，并为未来的研究推荐了方向。

亚脑震荡导致损伤的潜在机制，例如血脑屏障完整性的变化、神经炎症、认知障碍和氧化应激损伤，以及中枢神经系统功能的其他变化，使得研究人员对潜在病因机制的理解存在很大差异。

一些证据表明脑血管功能受损和认知障碍之间存在联系，这构成了将两者联系起来的潜在机制。希望这篇综述有助于引导研究人员走向潜在的研究方向。