Background. Concussions affect nearly 3 million people a year and are the leading cause of traumatic brain injury–related emergency department visits among youth. Evidence shows neuromotor regions are sensitive to concussive events and that motor symptoms may be the earliest clinical manifestations of neurodegenerative traumatic brain injuries. However, little is known about the effects repeated concussions play on motor learning. Namely, how does concussion acuity (time since injury) affect different behavioral and neurophysiological components of motor learning? Methods. Using a 3-pronged approach, we assessed (1) behavioral measures of motor learning, (2) neurophysiological measures underlying retention of motor learning known as occlusion, and (3) quantitative survey data capturing affective symptoms of each participant. Collegiate student athletes were stratified across 3 groups depending on their concussion history: (1) NonCon, no history of concussion; (2) Chronic, chronic-state of concussion (>1 year postinjury), or (3) Acute, acute state of concussion (<2 weeks postinjury). Results. We found that athletes in both the acute and chronic state of injury following a concussion had impaired retention and aberrant occlusion in motor skill learning as compared with athletes with no history of concussion. Moreover, higher numbers of previous concussions (regardless of the time since injury) correlated with more severe behavioral and neurophysiological motor impairments by specifically hindering neurophysiological mechanisms of learning to affect behavior. Conclusions. These results indicate the presence of motor learning impairment that is evident within 2 weeks postinjury. Our findings have significant implications for the prognosis of concussion and emphasize the need for prevention, but can also direct more relevant rehabilitation treatment targets.

中文翻译：

---

反复脑震荡会损害运动学习系统的行为和神经生理变化

背景。脑震荡每年影响近 300 万人，是青少年因创伤性脑损伤而去急诊室就诊的主要原因。有证据表明，神经运动区对脑震荡事件敏感，运动症状可能是神经退行性创伤性脑损伤的最早临床表现。然而，人们对反复脑震荡对运动学习的影响知之甚少。即，脑震荡敏锐度（受伤后的时间）如何影响运动学习的不同行为和神经生理学组成部分？方法。我们采用三管齐下的方法，评估了（1）运动学习的行为测量，（2）运动学习保留的神经生理学测量（称为闭塞），以及（3）捕获每个参与者情感症状的定量调查数据。根据脑震荡史，将大学生运动员分为 3 组：(1) NonCon，没有脑震荡史；(2) 慢性、慢性脑震荡状态（受伤后 > 1 年），或 (3) 急性、急性脑震荡状态（受伤后 < 2 周）。结果。我们发现，与没有脑震荡病史的运动员相比，脑震荡后处于急性和慢性损伤状态的运动员在运动技能学习中的保持力和咬合异常均受损。此外，以前发生的脑震荡次数较多（无论受伤后的时间长短），通过特别阻碍学习影响行为的神经生理学机制，与更严重的行为和神经生理运动损伤相关。结论。这些结果表明存在运动学习障碍，这种障碍在受伤后 2 周内就很明显。我们的研究结果对脑震荡的预后具有重要意义，强调了预防的必要性，但也可以指导更相关的康复治疗目标。