1 Department of Biomedical Engineering, Wake Forest School of Medicine, Winston-Salem, North Carolina.
2 Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas.
J Neurotrauma. 2019 May 15;36(10):1561-1570. doi: 10.1089/neu.2018.6037. Epub 2019 Jan 9.
During normal participation in football, players are exposed to repetitive subconcussive head impacts, or impacts that do not result in signs and symptoms of concussion. To better understand the effects of repetitive subconcussive impacts, the biomechanics of on-field head impacts and resulting brain deformation need to be well characterized. The current study evaluates local brain response to typical youth football head impacts using the atlas-based brain model (ABM), an anatomically accurate brain finite element (FE) model. Head impact kinematic data were collected from three local youth football teams using the Head Impact Telemetry (HIT) System. The azimuth and elevation angles were used to identify impacts near six locations of interest, and low, moderate, and high acceleration magnitudes (5th, 50th, and 95th percentiles, respectively) were calculated from the grouped impacts for FE simulation. Strain response in the brain was evaluated by examining the range and peak maximum principal strain (MPS) values in each element. A total of 40,538 impacts from 119 individual athletes were analyzed. Impacts to the facemask resulted in 0.18 MPS for the high magnitude impact category. This was 1.5 times greater than the oblique impact location, which resulted in the lowest strain value of 0.12 for high magnitude impacts. Overall, higher strains resulted from a 95th percentile lateral impact (41.0, 2556 rad/sec) with two predominant axes of rotation than from a 95th percentile frontal impact (67.6, 2641 rad/sec) with a single predominant axis of rotation. These findings highlight the importance of accounting for directional dependence and relative contribution of axes of rotation when evaluating head impact response.
在正常参与足球运动时，球员会受到重复性亚临床脑震荡的冲击，即不会导致脑震荡的症状和体征的冲击。为了更好地了解重复性亚临床冲击的影响，需要对场上头部冲击的生物力学和由此产生的大脑变形进行很好的描述。本研究使用基于图谱的大脑模型（ABM）评估了典型的青少年足球头部冲击对大脑的局部反应，ABM 是一种解剖学上准确的大脑有限元（FE）模型。使用 Head Impact Telemetry（HIT）系统从三个当地青年足球队中收集了头部冲击运动学数据。方位角和仰角用于识别六个感兴趣区域附近的冲击，分别从分组冲击中计算出低、中、高加速度幅度（5%、50%和 95%），用于 FE 模拟。通过检查每个元素中的应变范围和峰值最大主应变（MPS）值来评估大脑中的应变响应。共分析了 119 名运动员的 40538 次冲击。面罩冲击导致高幅度冲击类别中的 MPS 为 0.18。这比斜向冲击位置高出 1.5 倍，后者在高幅度冲击下产生的应变值最低，为 0.12。总体而言，95%的横向冲击（41.0，2556rad/sec）产生的应变比 95%的正面冲击（67.6，2641rad/sec）产生的应变更大，正面冲击的旋转轴只有一个。这些发现强调了在评估头部冲击反应时，考虑到旋转轴的方向依赖性和相对贡献的重要性。
