The purpose of this study was to investigate how concussion history affects neurovascular coupling in Special Operations Forces (SOF) combat Soldiers. We studied 100 SOF combat Soldiers [age = 33.5 ± 4.3 years; height = 180.4 ± 6.0 cm; 55 (55.0%) with self-reported concussion history]. We employed transcranial Doppler (TCD) ultrasound to assess neurovascular coupling (NVC) via changes in posterior cerebral artery (PCA) velocity in response to a reading and a visual search task. Baseline TCD data were collected for 2 min. NVC was quantified by the percent change in overall PCA response curves. We employed linear mixed effect models using a linear spline with one knot to assess group differences in percent change observed in the PCA velocity response curves between SOF combat Soldiers with and without a concussion history. Baseline PCA velocity did not significantly differ (t₉₈ = 1.28, p = 0.20) between those with and without concussion history. Relative PCA velocity response curves did not differ between those with and without a concussion history during the reading task (F_1,98 = 0.80, p = 0.37) or the visual search task (F_1,98 = 0.52, p = 0.47). When assessing only SOF combat Soldiers with a concussion history, differential response to task was significantly greater in those with 3 or more concussions (F_1,4341 = 27.24, p < 0.0001) relative to those with 1–2 concussions. Despite no main effect of concussion history on neurovascular coupling response in SOF combat Soldiers, we observed a dose-response based on lifetime concussion incidence. While long-term neurophysiological effects associated with head impact and blast-related injury are currently unknown, assessing NVC response may provide further insight into cerebrovascular function and overall physiological health.

本研究的目的是调查脑震荡史如何影响特种作战部队 (SOF) 战斗士兵的神经血管耦合。我们研究了 100 名 SOF 战斗士兵 [年龄 = 33.5 ± 4.3 岁；高度 = 180.4 ± 6.0 厘米；55 (55.0%) 有自我报告的脑震荡史]。我们采用经颅多普勒 (TCD) 超声通过大脑后动脉 (PCA) 速度响应阅读和视觉搜索任务的变化来评估神经血管耦合 (NVC)。收集基线 TCD 数据 2 分钟。NVC 通过整体 PCA 响应曲线的百分比变化来量化。我们采用线性混合效应模型，使用带有一个结的线性样条来评估在有和没有脑震荡史的 SOF 战斗士兵之间的 PCA 速度响应曲线中观察到的百分比变化的组差异。t ₉₈ = 1.28, p = 0.20) 有脑震荡史和无脑震荡史的人之间。在阅读任务 ( F _1,98 = 0.80, p = 0.37) 或视觉搜索任务 ( F _1,98 = 0.52, p = 0.47)期间，有和没有脑震荡史的相对 PCA 速度响应曲线没有差异。当仅评估有脑震荡史的 SOF 战斗士兵时，有 3 次或更多脑震荡的士兵对任务的不同反应显着更大 ( F _1,4341 = 27.24, p< 0.0001) 相对于 1-2 次脑震荡的患者。尽管脑震荡史对 SOF 战斗士兵的神经血管耦合反应没有主要影响，但我们观察到了基于终生脑震荡发生率的剂量反应。虽然与头部撞击和爆炸相关损伤相关的长期神经生理学影响目前尚不清楚，但评估 NVC 反应可能会提供对脑血管功能和整体生理健康的进一步了解。