Objective findings of brain injury or dysfunction are typically lacking in mild traumatic brain injury (MTBI) despite prolonged post-concussion symptoms in some patients. Thus, there is a need for objective biomarkers of MTBI that reflect altered brain physiology underlying subjective symptoms. We have previously reported increased attention to threat-related stimuli in subjects with MTBI suggesting a physiological vulnerability to depression. Vulnerability to depression has been linked with relatively greater activity of the right than left frontal cortex reflected in inverse pattern in frontal alpha with greater power on the left than right. We investigated whether patients with previous MTBI show this pattern of frontal activity reflected in more negative frontal alpha asymmetry (FAA) scores. Furthermore, in search for potential biomarkers of MTBI, we created a novel index, emotional modulation of FAA (eFAA) and investigated whether it correlates with subjective symptoms. EEG was recorded while subjects with previous MTBI and controls performed a computer-based reaction time task integrating different cognitive executive functions and containing either threat-related or emotionally neutral visual stimuli. Post-concussion symptoms and depression were assessed using the Rivermead Post-Concussion Symptoms Questionnaire (RPQ) and Beck’s depression inventory (BDI). Task-induced FAA was assessed and eFAA calculated by subtracting FAA in the context of neutral stimuli from FAA in the context of emotional stimuli. The MTBI group showed FAA scores reflecting relatively greater right-sided frontal activity compared to healthy controls. eFAA differentiated the symptomatic MTBI from non-symptomatic MTBI group and from healthy controls. eFAA also correlated with RPQ and BDI scores. In conclusion, FAA pattern previously linked with vulnerability to depression, was observed in patients with previous MTBI. Furthermore, eFAA has potential as a biomarker of altered affective brain functions in MTBI.

中文翻译：

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额叶α不对称的情绪调节——轻度创伤性脑损伤的新型生物标志物


尽管一些患者出现长期脑震荡后症状，但轻度创伤性脑损伤（MTBI）通常缺乏脑损伤或功能障碍的客观发现。因此，需要 MTBI 的客观生物标志物来反映主观症状背后的大脑生理学改变。我们之前曾报道过 MTBI 受试者对威胁相关刺激的关注增加，这表明他们在生理上容易患抑郁症。抑郁症的易感性与右侧额叶皮层的活动相对较大有关，这反映在额叶阿尔法的相反模式中，左侧的能量比右侧的能量更大。我们调查了既往有 MTBI 的患者是否表现出这种额叶活动模式，该模式反映在额叶 α 不对称性 (FAA) 分数为负值中。此外，为了寻找 MTBI 的潜在生物标志物，我们创建了一个新的指数：FAA 情绪调节 (eFAA)，并研究它是否与主观症状相关。当具有先前 MTBI 的受试者和对照组执行基于计算机的反应时间任务时，记录脑电图，该任务整合了不同的认知执行功能，并包含与威胁相关或情绪中性的视觉刺激。使用 Rivermead 脑震荡后症状问卷 (RPQ) 和 Beck 抑郁量表 (BDI) 评估脑震荡后症状和抑郁症。评估任务诱发的 FAA，并通过从情绪刺激背景下的 FAA 中减去中性刺激背景下的 FAA 来计算 eFAA。 MTBI 组的 FAA 评分反映出与健康对照组相比，右侧额叶活动相对较多。 eFAA 将有症状的 MTBI 与无症状的 MTBI 组以及健康对照区分开来。 eFAA 还与 RPQ 和 BDI 分数相关。总之，在既往 MTBI 患者中观察到 FAA 模式先前与抑郁症易感性相关。此外，eFAA 有潜力作为 MTBI 中情感脑功能改变的生物标志物。