1 Toronto Rehabilitation Institute, Toronto, Ontario, Canada.
2 McMaster University, Hamilton, Ontario, Canada.
Neurorehabil Neural Repair. 2018 Mar;32(3):191-199. doi: 10.1177/1545968318760727. Epub 2018 Mar 21.
Executive control deficits are deleterious and enduring consequences of moderate-severe traumatic brain injury (TBI) that disrupt everyday functioning. Clinically, such impairments can manifest as behavioural inconsistency, measurable experimentally by the degree of variability across trials of a reaction time (RT) task (also known as intraindividual variability [IIV]). Growing research on cognition after TBI points to cognitive deterioration in the chronic stages postinjury.
To examine the longitudinal recovery of RT characteristics (IIV and more detailed ex-Gaussian components, as well as the number of impulsively quick responses) following moderate-severe TBI.
Seventy moderate-severe TBI patients were assessed at 2, 5, 12, and 24+ months postinjury on a go/no-go RT task. RT indices (ex-Gaussian parameters mu and sigma [mean and variability of the normal distribution component], and tau [extremely slow responses]; mean, intraindividual coefficient of variation [ICV], and intraindividual standard deviation [ISD]) were analyzed with repeated-measures multivariate analysis of variance.
ICV, ISD, and ex-Gaussian tau significantly decreased (ie, improved) over time in the first year of injury, but worsened from 1 to 2+ years, as did the frequency of extremely fast responses. These quadratic patterns were accentuated by age and shown primarily in tau (extremely slow) and extremely fast (impulsive) responses.
The pattern of early recovery followed by decline in executive control function is consistent with growing evidence that moderate-severe TBI is a progressive and degenerative disorder. Given the responsiveness to treatment of executive control deficits, elucidating the trajectory and underpinnings of inconsistent behavioral responding may reveal novel prognostic and clinical management opportunities.
执行控制缺陷是中度至重度创伤性脑损伤（TBI）的有害且持久的后果，会破坏日常功能。临床上，这些损伤表现为行为不一致，可通过反应时（RT）任务试验之间的变异性程度（也称为个体内变异性[IIV]）进行实验测量。TBI 后认知研究的不断增加表明，损伤后慢性阶段认知能力会恶化。
检查中度至重度 TBI 后 RT 特征（IIV 和更详细的外高斯分量，以及冲动快速反应的数量）的纵向恢复情况。
70 名中度至重度 TBI 患者在损伤后 2、5、12 和 24+个月时，使用 Go/No-Go RT 任务进行评估。使用重复测量多元方差分析对 RT 指数（外高斯参数 mu 和 sigma[正态分布分量的均值和变异性]和 tau[极慢反应]；均值、个体内变异系数[ICV]和个体内标准差[ISD]）进行分析。
在损伤后的第一年，ICV、ISD 和外高斯 tau 随着时间的推移显著降低（即改善），但从 1 年到 2 年以上，极快反应的频率也有所增加。这些二次模式被年龄放大，并主要表现在 tau（极慢）和极快（冲动）反应中。
执行控制功能早期恢复后下降的模式与越来越多的证据一致，即中度至重度 TBI 是一种进行性和退行性疾病。鉴于执行控制缺陷的治疗反应性，阐明不一致行为反应的轨迹和基础可能会揭示新的预后和临床管理机会。
