Ecological Assessment of Executive Function in Traumatic Brain Injury

Executive dysfunction is a common outcome in children who have sustained traumatic brain injury (TBI). Appropriate assessment of these complex interrelated regulatory functions is critical to plan for the necessary interventions yet present a challenge to our traditional methodologies. Ecological validity has become an increasingly important focus in neuropsychological assessment with particular relevance for the executive functions, which coordinate one's cognitive and behavioral capacities with real-world demand situations. The Behavior Rating Inventory of Executive Function (BRIEF) was developed to capture the real-world behavioral manifestations of executive dysfunction. Its development and various forms of validity, including ecological validity, are described. Application of the BRIEF's methodology to the assessment of executive dysfunction in TBI is provided. We advocate a multilevel approach to understanding executive function outcome in TBI, including traditional test-based measures of executive function, real-world behavioral manifestation of executive dysfunction, and the environmental system factors that impact the child. In this model, ecologically valid assessment of executive dysfunction provides an important bridge toward understanding the impact of component-level (i.e., test-based) deficits on the child's everyday adaptive functioning, which can assist the definition of targets for intervention.     

Executive Function Profiles in Pediatric Traumatic Brain Injury

Traumatic brain injury (TBI) results in heterogeneous patterns of neuropsychological impairment. This study investigated heterogeneity in executive function (EF) using the Comprehensive Trail Making Test (CTMT) to evaluate 121 children and adolescents with TBI and 121 matched normal controls. The TBI group performed approximately two standard deviations below controls. Cluster analyses indicated that a three-cluster solution best classified the TBI group and a four-cluster solution best classified controls. Greater impairment in EF was associated with lower intellectual, achievement, and neuropsychological test performance in the TBI group. Results suggest that EF deficits reflected in CTMT performance may be useful for classifying severity of TBI.     

Executive Function Outcomes Following Traumatic Brain Injury in Young Children: A Five Year Follow-Up

Little is known about the long-term effects of traumatic brain injury (TBI) in very young children. This study used a prospective, cross-sectional design to investigate the impact of TBI on executive function (EF) outcomes in children who sustained a TBI before the age of seven. The study aimed to identify specific or global EF deficits five years post-TBI, and to explore factors that predicted outcomes. Fifty-four children with a TBI and 17 uninjured comparison children participated. Their performance on several cognitive and behavioral EF measures was examined. Results suggested that executive difficulties were present following severe TBI, however children with mild and moderate injuries were relatively unaffected. Skills that develop early appeared to be relatively robust. Injury severity was found to be most predictive of long-term EF, however other injury, child and family-related variables also contributed to outcomes.     

Executive Functions Following Traumatic Brain Injury in Young Children: A Preliminary Analysis

To examine executive processes in young children with traumatic brain injury (TBI), we evaluated performance of 44 children who sustained moderate-to-severe TBI prior to age 6 and to 39 comparison children on delayed response (DR), stationary boxes, and spatial reversal (SR) tasks. The tasks have different requirements for holding mental representations in working memory (WM) over a delay, inhibiting prepotent responses, and shifting response set. Age at the time of testing was divided into 10- to 35- and 36- to 85-month ranges. In relation to the community comparison group, children with moderate-to-severe TBI scored significantly lower on indexes of WM/inhibitory control (IC) on DR and stationary boxes tasks. On the latter task, the Age × Group interaction indicated that performance efficiency was significantly reduced in the older children with TBI relative to the older comparison group; performance was similar in younger children irrespective of injury status. The TBI and comparison groups did not differ on the SR task, suggesting that shifting response set was not significantly altered by TBI. In both the TBI and comparison groups, performance improved with age on the DR and stationary boxes tasks. Age at testing was not significantly related to scores on the SR task. The rate of acquisition of working memory (WM) and IC increases steeply during preschool years, but the abilities involved in shifting response set show less increase across age groups (Espy, Kaufmann, & Glisky, 2001; Luciana & Nelson, 1998). The findings of our study are consistent with the rapid development hypothesis, which predicts that skills in a rapid stage of development will be vulnerable to disruption by brain injury.     

Selective Changes in Executive Functioning Ten Years After Severe Childhood Traumatic Brain Injury

Pediatric traumatic brain injury (TBI) impacts on children's executive functions, but little is known of how such deficits evolve in the long term. Forty adolescents with TBI were assessed ten years post-injury and compared to 19 typically developing participants on a range of executive measures (attentional control, cognitive flexibility, goal setting, information processing). Children with mild or moderate TBI performed within age expectations on all tests; however, those with severe injuries had poorer performance on goal setting and processing speed tasks. Childhood TBI may result in subtle lasting changes in complex executive skills, which could require ongoing support into adulthood.     

长期慢性脑外伤大鼠脑线粒体功能的变化

研究长期慢性轻度脑外伤对大鼠脑线粒体功能的影响。大鼠连续1、5、10、15、20、25、30d轻度闭合性颅脑撞击后分离脑线粒体,测定线粒体肿胀度、膜流动性、膜磷脂含量、呼吸功能、线粒体呼吸酶、超氧化物歧化酶(SOD)、丙二醛(MDA)和Ca2 等指标以显示线粒体功能、抗氧化能力的变化。结果显示,第15、20、25、30d大鼠脑线粒体明显肿胀,膜磷脂降解,膜流动性下降,呼吸功能衰减,呼吸酶、SOD活性降低,Ca2 、MDA含量升高。由此认为,经常性头部撞击可造成大鼠脑线粒体功能受损,其机制可能与脑线粒体膜损伤后继发的自由基生成增加、脑线粒体能量代谢障碍有关。     

Sports Neuropsychology: Assessment and Management of Traumatic Brain Injury

The speed of information processing was examined in a group of patients in the early stages of Alzheimer's disease (AD) and in a group of healthy, age‐and educationally matched controls. Subjects were tested on auditory simple‐reaction time (RT), visual choice‐RT, and combined simple‐ and choice‐RT tasks. The choice‐RT task required elementary linguistic or visuoperceptual matching of successively presented stimuli. AD patients had normal simple RTs but had delayed RTs on the matching tasks, suggesting a slower rate of processing for the component mental operations of the matching tasks. Estimates of the attentional demands or costs of these mental operations—stimulus encoding, decision making, and response selection—were obtained by combining the matching task with the simple‐RT task (probe‐RT). AD patients again showed a significant slowing in choice‐RT, although they exhibited normal accuracy or performance outcome. AD patients also showed increased attentional cost for letter encoding (as reflected in increased probe‐RT) but not for the other constituent mental operations. The results suggest that the differential slowing of choice‐RT in AD is related to the complexity and attentional demands associated with coordinating and executing the matching tasks.     

Malingering and Defensiveness in the Neuropsychological Assessment of Mild Traumatic Brain Injury

A balanced approach to the detection of malingering and defensiveness in the neuropsychological assessment of mild traumatic brain injury (MTBI) is suggested, while genuine neurobehavioral and psychopathological sequelae are documented. The absence of neuroradio-loglcal evidence and heavy reliance on patient report and neuropsychological test data make malingering and defensiveness issues that are critical in forensic contexts and for the credibility of neuropsychology. Deficiencies in interview data collection and the relative strengths and weaknesses of the MMPI (Minnesota Muttiphasic Personality Inventory) are reviewed. The potential independence of malingering and defensiveness and of MMPI and neuropsychological data are noted. The equivocal research on malingering is reviewed, with particular emphasis on assessment of memory deficits as one of the most common complaints in MTBI. Arguably, malingering is more similar to than different from other diagnoses, but it has not been so treated in clinical practice. The need for developing sophisticated malingering probes is acknowledged, but the quest for a single malingering test is criticized and preference given to approaches that rely on evaluating data patterns indicating malingering.     

Long-Term Executive Functioning Outcomes for Complicated and Uncomplicated Mild Traumatic Brain Injury Sustained in Early Childhood

This study investigated long-term executive functioning following early mild traumatic brain injury (TBI), differentiating between complicated (n = 34) and uncomplicated injuries (n = 18). Children post mild TBI were compared to 33 controls at least 7-years post-injury. The complicated mild TBI group performed significantly worse on divided attention compared to both groups, with younger age at injury and neurological symptoms predictors of outcome. No significant group differences existed on speed of information processing, selective attention, working memory, or goal setting. These findings indicate that specific aspects of executive function are compromised by early complicated mild TBI and argue for a stratified definition of mild TBI.     

限制性液体复苏对重型颅脑创伤患者凝血功能的影响

目的 观察限制性液体复苏(LFR)对重型颅脑创伤(sTBI)患者凝血功能的影响.方法 以随机数字表法将2013年3月至2017年3我院收治的116例sTBI患者分为2组,各58例,A组选择限制性液体复苏方法,B组选择常规积极液体复苏方法,比较2组ICU入住时间、平均住院时间、复苏效果(胶体液量、总输液量、红细胞压积、血清乳酸水平与血小板计数)、入院时与治疗24h后凝血功能[纤维蛋白原(FIB)、D-二聚体(D-D)、凝血酶时间(TT)、凝血酶原时间(PT)以及活化部分凝血活酶时间(APTT)]、并发症与预后情况.结果 2组胶体液量比较差异无统计学意义(P＞0.05);A组ICU入住时间、平均住院时间、TT、PT、APTT均显著短于B组(P＜0.05);A组总输液量、血清乳酸、D-D水平明显低于B组(P＜0.05),血小板计数、红细胞压积、FIB水平明显高于B组(P＜0.05);A组并发症总发生率(8.62％)显著低于B组(24.14％)(P＜0.05),且预后总良好率(62.07％)显著高于B组(43.10％)(P＜0.05).结论 对sTBI患者给予LFR治疗,可有效改善机体凝血障碍及预后,促进其恢复,获得良好复苏效果,且降低各种并发症风险.     

脑外伤患者检测血浆IL-11的临床评价

目的：揭示脑外伤患者血浆白介素-11（IL-11）浓度的变化,探讨其在脑损伤中的作用及对预后的预测价值。方法：收集重型脑外伤患者作为脑外伤组,共112例。收集同期健康体检正常人作为正常对照组,共40例。正常对照组静脉血体检时获得。脑外伤组静脉血在入院时获得。ELISA测定血浆IL-11浓度。结果：脑外伤后1个月内死亡31例（27.7%）。血浆IL-11浓度（25.8±10.4）pg/ml显著高于正常对照组（10.9±3.2）pg/ml（P〈0.001）。入院时GCS评分与血浆IL-11浓度呈显著负相关（r=-0.616,P〈0.001）。Logistic回归分析显示,入院时血浆IL-11浓度（OR=1.231,95%CI=1.110～1.349,P〈0.01）是脑外伤后1个月内死亡的危险因素。ROC曲线分析显示,血浆IL-11浓度预测脑外伤后1个月内死亡有显著预测价值（曲线下面积=0.798,95%CI=0.704～0.875,P〈0.001）,且判定血浆IL-11浓度截止值为27.4pg/ml,对预测脑外伤后1个月内死亡有80.7%的灵敏度和74.1%的特异度。结论：脑外伤后血浆IL-11浓度升高,可能参与脑损伤的炎症反应,临床检测这个指标有助于早期判断脑外伤患者的预后。     

Information Communication Networks in Severe Traumatic Brain Injury

In this study we explored the use of coherence and Granger causality (GC) to separate patients in minimally conscious state (MCS) from patients with severe neurocognitive disorders (SND) that show signs of awareness. We studied 16 patients, 7 MCS and 9 SND with age between 18 and 49 years. Three minutes of ongoing electroencephalographic (EEG) activity was obtained at rest from 19 standard scalp locations, while subjects were alert but kept their eyes closed. GC was formulated in terms of linear autoregressive models that predict the evolution of several EEG time series, each representing the activity of one channel. The entire network of causally connected brain areas can be summarized as a graph of incompletely connected nodes. The 19 channels were grouped into five gross anatomical regions, frontal, left and right temporal, central, and parieto-occipital, while data analysis was performed separately in each of the five classical EEG frequency bands, namely delta, theta, alpha, beta, and gamma. Our results showed that the SND group consistently formed a larger number of connections compared to the MCS group in all frequency bands. Additionally, the number of connections in the delta band (0.1–4 Hz) between the left temporal and parieto-occipital areas was significantly different (P < 0.1%) in the two groups. Furthermore, in the beta band (12–18 Hz), the input to the frontal areas from all other cortical areas was also significantly different (P < 0.1%) in the two groups. Finally, classification of the subjects into distinct groups using as features the number of connections within and between regions in all frequency bands resulted in 100% classification accuracy of all subjects. The results of this study suggest that analysis of brain connectivity networks based on GC can be a highly accurate approach for classifying subjects affected by severe traumatic brain injury.     

Clinical Features of Repetitive Traumatic Brain Injury and Chronic Traumatic Encephalopathy

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease characterized by a distinct pattern of hyperphosphorylated tau (p‐tau). Thought to be caused by repetitive concussive and subconcussive injuries, CTE is considered largely preventable. The majority of neuropathologically confirmed cases have occurred in professional contact sport athletes (eg, boxing, football). A recent post‐mortem case series has magnified concerns for the public's health following its identification in six high school level athletes. CTE is diagnosed with certainty only following a post‐mortem autopsy. Efforts to define the etiology and clinical progression during life are ongoing. The goal of this article is to characterize the clinical concepts associated with short‐ and long‐term effects of repetitive traumatic brain injury, with a special emphasis on new clinical diagnostic criteria for CTE. Utilizing these new diagnostic criteria, two cases of neuropathologically confirmed CTE, one in a professional football player and one in a professional boxer, are reported. Differences in cerebellar pathology in CTE confirmed cases in boxing and football are discussed.     

脑外伤病人记忆功能的康复特点

脑外伤现已成为危害人们健康的主要疾病之一。脑外伤会引起多种认知功能障碍 ,如注意、记忆和语言等 ,其中记忆障碍较为常见。脑外伤后会有一段时间失去意识 ,同时伴有失定向、意识混乱 ,以及情节记忆受损等症状 ,称为创伤后遗忘 (ｐｏｓｔｔｒａｕ ｍａｔｉｃａｍｎｅｓｉａ ,ＰＴＡ) [1- 3] 。ＰＴＡ可以持续几分钟或几个月不等 ,它对于预测脑外伤后认知功能康复的程度等有重要的参考价值 ,ＰＴＡ的持续时间短 ,程度轻 ,其后认知功能的康复就会较好。对ＰＴＡ最简单的评价是询问病人在外伤后能够记起的第一件事 ,以及病人能够记起的外伤前…     

创伤性颅脑损伤频响特性研究综述

频率在创伤性颅脑损伤(traumatic brain injury, TBI)的生物力学响应中扮演着重要角色,冲击载荷可因共振行为而放大脑部局部变形,加剧神经功能障碍。 本文总结了颅脑损伤频响特性的主要研究方法和发展进程,重点探讨不同数学方法在颅脑损伤频响特性中的应用,以及颅脑损伤频响特性的研究现状,并进一步提出深化颅脑损伤频响特性研究的建议。 结果表明,有限元法、降阶模型法和流固耦合法在颅脑损伤频响特性研究中均具可行性,但现有研究对颅脑固有频率尚未达成有效共识,且未将颅脑损伤的频响特性与评价准则进行结合,故基于频响特性完善颅脑损伤力学评价仍是研究的重点。