Assessment of impulsivity after moderate to severe traumatic brain injury

The aim of the study was to develop and validate a short questionnaire assessing four dimensions of impulsivity (urgency, lack of premeditation, lack of perseverance, sensation seeking) in patients with traumatic brain injury (TBI). To this end, 82 patients with TBI and their caregivers completed a short questionnaire adapted from the UPPS Impulsive Behavior Scale designed to assess impulsivity changes after TBI. Confirmatory factor analyses (CFAs) performed on the version of the scale completed by the relatives revealed that a hierarchical model holding that lack of premeditation and lack of perseverance are facets of a higher order construct (lack of conscientiousness), with urgency and sensation seeking as separate correlated factors, fit the data best. Urgency, lack of premeditation, and lack of perseverance increased after the TBI, whereas sensation seeking decreased. CFA failed to reveal a satisfactory model in the version of the scale completed by the patients. The psychological processes related to these impulsivity changes and the discrepancy observed between self-report and informant-report are discussed. This short questionnaire opens up interesting prospects for better comprehension and assessment of behavioural symptoms of TBI.     

Pre-injury assessment of everyday executive function in moderate to severe traumatic brain injury

Executive dysfunction is frequently observed in moderate to severe traumatic brain injury (TBI) and is commonly assessed with objective measures or subjective rating scales. Given the variability in executive function in the normal population, a reliable measure of pre-injury executive function would be of considerable value. In this study we examined pre-injury self and collateral (relative or friend) ratings on the Frontal Systems Behavior Rating Scale (FrSBe). Fifty-one persons with moderate to severe TBI and their collaterals provided before- and after-TBI ratings at 3 months post injury. A subset of 36 dyads were retested at 6 and 12 months; 26 neurologically intact controls and their collaterals also provided FrSBe ratings. At 3 months post injury, the difference between patient and collateral ratings of current status was larger than the difference relating to premorbid status, suggesting that patients were able to rate themselves from a pre-injury perspective. However, pre-injury ratings from collaterals were more reliable over time compared with patients’ self-ratings. For all sets of ratings – before injury, after injury, and status of healthy controls – collateral ratings indicated more abnormality, overall, than comparable self-ratings. Evaluating one’s own executive behaviour may be a difficult task even without TBI, with the difficulty exacerbated by the effects of injury.     

Verbal learning patterns in moderate and severe traumatic. brain injury

Abstract

Previous studies that have examined performances on the California Verbal Learning Test (CVLT) among individuals with traumatic brain injury (TBI) have found differing levels of performance. Differential patterns of performance, however, have only been inferred. The present investigation sought to determine empirically if differential patterns of performance could be discerned in a TBI sample of 65 subjects with CVLT variables. The CVLT variables were selected based on the instrument's factor structure. Cluster analysis yielded four distinct subtypes of brain-injured individuals. The Active subtype demonstrated impaired unassisted retrieval, but used active encoding strategies and showed relatively intact ability to store novel information. The Disorganized subtype demonstrated an inconsistent, haphazard learning style along with deficits in encoding. The Passive subtype was marked by an overreliance on a serial clustering strategy as well as impaired encoding and/or consolidation. The Deficient subtype was the most impaired of all groups, exhibiting a slowed rate of acquisition, passive learning style, and significant impairment in encoding. Implications for rehabilitation are discussed.     

Definite malingered neurocognitive dysfunction in moderate/severe traumatic brain injury

There has been disagreement in the literature about whether persons with documented neuropathology can be diagnosed as malingering. To address this question, we present three moderate severe traumatic brain injury patients who were evaluated in the context of litigation who met the Slick, Sherman, and Iverson (1999) criteria for a diagnosis of "Definite Malingered Neurocognitive Dysfunction." Each performed significantly below-chance on at least one forced-choice symptom validity test, thereby demonstrating a deliberate attempt to appear impaired. These cases represent the first definitive evidence of an intentional effort to appear impaired in the context of documented moderate/severe traumatic brain injury.     

A longitudinal study of awareness of deficit after moderate to severe traumatic brain injury

Lack of awareness of deficits is a common problem after traumatic brain injury (TBI), and is associated with worse functional outcome and poor compliance with rehabilitation. Little is known, however, about the course of awareness of deficits after TBI. Using a longitudinal design, we examined changes in self-awareness between the subacute stage (about 45 days after injury) and one-year follow-up in a sample of 123 individuals with moderate to severe TBI. Awareness of deficits was operationalised as the discrepancy between patient and family ratings on the Awareness Questionnaire (AQ) and Patient Competency Rating Scale (PCRS). Compared to baseline, awareness was improved at one year, as evidenced by smaller discrepancy scores and stronger correlations between participant and family ratings. Changes in awareness were most pronounced for the behavioural/affective domain and least pronounced for the motor/sensory domain, which showed best agreement at baseline. Even at one year, participants rated themselves as higher functioning than did their relatives. Awareness at baseline and, for the AQ, time to follow commands, significantly predicted awareness at one year. These results suggest that awareness of deficits improves between the subacute and post-acute stages after TBI, and highlight the need for effective interventions for persons with impaired awareness and for flexible timing of rehabilitation efforts.     

A longitudinal study of awareness of deficit after moderate to severe traumatic brain injury

Lack of awareness of deficits is a common problem after traumatic brain injury (TBI), and is associated with worse functional outcome and poor compliance with rehabilitation. Little is known, however, about the course of awareness of deficits after TBI. Using a longitudinal design, we examined changes in self-awareness between the subacute stage (about 45 days after injury) and one-year follow-up in a sample of 123 individuals with moderate to severe TBI. Awareness of deficits was operationalised as the discrepancy between patient and family ratings on the Awareness Questionnaire (AQ) and Patient Competency Rating Scale (PCRS). Compared to baseline, awareness was improved at one year, as evidenced by smaller discrepancy scores and stronger correlations between participant and family ratings. Changes in awareness were most pronounced for the behavioural/affective domain and least pronounced for the motor/sensory domain, which showed best agreement at baseline. Even at one year, participants rated themselves as higher functioning than did their relatives. Awareness at baseline and, for the AQ, time to follow commands, significantly predicted awareness at one year. These results suggest that awareness of deficits improves between the subacute and post-acute stages after TBI, and highlight the need for effective interventions for persons with impaired awareness and for flexible timing of rehabilitation efforts.     

Predictions of episodic memory following moderate to severe traumatic brain injury during inpatient rehabilitation

We examined memory self-awareness and memory self-monitoring abilities during inpatient rehabilitation in participants with moderate to severe traumatic brain injury (TBI). A total of 29 participants with moderate to severe TBI and 29 controls matched on age, gender, and education completed a performance prediction paradigm. To assess memory self-awareness, participants predicted the amount of information they would remember before completing list-learning tasks and visual-spatial memory tasks. Memory self-monitoring was assessed by participants' ability to increase accuracy of their predictions after experience with the tests. Although the TBI participants performed more poorly than controls on both episodic memory tasks, no significant group differences emerged in memory self-awareness or memory self-monitoring. The TBI participants predicted that their memory performances would be poorer than that of controls, accurately adjusted their predictions in accordance with the demands of the tasks, and successfully modified their predictions following experience with the tasks. The results indicate that moderate to severe TBI individuals in the early stages of recovery can competently assess the demands of externally driven metamemorial situations and utilize experience with task to accurately update their knowledge of memory abilities.     

Morphometric MRI findings in the thalamus and brainstem in children after moderate to severe traumatic brain injury

Generalized whole brain volume loss is well documented in moderate to severe traumatic brain injury. Whether this atrophy occurs in the thalamus and brainstem has not been systematically studied in children. Magnetic resonance imaging (MRI) quantitative analysis was used to investigate brain volume loss in the thalamus and brainstem in 16 traumatic brain injury subjects (age range 9-16 years) compared with 16 age and demo-graphically matched controls. Based on multiple analysis of covariance, controlling for age and head size, reduced volume in the thalamus and the midbrain region of the brainstem were found. General linear model analyses revealed a relation between processing speed on a working memory task and midbrain and brain stem volumes. Reduced volume in thalamic and brainstem structures were associated with traumatic brain injury. Reduction in midbrain and thalamic volume is probably a reflection of the secondary effects of diffuse axonal injury and reduction in cortical volume from brain injury.     

Prospective evaluation of first and last memory reports following moderate to severe traumatic brain injury

Prospective monitoring of posttraumatic amnesia (PTA) status is recommended following traumatic brain injury (TBI). Use of patients’ subjective reports is, however, still common and necessary in some circumstances. It is therefore important to understand how patients’ self-reported first memories relate to prospective measures and how reliable these reports remain over time. In the present study, patients with moderate–severe TBI in PTA were asked about their first and last memories surrounding the injury daily and were administered the Westmead Post-Traumatic Amnesia Scale (WPTAS). Following PTA emergence, a semistructured interview was used to ascertain participants’ reports of return of continuous memory after the injury, as well as their last preinjury memory. This interview was repeated six months later, along with the Community Integration Questionnaire to measure functional outcome and the Rey Auditory Verbal Learning Test to measure anterograde memory. The temporal order of recovery of WPTAS variables and subjective reports was determined, and consistency of subjective reports over time was examined using bivariate correlation and intraclass correlation coefficients (ICCs). Findings suggested that patients’ reports of return of continuous memory aligned most closely with return of consistent orientation, and occurred significantly earlier than attainment of criterion on the WPTAS. Reported first memories were significantly later at follow-up (i.e., greater days post injury) and the ICC was not suggestive of adequate clinical reliability. Last memory reports were slightly more reliable, with 71% of cases remaining in the same band at follow-up. Demographic and injury-related variables were not significantly associated with the discrepancy between reports. The variability in patients’ reports over time highlights the importance and value of prospective PTA monitoring.     

Dysphagia in severe traumatic brain injury

Dysphagia, or swallowing difficulty, is a common problem following severe traumatic brain injury and is associated with an increased risk of malnutrition and pneumonia. Management of patients with dysphagia following head injury is complicated by the presence of cognitive, communication, and behavioral impairments. The purpose of this review article is to help physicians taking care of traumatic brain injury patients understand and manage dysphagia. The article reviews the history of the study of swallowing, stages of swallowing, impairments of swallowing, neural control of swallowing, and the evaluation of patients with swallowing difficulties and their management. In addition to the general principles of dysphagia management, this article covers the management of dysphagic patients with tracheostomy and their nutritional management.     

Brain activation during a social attribution task in adolescents with moderate to severe traumatic brain injury

The ability to make accurate judgments about the mental states of others, sometimes referred to as theory of mind (ToM), is often impaired following traumatic brain injury (TBI), and this deficit may contribute to problems with interpersonal relationships. The present study used an animated social attribution task (SAT) with functional magnetic resonance imaging (fMRI) to examine structures mediating ToM in adolescents with moderate to severe TBI. The study design also included a comparison group of matched, typically developing (TD) adolescents. The TD group exhibited activation within a number of areas that are thought to be relevant to ToM, including the medial prefrontal and anterior cingulate cortex, fusiform gyrus, and posterior temporal and parietal areas. The TBI subjects had significant activation within many of these same areas, but their activation was generally more intense and excluded the medial prefrontal cortex. Exploratory regression analyses indicated a negative relation between ToM-related activation and measures of white matter integrity derived from diffusion tensor imaging, while there was also a positive relation between activation and lesion volume. These findings are consistent with alterations in the level and pattern of brain activation that may be due to the combined influence of diffuse axonal injury and focal lesions.     

The frequency of cerebral ischemia/hypoxia in pediatric severe traumatic brain injury

Introduction

The frequency of adverse events, such as cerebral ischemia, following traumatic brain injury (TBI) is often debated. Point-in-time monitoring modalities provide important information, but have limited temporal resolution.

Purpose

This study examines the frequency of an adverse event as a point prevalence at 24 and 72?h post-injury, compared with the cumulative burden measured as a frequency of the event over the full duration of monitoring.

Methods

Reduced brain tissue oxygenation (PbtO₂?<?10?mmHg) was the adverse event chosen for examination. Data from 100 consecutive children with severe TBI who received PbtO₂ monitoring were retrospectively examined, with data from 87 children found suitable for analysis. Hourly recordings were used to identify episodes of PbtO₂ less than 10?mmHg, at 24 and 72?h post-injury, and for the full duration of monitoring.

Results

Reduced PbtO₂ was more common early than late after injury. The point prevalence of reduced PbtO₂ at the selected time points was relatively low (10?% of patients at 24?h and no patients at the 72-h mark post-injury). The cumulative burden of these events over the full duration of monitoring was relatively high: 50?% of patients had episodes of PbtO₂ less than 10?mmHg and 88?% had PbtO₂ less than 20?mmHg.

Conclusion

Point-in-time monitoring in a dynamic condition like TBI may underestimate the overall frequency of adverse events, like reduced PbtO₂, particularly when compared with continuous monitoring, which also has limitations, but provides a dynamic assessment over a longer time period.     

IMPACT recommendations for improving the design and analysis of clinical trials in moderate to severe traumatic brain injury

Clinical trials in traumatic brain injury (TBI) pose complex methodological challenges, largely related to the heterogeneity of the population. The International Mission on Prognosis and Clinical Trial Design in TBI study group has explored approaches for dealing with this heterogeneity with the aim to optimize clinical trials in TBI. Extensive prognostic analyses and simulation studies were conducted on individual patient data from eight trials and three observational studies. Here, we integrate the results of these studies into the International Mission on Prognosis and Clinical Trial Design in TBI recommendations for design and analysis of trials in TBI:

重型颅脑损伤术中急性脑膨出应对措施

目的探讨重型颅脑损伤手术中急性脑膨出的机理与处理措施。方法回顾性分析58例在颅脑手术过程中发生脑膨出的重型颅脑损伤患者临床资料,影像学资料及应对措施,采用标准大骨瓣减压、过度通气、咬除颅底骨质、阶梯性减压、及时复查颅脑CT等综合措施。结果术后随访三月按GOS评定预后恢复良好19例、轻残11例、重残11例、植物生存5例、死亡12例。迟发性血肿(63.8%),弥漫性脑肿胀(27.6%)及脑梗死(8.6%)是重型颅脑损伤手术中急性脑膨出的主要原因。结论对重型颅脑损伤手术中急性脑膨出的患者要正确判断,区别原因采取相应的措施。