Traumatic brain injury: guidance in a forensic context from outcome, dose-response, and response bias research

Molecular biomarkers of diffuse axonal injury: recent advances and future perspectives

INTRODUCTION

Diffuse axonal injury (DAI), with high mortality and morbidity both in children and adults, is one of the most severe pathological consequences of traumatic brain injury. Currently, clinical diagnosis, disease assessment, disability identification, and postmortem diagnosis of DAI is mainly limited by the absent of specific molecular biomarkers.

AREAS COVERED

In this review, we first introduce the pathophysiology of DAI, summarized the reported biomarkers in previous animal and human studies, and then the molecular biomarkers such as β-Amyloid precursor protein, neurofilaments, S-100β, myelin basic protein, tau protein, neuron-specific enolase, Peripherin and Hemopexin for DAI diagnosis is summarized. Finally, we put forward valuable views on the future research direction of diagnostic biomarkers of DAI.

EXPERT OPINION

In recent years, the advanced technology has ultimately changed the research of DAI, and the numbers of potential molecular biomarkers was introduced in related studies. We summarized the latest updated information in such studies to provide references for future research and explore the potential pathophysiological mechanism on diffuse axonal injury.

Utility of CVLT-3 response bias as a measure of performance validity after traumatic brain injury

OBJECTIVE

We sought to determine the utility of a new performance validity index that was recently proposed. In particular, we wanted to determine if this index would be associated with a specificity of at least .90, a sensitivity of at least .40, and an Area Under the Curve of at least .70 in a traumatic brain injury (TBI) sample.

METHOD

We used logistic regression to investigate how well this new index could distinguish persons with TBI (n = 148) who were evaluated within 1-36 months after injury. All participants had been classified on the basis of at least two independent performance validity tests as having provided valid performance (n = 128) or invalid performance (n = 20).

RESULTS

The new performance validity index had acceptable specificity (.96) but had suboptimal sensitivity (.35) and Area Under the Curve (.66). It was concerning that almost half (5/12) of the cases that were identified by this index as providing invalid effort were false positives. Although a slightly more liberal cut-off improved sensitivity, the problem with poor positive predictive power remained. The conventional Forced Choice index had relatively better classification accuracy.

CONCLUSION

Differences in base rates between the original sample of Martin et al. and the current one most likely affected positive predictive power of the new index. Although their performance validity has excellent specificity, the current results do not support the application of this index in the clinical evaluation of patients with traumatic brain injury when base rates of invalid performance differ markedly from those in the original study.

Utility of the D-KEFS color word interference test as an embedded measure of performance validity after traumatic brain injury

ObjectiveWe sought to determine the accuracy of embedded performance measures for the D-KEFS Color Word Interference Test that were recently proposed by Eglit et al. In particular, we wanted to determine if these indices would be associated with a specificity of at least .90, an Area Under the Curve of at least .70 and a positive likelihood ratio of at least 2. Method: We used logistic regression to investigate how well these indices could distinguish persons with traumatic brain injury (n = 169) who were evaluated within 1-12 months after injury. All participants had been classified on the basis of at least three independent performance validity tests as valid performance (n = 145) or invalid performance (n = 24). Results: None of the three indices that Eglit et al. had proposed as embedded performance measures for the D-KEFS Color Word Interference Test achieved the a priori defined minimally acceptable level of specificity. One of them did meet the criteria for Area Under the Curve as well as positive likelihood ratio. Conclusion: The current results do not support the application of the Eglit et al. embedded performance validity measures for the D-KEFS Color Word Interference Test in the clinical evaluation of patients with traumatic brain injury.

Inefficient Attentional Control Explains Verbal-Memory Deficits Among Military Veterans With Posttraumatic Reexperiencing Symptoms

Among individuals with posttraumatic stress disorder (PTSD), verbal learning and memory are areas of weakness compared with other cognitive domains (e.g., visuospatial memory). In this study, previously deployed military veterans completed clinical assessments of word memory and vocabulary (n = 243) and a laboratory task measuring encoding, free recall, repetition priming, and recognition of words (n = 147). Impaired verbal memory was selectively related to reexperiencing symptoms of PTSD but was not associated with other symptom groupings or blast-induced traumatic brain injury. Implicit priming of response times following word repetition was also unrelated to clinical symptoms. Instead, slowed response times during encoding explained associations between reexperiencing and memory performance. These findings are consistent with alterations in attentional control explaining PTSD-related verbal-memory deficits. Such findings have implications for understanding trauma-focused psychotherapy and recovery, which may depend on efficient attentional processing of words to alter posttraumatic reexperiencing symptoms.

American Academy of Clinical Neuropsychology (AACN) 2021 consensus statement on validity assessment: Update of the 2009 AACN consensus conference statement on neuropsychological assessment of effort, response bias, and malingering

Objective: Citation and download data pertaining to the 2009 AACN consensus statement on validity assessment indicated that the topic maintained high interest in subsequent years, during which key terminology evolved and relevant empirical research proliferated. With a general goal of providing current guidance to the clinical neuropsychology community regarding this important topic, the specific update goals were to: identify current key definitions of terms relevant to validity assessment; learn what experts believe should be reaffirmed from the original consensus paper, as well as new consensus points; and incorporate the latest recommendations regarding the use of validity testing, as well as current application of the term 'malingering.' Methods: In the spring of 2019, four of the original 2009 work group chairs and additional experts for each work group were impaneled. A total of 20 individuals shared ideas and writing drafts until reaching consensus on January 21, 2021. Results: Consensus was reached regarding affirmation of prior salient points that continue to garner clinical and scientific support, as well as creation of new points. The resulting consensus statement addresses definitions and differential diagnosis, performance and symptom validity assessment, and research design and statistical issues. Conclusions/Importance: In order to provide bases for diagnoses and interpretations, the current consensus is that all clinical and forensic evaluations must proactively address the degree to which results of neuropsychological and psychological testing are valid. There is a strong and continually-growing evidence-based literature on which practitioners can confidently base their judgments regarding the selection and interpretation of validity measures.

Brain Trauma Mortality Rate Score Scale (BTMRSS): Postmortem Evaluation of the Events

Objective

Brain trauma and its burden is becoming a significant cause of permanent damage and deterioration. Prioritization at the place of the incident and calculation of mortality are leading factors for the final management, but all of them are obtained from living patients. When the autopsies are made there is no actual score system to guide the forensic scientists in their conclusions. Should all of the cadavers with traumatic brain injury (TBI) have been dead? Therefore, we aim to present a score system—brain trauma mortality score scale (BTMSS), aiming to evaluate postmortem the actual risk of mortality.

Methods

We established a score scale, which could be used on cadavers for the evaluation of the events. Afterwards, we applied this score scale on the reports of the cadavers who suffered blunt force TBI for a 10-year period of time between 2007 and 2016. Thereafter, the results were processed with SPSS version 25.

Results

The outcome showed that there is a significant difference between the scores of the cadavers who died at the place of the incident and those who died in hospital thus approving that the BTMSS works well, as well as the importance of level I trauma center.

Conclusion

Every score system could show something useful for the management of the TBIs. The solution and improvement in the outcome of the current study would be a level I trauma center with a qualified neurosurgical department.

Construct validity for the verbal associated pairs screen

The present study introduces the Verbal Associated Pairs Screen (VAPS) as a new measure for assessing performance validity in pediatric populations. This study presents initial data on psychometric properties and establishes construct validity for the VAPS in a sample of 30 adolescent healthy controls and 206 youths with traumatic brain injury (TBI: moderate/severe, N = 30; mild, N = 176). The control group's age (M = 14.93, SD = 1.8) was significantly higher than the moderate/severe TBI (M = 13.9, SD = 2.8), t(68.508) = -3.038, p = .003, and mild TBI (mTBI) groups (M = 14, SD = 2.8), t(54.147) = 2.038, p = .046. The TBI groups were administered the VAPS in accord with other established performance validity tests (PVTs) and well-established  memory tests as part of routine clinical evaluations. The healthy control group was administered the VAPS only. VAPS score distributions for the control group were negatively skewed and highly kurtotic. VAPS scores from the moderate/severe TBI and control groups were indistinguishable for Trial 2 (U = 274, p < .01) and the Delay (U = 396, p = .218). In the mTBI group, convergent and divergent validity was established with other well-validated PVTs and memory tests, respectively. ROC curve analyses identified optimal cutoff scores for the VAPS Total Score, with acceptable sensitivity (55%) and excellent specificity (100%), as well as strong detectability (AUC = .829, 95% CI: 0.731 - 0.928, p < .001). Clinical applications, limitations, and directions for future research with the VAPS are discussed.

Negative impact of litigation procedures on patient outcomes four years after severe traumatic brain injury: results from the PariS-traumatic brain injury study

PURPOSE

To analyze the effect of litigation procedures on long-term outcomes in severe traumatic brain injury.

MATERIALS AND METHODS

Prospective observational follow-up of an inception cohort including 504 adults with severe traumatic brain injury recruited in 2005-2007 in the Parisian area, France, with initial, one- and four-year outcomes measures.

RESULTS

Four years after the traumatic brain injury, 147 patients, out of 257 who survived the acute phase, were assessed. Among these patients, 53 patients declared being litigants and 78 nonlitigants (litigation status was unknown in 16 cases). Sociodemographic characteristics, type of injury and initial severity did not differ significantly between litigants and nonlitigants, except for Injury Severity Score (worse in litigants) and the proportion of road traffic accidents (higher in litigants). One- and four-year outcomes were significantly worse in litigants for autonomy, participation, psychiatric and cognitive function but not quality of life (measured with the Glasgow Outcome Scale-Extended, the working activity status, the Brain Injury Community Rehabilitation Outcome, the Hospital Anxiety and Depression scale, the Neurobehavioral Rating Scale-revised and the Quality of Life after Brain Injury, respectively). Multivariate analyses highlighted litigation procedure as an independent significant predictor of lower autonomy, participation and psychiatric function and tended to predict lower cognitive function, but not lower quality of life, after adjustment for pretrauma characteristics, Injury Severity Score, road traffic accidents and work-related accident status.

CONCLUSIONS

Patients with severe traumatic brain injury have a worse prognosis when involved in a litigation procedure and require special attention in clinical practice. Implications for rehabilitation The influence of litigation procedure on health and social outcomes in severe traumatic brain injury is a major issue that entail numerous levels of complexities. A wide range of interactions and factors related to the prolonged process of litigation against a third party may influence recovery. Results from the PariS-Traumatic Brain Injury study suggest that patients with a severe Traumatic Brain Injury who are involved in a litigation procedure within French jurisdiction compensation scheme have a worse prognosis than patients who do not. Health professionals should be aware of the potential adverse effects of litigation procedures on recovery, and provide appropriate interventions and information to patients and families in such cases.

Assessment of feigned cognitive impairment in severe traumatic brain injury patients with the Forced-choice Graphics Memory Test

INTRODUCTION

The Forced-choice Graphics Memory Test (FGMT) is a newly developed measure to assess feigned cognitive impairment. This study investigated the ability and reliability of FGMT for identification of malingering in patients with traumatic brain injury (TBI).

METHODS

The FGMT was administered to 40 healthy volunteers instructed to respond validly (Healthy Control, H-C), 40 healthy volunteers instructed to feign cognitive impairment (Healthy Malingering, H-M), 40 severe TBI patients who responded validly (TBI control, TBI-C), and 30 severe TBI patients who evidenced invalid performance (TBI malingering, TBI-M).

RESULTS

Both malingering groups (H-M and TBI-M) performed much more poorly than the nonmalingering groups (H-C and TBI-C). The FGMT overall total score, score on easy items, and score on hard items differed significantly across the four groups. The total score showed the highest classification accuracy in differentiating malingering from nonmalingering. A cutoff of less than 18 (total items) successfully identified 95% of TBI-C and 93.3% of TBI-M participants. The FGMT also demonstrated high test-retest reliability and internal consistency. FGMT scores were not affected by TBI patients' education, gender, age, or intelligence.

CONCLUSION

Our results suggest that the FGMT can be used as a fast and reliable tool for identification of feigned cognitive impairment in patients with TBI.

Effort, symptom validity testing, performance validity testing and traumatic brain injury

BACKGROUND

To understand the neurocognitive effects of brain injury, valid neuropsychological test findings are paramount.

REVIEW

This review examines the research on what has been referred to a symptom validity testing (SVT). Above a designated cut-score signifies a 'passing' SVT performance which is likely the best indicator of valid neuropsychological test findings. Likewise, substantially below cut-point performance that nears chance or is at chance signifies invalid test performance. Significantly below chance is the sine qua non neuropsychological indicator for malingering. However, the interpretative problems with SVT performance below the cut-point yet far above chance are substantial, as pointed out in this review. This intermediate, border-zone performance on SVT measures is where substantial interpretative challenges exist. Case studies are used to highlight the many areas where additional research is needed. Historical perspectives are reviewed along with the neurobiology of effort. Reasons why performance validity testing (PVT) may be better than the SVT term are reviewed.

CONCLUSIONS

Advances in neuroimaging techniques may be key in better understanding the meaning of border zone SVT failure. The review demonstrates the problems with rigidity in interpretation with established cut-scores. A better understanding of how certain types of neurological, neuropsychiatric and/or even test conditions may affect SVT performance is needed.