Neuropsychological outcome from uncomplicated mild, complicated mild, and moderate traumatic brain injury in US military personnel

Health outcomes before and during the COVID-19 pandemic in caregivers of service members and veterans with traumatic brain injury

PURPOSE

To examine change in health-related quality of life (HRQOL) during the COVID-19 pandemic in caregivers of service members/veterans (SMVs) with traumatic brain injury (TBI), by comparing HRQOL during the first year of the pandemic to HRQOL 12 months pre-pandemic.

METHODS

Caregivers (N = 246) were classified into three COVID-19 Pandemic Impact groups based on impact ratings of the pandemic on HRQOL: No Impact (n = 50), Mild Impact (n = 117), and Moderate-Severe Impact (n = 79). Caregivers completed 19 measures across physical, social, caregiving, and economic HRQOL domains, and a measure of SMV Adjustment. T-scores were used to determine individual symptom trajectories for each measure as follows: Asymptomatic (pre + during < 60 T); Developed (pre < 60 + during ≥ 60 T); Improved (pre ≥ 60 T + during < 60 T); and Persistent (pre + during ≥ 60 T).

RESULTS

Using ANOVA, during the pandemic, the Moderate-Severe Impact group reported worse scores on 19 measures (d = 0.41-0.89) compared to the No Impact group and 18 measures (d = 0.31-0.62) compared to the Mild Impact group (d  = 0.31-0.38). The Mild Impact group reported worse scores on two measures compared to the No Impact group (d = 0.42-0.43). Using the entire sample, the majority of HRQOL measures were classified as Asymptomatic (47.2-94.7%), followed by Persistent (2.4-27.2%). Few were classified as Developed (0.4-12.6%) or Improved (2.4-13.8%). Using repeated measures ANOVA, no meaningful effects sizes were found for mean scores on all measures completed pre-pandemic compared to during the pandemic (d ≤ 0.17).

CONCLUSION

The vast majority of caregivers reported stability in HRQOL pre-pandemic compared to during the pandemic. The COVID-19 pandemic was not associated with a high prevalence of decline in caregiver HRQOL.

Cognitive Outcome After Complicated Mild Traumatic Brain Injury: A Literature Review and Meta-Analysis

Cognitive outcome for mild traumatic brain injury (mTBI) with positive brain imaging (complicated mTBI) was compared with that for mTBI with normal imaging (uncomplicated mTBI) and with moderate to severe TBI, using meta-analysis. Twenty-three studies utilizing objective neurocognitive tests were included in the analysis. At less than 3 months post-injury, complicated mTBI was associated with poorer cognitive outcomes than uncomplicated mTBI, but deficits were not comparable to those with moderate-severe TBI. After 3 months post-injury, a similar pattern was detected. Beyond 3 months, deficits in complicated mTBI relative to those with uncomplicated mTBI were present in processing speed, memory, executive function, and language, although the latter may be the result of reduced semantic fluency. The effect size of deficits in these domains was more marked in moderate-severe TBI. The available data support the use of complicated mTBI as a distinct classification in the prediction of cognitive outcome. The extent of cognitive deficit in complicated mTBI was small and unlikely to cause significant disability. However, patients with complicated mTBI constitute a broad category encompassing individuals who may differ markedly in the nature and extent of intracranial imaging abnormality, and further studies are warranted. Limitations of the available studies include small, selected samples; variations in TBI severity classification; absence of validity ("effort") testing; differing imaging methodology; and lack of long-term follow-up.

Relationship satisfaction among spouse caregivers of service members and veterans with comorbid mild traumatic brain injury and post-traumatic stress disorder

This study examined relationship satisfaction and health-related quality of life (HRQOL) among spouse caregivers assisting service members and veterans (SMV) with comorbid uncomplicated mild traumatic brain injury (MTBI) and post-traumatic stress disorder (PTSD). Spouse caregivers (N = 205) completed the Couples Satisfaction Index (CSI), 12 HRQOL measures, and the Mayo-Portland Adaptability Inventory 4^th Edition (MPAI-4). T-scores were classified as "clinically elevated" using a cutoff of ≥60T. The sample was also classified into "Satisfied" (≥13.5, n = 113, 55.0%) or "Dissatisfied" (<13.5, n = 92, 44.0%) relationship categories. Using stepwise regression analysis, Anxiety, Family Disruption, Vigilance, Emotional Support, Feeling Trapped, and MPAI-4 Adjustment were identified as the strongest predictors of CSI total scores (p < 0.001), accounting for 41.6% of the variance. Squared semi-partial correlations revealed that 18.1% of the variance was shared across all six measures, with 7.8% to 1.5% of unique variance accounted for by each measure separately. When comparing the number of clinically elevated measures simultaneously, the Dissatisfied group consistently had a higher number of clinically elevated scores compared to the Satisfied group (e.g., 3-or-more clinically elevated scores: Dissatisfied = 40.2%, Satisfied = 8.8%, OR = 6.93, H = 0.76). Caring for a SMV with comorbid TBI and PTSD can have a profound impact on the spouse caregiver's HRQOL, relationship satisfaction, and family functioning. The findings from the current study continue to support the need for family involvement in the SMV's treatment plan, but more effort is needed to integrate behavioral health treatment that focuses on the family member's own issues into military TBI and PTSD systems of care.

Is Traumatic Brain Injury Severity in Service Members and Veterans Related to Health-Related Quality of Life in Their Caregivers?

OBJECTIVE

To examine the relationship between service member/veteran (SM/V) traumatic brain injury (TBI) severity with caregiver health-related quality of life (HRQOL).

SETTING

Military treatment facility.

PARTICIPANTS

Caregivers (N = 316) of SM/Vs following a TBI divided into 2 groups based on SM/V TBI severity: (1) caregivers of SM/Vs following an uncomplicated mild TBI (UnMTBI Caregiver group, n = 246), and (2) caregivers of SM//Vs following a complicated mild, moderate, severe, or penetrating TBI (STBI Caregiver group, n = 70). The STBI Caregiver group was further divided into 2 subgroups: Parent (n = 21) versus Intimate Partner (n = 49). The UnMTBI Caregiver group consisted of intimate partners.

DESIGN

Prospective cohort.

MAIN MEASURES

Caregivers completed 15 HRQOL measures.

RESULTS

Using analysis of variance and chi-square analysis, the UnMTBI Caregiver group reported worse scores on 12 HRQOL measures and more clinically elevated scores for 6 of 15 comparisons than the STBI Caregiver group. The UnMTBI Caregiver group also reported worse scores on 10 HRQOL measures than intimate partners in the STBI Caregiver group and 5 measures than parents in the STBI Caregiver group. Parents reported worse scores on 3 measures than intimate partners in the STBI Caregiver group. The UnMTBI Caregiver group reported more clinically elevated scores for 7 of 15 comparisons than intimate partners in the STBI Caregiver group.

CONCLUSION

Intimate partner caregivers of an SM/V following a remote uncomplicated MTBI reported worse HRQOL than intimate partners and parent caregivers of an SM/V following a more severe TBI, mostly likely due to SM/V physical and mental health comorbidities. Interventions that focus on the SM/V's TBI and other comorbidities, the caregiver's behavioral health problems, and the relationship and family factors that interact with each other will likely have the most success in improving individual and family outcomes for military families.

Aggression in Military Members With Mild Traumatic Brain Injury and Post-Traumatic Stress Disorder Is Associated With Intimate Partner Health-Related Quality of Life

OBJECTIVE

We aimed to examine the relationship between service member/veteran (SMV) aggression and health-related quality of life (HRQOL) in their intimate partners.

METHODS

This prospective cohort study included 201 female intimate partner caregivers of post-9/11 male SMVs with a diagnosis of uncomplicated mild traumatic brain injury and post-traumatic stress disorder from a military treatment facility. Caregivers completed 17 HRQOL measures and rated the level the SMV experiences problems with verbal or physical expressions of irritability, anger, or aggression on the Mayo-Portland Adaptability Inventory, 4th edition. Caregivers were classified into three SMV Aggression groups: i) none or very mild (n = 53); ii) mild (n = 47); and iii) moderate or severe (n = 101). HRQOL scores were classified as clinically elevated using a cutoff of 60T or higher.

RESULTS

Using χ² analysis, the moderate or severe group had a significantly higher proportion of clinically elevated scores on 15 HRQOL measures compared with the none or very mild group, and six measures compared with the mild group. The mild group had higher scores on two measures compared with the none or very mild group. Using analysis of covariance (and controlling for caregiver strain), the moderate or severe group had significantly higher scores on 11 HRQOL measures compared with the none or very mild group, and two measures compared with the mild group. The mild group had higher scores on five measures compared with the none or very mild group.

CONCLUSIONS

Many caregivers who report moderate to severe SMV aggression after a traumatic brain injury, report poor HRQOL beyond the strain of care provision. Traumatic brain injury and post-traumatic stress disorder programs should screen for and treat SMV aggression, and attend to the health needs of their caregivers.

Pain interference and health-related quality of life in caregivers of service members and veterans with traumatic brain injury and mental health comorbidity

PURPOSE

To examine (1) the relationship between caregiver pain interference with caregiver health-related quality of life (HRQOL), caregiver age, and service member/veteran (SMV) functional ability, and (2) change in caregiver pain interference longitudinally over 5 years.

METHOD

Participants were 347 caregivers of SMVs diagnosed with traumatic brain injury (TBI). Caregivers completed the SF-12v2 Health Survey Bodily Pain scale at an initial baseline evaluation and up to four annual follow-up evaluations. Caregivers were divided into three pain interference groups: High Pain Interference (n = 104), Neutral Pain Interference (n = 117), and Low Pain Interference (n = 126). Caregivers also completed 15 HRQOL measures and a measure of SMV functional ability.

RESULTS

The High Pain Interference group reported more clinically elevated scores on 13 measures compared to the Low Pain Interference group, and seven measures compared to the Neutral Pain Interference group. The Neutral Pain Interference group had more clinically elevated scores on three measures compared to the Low Pain Interference group. The High and Neutral Pain Interference groups were older than the Low Pain Interference group. Parent caregivers were older than intimate partner/sibling caregivers, but did not report worse pain interference. Caregiver age, and measures of Fatigue, Strain, Perceived Rejection, and Economic QOL were the strongest predictors of pain interference (p < .001), accounting for 28.2% of the variance. There was minimal change in Bodily Pain scores over five years. The interaction of time and age was not significant (X² = 2.7, p = .61).

CONCLUSION

It is important to examine pain in the context of HRQOL in caregivers, regardless of age.

Extracellular vesicle neurofilament light is elevated within the first 12-months following traumatic brain injury in a U.S military population

Traumatic brain injury (TBI) can be associated with long-term neurobehavioral symptoms. Here, we examined levels of neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) in extracellular vesicles isolated from blood, and their relationship with TBI severity and neurobehavioral symptom reporting. Participants were 218 service members and veterans who sustained uncomplicated mild TBIs (mTBI, n = 107); complicated mild, moderate, or severe TBIs (smcTBI, n = 66); or Injured controls (IC, orthopedic injury without TBI, n = 45). Within one year after injury, but not after, NfL was higher in the smcTBI group than mTBI (p = 0.001, d = 0.66) and IC (p = 0.001, d = 0.35) groups, which remained after controlling for demographics and injury characteristics. NfL also discriminated the smcTBI group from IC (AUC:77.5%, p < 0.001) and mTBI (AUC:76.1%, p < 0.001) groups. No other group differences were observed for NfL or GFAP at either timepoint. NfL correlated with post-concussion symptoms (rs = - 0.38, p = 0.04) in the mTBI group, and with PTSD symptoms in mTBI (rs = - 0.43, p = 0.021) and smcTBI groups (rs = - 0.40, p = 0.024) within one year after injury, which was not confirmed in regression models. Our results suggest the potential of NfL, a protein previously linked to axonal damage, as a diagnostic biomarker that distinguishes TBI severity within the first year after injury.

Neurocognitive and Affective Sequelae Following Complicated Mild and Moderate Traumatic Brain Injury: A Case Series

Background

Traumatic brain injury (TBI) leads to various sequelae that affect the day-to-day functioning of patients. However, there is a dearth of studies investigating these sequelae in complicated mild TBI and moderate TBI patients.

Objective

The prime objective of the present study was to present the neurocognitive and affective profile of complicated mild and moderate TBI patients along with to compare the neurocognitive and affective sequelae in patients with complicated mild and moderate TBI.

Materials and Methods

Twenty-two patients with complicated mild TBI and 17 patients with Moderate TBI, each with an intracranial lesion were recruited from level 1 trauma center in Varanasi. All patients were assessed with neurocognitive measures, Rivermead Post Concussive Symptoms Questionnaire, and Hospital Anxiety and Depression Scale. The patients' profiles were presented as clinical series using descriptive analysis. Further, comparison was done by using the Chi-square test and Fisher's exact test.

Results

Findings revealed that complicated mild TBI patients reported significantly higher psychological distress and post head injury symptoms in comparison to patients with moderate TBI. Further, the complicated mild TBI and moderate TBI groups showed differences with respect to verbal fluency, mental speed, and flexibility tasks.

Conclusions

Complicated mild TBI and moderate TBI groups have not differed significantly on most of the cognitive tasks. Furthermore, affective symptoms were found more prominent in complicated mild TBI group as compared to the moderate TBI group.

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.

Cross-sectional study of major procedure codes among hospitalized patients with traumatic brain injury by level of injury severity in the 2004 to 2014 Nationwide Inpatient Sample

Despite its public health significance, TBI management across US healthcare institutions and patient characteristics with an emphasis on utilization and outcomes of TBI-specific procedures have not been evaluated at the national level.We aimed to characterize top 10 procedure codes among hospitalized adults with TBI as primary diagnosis by injury severity.A Cross-sectional study was conducted using 546, 548 hospitalization records from the 2004 to 2014 Nationwide Inpatient Sample were analyzed.Data elements of interest included injury, patient, hospital characteristics, procedures, in-hospital death and length of stay.Ten top procedure codes were "Closure of skin and subcutaneous tissue of other sites", "Insertion of endotracheal tube", "Continuous invasive mechanical ventilation for less than 96 consecutive hours", "Venous catheterization (not elsewhere classified)", "Continuous invasive mechanical ventilation for 96 consecutive hours or more", "Transfusion of packed cells", "Incision of cerebral meninges", "Serum transfusion (not elsewhere classified)", "Temporary tracheostomy", and "Arterial catherization". Prevalence rates ranged between 3.1% and 15.5%, with variations according to injury severity and over time. Whereas "Closure of skin and subcutaneous tissue of other sites" was associated with fewer in-hospital deaths and shorter hospitalizations, "Temporary tracheostomy" was associated with fewer in-hospital deaths among moderate-to-severe TBI patients, and "Continuous invasive mechanical ventilation for less than 96 consecutive hours" was associated with shorter hospitalizations among severe TBI patients. Other procedures were associated with worse outcomes.Nationwide, the most frequently reported hospitalization procedure codes among TBI patients aimed at homeostatic stabilization and differed in prevalence, trends, and outcomes according to injury severity.

Clinical and Affective Correlates of Cognitive Functioning in Complicated Mild and Moderate Traumatic Brain Injury Patients Belonging to Rural Areas

Background/Objective  Mild and moderate traumatic brain injury (TBI) is a neglected field especially with reference to its association with cognitive, behavioral, and emotional sequelae. The present study aimed to investigate the association of affective symptoms and clinical factors with neurocognitive functioning in complicated mild and moderate TBI patients.

Materials and Methods  The sample comprised 39 complicated mild and moderate TBI patients with age range of 18 to 59 years. The study was conducted in the Department of Neurosurgery, Banaras Hindu University, Varanasi. The patients were assessed with the neurocognitive tests, Rivermead Post Concussion Symptom Questionnaire, and Hospital Anxiety and Depression Scale.

Statistical Analysis Partial correlations and zero order correlations were used to test the relationships between variables.

Results The injury-related factors, namely level of consciousness and Glasgow Coma Scale were found to be associated with divided attention and memory dysfunction ( p < 0.05), respectively. Anxiety was found to be associated with impairment on all domains of neurocognitive function ( p < 0.05) except divided attention. Depressive symptoms were found to be correlated with all the neurocognitive functions ( p < 0.05) except focused and divided attention, whereas head injury symptoms correlated with impairment on focused and divided attention ( p < 0.05).

Conclusion Present study highlights the need to acknowledge affective symptoms along with clinical factors in the planning of the rehabilitation programs for such patients in rural scenario.

Post-Traumatic Stress Disorder Is Associated with Neuropsychological Outcome but Not White Matter Integrity after Mild Traumatic Brain Injury

The aim of this study was to examine neuropsychological functioning and white matter integrity, in service members and veterans (SMVs) after mild traumatic brain injury (MTBI), with versus without post-traumatic stress disorder (PTSD). Participants were 116 U.S. military SMVs, prospectively enrolled from the Walter Reed National Military Medical Center (Bethesda, MD), who had sustained an MTBI (n = 86) or an injury without TBI (i.e., Injured Control [IC]; n = 30). Participants completed a battery of neuropsychological measures (neurobehavioral and -cognitive), as well as diffusion tensor imaging (DTI) of the brain, on average 6 years post-injury. Based on diagnostic criteria for PTSD, participants in the MTBI group were classified into two subgroups: MTBI/PTSD-Present (n = 21) and MTBI/PTSD-Absent (n = 65). Participants in the IC group were included only if they were classified as PTSD-Absent. The MTBI/PTSD-Present group had a significantly higher number of self-reported symptoms on all neurobehavioral measures (e.g., depression), and lower scores on more than half of the neurocognitive domains (e.g., processing speed), compared to the MTBI/PTSD-Absent and IC/PTSD-Absent groups. There were no significant group differences for the vast majority of DTI measures, with the exception of a handful of regions (i.e., superior longitudinal fascicle and superior thalamic radiation). These results suggest that there is 1) a strong relationship between PTSD and poor neuropsychological outcome after MTBI and 2) a lack of a relationship between PTSD and white matter integrity, as measured by DTI, after MTBI. Concurrent PTSD and MTBI should be considered a risk factor for poor neuropsychological outcome that requires early intervention.

Complicated versus uncomplicated mild traumatic brain injuries: A comparison of psychological, cognitive, and post-concussion symptom outcomes

INTRODUCTION

A complicated mild traumatic brain injury (MTBI) is defined as mild by all clinical severity indicators but is complicated due to a traumatic intracranial abnormality visible on neuroimaging. Researchers have reported mixed findings regarding whether neuropsychological and functional outcomes following complicated MTBI are worse than, or similar to, outcomes following uncomplicated MTBI. This study examined patients referred from a Taiwanese emergency department to a neurosurgical outpatient clinic. Participants with complicated MTBI, uncomplicated MTBI, and those who did not undergo head computed tomography (CT) were compared on psychological, neuropsychological, and post-concussion symptom outcomes within 21 days of injury.

METHOD

Participants with complicated MTBI (n = 42), uncomplicated MTBI (n = 77), and no head CT (n = 172) completed the Paced Auditory Serial Attention Test, Taiwanese Word Sequence Learning Test, a semantic Verbal Fluency Test, the Checklist of Post-Concussion Symptoms, and the Beck Depression and Anxiety Inventories.

RESULTS

No significant differences were observed between groups on any measure. For individual post-concussion symptoms, dizziness, anxiety, and attention difficulty were endorsed more often after uncomplicated MTBIs, but these group differences were not significant after controlling for multiple comparisons.

CONCLUSIONS

Participants with complicated MTBIs did not have worse acute or subacute outcomes than participants with uncomplicated MTBIs or no head CT. These results are consistent with many studies finding comparable outcomes between those with complicated and uncomplicated MTBIs. This study is limited by small sample size and minimal information on intracranial abnormalities, broadly categorizing groups based on positive or negative neuroimaging as opposed to specific lesion types and locations.

Risperidone versus placebo for aggression following traumatic brain injury: a feasibility randomised controlled trial

OBJECTIVES

To conduct a feasibility randomised controlled trial of risperidone for the treatment of aggression in adults with traumatic brain injury (TBI).

DESIGN

Multicentre, parallel design, placebo controlled (1:1 ratio) double-blind feasibility trial with an embedded process evaluation. No statistical comparison was performed between the two study groups.

SETTING

Four neuropsychiatric and neurology outpatient clinics in London and Kent, UK.

PARTICIPANTS

Our aim was to recruit 50 patients with TBI over 18 months. Follow-up participants at 12 weeks using a battery of assessment scales to measure changes in aggressive behaviour and irritability (Modified Overt Aggression Scale (MOAS)-primary outcome, Irritability Questionnaire) as well as global functioning (Glasgow Outcome Scale-Extended, Clinical Global impression) and quality of life (EQ-5D-5L, SF-12), mental health (Hospital Anxiety and Depression Scale) and medication adverse effects (Udvalg for Kliniske Undersøgelser).

RESULTS

Six participants were randomised to the active arm of the trial and eight to the placebo arm over a 10-month period (28% of our target). Two participants withdrew because of adverse events. Twelve out of 14 (85.7%) patients completed a follow-up assessment at 12 weeks. At follow-up, the scores of all outcome measures improved in both groups. Placebo group showed numerically better score change according to the primary outcome MOAS. No severe adverse events were reported. The overall rate of adverse events remained low. Data from the process evaluation suggest that existence of specialised TBI follow-up clinics, availability of a dedicated database of TBI patients' clinical details, simple study procedures and regular support to participants would enhance recruitment and retention in the trial. Feedback from participants showed that once in the study, they did not find the trial procedure onerous.

CONCLUSIONS

It was not feasible to conduct a successful randomised trial of risperidone versus placebo for post-TBI aggression using the methods we deployed in this study. It is not possible to draw any definitive conclusion about risperidone's efficacy from such a small trial.

TRIAL REGISTRATION NUMBER

ISRCTN30191436.

Psychological predictors of functional outcomes in service members with traumatic brain injury

PRIMARY OBJECTIVE

Research is increasingly demonstrating the significant impact that non-medical factors can have on outcomes of service members (SMs) with mild traumatic brain injury (mTBI). Thus, the current study examined which demographic, TBI-related factors, and psychological variables are most predictive of functional outcomes.

RESEARCH DESIGN

Retrospective database analysis from medical chart review.

METHODS AND PROCEDURES

One hundred forty-one patients who received rehabilitation services at an outpatient TBI military treatment facility between 2013 and 2018. Data collected included demographic variables, time since injury, neuropsychological measures, psychological diagnoses, Personality Assessment Inventory (PAI) scores, and Walter Reed Functional Impairment Scale (FIS). Hierarchical linear regression models were used to predict functional outcomes (measured by FIS total, work, social functioning scales).

MAIN OUTCOMES AND RESULTS

Results indicated that comorbid PTSD diagnosis and PAI Negative Impression Management (NIM) score were predictive of total functional, work, and social outcomes, over and above demographic and TBI-related factors.

CONCLUSIONS

Current findings confirmed the importance of evaluating and treating psychological factors, as well as exploring one's responding style (NIM), when managing chronic mTBI in SMs. Given ongoing findings of psychological underpinnings to mTBI outcome, there is further need to focus on early interventions to optimize psychological and functional outcomes for SMs.

Two latent classes of diagnostic and treatment procedures among traumatic brain injury inpatients

To characterize latent classes of diagnostic and/or treatment procedures among hospitalized U.S. adults, 18-64 years, with primary diagnosis of TBI from 2004-2014 Nationwide Inpatient Samples, latent class analysis (LCA) was applied to 10 procedure groups and differences between latent classes on injury, patient, hospital and healthcare utilization outcome characteristics were modeled using multivariable regression. Using 266,586 eligible records, LCA resulted in two classes of hospitalizations, namely, class I (n = 217,988) (mostly non-surgical) and class II (n = 48,598) (mostly surgical). Whereas orthopedic procedures were equally likely among latent classes, skin-related, physical medicine and rehabilitation procedures as well as behavioral health procedures were more likely among class I, and other types of procedures were more likely among class II. Class II patients were more likely to have moderate-to-severe TBI, to be admitted on weekends, to urban, medium-to-large hospitals in Midwestern, Southern or Western regions, and less likely to be > 30 years, female or non-White. Class II patients were also less likely to be discharged home and necessitated longer hospital stays and greater hospitalization charges. Surgery appears to distinguish two classes of hospitalized patients with TBI with divergent healthcare needs, informing the planning of healthcare services in this target population.

Posttraumatic Stress Disorder is a Stronger Predictor of Long-Term Neurobehavioral Outcomes Than Traumatic Brain Injury Severity

Concurrent posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI) is common in military populations. The purpose of this study was to examine long-term neurobehavioral outcomes in service members and veterans (SMVs) with versus without PTSD symptoms following TBI of all severities. Participants were 536 SMVs prospectively enrolled from three military medical treatment facilities who were recruited into three experimental groups: TBI, injured controls (IC), and noninjured controls (NIC). Participants completed the PTSD Checklist, Neurobehavioral Symptom Inventory, and the TBI-Quality of Life (TBI-QOL) and were divided into six subgroups based on the three experimental categories, two PTSD categories (i.e., present vs. absent), and two broad TBI severity categories (unMTBI, which included uncomplicated mild TBI; and smcTBI, which included severe TBI, moderate TBI, and complicated mild TBI): (a) NIC/PTSD-absent, (b) IC/PTSD-absent, (c) unMTBI/PTSD-absent, (d) unMTBI/PTSD-present, (e) smcTBI/PTSD-absent, and (f) smcTBI/PTSD-present. There were significant main effects across the six groups for all TBI-QOL measures, ps < .001. Select pairwise comparisons revealed significantly lower scores, p < .001, on all TBI-QOL measures in the PTSD-present groups when compared to the PTSD-absent groups within the same TBI severity classification, ds = 0.90-2.11. In contrast, when controlling for PTSD, there were no significant differences among the TBI severity groups for any TBI-QOL measures. These results provide support for the strong influence of PTSD but not TBI severity on neurobehavioral outcomes following TBI. Concurrent PTSD and TBI of all severities should be considered a risk factor for poor long-term neurobehavioral outcomes that require ongoing monitoring.

Electrophysiological Markers of Visuospatial Attention Recovery after Mild Traumatic Brain Injury

Objective: Attentional problems are amongst the most commonly reported complaints following mild traumatic brain injury (mTBI), including difficulties orienting and disengaging attention, sustaining it over time, and dividing attentional resources across multiple simultaneous demands. The objective of this study was to track, using a single novel electrophysiological task, various components associated with the deployment of visuospatial selective attention. Methods: A paradigm was designed to evoke earlier visual evoked potentials (VEPs), as well as attention-related and visuocognitive ERPs. Data from 36 individuals with mTBI (19 subacute, 17 chronic) and 22 uninjured controls are presented. Postconcussion symptoms (PCS), anxiety (BAI), depression (BDI-II) and visual attention (TEA Map Search, DKEFS Trail Making Test) were also assessed. Results: Earlier VEPs (P1, N1), as well as processes related to visuospatial orientation (N2pc) and encoding in visual short-term memory (SPCN), appear comparable in mTBI and control participants. However, there appears to be a disruption in the spatiotemporal dynamics of attention (N2pc-Ptc, P2) in subacute mTBI, which recovers within six months. This is also reflected in altered neuropsychological performance (information processing speed, attentional shifting). Furthermore, orientation of attention (P3a) and working memory processes (P3b) are also affected and remain as such in the chronic post-mTBI period, in co-occurrence with persisting postconcussion symptomatology. Conclusions: This study adds original findings indicating that such a sensitive and rigorous ERP task implemented at diagnostic and follow-up levels could allow for the identification of subtle but complex brain activation and connectivity deficits that can occur following mTBI.

Language Comprehension After Mild Traumatic Brain Injury: The Role of Speed

Purpose The aim of this study was to characterize language comprehension in mild traumatic brain injury (mTBI) by testing a speed-based hypothesis. We hypothesized that adults with mTBI would perform worse than a group of adults with orthopedic injuries (OIs) on an experimental language comprehension task. Method The study employed a prospective experimental design. Participants were 19 adults with mTBI and 19 adults with OI ages 18-55 years. Participants completed the Whatdunit task, a sentence agent selection task in speeded and unspeeded conditions. Results In the unspeeded condition, the mTBI group performed with a marginally significant higher accuracy than the OI group. In the speeded condition, the mTBI group performed with lower accuracy than the OI group; however, this difference did not reach statistical significance. There was a marginally significant interaction of Sentence Type × Group for reaction time in the speeded condition. Conclusions While our task might have been sensitive to cognitive processing abilities in both groups (as evidenced by the main effects of condition and sentence type), the task was not specific enough to capture mTBI-related deficits. The similarities in performance between both groups have clinical implications for the treatment of not just brain-related trauma but also trauma in general.

Rey Tangled Line Test: A measure of processing speed in TBI

OBJECTIVE

Neuropsychological assessment plays a key role in characterizing and detecting cognitive impairment after traumatic brain injury (TBI). The Rey Tangled Line Test (RTLT), an understudied neuropsychological assessment thought to be capable of detecting visual processing deficits, was examined to determine which cognitive abilities may contribute to performance on the test in participants with a history of TBI.

METHOD

One-hundred participants with a history of mild to severe TBI were administered a battery of neuropsychological tests assessing attention, executive functioning, memory, visual construction, motor functioning, and processing speed between 30 days and 5 years postinjury. An exploratory principal components analysis (PCA) was performed to determine which cognitive tests the RTLT was most highly associated with.

RESULTS

No difference in RTLT latency was present between mild and moderate/severe TBI. The PCA resulted in 5 factors. RTLT latency had a significant primary factor loading on the "processing speed" factor, and a secondary loading on the "motor" factor. Forty-two percent of participants had an impaired latency score.

CONCLUSIONS

RTLT latency appears to measure processing speed, and likely aspects of motor functioning, in our sample. The RTLT may be useful as a rapid assessment in individuals with a history of TBI to detect cognitive deficit before initiating further cognitive testing or rehabilitation efforts. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Results of scoping review do not support mild traumatic brain injury being associated with a high incidence of chronic cognitive impairment: Commentary on McInnes et al. 2017

A recently published review of 45 studies concluded that approximately half of individuals who sustain a single mild traumatic brain injury (MTBI) experience long-term cognitive impairment (McInnes et al. Mild Traumatic Brain Injury (mTBI) and chronic cognitive impairment: A scoping review. PLoS ONE 2017;12:e0174847). Stratified by age, they reported that 50% of children and 58% of adults showed some form of cognitive impairment. We contend that the McInnes et al. review used a definition of “cognitive impairment” that was idiosyncratic, not applicable to individual patients or subjects, inconsistent with how cognitive impairment is defined in clinical practice and research, and resulted in a large number of false positive cases of cognitive impairment. For example, if a study reported a statistically significant difference on a single cognitive test, the authors concluded that every subject with a MTBI in that study was cognitively impaired–an approach that cannot be justified statistically or psychometrically. The authors concluded that impairment was present in various cognitive domains, such as attention, memory, and executive functioning, but they did not analyze or report the results from any of these specific cognitive domains. Moreover, their analyses and conclusions regarding many published studies contradicted the interpretations provided by the original authors of those studies. We re-reviewed all 45 studies and extracted the main conclusions from each. We conclude that a single MTBI is not associated with a high incidence of chronic cognitive impairment.

Validity and reliability of the Neuropsychological Assessment Battery - Screening Module (S-NAB) in a subset of Malaysian population with mild traumatic brain injury (mTBI)

This study assessed the validity (construct validity) and reliability (internal consistency) of the Neuropsychological Assessment Battery Screening Module (S-NAB) in detecting mild cognitive deficit/alteration in multicultural, multilingual, and multiethnic mild traumatic brain injury (mTBI) population of Malaysia. S-NAB and Montreal Cognitive Assessment (MoCA) data from 114 patients with mTBI (93 males; 21 females) aged 18 to 60 years old were obtained at University Malaya Medical Center, Malaysia. The mean age was 28.17 ± 8.57 years and mean education years was 12.40 ± 2.01. Convergent validity was assessed between S-NAB domain scores and MoCA total scores by using Pearson's correlation and internal consistency was assessed using Cronbach's alpha. Acceptable internal consistency (α ≥ .70) was found for Attention, Language, and Memory domains but weak internal consistencies (α < .50) were found for Spatial and Executive Function domains. There were positive but weak correlations between S-NAB and MoCA. These findings provide some support for the application of S-NAB in assessing mild cognitive deficits of mTBI population in a Malaysian setting.

Medical Evaluation Board Involvement, Non-Credible Cognitive Testing, and Emotional Response Bias in Concussed Service Members

Introduction

Military Service Members (SMs) with post-concussive symptoms are commonly referred for further evaluation and possible treatment to Department of Defense Traumatic Brain Injury Clinics where neuropsychological screening/evaluations are being conducted. Understudied to date, the base rates of noncredible task engagement/performance validity testing (PVT) during cognitive screening/evaluations in military settings appears to be high. The current study objectives are to: (1) examine the base rates of noncredible PVTs of SMs undergoing routine clinical or Medical Evaluation Board (MEB) related workups using multiple objective performance-based indicators; (2) determine whether involvement in MEB is associated with PVT or symptom exaggeration/symptom validity testing (SVT) results; (3) elucidate which psychiatric symptoms are associated with noncredible PVT performances; and (4) determine whether MEB participation moderates the relationship between psychological symptom exaggeration and whether or not SM goes on to demonstrate PVTs failures - or vice versa.

Materials and Methods

Retrospective study of 71 consecutive military concussion cases drawn from a DoD TBI Clinic neuropsychology clinic database. As part of neuropsychological evaluations, patients completed several objective performance-based PVTs and SVT.

Results

Mean (SD) age of SMs was 36.0 (9.5), ranging from 19-59, and 93% of the sample was male. The self-identified ethnicity resulted in the following percentages: 62% Non-Hispanic White, 22.5% African American, and 15.5% Hispanic or Latino. The majority of the sample (97%) was Active Duty Army and 51% were involved in the MEB at the time of evaluation. About one-third (35.9%) of routine clinical patients demonstrated failure on one or more PVT indicators (12.8% failed 2) while PVT failure rates amongst MEB patients ranged from 15.6% to 37.5% (i.e., failed 2 or 1 PVTs, respectively). Base rates of failures on one or more PVT did not differ between routine clinical versus MEB patients (p = 0.94). MEB involvement was not associated with increased emotional symptom response bias as compared to routine clinical patients. PVT failures were positively correlated with somatization, anxiety, depressive symptoms, suspicious and hostility, atypical perceptions/alienation/subjective cognitive difficulties, borderline personality traits/features, and penchant for aggression in addition to symptom over-endorsement/exaggeration. No differences between routine clinical and MEB patients across other SVT indicators were found. MEB status did not moderate the relationship between any of the SVTs.

Conclusion

Study results are broadly consistent with the prior published studies that documented low to moderately high base rates of noncredible task engagement during neuropsychological evaluations in military and veteran settings. Results are in contrast to prior studies that have suggested involvement in MEB is associated with increased likelihood of poor PVT performances. This is the first to show that MEB involvement did not enhance/strengthen the association between PVT performances and evidence of SVTs. Consistent with prior studies, these results do highlight that the same SMs who fail PVTs also tend to be the ones who go on to endorse a myriad of psychiatric symptoms and proclivities. Implications of variable or poor task engagement during routine clinical and MEB neuropsychological evaluation in military settings on treatment and disposition planning cannot be overstated.

Neuroanatomical and functional alterations of insula in mild traumatic brain injury patients at the acute stage

Cognitive impairment is a major cause of disability and decline in quality of life in mild traumatic brain injury (mTBI) survivors, but the underlying pathophysiology is still poorly understood. The insula has extensive connections to other cortex and is believed to responsible for integrating external and internal processes and controlling cognitive functions. To explore this hypothesis, we investigated early alterations in the gray matter volume (GMV) and brain functional connectivity (FC) of insula in mTBI patients within 7 days after injury and any possible correlations with cognitive function. A total of 58 mTBI patients at the acute stage and 32 matched healthy controls were recruited and underwentT1-weighted magnetic resonance imaging (MRI)andresting-state functional MRI scans within 7 days of injury. FC was characterized using seed-based region of interest analysis method. The patients' cognitive function was evaluated with Montreal Cognitive Assessment (MoCA) score. The resulting of GMV and FC of insula were correlated with cognitive alterations. We found that the GMV was significantly reduced only in the right insula in mTBI patients and no significant GMV increase was observed in either hemisphere. mTBI patients demonstrated decreased FC in the right parahippocampal gyrus and increased FC in the right supramargianl gyrus. In addition, compared to the healthy controls, the mTBI patients in the acute stage presented a decline in the visuospatial/executive (p = 0.013) and attention (p = 0.038) subcategories. In the mTBI group, the changes in GMV in the right insula were positively correlated with poor attention performance (r = 0.316, p = 0.016). Our data demonstrated alterations of the GMV and resting-stateFC of the right insula in mTBI patients at the acute stage. These early changes in GMV and resting-state FC perhaps serve as a potential biomarker for improving the understanding of cognitive decline for mTBI in the acute setting.

Duration of Posttraumatic Amnesia Predicts Neuropsychological and Global Outcome in Complicated Mild Traumatic Brain Injury

OBJECTIVES

Examine the effects of posttraumatic amnesia (PTA) duration on neuropsychological and global recovery from 1 to 6 months after complicated mild traumatic brain injury (cmTBI).

PARTICIPANTS

A total of 330 persons with cmTBI defined as Glasgow Coma Scale score of 13 to 15 in emergency department, with well-defined abnormalities on neuroimaging.

METHODS

Enrollment within 24 hours of injury with follow-up at 1, 3, and 6 months.

MEASURES

Glasgow Outcome Scale-Extended, California Verbal Learning Test II, and Controlled Oral Word Association Test. Duration of PTA was retrospectively measured with structured interview at 30 days postinjury.

RESULTS

Despite all having a Glasgow Coma Scale Score of 13 to 15, a quarter of the sample had a PTA duration of greater than 7 days; half had PTA duration of 1 of 7 days. Both cognitive performance and Extended Glasgow Outcome Scale outcomes were strongly associated with time since injury and PTA duration, with those with PTA duration of greater than 1 week showing residual moderate disability at 6-month assessment.

CONCLUSIONS

Findings reinforce importance of careful measurement of duration of PTA to refine outcome prediction and allocation of resources to those with cmTBI. Future research would benefit from standardization in computed tomographic criteria and use of severity indices beyond Glasgow Coma Scale to characterize cmTBI.

Analysis of Story Recall in Military Veterans With and Without Mild Traumatic Brain Injury: Preliminary Results

PURPOSE

The purpose of this study was to determine whether detailed analysis of story recall performance reveals significant differences between veterans with and without history of mild traumatic brain injury (mTBI).

METHOD

Twenty-one military veterans participated, with 7 reporting history of mTBI. All participants were administered the Logical Memory I and II subtests from the Wechsler Memory Scale-Fourth Edition (Wechsler, 2009). Responses were scored for total correct ideas (TCI) and total words produced (TWP).

RESULTS

Although the groups did not differ in scaled scores, other measures did reveal significant differences. After a delay, the mTBI group showed a greater drop in TCI relative to the control group. Additionally, the control group showed an increase in TWP when the recall was delayed versus immediate; a pattern not observed for the mTBI group.

CONCLUSIONS

The mTBI and control groups did not significantly differ in scaled scores. However, group differences were observed in TCI and TWP. The findings suggest that, relative to the control group, the mTBI group were less successful in retrieving episodic information and eliciting self-cueing. Small sample size limited data interpretation, and larger sample sizes are needed to confirm the findings. The results indicate that veterans with mTBI may present with symptoms persisting beyond the acute state of the injury.

Enhancing attention in neurodegenerative diseases: current therapies and future directions

We all experience at least occasional lapses in attention but in some neurological conditions, loss of attention is pervasive and debilitating. Treating deficits in attention first requires an understanding of the neurobiology of attention, which we now understand to be a set of different cognitive processes. Cholinesterase inhibitors are already established as effective attentional enhancers used in the treatment of certain dementias. Other stimulant agents such as modafanil, amphetamine and methylphenidate have demonstrated limited success in healthy individuals where attention is already optimal and clinical trials in patients with neurological disease are sparse. Dietary and lifestyle changes are gaining increasing prominence, as are experimental treatments such as deep brain stimulation and transcranial magnetic stimulation. As the therapeutic arsenal widens, clinicians will be able to match specific treatments to selective deficits in attention, giving patients a tailored management plan. Here we review common diseases that impair attention and emphasise how an understanding of attentional processing within the brain might lead to improved therapeutic strategies.

Impact of pre-injury family functioning and resources on self-reported post-concussive symptoms and functional outcomes in persons with mild TBI

OBJECTIVE

This study investigates the contribution of pre-injury family functioning and resources on self-reported post-concussive symptoms and functional outcomes in persons with mild TBI (mTBI).

DESIGN

Participants with uncomplicated or complicated mTBIs were recruited from consecutive admissions to the emergency department of a level 1 trauma centre. Patients completed baseline assessments within 2 weeks of injury and an outcomes assessment at 3 months post-injury.

METHODS AND PROCEDURES

One hundred and sixty-six adults with mTBI were included. Baseline measures of pre-injury history, family functioning and resources were obtained. Functional status assessments and self-reported measures of health, common TBI symptoms and psychological problems were administered at 3-months post-injury.

RESULTS

Data reduction of outcome measures using principle components analysis revealed two factors: self-reported post-concussive symptoms and current functional/participation status, explaining 60.53% of the variance. Family resources (β = -0.239, t(150) = -2.84, p = 0.005) and age (β = -0.170, t(150) = -2.19, p = 0.030), but not family functioning, were significant predictors of self-reported post-concussive symptoms at follow-up, R² = 0.051, F(5, 150) = 4.09, p = 0.002. Neither family resources nor functioning predicted current functional/participation status.

CONCLUSIONS

Fewer family resources and younger age were associated with increased self-reported post-concussive symptoms. Fewer resources may be a potential risk factor to heightened perception of post-concussive symptoms. Providing low-cost counselling or resource facilitation services may improve outcomes for those with limited resources after mTBI.

The experience, expression, and control of anger following traumatic brain injury in a military sample

OBJECTIVE

To investigate the impact of traumatic brain injury (TBI) on the experience and expression of anger in a military sample.

PARTICIPANTS

A total of 661 military personnel with a history of TBI and 1204 military personnel with no history of TBI.

DESIGN

Cross-sectional, between-group design, using multivariate analysis of variance.

MAIN MEASURE

State-Trait Anger Expression Inventory-2 (STAXI-2).

RESULTS

Participants with a history of TBI had higher scores on the STAXI-2 than controls and were 2 to 3 times more likely than the participants in the control group to have at least 1 clinically significant elevation on the STAXI-2. Results suggested that greater time since injury (ie, months between TBI and assessment) was associated with lower scores on the STAXI-2 State Anger scale.

CONCLUSION

Although the results do not take into account confounding psychiatric conditions and cannot address causality, they suggest that a history of TBI increases the risk of problems with the experience, expression, and control of anger. This bolsters the need for proper assessment of anger when evaluating TBI in a military cohort.

Neuropsychological outcome and diffusion tensor imaging in complicated versus uncomplicated mild traumatic brain injury

This study examined whether intracranial neuroimaging abnormalities in those with mild traumatic brain injury (MTBI) (i.e., “complicated” MTBIs) are associated with worse subacute outcomes as measured by cognitive testing, symptom ratings, and/or diffusion tensor imaging (DTI). We hypothesized that (i) as a group, participants with complicated MTBIs would report greater symptoms and have worse neurocognitive outcomes than those with uncomplicated MTBI, and (ii) as a group, participants with complicated MTBIs would show more Diffusion Tensor Imaging (DTI) abnormalities. Participants were 62 adults with MTBIs (31 complicated and 31 uncomplicated) who completed neurocognitive testing, symptom ratings, and DTI on a 3T MRI scanner approximately 6-8 weeks post injury. There were no statistically significant differences between groups on symptom ratings or on a broad range of neuropsychological tests. When comparing the groups using tract-based spatial statistics for DTI, no significant difference was found for axial diffusivity or mean diffusivity. However, several brain regions demonstrated increased radial diffusivity (purported to measure myelin integrity), and decreased fractional anisotropy in the complicated group compared with the uncomplicated group. Finally, when we extended the DTI analysis, using a multivariate atlas based approach, to 32 orthopedic trauma controls (TC), the findings did not reveal significantly more areas of abnormal DTI signal in the complicated vs. uncomplicated groups, although both MTBI groups had a greater number of areas with increased radial diffusivity compared with the trauma controls. This study illustrates that macrostructural neuroimaging changes following MTBI are associated with measurable changes in DTI signal. Of note, however, the division of MTBI into complicated and uncomplicated subtypes did not predict worse clinical outcome at 6-8 weeks post injury.

Cognitive changes and dementia risk after traumatic brain injury: implications for aging military personnel

Traumatic brain injury (TBI) is recognized as an important risk factor for the long-term cognitive health of military personnel, particularly in light of growing evidence that TBI increases risk for Alzheimer's disease and other dementias. In this article, we review the neurocognitive and neuropathologic changes after TBI with particular focus on the potential risk for cognitive decline across the life span in military service members. Implications for monitoring and surveillance of cognition in the aging military population are discussed. Additional studies are needed to clarify the factors that increase risk for later life cognitive decline, define the mechanistic link between these factors and dementia, and provide empirically supported interventions to mitigate the impact of TBI on cognition across the life span.

Effects of low-level blast exposure on the nervous system: is there really a controversy?

High-pressure blast waves can cause extensive CNS injury in human beings. However, in combat settings, such as Iraq and Afghanistan, lower level exposures associated with mild traumatic brain injury (mTBI) or subclinical exposure have been much more common. Yet controversy exists concerning what traits can be attributed to low-level blast, in large part due to the difficulty of distinguishing blast-related mTBI from post-traumatic stress disorder (PTSD). We describe how TBI is defined in human beings and the problems posed in using current definitions to recognize blast-related mTBI. We next consider the problem of applying definitions of human mTBI to animal models, in particular that TBI severity in human beings is defined in relation to alteration of consciousness at the time of injury, which typically cannot be assessed in animals. However, based on outcome assessments, a condition of "low-level" blast exposure can be defined in animals that likely approximates human mTBI or subclinical exposure. We review blast injury modeling in animals noting that inconsistencies in experimental approach have contributed to uncertainty over the effects of low-level blast. Yet, animal studies show that low-level blast pressure waves are transmitted to the brain. In brain, low-level blast exposures cause behavioral, biochemical, pathological, and physiological effects on the nervous system including the induction of PTSD-related behavioral traits in the absence of a psychological stressor. We review the relationship of blast exposure to chronic neurodegenerative diseases noting the paradoxical lowering of Abeta by blast, which along with other observations suggest that blast-related TBI is pathophysiologically distinct from non-blast TBI. Human neuroimaging studies show that blast-related mTBI is associated with a variety of chronic effects that are unlikely to be explained by co-morbid PTSD. We conclude that abundant evidence supports low-level blast as having long-term effects on the nervous system.

Emotional and behavioral dyscontrol after traumatic brain injury

Emotional and behavioral dyscontrol are relatively common neuropsychiatric sequelae of traumatic brain injury and present substantial challenges to recovery and community participation. Among the most problematic and functionally disruptive of these types of behaviors are pathologic laughing and crying, affective lability, irritability, disinhibition, and aggression. Managing these problems effectively requires an understanding of their phenomenology, epidemiology, and clinical evaluation. This article reviews these issues and provides clinicians with brief and practical suggestions for the management of emotional and behavioral dyscontrol.

Neuroimaging biomarkers in mild traumatic brain injury (mTBI)

Reviewed herein are contemporary neuroimaging methods that detect abnormalities associated with mild traumatic brain injury (mTBI). Despite advances in demonstrating underlying neuropathology in a subset of individuals who sustain mTBI, considerable disagreement persists in neuropsychology about mTBI outcome and metrics for evaluation. This review outlines a thesis for the select use of sensitive neuroimaging methods as potential biomarkers of brain injury recognizing that the majority of individuals who sustain an mTBI recover without neuroimaging signs or neuropsychological sequelae detected with methods currently applied. Magnetic resonance imaging (MRI) provides several measures that could serve as mTBI biomarkers including the detection of hemosiderin and white matter abnormalities, assessment of white matter integrity derived from diffusion tensor imaging (DTI), and quantitative measures that directly assess neuroanatomy. Improved prediction of neuropsychological outcomes in mTBI may be achieved with the use of targeted neuroimaging markers.

Meta-analytic methods and the importance of non-TBI factors related to outcome in mild traumatic brain injury: response to Bigler et al. (2013)

Bigler et al. (2013, The Clinical Neuropsychologist) contend that weak methodology and poor quality of the studies comprising our recent meta-analysis led us to miss detecting a subgroup of mild traumatic brain injury (mTBI) characterized by persisting symptomatic complaint and positive biomarkers for neurological damage. Our computation of non-significant Q, tau(2), and I(2) statistics contradicts the existence of a subgroup of mTBI with poor outcome, or variation in effect size as a function of quality of research design. Consistent with this conclusion, the largest single contributor to our meta-analysis, Dikmen, Machamer, Winn, and Temkin (1995, Neuropsychology, 9, 80) yielded an effect size, -0.02, that was smaller than our overall effect size of -0.07 despite using the most liberal definition of mTBI: loss of consciousness less than 1 hour, with no exclusion of subjects who had positive CT scans. The evidence is weak for biomarkers of mTBI, such as diffusion tensor imaging and for demonstrable neuropathology in uncomplicated mTBI. Postconcussive symptoms, and reduced neuropsychological test scores are not specific to mTBI but can result from pre-existing psychosocial and psychiatric problems, expectancy effects and diagnosis threat. Moreover, neuropsychological impairment is seen in a variety of primary psychiatric disorders, which themselves are predictive of persistent complaints following mTBI. We urge use of prospective studies with orthopedic trauma controls in future investigations of mTBI to control for these confounding factors.