A Meta-Analysis of Neuropsychological Outcome After Mild Traumatic Brain Injury: Re-analyses and Reconsiderations of Binder et al. (1997), Frencham et al. (2005), and Pertab et al. (2009)

Distinct trajectories of neuropsychiatric symptoms in the 12 months following traumatic brain injury (TBI): a TRACK-TBI study

BACKGROUND

Neuropsychiatric symptoms are common after traumatic brain injury (TBI) and often resolve within 3 months post-injury. However, the degree to which individual patients follow this course is unknown. We characterized trajectories of neuropsychiatric symptoms over 12 months post-TBI. We hypothesized that a substantial proportion of individuals would display trajectories distinct from the group-average course, with some exhibiting less favorable courses.

METHODS

Participants were level 1 trauma center patients with TBI (n = 1943), orthopedic trauma controls (n = 257), and non-injured friend controls (n = 300). Trajectories of six symptom dimensions (Depression, Anxiety, Fear, Sleep, Physical, and Pain) were identified using growth mixture modeling from 2 weeks to 12 months post-injury.

RESULTS

Depression, Anxiety, Fear, and Physical symptoms displayed three trajectories: Stable-Low (86.2-88.6%), Worsening (5.6-10.9%), and Improving (2.6-6.4%). Among symptomatic trajectories (Worsening, Improving), lower-severity TBI was associated with higher prevalence of elevated symptoms at 2 weeks that steadily resolved over 12 months compared to all other groups, whereas higher-severity TBI was associated with higher prevalence of symptoms that gradually worsened from 3-12 months. Sleep and Pain displayed more variable recovery courses, and the most common trajectory entailed an average level of problems that remained stable over time (Stable-Average; 46.7-82.6%). Symptomatic Sleep and Pain trajectories (Stable-Average, Improving) were more common in traumatically injured groups.

CONCLUSIONS

Findings illustrate the nature and rates of distinct neuropsychiatric symptom trajectories and their relationship to traumatic injuries. Providers may use these results as a referent for gauging typical v. atypical recovery in the first 12 months post-injury.

Cognitive profiles in the acute phase of traumatic brain injury according to injury severity

Although several studies have documented the chronic phase of traumatic brain injury (TBI), few verified the nature and severity of cognitive impairments during the acute phase. Among the studies carried out during the acute phase, instrumental functions were rarely examined compared to attention, memory, and executive functions. This study aimed to compare the nature and intensity of cognitive problems in the acute phase according to TBI severity and age. It was hypothesized that cognitive impairments would increase in line with TBI severity and age, and that instrumental functions would be less affected in victims of mild or moderate TBI than in those with severe TBI. The Brief Cognitive Exam in Traumatology (EXACT), a new and reliable test specifically designed and validated to briefly assess global cognitive functioning during the acute phase, was administered to 319 mild to severe TBI victims (aged 16 to 96 years), within three months post-accident. The EXACT evaluates five domains: Language, Instrumental functions (other than language), Attention and working memory, Episodic memory, and Executive functions and behavioral regulation. Results confirmed the negative influence of TBI severity and age on global cognitive functioning. Also, compared to victims with a mild or moderate TBI, a higher proportion of those with a severe TBI presented impaired instrumental functions (calculation, praxis, and gnosis). Thus, during the acute phase, the nature and severity of cognitive impairments vary according to TBI severity.

Long-term cognitive and affective consequences of mild traumatic brain injury: comparison with older adults

OBJECTIVE

Memory and affective processing were compared in young adults with a remote mild traumatic brain injury (mTBI), to healthy younger and older adults. We evaluated memory performance when encoding was done under multi-tasking (divided attention) conditions, likely to exacerbate cognitive and psychological symptoms in mTBI.

METHODS

Participants studied pairs of unrelated words under either full or divided attention conditions. Memory for single words (item memory) and for pairs of words (associative memory) was then assessed in sequential independent recognition tests, under full attention.

RESULTS

Associative memory was poorer than item memory, and worse when encoding was done under divided than full attention. The decline in recognition accuracy from full to divided attention conditions on the associative memory test was significantly greater in mTBI compared to young adults and was similar in magnitude to that observed in older adults under full attention. Self-reported mental and total fatigue increased significantly as performance on the memory tests, following the divided attention condition, decreased, but only in the mTBI group.

CONCLUSIONS

Results show lingering memory deficits, and suggest that cognitive tasks may be experienced as psychologically more demanding in those with a mTBI, even months or years after injury.

Emotional functioning in long COVID: Comparison to post-concussion syndrome using the Personality Assessment Inventory

Objective: Recent studies on Long COVID found that patients report prominent emotional distress and significant correlations between distress and cognitive performance have been identified, raising the question of how to manage or treat these issues. To understand psychological functioning in Long COVID further, this study examined personality responses on the Personality Assessment Inventory (PAI) to compare psychological functioning in a Long COVID group with a post-concussion syndrome (PCS) group, a syndrome with a significant psychological component. Participants and methods: Participants included 201 consecutive Long COVID outpatients (Mean age = 48.87 years, mean education = 14.82, 71.6% Female, 82.6% White) and a comparison group of 102 consecutively referred PCS outpatients (Mean age = 46.08, mean education = 14.17, 63.7% Female, 88.2% White). Effect sizes and t-tests were calculated using the PAI validity, clinical, interpersonal, and treatment consideration scales as well as clinical subscales. Results: The results replicated earlier findings on the PAI in Long COVID by demonstrating that both Long COVID and PCS groups had the highest mean elevations on SOM and DEP scales but no statistically significant between group differences in mean scale elevations. Results support similarities in psychological functioning between Long COVID and PCS patients emphasizing the importance of evaluating psychological functioning in neuropsychological evaluations for these populations. Further, results suggest that psychological treatment strategies for PCS patients may be helpful for Long COVID patients, but more research is needed.

Cross-validation of the Trail Making Test as a non-memory-based embedded performance validity test among veterans with and without cognitive impairment

OBJECTIVE

This study cross-validated multiple Trail Making Test (TMT) Parts A and B scores as non-memory-based embedded performance validity tests (PVTs) for detecting invalid neuropsychological performance among veterans with and without cognitive impairment.

METHOD

Data were collected from a demographically and diagnostically diverse mixed clinical sample of 100 veterans undergoing outpatient neuropsychological evaluation at a Southwestern VA Medical Center. As part of a larger battery of neuropsychological tests, all veterans completed TMT A and B and four independent criterion PVTs, which were used to classify veterans into valid (n = 75) and invalid (n = 25) groups. Among the valid group 47% (n = 35) were cognitively impaired.

RESULTS

Among the overall sample, all embedded PVTs derived from TMT A and B raw and demographically corrected T-scores significantly differed between validity groups (ηp2 = .21-.31) with significant areas under the curve (AUCs) of .72-.78 and 32-48% sensitivity (≥91% specificity) at optimal cut-scores. When subdivided by cognitive impairment status (i.e., valid-unimpaired vs. invalid; valid-impaired vs. invalid), all TMT scores yielded significant AUCs of .80-.88 and 56%-72% sensitivity (≥90% specificity) at optimal cut-scores. Among veterans with cognitive impairment, neither TMT A or B raw scores were able to significantly differentiate the invalid from the valid-cognitively impaired group; however, demographically corrected T-scores were able to significantly differentiate groups but had poor classification accuracy (AUCs = .66-.68) and reduced sensitivity of 28%-44% (≥91% specificity).

CONCLUSIONS

Embedded PVTs derived from TMT Parts A and B raw and T-scores were able to accurately differentiate valid from invalid neuropsychological performance among veterans without cognitive impairment; however, the demographically corrected T-scores generally were more robust and consistent with prior studies compared to raw scores. By contrast, TMT embedded PVTs had poor accuracy and low sensitivity among veterans with cognitive impairment, suggesting limited utility as PVTs among populations with cognitive dysfunction.

The association between symptom burden and processing speed and executive functioning at 4 and 12 weeks following pediatric concussion

OBJECTIVES

Symptoms and cognition are both utilized as indicators of recovery following pediatric concussion, yet their interrelationship is not well understood. This study aimed to investigate: 1) the association of post-concussion symptom burden and cognitive outcomes (processing speed and executive functioning [EF]) at 4 and 12 weeks after pediatric concussion, and 2) the moderating effect of sex on this association.

METHODS

This prospective, multicenter cohort study included participants aged 5.00-17.99 years with acute concussion presenting to four Emergency Departments of the Pediatric Emergency Research Canada network. Five processing speed and EF tasks and the Post-Concussion Symptom Inventory (PCSI; symptom burden, defined as the difference between post-injury and retrospective [pre-injury] scores) were administered at 4 and 12 weeks post-concussion. Generalized least squares models were conducted with task performances as dependent variables and PCSI and PCSI*sex interaction as the main predictors, with important pre-injury demographic and injury characteristics as covariates.

RESULTS

311 children (65.0% males; median age = 11.92 [IQR = 9.14-14.21 years]) were included in the analysis. After adjusting for covariates, higher symptom burden was associated with lower Backward Digit Span (χ2 = 9.85, p = .043) and Verbal Fluency scores (χ2 = 10.48, p = .033) across time points; these associations were not moderated by sex, ps ≥ .20. Symptom burden was not associated with performance on the Coding, Continuous Performance Test, and Color-Word Interference scores, ps ≥ .17.

CONCLUSIONS

Higher symptom burden is associated with lower working memory and cognitive flexibility following pediatric concussion, yet these associations were not moderated by sex. Findings may inform concussion management by emphasizing the importance of multifaceted assessments of EF.

A comprehensive characterization of cognitive performance, clinical symptoms, and cortical activity following mild traumatic brain injury (mTBI)

OBJECTIVE

The objective of this study was to investigate clinical symptoms, cognitive performance and cortical activity following mild traumatic brain injury (mTBI).

METHODS

We recruited 30 individuals in the sub-acute phase post mTBI and 28 healthy controls with no history of head injury and compared these groups on clinical, cognitive and cortical activity measures. Measures of cortical activity included; resting state electroencephalography (EEG), task related EEG and combined transcranial magnetic stimulation with electroencephalography (TMS-EEG). Primary analyses investigated clinical, cognitive and cortical activity differences between groups. Exploratory analyses investigated the relationships between these measures.

RESULTS

At 4 weeks' post injury, mTBI participants exhibited significantly greater post concussive and clinical symptoms compared to controls; as well as reduced cognitive performance on verbal learning and working memory measures. mTBI participants demonstrated alterations in cortical activity while at rest and in response to stimulation with TMS.

CONCLUSIONS

The present study comprehensively characterized the multidimensional effect of mTBI in the sub-acute phase post injury, showing a broad range of differences compared to non-mTBI participants. Further research is needed to explore the relationship between these pathophysiologies and clinical/cognitive symptoms in mTBI.

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.

Recovery of clinical, cognitive and cortical activity measures following mild traumatic brain injury (mTBI): A longitudinal investigation

The mechanisms that underpin recovery following mild traumatic brain injury (mTBI) remain poorly understood. Identifying neurophysiological markers and their functional significance is necessary to develop diagnostic and prognostic indicators of recovery. The current study assessed 30 participants in the subacute phase of mTBI (10-31 days post-injury) and 28 demographically matched controls. Participants also completed 3 month (mTBI: N = 21, control: N = 25) and 6 month (mTBI: N = 15, control: N = 25) follow up sessions to track recovery. At each time point, a battery of clinical, cognitive, and neurophysiological assessments was completed. Neurophysiological measures included resting-state electroencephalography (EEG) and transcranial magnetic stimulation combined with EEG (TMS-EEG). Outcome measures were analysed using mixed linear models (MLM). Group differences in mood, post-concussion symptoms and resting-state EEG resolved by 3 months, and recovery was maintained at 6 months. On TMS-EEG derived neurophysiological measures of cortical reactivity, group differences ameliorated at 3 months but re-emerged at 6 months, while on measures of fatigue, group differences persisted across all time points. Persistent neurophysiological changes and greater fatigue in the absence of measurable cognitive impairment may suggest the impact of mTBI on neuronal communication may leads to increased neural effort to maintain efficient function. Neurophysiological measures to track recovery may help identify both temporally optimal windows and therapeutic targets for the development of new treatments in mTBI.

Neuropsychological Function in Traumatic Brain Injury and the Influence of Chronic Pain

Cognitive dysfunction, pain, and psychological morbidity all present unique challenges to those living with traumatic brain injury (TBI). In this study we examined (a) the impact of pain across domains of attention, memory, and executive function, and (b) the relationships between pain and depression, anxiety, and post-traumatic stress disorder (PTSD) in persons with chronic TBI. Our sample included 86 participants with a TBI and chronic pain (n = 26), patients with TBI and no chronic pain (n = 23), and a pain-free control group without TBI (n = 37). Participants visited the laboratory and completed a comprehensive battery of neuropsychological tests as part of a structured interview. Multivariate analysis of covariance using education as a covariate, failed to detect a significant group difference for neuropsychological composite scores of attention, memory, and executive function (p = .165). A follow-up analysis using multiple one-way analysis of variance (ANOVA) was conducted for individual measures of executive function. Post-hoc testing indicated that those in both TBI groups preformed significantly worse on measures of semantic fluency when compared to controls (p < 0.001, ηρ2 = .16). Additionally, multiple ANOVAs indicated that those with TBI and pain scored significantly worse across all psychological assessments (p < .001). We also found significant associations between measures of pain and most psychological symptoms. A follow-up stepwise linear regression among those in the TBI pain group indicated that post concussive complaints, pain severity, and neuropathic pain symptoms differentially contributed to symptoms of depression, anxiety, and PTSD. These findings suggest deficits in verbal fluency among those living with chronic TBI, with results also reinforcing the multidimensional nature of pain and its psychological significance in this population.

Neuro-psychiatric symptoms in directly and indirectly blast exposed civilian survivors of urban missile attacks

BACKGROUND

Blast-explosion may cause traumatic brain injury (TBI), leading to post-concussion syndrome (PCS). In studies on military personnel, PCS symptoms are highly similar to those occurring in post-traumatic stress disorder (PTSD), questioning the overlap between these syndromes. In the current study we assessed PCS and PTSD in civilians following exposure to rocket attacks. We hypothesized that PCS symptomatology and brain connectivity will be associated with the objective physical exposure, while PTSD symptomatology will be associated with the subjective mental experience.

METHODS

Two hundred eighty nine residents of explosion sites have participated in the current study. Participants completed self-report of PCS and PTSD. The association between objective and subjective factors of blast and clinical outcomes was assessed using multivariate analysis. White-matter (WM) alterations and cognitive abilities were assessed in a sub-group of participants (n = 46) and non-exposed controls (n = 16). Non-parametric analysis was used to compare connectivity and cognition between the groups.

RESULTS

Blast-exposed individuals reported higher PTSD and PCS symptomatology. Among exposed individuals, those who were directly exposed to blast, reported higher levels of subjective feeling of danger and presented WM hypoconnectivity. Cognitive abilities did not differ between groups. Several risk factors for the development of PCS and PTSD were identified.

CONCLUSIONS

Civilians exposed to blast present higher PCS/PTSD symptomatology as well as WM hypoconnectivity. Although symptoms are sub-clinical, they might lead to the future development of a full-blown syndrome and should be considered carefully. The similarities between PCS and PTSD suggest that despite the different etiology, namely, the physical trauma in PCS and the emotional trauma in PTSD, these are not distinct syndromes, but rather represent a combined biopsychological disorder with a wide spectrum of behavioral, emotional, cognitive and neurological symptoms.

Potential Biomarkers in Experimental Animal Models for Traumatic Brain Injury

Traumatic brain injury (TBI) is a complex and multifaceted disorder that has become a significant public health concern worldwide due to its contribution to mortality and morbidity. This condition encompasses a spectrum of injuries, including axonal damage, contusions, edema, and hemorrhage. Unfortunately, specific effective therapeutic interventions to improve patient outcomes following TBI are currently lacking. Various experimental animal models have been developed to mimic TBI and evaluate potential therapeutic agents to address this issue. These models are designed to recapitulate different biomarkers and mechanisms involved in TBI. However, due to the heterogeneous nature of clinical TBI, no single experimental animal model can effectively mimic all aspects of human TBI. Accurate emulation of clinical TBI mechanisms is also tricky due to ethical considerations. Therefore, the continued study of TBI mechanisms and biomarkers, of the duration and severity of brain injury, treatment strategies, and animal model optimization is necessary. This review focuses on the pathophysiology of TBI, available experimental TBI animal models, and the range of biomarkers and detection methods for TBI. Overall, this review highlights the need for further research to improve patient outcomes and reduce the global burden of TBI.

Multivariate models provide an effective psychometric solution to the variability in classification accuracy of D-KEFS Stroop performance validity cutoffs

ObjectiveThe study was designed to expand on the results of previous investigations on the D-KEFS Stroop as a performance validity test (PVT), which produced diverging conclusions. Method The classification accuracy of previously proposed validity cutoffs on the D-KEFS Stroop was computed against four different criterion PVTs in two independent samples: patients with uncomplicated mild TBI (n = 68) and disability benefit applicants (n = 49). Results Age-corrected scaled scores (ACSSs) ≤6 on individual subtests often fell short of specificity standards. Making the cutoffs more conservative improved specificity, but at a significant cost to sensitivity. In contrast, multivariate models (≥3 failures at ACSS ≤6 or ≥2 failures at ACSS ≤5 on the four subtests) produced good combinations of sensitivity (.39-.79) and specificity (.85-1.00), correctly classifying 74.6-90.6% of the sample. A novel validity scale, the D-KEFS Stroop Index correctly classified between 78.7% and 93.3% of the sample. Conclusions A multivariate approach to performance validity assessment provides a methodological safeguard against sample- and instrument-specific fluctuations in classification accuracy, strikes a reasonable balance between sensitivity and specificity, and mitigates the invalid before impaired paradox.

Investigation of neurobiological responses to theta burst stimulation during recovery from mild traumatic brain injury (mTBI)

OBJECTIVE

The ability of the brain to recover following neurological insult is of interest for mild traumatic brain injury (mTBI) populations. Investigating whether non-invasive brain stimulation (NIBS) can modulate neurophysiology and cognition may lead to the development of therapeutic interventions post injury. The purpose of this study was to investigate neurobiological effects of one session of intermittent theta burst stimulation (iTBS) to the dorsolateral prefrontal cortex (DLPFC) in participants recovering from mTBI.

METHOD

Changes to neurophysiology were assessed with electroencephalography (EEG) and transcranial magnetic stimulation combined with EEG (TMS-EEG). Digit span working memory accuracy assessed cognitive performance. 30 patients were assessed within one-month of sustaining a mTBI and 26 demographically matched controls were assessed. Participants were also assessed at 3-months (mTBI: N = 21, control: N = 26) and 6-months (mTBI: N = 15, control: N = 24).

RESULTS

Analyses demonstrated iTBS did not reliably modulate neurophysiological activity, and no differences in cognitive performance were produced by iTBS at any assessment time-point.

CONCLUSIONS

Factors responsible for our null results are unclear. Possible limitations to our experimental design are discussed.

SIGNIFICANCE

Our findings suggest additional research is required to establish the effects of iTBS on plasticity following mTBI, prior to therapeutic application.

DATA AND CODE AVAILABILITY STATEMENT

We do not have ethical approval to make this data publicly available, as our approval predated our inclusion of such approvals (which we now do routinely).

Headaches in Traumatic Brain Injury: Improvement Over Time, Associations With Quality of Life, and Impact of Migraine-Type Headaches

OBJECTIVE

To describe headache characteristics over time in patients with traumatic brain injury (TBI).

SETTING

Patients enrolled and followed at the National Institutes of Health Clinical Center between 2011 and 2020.

PARTICIPANTS

There were 147 patients with TBI, with 74 mild TBI (mTBI), 49 moderate (modTBI), 24 severe (sTBI), and 20 individuals without brain injury (IWBIs).

DESIGN

Regular surveys of headache characteristics in patients with TBI were conducted. Patients were enrolled as early as 30 days post-injury and followed up to 5 years, for 419 total visits and 80 patients with multiple return visits.

MAIN MEASURES

Surveys of headache characteristics, including headache severity, were measured on a 0- to 10-point Likert scale and headache frequency quantified as headaches per month. Patients with migraine-type headaches ( n = 39) were identified by a clinician-administered tool. Functional outcomes were measured using the Glasgow Outcome Scale-Extended (GOS-E) and quality of life by the Satisfaction with Life Scale (SWLS) and the 36-item Short Form Survey (SF-36).

RESULTS

At their initial visit, patients with TBI had more severe and frequent headaches than IWBIs (median 5 vs 2.5, P < .001; median 2 vs 0.2, P < .001), as did patients with mTBI compared with modTBI/sTBI (all P ≤ .01). Migraines were associated with lower SWLS and SF-36 scores. Migraines and young age were associated with higher headache severity and frequency across time points. Longitudinally, time post-injury correlated with improvement in headache severity and frequency without differences by injury severity. However, time post-injury did not correlate with improvement in headache characteristics in a patient subgroup with moderate/severe headaches.

CONCLUSION

Our findings suggest that patients with mild, moderate, or severe TBI see improvement in headaches over time. However, patients should be counseled that improvement is modest and seen more in patients with milder headache symptoms. Patients with migraine headaches in particular are at risk for worse headache characteristics with greater impact on quality of life.

Return to work following mild traumatic brain injury: Psychological and cognitive factors in a litigating sample in the post acute stage of recovery

The purpose of this study was to investigate return to work (RTW) rates following a single uncomplicated mild Traumatic Brain Injury (mTBI) in the post-acute stage in the context of active litigation. More specifically, we sought to determine what psychological and/or cognitive factors predict a RTW after mTBI. Archival data were obtained from a random sample of litigating patients (n = 125; 54% female; mean age: 42.96 (SD = 12.74) who were referred to a private practice for a neuropsychological examination regarding their disability status following a single uncomplicated mTBI. A hierarchical regression analysis was used to assess the predictive value of emotional symptoms and cognition with respect to RTW status. Approximately 50% of the sample did not RTW. Attentional deficits (rs = -0.248) and depressive symptoms (rs = 0.248) were significantly associated with RTW. A hierarchical regression analysis found that depressive symptoms (p < .05) were associated with RTW outcomes. These findings suggest that individuals with increased depressive symptoms are more likely to demonstrate poor RTW outcomes in the post-acute stages of mTBI. These results are of interest to clinicians as they underscore the importance of screening and early intervention for depressive symptoms following a single uncomplicated mTBI in the post-acute stages in litigating samples.

Close proximity to blast: No long-term or lasting effect on cognitive performance in service members with and without TBI during blast exposure

OBJECTIVE

Blast related characteristics may contribute to the diversity of findings on whether mild traumatic brain injury sustained during war zone deployment has lasting cognitive effects. This study aims to evaluate whether a history of blast exposure at close proximity, defined as exposure within 30 feet, has long-term or lasting influences on cognitive outcomes among current and former military personnel.

METHOD

One hundred participants were assigned to one of three groups based on a self-report history of blast exposure during combat deployments: 47 close blast, 14 non-close blast, and 39 comparison participants without blast exposure. Working memory, processing speed, verbal learning/memory, and cognitive flexibility were evaluated using standard neuropsychological tests. In addition, assessment of combat exposure and current post-concussive, posttraumatic stress, and depressive symptoms, and headache was performed via self-report measures. Variables that differed between groups were controlled as covariates.

RESULTS

No group differences survived Bonferroni correction for family-wise error rate; the close blast group did not differ from non-close blast and comparison groups on measures of working memory, processing speed, verbal learning/memory, or cognitive flexibility. Controlling for covariates did not alter these results.

CONCLUSION

No evidence emerged to suggest that a history of close blast exposure was associated with decreased cognitive performance when comparisons were made with the other groups. Limited characterization of blast contexts experienced, self-report of blast distance, and heterogeneity of injury severity within the groups are the main limitations of this study.

Assessment of differential neurocognitive performance based on the number of performance validity tests failures: A cross-validation study across multiple mixed clinical samples

Objective: This cross-sectional study examined the effect of number of Performance Validity Test (PVT) failures on neuropsychological test performance among a demographically diverse Veteran (VA) sample (n = 76) and academic medical sample (AMC; n = 128). A secondary goal was to investigate the psychometric implications of including versus excluding those with one PVT failure when cross-validating a series of embedded PVTs. Method: All patients completed the same six criterion PVTs, with the AMC sample completing three additional embedded PVTs. Neurocognitive test performance differences were examined based on number of PVT failures (0, 1, 2+) for both samples, and effect of number of criterion failures on embedded PVT performance was analyzed among the AMC sample. Results: Both groups with 0 or 1 PVT failures performed better than those with ≥2 PVT failures across most cognitive tests. There were nonsignificant differences between those with 0 or 1 PVT failures except for one test in the AMC sample. Receiver operator characteristic curve analyses found no differences in optimal cut score based on number of PVT failures when retaining/excluding one PVT failure. Conclusion: Findings support the use of ≥2 PVT failures as indicative of performance invalidity. These findings strongly support including those with one PVT failure with those with zero PVT failures in diagnostic accuracy studies, given that their inclusion reflects actual clinical practice, does not reduce sample sizes, and does not artificially deflate neurocognitive test results or inflate PVT classification accuracy statistics.

The Key Role of Magnetic Resonance Imaging in the Detection of Neurodegenerative Diseases-Associated Biomarkers: A Review

Neurodegenerative diseases (NDs), including chronic disease such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis, and acute diseases like traumatic brain injury and ischemic stroke are characterized by progressive degeneration, brain tissue damage and loss of neurons, accompanied by behavioral and cognitive dysfunctions. So far, there are no complete cures for NDs; thus, early and timely diagnoses are essential and beneficial to patients' treatment. Magnetic resonance imaging (MRI) has become one of the advanced medical imaging techniques widely used in the clinical examination of NDs due to its non-invasive diagnostic value. In this review, research published in English in current decade from PubMed electronic database on the use of MRI to detect specific biomarkers of NDs was collected, summarized, and discussed, which provides valuable suggestions for the early diagnosis, prevention, and treatment of NDs in the clinic.

Neuropsychological Profile of Traumatic Brain Injury Patients with Medicolegal Cases: A Pilot Study

Introduction Traumatic brain injury (TBI) is a global health problem and is a silent epidemic of the modern times. Studies indicate litigation is a prominent factor that accounts for poor outcome and prolonged recovery from mild TBI. Depression is the most frequently diagnosed psychiatric disorder after TBI. Postconcussion symptoms, litigation, and suboptimal effort could contribute to the neuropsychological functioning of TBI patients medicolegal cases (MLCs). With increase in TBI and medicolegal cases, there is a requirement for comprehensive neuropsychological assessment.

Method The aim of the study was to evaluate the cognitive functions, postconcussion, and depressive symptoms in TBI patients with MLC and without MLCs (non-MLC). Patients were also assessed on electrophysiological parameters. An observational cross-sectional design was adopted, the sample size was 30 TBI patients in total, 15 (MLC) and 15 (non-MLC), and 11 patients from each group for electrophysiological assessment. The patients were in the age range of 18 to 50 years.

Results The MLC group had poor performance compared with the non-MLC group on both neuropsychological and electrophysiological measures. There was evidence of significant difference in verbal working memory, verbal learning, and memory and visuoconstructive ability. In the MLC group, postconcussion and depressive scores were negatively correlated with visuospatial span.

Conclusion Findings from this study indicate differences in the neuropsychological performance and electroencephalographic measures in between MLC and non-MLC groups. The results could be indicative of persistent cognitive problems associated with TBI for patients pursuing litigation. Poor performance could also be attributed to suboptimal level of effort. However, being a preliminary study with a small sample size, the findings need to be treated with caution.

Criterion validity of the brief test of adult cognition by telephone (BTACT) for mild traumatic brain injury

OBJECTIVES

There is a growing demand for remote assessment options for measuring cognition after mild traumatic brain injury (mTBI). The current study evaluated the criterion validity of the Brief Test of Adult Cognition by Telephone (BTACT) in distinguishing between adults with mTBI and trauma controls (TC) who sustained injuries not involving the head or neck.

METHODS

The BTACT was administered to the mTBI (n = 46) and TC (n = 35) groups at 1-2 weeks post-injury. Participants also completed the Rivermead Post Concussion Symptoms Questionnaire.

RESULTS

The BTACT global composite score did not significantly differ between the groups (t(79) = -1.04, p = 0.30); the effect size was small (d = 0.23). In receiver operating characteristic curve analyses, the BTACT demonstrated poor accuracy in differentiating between the groups (AUC = 0.567, SE = 0.065, 95% CI [0.44, 0.69]). The BTACT's ability to discriminate between mTBI and TCs did not improve after excluding mTBI participants (n = 15) who denied ongoing cognitive symptoms (AUC = 0.567, SE = 0.072, 95% CI [0.43, 0.71]).

CONCLUSIONS

The BTACT may lack sensitivity to subacute cognitive impairment attributable to mTBI (i.e., not explained by bodily pain, post-traumatic stress, and other nonspecific effects of injury).

Systematic Review and Meta-analysis of Outcome after Mild Traumatic Brain Injury in Older People

OBJECTIVE

Older age is often identified as a risk factor for poor outcome from traumatic brain injury (TBI). However, this relates predominantly to mortality following moderate-severe TBI. It remains unclear whether increasing age exerts risk on the expected recovery from mild TBI (mTBI). In this systematic review of mTBI in older age (60+ years), a focus was to identify outcome through several domains - cognition, psychological health, and life participation.

METHODS

Fourteen studies were identified for review, using PRISMA guidelines. Narrative synthesis is provided for all outcomes, from acute to long-term time points, and a meta-analysis was conducted for data investigating life participation.

RESULTS

By 3-month follow-up, preliminary findings indicate that older adults continue to experience selective cognitive difficulties, but given the data it is possible these difficulties are due to generalised trauma or preexisting cognitive impairment. In contrast, there is stronger evidence across time points that older adults do not experience elevated levels of psychological distress following injury and endorse fewer psychological symptoms than younger adults. Meta-analysis, based on the Glasgow Outcome Scale at 6 months+ post-injury, indicates that a large proportion (67%; 95% CI 0.569, 0.761) of older adults can achieve good functional recovery, similar to younger adults. Nevertheless, individual studies using alternative life participation measures suggest more mixed rates of recovery.

CONCLUSIONS

Although our initial review suggests some optimism in recovery from mTBI in older age, there is an urgent need for more investigations in this under-researched but growing demographic. This is critical for ensuring adequate health service provision, if needed.

Blast-related traumatic brain injury: Report of a severe case and review of the literature

Background:

Traumatic brain injury (TBI) is a well-known brain dysfunction commonly encountered in activities such as military combat or collision sports. The etiopathology can vary depending on the context and bomb explosions are becoming increasingly common in war zones, urban terrorist attacks, and civilian criminal feuds. Blast-related TBI may cause the full severity range of neurotrauma, from a mild concussion to severe, penetrating injury. Recent classifications of the pathophysiological mechanisms comprise five factors that reflect the gravity of the experienced trauma and suggest to the clinician different pathways of injury and consequent pathology caused by the explosion.

Case Description:

In the present report, the authors describe a case of 26 years old presenting with blast-related severe TBI caused by the detonation of an explosive in an amusement arcade. Surgical decompression to control intracranial pressure and systemic antibiotic treatment to manage and prevent wound infections were the main options available in a civilian hospital.

Conclusion:

While numerous studies examined the burden of blast-related brain injuries on service members, few papers have tackled this problem in a civilian setting, where hospitals are not sufficiently equipped, and physicians lack the necessary training. The present case demonstrates the urgent need for evidence-based diagnostic and therapeutic protocols in civilian hospitals that would improve the outcome of such patients.

Single-Nucleus RNA Sequencing Reveals that Decorin Expression in the Amygdala Regulates Perineuronal Nets Expression and Fear Conditioning Response after Traumatic Brain Injury

Traumatic brain injury (TBI) is a risk factor for posttraumatic stress disorder (PTSD). Augmented fear is a defining characteristic of PTSD, and the amygdala is considered the main brain region to process fear. The mechanism by which the amygdala is involved in fear conditioning after TBI is still unclear. Using single-nucleus RNA sequencing (snRNA-seq), transcriptional changes in cells in the amygdala after TBI are investigated. In total, 72 328 nuclei are obtained from the sham and TBI groups. 7 cell types, and analysis of differentially expressed genes (DEGs) reveals widespread transcriptional changes in each cell type after TBI are identified. In in vivo experiments, it is demonstrated that Decorin (Dcn) expression in the excitatory neurons of the amygdala significantly increased after TBI, and Dcn knockout in the amygdala mitigates TBI-associated fear conditioning. Of note, this effect is caused by a Dcn-mediated decrease in the expression of perineuronal nets (PNNs), which affect the glutamate-γ-aminobutyric acid balance in the amygdala. Finally, the results suggest that Dcn functions by interacting with collagen VI α3 (Col6a3). Consequently, the findings reveal transcriptional changes in different cell types of the amygdala after TBI and provide direct evidence that Dcn relieves fear conditioning by regulating PNNs.

Human platelet lysate biotherapy for traumatic brain injury: preclinical assessment

Traumatic brain injury (TBI) leads to major brain anatomopathological damages underlined by neuroinflammation, oxidative stress and progressive neurodegeneration, ultimately leading to motor and cognitive deterioration. The multiple pathological events resulting from TBI can be addressed not by a single therapeutic approach, but rather by a synergistic biotherapy capable of activating a complementary set of signalling pathways and providing synergistic neuroprotective, anti-inflammatory, antioxidative, and neurorestorative activities. Human platelet lysate might fulfil these requirements as it is composed of a plethora of biomolecules readily accessible as a TBI biotherapy. In the present study, we tested the therapeutic potential of human platelet lysate using in vitro and in vivo models of TBI. We first prepared and characterized platelet lysate from clinical-grade human platelet concentrates. Platelets were pelletized, lysed by three freeze-thaw cycles, and centrifuged. The supernatant was purified by 56°C 30 min heat treatment and spun to obtain the heat-treated platelet pellet lysate that was characterized by ELISA and proteomic analyses. Two mouse models were used to investigate platelet lysate neuroprotective potential. The injury was induced by an in-house manual controlled scratching of the animals' cortex or by controlled cortical impact injury. The platelet lysate treatment was performed by topical application of 60 µl in the lesioned area, followed by daily 60 µl intranasal administration from Day 1 to 6 post-injury. Platelet lysate proteomics identified over 1000 proteins including growth factors, neurotrophins, and antioxidants. ELISA detected several neurotrophic and angiogenic factors at ∼1-50 ng/ml levels. We demonstrate, using two mouse models of TBI, that topical application and intranasal platelet lysate consistently improved mouse motor function in the beam and rotarod tests, mitigated cortical neuroinflammation, and oxidative stress in the injury area, as revealed by downregulation of pro-inflammatory genes and the reduction in reactive oxygen species levels. Moreover, platelet lysate treatment reduced the loss of cortical synaptic proteins. Unbiased proteomic analyses revealed that heat-treated platelet pellet lysate reversed several pathways promoted by both controlled cortical impact and cortical brain scratch and related to transport, postsynaptic density, mitochondria or lipid metabolism. The present data strongly support, for the first time, that human platelet lysate is a reliable and effective therapeutic source of neurorestorative factors. Therefore, brain administration of platelet lysate is a therapeutical strategy that deserves serious and urgent consideration for universal brain trauma treatment.

King-Devick Test Performance and Cognitive Dysfunction after Concussion: A Pilot Eye Movement Study

(1) Background: The King-Devick (KD) rapid number naming test is sensitive for concussion diagnosis, with increased test time from baseline as the outcome measure. Eye tracking during KD performance in concussed individuals shows an association between inter-saccadic interval (ISI) (the time between saccades) prolongation and prolonged testing time. This pilot study retrospectively assesses the relation between ISI prolongation during KD testing and cognitive performance in persistently-symptomatic individuals post-concussion. (2) Results: Fourteen participants (median age 34 years; 6 women) with prior neuropsychological assessment and KD testing with eye tracking were included. KD test times (72.6 ± 20.7 s) and median ISI (379.1 ± 199.1 msec) were prolonged compared to published normative values. Greater ISI prolongation was associated with lower scores for processing speed (WAIS-IV Coding, r = 0.72, p = 0.0017), attention/working memory (Trails Making A, r = −0.65, p = 0.006) (Digit Span Forward, r = 0.57, p = −0.017) (Digit Span Backward, r= −0.55, p = 0.021) (Digit Span Total, r = −0.74, p = 0.001), and executive function (Stroop Color Word Interference, r = −0.8, p = 0.0003). (3) Conclusions: This pilot study provides preliminary evidence suggesting that cognitive dysfunction may be associated with prolonged ISI and KD test times in concussion.

"I Couldn't Be Better": Assessing Self-Awareness With the Mayo-Portland Adaptability Inventory-4 Following TBI

INTRODUCTION/OBJECTIVE

To describe level of awareness, as assessed by the Mayo-Portland Adaptability Inventory-4 (MPAI-4), across physical, cognitive, functional, and emotional domains in individuals with mild, moderate, and severe traumatic brain injury (TBI) participating in a residential rehabilitation program. In addition, this study aimed to examine the relationship between time since injury and awareness. A novel way the MPAI-4 can be used to measure self-awareness is also presented.

METHOD

Retrospective analysis of existing data. The MPAI-4 was completed by the patient on admission, as well as by provider consensus within 2 weeks of admission. Level of awareness was determined by discrepancy scores, computed as MPAI-4 provider consensus score minus self-report MPAI-4 score, for the total score and for each index score: Ability, Adjustment, and Participation.

PARTICIPANTS

A total of 101 military veterans and active duty service members admitted to a Veterans Affairs community reintegration rehabilitation program.

RESULTS

Discrepancies between patient and provider reports of functioning were found among all severities of TBI across the MPAI-4 total score and index domains measuring Ability, Adjustment, and Participation. Interestingly, those with mild TBI endorsed greater impairments than their providers, while those with moderate and severe TBI reported less impairment on the MPAI-4 than providers. The effect of time varied across domains, and those who were more than 1 year postinjury displayed greater self-awareness.

CONCLUSION

This study highlights the importance of measuring awareness of functional ability over time and across TBI severity and introduces a novel method for doing so, using the MPAI-4 for comparison between staff and patient reports.

Long-term effects of concussion on relevancy-based modulation of somatosensory-evoked potentials

OBJECTIVE

The purpose of this investigation was to better understand the effects of concussions on the ability to selectively up or down-regulate incoming somatosensory information based on relevance.

METHODS

Median nerve somatosensory-evoked potentials (SEPs) were elicited from electrical stimulation and recorded from scalp electrodes while participants completed tasks that altered the relevance of specific somatosensory information being conveyed along the stimulated nerve.

RESULTS

Within the control group, SEP amplitudes for task-relevant somatosensory information were significantly greater than for non-relevant somatosensory information at the earliest cortical processing potentials (N20-P27). Alternatively, the concussion history group showed similar SEP amplitudes for all conditions at early processing potentials, however a pattern similar to controls emerged later in the processing stream (P100) where both movement-related gating and facilitation of task-relevant information were present.

CONCLUSIONS

Previously concussed participants demonstrated impairments in the ability to up-regulate relevant somatosensory information at early processing stages. These effects appear to be chronic, as this pattern was observed on average several years after participants' most recent concussion.

SIGNIFICANCE

Given the role of the prefrontal cortex in relevancy-based facilitation during movement-related gating, these findings lend support to the notion that this brain area may be particularly vulnerable to concussive forces.

Interprofessional Collaborative Management of Postconcussion Cognitive Symptoms

Purpose The purpose of this clinical focus article is to illustrate an interprofessional cognitive rehabilitation approach. Invited experts representing physical medicine and rehabilitation, clinical neuropsychology/rehabilitation psychology, registered nurse care coordination, and speech-language pathology share viewpoints from their discipline to engage in collaborative interventions with the goal of enhancing treatment outcomes. Conclusions Treating the multifactorial symptoms of concussion requires expertise from an interdisciplinary team (IDT) of professionals, contributing unique perspectives and providing integrative services to optimize rehabilitation outcomes for patients. Speech-language pathologists serve an important role on IDTs to deliver personalized, targeted therapies for prolonged or persistent postconcussion cognitive impairment.

Examining Conners Continuous Performance Test-3 (CPT-3) Embedded Performance Validity Indicators in an Adult Clinical Sample Referred for ADHD Evaluation

This study evaluated multiple previously-identified Continuous Performance Test-Third Edition (CPT-3) scores as embedded validity indicators (EVIs) among 201 adults undergoing neuropsychological evaluation for Attention-Deficit/Hyperactivity Disorder (ADHD) divided into valid (n = 169) and invalid (n = 32) groups based on seven criterion measures. Although 6/10 CPT-3 scores accurately detected invalidity, only two reached minimally acceptable classification accuracy of ≥0.70. The remaining four had unacceptably low accuracy (AUCs = 0.62-0.69) with 0.19-0.41 sensitivity at ≥0.90 specificity. Composite scores did not provide better classification accuracy than individual CPT-3 scores. In sum, CPT-3 individual and composite scores generally are not accurate PVTs among adults undergoing clinical evaluation for ADHD.

Omega-3 Fatty Acids and Vitamin D Decrease Plasma T-Tau, GFAP, and UCH-L1 in Experimental Traumatic Brain Injury

Traumatic brain injury (TBI) results in neuronal, axonal and glial damage. Interventions targeting neuroinflammation to enhance recovery from TBI are needed. Exercise is known to improve cognitive function in TBI patients. Omega-3 fatty acids and vitamin D reportedly reduce inflammation, and in combination, might improve TBI outcomes. This study examined how an anti-inflammatory diet affected plasma TBI biomarkers, voluntary exercise and behaviors following exposure to mild TBI (mTBI). Adult, male rats were individually housed in cages fitted with running wheels and daily running distance was recorded throughout the study. A modified weight drop method induced mTBI, and during 30 days post-injury, rats were fed diets supplemented with omega-3 fatty acids and vitamin D₃ (AIDM diet), or non-supplemented AIN-76A diets (CON diet). Behavioral tests were periodically conducted to assess functional deficits. Plasma levels of Total tau (T-tau), glial fibrillary acidic protein (GFAP), ubiquitin c-terminal hydrolase L1 (UCH-L1) and neurofilament light chain (NF-L) were measured at 48 h, 14 days, and 30 days post-injury. Fatty acid composition of food, plasma, and brain tissues was determined. In rats exposed to mTBI, NF-L levels were significantly elevated at 48 h post-injury (P < 0.005), and decreased to levels seen in uninjured rats by 14 days post-injury. T-tau, GFAP, and UCH-L1 plasma levels did not change at 48 h or 14 days post-injury. However, at 30 days post-injury, T-tau, GFAP and UCH-L1 all significantly increased in rats exposed to mTBI and fed CON diets (P < 0.005), but not in rats fed AIDM diets. Behavioral tests conducted post-injury showed that exercise counteracted cognitive deficits associated with mTBI. The AIDM diets significantly increased docosahexaenoic acid levels in plasma and brain tissue (P < 0.05), and in serum levels of vitamin D (P < 0.05). The temporal response of the four injury biomarkers examined is consistent with studies by others demonstrating acute and chronic neural tissue damage following exposure to TBI. The anti-inflammatory diet significantly altered the temporal profiles of plasma T-tau, GFAP, and UCH-L1 following mTBI. Voluntary exercise protected against mTBI-induced cognitive deficits, but had no impact on plasma levels of neurotrauma biomarkers. Thus, the prophylactic effect of exercise, when combined with an anti-inflammatory diet, may facilitate recovery in patients with mTBI.

Physical Conditioning Strategies for the Prevention of Concussion in Sport: a Scoping Review

BACKGROUND

Concussion in sports has received a great deal of media attention and may result in short and longer-lasting symptoms, especially in adolescents. Although significant strides have been made in the identification and management of concussion, less is known about the primary prevention of this condition. The aims of this scoping review are to (1) summarize the current research of physical conditioning strategies to reduce or prevent concussion incidence in individuals participating in sport, especially adolescents, and (2) to identify gaps in the knowledge base. Our research question was what is known from the existing literature about physical preparation strategies to reduce or prevent concussion in adult and adolescent sports?

METHODS

Three literature searches were conducted by information officers at two universities at six-month intervals, using five electronic databases (PubMed; WorldCat.org ; Mendeley; EBSCOHost and Ovid MEDLINE). To increase the search range, subject experts were consulted and articles and reference lists were hand searched. A scoping review methodology identified eligible studies that analyzed physical preparation techniques on modifiable physical risk factors in athletes to reduce the incidence of concussion. The PRISMA-ScR checklist guided the reporting of the findings.

RESULTS

A total of 1414 possible articles were identified, after duplicates removed, and articles analyzed against the inclusion and exclusion criteria, only 9 articles qualified for analysis. Two articles were found from studying reference lists. Thus, a total of 11 articles were included in the final evaluation for the purposes of this study. Data are reported from mostly adolescent subjects participating in nine different sports from three countries. Findings are presented with specific reference to previously recognized modifiable risk factors of concussion which include neck strength, neck size, cervical stiffness, type of sport, and pre-activity exercises.

CONCLUSIONS

There is limited research examining the physical preparation of athletes, especially in adolescents, to reduce or prevent concussion, and conflicting evidence in the few small sample studies that were identified. This scoping review identifies the research gap for a potentially vital modifiable risk factor, notably in the physical preparation of children and adolescents to reduce or prevent sports-related concussion.

Differential effects of deployment and nondeployment mild TBI on neuropsychological outcomes

Objective: Mild traumatic brain injury (TBI) that occurs in a deployment environment is characteristically different from mild TBI that occurs outside of deployment. This study evaluated differential and interaction effects of deployment and nondeployment mild TBI on cognitive and behavioral health outcomes. Research Method: Combat veterans (N = 293) who passed performance-validity measures completed the Mid-Atlantic MIRECC Assessment of TBI (MMA-TBI), Clinician-Administered Posttraumatic Stress Disorder (PTSD) Scale (CAPS-5), a neuropsychological assessment battery, and self-report questionnaires. A 2 × 2 × 2 analysis of variance (ANOVA) was conducted to evaluate the main and interaction effects across mild TBI groups and PTSD diagnosis. Results: Deployment TBI was associated with poorer outcomes on several cognitive tests: Wechsler Adult Intelligence Scale, 4th edition (WAIS-IV); Working Memory Index (WMI; p = .018); Trail Making Test A (TMT-A; p < .001); and Trail Making Test B (TMT-B; p = .002). Deployment TBI and PTSD were also associated with increased PTSD, depressive, and neurobehavioral symptoms; pain interference; and poorer sleep quality. Nondeployment TBI had no effect on cognitive performance and was associated only with poorer sleep quality. PTSD had the strongest associations with symptom measures and deployment TBI with cognitive outcomes. There were no significant interaction effects after adjusting for multiple comparisons. Conclusions: Remote outcomes associated with mild deployment TBI are different from those associated with nondeployment mild TBI and are robust beyond PTSD. This suggests that the environment surrounding a TBI event influences cognitive and symptom sequelae. Veterans who experience mild TBI during deployment may report changes in cognition, but most will continue to function within the expected range. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

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.

Elevated Intraindividual Variability in Executive Functions and Associations with White Matter Microstructure in Veterans with Mild Traumatic Brain Injury

OBJECTIVE

We examined whether intraindividual variability (IIV) across tests of executive functions (EF-IIV) is elevated in Veterans with a history of mild traumatic brain injury (mTBI) relative to military controls (MCs) without a history of mTBI. We also explored relationships among EF-IIV, white matter microstructure, and posttraumatic stress disorder (PTSD) symptoms.

METHOD

A total of 77 Veterans (mTBI = 43, MCs = 34) completed neuropsychological testing, diffusion tensor imaging (DTI), and PTSD symptom ratings. EF-IIV was calculated as the standard deviation across six tests of EF, along with an EF-Mean composite. DSI Studio connectometry analysis identified white matter tracts significantly associated with EF-IIV according to generalized fractional anisotropy (GFA).

RESULTS

After adjusting for EF-Mean and PTSD symptoms, the mTBI group showed significantly higher EF-IIV than MCs. Groups did not differ on EF-Mean after adjusting for PTSD symptoms. Across groups, PTSD symptoms significantly negatively correlated with EF-Mean, but not with EF-IIV. EF-IIV significantly negatively correlated with GFA in multiple white matter pathways connecting frontal and more posterior regions.

CONCLUSIONS

Veterans with mTBI demonstrated significantly greater IIV across EF tests compared to MCs, even after adjusting for mean group differences on those measures as well as PTSD severity. Findings suggest that, in contrast to analyses that explore effects of mean performance across tests, discrepancy analyses may capture unique variance in neuropsychological performance and more sensitively capture cognitive disruption in Veterans with mTBI histories. Importantly, findings show that EF-IIV is negatively associated with the microstructure of white matter pathways interconnecting cortical regions that mediate executive function and attentional processes.

Apolipoprotein E (APOE) ε4 Status Moderates the Relationship Between Close-Range Blast Exposure and Cognitive Functioning

OBJECTIVES

Recent studies suggest that close-range blast exposure (CBE), regardless of acute concussive symptoms, may have negative long-term effects on brain health and cognition; however, these effects are highly variable across individuals. One potential genetic risk factor that may impact recovery and explain the heterogeneity of blast injury's long-term cognitive outcomes is the inheritance of an apolipoprotein (APOE) ε4 allele, a well-known genetic risk factor for Alzheimer's disease. We hypothesized that APOE ε4 carrier status would moderate the impact of CBE on long-term cognitive outcomes.

METHODS

To test this hypothesis, we examined 488 post-9/11 veterans who completed assessments of neuropsychological functioning, psychiatric diagnoses, history of blast exposure, military and non-military mild traumatic brain injuries (mTBIs), and available APOE genotypes. We separately examined the effects of CBE on attention, memory, and executive functioning in individuals with and without the APOE ε4 allele.

RESULTS

As predicted, we observed a differential impact of CBE status on cognition as a function of APOE ε4 status, in which CBE ε4 carriers displayed significantly worse neuropsychological performance, specifically in the domain of memory. These results persisted after adjusting for clinical, demographic, and genetic factors and were not observed when examining other neurotrauma variables (i.e., lifetime or military mTBI, distant blast exposure), though these variables displayed similar trends.

CONCLUSIONS

These results suggest APOE ε4 carriers are more vulnerable to the impact of CBE on cognition and highlight the importance of considering genetic risk when studying cognitive effects of neurotrauma.

Accelerated repetitive transcranial magnetic stimulation in the treatment of post-concussion symptoms due to mild traumatic brain injury: a pilot study

Objective: To investigate the feasibility, tolerability, and efficacy of twice-daily, low frequency (LF) repetitive transcranial magnetic stimulation (rTMS) over the right dorsolateral prefrontal cortex (DLPFC) in the reduction of chronic post-concussion symptoms (PCS) in patients who have suffered a mild traumatic brain injury (mTBI).Methods: 15 patients with mTBI received 30 sessions of twice-daily LF rTMS (1 Hz) over the right DLPFC. Post-concussion symptoms, pain, disability, fatigue, apathy, agitation, and mood were assessed by a psychiatrist pre- and post-treatment. Cognitive testing was also performed pre-, mid-, and post-rTMS.Results: All participants completed treatment with no serious adverse events. Significant improvements were observed in overall post-concussion symptoms, disability and pain ratings, as well as depression and anxiety symptoms. There was no significant change in overall executive functioning, fatigue severity, apathy, or agitation. Cognitive testing revealed improvements in verbal fluency, working memory, selective attention, and cognitive processing speed.Conclusions: This small-sample pilot study suggests that twice-daily, LF rTMS over the right DLPFC can be safely and tolerably applied and has the potential to improve post-concussion symptoms as well as elements of mood and cognition in patients with mTBI. Larger, sham-controlled studies will be important to confirm these observations.

Obstructive Sleep Apnea Risk Is Associated with Cognitive Impairment after Controlling for Mild Traumatic Brain Injury History: A Chronic Effects of Neurotrauma Consortium Study

The contribution of sleep disturbance to persistent cognitive symptoms following a mild traumatic brain injury (mTBI) remains unclear. Obstructive sleep apnea (OSA) is very common, yet its relationship between risk factors for developing OSA and cognitive performance in those with history of mTBI has not been investigated. The current study examined OSA risk levels and its association with cognitive performance in 391 combat-exposed, post-911 veterans and service members (median age = 37 years) enrolled in the Chronic Effects of Neurotrauma Consortium (CENC) prospective multi-center study. Participants included those with and without mTBI (n = 326 and 65, respectively). When using clinical cut-offs, those with history of mTBI were more likely to be categorized as high risk for OSA (mTBI positive = 65% vs. mTBI negative = 51%). After adjustment for TBI status and demographic variables, increased OSA risk was significantly associated with worse performance on measures of complex processing speed and executive functioning (Wechsler Adult Intelligence Scale Fourth Edition Coding, Trail Making Test, part B) and greater symptom burden (Neurobehavioral Symptom Inventory). Thus, OSA, a modifiable behavioral health factor, likely contributes to cognitive performance following mTBI. Accordingly, OSA serves as a potential point of intervention to improve clinical and cognitive outcomes after injury.

Characteristics and Impact of U.S. Military Blast-Related Mild Traumatic Brain Injury: A Systematic Review

As a result of armed conflict, head trauma from exposure to blasts is an increasing critical health issue, particularly among military service members. Whilst numerous studies examined the burden of blast-related brain injuries on service members', few systematic reviews have been published. This work provides a comprehensive summary of the evidence on blast-related mild traumatic brain injury (mTBI) burden in active U.S. military service members and inactive Veterans, describing characteristics and outcomes. Records published up to April 2017 were identified through a search of PubMed, Web of Science, Scopus, Ovid MEDLINE, and Cochrane Library. Records-based and original research reporting on U.S. military service members and Veterans with mild blast TBI were included. Data on subject characteristics, exposure, diagnostic criterion, and outcomes were extracted from included studies using a standardized extraction form and were presented narratively. Of the 2,290 references identified by the search, 106 studies with a total of 37,515 participants met inclusion criteria for blast-related mTBI. All but nine studies were based out of military or Veteran medical facilities. Unsurprisingly, men were over-represented (75–100%). The criteria used to define blast-related mTBI were consistent; however, the methodology used to ascertain whether individuals met those criteria for diagnosis were inconsistent. The diagnosis, most prevalent among the Army, heavily relied on self-reported histories. Commonly reported adverse outcomes included hearing disturbances and headaches. The most frequently associated comorbidities were post-traumatic stress disorder, depression, anxiety, sleep disorders, attention disorders, and cognitive disorders. The primary objective of this review was to provide a summary of descriptive data on blast-related mTBI in a U.S. military population. Low standardization of the methods for reaching diagnosis and problems in the study reporting emphasize the importance to collect high-quality data to fill knowledge gaps pertaining to blast-related mTBI.

AQP4-siRNA alleviates traumatic brain edema by altering post-traumatic AQP4 polarity reversal in TBI rats

The spatial and temporal distribution of aquaporin-4 (AQP4) expression in rat brain following brain trauma and AQP4-siRNA treatment, as well as corresponding pathological changes, were studied to explore the mechanism underlying the effect of AQP4-siRNA treatment on traumatic brain injury (TBI). The rats in the sham operation group had normal structure, with AQP4 located in the perivascular end-foot membranes and astrocytic membranes in a polarized pattern. The accelerated polarity reversal was observed in the TBI group in 1-12 h after TBI. During this period, AQP4 abundance on the astrocytic membrane is gradually increased, while AQP4 abundance on the perivascular end-foot membrane declined rapidly. Twelve hours after TBI, AQP4 expression was depolarized, showing a shift from the perivascular end-foot membrane to the astrocytic membrane. Pathological observation showed that vasogenic edema occurred immediately after TBI, at which time the extracellular space was expanded, leading to severe intracellular edema. AQP4-siRNA reduced the polarity reversal index at the early stage of TBI recovery and reduced edema, demonstrating the potential benefit of reduced AQP4 expression during recovery from TBI.

Post-traumatic cephalalgia

After traumatic brain injury (TBI), a host of symptoms of varying severity and associated functional impairment may occur. One of the most commonly encountered and challenging to treat are the post-traumatic cephalalgias. Post-traumatic cephalalgia (PTC) or headache is often conceptualized as a single entity as currently classified using the ICHD-3. Yet, the terminology applicable to the major primary, non-traumatic, headache disorders such as migraine, tension headache, and cervicogenic headache are often used to specify the specific type of headache the patients experiences seemingly disparate from the unitary definition of post-traumatic headache adopted by ICHD-3. More complex post-traumatic presentations attributable to brain injury as well as other headache conditions are important to consider as well as other causes such as medication overuse headache and medication induced headache. Treatment of any post-traumatic cephalalgia must be optimized by understanding that there may be more than one headache pain generator, that comorbid traumatic problems may contribute to the pain presentation and that pre-existing conditions could impact both symptom complaint, clinical presentation and recovery. Any treatment for PTC must harmonize with ongoing medical and psychosocial aspects of recovery.

[Formula: see text] The role of family burden on informant discrepancies between parents and youths with protracted recovery from mild traumatic brain injury

Previous literature shows that family burden can lead to symptom-report discrepancies between parents and children. The present study sought to extend this research by investigating the influence of family burden factors, including socioeconomic status (SES) and family stress on informant discrepancies between parents and youths with mild traumatic brain injury (mTBI). Participants were clinically referred youths with mTBI ages 8-17, consecutively seen in a hospital-based neuropsychology concussion clinic (N = 81; females = 54.3%). Parents and children completed the Behavioral Assessment for Children System (BASC) and the Postconcussive Symptom Scale (PCSS). Parents rated changes in family stress related to the mTBI (categorized as "no change," "minor change," or "major change") and provided information to calculate SES. Results revealed that family stress but not SES influenced parent-child report discrepancies for the BASC Internalizing Symptoms Index (F = 8.72(2, 79), p <.000), and that the discrepancies were independent of postconcussive symptom severity. Clinical implications of these findings are discussed.

Associations Between Multiple Remote Mild TBIs and Objective Neuropsychological Functioning and Subjective Symptoms in Combat-Exposed Veterans

OBJECTIVE

The purpose of this study was to evaluate relationships between multiple mild traumatic brain injuries (mTBIs) and objective and subjective clinical outcomes in a sample of combat-exposed Veterans, adjusting for psychiatric distress and combat exposure.

METHOD

In this cross-sectional study, 73 combat-exposed Iraq/Afghanistan Veterans were divided into three groups based on mTBI history: 0 mTBIs (n = 31), 1-2 mTBIs (n = 21), and 3+ mTBIs (n = 21). Veterans with mTBI were assessed, on average, 7.78 years following their most recent mTBI. Participants underwent neuropsychological testing and completed self-report measures assessing neurobehavioral, sleep, and pain symptoms.

RESULTS

MANCOVAs adjusting for psychiatric distress and combat exposure showed no group differences on objective measures of attention/working memory, executive functioning, memory, and processing speed (all p's > .05; ηp2 = .00-.06). In contrast, there were significant group differences on neurobehavioral symptoms (p's = < .001-.036; ηp2 = .09-.43), sleep difficulties (p = .037; ηp2 = .09), and pain symptoms (p < .001; ηp2 = .21). Pairwise comparisons generally showed that the 3+ mTBI group self-reported the most severe symptoms, followed by comparable symptom reporting between the 0 and 1-2 mTBI groups.

CONCLUSIONS

History of multiple, remote mTBIs is associated with elevated subjective symptoms but not objective neuropsychological functioning in combat-exposed Veterans. These results advance understanding of the long-term consequences of repetitive mTBI in this population and suggest that Veterans with 3+ mTBIs may especially benefit from tailored treatments aimed at ameliorating specific neurobehavioral, sleep, and pain symptoms.

Influence of blast exposure on cognitive functioning in combat veterans

OBJECTIVE

We evaluated the contribution of blast-pressure severity to cognitive functioning beyond posttraumatic stress disorder (PTSD) severity and traumatic brain injury (TBI).

METHOD

Post-9/11 veterans (N = 254, 86.22% male) completed the Wechsler Adult Intelligence Scale (WAIS-IV) and Trail Making Test (TMT). The Clinician-Administered PTSD Scale (CAPS-5), Mid-Atlantic MIRECC Assessment of TBI, and the Salisbury Blast Interview evaluated PTSD diagnosis/severity, deployment TBI history/severity, and blast-exposure history/severity, respectively.

RESULTS

Veterans with mild deployment TBI had overall significantly lower T scores on the WAIS-IV Verbal Comprehension Index (d = .13), Working Memory Index (d = .30), and Processing Speed Index (d = .25); the Trail Making Test A (TMT-A; d = .50); and the Trail Making Test B (TMT-B; d = .37). Mild deployment TBI was significantly associated with TMT-A (ΔR² = .05, p < .001) and TMT-B (ΔR² = .03, p = .001) performance. Blast-pressure severity moderated the association between mild deployment TBI and TMT-A (ΔR² = .02, p = .039, B = -2.01).

CONCLUSION

Blast-pressure severity exacerbated the effects of mild TBI on a simple attention task, such that participants with TBI had gradual decrements in attention as blast severity increased. Veterans who incur a TBI and are exposed to blasts during deployment may experience persisting difficulties with cognitive functioning as a result of alterations in basic attention abilities. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Soccer heading and subclinical neuropsychiatric symptomatology in professional soccer players

Objectives

To evaluate the association between postconcussive symptomatology and heading in professional soccer players, overcoming the bias of self-reported exposure, we evaluated several clinical neuropsychiatric symptoms using questionnaires after a thorough objective follow-up of players’ heading exposure throughout an entire season.

Methods

We collected heading data for all Israeli Premier League players for an entire season using a web-based platform for performance analysis, which enabled us to quantify the exact number of headers per player. Players filled out questionnaires regarding postconcussion symptoms, depression, anxiety, and sleep disorders. We tested the association between the number of headers and each outcome using a negative binomial regression corrected for the hours played.

Results

A total of 159 players were included, of whom 79 were considered in the high heading exposure group (49%), defined as more than median number of headings (1.34 per game hour). Among players without any past head injury, those with higher heading exposure were less likely to have postconcussion symptoms compared with players with low heading exposure (relative risk [RR] per heading per hour 0.94, 95% confidence interval [CI] 0.912–0.963). Players with high heading exposure had fewer depression symptoms (RR 0.98, 95% CI 0.961–0.997), anxiety (RR 0.98, 95% CI 0.958–0.997), and sleep disorders (RR 0.98, 95% CI 0.961–0.996).

Conclusion

Professional soccer players with high heading rate do not display higher postconcussive symptomatology severity. Symptoms among players with low heading exposure might be explained by low resilience, possibly associated with an inferior heading technique. Alternatively, it can reflect heading-avoidant behavior.