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Primary Objective: This is Part II of a four-part opinion review on traditional neuropsychological assessment methods and findings associated with mild traumatic brain injury (mTBI). This Part II review focuses on historical, psychometric and statistical issues involving traditional neuropsychological methods that have been used in neuropsychological outcome studies of mTBI, but demonstrates the critical limitations of traditional methods., Research Design: This is an opinion review., Methods and Procedures: Traditional neuropsychological tests are dated and lack specificity in evaluating such a heterogenous and complex injury as occurs with mTBI., Main Outcome and Results: In this review, we demonstrate traditional neuropsychological methods were never developed as standalone measures for detecting subtle changes in neurocognitive or neurobehavioral functioning and likewise, never designed to address the multifaceted issues related to underlying mTBI neuropathology symptom burden from having sustained a concussive brain injury., Conclusions: For neuropsychological assessment to continue to contribute to clinical practice and outcome literature involving mTBI, major innovative changes are needed that will likely require technological advances of novel assessment techniques more specifically directed to evaluating the mTBI patient. These will be discussed in Part IV.

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.

Background: To investigate the long-term outcome of pediatric mild traumatic brain injury (mTBI) in terms of neurocognitive, behavioral, and school functioning and to identify clinical risk factors for adverse outcomes., Methods: This study describes the follow-up of a prospective multicenter sample of 89 children with mTBI 3.6 years postinjury and 89 neurologically healthy children matched for sex, age, and socioeconomic status. Neurodevelopmental outcomes were assessed using an intelligence test, behavioral questionnaires, computerized neurocognitive tests, and longitudinal (pre- and postinjury) standardized school performance data., Results: Children with mTBI exhibited intelligence in the average range but had more behavioral problems related to inattentiveness (P = 0.004, d = 0.47) and hyperactive impulsivity (P = 0.01, d = 0.40) and showed poorer neurocognitive performance in information processing stability (P = 0.003, d = -0.55) and Visual Working Memory (P = 0.04, d = -0.39) compared with matched peers. Longitudinal school performance data revealed poorer performance in Technical Reading up to two years postinjury (P = 0.005, d = -0.42) when compared with normative data. Clinical risk factors did not reveal predictive value for adverse outcomes in children with mTBI., Conclusions: This study indicates that children with mTBI are at risk of long-term deficits in neurocognitive and behavioral functioning, with longitudinal evidence suggesting shortfalls in school performance up to two years postinjury. Clinical risk factors do not provide a solid basis for long-term neurodevelopmental prognosis. Findings emphasize the importance of, and challenges for, early identification of children at risk for adverse neurodevelopmental outcome after mTBI., Competing Interests: Declaration of competing interest Conflicts of interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Mild traumatic brain injury (mTBI) and posttraumatic stress are prevalent in military service members and share objective and subjective cognitive symptoms, complicating recovery. We investigated the effects of remote mTBI characteristics and current posttraumatic stress symptoms on neuropsychological performance in 152 veterans with a history of remote mTBI and current cognitive concerns. Participants completed clinical neuropsychological evaluations within a Veterans Affairs Level-II TBI/Polytrauma outpatient clinic (i.e. tertiary trauma care center for US military veterans outside of a research or teaching hospital setting). Archival data analysis of mTBI injury characteristics, clinical diagnoses, scores on the Posttraumatic Stress Disorder Checklist-Military Version (PCL-M) and performance on tests of processing speed, attention and executive function was conducted. Hierarchical linear regression demonstrated that elevated PCL-M scores were associated with slower performance on trail making test (TMT) Parts A and B (p < .016). PCL-M symptoms moderated the effect of alteration of consciousness (AOC) on TMT performance, with endorsement of AOC associated with better performance, but only when PCL-M scores were high (p < .005). Follow-up mediation analyses demonstrated that PCL-M score fully mediated the relationship between AOC and TMT-A performance and partially mediated the relationship between AOC and TMT-B performance. Post-hoc analyses meant to separate the impact of processing speed on TMT-B were all non-significant. Remote mTBI characteristics, specifically AOC, were not associated with decrements in cognitive performance. Posttraumatic symptoms were associated with worse processing speed, suggesting that psychological distress and psychopathology are contributing factors in understanding and treating persistent cognitive distress following remote mTBI., (© 2024 The British Psychological Society.)

Objective: To assess cognitive status in elderly patients with mild traumatic brain injury (mTBI) in the subacute phase, examine the role of cognitive reserve, and investigate associations with cognitive complaints, mental distress, and functional outcomes., Setting: A level 1 trauma center in the Netherlands., Participants: A total of 52 individuals with mTBI and 42 healthy controls., Design: A prospective observational cohort study., Main Measures: Neuropsychological assessment in the subacute phase (2 weeks to 6 months post-injury) to objectively measure the cognitive functioning, the Head Injury Symptom Checklist for subjective cognitive complaints, the Hospital Anxiety and Depression Scale for anxiety and depression, the Cognitive Reserve Index questionnaire for cognitive reserve, the Community Integration Questionnaire for community integration, and the Glasgow Outcome Scale Extended for functional outcome., Results: Cognitive impairments were observed in memory ( P < .001) and attention, processing speed and executive control ( P < .001). Cognitive reserve was not associated with neuropsychological test performance, except for one test measuring working memory. The relationship between injury severity and cognitive outcome was not moderated by cognitive reserve. Elderly patients reported significantly more complains than healthy controls regarding forgetfulness, concentration problems, and slowness. Complaints of concentration were associated with cognitive impairment. All cognitive complaints were significantly correlated with mental distress., Conclusions: Cognitive impairments may be present in elderly patients in the subacute phase after mTBI, and these impairments were not significantly associated with cognitive reserve. This suggests that cognitive reserve might not serve as a protective factor against the effects of mTBI in the elderly. Concentration complaints may serve as a specific indicator for cognitive impairment, while complaints of memory and mental slowness may represent more generic indicators of mental distress. These findings highlight the importance of careful screening in older adults with mTBI, guiding clinicians toward specific treatment targets encompassing cognitive impairment, diminished mental well-being, or both., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Wolters Kluwer Health, Inc.)

Objective: The majority of traumatic brain injuries (TBIs) are classified as mild and occur in young individuals. The course of recovery varies but can result in chronic or troubling outcomes. The impact of age on TBI outcomes in young adults before complete brain maturation is not well studied., Methods: In this study, we compared the effects of mild TBI on cognitive performance and self-reported TBI symptoms and posttraumatic stress disorder (PTSD) in 903 soldiers in 3 different age groups: 24 years or younger, 25 to 27 years, and 28 to 40 years. The soldiers had returned from war zones in Iraq and were screened for TBI within a few days of return. Cognitive performance was measured with the Automated Neuropsychological Assessment Metrics of Military TBI Version 4 (ANAM4). Symptoms associated with mild TBI were self-reported on the Neurobehavioral Symptom Inventory, and the PTSD Checklist-Civilian Version (PCL-C)., Results: Soldiers with TBI in every age group had significantly higher prevalence of most symptoms than those with no TBI. Soldiers with TBI also reported more chronic pain sites, regardless of age. Soldiers aged 28 to 40 years with TBI had the lowest cognitive performance scores (ANAM) across several subtests, both unadjusted and adjusted. The Global Deficit Score was significantly higher for soldiers aged 28 to 40 years and 25 to 27 years with TBI than for soldiers younger than 24 years with no TBI. After adjusting for PTSD symptoms, education, and number of lifetime TBIs, the overall test battery mean for soldiers aged 28 to 40 years with TBI was significantly lower than for soldiers younger than 24 years with no TBI., Conclusion: Soldiers with mild TBI in the younger age group show more symptoms associated to frontal lobe function while soldiers in the older group suffer more cognitive impairment. This may warrant further study as it may indicate a propensity to later cognitive decline among soldiers who were older at the time of injury., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Following mild traumatic brain injury (mTBI), children show reduced processing speed (PS). Evidence suggests that slowed PS after TBI is associated with working memory deficits. Our aim was to investigate several forms of PS and to examine its impact on working and episodic memory performance in children after mTBI., Method: We included data of 64 children after mTBI and 57 healthy control children aged 8-16 years. PS (Color Naming, Coding, Symbol Search, Alertness) was compared between groups 1 week (T1) and 3-6 months (T2) after the injury; working and episodic memory outcome was compared between groups at T2., Results: Alertness at T1 and Color Naming at T1 and T2 were significantly reduced following mTBI compared to controls, although most group differences in PS disappeared when patients with previous impairments and mTBI were excluded. PS was predictive for episodic and working memory performance 3-6 months after injury, whereas group was a significant predictor of working memory., Conclusions: Compared to healthy controls, children after mTBI showed reduced performance in verbal PS, which was associated with working memory. In children who are symptomatic after mTBI, diagnostic screening of PS could be helpful in identifying patients that could profit from speed-improving strategies.

Individuals with mild traumatic brain injury (mTBI) often complain of executive functioning (EF) difficulties. There is a discrepancy between self-reported EF impairment and EF deficits on neuropsychological tests, with some arguing that self-report EF is more related to real-world functioning than EF tests. However, research suggests that self-reported EF may be related more to emotional distress and is vulnerable to invalid reporting. We examined the vulnerability of the short form Barkley Deficits in Executive Functioning Scale (BDEFS) to invalid reporting, using a simulated mTBI paradigm. We included four groups: individuals simulating mTBI with (N = 24) and without (N = 21) histories of mTBI/other psychological conditions and controls with (N = 21) and without (N = 25) histories of mTBI/other psychological conditions. As hypothesized, simulators performed worse on the BDEFS Total Score and EF Symptom Count relative to controls; however, this effect was larger within those who had no self-reported history of mTBI/other psychological conditions. We identified a preliminary cutoff on the EF Symptom Count that detected 42.8% of simulators, with 95% specificity relative to the controls with histories of mTBI/other psychological conditions. The present study emphasizes the need for validity scales on self-report EF measures such as the BDEFS.

Objectives: Pain is still a neglected problem in mild traumatic brain injury (mTBI). In this cross-sectional study, we examined the frequency of musculoskeletal pain in a sample of adult patients with persistent cognitive symptoms after mTBI and whether pain level affected cognition., Methods: The participants were 23 adult patients aged 18-50 referred to brain injury rehabilitation clinics for neuropsychological assessment after having sustained an mTBI. A non-injured control group ( n = 29) was recruited through advertisements. The patients were, on average, assessed 22 months after trauma. All participants completed a comprehensive neuropsychological test battery and completed the Örebro Musculoskeletal Pain Screening Questionnaire, The Rivermead Post-Concussion Symptoms Questionnaire, and the State-Trait Anxiety Inventory., Results: Patients reported high levels of current pain and significantly more frequent neck and shoulder pain than the non-injured controls. Patients also reported high post-concussive symptoms and anxiety levels and performed less well on several neuropsychological tests. Pain level was associated with slower processing speed among the controls but not related to performance in the mTBI group., Conclusion: We conclude that musculoskeletal pain is frequent in mTBI patients referred to rehabilitation settings. Furthermore, the results indicate that the interaction between pain and cognitive functioning differs in mTBI compared to controls. Our results implicate that pain screening should be an integrated part of neuropsychological rehabilitation after mTBI to identify conditions that run the risk of becoming chronic. The study was approved by the Regional Ethical Board in Stockholm, Sweden (04-415/2)., (© 2024 the author(s), published by De Gruyter.)

Objectives: To investigate the relation between cognitive and motor performance in individuals with mild traumatic brain injury (mTBI) and examine differences in both cognitive and motor performance between adults after mTBI and healthy controls., Design: Multi-center, cross-sectional study., Setting: Three institutional sites (Courage Kenny Research Center, Minneapolis, MN, Oregon Health & Science University, Portland, OR, and University of Utah, Salt Lake City, UT)., Participants: Data were collected from 110 participants (N=110), including those with mTBI and healthy controls, who completed cognitive and physical performance assessments., Interventions: Not applicable., Outcome Measures: Cognitive assessments involved the Automated Neuropsychological Assessment Metrics to evaluate domains of attention, memory, reaction time, processing speed, and executive function. Physical performance was evaluated through clinical performance assessments, such as the 1-min walk test, the modified Illinois Agility Test, the Functional Gait Assessment Tool, the High-Level Mobility Assessment Tool, a complex turning course, and a 4-Item Hybrid Assessment of Mobility for mTBI. Participants also completed additional trials of the 1-min walk test, modified Illinois Agility Test, and complex turning course with a simultaneous cognitive task., Results: Individuals with mTBI performed worse on cognitive assessments, as well as several of the physical performance assessments compared with healthy controls. Complex tasks were more strongly related to cognitive assessments compared with simple walking tasks., Conclusions: Combining complex motor tasks with cognitive demands may better demonstrate functional performance in individuals recovering from mTBI. By understanding the relation between cognitive and physical performance in individuals recovering from mTBI, clinicians may be able to improve clinical care and assist in return to activity decision-making., (Copyright © 2023 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Background and Objectives: Traumatic brain injury (TBI) is a concern for US service members and veterans (SMV), leading to heterogeneous psychological and cognitive outcomes. We sought to identify neuropsychological profiles of mild TBI (mTBI) and posttraumatic stress disorder (PTSD) among the largest SMV sample to date., Methods: We analyzed cross-sectional baseline data from SMV with prior combat deployments enrolled in the ongoing Long-term Impact of Military-relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium prospective longitudinal study. Latent profile analysis identified symptom profiles using 35 indicators, including physical symptoms, depression, quality of life, sleep quality, postconcussive symptoms, and cognitive performance. It is important to note that the profiles were determined independently of mTBI and probable PTSD status. After profile identification, we examined associations between demographic variables, mTBI characteristics, and PTSD symptoms with symptom profile membership., Results: The analytic sample included 1,659 SMV (mean age 41.1 ± 10.0 years; 87% male); among them 29% (n = 480) had a history of non-deployment-related mTBI only, 14% (n = 239) had deployment-related mTBI only, 36% (n = 602) had both non-deployment and deployment-related mTBI, and 30% (n = 497) met criteria for probable PTSD. A 6-profile model had the best fit, with separation on all indicators ( p < 0.001). The model revealed distinct neuropsychological profiles, representing a combination of 3 self-reported functioning patterns: high (HS), moderate (MS), and low (LS), and 2 cognitive performance patterns: high (HC) and low (LC). The profiles were (1) HS/HC: n=301, 18.1%; (2) HS/LC: n=294, 17.7%; (3) MS/HC: n=359, 21.6%; (4) MS/LC: n=316, 19.0%; (5) LS/HC: n=228, 13.7%; and (6) LS/LC: n=161, 9.7%. SMV with deployment-related mTBI tended to be grouped into lower functioning profiles and were more likely to meet criteria for probable PTSD. Conversely, SMV with no mTBI exposure or non-deployment-related mTBI were clustered in higher functioning profiles and had a lower likelihood of meeting criteria for probable PTSD., Discussion: Findings suggest varied symptom and functional profiles in SMV, influenced by injury context and probable PTSD comorbidity. Despite diagnostic challenges, comprehensive assessment of functioning and cognition can detect subtle differences related to mTBI and PTSD, revealing distinct neuropsychological profiles. Prioritizing early treatment based on these profiles may improve prognostication and support efficient recovery.

Background: There lacks rapid standardized bedside testing to screen cognitive deficits following mild traumatic brain injury (mTBI). Immediate Post-Concussion Assessment & Cognitive Testing-Quick Test (ImPACT-QT) is an abbreviated-iPad form of computerized cognitive testing. The aim of this study is to test ImPACT-QT utility in inpatient settings. We hypothesize ImPACT-QT is feasible in the acute trauma setting., Method: Trauma patients ages 12-70 were administered ImPACT-QT (09/2022-09/2023). Encephalopathic/medically unstable patients were excluded. Mild traumatic brain injury was defined as documented-head trauma with loss-of-consciousness <30 minutes and arrival Glasgow Coma Scale 13-15. Patients answered Likert-scale surveys. Bivariate analyses compared demographics, attention, motor speed, and memory scores between mTBI and non-TBI controls. Multivariable logistic regression assessed memory score as a predictor of mTBI diagnosis., Results: Of 233 patients evaluated (36 years [IQR 23-50], 71% [166/233] female), 179 (76%) were mTBI patients. For all patients, mean test-time was 9.3 ± 2 minutes with 93% (73/76) finding the test "easy to understand." Mild traumatic brain injury patients than non-TBI control had lower memory scores (25 [IQR 7-100] vs 43 [26-100], P = .001) while attention (5 [1-23] vs 11 [1-32]) and motor score (14 [3-28] vs 13 [4-32]) showed no significant differences. Multivariable-regression (adjustment: age, sex, race, education level, ISS, and time to test) demonstrated memory score predicted mTBI positive status (OR .96, CI .94-.98, P = .004)., Discussion: Immediate Post-Concussion Assessment & Cognitive Testing-Quick Test is feasible in trauma patients. Preliminary findings suggest acute mTBIs have lower memory but not attention/motor scores vs non-TBI trauma controls., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Introduction: Mild traumatic brain injury (mTBI), depression, and PTSD are highly prevalent in post-9/11 veterans. With the comorbidity of depression and PTSD in post-9/11 veterans with mTBI histories and their role in exacerbating cognitive and emotional dysfunction, interventions addressing cognitive and psychiatric functioning are critical. Compensatory Cognitive Training (CCT) is associated with improvements in prospective memory, attention, and executive functioning and has also yielded small-to-medium treatment effects on PTSD and depressive symptom severity. We sought to examine neuropsychological correlates of PTSD and depressive symptom improvement in veterans with a history of mTBI who received CCT., Materials and Methods: Thirty-seven post-9/11 veterans with mTBI histories and cognitive complaints received 10 weekly 120-minute CCT group sessions. Participants completed a baseline neuropsychological assessment, including tests of premorbid functioning, attention/working memory, processing speed, verbal learning/memory, and executive functioning, and completed psychiatric symptom measures (PTSD and depression) at baseline, post-treatment, and a 5-week follow-up. Paired samples t-tests were used to examine statistically significant changes in PTSD (total and symptom cluster scores) and depressive symptom scores over time. Pearson's correlations were calculated between neuropsychological scores and PTSD and depressive symptom change scores at post-treatment and follow-up. Neuropsychological measures identified as significantly correlated with psychiatric symptom change scores were entered as independent variables in multivariable regression analyses to examine their association with symptom change at post-treatment and follow-up., Results: Over 50% of CCT participants had clinically meaningful improvement in depressive symptoms (≥17.5% score reduction), and over 20% had clinically meaningful improvement in PTSD symptoms (≥10-point improvement) at post-treatment and follow-up. Examination of PTSD symptom cluster scores revealed a statistically significant improvement in avoidance/numbing at follow-up. Bivariate correlations indicated that worse baseline performance on Category Fluency was moderately associated with PTSD symptom improvement at post-treatment. Worse performance on both Category Fluency and Category Switching Accuracy was associated with improvement in depressive symptoms at post-treatment and follow-up. Worse performance on Trail-Making Number-Letter Switching was also associated with improvement in depressive symptoms at follow-up. Subsequent regression analyses revealed that worse processing speed and worse aspects of executive functioning at baseline were associated with depressive symptom improvement at post-treatment and follow-up., Conclusions: Worse baseline performances on tests of processing speed and aspects of executive functioning were significantly associated with improvements in PTSD and depressive symptoms during the trial. Our results suggest that cognitive training may bolster skills that are helpful for PTSD and depressive symptom reduction and that those with worse baseline functioning may benefit more from treatment because they have more room to improve., (Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2023. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Introduction: Many commonly employed performance validity tests (PVTs) are several decades old and vulnerable to compromise, leading to a need for novel instruments. Because implicit/non-declarative memory may be robust to brain damage, tasks that rely upon such memory may serve as an effective PVT. Using a simulation design, this experiment evaluated whether novel tasks that rely upon perceptual memory hold promise as PVTs., Method: Sixty healthy participants were provided instructions to simulate symptoms of mild traumatic brain injury (TBI), and they were compared to a group of 20 honest responding individuals. Simulator groups received varying levels of information concerning TBI symptoms, resulting in naïve, sophisticated, and test-coached groups. The Word Memory Test, Test of Memory Malingering, and California Verbal Learning Test-II Forced Choice Recognition Test were administered. To assess perceptual memory, selected images from the Gollin Incomplete Figures and Mooney Closure Test were presented as visual perception tasks. After brief delays, memory for the images was assessed., Results: No group differences emerged on the perception trials of the Gollin and Mooney figures, but simulators remembered fewer images than the honest responders. Simulator groups differed on the standard PVTs, but they performed equivalently on the Gollin and Mooney figures, implying robustness to coaching. Relying upon a criterion of 90% specificity, the Gollin and Mooney figures achieved at least 90% sensitivity, comparing favorably to the standard PVTs., Conclusions: The Gollin and Mooney figures hold promise as novel PVTs. As perceptual memory tests, they may be relatively robust to brain damage, but future research involving clinical samples is necessary to substantiate this assertion.

Introduction: Self-reported memory difficulties (forgetting familiar names, misplacing objects) often persist long after a mild traumatic brain injury (mTBI), despite normal neuropsychological test performance. This clinical presentation may be a manifestation of a functional cognitive disorder (FCD). Several mechanisms underlying FCD have been proposed, including metacognitive impairment, memory perfectionism, and misdirected attention, as well as depression or anxiety-related explanations. This study aims to explore these candidate perpetuating factors in mTBI, to advance our understanding of why memory symptoms frequently persist following mTBI., Methods: A cross-sectional study of 67 adults (n = 39 with mTBI mean = 25 months ago and n = 28 healthy controls). Participants completed standardized questionnaires (including the Functional Memory Disorder Inventory), a metacognitive task (to quantify discrepancies between their trial-by-trial accuracy and confidence), and a brief neuropsychological test battery. We assessed candidate mechanisms in two ways: (1) between-groups, comparing participants with mTBI to healthy controls, and (2) within-group, examining their associations with functional memory symptom severity (FMDI) in the mTBI group., Results: Participants with mTBI performed similarly to controls on objective measures of memory ability but reported experiencing much more frequent memory lapses in daily life. Contrary to expectations, metacognitive efficiency did not differentiate the mTBI and control groups and was not associated with functional memory symptoms. Memory perfectionism was strongly associated with greater functional memory symptoms among participants with mTBI but did not differ between groups when accounting for age. Depression and checking behaviors produced consistent results across between-groups and within-group analyses: these factors were greater in the mTBI group compared to the control group and were associated with greater functional memory symptoms within the mTBI group., Conclusions: This study highlights promising (e.g., depression, checking behaviors) and unlikely (e.g., metacognitive impairment) mechanisms underlying functional memory symptoms after mTBI, to guide future research and treatment.

This study is the first to examine cognitive outcomes after pediatric mild TBI using the National Institutes of Health Toolbox Cognition Battery (NIHTB-CB), a computerized cognitive test battery. The NIHTB-CB includes two complex measures of attention and executive function that allow differentiation of accuracy and response speed. We compared performance on the NIHTB-CB among children 8-16 years of age with mild TBI ( n  = 143) versus children with orthopedic injuries (OIs; n  = 74) recruited in emergency departments and followed for 6 months post-injury. Mixed-model analyses showed that the mild TBI group showed significantly lower Fluid Cognition composite scores than the OI group at 10 days (group intercept, p  = 0.018); the magnitude of group differences declined modestly over time (group × time interaction, p  = 0.055). Effect sizes were d  = 0.34 at 10 days post-injury, d  = 0.27 at 3 months, and d  = 0.10 at 6 months. No significant effects of group or time were found for the Crystallized Cognition composite. Analyses of Fluid Cognition subtests indicated that children with mild TBI displayed deficits for as long as 3 months on measures of attention and executive function (e.g., cognitive flexibility, inhibitory control), but not on measures of explicit memory, working memory, or processing speed. The poorer performance of the mild TBI group on measures of attention and executive function was attributable largely to slowed reaction time, not decreased accuracy. The findings suggest that children with mild TBI demonstrate persistent deficits in fluid cognition that are most apparent on tasks that combine demands for both speed and executive function.

This study investigates subacute cognitive effects of mild traumatic brain injury (MTBI) in the Trondheim Mild TBI Study, as measured, in part, by the neuropsychological test battery of the Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI) program, including computerized tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB) and traditional paper-and-pencil tests. We investigated whether cognitive function was associated with injury severity: intracranial traumatic lesions on neuroimaging, witnessed loss of consciousness (LOC), or post-traumatic amnesia (PTA) >1 h. Further, we explored which of the tests in the CENTER-TBI battery might be associated with the largest subacute effects of MTBI (i.e., at 2 weeks post-injury). We recruited 177 patients with MTBI (16-59 years of age) from a regional trauma center and an outpatient clinic,79 trauma control participants, and 81 community control participants. The MTBI group differed from community controls only on one traditional test of processing speed (coding; p  = 0.009, Cliff's delta [Δ] = 0.20). Patients with intracranial abnormalities performed worse than those without on a traditional test (phonemic verbal fluency; p  = 0.043, Δ = 0.27), and patients with LOC performed differently on the Attention Switching Task from the CANTAB ( p  = 0.020, Δ = -0.20). Patients with PTA >1 h performed worse than those with <1 h on 10 measures, from traditional tests and the CANTAB (Δ = 0.33-0.20), likely attributable, at least in part, to pre-existing differences in intellectual functioning between groups. In general, those with MTBI had good neuropsychological outcome 2 weeks after injury and no particular CENTER-TBI computerized or traditional tests seemed to be more sensitive to subtle cognitive deficits.

Background: Traumatic brain injury (TBI) is a known risk factor for neurodegenerative dementias such as Alzheimer disease (AD); however, the potential risk of mild cases of TBI, such as concussions, remains unclear., Objective: To explore whether a small sample of retired professional athletes with a diagnosis of mild cognitive impairment (MCI)-the prodromal stage of AD-and a history of multiple mild TBIs exhibit greater neuropsychological impairment than age-matched nonathletes with MCI and no history of TBI., Method: Ten retired National Football League players diagnosed with MCI and reporting multiple mild TBIs, and 10 nonathletes, also diagnosed with MCI but with no history of TBI, completed a standard neurologic examination and neuropsychological testing. Independent samples t tests were conducted to examine differences in neuropsychological performance between the two groups., Results: The retired athletes with a history of mild TBI obtained generally similar scores to the nonathlete controls on measures of verbal learning and memory, verbal fluency, and processing speed. However, the retired athletes scored lower than the controls on tests of confrontation naming and speeded visual attention., Conclusion: Retired athletes with MCI and a history of mild TBI demonstrated similar neuropsychological profiles as nonathlete controls despite lower scores on measures of confrontation naming and speeded visual attention. These findings suggest that a history of multiple mild TBIs does not significantly alter the overall neuropsychological profile of individuals with MCI; confirmation of this will require longitudinal research with larger sample sizes.

Objective: Since neurocognitive functioning following mild traumatic brain injury (mTBI) may be influenced by genetic factors that mediate synaptic survival and repair, we examined the influence of a common brain-derived neurotrophic factor (BDNF) polymorphism (Val66Met) on cognition using a well-defined sample of military Veterans with and without a history of mTBI., Method: Participants included 138 Veterans (mTBI = 75; military controls [MCs] = 63) who underwent neuropsychological testing, including completion of self-report measures assessing psychiatric distress, and BDNF genotyping. The mTBI group was tested roughly 66.7 months following their most recent mTBI. Veterans were divided into two groups-Met+ (Met/Met and Met/Val; n = 49) and Met- (Val/Val; n = 89) and compared on domain-specific cognitive composite scores representing memory, executive functioning, and visuospatial speed., Results: ANCOVAs adjusting for psychiatric distress, sex, years of education, and ethnicity/race revealed a significant group (mTBI vs. MC) by BDNF genotype (Met + vs. Met-) interaction for the memory ( p  = .024; η p 2  = .039) and executive functioning ( p  = .010; η p 2  = .050) composites, such that Met+ mTBI Veterans demonstrated better performance than Met- mTBI Veterans on the cognitive measures, whereas Met+ MCs demonstrated worse performance relative to Met- MCs on the cognitive measures. No significant interaction was observed for the visuospatial speed composite ( p  = .938; η p 2  < .001)., Conclusions: These findings offer preliminary evidence to suggest that the Met allele may be protective in the context of remote mTBI. Findings need to be replicated using larger samples, and future studies are necessary to elucidate the precise mechanisms and neural underpinnings of this interaction.

Objective: The purpose of this study was to examine individual postconcussion symptom [PCSx] trajectories following mild traumatic brain injury (MTBI), and to examine risk factors for persistent PCSx reporting., Method: Participants were 138 U.S. military service members and veterans (SMVs) prospectively enrolled in the Defense and Veterans Brain Injury Center, 15-Year Longitudinal TBI study. Participants were classified into three groups: uncomplicated MTBI (n = 54), injured controls (IC, n = 26), and non-injured controls (NIC, n = 58). Participants completed the Neurobehavioral Symptom Inventory, PTSD Checklist, and Traumatic Brain Injury Quality of Life at baseline (<8 months post-injury) and at follow-up (2-4 years post-injury)., Results: The prevalence of those who met DSM-IV-TR symptom criteria for Postconcussional Disorder (PCD) was high in all three groups (e.g., 44.8-63.0%) and did not significantly change from baseline to follow-up (all ps>.05). However, there was substantial variability in individual symptom trajectories over time. The majority of participants had symptom trajectories classified as either 'persistent' (∼32-55%) or 'asymptomatic' (∼30-36%), with a substantial minority classified as 'improved' (∼7-12%) or 'developed' (∼7-19%). Factors associated with 'persistent' PCD trajectories included cognitive complaints, PTSD, depression, anxiety, pain, and headaches at baseline; but not the presence/absence of MTBI. Factors associated with 'developed' PCD trajectories included PTSD and the number of lifetime exposures to blast. Conclusions: Reporting of 'new' PCSx over time was common in individuals with and without MTBI. It would be erroneous to assume uncritically that PCSx reported many years post-injury reflect only persistent symptomatology, or can be solely attributable to the direct consequences of a brain injury.

Objective: Prior research indicates that there is an additive association between traumatic brain injury and mental health diagnoses on health-care utilization. This assumed additivity has not been formally assessed. The objective of this study was to estimate additive and multiplicative interactions associated with mild traumatic brain injury (mTBI) and pre-existing health conditions., Method: Active-duty military patient records over a nine-year period were sampled within four exposure groups ( N  = 4500 per group) defined jointly by incident mTBI and pre-existing mental health diagnoses. Outpatient and inpatient health encounters were compared between the four exposure groups using generalized linear models for count and proportion outcomes. Additive interactions were estimated using the interaction contrast ratio. Multiplicative interactions were estimated as a product term in the generalized linear models., Results: The joint association of mTBI and pre-existing mental health diagnoses with health-care utilization, overall, was less than multiplicative and greater than additive. Patients with both exposures experienced more health-care utilization than expected under the assumed additivity (independence) of the two exposures. PTSD and anxiety diagnoses were the MH diagnoses associated with the largest interaction contrast values specific to total outpatient encounters., Conclusions: Studies of the interaction of two diagnoses on subsequent health-care utilization should examine both additive and multiplicative interactions. The greater-than-additive findings in this study indicate that there may be synergy, for at least some patients, between mTBI injury and mental health that complicates the treatment course.

Background: Mild traumatic brain injury (mTBI) is a putative risk factor for dementia; however, despite having apparent face validity, the evidence supporting this hypothesis remains inconclusive. Understanding the role of mTBI as a risk factor is becoming increasingly important given the high prevalence of mTBI, and the increasing societal burden of dementia., Objective: Our objective was to use the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) format to determine if an association exists between mTBI and dementia and related factors, and to quantify the degree of risk., Methods: In this format, two authors conducted independent database searches of PubMed, PsycInfo, and CINAHL using three search blocks to find relevant papers published between 2000 and 2020. Relevant studies were selected using pre-defined inclusion/exclusion criteria, and bias scoring was performed independently by the two authors before a subset of studies was selected for meta-analysis. Twenty-one studies met the inclusion criteria for this systematic review., Results: The meta-analysis yielded a pooled odds ratio of 1.96 (95% CI 1.698-2.263), meaning individuals were 1.96 times more likely to be diagnosed with dementia if they had a prior mTBI. Most studies examining neuropsychiatric and neuroimaging correlates of dementia found subtle, persistent changes after mTBI., Conclusion: These results indicate that mTBI is a risk factor for the development of dementia and causes subtle changes in performance on neuropsychiatric testing and brain structure in some patients.

Importance: Mild traumatic brain injury (TBI) may predispose individuals to progressive neurodegeneration., Objective: To identify evidence of neurodegeneration through longitudinal evaluation of changes in retinal layer thickness using optical coherence tomography in veterans with a history of mild TBI., Design, Setting, and Participants: This longitudinal cohort study evaluated veterans who were receiving services at the Minneapolis Veterans Affairs Health Care System. Symptomatic or mild TBI was diagnosed according to the Mayo TBI Severity Classification System. Participants in the age-matched control group had no history of TBI. Participants with any history or evidence of retinal or optic nerve disease that could affect retinal thickness were excluded. Data analysis was performed from July 2019 to February 2020., Exposures: The presence and severity of mild TBI were determined through consensus review of self-report responses during the Minnesota Blast Exposure Screening Tool semistructured interview., Main Outcomes and Measures: Change over time of retinal nerve fiber layer (RNFL) thickness., Results: A total of 139 veterans (117 men [84%]; mean [SD] age, 49.9 [11.1] years) were included in the study, 69 in the TBI group and 70 in the control group. Veterans with mild TBI showed significantly greater RNFL thinning compared with controls (mean [SE] RNFL slope, -1.47 [0.24] μm/y vs -0.31 [0.32] μm/y; F1,122 = 8.42; P = .004; Cohen d = 0.52). Functionally, veterans with mild TBI showed greater declines in visual field mean deviation (mean [SE] slope, -0.09 [0.14] dB/y vs 0.46 [0.23] dB/y; F1,122 = 4.08; P = .046; Cohen d = 0.36) and pattern standard deviation (mean [SE] slope, 0.09 [0.06] dB/y vs -0.10 [0.07] dB/y; F1,122 = 4.78; P = .03; Cohen d = 0.39) and high spatial frequency (12 cycles/degree) contrast sensitivity compared with controls. Cognitively, there was a significantly greater decrease in the number of errors over time during the Groton Maze Learning Test (GMLT) in controls compared with veterans with mild TBI (mean [SE] slope, -9.30 [1.48] errors/y vs -5.23 [1.24] errors/y; F1,127 = 4.43; P = .04; Cohen d = 0.37). RNFL tissue loss was significantly correlated with both worsening performance on the GMLT over time (Spearman ρ = -0.20; P = .03) and mild TBI severity (Spearman ρ = -0.25; P = .006). The more severe the mild TBI (larger Minnesota Blast Exposure Screening Tool severity score), the faster the reduction in RNFL thickness (ie, the more negative the slope) across time., Conclusions and Relevance: This cohort study found longitudinal evidence for significant, progressive neural degeneration over time in veterans with mild TBI, as indicated by greater RNFL tissue loss in patients with mild TBI vs controls, as well as measures of function. These results suggest that these longitudinal measures may be useful biomarkers of neurodegeneration. Changes in this biomarker may provide early detection of subsequent cognitive and functional deficits that may impact veterans' independence and need for care.

This study examined failure rates on the Nonverbal-Medical Symptom Validity Test (NV-MSVT) and its impact on cognitive performance in a sample of youths with mild traumatic brain injury (mTBI). Participants were 184 children and adolescents who presented to a multidisciplinary concussion clinic for a targeted neuropsychological evaluation. Performance Validity Tests (PVTs) were a part of the standard battery, including the NV-MSVT. Twenty-eight participants (15.2%) failed the NV-MSVT, none of whom displayed a genuine memory impairment profile (GMIP). Participants who failed the NV-MSVT performed significantly worse than those who passed the NV-MSVT on measures of IQ, memory, and immediate attention/working memory. There was no significant difference between groups on processing speed, sustained attention, cognitive flexibility, or sight word reading level. Aside from a slight difference in age, NV-MSVT failure was not impacted by demographic variables (sex, race), premorbid risk factors (pre-injury ADHD, learning disabilities, psychiatric diagnoses or treatment, developmental delays, or prior special education), injury-related variables (time since injury, positive neuroimaging findings, post-traumatic amnesia, number of prior mTBIs, etc.) or post-mTBI anxiety/depression. That said, participants who failed NV-MSVT endorsed significantly more severe postconcussive symptoms. These findings support the use of the NV-MSVT in neuropsychological evaluation of children and adolescents with mTBI.

Objective: In 2018, the Centers for Disease Control Prevention (CDC) published an evidence-based guideline on the diagnosis and management of mild traumatic brain injury (mTBI) among children. This commentary summarizes the key recommendations in the CDC Pediatric mTBI Guideline most relevant for neuropsychologists and discusses research gaps and topics that should receive attention in future iterations of the Guideline. Method: We described the methods used to develop the Guideline, which included a comprehensive Systematic Review. We also distilled and presented key practice strategies reflected in Guideline. Results: To optimize care of pediatric patients with mTBI, neuropsychologists should: use validated, age-appropriate symptom scales, assess evidence-based risk factors for prolonged recovery, provide patients with instructions on return to activity customized to their symptoms, and counsel patients to return gradually to nonsports activities after a short period of rest. Future iterations of the Guideline should encompass a review and guidance on care of patients with psychiatric and psychological difficulties, as well as the potential use of imaging to assess patients with persistent symptoms. Expanded research on mTBI among girls, children age 8 and under, and effective treatments for pediatric mTBI will be beneficial to inform care practices. Conclusions: Recommendations in the CDC Pediatric mTBI Guideline highlight multiple opportunities for neuropsychologists to take action to improve the care of young patients with mTBI and to advance research in the field. Multiple resources and tools are available to support implementation of these recommendations into clinical practice.

Objective: Prospective memory (PM) is the ability to remember to perform an intention at the appropriate time in the future. It is of primary importance for daily living, and its disruption may impact functional autonomy. To date, few studies have examined PM during the acute phase of mild traumatic brain injury (mTBI), despite the high prevalence of this neurological condition and its potential impact on cognition. Method: Twenty mTBI patients (time since injury ranged from 45 to 73 days) and 15 healthy control participants performed the Ecological Test of Prospective Memory (TEMP), a simulated errand task in which participants were required to execute 10 event-based (EB) and five time-based (TB) tasks. The TEMP separately evaluates PM phases as well as prospective and retrospective components in event- and time-based conditions. Participants also completed a neuropsychological test battery. Correlations were performed between cognitive composite scores and the TEMP. Results: mTBI patients experienced difficulty in learning the content of intentions, retrieving these intentions in the time-based condition (prospective component) and recalling the associated actions in the event- and time-based conditions (retrospective component). Retrospective memory composite score was correlated with the learning and retention phases of the TEMP, whereas attention/working memory and executive composite scores were correlated with the time-based condition and performance on the ongoing task. Conclusion: These results suggest the presence of global PM impairment during the acute phase of mTBI, as well as impairment of retrospective memory, attention/working memory, and executive functions, which are key components for PM performance.

The development of more sophisticated performance validity measures is important due to concerns with coaching as well as providing clinicians with a greater variety of options when assessing performance validity. Examinees with noncredible performance may find it more difficult to elude detection by PVTs derived from arithmetical summation or logistic regression. The present study evaluated the classification accuracy of several executive functioning (EF) variables as PVTs both individually and when combined into derived variables. The current study evaluated a simple mathematic summation of embedded PVT scores and a logistic regression-based formula based on embedded PVTs from executive function measures. A total of 155 consecutive patients completed neuropsychological evaluation after sustaining a mild traumatic brain injury (MTBI) were studied and were placed into a PVT-PASS ( N  = 95, mean age = 44.9, SD  = 12.55, mean education = 13.45, SD  = 2.23, 38% male, 97% Caucasian) or PVT-FAIL group ( N  = 60, mean age = 44.1, SD  = 15.47, mean education = 13.05, SD  = 2.58, 55% male, 92% Caucasian). Trail Making Test B, Wisconsin Card Sorting Test, and Stroop Color Word Test were summed and also used in logistic regression to predict whether patients had credible performance. Both the mathematical summation and the logistic regression methods achieved excellent classification accuracy (summation AUC = .79; logistic regression AUC = .82) with higher sensitivity than individual PVTs.

Objective: The current study examined the effect of depression on cognitive test performance in a sample of adults seeking treatment for a mild traumatic brain injury (MTBI). We hypothesized that patients with greater depressive symptoms would perform worse on tasks of fluid cognition compared to those without depression, after controlling for potential confounds., Method: Patients (N = 76) completed a brief cognitive test battery (NIH Toolbox Cognition Battery; NIHTB-CB) and a depression screening questionnaire (PHQ-9) at 11.7-weeks post injury (SD = 6.3 range 2-26). Cognitive scores were adjusted for age, education, gender, and race/ethnicity. Depressive symptoms were examined continuously and dichotomized as: (1) total PHQ-9 score of ≥ 10, the optimal cut-off for Major Depressive Disorder caseness from prior research, and (2) five or more symptoms of depression, including either depressed mood or anhedonia (i.e. DSM-5-based definition)., Results: Twenty-seven patients (35.5%) met DSM-5-based criteria for depression and 42 (55.3%) met criteria based on PHQ-9 > 10. Depression symptom severity correlated with lower fluid cognition composite scores [r = -.22, p = .05] and contributed to the prediction of fluid cognition performance in a model that controlled for time since injury and crystallized cognitive abilities [F(3, 72) = 7.49, p < .001; R 2  = 20.6%]. Examining specific NIHTB-CB fluid subtests, the largest group differences were seen on processing speed (d = .40-.49), cognitive flexibility (d = .32-.36), and episodic memory (d = .20-.34). Depression severity was strongly associated with overall post-concussion symptom burden (r = .77, p < .001)., Conclusion: Depression is a common comorbidity and an important factor to consider when interpreting neurocognitive test performance in adults with concussion in a clinical setting.

Objective: The Functional Status Examination (FSE) is a comprehensive measure of functional status post-traumatic brain injury (TBI) that has primarily been used in studies of moderate-to-severe TBI. The present observational study examines functional status using the FSE among patients who sustained mild TBIs (mTBIs; defined as Glasgow Coma Scale [GCS] = 13-15 at admission) seen in a Level 1 trauma center. Study aims included examining the course of functional status following mTBI, as well as exploring relationships of the FSE and other relevant constructs among those with GCS = 13-15., Method: Participants were assessed at 2 weeks (n = 112), 3 months (n = 113), 6 months (n = 106), and 12 months (n = 88) post-injury for changes in functional status resulting both (a) from all injuries and (b) from TBI only., Results: Among seven domains of day-to-day functioning, participants generally experienced the greatest disruption in their primary activity (work or school) and in leisure and recreation. Subjects' overall functional status tended to improve over time, with sharpest increases in functionality occurring in the first 3 months post-injury. However, some subjects continued to report functional limitations even at 12 months post-injury. Functional status was largely unrelated to neurocognitive functioning, but related strongly to post-traumatic symptoms, life satisfaction, and emotional well-being, particularly at 3 months post-injury and beyond., Conclusion: Findings indicate that functional impairments related to mTBI may be more likely to persist than widely believed, with those who experience lingering functional deficits at particular risk for emotional health difficulties., (© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Performance validity tests (PVT) should be used when assessing youth with mild traumatic brain injury (MTBI). The goal of this study was to derive a new cutscore for determining invalid performance on the Memory Validity Profile (MVP) in youth with MTBI. Children and adolescents ( N  = 92; mean age =14.8 years, SD  = 2.3, range =8-18) on average six months ( SD  = 3.6) post-MTBI were administered the MVP as part of their assessment. Two validated PVTs [Test of Memory Malingering (TOMM) and Medical Symptom Validity Test (MSVT)] were administered and used to group the sample into valid ( n  = 73, neither TOMM/MSVT failed) and invalid ( n  = 19, both TOMM/MSVT failed). New cutscores for the MVP to determine invalid performance in this sample were established using failure on both TOMM/MSVT as the criterion. MVP performance correlated significantly with failure on TOMM/MSVT. Youth with invalid performance had significantly lower MVP total scores and area under the curve was .80, suggesting good separation of groups. A cutscore of 31 or less on the MVP provided sensitivity of 63% for detecting invalid performance with 93% specificity. This study yields a promising new cutscore for the MVP that has good sensitivity and strong specificity for detecting invalid performance in youth with MTBI.

Background: Development of an embedded performance validity test (PVT) is desired for visual memory tests. The goal of this study was to derive an embedded PVT for the Child and Adolescent Memory Profile (ChAMP) Objects visual memory subtest in youth with mild traumatic brain injury (MTBI)., Methods: Children and adolescents (N = 91; mean age = 14.9 years, SD = 2.2, range = 8-18) on average 25.2 weeks (SD = 15.4) post-MTBI were administered ChAMP Objects. Two stand-alone PVTs (Test of Memory Malingering and Medical Symptom Validity Test) were administered, which allowed for grouping into valid (zero failed stand-alone PVTs) and invalid (both stand-alone PVTs failed). Cutoff scores for invalid performance on ChAMP Objects and Objects Delayed were established using failure on two PVTs as the criterion., Results: One in five youth (n = 19) failed both PVTs. Invalid performance was not associated with demographics or time since injury, but was significantly correlated with both ChAMP Objects (r = .53, p<.001) and Objects Delayed (r = -.63, p<.001). Area under the curve suggested adequate discrimination by Objects (.87) and excellent discrimination by Objects Delayed (.91). A cutoff scaled score of 5 or less on ChAMP Objects provided sensitivity of 58% for detecting invalid performance with 96% sensitivity. A cutoff scaled score of 5 or less on ChAMP Objects Delayed achieved sensitivity of 63% and specificity of 96%. Interpreting the two embedded PVTs simultaneously improved sensitivity to 79% with 93% specificity., Conclusion: This study yields promising new embedded PVTs for the ChAMP Objects subtest with strong sensitivity and specificity for detecting invalid performance in youth with MTBI., (© The Author(s) 2018. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objective: The Automated Neuropsychological Assessment Metrics (Version 4) Traumatic Brain Injury Military (ANAM4 TBI-MIL) is commonly administered among U.S. service members both pre-deployment and following TBI. The current study used the ANAM4 TBI-MIL to develop a cognition summary score for TBI research and clinical trials, comparing eight composite scores based on their distributions and sensitivity/specificity when differentiating between service members with and without mild TBI (MTBI)., Method: Male service members with MTBI (n = 56; Mdn = 11 days-since-injury) or no self-reported TBI history (n = 733) completed eight ANAM4 TBI-MIL tests. Their throughput scores (correct responses/minute) were used to calculate eight composite scores: the overall test battery mean (OTBM); global deficit score (GDS); neuropsychological deficit score-weighted (NDS-W); low score composite (LSC); number of scores <50th, ≤16th percentile, or ≤5th percentile; and the ANAM Composite Score (ACS)., Results: The OTBM and ACS were normally distributed. Other composites had skewed, zero-inflated distributions (62.9% had GDS = 0). All composites differed significantly between participants with and without MTBI (p < .001), with deficit scores showing the largest effect sizes (d = 1.32-1.47). The Area Under the Curve (AUC) was lowest for number of scores ≤5th percentile (AUC = 0.653) and highest for the LSC, OTBM, ACS, and NDS-W (AUC = 0.709-0.713)., Conclusions: The ANAM4 TBI-MIL has no well-validated composite score. The current study examined multiple candidate composite scores, finding that deficit scores showed larger group differences than the OTBM, but similar AUC values. The deficit scores were highly correlated. Future studies are needed to determine whether these scores show less redundancy among participants with more severe TBIs., (© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: The purpose of this study was to investigate the effect of the apolipoprotein E (APOE) ε4 allele on neuropsychological functioning in military Veterans with a remote history of mild traumatic brain injury (mTBI)., Method: This cross-sectional study included 99 Veterans (mTBI = 53; military controls, MC = 46) who underwent neuropsychological assessment and APOE genotyping. Three neurocognitive composite scores-memory (α = .84), speed (α = .85), and executive functioning (α = .76)-were computed from 24 norm-referenced variables, and the total number of impaired scores (>1.5 SDs below mean) for each participant was calculated., Results: Analyses of covariance adjusting for ethnicity and posttraumatic stress disorder (PTSD) symptoms revealed that although no significant differences were observed between mTBI ε4 allele groups on the executive functioning composite (p > .05), mTBI ε4+ Veterans performed more poorly than ε4- Veterans on the memory (p = .045, η p 2  = .083) and speed (p = .023, η p 2  = .106) composites. Furthermore, Mann-Whitney U tests showed that ε4+ mTBI Veterans displayed a significantly greater number of impaired scores than did ε4- mTBI Veterans (p = .010, r = .355). In contrast, there were no significant differences across any of the cognitive variables between ε4+ and ε4- MCs (all p > .05)., Conclusions: Results suggest that APOE ε4 genotype is related to reduced memory and processingspeed performance, as well as overall cognitive impairment, in those with a history of mTBI, but does not appear to have the same negative effects on cognition in the absence of neurotrauma. Although results are preliminary, the present study advances understanding of genetic influences on cognitive functioning in Veterans with remote mTBIs. Future longitudinal work is needed to elucidate the underlying brain-based mechanisms of ε4 allelic effects on cognitive and clinical outcomes following TBI.

Objective: This study's aim was to investigate the features and neural mechanisms of sustained attention in patients with mild traumatic brain injury (mTBI) by comparing and analyzing neuropsychological, behavioral, event-related potentials, and event-related desynchronization and synchronization between mTBI patients and healthy controls., Methods: Twenty mTBI patients with mTBI and 20 healthy controls underwent the Mini-Mental State Examination (MMSE) and a cued continuous performance task (AX-CPT). Neuropsychological, behavioral, and electroencephalogram (EEG) data were collected and analyzed., Results: There were significant differences between the mTBI group and the control group in their MMSE total scores, attention, and calculation, but there were no significant differences in orientation, memory, recall, and verbal scores. There were significant differences between the mTBI group and the control group in hitting the number, reaction time, and the number of errors of omission, but there were no significant differences in the number of false errors. The amplitude of Go-N2 and Nogo-N2 was significantly smaller for the mTBI group than that for the control group. The amplitude of Go-P3 was significantly smaller for the mTBI group than that for the control group, but not for the amplitude of Nogo-P3. The Go-αERS were significantly less for the mTBI group than for the control group during the 0-200 ms after the stimulus onset. The Go-αERD and Nogo-αERD were significantly less for the mTBI group than for the control group during the 600-1,000 ms after the stimulus onset. The Go-βERS were significantly less for the mTBI group than for the control group during the 200-400 ms after the stimulus onset. There were no significant differences in the Nogo-αERS and Nogo-βERD/ERS between the mTBI group and the control group., Conclusion: Patients with mTBI exhibited impairments in sustained attention and conflict monitoring, while response inhibition may have been spared.

Objective: Computerized neurocognitive assessment tools (NCATS) are often used as a screening tool to identify cognitive deficits after mild traumatic brain injury (mTBI). However, differing methodology across studies renders it difficult to identify a consensus regarding the validity of NCATs. Thus, studies where multiple NCATs are administered in the same sample using the same methodology are warranted., Method: We investigated the validity of four NCATs: the ANAM4, CNS-VS, CogState, and ImPACT. Two NCATs were randomly assigned and a battery of traditional neuropsychological (NP) tests administered to healthy control active duty service members (n = 272) and to service members within 7 days of an mTBI (n = 231). Analyses included correlations between NCAT and the NP test scores to investigate convergent and discriminant validity, and regression analyses to identify the unique variance in NCAT and NP scores attributed to group status. Effect sizes (Cohen's f2) were calculated to guide interpretation of data., Results: Only 37 (0.6%) of the 5,655 correlations calculated between NCATs and NP tests are large (i.e. r ≥ 0.50). The majority of correlations are small (i.e. 0.30 > r ≥ 0.10), with no clear patterns suggestive of convergent or discriminant validity between the NCATs and NP tests. Though there are statistically significant group differences across most NCAT and NP test scores, the unique variance accounted for by group status is minimal (i.e. semipartial R2 ≤ 0.033, 0.024, 0.062, and 0.011 for ANAM4, CNS-VS, CogState, and ImPACT, respectively), with effect sizes indicating small to no meaningful effect., Conclusion: Though the results are not overly promising for the validity of the four NCATs we investigated, traditional methods of investigating psychometric properties may not be appropriate for computerized tests. We offer several conceptual and methodological considerations for future studies regarding the validity of NCATs., (© The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Individuals with traumatic brain injury (TBI) present with numerous discourse deficits associated with impairments to the linguistic system and other cognitive systems. Individuals with TBI may produce discourse that is lacking important information and poorly organized, as well as containing numerous coherence disrupting elements. Yet there are few studies directly addressing discourse deficits in individuals with TBI to guide clinicians., Aims: The purpose of the study was to determine if discourse processing treatment improved the discourse production in individual with TBI. Aims of the study included determining if the discourse processing treatment improved completeness and informativeness in TBI discourse samples., Methods & Procedures: The study included three participants with mild-to-moderate TBI. The study utilized an A-B with maintenance design that incorporated components of functional practice, structured cues in the form of comprehension questions and story guide, and meta-cognitive and meta-linguistic processes. Discourse samples were obtained for baseline, treatment, and maintenance one-week and one-month post treatment. Stimuli included 12 sequential pictures, as well as a single picture and a recount probe., Outcomes & Results: All participants demonstrated small gains in completeness and informativeness for treated items, and 2 of 3 participants demonstrated a medium therapeutic effect for untreated stimuli. Participants also produced discourse with fewer errors for both treated and untreated stimuli after treatment with no therapeutic effect to a small effect for the generalization stimuli., Conclusions: The study demonstrated that the discourse processing treatment is capable of producing small therapeutic effects that persisted one-month post treatment in adults with mild-to-moderate TBI., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Although across-test intra-individual variability (IIV), or dispersion, has been shown to be a valuable marker of neurological health in a variety of clinical samples, IIV has not been well examined in the context of mild traumatic brain injury (mTBI). In the present study, we examined measures of IIV in military Veterans with and without a history of mTBI. Secondly, we examined how measures of IIV relate to traditional indices of mean cognitive performance, TBI characteristics, and neuropsychiatric symptoms in mTBI. Participants included 120 Veterans (67 mTBI, 53 military controls [MCs]) who completed a comprehensive neuropsychological assessment. Two dispersion indices were calculated using 13 norm-referenced variables: an average standard deviation (ASD) score and a maximum discrepancy (MD) score. Compared to MCs, Veterans with a history of mTBI demonstrated greater IIV as indicated by the MD index after adjusting for relevant demographic variables, PTSD symptoms, and mean-level cognitive performance (p = 0.027; η p 2 = 0.025). Among the mTBI participants, the two IIV indices were positively correlated with each other (p < 0.001, r = 0.921) and negatively correlated with mean cognitive performance (p = 0.017-0.022, r = -[0.279-0.291]). In contrast, ASD and MD scores were not associated with a measure of premorbid intellectual functioning or neuropsychiatric symptoms (all p's > 0.05). However, higher ASD scores were positively related to lifetime number of mTBIs, such that greater cognitive variability was observed in Veterans with a history of multiple mTBIs (i.e., ≥3 mTBIs; p = 0.037, r = 0.255). Overall, our results demonstrate that Veterans with mTBI show greater IIV relative to MCs, and that repetitive mTBI is associated with increased cognitive performance variability. Findings indicate that, in the context of mTBI-which is considerably heterogeneous in nature-measures of dispersion may be more appropriate indicators of cognitive dysfunction when compared to traditional mean neuropsychological scores, especially in those with remote mTBI histories. Future longitudinal studies are needed to further establish the long-term clinical implications and brain-based correlates of these findings.p 2 = 0.025). Among the mTBI participants, the two IIV indices were positively correlated with each other (p < 0.001, r = 0.921) and negatively correlated with mean cognitive performance (p = 0.017-0.022, r = -[0.279-0.291]). In contrast, ASD and MD scores were not associated with a measure of premorbid intellectual functioning or neuropsychiatric symptoms (all p's > 0.05). However, higher ASD scores were positively related to lifetime number of mTBIs, such that greater cognitive variability was observed in Veterans with a history of multiple mTBIs (i.e., ≥3 mTBIs; p = 0.037, r = 0.255). Overall, our results demonstrate that Veterans with mTBI show greater IIV relative to MCs, and that repetitive mTBI is associated with increased cognitive performance variability. Findings indicate that, in the context of mTBI-which is considerably heterogeneous in nature-measures of dispersion may be more appropriate indicators of cognitive dysfunction when compared to traditional mean neuropsychological scores, especially in those with remote mTBI histories. Future longitudinal studies are needed to further establish the long-term clinical implications and brain-based correlates of these findings., (Published by Elsevier Ltd.)

Objective: To examine the influence of different performance validity test (PVT) cutoffs on neuropsychological performance, post-concussion symptoms, and rates of neurocognitive disorder and postconcussional syndrome following mild traumatic brain injury (MTBI) in active duty service members., Method: Participants were 164 service members (Age: M = 28.1 years [SD = 7.3]) evaluated on average 4.1 months (SD = 5.0) following injury. Participants were divided into three mutually exclusive groups using original and alternative cutoff scores on the Test of Memory Malingering (TOMM) and the Effort Index (EI) from the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS): (a) PVT-Pass, n = 85; (b) Alternative PVT-Fail, n = 53; and (c) Original PVT-Fail, n = 26. Participants also completed the Neurobehavioral Symptom Inventory., Results: The PVT-Pass group performed better on cognitive testing and reported fewer symptoms than the two PVT-Fail groups. The Original PVT-Fail group performed more poorly on cognitive testing and reported more symptoms than the Alternative PVT-Fail group. Both PVT-Fail groups were more likely to meet DSM-5 Category A criteria for mild and major neurocognitive disorder and symptom reporting criteria for postconcussional syndrome than the PVT-Pass group. When alternative PVT cutoffs were used instead of original PVT cutoffs, the number of participants with valid data meeting cognitive testing criteria for neurocognitive disorder or postconcussional syndrome decreased dramatically., Conclusion: PVT performance is significantly and meaningfully related to overall neuropsychological outcome. By using only original cutoffs, clinicians and researchers may miss people with invalid performances.

Background: Traditionally, the diagnosis of postural instability relies on the clinical examination of static balance. In recent years, computerized technologies have provided a new approach for the accurate detection of positional changes during functional balance., Aim: The aim of this study was to investigate the similarities and differences between two electronic systems, NeuroCom and BioSensics , and their application in the clinical assessment of impaired balance in American veterans., Materials and Methods: We examined the sway around the center of mass during static balance conditions in 25 veterans with mild traumatic brain injury, using the two electronic systems. These patients met the inclusion criteria and were assessed for their impaired balance at the District of Columbia Veterans Affair Medical Center, Washington, DC, USA., Results: There were six static balance tests conducted on either NeuroCom or BioSensics system in triplicate. Of the data for 36 sets of statistical data analyses, there were significant correlations among those for eight data sets (22.2%) between the two systems. The strongest positive correlation between the data from the two systems was found during the baseline test, when inputs from visual, vestibular and sensorymotor sources were uninterrupted. The data from the remaining experimental conditions did not correlate significantly with one another., Conclusions: Both NeuroCom and BioSensics provided comparable data in eight out of 36 experimental conditions in the assessment of static balance in patients with mild traumatic brain injury. The findings clarified the ambiguities in the application of NeuroCom versus BioSensics, provided new knowledge for the field of physical medicine and rehabilitation, and improved the clinical assessment of static balance in patients with mTBI.

Objectives: The Automated Neuropsychological Assessment Metrics 4 TBI-MIL (ANAM4) is a computerized cognitive test often used in post-concussion assessments with U.S. service members (SMs). However, existing evidence remains mixed regarding ANAM4's ability to identify cognitive issues following mild traumatic brain injury (mTBI). Studies typically examine ANAM4 using standardized scores and/ or comparisons to a baseline. A more fine-grained approach involves examining inconsistency within an individual's performance (i.e., intraindividual variability)., Methods: Data from 237 healthy control SMs and 105 SMs within seven days of mTBI who took the ANAM4 were included in analyses. Using each individual's raw scores on a simple reaction time (RT) subtest (SRT1) that is repeated at the end of the battery (SRT2), we calculated mean raw RT and the intraindividual standard deviation (ISD) of trial-by-trial RT. Analyses investigated differences between groups in mean RT, RT variability (i.e., ISD), and change in ISD from SRT1 and SRT2., Results: Using regression residuals to control for demographic variables, analysis of variance, and pairwise comparisons revealed the control group had faster mean RT and smaller ISD compared to the mTBI group. Furthermore, the mTBI group had a significant increase in ISD from SRT1 to SRT2, with effect sizes exceeding the minimum practical effect for comparisons of ISD in SRT2 and change in ISD from SRT1 to SRT2., Conclusions: While inconsistencies in performance are often viewed as test error, the results suggest intraindividual cognitive variability may be more sensitive than traditional metrics in detecting changes in cognitive function after mTBI. Additionally, the findings highlight the utility of the ANAM4's repeating a RT subtest at two points in the same session for exploring within-subject differences in performance variability. (JINS, 2018, 24, 156-162).

Objective: The study was designed to replicate and extend pervious findings demonstrating the high rates of invalid neuropsychological testing in military service members (SMs) with a history of mild traumatic brain injury (mTBI) assessed in the context of a medical evaluation board (MEB)., Method: Two hundred thirty-one active duty SMs (61 of which were undergoing an MEB) underwent neuropsychological assessment. Performance validity (Word Memory Test) and symptom validity (MMPI-2-RF) test data were compared across those evaluated within disability (MEB) and clinical contexts., Results: As with previous studies, there were significantly more individuals in an MEB context that failed performance (MEB = 57%, non-MEB = 31%) and symptom validity testing (MEB = 57%, non-MEB = 22%) and performance validity testing had a notable affect on cognitive test scores. Performance and symptom validity test failure rates did not vary as a function of the reason for disability evaluation when divided into behavioral versus physical health conditions., Conclusions: These data are consistent with past studies, and extends those studies by including symptom validity testing and investigating the effect of reason for MEB. This and previous studies demonstrate that more than 50% of SMs seen in the context of an MEB will fail performance validity tests and over-report on symptom validity measures. These results emphasize the importance of using both performance and symptom validity testing when evaluating SMs with a history of mTBI, especially if they are being seen for disability evaluations, in order to ensure the accuracy of cognitive and psychological test data., (Published by Oxford University Press 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Objective The cognitive profile of any neurological disorder is very important throughout the duration of a person's treatment. It has a role in diagnosis, prognosis, and even after remission of active symptoms. It is a common trend among clinicians to monitor and compare the cognitive profiles of different disease conditions to locate the area of maximum dysfunction, with respect to a particular diagnosis. This study correlates the cognitive profiles of mild traumatic brain injury (mTBI) and mild vascular cognitive impairment (mVCI). Materials and Methods The study population comprised 30 mTBI and 30 mVCI patients medically diagnosed by a neurologist. The patients were been selected from the neuromedical outpatient department (OPD) and neurosurgery OPD of the Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Trivandrum. Simple random sampling had been used to select the sample. The patients diagnosed with the stated disease conditions were referred for neuropsychological assessment. Testable and cooperative patients were recruited for the study. To stabilize the data and for a transparent comparison, 30 healthy controls with no medically diagnosed illnesses were also added to the study. The results were analyzed using R. Results and Conclusion The study concluded that cognitive profiles of mTBI and mVCI patients were significantly different from the cognitive profiles of healthy controls, but there was no statistically significant difference between the cognitive profiles of mVCI and mTBI patients except in confrontation naming and recognition memory. [ABSTRACT FROM AUTHOR]

Identifying factors that moderate cognitive outcomes following mild traumatic brain injury (mTBI) is crucial. Prospective memory (PM) is a cognitive domain of interest in mTBI recovery as it may be especially sensitive to TBI-related changes. Since studies show that genetic status – particularly possession of the apolipoprotein E (APOE) ε4 allele – can modify PM performance, we investigated associations between mTBI status and APOE-ε4 genotype on PM performance in a well-characterized sample of Veterans with neurotrauma histories. 59 Veterans (mTBI = 33, Military Controls [MCs] = 26; age range: 24–50; average years post-injury = 10.41) underwent a structured clinical interview, neuropsychological assessment, and genotyping. The Memory for Intentions Test (MIST) measured PM across multiple subscales. ANCOVAs, adjusting for age and posttraumatic stress symptoms, tested the effects of mTBI status (mTBI vs. MC) and ε4 status (ε4+ vs. ε4−) on MIST scores. Veterans with mTBI history performed more poorly compared to MCs on the MIST 15-min delay (p=.002, ηp2 =.160), Time Cue (p =.003, ηp2 =.157), and PM Total (p =.016, ηp2 =.102). Those with at least one copy of the ε4 allele performed more poorly compared to ε4- Veterans on the MIST 15-min delay (p =.011, ηp2 =.113) and PM Total (p =.048, ηp2 =.071). No significant interactions were observed between mTBI and APOE-ε4 status on MIST outcomes (ps>.25). Within the mTBI group, APOE-ε4+ Veterans performed worse than APOE-ε4− Veterans on the MIST 15-min delay subscale (p =.031, ηp2 =.150). mTBI history and APOE-ε4 genotype status were independently associated with worse PM performance compared to those without head injury histories or possession of the APOE-e4 genotype. Performance on the MIST 15-min delay was worse in Veterans with both risk factors (mTBI history and APOE-ε4 positivity). Findings suggest that genetic status may modify outcomes even in relatively young Veterans with mTBI histories. Future research examining longitudinal associations and links to neuroimaging and biomarker data are needed. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to evaluate the reliability and validity of three computerized neurocognitive assessment tools (CNTs; i.e., ANAM, DANA, and ImPACT) for assessing mild traumatic brain injury (mTBI) in patients recruited through a level I trauma center emergency department (ED)., Methods: mTBI (n=94) and matched trauma control (n=80) subjects recruited from a level I trauma center emergency department completed symptom and neurocognitive assessments within 72 hr of injury and at 15 and 45 days post-injury. Concussion symptoms were also assessed via phone at 8 days post-injury., Results: CNTs did not differentiate between groups at any time point (e.g., M 72-hr Cohen's d=-.16, .02, and .00 for ANAM, DANA, and ImPACT, respectively; negative values reflect greater impairment in the mTBI group). Roughly a quarter of stability coefficients were over .70 across measures and test-retest intervals in controls. In contrast, concussion symptom score differentiated mTBI vs. control groups acutely), with this effect size diminished over time (72-hr and day 8, 15, and 45 Cohen's d=-.78, -.60, -.49, and -.35, respectively)., Conclusions: The CNTs evaluated, developed and widely used to assess sport-related concussion, did not yield significant differences between patients with mTBI versus other injuries. Symptom scores better differentiated groups than CNTs, with effect sizes weaker than those reported in sport-related concussion studies. Nonspecific injury factors, and other characteristics common in ED settings, likely affect CNT performance across trauma patients as a whole and thereby diminish the validity of CNTs for assessing mTBI in this patient population. (JINS, 2017, 23, 293-303).

This study evaluated the clinical utility of two embedded performance validity tests (PVTs) developed for the Repeatable Battery for the Assessment of Neuropsychological Status: the Effort Index (EI) and the Effort Scale (ES) in mild traumatic brain injury (TBI) patients. Participants were 250 military service members (94.0% male; Age: M = 28.4, SD = 7.6) evaluated following mild TBI on average 7.4 months (SD = 15.6) post-injury. Participants were divided into two groups based on their performance on the Test of Memory Malingering: PVT-Pass, n = 193; PVT-Fail, n = 57. For the EI, recommended cut-offs for extremely probable, highly probable, and probable poor effort were established. A cut-off score of >3 resulted in low sensitivity (.14), high specificity (.99) and positive predictive power (.94), and moderate negative predictive power (.68) and is recommended for identifying highly probable poor effort. For both the EI and ES, cut-offs for probable poor effort were identified; however, classification accuracy was not much improved relative to simply using the sum of the List Recognition and Digit Span raw scores to classify poor effort. It is acknowledged that the use of a different criterion would likely have resulted in different findings. Nevertheless, findings support the use of the EI and the ES as a "red flag" for possible poor effort in mild TBI patients, but suggest that, in most cases, additional PVTs would be required to accurately rule poor effort in or out.

Background: Mild traumatic brain injury (mTBI) is common in children. Long-term cognitive and behavioral outcomes as well as underlying structural brain alterations following pediatric mTBI have yet to be determined. In addition, the effect of age-at-injury on long-term outcomes is largely unknown. Methods: Children with a history of mTBI (n = 406; M age = 10 years, SD age = 0.63 years) who participated in the Adolescent Brain Cognitive Development (ABCD) study were matched (1:2 ratio) with typically developing children (TDC; n = 812) and orthopedic injury (OI) controls (n = 812). Task-based executive functioning, parent-rated executive functioning and emotion-regulation, and self-reported impulsivity were assessed cross-sectionally. Regression models were used to examine the effect of mTBI on these domains. The effect of age-at-injury was assessed by comparing children with their first mTBI at either 0-3, 4-7, or 8-10 years to the respective matched TDC controls. Fractional anisotropy (FA) and mean diffusivity (MD), both MRI-based measures of white matter microstructure, were compared between children with mTBI and controls. Results: Children with a history of mTBI displayed higher parent-rated executive dysfunction, higher impulsivity, and poorer self-regulation compared to both control groups. At closer investigation, these differences to TDC were only present in one respective age-at-injury group. No alterations were found in task-based executive functioning or white matter microstructure. Conclusions: Findings suggest that everyday executive function, impulsivity, and emotion-regulation are affected years after pediatric mTBI. Outcomes were specific to the age at which the injury occurred, suggesting that functioning is differently affected by pediatric mTBI during vulnerable periods. Groups did not differ in white matter microstructure. [ABSTRACT FROM AUTHOR]

The BrainScope Ahead 300 is designed for use by health care professionals to aid in the assessment of patients suspected of a mild traumatic brain injury. The purpose of the current study was to establish normative data for the cognitive test component of the Ahead 300 system and to evaluate the role of demographic factors on test performance. Healthy, community-dwelling adults between the ages of 18 and 80 recruited from five geographically distributed sites were administered Android versions of the ANAM Matching to Sample and Procedural Reaction Time tests that comprise the cognitive test component of the Ahead 300 system by trained personnel. Scores were correlated with age, education, and race. Age accounted for the majority of the variance in test scores with additional significant, but minor, contributions of education and race. Gender did not account for a significant proportion of the variance for either test. Based on these results, the normative data for 551 individuals are presented stratified by age. These are the first available normative data for these tests when administered using the Ahead 300 system and will assist health care professionals in determining the degree to which scores on the cognitive tests reflect impaired performance.

Patients subjected to severe acceleration forces in motor vehicle accidents that met criteria for uncomplicated mild traumatic brain injury (mTBI) in the absence of direct impact to the head were examined neuropsychologically using the Halstead-Reitan Neuropsychological Test Battery. The subjects were litigants and/or insurance claimants for whom there was psychometric evidence of acceptable test effort. The purpose of the study was to provide descriptive neuropsychological data for this particular clinical population. Individual test results were interpreted using inferential methods of level of performance, pathognomonic signs, score patterns, and right-left performance differences. These interpretive strategies yielded group data from which frequencies and percentages of atypical neuropsychological characteristics were calculated. The most salient clinical characteristics involved atypical right-left performance relationships on simple and more complex tests of motor function. Clinical data provided support for the possibility that a minority of nonimpact litigants or insurance claimants that sustain uncomplicated mTBI experience persistent diminishment in some neuropsychological abilities.

Cognitive impairments are often experienced after a mild traumatic brain injury (mTBI). In the clinical arena, neuropsychological assessments are used frequently to detect cognitive deficits. Animal models of mTBI, however, rely on an assortment of behavioral tasks to assess cognitive outcome. Computer-based touchscreen systems have been developed for rodents and are hypothesized to offer a translational approach to evaluate cognitive function because of the similarities of tasks performed in rodents to those implemented in humans. While these touchscreen systems have been used in pre-clinical models of neurodegenerative diseases and psychiatric disorders, their use in assessing cognitive impairment after mTBI has not been investigated. We hypothesized that mTBI would result in impaired cognitive performance on touchscreen tasks, particularly those with hippocampal-based learning components, including the paired associate learning (PAL) task and the location discrimination (LD) task. Adult male, C57BL/6 mice received a single impact-acceleration mTBI. We found that training mice before injury to perform to criteria is arduous and that performance is sensitive to many environmental variables. Despite extensive optimization and training, mice failed to perform better than chance in the PAL paradigm. Alternatively, mice demonstrated some capacity to learn in the LD paradigm, but only with the easier stages of the task. The mTBI did not affect performance in the LD paradigm, however. Thus, we concluded that under the conditions presented here, the PAL and LD touchscreen tasks are not robust outcome measures for the evaluation of cognitive performance in C57BL/6 mice after a single impact-acceleration mTBI.

Introduction: Paediatric mild traumatic brain injury (mTBI) is a public health burden. Clinicians urgently need evidence-based guidance to manage mTBI, but gold standards for diagnosing and predicting the outcomes of mTBI are lacking. The objective of the Advancing Concussion Assessment in Pediatrics (A-CAP) study is to assess a broad pool of neurobiological and psychosocial markers to examine associations with postinjury outcomes in a large sample of children with either mTBI or orthopaedic injury (OI), with the goal of improving the diagnosis and prognostication of outcomes of paediatric mTBI., Methods and Analysis: A-CAP is a prospective, longitudinal cohort study of children aged 8.00-16.99 years with either mTBI or OI, recruited during acute emergency department (ED) visits at five sites from the Pediatric Emergency Research Canada network. Injury information is collected in the ED; follow-up assessments at 10 days and 3 and 6 months postinjury measure a variety of neurobiological and psychosocial markers, covariates/confounders and outcomes. Weekly postconcussive symptom ratings are obtained electronically. Recruitment began in September 2016 and will occur for approximately 24 months. Analyses will test the major hypotheses that neurobiological and psychosocial markers can: (1) differentiate mTBI from OI and (2) predict outcomes of mTBI. Models initially will focus within domains (eg, genes, imaging biomarkers, psychosocial markers), followed by multivariable modelling across domains. The planned sample size (700 mTBI, 300 OI) provides adequate statistical power and allows for internal cross-validation of some analyses., Ethics and Dissemination: The ethics boards at all participating institutions have approved the study and all participants and their parents will provide informed consent or assent. Dissemination will follow an integrated knowledge translation plan, with study findings presented at scientific conferences and in multiple manuscripts in peer-reviewed journals., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)