Relationship Between Neighborhood Disadvantage and Mild Traumatic Brain Injury Symptoms.

OBJECTIVE: To test the hypotheses that (1) higher neighborhood disadvantage is associated with greater injury-related symptom severity in civilians with mild traumatic brain injury (mTBI) and (2) neighborhood disadvantage remains predictive after controlling for other established predictors. SETTING: Level 1 trauma center and affiliated academic medical center. PARTICIPANTS: N = 171 individuals with mTBI. DESIGN: Prospective cohort study. MAIN MEASURES: Rivermead Post Concussion Symptoms Questionnaire (RPQ) total score assessed less than 24 hours and at 2 weeks, 3 months, and 6 months postinjury. Linear mixed-effects models were used to assess the relationship between predictor variables and mTBI-related symptom burden (RPQ score). Neighborhood disadvantage was quantified by the Area Deprivation Index (ADI), a composite of 17 markers of socioeconomic position (SEP) scored at the census block group level. RESULTS: Individuals in the upper ADI quartile of the national distribution displayed higher RPQ symptoms than those in the lower 3 quartiles ( P < .001), with a nonsignificant ADI × visit interaction ( P = .903). In a multivariable model, the effect of ADI remained significant ( P = .034) after adjusting for demographics, individual SEP, and injury factors. Other unique predictors in the multivariable model were gender (gender × visit P = .035), health insurance type ( P = .017), and injury-related litigation ( P = .012). CONCLUSION: Neighborhood disadvantage as quantified by the ADI is robustly associated with greater mTBI-related symptom burden throughout the first 6 months postinjury. That the effect of ADI remained after controlling for demographics, individual SEP, and injury characteristics implies that neighborhood disadvantage is an important, understudied factor contributing to clinical recovery from mTBI.

Feasibility and Utility of a Flexible Outcome Assessment Battery for Longitudinal Traumatic Brain Injury Research: A TRACK-TBI Study.

The effects of traumatic brain injury (TBI) are difficult to measure in longitudinal cohort studies, because disparate pre-injury characteristics and injury mechanisms produce variable impairment profiles and recovery trajectories. In preparation for the Transforming Research and Clinical Knowledge in TBI (TRACK-TBI) study, which followed patients with injuries ranging from uncomplicated mild TBI to coma, we designed a multi-dimensional Flexible outcome Assessment Battery (FAB). The FAB relies on a decision-making algorithm that assigns participants to a Comprehensive (CAB) or Abbreviated Assessment Battery (AAB) and guides test selection across all phases of recovery. To assess feasibility of the FAB, we calculated the proportion of participants followed at 2 weeks (2w) and at 3, 6, and 12 months (3m, 6m, 12m) post-injury who completed the FAB and received valid scores. We evaluated utility of the FAB by examining differences in 6m and 12m Glasgow Outcome Scale-Extended (GOSE) scores between participant subgroups derived from the FAB-enabled versus traditional approach to outcome assessment applied at 2w. Among participants followed at 2w (n = 2094), 3m (n = 1871), 6m (n = 1736), and 12m (n = 1607) post-injury, 95-99% received valid completion scores on the FAB, in full or in part, either in person or by telephone. Level of function assessed by the FAB-enabled approach at 2w was associated with 6m and 12m GOSE scores (proportional odds p < 0.001). These findings suggest that the participant classification methodology afforded by the FAB may enable more effective data collection to improve detection of natural history changes and TBI treatment effects.

Linking Rivermead Post Concussion Symptoms Questionnaire (RPQ) and Sport Concussion Assessment Tool (SCAT) scores with item response theory.

OBJECTIVE: Despite the public health burden of traumatic brain injury (TBI) across broader society, most TBI studies have been isolated to a distinct subpopulation. The TBI research literature is fragmented further because often studies of distinct populations have used different assessment procedures and instruments. Addressing calls to harmonize the literature will require tools to link data collected from different instruments that measure the same construct, such as civilian mild traumatic brain injury (mTBI) and sports concussion symptom inventories. METHOD: We used item response theory (IRT) to link scores from the Rivermead Post Concussion Symptoms Questionnaire (RPQ) and the Sport Concussion Assessment Tool (SCAT) symptom checklist, widely used instruments for assessing civilian and sport-related mTBI symptoms, respectively. The sample included data from n = 397 patients who suffered a sports-related concussion, civilian mTBI, orthopedic injury control, or non-athlete control and completed the SCAT and/or RPQ. RESULTS: The results of several analyses supported sufficient unidimensionality to treat the RPQ + SCAT combined item set as measuring a single construct. Fixed-parameter IRT was used to create a cross-walk table that maps RPQ total scores to SCAT symptom severity scores. Linked and observed scores were highly correlated (r = .92). Standard errors of the IRT scores were slightly higher for civilian mTBI patients and orthopedic controls, particularly for RPQ scores linked from the SCAT. CONCLUSION: By linking the RPQ to the SCAT we facilitated efforts to effectively combine samples and harmonize data relating to mTBI.

Assessment of Blood Biomarker Profile After Acute Concussion During Combative Training Among US Military Cadets: A Prospective Study From the NCAA and US Department of Defense CARE Consortium.

Importance: Validation of protein biomarkers for concussion diagnosis and management in military combative training is important, as these injuries occur outside of traditional health care settings and are generally difficult to diagnose. Objective: To investigate acute blood protein levels in military cadets after combative training-associated concussions. Design, Setting, and Participants: This multicenter prospective case-control study was part of a larger cohort study conducted by the National Collegiate Athletic Association and the US Department of Defense Concussion Assessment Research and Education (CARE) Consortium from February 20, 2015, to May 31, 2018. The study was performed among cadets from 2 CARE Consortium Advanced Research Core sites: the US Military Academy at West Point and the US Air Force Academy. Cadets who incurred concussions during combative training (concussion group) were compared with cadets who participated in the same combative training exercises but did not incur concussions (contact-control group). Clinical measures and blood sample collection occurred at baseline, the acute postinjury point (<6 hours), the 24- to 48-hour postinjury point, the asymptomatic postinjury point (defined as the point at which the cadet reported being asymptomatic and began the return-to-activity protocol), and 7 days after return to activity. Biomarker levels and estimated mean differences in biomarker levels were natural log (ln) transformed to decrease the skewness of their distributions. Data were collected from August 1, 2016, to May 31, 2018, and analyses were conducted from March 1, 2019, to January 14, 2020. Exposure: Concussion incurred during combative training. Main Outcomes and Measures: Proteins examined included glial fibrillary acidic protein, ubiquitin C-terminal hydrolase-L1, neurofilament light chain, and tau. Quantification was conducted using a multiplex assay (Simoa; Quanterix Corp). Clinical measures included the Sport Concussion Assessment Tool-Third Edition symptom severity evaluation, the Standardized Assessment of Concussion, the Balance Error Scoring System, and the 18-item Brief Symptom Inventory. Results: Among 103 military service academy cadets, 67 cadets incurred concussions during combative training, and 36 matched cadets who engaged in the same training exercises did not incur concussions. The mean (SD) age of cadets in the concussion group was 18.6 (1.3) years, and 40 cadets (59.7%) were male. The mean (SD) age of matched cadets in the contact-control group was 19.5 (1.3) years, and 25 cadets (69.4%) were male. Compared with cadets in the contact-control group, those in the concussion group had significant increases in glial fibrillary acidic protein (mean difference in ln values, 0.34; 95% CI, 0.18-0.50; P < .001) and ubiquitin C-terminal hydrolase-L1 (mean difference in ln values, 0.97; 95% CI, 0.44-1.50; P < .001) levels at the acute postinjury point. The glial fibrillary acidic protein level remained high in the concussion group compared with the contact-control group at the 24- to 48-hour postinjury point (mean difference in ln values, 0.22; 95% CI, 0.06-0.38; P = .007) and the asymptomatic postinjury point (mean difference in ln values, 0.21; 95% CI, 0.05-0.36; P = .01). The area under the curve for all biomarkers combined, which was used to differentiate cadets in the concussion and contact-control groups, was 0.80 (95% CI, 0.68-0.93; P < .001) at the acute postinjury point. Conclusions and Relevance: This study's findings indicate that blood biomarkers have potential for use as research tools to better understand the pathobiological changes associated with concussion and to assist with injury identification and recovery from combative training-associated concussions among military service academy cadets. These results extend the previous findings of studies of collegiate athletes with sport-associated concussions.

Plasma Biomarker Concentrations Associated With Return to Sport Following Sport-Related Concussion in Collegiate Athletes-A Concussion Assessment, Research, and Education (CARE) Consortium Study.

Importance: Identifying plasma biomarkers associated with the amount of time an athlete may need before they return to sport (RTS) following a sport-related concussion (SRC) is important because it may help to improve the health and safety of athletes. Objective: To examine whether plasma biomarkers can differentiate collegiate athletes who RTS in less than 14 days or 14 days or more following SRC. Design, Setting, and Participants: This multicenter prospective diagnostic study, conducted by the National Collegiate Athletics Association-Department of Defense Concussion Assessment, Research, and Education Consortium, included 127 male and female athletes who had sustained an SRC while enrolled at 6 Concussion Assessment, Research, and Education Consortium Advanced Research Core sites as well as 2 partial-Advanced Research Core military service academies. Data were collected between February 2015 and May 2018. Athletes with SRC completed clinical testing and blood collection at preseason (baseline), postinjury (0-21 hours), 24 to 48 hours postinjury, time of symptom resolution, and 7 days after unrestricted RTS. Main Outcomes and Measures: A total of 3 plasma biomarkers (ie, total tau protein, glial fibrillary acidic protein [GFAP], and neurofilament light chain protein [Nf-L]) were measured using an ultrasensitive single molecule array technology and were included in the final analysis. RTS was examined between athletes who took less than 14 days vs those who took 14 days or more to RTS following SRC. Linear mixed models were used to identify significant interactions between period by RTS group. Area under the receiver operating characteristic curve analyses were conducted to examine whether these plasma biomarkers could discriminate between RTS groups. Results: The 127 participants had a mean (SD) age of 18.9 (1.3) years, and 97 (76.4%) were men; 65 (51.2%) took less than 14 days to RTS, and 62 (48.8%) took 14 days or more to RTS. Linear mixed models identified significant associations for both mean (SE) plasma total tau (24-48 hours postinjury, <14 days RTS vs ≥14 days RTS: -0.65 [0.12] pg/mL vs -0.14 [0.14] pg/mL; P = .008) and GFAP (postinjury, 14 days RTS vs ≥14 days RTS: 4.72 [0.12] pg/mL vs 4.39 [0.11] pg/mL; P = .04). Total tau at the time of symptom resolution had acceptable discrimination power (area under the receiver operating characteristic curve, 0.75; 95% CI, 0.63-0.86; P < .001). We also examined a combined plasma biomarker panel that incorporated Nf-L, GFAP, and total tau at each period to discriminate RTS groups. Although the analyses did reach significance at each time period when combined, results indicated that they were poor at distinguishing the groups (area under the receiver operating characteristic curve, <0.7). Conclusions and Relevance: The findings of this study suggest that measures of total tau and GFAP may identify athletes who will require more time to RTS. However, further research is needed to improve our ability to determine recovery following an SRC.

Bifactor Model of the Sport Concussion Assessment Tool Symptom Checklist: Replication and Invariance Across Time in the CARE Consortium Sample.

BACKGROUND: Identifying separate dimensions of concussion symptoms may inform a precision medicine approach to treatment. It was previously reported that a bifactor model identified distinct acute postconcussion symptom dimensions. PURPOSE: To replicate previous findings of a bifactor structure of concussion symptoms in the Concussion Assessment Research and Education (CARE) Consortium sample, examine measurement invariance from pre- to postinjury, and evaluate whether factors are associated with other clinical and biomarker measures. STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 2. METHODS: Collegiate athletes were prospectively evaluated using the Sport Concussion Assessment Tool-3 (SCAT-3) during preseason (N = 31,557); 2789 were followed at <6 hours and 24 to 48 hours after concussion. Item-level SCAT-3 ratings were analyzed using exploratory and confirmatory factor analyses. Bifactor and higher-order models were compared for their fit and interpretability. Measurement invariance tested the stability of the identified factor structure across time. The association between factors and criterion measures (clinical and blood-based markers of concussion severity, symptom duration) was evaluated. RESULTS: The optimal structure for each time point was a 7-factor bifactor model: a General factor, on which all items loaded, and 6 specific factors-Vestibulo-ocular, Headache, Sensory, Fatigue, Cognitive, and Emotional. The model manifested strict invariance across the 2 postinjury time points but only configural invariance from baseline to postinjury. From <6 to 24-48 hours, some dimensions increased in severity (Sensory, Fatigue, Emotional), while others decreased (General, Headache, Vestibulo-ocular). The factors correlated with differing clinical and biomarker criterion measures and showed differing patterns of association with symptom duration at different time points. CONCLUSION: Bifactor modeling supported the predominant unidimensionality of concussion symptoms while revealing multidimensional properties, including a large dominant General factor and 6 independent factors: Headache, Vestibulo-ocular, Sensory, Cognitive, Fatigue, and Emotional. Unlike the widely used SCAT-3 symptom severity score, which declines gradually after injury, the bifactor model revealed separable symptom dimensions that have distinct trajectories in the acute postinjury period and different patterns of association with other markers of injury severity and outcome. CLINICAL RELEVANCE: The SCAT-3 total score remains a valuable, robust index of overall concussion symptom severity, and the specific factors identified may inform management strategies. Because some symptom dimensions continue to worsen in the first 24 to 48 hours after injury (ie, Sensory, Fatigue, Emotional), routine follow-up in this time frame may be valuable to ensure that symptoms are managed effectively.

Prospective Assessment of Acute Blood Markers of Brain Injury in Sport-Related Concussion.

There is a pressing need to identify objective biomarkers for the assessment of sport-related concussion (SRC) to reduce the reliance on clinical judgment for the management of these injuries. The goal of the current study was to prospectively establish the acute effects of SRC on serum levels of S100 calcium-binding protein beta (S100B), glial fibrillary acidic protein (GFAP), and ubiquitin C-terminal hydrolase-L1 (UCH-L1). Collegiate and high school football players were enrolled and provided blood at pre-season. Injured athletes participated in follow-up visits at ∼6 and 24-48 h following documented SRC (n = 32). Uninjured football players participated in similar follow-up visits and served as controls (n = 29). The median time between injury and blood collection was 2 h (6 h visit) and 22.5 h (24-48 h visit) in concussed athletes. Concussed athletes had significantly elevated UCH-L1 levels at the 6 h visit relative to pre-season levels (Z = 2.22, p = 0.03) and levels in control athletes (Z = 3.02, p = 0.003). Concussed athletes also had elevated S100B at 6 h relative to pre-season (Z = 2.07, p = 0.04) and controls (Z = 2.75, p = 0.006). Both markers showed fair discrimination between concussed and control athletes (UCH-L1 area under receiver operating characteristic curve [AUC] [95% CI] = 0.74 [0.61-0.88], S100B AUC = 0.72 [0.58-0.87]). Percent-change of UCH-L1 and S100B at 6 h relative to pre-season also showed fair discrimination (AUC = 0.79 [0.66-0.92] and AUC = 0.77 [0.64-0.90]). GFAP levels did not differ between groups or in concussed athletes relative to pre-season. This study provides prospective evidence of significant increases in serum levels of UCH-L1 and S100B during the early acute period following SRC, and lays the foundation for future studies examining the clinical potential for blood-based biomarkers in the early detection of concussion.

Validating Multidimensional Outcome Assessment Using the TBI Common Data Elements: An Analysis of the TRACK-TBI Pilot Sample.

The Glasgow Outcome Scale-Extended (GOSE) is often the primary outcome measure in clinical trials for traumatic brain injury (TBI). Although the GOSE's capture of global function outcome has several strengths, concerns have been raised about its limited ability to identify mild disability and failure to capture the full scope of problems patients exhibit after TBI. This analysis examined the convergence of disability ratings across a multidimensional set of outcome domains in the Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI) Pilot study. The study collected measures recommended by the TBI Common Data Elements (CDE) Workgroup. Patients presenting to 3 emergency departments with a TBI of any severity enrolled in TRACK-TBI prospectively after injury; outcome measures were collected at 3 and six months postinjury. Analyses examined frequency of impairment and overlap between impairment status across the CDE outcome domains of Global Level of Functioning (GOSE), Neuropsychological (cognitive) Impairment, Psychological Status, TBI Symptoms, and Quality of Life. GOSE score correlated in the expected direction with other outcomes (M Spearman's rho = .21 and .49 with neurocognitive and self-report outcomes, respectively). The subsample in the Upper Good Recovery (GOSE 8) category appeared quite healthy across most other outcomes, although 19.0% had impaired executive functioning (Trail Making Test Part B). A significant minority of participants in the Lower Good Recovery subgroup (GOSE 7) met criteria for impairment across numerous other outcome measures. The findings highlight the multidimensional nature of TBI recovery and the limitations of applying only a single outcome measure.

Prospective, Head-to-Head Study of Three Computerized Neurocognitive Assessment Tools Part 2: Utility for Assessment of Mild Traumatic Brain Injury in Emergency Department Patients.

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).

Baseline Performance and Psychometric Properties of the Child Sport Concussion Assessment Tool 3 (Child-SCAT3) in 5- to 13-year-old Athletes.

OBJECTIVE: To determine the normative, baseline performance and psychometric properties of the Child Sport Concussion Assessment Tool 3 (Child-SCAT3) in 5- to 13-year-old athletes. DESIGN: Cross-sectional study. SETTING: Practice fields. PARTICIPANTS: Contact sport athletes (N = 155) 5 to 13 years old. INDEPENDENT VARIABLES: Age, gender, verbal intellectual functioning (receptive vocabulary). MAIN OUTCOME MEASURES: Child-SCAT3: self-reported and parent-reported symptoms, cognitive performance (child form of the Standardized Assessment of Concussion; SAC-C), and balance (modified Balance Error Scoring System, mBESS-C; tandem gait). A subset of the sample repeated the Child-SCAT3 at another date. Some subjects also completed the Adult-SCAT3 version of the symptom checklist and mBESS. RESULTS: Small-to-medium-sized effects of age were observed on all Child-SCAT3 components. Effects of gender and receptive vocabulary were observed on select components of the SCAT3. Younger age and lower receptive vocabulary were independently associated with greater symptom endorsement, yet parents rated higher symptom burden for older children. Internal consistency reliability and stability of symptom ratings was good to excellent. Stability was more modest for SAC-C and tandem gait scores and very poor for mBESS-C scores, perhaps due to restricted variance. Inter-rater reliability (self-rated vs parent-rated symptoms) was fair. CONCLUSIONS: The Child-SCAT3 self-report symptom checklist may be inappropriate to administer to younger school-aged children. Some of the age effects observed warrant use of demographically appropriate norms in Child-SCAT3 interpretation. The findings can provide guidance for clinicians assessing children of varying ages and point to directions for further development of refined approaches for pediatric concussion assessment.

Reliability and Validity of the Sport Concussion Assessment Tool-3 (SCAT3) in High School and Collegiate Athletes.

BACKGROUND: The Sport Concussion Assessment Tool-3 (SCAT3) facilitates sideline clinical assessments of concussed athletes. Yet, there is little published research on clinically relevant metrics for the SCAT3 as a whole. PURPOSE: We documented the psychometric properties of the major SCAT3 components (symptoms, cognition, balance) and derived clinical decision criteria (ie, reliable change score cutoffs and normative conversation tables) for clinicians to apply to cases with and without available preinjury baseline data. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: High school and collegiate athletes (N = 2018) completed preseason baseline evaluations including the SCAT3. Re-evaluations of 166 injured athletes and 164 noninjured controls were performed within 24 hours of injury and at 8, 15, and 45 days after injury. Analyses focused on predictors of baseline performance, test-retest reliability, and sensitivity and specificity of the SCAT3 using either single postinjury cutoffs or reliable change index (RCI) criteria derived from this sample. RESULTS: Athlete sex, level of competition, attention-deficit/hyperactivity disorder (ADHD), learning disability (LD), and estimated verbal intellectual ability (but not concussion history) were associated with baseline scores on ≥1 SCAT3 components (small to moderate effect sizes). Female sex, high school level of competition (vs college), and ADHD were associated with higher baseline symptom ratings (d = 0.25-0.32). Male sex, ADHD, and LD were associated with lower baseline Standardized Assessment of Concussion (SAC) scores (d = 0.28-0.68). Male sex, high school level of competition, ADHD, and LD were associated with poorer baseline Balance Error Scoring System (BESS) performance (d = 0.14-0.26). After injury, the symptom checklist manifested the largest effect size at the 24-hour assessment (d = 1.52), with group differences diminished but statistically significant at day 8 (d = 0.39) and nonsignificant at day 15. Effect sizes for the SAC and BESS were small to moderate at 24 hours (SAC: d = -0.36; modified BESS: d = 0.46; full BESS: d = 0.51) and became nonsignificant at day 8 (SAC) and day 15 (BESS). Receiver operating characteristic curve analyses demonstrated a stronger discrimination for symptoms (area under the curve [AUC] = 0.86) than cognitive and balance measures (AUCs = 0.58 and 0.62, respectively), with comparable discrimination of each SCAT3 component using postinjury scores alone versus baseline-adjusted scores (P = .71-.90). Normative conversion tables and RCI criteria were created to facilitate the use of the SCAT3 both with and without baseline test results. CONCLUSION: Individual predictors should be taken into account when interpreting the SCAT3. The normative conversion tables and RCIs presented can be used to help interpret concussed athletes' performance both with and without baseline data, given the comparability of the 2 interpretative approaches.

Prospective, Head-to-Head Study of Three Computerized Neurocognitive Assessment Tools (CNTs): Reliability and Validity for the Assessment of Sport-Related Concussion.

Limited data exist comparing the performance of computerized neurocognitive tests (CNTs) for assessing sport-related concussion. We evaluated the reliability and validity of three CNTs-ANAM, Axon Sports/Cogstate Sport, and ImPACT-in a common sample. High school and collegiate athletes completed two CNTs each at baseline. Concussed (n=165) and matched non-injured control (n=166) subjects repeated testing within 24 hr and at 8, 15, and 45 days post-injury. Roughly a quarter of each CNT's indices had stability coefficients (M=198 day interval) over .70. Group differences in performance were mostly moderate to large at 24 hr and small by day 8. The sensitivity of reliable change indices (RCIs) was best at 24 hr (67.8%, 60.3%, and 47.6% with one or more significant RCIs for ImPACT, Axon, and ANAM, respectively) but diminished to near the false positive rates thereafter. Across time, the CNTs' sensitivities were highest in those athletes who became asymptomatic within 1 day before neurocognitive testing but was similar to the tests' false positive rates when including athletes who became asymptomatic several days earlier. Test-retest reliability was similar among these three CNTs and below optimal standards for clinical use on many subtests. Analyses of group effect sizes, discrimination, and sensitivity and specificity suggested that the CNTs may add incrementally (beyond symptom scores) to the identification of clinical impairment within 24 hr of injury or within a short time period after symptom resolution but do not add significant value over symptom assessment later. The rapid clinical recovery course from concussion and modest stability probably jointly contribute to limited signal detection capabilities of neurocognitive tests outside a brief post-injury window. (JINS, 2016, 22, 24-37).

False-Positive Rates of Reliable Change Indices for Concussion Test Batteries: A Monte Carlo Simulation.

BACKGROUND: Neurocognitive testing is widely performed for the assessment of concussion. Athletic trainers can use preseason baselines with reliable change indices (RCIs) to ascertain whether concussed athletes' cognitive abilities are below preinjury levels. Although the percentage of healthy individuals who show decline on any individual test is determined by its RCI's confidence level (eg, 10% false-positive rate using an RCI with an 80% confidence interval), the expected rate of 1 or more significant RCIs across multiple indices is unclear. OBJECTIVE: To use a Monte Carlo simulation procedure to estimate the normal rate (ie, base rate) of significant decline on 1 or more RCIs in multitest batteries. RESULTS & CONCLUSION: For batteries producing 7 or more uncorrelated RCIs (80% confidence intervals), the majority of normal individuals would show significant declines on at least 1 RCI. Expected rates are lower for tests with fewer indices, higher inter-RCI correlations, and more stringent impairment criteria. These reference points can help testers interpret RCI output for multitest batteries.

A construct-network approach to bridging diagnostic and physiological domains: application to assessment of externalizing psychopathology.

A crucial challenge in efforts to link psychological disorders to neural systems, with the aim of developing biologically informed conceptions of such disorders, is the problem of method variance (Campbell & Fiske, 1959). Since even measures of the same construct in differing domains correlate only moderately, it is unsurprising that large sample studies of diagnostic biomarkers yield only modest associations. To address this challenge, a construct-network approach is proposed in which psychometric operationalizations of key neurobehavioral constructs serve as anchors for identifying neural indicators of psychopathology-relevant dispositions, and as vehicles for bridging between domains of clinical problems and neurophysiology. An empirical illustration is provided for the construct of inhibition-disinhibition, which is of central relevance to problems entailing deficient impulse control. Findings demonstrate that: (1) a well-designed psychometric index of trait disinhibition effectively predicts externalizing problems of multiple types, (2) this psychometric measure of disinhibition shows reliable brain response correlates, and (3) psychometric and brain-response indicators can be combined to form a joint psychoneurometric factor that predicts effectively across clinical and physiological domains. As a methodology for bridging between clinical problems and neural systems, the construct-network approach provides a concrete means by which existing conceptions of psychological disorders can accommodate and be reshaped by neurobiological insights.