Impulsivity and Psychiatric Diagnoses as Mediators of Suicidal Ideation and Suicide Attempts Among Veterans With Traumatic Brain Injury.

OBJECTIVE: Traumatic brain injury (TBI) is a risk factor for suicide, but questions related to mechanisms remain unanswered. Impulsivity is a risk factor for suicide and is a common sequela of TBI. The authors explored the relationships between TBI and both suicidal ideation and suicide attempts and explored whether impulsivity and comorbid psychiatric diagnoses mediate these relationships. METHODS: This cross-sectional retrospective chart review study included 164 veterans enrolled in a previous study. Sixty-nine veterans had no TBI history, and 95 had a TBI history (mild, N=44; moderate, N=13; severe, N=12; and unclear severity, N=26). To examine the associations between TBI and suicidal ideation or suicide attempts, as well as potential mediators of these relationships, chi-square tests, t tests, and logistic regression models were used. RESULTS: Unadjusted analyses indicated that veterans with TBI were more likely to report suicidal ideation; however, in analyses controlling for mediators, this relationship was no longer significant. Among veterans with TBI, suicidal ideation was related most strongly to high impulsivity (odds ratio=15.35, 95% CI=2.43-96.79), followed by depression (odds ratio=5.73, 95% CI=2.53-12.99) and posttraumatic stress disorder (odds ratio=2.57, 95% CI=1.03-6.42). TBI was not related to suicide attempts, yet suicide attempts were related to high impulsivity (odds ratio=6.95, 95% CI=1.24-38.75) and depression (odds ratio=3.89, 95% CI=1.56-9.40). CONCLUSIONS: These findings suggest that impulsivity, followed by psychiatric diagnoses, most strongly mediate the relationships between TBI and both suicidal ideation and suicide attempts. Impulsivity may be mechanistically related to, and serve as a future treatment target for, suicidality among veterans with TBI.

Personality predicting relapse: A facet analysis of the NEO PI-R.

BACKGROUND AND OBJECTIVES: Revised NEO Personality Inventory (NEO PI-R) domains are associated with substance use disorders (SUD), including potential for relapse. However, individual facets of the NEO PI-R domains have not been rigorously analyzed. This paper assesses NEO PI-R individual facets among participants with SUD and their value in predicting relapse. METHODS: Between 2015 and 2018, all patients admitted to a single private rehabilitation center (n = 642) were offered participation in this study. Participants who completed NEO PI-R questionnaires at the start of treatment and with known relapse outcomes up to 1-year posttreatment were included (n = 441). Statistical analysis included a series of unadjusted univariate logistic regressions and additional adjusted multivariate regression controlling for employment status in healthcare. RESULTS: Neuroticism, Agreeableness, and Conscientiousness domains had significant impacts on relapse. Three individual facets of Neuroticism were significant predictors of relapse, and seven individual facets within the Conscientiousness and Agreeableness domains were inversely related to relapse. When controlling for employment, Conscientiousness and three of its individual facets (Dutifulness, Competence, and Self-Discipline) continued to be significant in predicting relapse. The individual facets Impulsiveness and Straightforwardness also continued to be significant in predicting relapse. CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE: Several personality domains and facets were significantly related to relapse, confirming and expanding on prior literature. This study focuses on the risk of relapse as it relates to NEO PI-R individual facets, which have not been previously explored with a sample size of this magnitude. These findings can guide clinical care of patients with SUD, allowing for more targeted treatment.

rTMS/iTBS and Cognitive Rehabilitation for Deficits Associated With TBI and PTSD: A Theoretical Framework and Review.

Rehabilitation of cognitive and psychosocial deficits resulting from traumatic brain injury (TBI) continues to be an area of concern in health care. Commonly co-occurring psychiatric disorders, such as major depressive disorder and posttraumatic stress disorder, create additional hurdles when attempting to remediate cognitive sequelae. There is increased need for procedures that will yield consistent gains indicative of recovery of function. Intermittent theta-burst stimulation (iTBS), a form of repetitive transcranial magnetic stimulation, has potential as an instrument that can be tailored to aid cognitive processes and support functional gains. The use of iTBS enables direct stimulation of desired neural systems. iTBS, performed in conjunction with behavioral interventions (e.g., cognitive rehabilitation, psychotherapy), may result in additive success in facilitating cognitive restoration and adaptation. The purpose of this theoretical review is to illustrate how the technical and physiological aspects of iTBS may enhance other forms of neurorehabilitation for individuals with TBI. Future research on combinatorial iTBS interventions has the potential to translate to other complex neuropsychiatric conditions.

An Initial miRNA Profile of Persons With Persisting Neurobehavioral Impairments and States of Disordered Consciousness After Severe Traumatic Brain Injury.

OBJECTIVE: To examine the merits of using microRNAs (miRNAs) as biomarkers of disorders of consciousness (DoC) due to traumatic brain injury (TBI). SETTINGS: Acute and subacute beds. PARTICIPANTS: Patients remaining in vegetative and minimally conscious states (VS, MCS), an average of 1.5 years after TBI, and enrolled in a randomized clinical trial ( n = 6). Persons without a diagnosed central nervous system disorder, neurotypical controls ( n = 5). DESIGN: Comparison of whole blood miRNA profiles between patients and age/gender-matched controls. For patients, correlational analyses between miRNA profiles and measures of neurobehavioral function. MAIN MEASURES: Baseline measures of whole blood miRNAs isolated from the cellular and fluid components of blood and measured using miRNA-seq and real-time polymerase chain reaction (RT-PCR). Baseline neurobehavioral measures derived from 7 tests. RESULTS: For patients, relative to controls, 48 miRNA were significantly ( P < .05)/differentially expressed. Cluster analysis showed that neurotypical controls were most similar to each other and with 2 patients (VS: n = 1; and MCS: n = 1). Three patients, all in MCS, clustered separately. The only female in the sample, also in MCS, formed an independent group. For the 48 miRNAs, the enriched pathways identified are implicated in secondary brain damage and 26 miRNAs were significantly ( P < .05) correlated with measures of neurobehavioral function. CONCLUSIONS: Patients remaining in states of DoC an average of 1.5 years after TBI showed a different and reproducible pattern of miRNA expression relative to age/gender-matched neurotypical controls. The phenotypes, defined by miRNA profiles relative to persisting neurobehavioral impairments, provide the basis for future research to determine the miRNA profiles differentiating states of DoC and the basis for future research using miRNA to detect treatment effects, predict treatment responsiveness, and developing targeted interventions. If future research confirms and advances reported findings, then miRNA profiles will provide the foundation for patient-centric DoC neurorehabilitation.

miRNAs as Potential Biomarkers for Traumatic Brain Injury: Pathway From Diagnosis to Neurorehabilitation.

BACKGROUND: Biomarkers that can advance precision neurorehabilitation of the traumatic brain injury (TBI) are needed. MicroRNAs (miRNAs) have biological properties that could make them well suited for playing key roles in differential diagnoses and prognoses and informing likelihood of responsiveness to specific treatments. OBJECTIVE: To review the evidence of miRNA alterations after TBI and evaluate the state of science relative to potential neurorehabilitation applications of TBI-specific miRNAs. METHODS: This scoping review includes 57 animal and human studies evaluating miRNAs after TBI. PubMed, Scopus, and Google Scholar search engines were used. RESULTS: Gold standard analytic steps for miRNA biomarker assessment are presented. Published studies evaluating the evidence for miRNAs as potential biomarkers for TBI diagnosis, severity, natural recovery, and treatment-induced outcomes were reviewed including statistical evaluation. Growing evidence for specific miRNAs, including miR21, as TBI biomarkers is presented. CONCLUSIONS: There is evidence of differential miRNA expression in TBI in both human and animal models; however, gaps need to be filled in terms of replication using rigorous, standardized methods to isolate a consistent set of miRNA changes. Longitudinal studies in TBI are needed to understand how miRNAs could be implemented as biomarkers in clinical practice.

Cognition and Other Predictors of Functional Disability Among Veterans With Mild Traumatic Brain Injury and Posttraumatic Stress Disorder.

BACKGROUND: Limitations in everyday functioning are frequently reported by veterans with a history of mild traumatic brain injury (mTBI) and/or posttraumatic stress disorder (PTSD). Multiple factors are associated with functional disability among veterans, including depression, poor social support, cognition, and substance use. However, the degree to which these factors, particularly cognitive capacities, contribute to functional limitations remains unclear. METHODS: We evaluated performance on tests of processing speed, executive functioning, attention, and memory as predictors of functioning on the World Health Organization Disability Assessment Scale (WHODAS) 2.0 in 288 veterans. Participants were placed in one of the following groups: PTSD-only, mTBI-only, mTBI + PTSD, and neither PTSD nor mTBI (deployed control group). Cognitive test performances were evaluated as predictors of WHODAS 2.0 functional ratings in regression models that included demographic variables and a range of mood, behavioral health, and postconcussive symptom ratings. RESULTS: Multiple cognitive test performances predicted WHODAS 2.0 scores in the deployed control group, but they generally did not predict functioning in the clinical groups when accounting for demographics, mood, behavioral health, and postconcussive symptoms. CONCLUSIONS: In veterans with mTBI and/or PTSD, cognitive test performances are less associated with everyday functioning than mood and postconcussive symptoms.

Customizing TMS Applications in Traumatic Brain Injury Using Neuroimaging.

Optimizing transcranial magnetic stimulation (TMS) treatments in traumatic brain injury (TBI) and co-occurring conditions may benefit from neuroimaging-based customization. PARTICIPANTS: Our total sample (N = 97) included 58 individuals with TBI (49 mild, 8 moderate, and 1 severe in a state of disordered consciousness), of which 24 had co-occurring conditions (depression in 14 and alcohol use disorder in 10). Of those without TBI, 6 individuals had alcohol use disorder and 33 were healthy controls. Of our total sample, 54 were veterans and 43 were civilians. DESIGN: Proof-of-concept study incorporating data from 5 analyses/studies that used multimodal approaches to integrate neuroimaging with TMS. MAIN MEASURES: Multimodal neuroimaging methods including structural magnetic resonance imaging (MRI), MRI-guided TMS navigation, functional MRI, diffusion MRI, and TMS-induced electric fields. Outcomes included symptom scales, neuropsychological tests, and physiological measures. RESULTS: It is feasible to use multimodal neuroimaging data to customize TMS targets and understand brain-based changes in targeted networks among people with TBI. CONCLUSIONS: TBI is an anatomically heterogeneous disorder. Preliminary evidence from the 5 studies suggests that using multimodal neuroimaging approaches to customize TMS treatment is feasible. To test whether this will lead to increased clinical efficacy, studies that integrate neuroimaging and TMS targeting data with outcomes are needed.

A Pilot Trial Examining the Merits of Combining Amantadine and Repetitive Transcranial Magnetic Stimulation as an Intervention for Persons With Disordered Consciousness After TBI.

OBJECTIVE: Report pilot findings of neurobehavioral gains and network changes observed in persons with disordered consciousness (DoC) who received repetitive transcranial magnetic stimulation (rTMS) or amantadine (AMA), and then rTMS+AMA. PARTICIPANTS: Four persons with DoC 1 to 15 years after traumatic brain injury (TBI). DESIGN: Alternate treatment-order, within-subject, baseline-controlled trial. MAIN MEASURES: For group and individual neurobehavioral analyses, predetermined thresholds, based on mixed linear-effects models and conditional minimally detectable change, were used to define meaningful neurobehavioral change for the Disorders of Consciousness Scale-25 (DOCS) total and Auditory-Language measures. Resting-state functional connectivity (rsFC) of the default mode and 6 other networks was examined. RESULTS: Meaningful gains in DOCS total measures were observed for 75% of treatment segments and auditory-language gains were observed after rTMS, which doubled when rTMS preceded rTMS+AMA. Neurobehavioral changes were reflected in rsFC for language, salience, and sensorimotor networks. Between networks interactions were modulated, globally, after all treatments. CONCLUSIONS: For persons with DoC 1 to 15 years after TBI, meaningful neurobehavioral gains were observed after provision of rTMS, AMA, and rTMS+AMA. Sequencing and combining of treatments to modulate broad-scale neural activity, via differing mechanisms, merits investigation in a future study powered to determine efficacy of this approach to enabling neurobehavioral recovery.

Eye movement performance and clinical outcomes among female athletes post-concussion.

BACKGROUND: Most post-concussion eye movement (EM) research involves predominantly male samples. We evaluated pro- (PRO; reflexive shift of visual attention to target) and anti- (ANTI; executive control of visual attention away from target) computer-based saccade task performance among female, collegiate athletes with recent concussion (CON) versus healthy-control athletes (HC). We evaluated the relationship between EM performance and post-concussion outcomes. We hypothesized ANTI performance would differ among CON and HC due to greater executive control demands, and that EM performance (both tasks) would be associated with clinical outcomes in CON. METHODS: 16 CON (assessed 4-10 days post-injury [M = 6.87, SD = 2.15 days]) and 16 age-matched HC athletes were recruited. General linear mixed modeling and Pearson's correlations were used. RESULTS: On ANTI, CON demonstrated higher error rate [F(1,2863) = 12.650, p<.001] and shorter latency on error trials [F(1,469) = 5.976, p=.015] relative to HC. Multiple EM measures were associated with clinical outcomes: PRO duration predicted days to symptom remission (r=.44, p <.05); ANTI error rate was associated with symptom burden on the day of testing (r=.27, p <.05). CONCLUSION: This study demonstrates promising utility of EM measures to detect cognitive control and sensorimotor effects of concussion among female athletes and their use as a prognostic indicators of recovery.

Overview of pharmacological interventions after traumatic brain injuries: impact on selected outcomes.

The purpose of this study was to conduct an overview of systematic reviews (SRs) to appraise the published evidence related to pharmacological interventions after traumatic brain injury (TBI). Searches were conducted with Medline, Embase, PsycINFO, Web of Science, PubMed. 780 retrieved SRs underwent a two-level screening to determine inclusion. Data extracted included participant characteristics, TBI severity, study design, pharmacological interventions, and outcomes. SRs were assessed for methodological quality by using the AMSTAR measurement tool. After removing duplicates, 166/780 SRs published between 1990-2017 were reviewed, 62 of which met inclusion criteria. More than 90 drugs and 22 substance-classes were extracted. Most medications were administered during the acute stage. Mild TBI was included in 3% of the SRs. Physiological outcomes comprised 45% of the SRs, primarily mortality. Activities of daily living (ADLs) outcomes constituted 22% of the SRs followed by cognition (13%) and psychological/behavioral outcomes (13%). Only 7% of the SRs assessed adverse events. Inconsistencies in definitions, methods, and heterogeneity of instruments used to measure treatment response were noted. Only a third of the SRs had high methodological quality. Most SRs had heterogeneous TBI samples, outcomes, or methodologies making it difficult to synthesize findings into recommended guidelines. This study demonstrated a need for adequately powered and rigorous randomized clinical trials (RCTs) to provide generalizable evidence on the effectiveness of pharmacologic interventions for TBI. PROSPERO Registration: CRD42015017355.

Diagnostic Accuracy of the Veteran Affairs' Traumatic Brain Injury Screen.

OBJECTIVE: To comprehensively estimate the diagnostic accuracy and reliability of the Department of Veterans Affairs (VA) Traumatic Brain Injury (TBI) Clinical Reminder Screen (TCRS). DESIGN: Cross-sectional, prospective, observational study using the Standards for Reporting of Diagnostic Accuracy criteria. SETTING: Three VA Polytrauma Network Sites. PARTICIPANTS: Operation Iraqi Freedom, Operation Enduring Freedom veterans (N=433). MAIN OUTCOME MEASURES: TCRS, Comprehensive TBI Evaluation, Structured TBI Diagnostic Interview, Symptom Attribution and Classification Algorithm, and Clinician-Administered Posttraumatic Stress Disorder (PTSD) Scale. RESULTS: Forty-five percent of veterans screened positive on the TCRS for TBI. For detecting occurrence of historical TBI, the TCRS had a sensitivity of .56 to .74, a specificity of .63 to .93, a positive predictive value (PPV) of 25% to 45%, a negative predictive value (NPV) of 91% to 94%, and a diagnostic odds ratio (DOR) of 4 to 13. For accuracy of attributing active symptoms to the TBI, the TCRS had a sensitivity of .64 to .87, a specificity of .59 to .89, a PPV of 26% to 32%, an NPV of 92% to 95%, and a DOR of 6 to 9. The sensitivity was higher for veterans with PTSD (.80-.86) relative to veterans without PTSD (.57-.82). The specificity, however, was higher among veterans without PTSD (.75-.81) relative to veterans with PTSD (.36-.49). All indices of diagnostic accuracy changed when participants with questionably valid (QV) test profiles were eliminated from analyses. CONCLUSIONS: The utility of the TCRS to screen for mild TBI (mTBI) depends on the stringency of the diagnostic reference standard to which it is being compared, the presence/absence of PTSD, and QV test profiles. Further development, validation, and use of reproducible diagnostic algorithms for symptom attribution after possible mTBI would improve diagnostic accuracy.

Algorithm for Symptom Attribution and Classification Following Possible Mild Traumatic Brain Injury.

OBJECTIVE: To present a heuristic model of a symptom attribution and classification algorithm (SACA) for mild traumatic brain injury (mTBI). SETTING: VA Polytrauma sites. PARTICIPANTS: 422 Veterans. DESIGN: Cross-sectional. MAIN MEASURES: SACA, Comprehensive TBI Evaluation (CTBIE), Structured TBI Diagnostic Interview, Minnesota Multiphasic Personality Inventory (MMPI-2-RF), Letter Memory Test, Validity-10. RESULTS: SACA and CTBIE diagnoses differ significantly (P < .01). The CTBIE, compared with SACA, attributes 16% to 500% more symptoms to mTBI, behavioral health (BH), mTBI + BH and symptom resolution. Altering SACA criteria indicate that (1) CTBIE determination of cognitive impairment yields 27% to 110% more mTBI, mTBI + BH and symptom resolution diagnoses, (2) ignoring timing of symptom onset yields 32% to 76% more mTBI, mTBI + BH and Other Condition diagnoses, (3) Proportion of sample having questionably valid profiles using structured TBI diagnostic interview and MMPI-2-RF and Letter Memory Test is 26% whereas with CTBIE item number 23 and Validity-10 is 6% to 26%, (4) MMPI-2-RF F-scale is the only measure identifying Veterans with posttraumatic amnesia for more than 24 hours as having questionably valid profiles. CONCLUSIONS: Symptom attribution-based diagnoses differ when using status quo versus the SACA. The MMPI-2-RF F-scale, compared with the Validity-10 and Letter Memory Test, may be more precise in identifying questionably valid profiles for mTBI + BH. The SACA provides a framework to inform clinical practice, resource allocation, and future research.

Prescribing multiple neurostimulants during rehabilitation for severe brain injury.

BACKGROUND: Despite a lack of clear evidence, multiple neurostimulants are commonly provided after severe brain injury (BI). The purpose of this study is to determine if the number of neurostimulants received during rehabilitation was associated with recovery of full consciousness or improved neurobehavioral function after severe BI. METHOD: Data from 115 participants were extracted from a neurobehavioral observational study database for this exploratory, retrospective analysis. Univariate optimal data analysis was conducted to determine if the number of neurostimulants influenced classification of four outcomes: recovery of full consciousness during rehabilitation, recovery of full consciousness within one year of injury, and meaningful neurobehavioral improvement during rehabilitation defined as either at least a 4.7 unit (minimal detectable change) or 2.58 unit (minimal clinically important difference) gain on the Disorders of Consciousness Scale-25 (DOCS-25). RESULTS: Number of neurostimulants was not significantly (P > 0.05) associated with recovery of full consciousness during rehabilitation, within one year of injury, or meaningful neurobehavioral improvement using the DOCS-25. CONCLUSIONS: Receiving multiple neurostimulants during rehabilitation may not influence recovery of full consciousness or meaningful neurobehavioral improvement. Given costs associated with additional medication, future research is needed to guide physicians about the merits of prescribing multiple neurostimulants during rehabilitation after severe BI.

Cellular distribution of AMPA receptor subunits and mGlu5 following acute and repeated administration of morphine or methamphetamine.

Ionotropic AMPA receptors (AMPAR) and metabotropic glutamate group I subtype 5 receptors (mGlu5) mediate neuronal and behavioral effects of abused drugs. mGlu5 stimulation increases expression of striatal-enriched tyrosine phosphatase isoform 61 (STEP61 ) which internalizes AMPARs. We determined the rat brain profile of these proteins using two different classes of abused drugs, opiates, and stimulants. STEP61 levels, and cellular distribution/expression of AMPAR subunits (GluA1, GluA2) and mGlu5, were evaluated via a protein cross-linking assay in medial prefrontal cortex (mPFC), nucleus accumbens (NAc), and ventral pallidum (VP) harvested 1 day after acute, or fourteen days after repeated morphine (8 mg/kg) or methamphetamine (1 mg/kg) (treatments producing behavioral sensitization). Acute morphine decreased GluA1 and GluA2 surface expression in mPFC and GluA1 in NAc. Fourteen days after repeated morphine or methamphetamine, mGlu5 surface expression increased in VP. In mPFC, mGlu5 were unaltered; however, after methamphetamine, STEP61 levels decreased and GluA2 surface expression increased. Pre-treatment with a mGlu5-selective negative allosteric modulator, blocked methamphetamine-induced behavioral sensitization and changes in mPFC GluA2 and STEP61 . These data reveal (i) region-specific distinctions in glutamate receptor trafficking between acute and repeated treatments of morphine and methamphetamine, and (ii) that mGlu5 is necessary for methamphetamine-induced alterations in mPFC GluA2 and STEP61 .

Feasibility of a Combined Neuromodulation and Yoga Intervention for Mild Traumatic Brain Injury and Chronic Pain: Protocol for an Open-label Pilot Trial.

BACKGROUND: Mild traumatic brain injury (mTBI) and chronic pain often co-occur and worsen rehabilitation outcomes. There is a need for improved multimodal nonpharmacologic treatments that could improve outcomes for both conditions. Yoga is a promising activity-based intervention for mTBI and chronic pain, and neuromodulation through transcranial magnetic stimulation is a promising noninvasive, nonpharmacological treatment for mTBI and chronic pain. Intermittent theta burst stimulation (iTBS) is a type of patterned, excitatory transcranial magnetic stimulation. iTBS can induce a window of neuroplasticity, making it ideally suited to boost the effects of treatments provided after it. Thus, iTBS may magnify the impacts of subsequently delivered interventions as compared to delivering those interventions alone and accordingly boost their impact on outcomes. OBJECTIVE: The aim of this study is to (1) develop a combined iTBS+yoga intervention for mTBI and chronic pain, (2) assess the intervention's feasibility and acceptability, and (3) gather preliminary clinical outcome data on quality of life, function, and pain that will guide future studies. METHODS: This is a mixed methods, pilot, open-labeled, within-subject intervention study. We will enroll 20 US military veteran participants. The combined iTBS+yoga intervention will be provided in small group settings once a week for 6 weeks. The yoga intervention will follow the LoveYourBrain yoga protocol-specifically developed for individuals with TBI. iTBS will be administered immediately prior to the LoveYourBrain yoga session. We will collect preliminary quantitative outcome data before and after the intervention related to quality of life (TBI-quality of life), function (Mayo-Portland Adaptability Index), and pain (Brief Pain Inventory) to inform larger studies. We will collect qualitative data via semistructured interviews focused on intervention acceptability after completion of the intervention. RESULTS: This study protocol was approved by Edward Hines Jr Veterans Administration Hospital Institutional Review Board (Hines IRB 1573116-4) and was prospectively registered on ClinicalTrials.gov (NCT04517604). This study includes a Food and Drug Administration Investigational Device Exemption (IDE: G200195). A 2-year research plan timeline was developed. As of March 2022, a total of 6 veterans have enrolled in the study. Data collection is ongoing and will be completed by November 2022. We expect the results of this study to be available by October 2024. CONCLUSIONS: We will be able to provide preliminary evidence of safety, feasibility, and acceptability of a novel combined iTBS and yoga intervention for mTBI and chronic pain-conditions with unmet treatment needs. TRIAL REGISTRATION: ClinicalTrials.gov NCT04517604; https://www.clinicaltrials.gov/ct2/show/NCT04517604. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/37836.

Brain region-selective cellular redistribution of mGlu5 but not GABA(B) receptors following methamphetamine-induced associative learning.

Alterations in receptor expression and distribution between cell surface and cytoplasm are means by which psychostimulants regulate neurotransmission. Metabotropic glutamate receptor group I, subtype 5 (mGluR5) and GABA(B) receptors (GABA(B) R) are critically involved in the development and expression of stimulant-induced behaviors, including conditioned place preference (CPP), an index of drug-seeking. However, it is not known if psychostimulant-induced CPP alters the trafficking of these receptors. To fill this gap, this study used methamphetamine (Meth)-induced CPP in rats to ascertain if receptor changes occur in limbic brain regions that regulate drug-seeking, the medial prefrontal cortex (mPFC), nucleus accumbens (NAc), and ventral pallidum (VP). To do so, ex vivo tissue was assessed for changes in expression and surface vs. intracellular distribution of mGluR5 and GABA(B) Rs. There was a decrease in the surface to intracellular ratio of mGluR5 in the mPFC in Meth-conditioned rats, commensurate with an increase in intracellular levels. mGluR5 levels in the NAc or the VP were unaltered. There were no changes for GABA(B) R in any brain region assayed. This ex vivo snapshot of metabotropic glutamate and GABA receptor cellular distribution following induction of Meth-induced CPP is the first report to determine if these receptors are differentially altered after Meth-induced CPP. The results suggest that this Meth treatment paradigm likely induced a compensatory change in mGluR5 surface to intracellular ratio such that the surface remains unaltered while an increase in intracellular protein occurred.

Preliminary Report: Localized Cerebral Blood Flow Mediates the Relationship between Progesterone and Perceived Stress Symptoms among Female Collegiate Club Athletes after Mild Traumatic Brain Injury.

Female athletes are under-studied in the field of concussion research, despite evidence of higher injury prevalence and longer recovery time. Hormonal fluctuations caused by the natural menstrual cycle (MC) or hormonal contraceptive (HC) use impact both post-injury symptoms and neuroimaging findings, but the relationships among hormone, symptoms, and brain-based measures have not been jointly considered in concussion studies. In this preliminary study, we compared cerebral blood flow (CBF) measured with arterial spin labeling between concussed female club athletes 3-10 days after mild traumatic brain injury (mTBI) and demographic, HC/MC matched controls (CON). We tested whether CBF statistically mediates the relationship between progesterone serum levels and post-injury symptoms, which may support a hypothesis for progesterone's role in neuroprotection. We found a significant three-way relationship among progesterone, CBF, and perceived stress score (PSS) in the left middle temporal gyrus for the mTBI group. Higher progesterone was associated with lower (more normative) PSS, as well as higher (more normative) CBF. CBF mediates 100% of the relationship between progesterone and PSS (Sobel p value = 0.017). These findings support a hypothesis for progesterone having a neuroprotective role after concussion and highlight the importance of controlling for the effects of sex hormones in future concussion studies.

Brain Perfusion Bridges Virtual-Reality Spatial Behavior to TPH2 Genotype for Head Acceleration Events.

Neuroimaging demonstrates that athletes of collision sports can suffer significant changes to their brain in the absence of concussion, attributable to head acceleration event (HAE) exposure. In a sample of 24 male Division I collegiate football players, we examine the relationships between tryptophan hydroxylase 2 (TPH2), a gene involved in neurovascular function, regional cerebral blood flow (rCBF) measured by arterial spin labeling, and virtual reality (VR) motor performance, both pre-season and across a single football season. For the pre-season, TPH2 T-carriers showed lower rCBF in two left hemisphere foci (fusiform gyrus/thalamus/hippocampus and cerebellum) in association with higher (better performance) VR Reaction Time, a dynamic measure of sensory-motor reactivity and efficiency of visual-spatial processing. For TPH2 CC homozygotes, higher pre-season rCBF in these foci was associated with better performance on VR Reaction Time. A similar relationship was observed across the season, where TPH2 T-carriers showed improved VR Reaction Time associated with decreases in rCBF in the right hippocampus/amygdala, left middle temporal lobe, and left insula/putamen/pallidum. In contrast, TPH2 CC homozygotes showed improved VR Reaction Time associated with increases in rCBF in the same three clusters. These findings show that TPH2 T-carriers have an abnormal relationship between rCBF and the efficiency of visual-spatial processing that is exacerbated after a season of high-impact sports in the absence of diagnosable concussion. Such gene-environment interactions associated with behavioral changes after exposure to repetitive HAEs have been unrecognized with current clinical analytical tools and warrant further investigation. Our results demonstrate the importance of considering neurovascular factors along with traumatic axonal injury to study long-term effects of repetitive HAEs.

Psychometric measurement properties of the world health organization disability assessment schedule 2.0 (WHODAS) evaluated among veterans with mild traumatic brain injury and behavioral health conditions.

PURPOSE: Examine the psychometric properties of the World Health Organization Disability Assessment Schedule 2.0 among U.S. Iraq/Afghanistan Veterans with a combination of mild traumatic brain injury and behavioral health conditions using Rasch analysis. METHODS: 307 Veterans were classified as either combat control (n = 141), or one of three clinical groups: mild traumatic brain injury (n = 10), behavioral health conditions (n = 24), or both (n = 128). Data from the three clinical groups were used to establish step and item calibrations serving as anchors when including the control group. RESULTS: Measurement precision was excellent (person separation reliability = 0.93). Ordering of item calibrations formed a logical hierarchy. Test items were off-target (too easy) for the clinical groups. Principal component analysis indicated unidimensionality although 4/36 items misfit the measurement model. No meaningful differential item functioning was detected. There was a moderate effect size (Hedge's g = 1.64) between the control and clinical groups. CONCLUSIONS: The World Health Organization Disability Assessment Schedule was suitable for our study sample, distinguishing 4 levels of functional ability. Although items may be easy for some Veterans with mild traumatic brain injury and/or behavioral health conditions, the World Health Organization Disability Assessment Schedule can be used to capture disability information for those with moderate to severe disability.Implications for rehabilitationPersistent functional disability is seen in military and civilian populations with mild traumatic brain injury which often co-occurs with behavioral health conditions.A comprehensive measure of disability is needed to distinguish between levels of disability to inform clinical decisions for individual patients and to detect treatment effects between groups in research.Results of this analysis indicate the World Health Organization Disability Assessment Schedule items are sufficiently unidimensional to evaluate level of disability in the moderate and severe range among persons with mild traumatic brain injury with and without behavioral health conditions.Further examination of the psychometric properties of the World Health Organization.Disability Assessment Schedule is necessary before measurement of disability is recommended for those with less than moderate levels of disability.