Psychiatric aspects of traumatic brain injury

Cognitive behavioral therapy for managing depressive and anxiety symptoms after brain injury: a meta-analysis

BACKGROUND

Individuals with traumatic brain injury (TBI) are at increased risk of depression and anxiety, leading to impaired recovery. While cognitive-behavioral therapy (CBT) addresses anxiety and depression maintenance factors, its efficacy among those with TBI has not been clearly demonstrated. This review aims to bridge this gap in the literature.

METHODS

Several databases, including Medline, PsycInfo and EMBASE, were used to identify studies published between 1990 and 2021. Studies were included if: (1) trials were randomized controlled trials (RCT) involving CBT-based intervention targeting anxiety and/or depression; (2) participants experienced brain injury at least 3-months previous; (3) participants were ≥18 years old. An SMD ± SE, 95% CI and heterogeneity were calculated for each outcome.

RESULTS

Thirteen RCTs were included in this meta-analysis. The pooled-sample analyses suggest that CBT interventions had small immediate post-treatment effects on reducing depression (SMD ± SE: 0.391 ± 0.126, p < 0.005) and anxiety (SMD ± SE: 0.247 ± 0.081, p < 0.005). Effects were sustained at a 3-months follow-up for depression. A larger effect for CBT was seen when compared with supportive therapy than control. Another sub-analysis found that individualized CBT resulted in a slightly higher effect compared to group-based CBT.

CONCLUSION

This meta-analysis provides substantial evidence for CBT in managing anxiety and depression post-TBI.

Brain Injury Effects on Neuronal Activation and Synaptic Transmission in the Basolateral Amygdala of Adult Male and Female Wistar Rats

Traumatic brain injury (TBI) is defined as brain damage produced by an external mechanical force that leads to behavioral, cognitive, and psychiatric sequelae. The basolateral amygdala (BLA) is involved in emotional regulation, and its function and morphology are altered following TBI. Little is known about potential sex-specific effects of TBI on BLA neuronal function, but it is critical for the field to identify potential sex differences in TBI effects on brain and behavior. Here, we hypothesized that TBI would produce sex-specific acute (1 h) effects on BLA neuronal activation, excitability, and synaptic transmission in adult male and female rats. Forty-nine Wistar rats (n = 23 males and 26 females) were randomized to TBI (using lateral fluid percussion) or Sham groups in two separate studies. Study 1 used in situ hybridization (i.e., RNAscope) to measure BLA expression of c-fos (a marker of cell activation), vGlut, and vGat (markers of glutamatergic and GABAergic neurons, respectively) messenger RNA (mRNA). Study 2 used slice electrophysiology to measure intrinsic excitability and excitatory/inhibitory synaptic transmission in putative pyramidal neurons in the BLA. Physiological measures of injury severity were collected from all animals. Our results show that females exhibit increased apnea duration and reduced respiratory rate post-TBI relative to males. In male and female rats, TBI increased c-fos expression in BLA glutamatergic cells but not in BLA GABAergic cells, and TBI increased firing rate in BLA pyramidal neurons. Further, TBI increased spontaneous excitatory and inhibitory postsynaptic current (sEPSC and sIPSC) amplitude in BLA neurons of females relative to all other groups. TBI increased sEPSC frequency in BLA neurons of females relative to males but did not alter sIPSC frequency. In summary, lateral fluid percussion produced different physiological responses in male and female rats, as well as sex-specific alterations in BLA neuronal activation, excitability, and synaptic transmission 1 h after injury.

Acetylcholinesterase inhibitors to enhance recovery from traumatic brain injury: a comprehensive review and case series

OBJECTIVE

Acetylcholinesterase inhibitors (AChEIs) are used off-label, in both adult and pediatric patients, to help further neuro-recovery after traumatic brain injury (TBI). Evidence is limited and piecemeal. This review describes how TBI affects the cholinergic system and consolidates evidence supporting or refuting the use of AChEIs following TBI.

METHODS

NCBI MEDLINE search included all articles published through March 2021 on AChEI use in acute and post-acute adult TBI rehabilitation (treatment began <90 days or ≥90 days since injury, respectively), and in pediatric TBI rehabilitation. Further, we checked ClinicalTrials.gov for ongoing trials using AChEIs for TBI rehabilitation in the United States.

RESULTS

27 original articles from NCBI Medline, published through March 2021, were included. The use of AChEIs following TBI in acute and post-acute rehabilitation settings, in both adult and pediatric patients, along with medication side effects, is discussed.

CONCLUSIONS

Most studies showed benefits with only moderate effect sizes because of small sample sizes. Reported side effects are minimal and stop soon after AChEIs is discontinued. Conclusions are limited by paucity of research; but fortunately, a large randomized controlled trial is ongoing, and more are needed to truly determine the efficacy of AChEIs in helping with recovery from TBI.

The effectiveness of cognitive behaviour therapy for reducing anxiety symptoms following traumatic brain injury: A meta-analysis and systematic review

BACKGROUND

Anxiety is a common neuropsychological sequela following traumatic brain injury (TBI). Cognitive Behaviour Therapy (CBT) is a recommended, first-line intervention for anxiety disorders in the non-TBI clinical population, however its effectiveness after TBI remains unclear and findings are inconsistent.

OBJECTIVE

There are no current meta-analyses exploring the efficacy of CBT as an intervention for anxiety symptoms following TBI, using controlled trials. The aim of the current study, therefore, was to systematically review and synthesize the evidence from controlled trials for the effectiveness of CBT for anxiety, specifically within the TBI population.

METHOD

Three electronic databases (Web of Science, PubMed and PsycInfo) were searched and a systematic review of intervention studies utilising CBT and anxiety related outcome measures in a TBI population was performed through searching three electronic databases. Studies were further evaluated for quality of evidence based on Reichow's (2011) quality appraisal tool. Baseline and outcome data were extracted from the 10 controlled trials that met the inclusion criteria, and effect sizes were calculated.

RESULTS

A random effects meta-analysis identified a small overall effect size (Cohen's d) of d = -0.26 (95%CI -0.41 to -0.11) of CBT interventions reducing anxiety symptoms following TBI.

CONCLUSIONS

This meta-analysis tentatively supports the view that CBT interventions may be effective in reducing anxiety symptoms in some patients following TBI, however the effect sizes are smaller than those reported for non-TBI clinical populations. Clinical implications and limitations of the current meta-analysis are discussed.

[Combat stress and organic brain injury: type of the dynamics of posttraumatic stress disorder]

OBJECTIVE

To study a role of traumatic brain injury (TBI) in the development of posttraumatic stress disorder (PTSD) in ex combatants.

MATERIAL AND METHODS

Eighty-seven ex combatants were studied. The duration of follow-up was 15-18 years. The diagnosis was established in accordance with ICD-10 criteria. Patients were stratified by diagnosis into main group (PTSD) and comparison group (organic brain injury with reduced symptoms of PTSD ). A psychopathological method and a battery of questionnaires and scales, including those adapted for assessment of consequences of combat trauma, were administered.

RESULTS AND CONCLUSION

Clinical presentations of both groups in posttraumatic period show the similarity and homogeneity of posttraumatic disorders in these groups. In the future, the pathogenetic role of TBI severity appears more clearly, which, depending on the severity, leads to the formation of an organic lesion of the brain or performs only a pathoplastic role, giving some features to the clinical picture of PTSD. It was found that the more severe the injury, the greater the likelihood of PTSD transition to organic brain damage. It is emphasized that PTSD treatment is a continuous, long-term, complex and graded process that includes pharmacotherapy, psychotherapy, psychosocial interventions.

Traumatic brain injury and the misuse of alcohol, opioids, and cannabis

Traumatic brain injury (TBI), most often classified as concussion, is caused by biomechanical forces to the brain resulting in short- or long-term impairment in brain function. TBI resulting from military combat, sports, violence, falls, and vehicular accidents is a major cause of long-term physical, cognitive, and psychiatric dysfunction. Psychiatric disorders associated with TBI include depression, anxiety, and substance use disorder, all having significant implications for post-TBI recovery and rehabilitation. This chapter reviews the current preclinical and clinical literature describing the bidirectional relationship between TBI and misuse of three commonly abused drugs: alcohol, opioids, and cannabis. We highlight the influence of each of these drugs on the incidence of TBI, as well as trends in their use after TBI. Furthermore, we discuss factors that may underlie post-injury substance use. Understanding the complex relationship between TBI and substance misuse will enhance the clinical treatment of individuals suffering from these two highly comorbid conditions.

Catastrophic consequences: can the feline parasite Toxoplasma gondii prompt the purrfect neuroinflammatory storm following traumatic brain injury?

Traumatic brain injury (TBI) is one of the leading causes of morbidity and mortality worldwide; however, treatment development is hindered by the heterogenous nature of TBI presentation and pathophysiology. In particular, the degree of neuroinflammation after TBI varies between individuals and may be modified by other factors such as infection. Toxoplasma gondii, a parasite that infects approximately one-third of the world’s population, has a tropism for brain tissue and can persist as a life-long infection. Importantly, there is notable overlap in the pathophysiology between TBI and T. gondii infection, including neuroinflammation. This paper will review current understandings of the clinical problems, pathophysiological mechanisms, and functional outcomes of TBI and T. gondii, before considering the potential synergy between the two conditions. In particular, the discussion will focus on neuroinflammatory processes such as microglial activation, inflammatory cytokines, and peripheral immune cell recruitment that occur during T. gondii infection and after TBI. We will present the notion that these overlapping pathologies in TBI individuals with a chronic T. gondii infection have the strong potential to exacerbate neuroinflammation and related brain damage, leading to amplified functional deficits. The impact of chronic T. gondii infection on TBI should therefore be investigated in both preclinical and clinical studies as the possible interplay could influence treatment strategies.

Predicting mood outcome following traumatic brain injury (TBI): PTA & demographic variables

Background and aims:

Mood disturbance is frequent after traumatic brain injury (TBI), often assessed using the Hospital Anxiety and Depression Scale (HADS). Research supports a three-factor HADS structure (anxiety, depression, and psychomotor), although this has not been used to investigate demographic variables and mood outcome post-TBI. This study examined severity of TBI, demographic variables [age, gender, estimated premorbid IQ (EIQ), relationship status, employment status, socio-economic status (SES)], and mood outcome, using HADS factor scores from a large adult population sample in Tasmania.

Method:

HADS factor scores were calculated for an initial sample of 596 adults. The sample sizes varied according to those attending at 1, 6, 12 and 24 months post-TBI and the available data for each dependent variable.

Results:

Significantly higher anxiety, depression, and psychomotor scores were reported at most follow-ups by females, the middle-aged, and those with lower IQs. Longer post-traumatic amnesia (PTA) was associated with significantly greater mood problems. Occasional significant findings at earlier follow-ups for the factors were noted for those unemployed. Other variables were rarely significant. PTA, premorbid IQ, and Age were included in most Multiple Regression equations predicting outcome for the factors, with Gender included for Anxiety and depression at 6 months after injury.

Conclusions:

Key demographic variables and PTA severity relate to mood post-TBI, and contribute to predicting mood outcome. Differences in findings for the three factors support their use in clinical practice.

Long-Term Effects of Traumatic Brain Injury on Anxiety-Like Behaviors in Mice: Behavioral and Neural Correlates

Traumatic brain injury (TBI) has been frequently linked to affective disorders such as anxiety and depression. However, much remains to be understood about the underlying molecular and signaling mechanisms that mediate affective dysfunctions following injury. A lack of consensus in animal studies regarding what the affective sequelae of TBI are has been a major hurdle that has slowed progress, with studies reporting the full range of effects: increase, decrease, and no change in anxiety following injury. Here, we addressed this issue directly by investigating long-term anxiety outcomes in mice following a moderate to severe controlled cortical impact (CCI) injury using a battery of standard behavioral tests-the open field (OF), elevated zero maze (EZM), and elevated plus maze (EPM). Mice were tested on weeks 1, 3, 5 and 7 post-injury. Our results show that the effect of injury is time- and task-dependent. Early on-up to 3 weeks post-injury, there is an increase in anxiety-like behaviors in the elevated plus and zero mazes. However, after 5 weeks post-injury, anxiety-like behavior decreases, as measured in the OF and EZM. Immunostaining in the basolateral amygdala (BLA) for GAD, a marker for GABA, at the end of the behavioral testing showed the late decrease in anxiety behavior was correlated with upregulation of inhibition. The approach adopted in this study reveals a complex trajectory of affective outcomes following injury, and highlights the importance of comparing outcomes in different assays and time-points, to ensure that the affective consequences of injury are adequately assessed.

Effects of Mild Blast Traumatic Brain Injury on Cognitive- and Addiction-Related Behaviors

Traumatic brain injury (TBI) commonly results in cognitive and psychiatric problems. Cognitive impairments occur in approximately 30% of patients suffering from mild TBI (mTBI), and correlational evidence from clinical studies indicates that substance abuse may be increased following mTBI. However, understanding the lasting cognitive and psychiatric problems stemming from mTBI is difficult in clinical settings where pre-injury assessment may not be possible or accurate. Therefore, we used a previously characterized blast model of mTBI (bTBI) to examine cognitive- and addiction-related outcomes. We previously demonstrated that this model leads to bilateral damage of the medial prefrontal cortex (mPFC), a region critical for cognitive function and addiction. Rats were exposed to bTBI and tested in operant learning tasks several weeks after injury. bTBI rats made more errors during acquisition of a cue discrimination task compared to sham treated rats. Surprisingly, we observed no differences between groups in set shifting and delayed matching to sample, tasks known to require the mPFC. Separate rats performed cocaine self-administration. No group differences were found in intake or extinction, and only subtle differences were observed in drug-primed reinstatement 3-4 months after injury. These findings indicate that bTBI impairs acquisition of a visual discrimination task and that bTBI does not significantly increase the ability of cocaine exposure to trigger drug seeking.

Effect of Aerobic Exercise Training on Mood in People With Traumatic Brain Injury: A Pilot Study

BACKGROUND

Exercise training is associated with elevations in mood in patients with various chronic illnesses and disabilities. However, little is known regarding the effect of exercise training on short and long-term mood changes in those with traumatic brain injury (TBI).

OBJECTIVE

The purpose of this study was to examine the time course of mood alterations in response to a vigorous, 12-week aerobic exercise training regimen in ambulatory individuals with chronic TBI (>6 months postinjury).

METHODS

Short and long-term mood changes were measured using the Profile of Mood States-Short Form, before and after specific aerobic exercise bouts performed during the 12-week training regimen.

RESULTS

Ten subjects with nonpenetrating TBI (6.6 ± 6.8 years after injury) completed the training regimen. A significant improvement in overall mood was observed following 12 weeks of aerobic exercise training (P = .04), with moderate to large effect sizes observed for short-term mood improvements following individual bouts of exercise.

CONCLUSIONS

Specific improvements in long-term mood state and short-term mood responses following individual exercise sessions were observed in these individuals with TBI. The largest improvement in overall mood was observed at 12 weeks of exercise training, with improvements emerging as early as 4 weeks into the training regimen.

Blast-Induced Tinnitus and Elevated Central Auditory and Limbic Activity in Rats: A Manganese-Enhanced MRI and Behavioral Study

Blast-induced tinitus is the number one service-connected disability that currently affects military personnel and veterans. To elucidate its underlying mechanisms, we subjected 13 Sprague Dawley adult rats to unilateral 14 psi blast exposure to induce tinnitus and measured auditory and limbic brain activity using manganese-enhanced MRI (MEMRI). Tinnitus was evaluated with a gap detection acoustic startle reflex paradigm, while hearing status was assessed with prepulse inhibition (PPI) and auditory brainstem responses (ABRs). Both anxiety and cognitive functioning were assessed using elevated plus maze and Morris water maze, respectively. Five weeks after blast exposure, 8 of the 13 blasted rats exhibited chronic tinnitus. While acoustic PPI remained intact and ABR thresholds recovered, the ABR wave P1-N1 amplitude reduction persisted in all blast-exposed rats. No differences in spatial cognition were observed, but blasted rats as a whole exhibited increased anxiety. MEMRI data revealed a bilateral increase in activity along the auditory pathway and in certain limbic regions of rats with tinnitus compared to age-matched controls. Taken together, our data suggest that while blast-induced tinnitus may play a role in auditory and limbic hyperactivity, the non-auditory effects of blast and potential traumatic brain injury may also exert an effect.

Patient navigation for traumatic brain injury promotes community re-integration and reduces re-hospitalizations

OBJECTIVE

To determine the effectiveness of a Navigation programme for patients with traumatic brain injury.

DESIGN

Prospective programme evaluation.

SETTING

Inpatient rehabilitation facility and community settings.

PARTICIPANTS

Eighteen individuals who suffered a traumatic brain injury (TBI), were between the ages of 16-70 years, and had a Rancho Score greater than IV.

INTERVENTION

Patient navigation programme focused on identifying and addressing barriers to positive outcomes, including coordination of care and facilitating communication among the family and healthcare providers, psychosocial support, caregiver support, adherence to treatment, education, community resources and financial issues.

MAIN OUTCOME MEASURES

Functional status, re-hospitalizations, falls, neurobehavioral symptom inventory, neuroendocrine status, activities of daily living, community integration and caregiver burden.

RESULTS

There was a significant reduction in re-hospitalization and fall rate when comparing individuals who received navigation services and those who did not. We also observed improved adherence treatment plans and a significant increase in community integration, independence level and functional abilities.

CONCLUSIONS

This study begins to highlight the effectiveness of a patient navigation programme for individuals with TBI. Future research with a larger sample will continue to help us refine patient navigation for chronic disabling conditions and determine its sustainability.

Improving Traumatic Brain Injury Outcomes: The Development of an Evaluation and Referral Tool at Groote Schuur Hospital

BACKGROUND

The Western Cape Province of South Africa has a great shortage of diagnostic expertise, rehabilitative infrastructure, and support services for patients with traumatic brain injury (TBI). The neurosurgical outpatient setting is busy and often chaotic, and patients are frequently lost to follow-up. This study sought to continue with the design and development of a comprehensive, yet brief tool to aid patient referrals and ensure that no consequence of TBI is left unidentified and unaddressed.

METHODS

There were 47 patients with TBI (mean age, 35 years; range, 18-75 years) assessed. The study was designed in 3 distinct phases, each representing a different stage in the tool's development.

RESULTS

The Groote Schuur Traumatic Brain Injury Evaluation was shortened and simplified. Overall, 81% of the participants indicated cognitive dysfunction. There was a high prevalence of psychological/psychiatric sequelae, with 85% of participants reporting at least 1 such problem.

CONCLUSIONS

The findings further highlight the prevalence of the cognitive, behavioral, and psychological consequences of TBI and shed additional light on the particular types of problems that patients with TBI face. Following the identified changes, the questionnaire and algorithm combination are now ready to be validated in the neurosurgical clinical setting.

Amantadine Therapy in Traumatic Brain Injury Patients

Objective:

To review literature on amantadine therapy in patients with traumatic brain injury (TBI).

Data Sources:

MEDLINE (1966–March 2006), EMBASE (1974–March 2006), BIOSIS (1969–March 2006), and International Pharmaceutical Abstracts (1970–March 2006) were searched to identify papers on the clinical outcomes of patients with TBI treated with amantadine. A bibliographic search was also performed.

Study Selection and Data Extraction:

Papers were excluded if they were not published in English, if they included patients less than 16 years old, or if they included patients in whom the effects of multiple medications, rather than amantadine alone, were studied. Reports were categorized according to the time of initiation of amantadine following the injury.

Data Synthesis:

Reports examining early initiation of amantadine suggest a possible benefit for treatment of decreased responsiveness and functional recovery. One report examining late initiation of amantadine failed to demonstrate benefit in the treatment of motor impairment, while 2 reports suggested possible improvement of functional recovery. Finally, reports examining late initiation of amantadine in the treatment of cognitive and behavioral therapy demonstrated possible benefit.

Conclusions:

Further investigation is needed before either early or late initiation of amantadine can be recommended for treatment of decreased responsiveness and functional recovery. However, while additional research is conducted, late initiation of amantadine can be considered an option for the treatment of cognitive and behavioral impairments in patients with TBI.

Efficacy of motivational interviewing and cognitive behavioral therapy for anxiety and depression symptoms following traumatic brain injury

BACKGROUND

Anxiety and depression are common following traumatic brain injury (TBI), often co-occurring. This study evaluated the efficacy of a 9-week cognitive behavioral therapy (CBT) program in reducing anxiety and depression and whether a three-session motivational interviewing (MI) preparatory intervention increased treatment response.

METHOD

A randomized parallel three-group design was employed. Following diagnosis of anxiety and/or depression using the Structured Clinical Interview for DSM-IV, 75 participants with mild-severe TBI (mean age 42.2 years, mean post-traumatic amnesia 22 days) were randomly assigned to an Adapted CBT group: (1) MI + CBT (n = 26), or (2) non-directive counseling (NDC) + CBT (n = 26); or a (3) waitlist control (WC, n = 23) group. Groups did not differ in baseline demographics, injury severity, anxiety or depression. MI and CBT interventions were guided by manuals adapted for individuals with TBI. Three CBT booster sessions were provided at week 21 to intervention groups.

RESULTS

Using intention-to-treat analyses, random-effects regressions controlling for baseline scores revealed that Adapted CBT groups (MI + CBT and NDC + CBT) showed significantly greater reduction in anxiety on the Hospital Anxiety and Depression Scale [95% confidence interval (CI) -2.07 to -0.06] and depression on the Depression Anxiety and Stress Scale (95% CI -5.61 to -0.12) (primary outcomes), and greater gains in psychosocial functioning on Sydney Psychosocial Reintegration Scale (95% CI 0.04-3.69) (secondary outcome) over 30 weeks post-baseline relative to WC. The group receiving MI + CBT did not show greater gains than the group receiving NDC + CBT.

CONCLUSIONS

Findings suggest that modified CBT with booster sessions over extended periods may alleviate anxiety and depression following TBI.

Reduced GABAergic inhibition in the basolateral amygdala and the development of anxiety-like behaviors after mild traumatic brain injury

Traumatic brain injury (TBI) is a major public health concern affecting a large number of athletes and military personnel. Individuals suffering from a TBI risk developing anxiety disorders, yet the pathophysiological alterations that result in the development of anxiety disorders have not yet been identified. One region often damaged by a TBI is the basolateral amygdala (BLA); hyperactivity within the BLA is associated with increased expression of anxiety and fear, yet the functional alterations that lead to BLA hyperexcitability after TBI have not been identified. We assessed the functional alterations in inhibitory synaptic transmission in the BLA and one mechanism that modulates excitatory synaptic transmission, the α7 containing nicotinic acetylcholine receptor (α7-nAChR), after mTBI, to shed light on the mechanisms that contribute to increased anxiety-like behaviors. Seven and 30 days after a mild controlled cortical impact (CCI) injury, animals displayed significantly greater anxiety-like behavior. This was associated with a significant loss of GABAergic interneurons and significant reductions in the frequency and amplitude of spontaneous and miniature GABAA-receptor mediated inhibitory postsynaptic currents (IPSCs). Decreases in the mIPSC amplitude were associated with reduced surface expression of α1, β2, and γ2 GABAA receptor subunits. However, significant increases in the surface expression and current mediated by α7-nAChR, were observed, signifying increases in the excitability of principal neurons within the BLA. These results suggest that mTBI causes not only a significant reduction in inhibition in the BLA, but also an increase in neuronal excitability, which may contribute to hyperexcitability and the development of anxiety disorders.

Glibenclamide for the treatment of acute CNS injury

First introduced into clinical practice in 1969, glibenclamide (US adopted name, glyburide) is known best for its use in the treatment of diabetes mellitus type 2, where it is used to promote the release of insulin by blocking pancreatic K_ATP [sulfonylurea receptor 1 (Sur1)-Kir6.2] channels. During the last decade, glibenclamide has received renewed attention due to its pleiotropic protective effects in acute CNS injury. Acting via inhibition of the recently characterized Sur1-Trpm4 channel (formerly, the Sur1-regulated NC_Ca-ATP channel) and, in some cases, via brain K_ATP channels, glibenclamide has been shown to be beneficial in several clinically relevant rodent models of ischemic and hemorrhagic stroke, traumatic brain injury, spinal cord injury, neonatal encephalopathy of prematurity, and metastatic brain tumor. Glibenclamide acts on microvessels to reduce edema formation and secondary hemorrhage, it inhibits necrotic cell death, it exerts potent anti-inflammatory effects and it promotes neurogenesis—all via inhibition of Sur1. Two clinical trials, one in TBI and one in stroke, currently are underway. These recent findings, which implicate Sur1 in a number of acute pathological conditions involving the CNS, present new opportunities to use glibenclamide, a well-known, safe pharmaceutical agent, for medical conditions that heretofore had few or no treatment options.

17β-estradiol confers protection after traumatic brain injury in the rat and involves activation of G protein-coupled estrogen receptor 1

Abstract Traumatic brain injury (TBI) is a significant public health problem in the United States. Despite preclinical success of various drugs, to date all clinical trials investigating potential therapeutics have failed. Recently, sex steroid hormones have sparked interest as possible neuroprotective agents after traumatic injury. One of these is 17β-estradiol (E2), the most abundant and potent endogenous vertebrate estrogen. The goal of our study was to investigate the acute potential protective effects of E2 or the specific G protein-coupled estrogen receptor 1 (GPER) agonist G-1 when administered in an intravenous bolus dose 1 hour post-injury in the lateral fluid percussion (LFP) rodent model of TBI. The results of this study show that, when assessed at 24 hours post-injury, E2 or G-1 confers protection in adult male rats subjected to LFP brain injury. Specifically, we found that an acute bolus dose of E2 or G-1 administered intravenously 1 hour post-TBI significantly increases neuronal survival in the ipsilateral CA 2/3 region of the hippocampus and decreases neuronal degeneration and apoptotic cell death in both the ipsilateral cortex and CA 2/3 region of the hippocampus. We also report a significant reduction in astrogliosis in the ipsilateral cortex, hilus, and CA 2/3 region of the hippocampus. Finally, these effects were observed to be chiefly dose-dependent for E2, with the 5 mg/kg dose generating a more robust level of protection. Our findings further elucidate estrogenic compounds as a clinically relevant pharmacotherapeutic strategy for treatment of secondary injury following TBI, and intriguingly, reveal a novel potential therapeutic target in GPER.

Patient Characterization Protocols for Psychophysiological Studies of Traumatic Brain Injury and Post-TBI Psychiatric Disorders

Psychophysiological investigations of traumatic brain injury (TBI) are being conducted for several reasons, including the objective of learning more about the underlying physiological mechanisms of the pathological processes that can be initiated by a head injury. Additional goals include the development of objective physiologically based measures that can be used to monitor the response to treatment and to identify minimally symptomatic individuals who are at risk of delayed-onset neuropsychiatric disorders following injury. Research programs studying TBI search for relationships between psychophysiological measures, particularly ERP (event-related potential) component properties (e.g., timing, amplitude, scalp distribution), and a participant's clinical condition. Moreover, the complex relationships between brain injury and psychiatric disorders are receiving increased research attention, and ERP technologies are making contributions to this effort. This review has two objectives supporting such research efforts. The first is to review evidence indicating that TBI is a significant risk factor for post-injury neuropsychiatric disorders. The second objective is to introduce ERP researchers who are not familiar with neuropsychiatric assessment to the instruments that are available for characterizing TBI, post-concussion syndrome, and psychiatric disorders. Specific recommendations within this very large literature are made. We have proceeded on the assumption that, as is typically the case in an ERP laboratory, the investigators are not clinically qualified and that they will not have access to participant medical records.

Mouse brain PSA-NCAM levels are altered by graded-controlled cortical impact injury

Traumatic brain injury (TBI) is a worldwide endemic that results in unacceptably high morbidity and mortality. Secondary injury processes following primary injury are composed of intricate interactions between assorted molecules that ultimately dictate the degree of longer-term neurological deficits. One comparatively unexplored molecule that may contribute to exacerbation of injury or enhancement of recovery is the posttranslationally modified polysialic acid form of neural cell adhesion molecule, PSA-NCAM. This molecule is a critical modulator of central nervous system plasticity and reorganization after injury. In this study, we used controlled cortical impact (CCI) to produce moderate or severe TBI in the mouse. Immunoblotting and immunohistochemical analysis were used to track the early (2, 24, and 48 hour) and late (1 and 3 week) time course and location of changes in the levels of PSA-NCAM after TBI. Variable and heterogeneous short- and long-term increases or decreases in expression were found. In general, alterations in PSA-NCAM levels were seen in the cerebral cortex immediately after injury, and these reductions persisted in brain regions distal to the primary injury site, especially after severe injury. This information provides a starting point to dissect the role of PSA-NCAM in TBI-related pathology and recovery.

Glibenclamide reduces hippocampal injury and preserves rapid spatial learning in a model of traumatic brain injury

Cognitive disturbances after traumatic brain injury (TBI) are frequent, even when neuroimaging shows no overt hemorrhagic or other abnormality. Sulfonylurea receptor 1 (SUR1) plays a key role in various forms of CNS injury, but its role in hippocampal dysfunction after mild to moderate TBI is unknown. To assess the hypothesis that postinjury SUR1 upregulation in the hippocampus is associated with a later disturbance in learning, we studied a rat model of cortical impact TBI calibrated to avoid primary and secondary hemorrhage in the underlying hippocampus. The transcription factor, specificity protein 1, which regulates expression of SUR1 and caspase-3, was activated in the hippocampus 15 minutes after injury. Upregulation of SUR1 protein and of Abcc8 (which encodes SUR1) messenger RNA was evident by 6 hours. To assess the role of SUR1, injured rats were administered vehicle or a low dose of the specific sulfonylurea inhibitor glibenclamide for 1 week. At 2 weeks, the increase in activated caspase-3 in the hilus of glibenclamide-treated rats was half of that in vehicle-treated rats. Testing for rapid learning in a Morris water maze at 4 weeks showed significantly better performance in glibenclamide-treated rats; performance inversely correlated with Fluoro-Jade staining for degenerated neurons in the hilus. We conclude that glibenclamide may have long-term protective effects on the hippocampus after mild-to-moderate TBI.

The effects of neuroimaging and brain injury on insanity defenses

Although neurological evidence is used with increasing frequency in criminal trials, there is limited research examining the effects that this evidence has on juror decision-making in insanity trials. Participants (396) were presented with a case summary and psychological testimony and asked to render either a verdict of guilty or not guilty by reason of insanity in a 2 (psychosis or psychopathy) x (presence or absence of an MRI indicating a brain lesion) x (presence or absence of testimony describing a car accident that caused injury to the brain) factorial design. Defendants diagnosed with a psychotic disorder, defendants who could demonstrate the existence of a brain lesion via MRI, and defendants who had a history of brain injury were more likely to be found not guilty by reason of insanity than those defendants who did not present any neurological testimony. Participants who reported they were more influenced by the psychological and neurological testimony were almost six times more likely to render a verdict of NGRI than those participants who reported that the psychological and neurological testimony and evidence did not influence their decision regarding verdict.

COG1410, a novel apolipoprotein E-based peptide, improves functional recovery in a murine model of traumatic brain injury

Traumatic brain injury (TBI) is a silent epidemic affecting approximately 1.4 million Americans annually, at an estimated annual cost of $60 billion in the United States alone. Despite an increased understanding of the pathophysiology of closed head injury, there remains no pharmacological intervention proven to improve functional outcomes in this setting. Currently, the existing standard of care for TBI consists primarily of supportive measures. Apolipoprotein E (apoE) is the primary apolipoprotein synthesized in the brain in response to injury, where it modulates several components of the neuroinflammatory cascade associated with TBI. We have previously demonstrated that COG133, an apoE mimetic peptide, improved functional outcomes and attenuated neuronal death when administered as a single intravenous injection at 30 min post-TBI in mice. Using the principles of rational drug design, we developed a more potent analog, COG1410, which expands the therapeutic window for the treatment of TBI by a factor of four, from 30 min to 2 h. Mice that received a single intravenous injection of COG1410 at 120 min post-TBI exhibited significant improvement on a short term test of vestibulomotor function and on a long term test of spatial learning and memory. This was associated with a significant attenuation of microglial activation and neuronal death in the hippocampus, the neuroanatomical substrate for learning and memory. Rationally derived apoE mimetic peptides have been demonstrated to exert neuroprotective and anti-inflammatory effects in vitro and in clinically relevant models of brain injury. This represents a novel therapeutic strategy in the treatment of TBI.

Mild traumatic brain injury and anxiety sequelae: a review of the literature

There is scattered but significant psychological and neuropsychological evidence to suggest that mild traumatic brain injury (mild TBI) plays a notable role in the emergence and expression of anxiety. Conversely, there is also empirical evidence to indicate that anxiety may exert a pronounced impact on the prognosis and course of recovery of an individual who has sustained a mild TBI. Although the relationship between mild TBI and anxiety remains unclear, the present body of research attempts to elucidate a number of aspects regarding this topic. Overall, the mild TBI research is rife with inconsistencies concerning prevalence rates, the magnitude and implications of this issue and, in the case of PTSD, even whether certain diagnoses can exist at all. This review obviates the need for greater consistencies across studies, especially between varying disciplines, and calls for a shift from studies overly focused on categorical classification to those concerned with dimensional conceptualization.

Definition, diagnosis, and forensic implications of postconcussional syndrome

Injuries from blows to the head often are manifested only as subjective complaints. Postconcussional syndrome thus can be feigned for financial or psychological gain. The authors review the pathology of brain trauma, symptoms of postconcussional syndrome, and criteria for diagnosis. In addition to somatic deficits, psychological and cognitive problems are common. The likelihood and severity of postconcussional syndrome are greater for women. Malingering may be suspected in cases involving litigation, and tests to detect it are available. Treatment for postconcussional syndrome depends on the specific symptoms. Pharmacotherapies may be helpful, but care should be used in prescribing drugs that could produce deleterious CNS effects.

Chronic intermittent nicotine administration attenuates traumatic brain injury-induced cognitive dysfunction

Traumatic brain injury (TBI) initiates immediate and secondary neuropathological cascades that can result in persistent neurological dysfunction. Previous studies from our laboratory have shown that experimental rat brain injury causes a rapid and persistent decrease in CNS alpha7* nicotinic cholinergic receptor (nAChr) expression. The purpose of this study was to investigate whether intermittent nicotine injections could improve cognitive performance in the Morris water maze (MWM) following experimental brain injury. Adult male rats were anesthetized and subjected to a 1.5 mm controlled cortical impact (CCI) injury of the somatosensory cortex. Animals received twice daily i.p. nicotine injections for 11 days prior to CCI, 11 days following CCI or during both pre- and post-surgical intervals. MWM training was initiated 12 days post-injury. In the training phase of cognitive testing, twice-daily nicotine treatment following injury attenuated trauma-induced deficits in the distance traveled to reach the escape platform. This group of animals also had improvements in several measures of the probe test, including time spent, distance traveled and total entries into the target quadrant. TBI caused significant deficits in alpha7* nAChr expression in several regions of the hippocampus and cerebral cortex, which were largely unaffected by intermittent nicotine treatment. However, nicotine treatment up-regulated [(3)H]-epibatidine binding to non-alpha7* nAChrs, attenuating TBI-induced deficits in receptor expression in several brain regions evaluated. These results suggest that nicotine is efficacious at attenuating CCI-induced cognitive deficits in a manner independent of changes in alpha7* nAChr expression, perhaps via up-regulation of non-alpha7* nAChrs.