Differential effects of single versus multiple administrations of haloperidol and risperidone on functional outcome after experimental brain trauma

Cognitive and Motor Function Effects of Antipsychotics in Traumatic Brain Injury: A Systematic Review of Pre-Clinical Studies

Traumatic brain injury (TBI) survivors often suffer from agitated behaviors and will most likely receive pharmacological treatments. Choosing an optimal and safe treatment that will not interfere with neurological recovery remains controversial. By interfering with dopaminergic circuits, antipsychotics may impede processes important to cognitive recovery. Despite their frequent use, there have been no large randomized controlled studies of antipsychotics for the management of agitated behaviors during the acute TBI recovery period. We conducted a systematic review and meta-analysis of pre-clinical studies evaluating the effects of antipsychotics post-TBI on both cognitive and motor recovery. MEDLINE and Embase databases were searched up to August 2, 2023. Pre-clinical studies evaluating the effects of antipsychotics on cognitive and motor functions post-TBI were considered. Risk of bias was evaluated with the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) tool. We identified 15 studies including a total of 1188 rodents, mostly conducted in male Sprague-Dawley rats using cortical impact injury. The analysis revealed no consistent effect of haloperidol on motor functions, but risperidone was associated with a significant impairment in motor function on day 5 post-injury (7.05 sec; 95% confidence interval [CI]: 1.47, 12.62; I2 = 92%). Other atypical antipsychotics did not result in impaired motor function. When evaluating cognitive function, haloperidol- (23.00 sec; 95% CI: 17.42-28.59; I2 = 7%) and risperidone-treated rats (24.27 sec; 95% CI: 16.18-32.36; I2 = 0%) were consistently impaired when compared to controls. In studies evaluating atypical antipsychotics, no impairments were observed. Clinicians should avoid the regular use of haloperidol and risperidone, and future human studies should be conducted with atypical antipsychotics.

Antipsychotic Drugs: The Antithesis to Neurorehabilitation in Models of Pre-Clinical Traumatic Brain Injury

Sixty-nine million traumatic brain injuries (TBIs) are reported worldwide each year, and, of those, close to 3 million occur in the United States. In addition to neurobehavioral and cognitive deficits, TBI induces other maladaptive behaviors, such as agitation and aggression, which must be managed for safe, accurate assessment and effective treatment of the patient. The use of antipsychotic drugs (APDs) in TBI is supported by some expert guidelines, which suggests that they are an important part of the pharmacological armamentarium to be used in the management of agitation. Despite the advantages of APDs after TBI, there are significant disadvantages that may not be fully appreciated clinically during decision making because of the lack of a readily available updated compendium. Hence, the aim of this review is to integrate the existing findings and present the current state of APD use in pre-clinical models of TBI. The studies discussed were identified through PubMed and the University of Pittsburgh Library System search strategies and reveal that APDs, particularly those with dopamine2 (D2) receptor antagonism, generally impair the recovery process in rodents of both sexes and, in some instances, attenuate the potential benefits of neurorehabilitation. We believe that the compilation of findings represented by this exhaustive review of pre-clinical TBI + APD models can serve as a convenient source for guiding informed decisions by critical care clinicians and physiatrists contemplating APD use for patients exhibiting agitation.

A descriptive analysis of pharmacological management of aggression and/or agitation in patients with traumatic brain injury in a Southwest Virginia inpatient population

WHAT IS KNOWN AND OBJECTIVE

Traumatic brain injury (TBI) is a major cause of disability, and it has been associated with agitation and aggression. In a previous study, we reviewed the literature to identify evidence-based pharmacological agents for treatment of agitation in TBI. Based on the results of our previous study that summarizes the findings of several systematic reviews, the use of haloperidol and benzodiazepines is not supported by the available evidence while the use of amantadine, beta blockers, antiepileptics and methylphenidate is supported by the limited available evidence. In this study, we describe the psycho-pharmacological agents that were administered to patients with agitation and/or aggression in the context of TBI in inpatient facilities of a private, non-profit health care system in southwest Virginia. We will also compare the psycho-pharmacological agents ordered before and after psychiatric consultation.

METHODS

Adult patients who were admitted to Carilion Clinic's inpatient facilities from March 30, 2013, to March 30, 2018, had a diagnosis of TBI, and received psychiatric consultation for agitation and/or aggression were enrolled in this study. A retrospective review of electronic medical records was conducted by researchers and data were collected on the following measures: ordered psycho-pharmacological agents, frequency, dosing and duration of orders, whether each administered psycho-pharmacological agent was started before or after psychiatric consultation, and psycho-pharmacological agents prescribed upon discharge.

RESULTS AND DISCUSSION

About 68% of patients were started on benzodiazepines and/or typical antipsychotics and 23% of patients were subsequently discharged on these medication categories. Only 23% of patients were ordered to receive medications supported by the evidence such as amantadine, beta blockers or antiepileptics. The percentage of patient-days with an order to receive typical antipsychotics significantly decreased following psychiatric consultation (p = 0.0056), but the percentage of patient-days with an order to receive benzodiazepines significantly increased following psychiatric consultation (p = 0.0001). This finding remained statistically significant after excluding patients with active or unclear alcohol/benzodiazepine withdrawal (p < 0.0001).

WHAT IS NEW AND CONCLUSION

This study demonstrates the widespread use of typical antipsychotics and benzodiazepines in the management of agitation in TBI and the importance of multidisciplinary collaboration, research and education of providers to improve patient care.

Chronic unpredictable stress during adolescence protects against adult traumatic brain injury-induced affective and cognitive deficits

Pre-clinical early-life stress paradigms model early adverse events in humans. However, the long-term behavioral consequences of early-life adversities after traumatic brain injury (TBI) in adults have not been examined. In addition, endocannabinoids may protect against TBI neuropathology. Hence, the current study assessed the effects of adverse stress during adolescence on emotional and cognitive performance in rats sustaining a TBI as adults, and how cannabinoid receptor 1 (CB1) activation impacts the outcome. On postnatal days (PND) 30-60, adolescent male rats were exposed to four weeks of chronic unpredictable stress (CUS), followed by four weeks of no stress (PND 60-90), or no stress at any time (Control), and then anesthetized and provided a cortical impact of moderate severity (2.8 mm tissue deformation at 4 m/s) or sham injury. TBI and Sham rats (CUS and Control) were administered either arachidonyl-2'-chloroethylamide (ACEA; 1 mg/kg, i.p.), a CB1 receptor agonist, or vehicle (VEH; 1 mL/kg, i.p.) immediately after surgery and once daily for 7 days. Anxiety-like behavior was assessed in an open field test (OFT) and learning and memory in novel object recognition (NOR) and Morris water maze (MWM) tasks. No differences were revealed among the Sham groups in any behavioral assessment and thus the groups were pooled. In the ACEA and VEH-treated TBI groups, CUS increased exploration in the OFT, enhanced NOR focus, and decreased the time to reach the escape platform in the MWM, suggesting decreased anxiety and enhanced learning and memory relative to the Control group receiving VEH (p < 0.05). ACEA also enhanced NOR and MWM performance in the Control + TBI group (p < 0.05). These data suggest that 4 weeks of CUS provided during adolescence may provide protection against TBI acquired during adulthood and/or induce adaptive behavioral responses. Moreover, CB1 receptor agonism produces benefits after TBI independent of CUS protection.

Pharmacological Treatment of Agitation and/or Aggression in Patients With Traumatic Brain Injury: A Systematic Review of Reviews

OBJECTIVE

To systematically review the available literature on the pharmacological management of agitation and/or aggression in patients with traumatic brain injury (TBI), synthesize the available data, and provide guidelines.

DESIGN

Systematic review of systematic reviews.

MAIN MEASURES

A literature review of the following websites was performed looking for systematic reviews on the treatment of agitation and/or aggression among patients with TBI: PubMed, CINAHL, DynaMed, Health Business Elite, and EBSCO (Psychology and behavioral sciences collection). Two researchers independently assessed articles for meeting inclusion/exclusion criteria. Data were extracted on year of publication, reviewed databases, dates of coverage, search limitations, pharmacological agents of interest, and a list of all controlled studies included. The included controlled studies were then examined to determine potential reasons for any difference in recommendations.

RESULTS

The literature review led to 187 citations and 67 unique publications after removing the duplicates. Following review of the title/abstracts and full texts, a total of 11 systematic reviews were included. The systematic reviews evaluated the evidence for safety and efficacy of the following medications: amantadine, amphetamines, methylphenidate, antiepileptics, atypical and typical antipsychotics, benzodiazepines, β-blockers, and sertraline.

CONCLUSIONS

On the basis of the results of this literature review, the authors recommend avoiding benzodiazepines and haloperidol for treating agitation and/or aggression in the context of TBI. Atypical antipsychotics (olanzapine in particular) can be considered as practical alternatives for the as-needed management of agitation and/or aggression in lieu of benzodiazepines and haloperidol. Amantadine, β-blockers (propranolol and pindolol), antiepileptics, and methylphenidate can be considered for scheduled treatment of agitation and/or aggression in patients with TBI.

Challenges of Delirium Management in Patients with Traumatic Brain Injury: From Pathophysiology to Clinical Practice

Traumatic brain injury (TBI) can initiate a very complex disease of the central nervous system (CNS), starting with the primary pathology of the inciting trauma and subsequent inflammatory and CNS tissue response. Delirium has long been regarded as an almost inevitable consequence of moderate to severe TBI, but more recently has been recognized as an organ dysfunction syndrome with potentially mitigating interventions. The diagnosis of delirium is independently associated with prolonged hospitalization, increased mortality and worse cognitive outcome across critically ill populations. Investigation of the unique problems and management challenges of TBI patients is needed to reduce the burden of delirium in this population. In this narrative review, possible etiologic mechanisms behind post-traumatic delirium are discussed, including primary injury to structures mediating arousal and attention and secondary injury due to progressive inflammatory destruction of the brain parenchyma. Other potential etiologic contributors include dysregulation of neurotransmission due to intravenous sedatives, seizures, organ failure, sleep cycle disruption or other delirium risk factors. Delirium screening can be accomplished in TBI patients and the presence of delirium portends worse outcomes. There is evidence that multi-component care bundles including an analgesia-prioritized sedation algorithm, regular spontaneous awakening and breathing trials, protocolized delirium assessment, early mobility and family engagement can reduce the burden of ICU delirium. The aim of this review is to summarize the approach to delirium in TBI patients with an emphasis on pathogenesis and management. Emerging CNS-active drug therapies that show promise in preclinical studies are highlighted.

The neuroprotective effect of quetiapine in critically ill traumatic brain injury patients

INTRODUCTION

Quetiapine is an atypical antipsychotic commonly used in critical care. Cellular and animal models demonstrated its novel anti-inflammatory properties in traumatic brain injury (TBI). Our study aimed to assess the effect of quetiapine on outcomes in critically ill TBI patients. We hypothesize that quetiapine improves neurological outcomes.

METHODS

The Multiparameter Intelligent Monitoring in Intensive Care database was queried, and all adult (age, ≥18 years) isolated TBI patients (extracranial Abbreviated Injury Scale, < 2) admitted to the intensive care unit for a period of >48 hours. Patients were stratified into quetiapine (+) and no-quetiapine (-) groups. Propensity score matching was performed (1:2 ratio). Outcome measures were intensive care unit length of stay, discharge Glasgow Coma Scale (GCS), and mortality. A subanalysis was performed for patients who underwent intracranial pressure (ICP) monitoring to ascertain the effect of quetiapine dose on ICP, and cerebral perfusion pressure (CPP). Survival curves and regression analyses were performed.

RESULTS

A matched cohort of (quetiapine, 116 vs. no-quetiapine, 232) patients was obtained. Mean ± SD age was 65 ± 21 years, median head Abbreviated Injury Scale was 3 (3-4), and median GCS was 10 (9-16). The median quetiapine dose given was 50 (25-125) mg. Patients who received quetiapine had lower mortality (17.2% vs. 27.6%; p = 0.03) and a higher median GCS at discharge (12 [11-14] vs. 11 [10-13]; p < 0.04) but no difference in intensive care unit length of stay (4.1 days vs. 4.7 days; p = 0.75) or discharge to skilled nursing facility (34.5% vs. 31.9%; p = 0.63). On subanalysis of patients who received quetiapine, 40% had ICP monitoring. Higher doses of quetiapine were independently associated with progressively lower ICP (β = -0.022 mm Hg/mg of quetiapine; p = 0.01) and higher CPP (β = 0.031 mm Hg/mg quetiapine; p = 0.01).

CONCLUSION

Quetiapine may decrease mortality and improve neurological outcomes in critically ill TBI patients. It has a dose-dependent effect to decrease ICP and increase CPP. Quetiapine may be a potential therapeutic modality in critically ill TBI patients, but further studies are required to explore these mechanisms.

LEVEL OF EVIDENCE

Systematic Review, level III.

Risperidone versus placebo for aggression following traumatic brain injury: a feasibility randomised controlled trial

OBJECTIVES

To conduct a feasibility randomised controlled trial of risperidone for the treatment of aggression in adults with traumatic brain injury (TBI).

DESIGN

Multicentre, parallel design, placebo controlled (1:1 ratio) double-blind feasibility trial with an embedded process evaluation. No statistical comparison was performed between the two study groups.

SETTING

Four neuropsychiatric and neurology outpatient clinics in London and Kent, UK.

PARTICIPANTS

Our aim was to recruit 50 patients with TBI over 18 months. Follow-up participants at 12 weeks using a battery of assessment scales to measure changes in aggressive behaviour and irritability (Modified Overt Aggression Scale (MOAS)-primary outcome, Irritability Questionnaire) as well as global functioning (Glasgow Outcome Scale-Extended, Clinical Global impression) and quality of life (EQ-5D-5L, SF-12), mental health (Hospital Anxiety and Depression Scale) and medication adverse effects (Udvalg for Kliniske Undersøgelser).

RESULTS

Six participants were randomised to the active arm of the trial and eight to the placebo arm over a 10-month period (28% of our target). Two participants withdrew because of adverse events. Twelve out of 14 (85.7%) patients completed a follow-up assessment at 12 weeks. At follow-up, the scores of all outcome measures improved in both groups. Placebo group showed numerically better score change according to the primary outcome MOAS. No severe adverse events were reported. The overall rate of adverse events remained low. Data from the process evaluation suggest that existence of specialised TBI follow-up clinics, availability of a dedicated database of TBI patients' clinical details, simple study procedures and regular support to participants would enhance recruitment and retention in the trial. Feedback from participants showed that once in the study, they did not find the trial procedure onerous.

CONCLUSIONS

It was not feasible to conduct a successful randomised trial of risperidone versus placebo for post-TBI aggression using the methods we deployed in this study. It is not possible to draw any definitive conclusion about risperidone's efficacy from such a small trial.

TRIAL REGISTRATION NUMBER

ISRCTN30191436.

Executive (dys)function after traumatic brain injury: special considerations for behavioral pharmacology

Executive function is an umbrella term that includes cognitive processes such as decision-making, impulse control, attention, behavioral flexibility, and working memory. Each of these processes depends largely upon monoaminergic (dopaminergic, serotonergic, and noradrenergic) neurotransmission in the frontal cortex, striatum, and hippocampus, among other brain areas. Traumatic brain injury (TBI) induces disruptions in monoaminergic signaling along several steps in the neurotransmission process - synthesis, distribution, and breakdown - and in turn, produces long-lasting deficits in several executive function domains. Understanding how TBI alters monoamingeric neurotransmission and executive function will advance basic knowledge of the underlying principles that govern executive function and potentially further treatment of cognitive deficits following such injury. In this review, we examine the influence of TBI on the following measures of executive function - impulsivity, behavioral flexibility, and working memory. We also describe monoaminergic-systems changes following TBI. Given that TBI patients experience alterations in monoaminergic signaling following injury, they may represent a unique population with regard to pharmacotherapy. We conclude this review by discussing some considerations for pharmacotherapy in the field of TBI.

Pharmacological interventions for agitated behaviours in patients with traumatic brain injury: a systematic review

OBJECTIVE

The aim of this systematic review was to assess the efficacy and safety of pharmacological agents in the management of agitated behaviours following traumatic brain injury (TBI).

METHODS

We performed a search strategy in PubMed, OvidMEDLINE, Embase, CINAHL, PsycINFO, Cochrane Library, Google Scholar, Directory of Open Access Journals, LILACS, Web of Science and Prospero (up to 10 December 2018) for published and unpublished evidence on the risks and benefits of 9 prespecified medications classes used to control agitated behaviours following TBI. We included all randomised controlled trials, quasi-experimental and observational studies examining the effects of medications administered to control agitated behaviours in TBI patients. Included studies were classified into three mutually exclusive categories: (1) agitated behaviour was the presenting symptom; (2) agitated behaviour was not the presenting symptom, but was measured as an outcome variable; and (3) safety of pharmacological interventions administered to control agitated behaviours was measured.

RESULTS

Among the 181 articles assessed for eligibility, 21 studies were included. Of the studies suggesting possible benefits, propranolol reduced maximum intensities of agitation per week and physical restraint use, methylphenidate improved anger measures following 6 weeks of treatment, valproic acid reduced weekly agitated behaviour scale ratings and olanzapine reduced irritability, aggressiveness and insomnia between weeks 1 and 3 of treatment. Amantadine showed variable effects and may increase the risk of agitation in the critically ill. In three studies evaluating safety outcomes, antipsychotics were associated with an increased duration of post-traumatic amnesia (PTA) in unadjusted analyses. Small sample sizes, heterogeneity and an unclear risk of bias were limits.

CONCLUSIONS

Propranolol, methylphenidate, valproic acid and olanzapine may offer some benefit; however, they need to be further studied. Antipsychotics may increase the length of PTA. More studies on tailored interventions and continuous evaluation of safety and efficacy throughout acute, rehabilitation and outpatient settings are needed.

PROSPERO REGISTRATION NUMBER

CRD42016033140.

Environmental enrichment and amantadine confer individual but nonadditive enhancements in motor and spatial learning after controlled cortical impact injury

Environmental enrichment (EE) and amantadine (AMT) enhance motor and cognitive outcome after experimental traumatic brain injury (TBI). However, there are no data on the effects of combining these two therapies. Hence, the aim of the current study was to combine EE and AMT after TBI to determine if their net effect further enhances motor and cognitive performance. Anesthetized adult male rats received either a cortical impact of moderate severity or sham injury and then were randomly assigned to EE or standard (STD) housing and once daily administration of AMT (20 mg/kg; i.p.) or saline vehicle (VEH, 1 mL/kg; i.p.) beginning 24 h after injury for 19 days. Motor and cognitive function were assessed on post-surgical days 1-5 and 14-19, respectively. Cortical lesion volume was quantified on day 21. There were no statistical differences among the sham groups regardless of therapy, so the data were pooled. EE, AMT, and their combination (EE + AMT) improved beam-balance, but only EE and EE + AMT enhanced beam-walking. All three treatment paradigms improved spatial learning and memory relative to the VEH-treated STD controls (p < 0.05). No differences were revealed between the EE groups, regardless of treatment, but both were better than the AMT-treated STD group on beam-walking and spatial learning (p < 0.05). Both EE groups equally reduced cortical lesion volume relative to the STD-housed AMT and VEH groups (p < 0.05). The results indicate that although beneficial on their own, EE + AMT do not provide additional benefits after TBI. It is important to note that the lack of additive effects using the current treatment and behavioral protocols does not detract from the benefits of each individual therapy. The findings provide insight for future combination studies.

Aripiprazole and environmental enrichment independently improve functional outcome after cortical impact injury in adult male rats, but their combination does not yield additional benefits

Typical antipsychotic drugs (APDs) with D₂antagonistic properties impede functional outcome after experimental traumatic brain injury (TBI) and reduce the effectiveness of environmental enrichment (EE). Here we test the hypothesis that aripiprazole (ARIP), an atypical APD with partial D₂and 5-HT_1Areceptor agonist activities will improve recovery after TBI and when combined with EE will further enhance the benefits. Anesthetized adult male rats received either a controlled cortical impact of moderate severity or sham injury and then were randomly assigned to EE or standard (STD) housing and once daily intraperitoneal injections of ARIP (0.1 mg/kg) or vehicle (VEH; 1.0 mL/kg) beginning 24 h after injury for 19 days. Motor (beam-walking time and beam-walk score) and cognitive (acquisition of spatial learning and memory) outcomes were assessed on post-operative days 1-5 and 14-19, respectively. Cortical lesion volume was quantified on day 21. There were no statistical differences among the sham groups, regardless of housing or treatment, so the data were pooled. The SHAM group performed better than all TBI groups on motor and spatial learning (p < 0.05) but did not differ from either EE group on memory retention. Regarding TBI, both EE groups improved motor and cognitive outcomes vs. the VEH-treated STD group (p < 0.05) but did not differ from one another (p > 0.05). The ARIP-treated STD group performed better than the VEH-treated STD group on beam-walk score and spatial learning (p < 0.05), but not beam-walking time or memory retention (p > 0.05). Cortical lesion volume was smaller in all treated groups compared to the TBI + STD + VEH group (p < 0.05). The data replicate previous work and extend the findings by demonstrating that 1) ARIP promotes recovery after TBI, but combining treatments does not yield additional benefits, which is contrary to the hypothesis, and 2) unlike APDs that exhibit D₂ receptor antagonism, ARIP does not impede rehabilitation (i.e., EE).

Intermittent Administration of Haloperidol after Cortical Impact Injury Neither Impedes Spontaneous Recovery Nor Attenuates the Efficacy of Environmental Enrichment

The administration of haloperidol (HAL) once-daily for 19 days after experimental traumatic brain injury (TBI) impedes recovery and attenuates the efficacy of environmental enrichment (EE). However, it is unknown how intermittent administration of HAL affects the recovery process when paired with EE. Addressing the uncertainty is relevant because daily HAL is not always warranted to manage TBI-induced agitation in the clinic, and indeed intermittent therapy may be a more common approach. Hence, the aim of the study was to test the hypothesis that intermittent HAL would neither impair recovery in standard (STD)-housed controls nor attenuate the efficacy of EE. Anesthetized adult male rats received a cortical impact or sham injury and then were housed in STD or EE conditions. Beginning 24 h later, HAL (0.5 mg/kg; intraperitoneally [i.p.]) was administered either once-daily for 19 days or once every other day, whereas vehicle (VEH; 1 mL/kg; i.p.) was administered once daily. Motor performance and cognition were assessed on post-injury days 1-5 and 14-19, respectively. Cortical lesion volume was quantified on day 21. SHAM controls performed better than all TBI groups on motor and spatial learning [p < 0.05], but did not differ from the TBI + EE + daily VEH group on memory retention [p > 0.05]. The TBI + EE + daily VEH and TBI + EE + intermittent HAL groups did not differ from one another on beam-walk or spatial learning [p > 0.05], and both performed better than all other TBI groups [p < 0.05]. In contrast, the TBI + STD + daily HAL group performed worse than all TBI groups on spatial learning [p < 0.05]. No difference in any endpoint was revealed between the TBI + STD + intermittent HAL and TBI + STD + daily VEH groups [p > 0.05]. The results support the hypothesis that HAL is not detrimental when provided intermittently. If translatable to the clinic, intermittent HAL may be used to control TBI-induced agitation without negatively affecting spontaneous recovery or rehabilitative efficacy.

Aggression Following Traumatic brain injury: Effectiveness of Risperidone (AFTER): study protocol for a feasibility randomised controlled trial

BACKGROUND

Traumatic brain injury (TBI) is a major public health concern and many people develop long-lasting physical and neuropsychiatric consequences following a TBI. Despite the emphasis on physical rehabilitation, it is the emotional and behavioural consequences that have greater impact on people with TBI and their families. One such problem behaviour is aggression which can be directed towards others, towards property or towards the self. Aggression is reported to be common after TBI (37-71%) and causes major stress for patients and their families. Both drug and non-drug interventions are used to manage this challenging behaviour, but the evidence-base for these interventions is poor and no drugs are currently licensed for the treatment of aggression following TBI. The most commonly used drugs for this purpose are antipsychotics, particularly second-generation drugs such as risperidone. Despite this widespread use, randomised controlled trials (RCTs) of antipsychotic drugs, including risperidone, have not been conducted. We have, therefore, set out to test the feasibility of conducting an RCT of this drug for people who have aggressive behaviour following TBI.

METHODS/DESIGN

We will examine the feasibility of conducting a placebo-controlled, double-blind RCT of risperidone for the management of aggression in adults with TBI and also assess participants' views about their experience of taking part in the study. We will randomise 50 TBI patients from secondary care services in four centres in London and Kent to up to 4 mg of risperidone orally or an inert placebo and follow them up 12 weeks later. Participants will be randomised to active or control treatment in a 1:1 ratio via an external and remote web-based randomisation service. Participants will be assessed at baseline and 12-week follow-up using a battery of assessment scales to measure changes in aggressive behaviour (MOAS, IRQ) as well as global functioning (GOS-E, CGI), quality of life (EQ-5D-5L, SF-12) and mental health (HADS). We will also assess the adverse effect profile with a standard scale (UKU) and collect available data from medical records on blood tests (serum glucose/HbA1c, lipid profile, prolactin), and check body weight and blood pressure. In addition completion of the MOAS and a check for any new or worsening side-effect will be completed weekly and used by the prescribing clinician to determine continuing dosage. Family carers' wellbeing will be assessed with CWSQ. Service use will be recorded using CSRI. A process evaluation will be carried out at the end of the trial using both qualitative and quantitative methodology.

DISCUSSION

Aggressive behaviour causes immense distress among some people with TBI and their families. By examining the feasibility of a double-blind, placebo-controlled RCT, we aim to discover whether this approach can successfully be used to test the effects of risperidone for the treatment of aggressive behaviour among people with aggression following TBI and improve the evidence base for the treatment of these symptoms. Our criteria for demonstrating success of the feasibility study are: (1) recruitment of at least 80% of the study sample, (2) uptake of intervention by at least 80% of participants in the active arm of the trial and (3) completion of follow-up interviews at 12 weeks by at least 75% of the study participants.

TRIAL REGISTRATION

ISRCTN30191436 . Registered on 19 December 2016.

Spontaneous recovery after controlled cortical impact injury is not impeded by intermittent administration of the antipsychotic drug risperidone

Several preclinical studies have reported that daily administration of the antipsychotic drug (APD) risperidone (RISP) impedes recovery after traumatic brain injury (TBI). However, it is not known whether intermittent dosing would produce similar deleterious effects. The relevance of providing APDs intermittently is that not all patients in rehabilitation require daily treatments to manage TBI-induced agitation. Hence, the goal of the current study was to test the hypothesis that intermittent (vs. daily) administration of RISP would be less disturbing to motor and cognitive recovery after TBI. Anesthetized adult male rats were subjected to either a cortical impact of moderate severity or sham injury and then were randomly assigned to groups receiving intraperitoneal injections of vehicle (VEH; 1.0 mL/kg) or RISP (0.45 mg/kg) 1x, 3x, or 7x per week until the completion of behavioral testing, which consisted of motor and cognitive assessments on post-operative days 1-5 and 14-19, respectively. The group receiving RISP 7x week exhibited greater motor and cognitive impairment compared to those receiving RISP 1x or 3x per week, or VEH [p<0.05]. Moreover, no differences were observed between the intermittent RISP groups vs. VEH [p>0.05], which supports the hypothesis. A potential clinical ramification is that RISP may be safe to manage agitation after TBI, but only when used sparingly.

Environmental enrichment, alone or in combination with various pharmacotherapies, confers marked benefits after traumatic brain injury

Traumatic brain injury (TBI) is a significant health care issue that affects over ten million people worldwide. Treatment options are limited with numerous failures resulting from single therapies. Fortunately, several preclinical studies have shown that combination treatment strategies may afford greater improvement and perhaps can lead to successful clinical translation, particularly if one of the therapies is neurorehabilitation. The aim of this review is to highlight TBI studies that combined environmental enrichment (EE), a preclinical model of neurorehabilitation, with pharmacotherapies. A series of PubMed search strategies yielded only nine papers that fit the criteria. The consensus is that EE provides robust neurobehavioral, cognitive, and histological improvement after experimental TBI and that the combination of EE with some pharmacotherapies can lead to benefits beyond those revealed by single therapies. However, it is noted that EE can be challenged by drugs such as the acetylcholinesterase inhibitor, donepezil, and the antipsychotic drug, haloperidol, which attenuate its efficacy. These findings may help shape clinical neurorehabilitation strategies to more effectively improve patient outcome. Potential mechanisms for the EE and pharmacotherapy-induced effects are also discussed. This article is part of the Special Issue entitled "Neurobiology of Environmental Enrichment".

Elucidating opportunities and pitfalls in the treatment of experimental traumatic brain injury to optimize and facilitate clinical translation

The aim of this review is to discuss the research presented in a symposium entitled "Current progress in characterizing therapeutic strategies and challenges in experimental CNS injury" which was presented at the 2016 International Behavioral Neuroscience Society annual meeting. Herein we discuss diffuse and focal traumatic brain injury (TBI) and ensuing chronic behavioral deficits as well as potential rehabilitative approaches. We also discuss the effects of stress on executive function after TBI as well as the response of the endocrine system and regulatory feedback mechanisms. The role of the endocannabinoids after CNS injury is also discussed. Finally, we conclude with a discussion of antipsychotic and antiepileptic drugs, which are provided to control TBI-induced agitation and seizures, respectively. The review consists predominantly of published data.

Spontaneous recovery of traumatic brain injury-induced functional deficits is not hindered by daily administration of lorazepam

Agitation and aggression are common sequelae of traumatic brain injury (TBI) and pose a challenge to physicians and other health providers during acute patient care and subsequent neurorehabilitation. Antipsychotic drugs (APDs) are routinely administered to manage TBI patients displaying such maladaptive behaviors despite several clinical and preclinical studies demonstrating that they hinder recovery. A potentially viable alternative to APDs may be the benzodiazepines, which have differing mechanisms of action. Hence, the aim of the study was to test the hypothesis that lorazepam (LOR) would not impede recovery after TBI. Anesthetized adult male rats received a cortical impact or sham injury and then were intraperitoneally administered LOR (0.1mg/kg, 1.0mg/kg, or 2.0mg/kg) or vehicle (VEH; 1mL/kg) commencing 24-h after surgery and once daily for 19days. Motor and cognitive outcomes were assessed on post-operative days 1-5 and 14-19, respectively. No differences were revealed among the four sham control groups and thus they were pooled into one inclusive SHAM group. The SHAMs performed better than all TBI groups on all assessments (p<0.05). Regarding TBI, the 2.0mg/kg LOR group performed better than the VEH and 0.1mg/kg or 1.0mg/kg LOR groups on every task (p<0.05); no differences were observed among the latter three groups on any endpoint (p>0.05). Overall, these preclinical behavioral data support the hypothesis and reveal a therapeutic benefit with the higher dose of LOR. The findings suggest that LOR may be an alternative, to APDs, for controlling agitation without compromising spontaneous recovery and perhaps could afford a dual benefit by also promoting therapeutic efficacy.

Comparable impediment of cognitive function in female and male rats subsequent to daily administration of haloperidol after traumatic brain injury

Antipsychotic drugs, such as haloperidol (HAL), are prescribed in the clinic to manage traumatic brain injury (TBI)-induced agitation. While preclinical studies have consistently shown that once-daily administration of HAL hinders functional recovery after TBI in male rats, its effects in females are unknown. Hence, the objective of this study was to directly compare neurobehavioral and histological outcomes in both sexes to determine whether the reported deleterious effects of HAL extend to females. Anesthetized adult female and male rats received either a controlled cortical impact (CCI) or sham injury and then were randomly assigned to a dosing regimen of HAL (0.5mg/kg, i.p.) or vehicle (VEH; 1mL/kg, i.p.) that was initiated 24h after injury and continued once daily for 19 consecutive days. Motor function was tested using established beam-balance/walk protocols on post-operative days 1-5 and acquisition of spatial learning was assessed with a well-validated Morris water maze task on days 14-19. Cortical lesion volume was quantified at 21days. No statistical differences were revealed between the HAL and VEH-treated sham groups and thus they were pooled for each sex. HAL only impaired motor recovery in males (p<0.05), but significantly diminished spatial learning in both sexes (p<0.05). Females, regardless of treatment, exhibited smaller cortical lesions vs VEH-treated males (p<0.05). Taken together, the data show that daily HAL does not prohibit motor recovery in females, but does negatively impact cognition. These task-dependent differential effects of HAL in female vs male rats may have clinical significance as they can direct therapy.

Pharmacological interventions for agitation in patients with traumatic brain injury: protocol for a systematic review and meta-analysis

BACKGROUND

Traumatic brain injury (TBI) is a worldwide leading cause of mortality and disability. Among TBI complications, agitation is a frequent behavioural problem. Agitation causes potential harm to patients and caregivers, interferes with treatments, leads to unnecessary chemical and physical restraints, increases hospital length of stay, delays rehabilitation, and impedes functional independence. Pharmacological treatments are often considered for agitation management following TBI. Several types of agents have been proposed for the treatment of agitation. However, the benefit and safety of these agents in TBI patients as well as their differential effects and interactions are uncertain. In addition, animal studies and observational studies have suggested impaired cognitive function with the use of certain antipsychotics and benzodiazepines. Hence, a safe and effective treatment for agitation, which does not interfere with neurological recovery, remains to be identified.

METHODS/DESIGN

With the help of Health Sciences librarian, we will design a search strategy in the following databases: PubMed, Ovid MEDLINE®, EMBASE, CINAHL, PsycINFO, Cochrane Library, Google Scholar, Directory of Open Access Journals, LILACS, Web of Science, and Prospero. A grey literature search will be performed using the resources suggested in CADTH's Grey Matters. We will include all randomized controlled, quasi-experimental, and observational studies with control groups. The population of interest is all patients, including children and adults, who have suffered a TBI. We will include studies in which agitation, not further defined, was the presenting symptom or one of the presenting symptoms. We will also include studies where agitation was not the presenting symptom but was measured as an outcome variable and studies assessing the safety of these pharmacological interventions in TBI patients. We will include studies evaluating all pharmacological interventions including beta-adrenergic blockers, typical and atypical antipsychotics, anticonvulsants, dopamine agonists, psychostimulants, antidepressants, alpha-2-adrenergic agonists, hypnotics, and anxiolytics.

DISCUSSION

Although agitation is frequent following TBI and pharmacological agents that are often used, there is no consensus on the most efficacious and safest strategy to treat these complications. There is a need for an updated systematic review to summarize the evidence in order to inform practice and future research.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016033140.

Intermittent treatment with haloperidol or quetiapine does not disrupt motor and cognitive recovery after experimental brain trauma

Traumatic brain injury (TBI)-induced agitation and aggression pose major obstacles to clinicians in the acute hospital and rehabilitation settings. Thus, management of these symptoms is crucial. Antipsychotic drugs (APDs) are a common treatment approach for alleviating these symptoms. However, previous preclinical TBI studies have indicated that daily and chronic administration of these drugs (e.g., haloperidol; HAL) can exacerbate cognitive and motor deficits. Quetiapine (QUE) is an atypical APD that differs from many typical APDs, such as HAL, in its relatively rapid dissociation from the D₂ receptor. The goal of this study was to test the hypotheses that intermittent HAL and QUE would not hinder recovery of cognitive and motor function following TBI and that daily QUE would also not impair functional recovery, which would be in contrast to HAL. Seventy anesthetized male rats received either a controlled cortical impact or sham injury and were then randomly assigned to TBI and sham groups receiving HAL (0.5mg/kg) or QUE (10mg/kg) intraperitoneally once per day or once every other day and compared to each other and vehicle (VEH) controls. Motor function was assessed by beam balance/walk tests on post-operative days 1-5 and cognitive function was evaluated with a Morris water maze task on days 14-19. No differences were revealed among the sham groups in any task, and hence the data were pooled. No overall differences were detected among the TBI groups, regardless of treatment or administration paradigm [p>0.05], but all were impaired vs. SHAM controls [p<0.05]. The SHAM controls also performed significantly better in the cognitive test vs. all TBI groups [p<0.05]. Moreover, the TBI+continuous HAL group performed worse than the TBI+continuous VEH, TBI+continuous QUE, and TBI+intermittent QUE groups [p<0.05], which did not differ from one another. Overall, the data suggest that QUE does not exacerbate TBI-induced cognitive and motor deficits, which supports the hypothesis. QUE may prove useful as an alternative APD treatment for management of agitation and aggression after clinical TBI. HAL may also be safe, but only if used sparingly.

Relative to Typical Antipsychotic Drugs, Aripiprazole Is a Safer Alternative for Alleviating Behavioral Disturbances After Experimental Brain Trauma

BACKGROUND

Antipsychotic drugs (APDs) are used to manage traumatic brain injury (TBI)-induced behavioral disturbances, such as agitation and aggression. However, APDs exhibiting D₂ receptor antagonism impede cognitive recovery after experimental TBI. Hence, empirical evaluation of APDs with different mechanistic actions is warranted. Aripiprazole (ARIP) is a D₂ and 5-hydroxytryptamine_1A (5-HT_1A) receptor agonist; pharmacotherapies with these properties enhance cognition after TBI.

OBJECTIVE

To test the hypothesis that ARIP would increase behavioral performance and decrease histopathology after TBI.

METHODS

Adult male rats were subjected to either a controlled cortical impact (CCI) or sham injury and then randomly assigned to ARIP (0.1 or 1.0 mg/kg) or VEH (1.0 mL/kg, saline vehicle) groups. Treatments began 24 hours after surgery and were administered once daily for 19 days. Motor (beam-balance/beam-walk) and cognitive (Morris water maze) performance was assessed on postoperative days 1 to 5 and 14 to 19, respectively, followed by quantification of hippocampal CA_1,3 neuron survival and cortical lesion volume.

RESULTS

Beam-balance was significantly improved in the CCI + ARIP (1.0 mg/kg) group versus CCI + ARIP (0.1 mg/kg) and CCI + VEH (P < .05). Spatial learning and memory retention were significantly improved in the CCI + ARIP (0.1 mg/kg) group versus the CCI + ARIP (1.0 mg/kg) and CCI + VEH groups (P < .05). Both doses of ARIP reduced lesion size and CA₃ cell loss versus VEH (P < .05). Importantly, neither dose of ARIP impeded functional recovery as previously reported with other APDs.

CONCLUSION

These findings support the hypothesis and endorse ARIP as a safer APD for alleviating behavioral disturbances after TBI.

Combination therapies for neurobehavioral and cognitive recovery after experimental traumatic brain injury: Is more better?

Traumatic brain injury (TBI) is a significant health care crisis that affects two million individuals in the United Sates alone and over ten million worldwide each year. While numerous monotherapies have been evaluated and shown to be beneficial at the bench, similar results have not translated to the clinic. One reason for the lack of successful translation may be due to the fact that TBI is a heterogeneous disease that affects multiple mechanisms, thus requiring a therapeutic approach that can act on complementary, rather than single, targets. Hence, the use of combination therapies (i.e., polytherapy) has emerged as a viable approach. Stringent criteria, such as verification of each individual treatment plus the combination, a focus on behavioral outcome, and post-injury vs. pre-injury treatments, were employed to determine which studies were appropriate for review. The selection process resulted in 37 papers that fit the specifications. The review, which is the first to comprehensively assess the effects of combination therapies on behavioral outcomes after TBI, encompasses five broad categories (inflammation, oxidative stress, neurotransmitter dysregulation, neurotrophins, and stem cells, with and without rehabilitative therapies). Overall, the findings suggest that combination therapies can be more beneficial than monotherapies as indicated by 46% of the studies exhibiting an additive or synergistic positive effect versus on 19% reporting a negative interaction. These encouraging findings serve as an impetus for continued combination studies after TBI and ultimately for the development of successful clinically relevant therapies.

Combining the Antipsychotic Drug Haloperidol and Environmental Enrichment after Traumatic Brain Injury Is a Double-Edged Sword

Environmental enrichment (EE) confers significant benefits after experimental traumatic brain injury (TBI). In contrast, the antipsychotic drug (APD) haloperidol (HAL) exerts deleterious effects on neurobehavioral and cognitive recovery. Neurorehabilitation and management of agitation, however, are integral components of the treatment strategy for patients with TBI. Hence, the goal of this study was to determine how the two therapeutic approaches interact and influence motor and cognitive recovery. Anesthetized adult male rats received a controlled cortical impact (2.8 mm tissue deformation at 4 m/sec) or sham injury and then were provided HAL (0.5 mg/kg; intraperitoneally [IP]) or vehicle (VEH; 1 mL/kg; IP) commencing 24 h after surgery and once daily for 19 days while housed in EE or standard (STD) conditions. Beam balance/walk and Morris water maze performance were assessed on post-injury days 1-5 and 14-19, respectively, followed immediately by quantification of cortical lesion volumes. The data revealed both expected and unexpected findings. It was not surprising that the TBI groups receiving EE performed significantly better than those in STD housing and that the TBI + STD + HAL group performed worse than the TBI + STD + VEH group (p < 0.05). What was surprising was that the therapeutic effects of EE were greatly reduced by concomitant administration of HAL. No differences in cortical lesion volumes were observed among the groups (p > 0.05). The potential clinical implications of these findings suggest that administering HAL to patients undergoing neurorehabilitation may be a double-edged sword because agitation must be controlled before rehabilitation can be safely initiated and executed, but its use may compromise therapeutic efficacy.

Drugs for behavior disorders after traumatic brain injury: Systematic review and expert consensus leading to French recommendations for good practice

OBJECTIVE

There are no handbook or recommendations for the use of pharmacological agents to treat neurobehavioral disorders after traumatic brain injury (TBI). This work proposes a systematic review of the literature and a user guide on neuroleptics, antidepressants, beta-blockers, mood stabilizers and other medications for irritability, aggressiveness, agitation, impulsivity, depression, apathy…

METHOD

Steering, working and reading groups (62 people) were formed under the control of the French High Authority for Health (HAS) in collaboration with the SOFMER scientific society (French Society of Physical and Rehabilitation Medicine). Articles were searched by HAS officers in the Medline database from 1990 to 2012, crossing TBI and pharmacological agents. The HAS method to select, read and analyze papers is close to the PRISMA statements.

RESULTS

Out of 772 references, 89 were analyzed, covering a total of 1306 people with TBI. There is insufficient evidence to standardize drug treatments for these disorders. There are however some elements to establish consensus recommendations for good clinical practice. Propranolol can improve aggression (B grade). Carbamazepine and valproate seem effective on agitation and aggression and are recommended as first line treatment (Expert Consensus [EC]). There is no evidence of efficacy for neuroleptics. Their prescription is based on emergency situation for a crisis (loxapine) but not for long-term use (EC). Antidepressants are recommended to treat depression (EC) with a higher standard of proof for Selective Serotonin Reuptake Inhibitors (SSRI, grade B). Other products are described.

CONCLUSION

The choice of treatment depends on the level of evidence, target symptoms, custom objectives, clinical experience and caution strategies.

5-hydroxytryptamine1A (5-HT1A) receptor agonists: A decade of empirical evidence supports their use as an efficacious therapeutic strategy for brain trauma

Traumatic brain injury (TBI) is a significant and enduring health care issue with limited treatment options. While several pre-clinical therapeutic approaches have led to enhanced motor and/or cognitive performance, the benefits of these treatments have not translated to the clinic. One plausible explanation is that the therapies may not have been rigorously evaluated, thus rendering the bench-to-bedside leap premature and subsequently unsuccessful. An approach that has undergone considerable empirical research after TBI is pharmacological targeting of 5-HT1A receptors with agonists such as repinotan HCl, 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), and buspirone. The goal of this review is to integrate and interpret the findings from a series of studies that evaluated the efficacy of 5-HT1A receptor agonists on functional, histological, and molecular outcome after acquired brain injury. The overwhelming consensus of this exhaustive review is that a decade of empirical evidence supports their use as an efficacious therapeutic strategy for brain trauma. This article is part of a Special Issue entitled SI:Brain injury and recovery.

Divergent long-term consequences of chronic treatment with haloperidol, risperidone, and bromocriptine on traumatic brain injury-induced cognitive deficits

Antipsychotic drugs (APDs) are provided in the clinic to manage traumatic brain injury (TBI)-induced agitation and aggression. Experimental TBI studies consistently show that daily administration of the APDs, haloperidol (HAL) and risperidone (RISP), hinder recovery. However, it is unknown how long the adverse effects remain after cessation of treatment. To elucidate this clinically relevant issue, anesthetized male rats were randomly assigned to four TBI (controlled cortical impact) and four sham groups administered HAL (0.5 mg/kg), RISP (0.45 mg/kg), bromocriptine (BRO; 5.0 mg/kg, included as a control for D2 receptor action), or vehicle (VEH; 1 mL/kg) 24 h after surgery and once-daily for 19 days. Motor and cognitive recovery was assessed on days 1-5 and 14-19, respectively, and again at 1 and 3 months after drug withdrawal. No overall group differences were observed for motor function among the TBI groups, although the HAL group showed a greater beam-walk deficit on day 5 versus the VEH and BRO groups. Cognitive recovery was significantly impaired in the HAL and RISP groups during the treatment phase versus VEH and BRO. Further, BRO was superior to VEH (p=0.0042). At 1 month, both groups that received APDs continued to exhibit significant cognitive impairment versus VEH and BRO; at 3 months, only the HAL group was impaired. Moreover, the HAL, RISP, and VEH groups continued to be cognitively deficient versus BRO, which also reduced cortical damage. These data replicate previous reports that HAL and RISP impede cognitive recovery after TBI and expand the literature by revealing that the deleterious effects persist for 3 months after drug discontinuation. BRO conferred cognitive benefits when administered concomitantly with behavioral testing, thus replicating previous findings, and also after cessation demonstrating enduring efficacy.

Aggression, DRD1 polymorphism, and lesion location in penetrating traumatic brain injury

OBJECTIVE

This study evaluated whether structural brain lesions modulate the relationship between pathological aggression and the dopaminergic system in traumatic brain injury (TBI). While converging evidence suggests that different areas of the prefrontal cortex modulate dopaminergic activity, to date no evidence exists of a modulation of endogenous dopaminergic tone by lesion localization in penetrating TBI (pTBI).

METHODS

This study included 141 male Caucasian veterans who suffered penetrating pTBI during their service in Vietnam and 29 healthy male Caucasian Vietnam veterans. Participants were genotyped for 3 functional single nucleotide polymorphisms (SNPs): dopamine receptor D1 (DRD1) rs686, dopamine receptor D2 (DRD2) rs4648317, and catechol-O-methyltransferase (COMT) Val158Met. Patients underwent brain CT scans and were divided into medial prefrontal cortex, lateral prefrontal cortex, and posterior cortex lesion groups. Long-term aggression levels were evaluated with the agitation/aggression subscale of the Neuropsychiatric Inventory.

RESULTS

Our data showed that carriers of more transcriptionally active DRD1 alleles compared to noncarriers demonstrated greater aggression levels due to medial prefrontal cortex lesions but reduced aggression levels due to lateral prefrontal cortex lesions independently of DRD2 rs4648317 or COMT Val158Met genotypes.

CONCLUSIONS

Our results suggest that the relationship between pTBI-related aggression and the dopaminergic system is modulated by lesion location. Potentially lesion location could represent an easy-to-use, widely available, para-clinical marker to help in the development of an individualized therapeutic approach to pTBI-related pathological aggression.

Endogenous nitric-oxide synthase inhibitor ADMA after acute brain injury

Previous results on nitric oxide (NO) metabolism after traumatic brain injury (TBI) show variations in NO availability and controversial effects of exogenous nitric oxide synthase (NOS)-inhibitors. Furthermore, elevated levels of the endogenous NOS inhibitor asymmetric dimethylarginine (ADMA) were reported in cerebro-spinal fluid (CSF) after traumatic subarachnoid hemorrhage (SAH). Therefore, we examined whether ADMA and the enzymes involved in NO- and ADMA-metabolism are expressed in brain tissue after TBI and if time-dependent changes occur. TBI was induced by controlled cortical impact injury (CCII) and neurological performance was monitored. Expression of NOS, ADMA, dimethylarginine dimethylaminohydrolases (DDAH) and protein-arginine methyltransferase 1 (PRMT1) was determined by immunostaining in different brain regions and at various time-points after CCII. ADMA and PRMT1 expression decreased in all animals after TBI compared to the control group, while DDAH1 and DDAH2 expression increased in comparison to controls. Furthermore, perilesionally ADMA is positively correlated with neuroscore performance, while DDAH1 and DDAH2 are negatively correlated. ADMA and its metabolizing enzymes show significant temporal changes after TBI and may be new targets in TBI treatment.

Emergency neurological life support: airway, ventilation, and sedation

Airway management is central to the resuscitation of the neurologically ill. These patients often have evolving processes that threaten the airway and adequate ventilation. Therefore, airway, ventilation, and sedation were chosen as an Emergency Neurological Life Support (ENLS) protocol. Reviewed topics include airway management; the decision to intubate; when and how to intubate with attention to cardiovascular status; mechanical ventilation settings; and the use of sedation, including how to select sedative agents based on the patient's neurological status.

Traumatic brain injury-induced cognitive and histological deficits are attenuated by delayed and chronic treatment with the 5-HT1A-receptor agonist buspirone

The aim of this study was to evaluate the potential efficacy of the serotonin(1A) (5-HT(1A)) receptor agonist buspirone (BUS) on behavioral and histological outcome after traumatic brain injury (TBI). Ninety-six isoflurane-anesthetized adult male rats were randomized to receive either a controlled cortical impact or sham injury, and then assigned to six TBI and six sham groups receiving one of five doses of BUS (0.01, 0.05, 0.1, 0.3, or 0.5 mg/kg) or saline vehicle (VEH, 1.0 mL/kg). Treatments began 24 h after surgery and were administered intraperitoneally once daily for 3 weeks. Motor function (beam-balance/beam-walk tests) and spatial learning/memory (Morris water maze) were assessed on post-operative days 1-5 and 14-19, respectively. Morphologically intact CA1/CA3 cells and cortical lesion volume were quantified at 3 weeks. No differences were observed among the BUS and VEH sham groups in any end-point measure and thus the data were pooled. Regarding the TBI groups, repeated-measures ANOVAs revealed that the 0.3 mg/kg dose of BUS enhanced cognitive performance relative to VEH and the other BUS doses (p<0.05), but did not significantly impact motor function. Moreover, the same dose conferred selective histological protection as evidenced by smaller cortical lesions, but not greater CA1/CA3 cell survival. No significant behavioral or histological differences were observed among the other BUS doses versus VEH. These data indicate that BUS has a narrow therapeutic dose response, and that 0.3 mg/kg is optimal for enhancing spatial learning and memory in this model of TBI. BUS may have potential as a novel pharmacotherapy for clinical TBI.

Biologic and plastic effects of experimental traumatic brain injury treatment paradigms and their relevance to clinical rehabilitation

Neuroplastic changes, whether induced by traumatic brain injury (TBI) or therapeutic interventions, alter neurobehavioral outcome. Here we present several treatment strategies that have been evaluated by using experimental TBI models and discuss potential mechanisms of action (ie, plasticity) and how such changes affect function.

Increased expression of calcium/calmodulin-dependent protein kinase type II subunit δ after rat traumatic brain injury

Many cellular responses to Ca(2+) signals are mediated by Ca(2+)/calmodulin-dependent enzymes, among which is the Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). CaMKII was originally described in rat brain tissue. In rat brain, four different subunits of the kinase have been identified: α, β, γ, and δ. This study aims to investigate changes of CaMKIIδ after traumatic brain injury and its possible role. Rat traumatic brain injury (TBI) model was established by controlled cortical injury system. In the present study, we mainly investigated the expression and cellular localization of CaMKIIδ after traumatic brain injury. Western blot analysis revealed that CaMKIIδ was present in normal rat brain cortex. It gradually increased, reached a peak at the third day after TBI, and then decreased. Importantly, more CaMKIIδ was colocalized with neuron. In addition, Western blot detection showed that the third day postinjury was also the apoptosis peak indicated by the elevated expression of caspase-3.Importantly, immunohistochemistry analysis revealed that injury-induced expression of CaMKIIδ was colabeled by caspase-3 (apoptosis cells marker). Moreover, pretreatment with the CaMKII inhibitor (KN62) reduced the injury-induced activation of caspase-3. Noticeably, the CaMKII inhibitor KN-62 could reduce TBI-induced cell injury assessed with lesion volume and attenuate behavioral outcome evaluated by motor test. These data suggested that CaMKIIδ may be implicated in the apoptosis of neuron and the recovery of neurological outcomes. However, the inherent mechanisms remained unknown. Further studies are needed to confirm the exact role of CaMKIIδ after brain injury.

Neuroleptic malignant syndrome and closed head injury: A case report and review

Neuroleptic malignant syndrome (NMS) is a rare, but potentially lethal neurological emergency. Fifty percent of traumatic brain injury (TBI) patients will have emotional disorders and post-traumatic agitations. Haloperidol is a neuroleptic antipsychotic medication commonly used in the traumatic brain injury patients due to its advantage of no effect on respiration and conscious level. But it is one of the common medications causing NMS. A 19-year-old male driver involved in the road traffic accident had an acute subdural hematoma, which was immediately evacuated. Postoperatively, he was awake. He was weaned from ventilator and extubated. He received 20 mg of intravenous haloperidol in divided doses with in 24 hours to control his agitation. Next day, he became drowsy, spastic, febrile, and tachycardic with labile blood pressure. He was diagnosed to have NMS, needed intubation, aggressive hydration and pharmacological treatment with dentrolene sodium and bromocriptin. He was weaned from ventilator and extubated on day 17. He was transferred to the ward and then discharged to be followed in out-patient clinic. NMS in head injury patient is rare and difficult to diagnose. Diagnosis of NMS should be suspected if two of the four cardinal signs and symptoms are developed following the use of neuroleptic or dopamine agonist medication withdrawal.

The whisker nuisance task identifies a late-onset, persistent sensory sensitivity in diffuse brain-injured rats

Post-traumatic morbidity reduces the quality of life for traumatic brain injury (TBI) survivors by altering neuropsychological function. After midline fluid percussion injury (FPI), diffuse pathology in the ventral posterior thalamus suggests that somatosensory whisker function may be impaired post-injury. The goals of the present study were to design and validate a task to detect injury-induced somatosensory morbidity (Experiment 1), and to evaluate preliminary applications of the task (Experiment 2). In Experiment 1, male Sprague-Dawley rats were subjected to moderate FPI (approximately 1.9 atm) or sham injury. Over an 8-week time course, the whiskers on both mystacial pads were stimulated manually with an applicator stick in an open field for three 5-min periods. Behavioral responses in this whisker nuisance task were recorded using objective criteria (max score = 16). Sham animals were ambivalent or soothed by whisker stimulation (4.0 +/- 0.8), whereas brain-injured rats showed aggravated responses at 1 week (6.7 +/- 0.9), which became significant at 4 weeks (9.5 +/- 0.5) and 8 weeks (8.4 +/- 1.1) compared to sham injury, indicating chronic injury-induced sensory sensitivity. Total free serum corticosterone levels indicated a significant stress response in brain-injured (125.0 +/- 17.7 ng/mL), but not uninjured animals (74.2 +/- 12.2 ng/mL) in response to whisker stimulation. In Experiment 2, to evaluate applications of the whisker nuisance task, four additional uninjured and brain-injured groups were subjected to mild brain injury only, shaved whiskers after moderate brain injury, repeated whisker nuisance task stimulation after moderate brain injury, or regular opportunities for tactile exploration of an enriched environment after moderate brain injury over 4 weeks post-injury. The whisker nuisance task has the sensitivity to detect mild brain injury (7.7 +/- 1.0), but morbidity was not mitigated by any of the neurorehabilitative interventions. Following diffuse brain injury, the whisker nuisance task is a promising tool to detect post-traumatic morbidity and the efficacy of therapeutic interventions that may restore discrete circuit function in brain-injured patients.

Cerebral blood volume alterations in the perilesional areas in the rat brain after traumatic brain injury--comparison with behavioral outcome

In the traumatic brain injury (TBI) the initial impact causes both primary injury, and launches secondary injury cascades. One consequence, and a factor that may contribute to these secondary changes and functional outcome, is altered hemodynamics. The relative cerebral blood volume (CBV) changes in rat brain after severe controlled cortical impact injury were characterized to assess their interrelations with motor function impairment. Magnetic resonance imaging (MRI) was performed 1, 2, 4 h, and 1, 2, 3, 4, 7, and 14 days after TBI to quantify CBV and water diffusion. Neuroscore test was conducted before, and 2, 7, and 14 days after the TBI. We found distinct temporal profile of CBV in the perilesional area, hippocampus, and in the primary lesion. In all regions, the first response was drop of CBV. Perifocal CBV was reduced for over 4 days thereafter gradually recovering. After the initial drop, the hippocampal CBV was increased for 2 weeks. Neuroscore demonstrated severely impaired motor functions 2 days after injury (33% decrease), which then slowly recovered in 2 weeks. This recovery parallelled the recovery of perifocal CBV. CBV MRI can detect cerebrovascular pathophysiology after TBI in the vulnerable perilesional area, which seems to potentially associate with time course of sensory-motor deficit.

Persistent cognitive dysfunction after traumatic brain injury: A dopamine hypothesis

Traumatic brain injury (TBI) represents a significant cause of death and disability in industrialized countries. Of particular importance to patients the chronic effect that TBI has on cognitive function. Therapeutic strategies have been difficult to evaluate because of the complexity of injuries and variety of patient presentations within a TBI population. However, pharmacotherapies targeting dopamine (DA) have consistently shown benefits in attention, behavioral outcome, executive function, and memory. Still it remains unclear what aspect of TBI pathology is targeted by DA therapies and what time-course of treatment is most beneficial for patient outcomes. Fortunately, ongoing research in animal models has begun to elucidate the pathophysiology of DA alterations after TBI. The purpose of this review is to discuss clinical and experimental research examining DAergic therapies after TBI, which will in turn elucidate the importance of DA for cognitive function/dysfunction after TBI as well as highlight the areas that require further study.

Neuroleptic malignant syndrome in traumatic brain injury patients treated with haloperidol

BACKGROUND

Haloperidol, which is commonly used to treat agitation in critically ill patients, has been associated with the development of neuroleptic malignant syndrome (NMS). The purpose of this manuscript was to review the literature describing NMS and haloperidol use in patients sustaining a traumatic brain injury (TBI) since these patients may be at greater risk for NMS.

METHODS

A computerized search of MEDLINE was conducted (1966-May 2008) to identify all publications in which haloperidol was related to NMS in patients with a TBI. The references of these manuscripts were reviewed for additional literature.

RESULTS

Nine case reports describe the development of NMS in patients with TBI treated with haloperidol for agitation. Cumulative haloperidol doses before the onset of NMS ranged from 10 mg to at least 210 mg. Most of these patients received high dose (> or =30 mg) haloperidol. Four patients received haloperidol parenterally. On diagnosis, of NMS, haloperidol was discontinued in five cases, and all were given supportive care and pharmacologic treatment. Patients were discharged with improved, but diminished functional capacity.

CONCLUSION

Development of NMS in TBI patients treated with haloperidol should be a concern for clinicians since these patients may be at greater risk for this adverse event; especially if the patient is receiving haloperidol at high doses parenterally. Future studies are needed to evaluate the incidence and increased risk of adverse events in patients sustaining a TBI and receiving haloperidol especially since haloperidol is being used more frequently in the critically ill patients.

Pharmacotherapy to enhance arousal: what is known and what is not

Severe brain injury results in a disturbance among a wide range of critical neurotransmitter systems. Each neurotransmitter system places its own functional role while being interconnected to a multitude of other systems and functions. This chapter seeks to review the major neurotransmitter systems involved after severe acquired brain injury. While limited in their construct, animal models of brain injury have demonstrated agents that may assist in the recovery process and those that may further slow recovery. We review further the issue of laboratory evidence and what is transferable to the clinic. Lastly, this chapter reviews published clinical pharmacotherapy studies or trials in the arena of arousal for those with clinical severe brain injury. We discuss limitations as well as findings and present the available evidence in a table-based format. While no clear evidence exists to suggest a defined and rigid pharmacotherapeutic approach, interesting data does suggest that several medications have been associated with enhanced arousal. Several studies are underway or about to begin that will shed more light on the utility of such agents in improving function after severe brain injury. For now, clinicians must employ their own judgment and what has been learned from the limited literature to the care of a challenging group of persons.

Chronic administration of antipsychotics impede behavioral recovery after experimental traumatic brain injury

Antipsychotics are often administered to traumatic brain injured (TBI) patients as a means of controlling agitation, albeit the rehabilitative consequences of this intervention are not well known. Hence, the goal of this study was to evaluate the effects of risperidone (RISP) and haloperidol (HAL) on behavioral outcome after experimental TBI. Anesthetized rats received either a cortical impact or sham injury and then were randomly assigned to five TBI (RISP 0.045mg/kg, RISP 0.45mg/kg, RISP 4.5mg/kg, HAL 0.5mg/kg and VEHicle 1mL/kg) and three Sham (RISP 4.5mg/kg, HAL 0.5mg/kg and VEH 1mL/kg) groups. Treatments began 24h after surgery and were provided once daily for 19 days. Behavior was assessed with established motor (beam-balance/walk) and cognitive (spatial learning/memory in a water maze) tasks on post-operative days 1-5 and 14-19, respectively. RISP and HAL delayed motor recovery, impaired the acquisition of spatial learning, and slowed swim speed relative to VEH in both TBI and sham groups. These data indicate that chronic administration of RISP and HAL impede behavioral recovery after TBI and impair performance in uninjured controls.

Administration of haloperidol and risperidone after neurobehavioral testing hinders the recovery of traumatic brain injury-induced deficits

AIMS

Agitation and aggression are common behavioral sequelae of traumatic brain injury (TBI). The management of these symptoms is critical for effective patient care and therefore antipsychotics are routinely administered even though the benefits vs. risks of this approach on functional outcome after TBI are unclear. A recent study from our group revealed that both haloperidol and risperidone impaired recovery when administered prior to testing. However, the results may have been confounded by drug-induced sedation. Hence, the current study reevaluated the behavioral effects of haloperidol and risperidone when provided after daily testing, thus circumventing the potential sedative effect.

MAIN METHODS

Fifty-four isoflurane-anesthetized male rats received a cortical impact or sham injury and then were randomly assigned to three TBI and three sham groups that received haloperidol (0.5 mg/kg), risperidone (0.45 mg/kg), or vehicle (1.0 mL/kg). Treatments began 24 h after surgery and were administered (i.p.) every day thereafter for 19 days. Motor and cognitive function was assessed on post-operative days 1-5 and 14-19, respectively. Hippocampal CA(1)/CA(3) neurons and cortical lesion volume were quantified at 3 weeks.

KEY FINDINGS

Only risperidone delayed motor recovery, but both antipsychotics impaired spatial learning relative to vehicle (p<0.05). Neither swim speed nor histological outcomes were affected. No differences were observed between the haloperidol and risperidone groups in any task.

SIGNIFICANCE

These data support our previous finding that chronic haloperidol and risperidone hinder the recovery of TBI-induced deficits, and augment those data by demonstrating that the effects are not mediated by drug-induced sedation.

A delayed and chronic treatment regimen with the 5-HT1A receptor agonist 8-OH-DPAT after cortical impact injury facilitates motor recovery and acquisition of spatial learning

An early (i.e., 15min) single systemic administration of the 5-HT(1A) receptor agonist 8-OH-DPAT enhances behavioral recovery after experimental traumatic brain injury (TBI). However, acute administration of pharmacotherapies after TBI may be clinically challenging and thus the present study sought to investigate the potential efficacy of a delayed and chronic 8-OH-DPAT treatment regimen. Forty-eight isoflurane-anesthetized adult male rats received either a controlled cortical impact or sham injury and beginning 24h later were administered 8-OH-DPAT (0.1 or 0.5mg/kg) or saline vehicle (1.0mL/kg) intraperitoneally once daily until all behavioral assessments were completed. Neurobehavior was assessed by motor and cognitive tests on post-operative days 1-5 and 14-19, respectively. The lower dose of 8-OH-DPAT (0.1mg/kg) enhanced motor performance, acquisition of spatial learning, and memory retention vs. both the higher dose (0.5mg/kg) and vehicle treatment (p<0.05). These data replicate previous findings from our laboratory showing that 8-OH-DPAT improves neurobehavior after TBI, and extend those results by demonstrating that the benefits can be achieved even when treatment is withheld for 24h. A delayed and chronic treatment regimen may be more clinically feasible.

Quetiapine for mania due to traumatic brain injury

Secondary mania develops in as many as 9% of persons with traumatic brain injuries. The treatment of posttraumatic mania is not well defined, and agents traditionally used for the treatment of idiopathic manic episodes may not be well suited for use among individuals with traumatic brain injuries. Atypical antipsychotics are indicated for the treatment of idiopathic bipolar disorder, and have been used for other purposes among individuals with posttraumatic neuropsychiatric disturbances. This article offers the first description of the treatment of posttraumatic mania using the atypical antipsychotic quetiapine. Beneficial effects of this agent on posttraumatic mania, cognitive impairments, and functional disability in the subacute post-injury period are described. Possible mechanisms of action are discussed and the need for additional investigation of quetiapine for posttraumatic mania is highlighted.