Effects of the dopaminergic agent and NMDA receptor antagonist amantadine on cognitive function, cerebral glucose metabolism and D2 receptor availability in chronic traumatic brain injury: A study using positron emission tomography (PET)

Assessing the benefits and risks of amantadine for irritability and aggression after traumatic brain injury

OBJECTIVE

To quantify the benefits versus harms of amantadine in the treatment of irritability and aggression following traumatic brain injury.

METHODS

Secondary outcome data from a randomized controlled multisite trial of amantadine 100 mg twice daily were used to calculate number-needed-to-treat (NNT). Given prior findings of positive clinician-perceived effects and low incidence of adverse events, we hypothesized low number-needed-to-treat for benefit (NNTB; high benefit) and high number-needed-to-treat for harm (NNTH; low risk) based on the clinician ratings, supporting the use of amantadine in clinical practice. Specifically, NNTB values were calculated using number of individuals with improvement on the Clinician Global Impressions-Global Improvement scale (GI). NNTB values were computed using number of individuals with worsening on the GI and experiencing serious and any adverse events.

RESULTS

Based on clinician ratings, on average for every six patients treated with amantadine rather than placebo, one extra patient would be expected to improve (NNTB = 6.4; 95% confidence interval [CI]: [3.3-76.8]). More participants in the placebo group worsened than in the amantadine group, but the result was not statistically significant (NNTH = -92.4; 95% CI: [NNTB -32.9 to infinity to NNTH -19.2]). The amantadine and placebo groups did not differ on the numbers of adverse events experienced during the trial.

CONCLUSION

Clinician ratings suggest modest benefit of amantadine 100 mg twice daily with low risk to appropriately selected patients with adequate renal clearance. Thus, amantadine should be considered a treatment option for the experienced brain injury clinician. These data may support treatment decisions when a pharmaceutical agent is being considered to control irritability/aggression.

Review of spinal cord stimulation for disorders of consciousness

PURPOSE OF REVIEW

High-cervical spinal cord stimulation can alter cortical activity and cerebral metabolism. These effects are potentially beneficial for disorders of consciousness. A better understanding of the effects of clinical application of stimulation is needed. We aimed to evaluate the existing literature to determine the state of available knowledge. We performed a literature review of clinical studies assessing cervical spinal cord epidural stimulation for disorders of consciousness. Only peer-reviewed articles reporting preoperative and postoperative clinical status were included.

RECENT FINDINGS

Nineteen studies were included. A total of 532 cases were reported, and 255 patients were considered responsive (47.9%). Considering only studies published after the definition of minimally conscious state (MCS) as an entity, 402 individuals in unresponsive wakefulness syndrome (UWS) and 113 in MCS were reported. Responsiveness to SCS was reported in 170 UWS patients (42.3%) and in 78 MCS cases (69.0%), although the criteria for responsiveness and outcome measures varied among publications.

SUMMARY

Cervical SCS yielded encouraging results in patients with disorders of consciousness and seems to be more effective in MCS. More extensive investigation is needed to understand its potential role in clinical practice.

Effects of Amantadine Sulfate on Motor Impairment and Execution of Motor Sequences in Patients With Parkinson Disease

BACKGROUND

Intravenous application of amantadine sulfate induces a rapid improvement of motor behavior in patients with Parkinson disease.

OBJECTIVES

To determine efficacy of daily infusion of 200 mg amantadine sulfate on scored motor symptoms and performance of standardized movement sequences with components of low and high cognitive efforts.

METHODS

Thirty-one participants received infusions of amantadine sulfate in addition to their previous stable drug regimens on 3 consecutive days. Motor symptoms of upper limbs were determined with selected items of the part motor examination of the Unified Parkinson's Disease Rating Scale. Instrumental tasks were executed under cued conditions before and after the infusions.

RESULTS

Scored motor symptoms and components with a need for a higher cognitive load became better. Performance of motion series, characterized by an automated set with low cognitive efforts, did not improve.

CONCLUSION

Our trial outcomes suggest that the amantadine has a positive impact on cognitive abilities, drive, and vigilance, all of which are necessary for carrying out of higher brain functions.

The kynurenine pathway in traumatic brain injuries and concussion

Up to 10 million people per annum experience traumatic brain injury (TBI), 80-90% of which are categorized as mild. A hit to the brain can cause TBI, which can lead to secondary brain injuries within minutes to weeks after the initial injury through unknown mechanisms. However, it is assumed that neurochemical changes due to inflammation, excitotoxicity, reactive oxygen species, etc., that are triggered by TBI are associated with the emergence of secondary brain injuries. The kynurenine pathway (KP) is an important pathway that gets significantly overactivated during inflammation. Some KP metabolites such as QUIN have neurotoxic effects suggesting a possible mechanism through which TBI can cause secondary brain injury. That said, this review scrutinizes the potential association between KP and TBI. A more detailed understanding of the changes in KP metabolites during TBI is essential to prevent the onset or at least attenuate the severity of secondary brain injuries. Moreover, this information is crucial for the development of biomarker/s to probe the severity of TBI and predict the risk of secondary brain injuries. Overall, this review tries to fill the knowledge gap about the role of the KP in TBI and highlights the areas that need to be studied.

Adamantanes for the treatment of neurodegenerative diseases in the presence of SARS-CoV-2

Advent of the acute respiratory coronavirus SARS-CoV-2 has resulted in the search for novel antiviral agents and in the repurposing of existing agents with demonstrated efficacy against other known coronaviruses in the search for an agent with antiviral activity for use during the COVID-19 pandemic. Adamantanes including amantadine, rimantadine, and memantine have well-established benefit in the treatment of neurodegenerative diseases including Parkinson's disease (PD), Alzheimer's disease (AD) and fatigue related to Multiple sclerosis (MS) all of which are known comorbidities related to COVID-19 Moreover, results of basic pharmacological studies both in vitro and in vivo reveal that amantadine has the potential to inhibit SARS-CoV-2 via down-regulation of host-cell proteases resulting in impaired viral genome release into the host cell and via amantadine's property as an NMDA receptor antagonist resulting in the prevention of the acute lung injury and respiratory distress that is characteristic of COVID-19. Cases suggestive of COVID-19 prophylaxis have been reported in patients with PD or MS or severe cognitive impairment treated in all cases for several months with an adamantane [amantadine or memantine] who were subsequently infected with SARS-CoV-2 confirmed by RT-PCR, and, in all cases, no signs of infectious disease were encountered. Amantadine is effective for the treatment of fatigue in MS and for the neurological complications of Traumatic Brain Injury (TBI).

Opioid-induced short-term consciousness improvement in patients with disorders of consciousness

Introduction

Effective treatment to facilitate recovery from prolonged disorders of consciousness is a complex topic for the medical community. In clinical practice, we have found that a subset of patients has a short-term improvement of consciousness after general anesthesia.

Methods

To determine the clinical factors responsible for the consciousness improvement, we enrolled 50 patients with disorders of consciousness who underwent surgery from October 2021 to June 2022. Their states of consciousness were evaluated before surgery, within 48 h after surgery, and 3 months after surgery. Clinical-related factors and intraoperative anesthetic drug doses were collected and compared between patients with and without consciousness improvement. Independent associations between selected factors and postoperative improvement were assessed using multivariate logistical regression analyses.

Results

Postoperative short-term consciousness improvement was found in 44% (22/50) of patients, with significantly increased scores of auditory and visual subscales. Patients with traumatic etiology, a preoperative diagnosis of minimally conscious state, and higher scores in the auditory, visual, and motor subscales were more likely to have postoperative improvement. This short-term increase in consciousness after surgery correlated with patients' abilities to communicate in the long term. Furthermore, the amount of opioid analgesic used was significantly different between the improved and non-improved groups. Finally, analgesic dose, etiology, and preoperative diagnosis were independently associated with postoperative consciousness improvement.

Discussion

In conclusion, postoperative consciousness improvement is related to the residual consciousness of the patient and can be used to evaluate prognosis. Administration of opioids may be responsible for this short-term improvement in consciousness, providing a potential therapeutic approach for disorders of consciousness.

Aminoadamantanes: from treatment of Parkinson's and Alzheimer's disease to symptom amelioration of long COVID-19 syndrome?

INTRODUCTION

The aminoadamantanes amantadine and memantine are well known. They mainly act as N-methyl-D-aspartate antagonists.

AREAS COVERED

The antiviral drug amantadine moderately ameliorates impaired motor behavior in patients with Parkinson's disease. Memantine provides beneficial effects on memory function in patients with advanced Alzheimer's disease already treated with acetylcholine esterase inhibitors. Both compounds counteract impaired monoamine neurotransmission with associated symptoms, such as depression. They improve vigilance, lack of attention and concentration, fatigue syndromes according to clinical findings in patients with chronic neurodegenerative processes. Their extrasynaptic N-methyl-D-Aspartate receptor blockade weakens a prolonged influx of Ca²⁺ ions as the main responsible components of neuronal excitotoxicity. This causes neuronal dying and associated functional deficits.

EXPERT OPINION

We suggest aminoadamantanes as future therapies for amelioration of short- and long-term consequences of a COVID 19 infection. Particularly the extended-release amantadine formulations will be suitable. They showed better clinical efficacy compared with the conventional available compounds. Amantadine may particularly be suitable for amelioration of fatigue or chronic exhaustion, memantine for improvement of cognitive deficits. Clinical research in patients, who are affected by the short- and long-term consequences of a COVID 19 infection, is warranted to confirm these still hypothetical putative beneficial effects of aminoadamantanes.

Enhancing management of agitation after traumatic brain injury: Psychiatric perspectives and quantitative assessments

BACKGROUND

Post-traumatic agitation is a common and problematic complication after traumatic brain injury. It may present with features consistent with psychiatric disorders, which may provide clues as to management.

OBJECTIVE

This is a narrative review of pertinent literature and a description of a collaborative clinical approach utilizing psychiatric and brain injury rehabilitation strategies to optimize outcomes in the management of post-traumatic agitation.

METHODS

Describe and provide evidence for a transdisciplinary clinical approach supported by existing literature and clinical experience.

RESULTS

Given the heterogeneity of the problem and limitations in the current literature there is no standardized approach to manage post-traumatic agitation; nevertheless, a strategy is proposed that clinicians may utilize to guide treatment and assess efficacy of the chosen intervention(s).

CONCLUSION

A clinical approach that uses quantitative assessment of targeted behavior to objectively evaluate pharmacological interventions that are generated by a collaborative approach may yield improved outcomes for managing post-traumatic agitation.

Improved survival in ICU in severe COVID-19 associated with amantadine use - retrospective study

INTRODUCTION

Possible immunomodulatory effect of amantadine in patients treated in intensive care units (ICU), mostly among patients with brain injuries or vascular diseases was observed in several studies. Potential antiviral effect of amantadine against SARS CoV-2 was discarded in clinical trials, however immunomodulatory potential was not studied.

OBJECTIVES

The aim of the study was to investigate the effect of immunomodulatory amantadine therapy on mortality in patients with respiratory insufficiency due to COVID-19 requiring mechanical ventilation in ICU.

PATIENTS AND METHODS

Retrospective analysis of 241 cases of 141 (58.5%) receiving intravenous amantadine sulfate vs. 100 (41.5%) controls on standard of care only was performed.

RESULTS

Overall mortality was 72.6%, being notably lower among amantadine treated patients (59.5%, n=84) compared to controls (91%, n=91), p= 0.001. In multivariate models administration of amantadine was independently associated with lower mortality rate [HR: 0.220 (CI: 0.146 - 0.333), p = 0.001)]. Furthermore, survival was improved in patients who received amantadine late - administration of amantadine after 5th day was independently associated with lower mortality [HR: 0.560 (CI: 0.313 - 0.999), p = 0.050).

CONCLUSIONS

In patients treated in ICU with severe respiratory failure administration of amantadine associated with lower mortality, which may be associated with potential anti-inflammatory and immunomodulatory effects of this agent.

N-methyl-D-aspartate receptor antagonists in improving cognitive deficits following traumatic brain injury: a systematic review

OBJECTIVE

To review the role of N-methyl-D-aspartate receptor (NMDAR) antagonists in managing post-TBI cognitive deficits.

METHODS

A search of PubMed, Embase, and Cochrane was conducted on Jan 12, 2021 without publication date or language restriction.

RESULTS

Forty-seven studies were included, involving 20 (42.6%) randomized controlled trials. Four (8.5%) studies had a low risk of bias (RoB), while 34 (72.3%) had unclear and nine (19.2%) had high RoB. Six NMDAR antagonists had been investigated: amantadine (n = 32), memantine (n = 4), magnesium (n = 4), traxoprodil (n = 3), selfotel (n = 2), and dextromethorphan (n = 2).

CONCLUSION

Although some benefits were observed, there are still some concerns regarding the efficacy and safety of NMDAR antagonists in improving post-TBI cognitive deficits. Further research is required to examine whether (i) these agents, notably amantadine, could accelerate cognitive improvement and shorten the hospital stay, (ii) these agents affect different cognitive domains/subdomains in the same direction, (iii) an optimal therapeutic time window exists, (iv) a member of this drug class can be proved to be effective without interfering in non-excitotoxic actions of glutamate, (v) they can be more effective as part of combination therapies or in particular subgroups of patients with TBI.

Current Clinical Trials in Traumatic Brain Injury

Traumatic brain injury (TBI) is one of the leading causes of morbidity, disability and mortality across all age groups globally. Currently, only palliative treatments exist, but these are suboptimal and do little to combat the progressive damage to the brain that occurs after a TBI. However, multiple experimental treatments are currently available that target the primary and secondary biochemical and cellular changes that occur after a TBI. Some of these drugs have progressed to clinical trials and are currently being evaluated for their therapeutic benefits in TBI patients. The aim of this study was to identify which drugs are currently being evaluated in clinical trials for TBI. A search of ClinicalTrials.gov was performed on 3 December 2021 and all clinical trials that mentioned “TBI” OR “traumatic brain injury” AND “drug” were searched, revealing 362 registered trials. Of the trials, 46 were excluded due to the drug not being mentioned, leaving 138 that were completed and 116 that were withdrawn. Although the studies included 267,298 TBI patients, the average number of patients per study was 865 with a range of 5–200,000. Of the completed studies, 125 different drugs were tested in TBI patients but only 7 drugs were used in more than three studies, including amantadine, botulinum toxin A and tranexamic acid (TXA). However, previous clinical studies using these seven drugs showed variable results. The current study concludes that clinical trials in TBI have to be carefully conducted so as to reduce variability across studies, since the severity of TBI and timing of therapeutic interventions were key aspects of trial success.

Amantadine as a Potential Treatment for Marchiafava–Bignami Disease: Case Reports and a Possible Mechanism

Introduction

Several reports have described the use of amantadine for managing symptoms in Marchiafava–Bignami disease (MBD); however, amantadine's role for the treatment of MBD symptoms is unclear. Here, we describe 2 patients with MBD who were treated with amantadine and hypothesize a potential mechanism responsible for clinical benefit. Case 1. A 38-year-old woman with excessive wine drinking presented with agitation, impaired speech, and a minimally conscious state. MRI revealed lesions in the splenium and genu. After being diagnosed with MBD, she was treated with intravenous thiamine, multivitamins, and 100 mg of amantadine twice a day for 2 weeks. She recovered to near baseline after 3 weeks. Case 2. A 54-year-old woman with years of heavy alcohol use presented with sudden bradyphrenia, acalculia, disinhibited behavior, weakness, and urinary incontinence. MRI revealed a large anterior callosal lesion. Two years after initial recovery from MBD, she noted that consuming “energy drinks” resulted in a transient, near-complete resolution of her residual behavioral, fatigue, and language symptoms. 100 mg of amantadine twice a day was trialled. After noted improvement, a further escalation to 200 mgs 3 times a day resulted in significant improvement in language and behavioral symptoms.

Conclusion

Amantadine in addition to vitamins may be beneficial in the treatment of MBD. It is possible that the dopaminergic effect of amantadine leads to improved recovery and function in dopamine-mediated pathways, including mesocortical and mesolimbic pathways during initial recovery, as well as improved speech, behavior, and fatigue in the following months. The role of amantadine in the treatment of MBD warrants further study.

Early amantadine treatment reduces the risk of death in patients with large hemisphere infarctions:a Chinese hospital-based study

Background

Amantadine hydrochloride is one of the most frequently prescribed drugs for patients with severe traumatic brain injury in restoring consciousness and accelerating the pace of functional recovery. However, there is a paucity of studies on the effectiveness of amantadine in patients with severe stroke especially large hemisphere infarction (LHI). The present study aimed to investigate whether amantadine treatment is associated with better clinical outcomes in conservatively treated LHI patients.

Methods

We retrospectively collected conservatively treated LHI patients according to inclusion/exclusion criteria. The patients were divided into two groups based on the treatment regimen, whether they did receive amantadine hydrochloride in addition to standard therapy (ST) or not. The primary outcomes were in-hospital death, 3-month mortality, and unfavorable outcome (defined as modified Rankin Scale score of 4 to 6). All outcomes were compared between the two groups before and after propensity score matching (PSM). Multivariate logistic regression was performed to identify the association between early amantadine hydrochloride treatment and clinical outcomes in LHI patients.

Results

Thirty-one LHI patients treated with amantadine combined with ST and 127 patients treated with ST were enrolled. Amantadine group had a shorter prehospital delay (median: 2 vs. 10 h), a higher baseline NIHSS score (21.71 ± 4.76 vs. 17.49 ± 5.84), and a higher rate of dominant hemisphere involvement (67.74% vs. 45.67%). After PSM, amantadine treatment significantly reduced the risk of in-hospital death (7.41% vs. 31.11%, p=0.019) and 3-month mortality (25.93% vs. 55.56%, p=0.008). Amantadine treatment yielded a significant decrease in death in-hospital (before PSM: OR 0.143, 95% CI 0.034 to 0.605; after PSM: OR 0.113, 95% CI 0.020 to 0.635) and 3-month mortality (before PSM: OR 0.214, 95% CI 0.077 to 0.598; after PSM: OR 0.176, 95% CI 0.053 to 0.586) in unmatched and matched multivariate analyses.

Conclusion

The results of our study provide initial evidence that early amantadine treatment was associated with a decrease in death in conservatively treated LHI patients. Considering the limitations of observational study, randomized controlled trials with a large sample size may help provide a clearer picture of the utility of amantadine in LHI patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02444-w.

Quantitative multimodal imaging in traumatic brain injuries producing impaired cognition

PURPOSE OF REVIEW

Cognitive impairments are a devastating long-term consequence following traumatic brain injury (TBI). This review provides an update on the quantitative mutimodal neuroimaging studies that attempt to elucidate the mechanism(s) underlying cognitive impairments and their recovery following TBI.

RECENT FINDINGS

Recent studies have linked individual specific behavioural impairments and their changes over time to physiological activity and structural changes using EEG, PET and MRI. Multimodal studies that combine measures of physiological activity with knowledge of neuroanatomical and connectivity damage have also illuminated the multifactorial function-structure relationships that underlie impairment and recovery following TBI.

SUMMARY

The combined use of multiple neuroimaging modalities, with focus on individual longitudinal studies, has the potential to accurately classify impairments, enhance sensitivity of prognoses, inform targets for interventions and precisely track spontaneous and intervention-driven recovery.

Amantadine: reappraisal of the timeless diamond-target updates and novel therapeutic potentials

The aim of the current review was to provide a new, in-depth insight into possible pharmacological targets of amantadine to pave the way to extending its therapeutic use to further indications beyond Parkinson's disease symptoms and viral infections. Considering amantadine's affinities in vitro and the expected concentration at targets at therapeutic doses in humans, the following primary targets seem to be most plausible: aromatic amino acids decarboxylase, glial-cell derived neurotrophic factor, sigma-1 receptors, phosphodiesterases, and nicotinic receptors. Further three targets could play a role to a lesser extent: NMDA receptors, 5-HT3 receptors, and potassium channels. Based on published clinical studies, traumatic brain injury, fatigue [e.g., in multiple sclerosis (MS)], and chorea in Huntington's disease should be regarded potential, encouraging indications. Preclinical investigations suggest amantadine's therapeutic potential in several further indications such as: depression, recovery after spinal cord injury, neuroprotection in MS, and cutaneous pain. Query in the database http://www.clinicaltrials.gov reveals research interest in several further indications: cancer, autism, cocaine abuse, MS, diabetes, attention deficit-hyperactivity disorder, obesity, and schizophrenia.

A Review of Pharmacologic Neurostimulant Use During Rehabilitation and Recovery After Brain Injury

OBJECTIVE

To describe the efficacy and safety of pharmacologic neurostimulants after neurological injuries such as ischemic or hemorrhagic stroke and traumatic brain injury (TBI), critically evaluate the available literature, and make recommendations regarding which neurostimulants should be considered for use in clinical practice.

DATA SOURCES

A literature search of PubMed was performed (1953 to October 2020) to identify relevant articles. Search terms included the following: "neurostimulant, neurorehabilitation" AND "traumatic brain injury, cerebrovascular accident, or stroke." This review is limited to prospective studies and observational trials.

STUDY SELECTION AND DATA EXTRACTION

Relevant English-language studies conducted in humans were considered.

DATA SYNTHESIS

Cognitive and motor deficits caused by stroke and TBI account for high rates of long-term disability. Although not well-established, pharmacologic agents, broadly characterized as neurostimulants, may be prescribed after brain injury to treat these deficits. When prescribing these medications, it is imperative to be aware of the supporting evidence in order to accurately gauge the risk-benefit profile of each agent.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

The following presents a literature review critically evaluating clinical studies that investigate neurostimulant use after brain injury. The intent of this review is to serve as an evidence-based guide for clinicians.

CONCLUSIONS

The pharmacologic agent with the most supporting literature is amantadine used for cognitive improvement after TBI. Other neurostimulants with positive, despite more limited, evidence include methylphenidate, modafinil, levodopa, and citalopram. Caution is warranted with other neurostimulants given higher rates of adverse effects or lack of benefit observed in clinical trials.

Efficacy and safety of amantadine as a treatment for apathy after brain injury: Two single-case experimental design studies

Studies on the efficacy of amantadine as a treatment for apathy after brain injury are scarce and of low quality. We examined the efficacy and safety of amantadine for treatment of apathy in two individuals with brain injury.Two double-blind, randomized, single-case experimental (baseline-amantadine-placebo-withdrawal) design (SCED) studies. Apathy measures included a Visual Analogue Scale (VAS), the Neuropsychiatric Inventory (NPI) apathy subscale and the Behavior Rating Inventory of Executive Function for Adults "Initiate" subscale. Safety measures included a rating scale of possible side effects of amantadine and physical examinations.No difference in apathy symptoms (VAS) between baseline and amantadine phase was found in case 1 (NAP = 0.55). Surprisingly, in case 2, apathy symptoms deteriorated from baseline to amantadine phase (NAP = 0.28, 90% CI = -0.69 to -0.20) and improved from amantadine to placebo phase (NAP = 0.92, 90% CI = 0.60-1.00). This improvement was also found on the NPI apathy subscale. Side effects of amantadine were observed in case 2.In this SCED study, amantadine did not improve apathy symptoms in two individuals with brain injury. However, this study shows that side effects of amantadine can occur which lead to a significant decrease in well-being. More high quality studies are required.

Persistent vegetative state after severe cerebral hemorrhage treated with amantadine: A retrospective controlled study

Amantadine is currently recommended for use in patients of posttraumatic brain injury with unconsciousness. However, the application of amantadine in consciousness disturbance after cerebral hemorrhage has only been rarely reported. This allows for a further exploration of the role of amantadine in the treatment of PVS resulting from severe cerebral hemorrhage.Retrospective cohort study from 1/2015 to 7/2019 in Beijing Chaoyang hospital. We included adult patients treated with amantadine after severe cerebral hemorrhage in PVS. Primary outcome was time of consciousness recovery and Glasgow Out Scale scores after 5 months from onset. We compared characteristics and outcomes to a control cohort. matched on age, Coma Recovery Scale-Revised score, volume and location of hemorrhage.Among the 12 patients who received amantadine treatment, 6 patients regained consciousness (50%) after 5 months of disease onset, but were still severely disabled. Besides, the time for regaining consciousness was within 3 months of disease onset. The remaining 6 patients were still in a PVS. Compared with the amantadine group, the consciousness recovery rate (50% vs 33.3%, P = .68) after 5 months in the nested control group was not significantly different. The awakening time for patients in the amantadine group was earlier than the control group (100% vs 25%, P = .03).In this study, amantadine can accelerate the recovery of consciousness in patients following severe cerebral hemorrhage. We recommend further randomized controlled studies to determine the efficacy of amantadine.

Amantadine and memantine: a comprehensive review for acquired brain injury

This comprehensive review discusses clinical studies of patients following brain injuries (traumatic, acquired, or stroke), who have been treated with amantadine or memantine. Both amantadine and memantine are commonly used in the acute rehabilitation setting following brain injuries, despite their lack of FDA-approval for neuro-recovery. Given the broad utilization of such agents, there is a need to review the evidence supporting this common off-label prescribing. The purpose of this review is to describe the mechanisms of action for memantine and amantadine, as well as to complete a comprehensive review of the clinical uses of these agents. We included 119 original, clinical research articles from NCBI Medline, published before 2019. We focused on the domains of neuroplasticity, functional recovery, motor recovery, arousal, fatigue, insomnia, behavior, agitation, and cognition. Most of the existing research supporting the use of amantadine and memantine in recovery from brain injuries was done in very small populations, limiting the significance of conclusions. While most studies are positive; small effect sizes are usually reported, or populations are subject to bias. Furthermore, evidence is so limited that this review includes research regarding both acute and chronic acquired brain injury populations. Fortunately, reported short-term side effects generally are modest, and stop soon after amantadine/memantine is discontinued. However, responses are inconsistent, and the phenotype of responders remains elusive.

Recent Clinical Advances in Pharmacotherapy for Levodopa-Induced Dyskinesia

Onset of involuntary movement patterns of the face, body and limbs are known as dyskinesia. They mostly appear in association with long-term levodopa (L-dopa) therapy in patients with Parkinson's disease. Consequences include patient distress, caregiver embarrassment and reduced quality of life. A severe intensity of this motor complication may result in troublesome disability; however, patients typically prefer motor behaviour with slight, non-troublesome dyskinesia to 'OFF' states. Pharmacotherapy of dyskinesia is complex. Continuous nigrostriatal postsynaptic dopaminergic receptor stimulation may delay onset of L-dopa-associated dyskinesia, while non-physiological, 'pulsatile' receptor stimulation facilitates appearance of dyskinesia. In the past, there have been many clinical trial failures with compounds that were effective in animal models of dyskinesia. Only the N-methyl-D-aspartate antagonist amantadine has shown moderate antidyskinetic effects in small well-designed clinical studies. Amantadine is an old antiviral compound, which moderately improves impaired motor behaviour. Recently, there has been a resurgence of its use due to the US Food and Drug Administration approval of an extended-release (ER) amantadine formulation for treatment of L-dopa-induced dyskinesia. This pharmacokinetic innovation improved dyskinesia and 'OFF' states in pivotal trials, with a once-daily oral application in the evening. Amantadine ER provides higher and more continuous amantadine plasma bioavailability than conventional immediate-release formulations, which require administration up to three times daily.

Approaches to Monitor Circuit Disruption after Traumatic Brain Injury: Frontiers in Preclinical Research

Mild traumatic brain injury (TBI) often results in pathophysiological damage that can manifest as both acute and chronic neurological deficits. In an attempt to repair and reconnect disrupted circuits to compensate for loss of afferent and efferent connections, maladaptive circuitry is created and contributes to neurological deficits, including post-concussive symptoms. The TBI-induced pathology physically and metabolically changes the structure and function of neurons associated with behaviorally relevant circuit function. Complex neurological processing is governed, in part, by circuitry mediated by primary and modulatory neurotransmitter systems, where signaling is disrupted acutely and chronically after injury, and therefore serves as a primary target for treatment. Monitoring of neurotransmitter signaling in experimental models with technology empowered with improved temporal and spatial resolution is capable of recording in vivo extracellular neurotransmitter signaling in behaviorally relevant circuits. Here, we review preclinical evidence in TBI literature that implicates the role of neurotransmitter changes mediating circuit function that contributes to neurological deficits in the post-acute and chronic phases and methods developed for in vivo neurochemical monitoring. Coupling TBI models demonstrating chronic behavioral deficits with in vivo technologies capable of real-time monitoring of neurotransmitters provides an innovative approach to directly quantify and characterize neurotransmitter signaling as a universal consequence of TBI and the direct influence of pharmacological approaches on both behavior and signaling.

Stimulant Use in the Management of Mild Traumatic Brain Injury: A Qualitative Literature Review

Objective: Mild traumatic brain injury (mTBI) often presents with cognitive complaints including difficulty with attention and concentration. As these symptoms resemble those of ADHD, stimulants may be a potential treatment for mTBI. This review evaluates the literature on the use of stimulants for the treatment of mTBI. Method: A systematic evaluation of the literature using six databases: Ovidmedline, Pubmed, psychINFO, CINAH, Embase, and Cochrane. Broad search terms were used and studies were included that evaluate the use of stimulant and stimulant-like medications in the mTBI population. Data extracted included stimulant type and dosing, symptoms targeted, outcomes, safety and tolerability, and if the study population had ADHD. Results: Nine studies were identified that met the inclusion criteria. Immediate release methylphenidate and amantadine were used for treatment. Methylphenidate had some impact on attention, fatigue, and depression. However, due to the limited number of studies and heterogeneity of study populations, symptoms targeted, and outcome measures used, meaningful conclusions regarding the effect of stimulants in mTBI could not be made. No study evaluated for the presence of ADHD within the study population, despite stimulants being the mainstay treatment for ADHD. Conclusion: PProspective studies on the use of stimulants in mTBI, that evaluate participants for a diagnosis of ADHD, are needed.

The Efficacy and Harms of Pharmacological Interventions for Aggression After Traumatic Brain Injury-Systematic Review

Background: Aggression is a commonly reported problem following traumatic brain injury (TBI). It may present as verbal insults or outbursts, physical assaults, and/or property destruction. Aggressive behavior can fracture relationships and impede participation in treatment as well as a broad range of vocational and social activities, thereby reducing the individual's quality of life. Pharmacological intervention is frequently used to control aggression following TBI. The aim of this systematic review was to critically evaluate the evidence regarding efficacy of pharmacological interventions for aggression following TBI in adults.

Methods: We reviewed studies in English, available before December 2018. MEDLINE, PubMed, CINAHL, EMBASE, PsycINFO, and CENTRAL databases were searched, with additional searching of key journals, clinical trials registries, and international drug regulators. The primary outcomes of interest were reduction in the severity of aggression and occurrence of harms. The secondary outcomes of interest were changes in quality of life, participation, psychological health (e.g., depression, anxiety), and cognitive function. Evidence quality was assessed using the Cochrane Risk of Bias tool and the Joanna Briggs Institute Critical Appraisal Instruments.

Results: Ten studies were identified, including five randomized controlled trials (RCTs) and five case series. There were positive, albeit mixed, findings for the RCTs examining the use of amantadine in reducing irritability (n = 2) and aggression (n = 2). There were some positive findings favoring methylphenidate in reducing anger (n = 1). The evidence for propranolol was weak (n = 1). Individual analysis revealed differential drug response across individuals for both methylphenidate and propranolol. The less rigorous studies administered carbamazepine (n = 2), valproic acid (n = 1), quetiapine (n = 1), and sertraline (n = 1), and all reported reductions in aggression. However, given the lack of a control group, it is difficult to discern treatment effects from natural change over time.

Conclusions: This review concludes that a recommendation for use of amantadine to treat aggression and irritability in adults following TBI is appropriate. However, there is a need for further well-designed, adequately powered and controlled studies of pharmacological interventions for aggression following TBI.

Brain interrupted: Early life traumatic brain injury and addiction vulnerability

Recent reports provide evidence for increased risk of substance use disorders (SUD) among patients with a history of early-life traumatic brain injury (TBI). Preclinical research utilizing animal models of TBI have identified injury-induced inflammation, blood-brain barrier permeability, and changes to synapses and neuronal networks within regions of the brain associated with the perception of reward. Importantly, these reward pathway networks are underdeveloped during childhood and adolescence, and early-life TBI pathology may interrupt ongoing maturation. As such, maladaptive changes induced by juvenile brain injury may underlie increased susceptibility to SUD. In this review, we describe the available clinical and preclinical evidence that identifies SUD as a persistent psychiatric consequence of pediatric neurotrauma by discussing (1) the incidence of early-life TBI, (2) how preclinical studies model TBI and SUD, (3) TBI-induced neuropathology and neuroinflammation in the corticostriatal regions of the brain, and (4) the link between childhood or adolescent TBI and addiction in adulthood. In summary, preclinical research utilizes an innovative combination of models of early-life TBI and SUD to recapitulate clinical features and to determine how TBI promotes a risk for the development of SUD. However, causal processes that link TBI and SUD remain unclear. Additional research to identify and therapeutically target underlying mechanisms of aberrant reward pathway development will provide a launching point for TBI and SUD treatment strategies.

Treatment of Pediatric Concussion

Concussions have gained attention in medical literature, legal literature, and lay media over the past several years as a public health affecting children, particularly those who do not improve in the first few days after an injury. We discuss strategies for acute management immediately after a concussion and an introduction to medical and non-medical options for treatment of the complex symptoms that persist in some patients with concussions. We examine the role of rest and exercise during recovery. We briefly discuss the role of the multidisciplinary approach to concussion in a setting that engages multiple specialists. Finally, we address policy changes related to sport-concussions and their efficacy in improving long term outcomes.

Neurotransmitter changes after traumatic brain injury: an update for new treatment strategies

Traumatic brain injury (TBI) is a pervasive problem in the United States and worldwide, as the number of diagnosed individuals is increasing yearly and there are no efficacious therapeutic interventions. A large number of patients suffer with cognitive disabilities and psychiatric conditions after TBI, especially anxiety and depression. The constellation of post-injury cognitive and behavioral symptoms suggest permanent effects of injury on neurotransmission. Guided in part by preclinical studies, clinical trials have focused on high-yield pathophysiologic mechanisms, including protein aggregation, inflammation, metabolic disruption, cell generation, physiology, and alterations in neurotransmitter signaling. Despite successful treatment of experimental TBI in animal models, clinical studies based on these findings have failed to translate to humans. The current international effort to reshape TBI research is focusing on redefining the taxonomy and characterization of TBI. In addition, as the next round of clinical trials is pending, there is a pressing need to consider what the field has learned over the past two decades of research, and how we can best capitalize on this knowledge to inform the hypotheses for future innovations. Thus, it is critically important to extend our understanding of the pathophysiology of TBI, particularly to mechanisms that are associated with recovery versus development of chronic symptoms. In this review, we focus on the pathology of neurotransmission after TBI, reflecting on what has been learned from both the preclinical and clinical studies, and we discuss new directions and opportunities for future work.

Evaluating ADS5102 (amantadine) for the treatment of Parkinson's disease patients with dyskinesia

Introduction: Amantadine is an old, antiviral compound that moderately ameliorates impaired motor behaviour in Parkinson's disease. Its current resurgence results from the novel retarded release amantadine hydrochloride formulation, ADS5102, which has also received approval for the treatment of levodopa-related involuntary movements known as dyskinesia. Areas covered: This non-systematic, narrative drug evaluation discusses the value of ADS5102 for patients with Parkinson's disease. ADS5102 is orally applied once daily in the evening. This capsule provides higher and more continuous amantadine plasma concentrations than conventional amantadine immediate release formulations with their two to three times daily intake plan. Expert opinion: ADS5102 was superior to placebo in clinical trials. They aimed for the amelioration of motor complications, particularly at 'OFF' periods and with dyskinesia in fluctuating levodopa treated patients with Parkinson's disease. Side effects and tolerability were similar to the well-known effects of conventional amantadine formulations. ADS5102 simplifies treatment and improves compliance problems in the long run. The marketing of ADS5102 outside the US will be complex for return of research costs and investments required for its manufacturing. Indeed, worldwide institutional price regulation scenarios often only consider new therapeutic mode of actions as being innovative as opposed to old drugs with improved pharmacokinetic behaviour.

Effect of amantadine on vegetative state after traumatic brain injury: a functional magnetic resonance imaging study

OBJECTIVE

We assessed the use of functional magnetic resonance imaging (fMRI) to observe residual brain function and responsiveness to amantadine in a patient in a vegetative state (VS) following traumatic brain injury.

METHOD

We observed cerebral cortex activation in a 52-year-old man in a VS, and in a healthy individual using fMRI during passive listening and motor-imagery tasks. The patient received oral amantadine for 3 months. fMRI was repeated after treatment.

RESULTS

Activation around the left insular regions occurred during stimulation by a familiar voice, and activity in the left temporal and bi-occipital cortices occurred during stimulation by a familiar/unfamiliar voice. Activity in the bilateral frontal and parietal cortices occurred during the motor-imagination task. Brain cortex activation was reduced in the VS patient compared with the healthy volunteer. However, the patient responded to certain auditory stimuli and motor imagery, suggesting that he retained some intact auditory and motor cortical functions. fMRI scans after 3 months of treatment showed increased activation of brain areas corresponding to task instructions.

CONCLUSION

fMRI could be used to observe the effects of amantadine on brain function, and to aid the diagnosis and prognostic prediction in VS patients in terms of recovery and rehabilitation planning.

Cocaine self-administration is increased after frontal traumatic brain injury and associated with neuroinflammation

Traumatic brain injury (TBI) has been linked to the development of numerous psychiatric diseases, including substance use disorder. However, it can be difficult to ascertain from clinical data whether the TBI is cause or consequence of increased addiction vulnerability. Surprisingly few studies have taken advantage of animal models to investigate the causal nature of this relationship. In terms of a plausible neurobiological mechanism through which TBI could magnify the risk of substance dependence, numerous studies indicate that TBI can cause widespread disruption to monoaminergic signaling in striatal regions, and also increases neuroinflammation. In the current study, male Long-Evans rats received either a mild or severe TBI centered over the frontal cortex via controlled cortical impact, and were subsequently trained to self-administer cocaine over 10 6-hour sessions. At the end of the study, markers of striatal dopaminergic function, and levels of inflammatory cytokine levels in the frontal lobes, were assessed via western blot and multiplex ELISA, respectively. There was significantly higher cocaine intake in a subset of animals with either mild or severe TBI. However, many animals within both TBI groups failed to acquire self-administration. Principal components analysis suggested that both dopaminergic and neuroinflammatory proteins were associated with overall cocaine intake, yet only an inflammatory component was associated with acquisition of self-administration, suggesting neuroinflammation may make a more substantial contribution to the likelihood of drug-taking. Should neuroinflammation play a causal role in mediating TBI-induced addiction risk, anti-inflammatory therapy may reduce the likelihood of substance abuse in TBI populations.

Amantadine Did Not Positively Impact Cognition in Chronic Traumatic Brain Injury: A Multi-Site, Randomized, Controlled Trial

Despite limited evidence to support the use of amantadine to enhance cognitive function after traumatic brain injury (TBI), the clinical use for this purpose is highly prevalent and is often based on inferred belief systems. The aim of this study was to assess effect of amantadine on cognition among individuals with a history of TBI and behavioral disturbance using a parallel-group, randomized, double-blind, placebo-controlled trial of amantadine 100 mg twice-daily versus placebo for 60 days. Included in the study were 119 individuals with two or more neuropsychological measures greater than 1 standard deviation below normative means from a larger study of 168 individuals with chronic TBI (>6 months post-injury) and irritability. Cognitive function was measured at treatment days 0, 28, and 60 with a battery of neuropsychological tests. Composite indices were generated: General Cognitive Index (included all measures), a Learning Memory Index (learning/memory measures), and Attention/Processing Speed Index (attention and executive function measures). Repeated-measures analysis of variance revealed statistically significant between-group differences favoring the placebo group at day 28 for General Cognitive Index (p = 0.002) and Learning Memory Index (p = 0.001), but not Attention/Processing Speed Index (p = 0.25), whereas no statistically significant between-group differences were found at day 60. There were no statistically significant between-group differences on adverse events. Cognitive function in individuals with chronic TBI is not improved by amantadine 100 mg twice-daily. In the first 28 days of use, amantadine may impede cognitive processing. However, the effect size was small and mean scores for both groups were generally within expectations for persons with history of complicated mild-to-severe TBI, suggesting that changes observed across assessments may not have functional significance. The use of amantadine to enhance cognitive function is not supported by these findings.

Impact of Traumatic Brain Injury on Dopaminergic Transmission

Brain trauma is often associated with severe morbidity and is a major public health concern. Even when injury is mild and no obvious anatomic disruption is seen, many individuals suffer disabling neuropsychological impairments such as memory loss, mood dysfunction, substance abuse, and adjustment disorder. These changes may be related to subtle disruption of neural circuits as well as functional changes at the neurotransmitter level. In particular, there is considerable evidence that dopamine (DA) physiology in the nigrostriatal and mesocorticolimbic pathways might be impaired after traumatic brain injury (TBI). Alterations in DA levels can lead to oxidative stress and cellular dysfunction, and DA plays an important role in central nervous system inflammation. Therapeutic targeting of DA pathways may offer benefits for both neuronal survival and functional outcome after TBI. The purpose of this review is to discuss the role of DA pathology in acute TBI and the potential impact of therapies that target these systems for the treatment of TBI.

Can Amantadine Ameliorate Neurocognitive Functions After Subarachnoid Haemorrhage? A Preliminary Study

OBJECTIVE

Aneurysmal subarachnoid haemorrhage (SAH) may have devastating effects on patients. Motor and neurocognitive impairments may arise depending on the location and grade of the SAH. Although the effects of amantadine on neurocognitive function after traumatic brain injury have been widely studied to the best of our knowledge, their effects on recovery from SAH in humans have not been studied. The present study aimed to evaluate how amantadine influences improvement in neurocognitive function in patients with aneurysmal SAH over a period of six months.

METHODS

This preliminary study included 12 patients with aneurysmal SAH who were admitted to the neurointensive care unit of Cerrahpasa Faculty of Medicine. Patients in Group A (n=5) received the standard treatment for SAH and amantadine for 30 days after admission, and those in Group C (n=7) received only the standard treatment. Neurocognitive function was evaluated using the Coma Recovery Scale-Revised and Disability Rating Scale on the first and fifth days and at the third and sixth months after admission. The primary endpoint of the present study was to compare the effects of amantadine in combination with the standard treatment to those of the standard treatment alone on the neurocognitive function of patients with SAH for over 6 months.

RESULTS

Compared to the standard treatment alone, amantadine administration with the standard treatment during the early period of SAH may improve recovery.

CONCLUSION

Amantadine along with the standard treatment can ameliorate neurocognitive function after SAH.

Pharmacological Stimulation of Neuronal Plasticity in Acquired Brain Injury

INTRODUCTION

Brain injuries are one of the leading causes of disability worldwide. It is estimated that nearly half of patients who develop severe sequelae will continue with a chronic severe disability despite having received an appropriate rehabilitation program. For more than 3 decades, there has been a worldwide effort to investigate the possibility of pharmacologically stimulating the neuroplasticity process for enhancing the recovery of these patients.

OBJECTIVE

The objective of this article is to make a critical and updated review of the available evidence that supports the positive effect of different drugs on the recovery from brain injury.

METHOD

To date, there have been several clinical trials that tested different drugs that act on different neurotransmitter systems: catecholaminergic, cholinergic, serotonergic, and glutamatergic. There is both basic and clinical evidence that may support some positive effect of these drugs on motor, cognitive, and language skills; however, only few of the available studies are of sufficient methodological quality (placebo controlled, randomized, blinded, multicenter, etc) to make solid conclusions about their beneficial effects.

CONCLUSIONS

Currently, the pharmacological stimulation of neuroplasticity still does not have enough scientific evidence to make a systematic therapeutic recommendation for all patients, but it certainly is a feasible and very promising field for future research.

NMDA receptor subunit and CaMKII changes in rat hippocampus by congenital HCMV infection: a mechanism for learning and memory impairment

The aim of this study was to investigate the effects of congenital human cytomegalovirus infection on the expression levels of N-methyl-D-aspartate receptors (NRs) and Ca/calmodulin-dependent protein kinase II (CaMKII) in the hippocampal neurons of neonatal Sprague-Dawley (SD) rats. Pregnant SD rats were divided into an experimental group and a control group (n=10 in each group). Spatial learning and memory of the offspring of SD rats were evaluated using the Morris water-maze test. Pathological studies of hippocampus sections were carried out. The concentration of [Ca] was measured using a dual-wavelength spectrophotometer method. The expression levels of NRs were detected by an immunohistochemical study. Western blot was performed to detect the expression level of CaMKII. In the Morris water-maze test, the rats in the experimental group showed significantly increased escape latency and distance traveled than the control group. Damaged and structural disorders of the dentate granule in the hippocampus were found in the experimental rats. Immunohistochemistry results showed that the expression levels of NR subunits in the hippocampus of the experimental group were significantly decreased. The concentration of [Ca] in the experimental group was significantly increased. In contrast, the level of CaMKII in the experimental group was significantly decreased. The expressions of the NR subunit and CaMKII were decreased in rat hippocampus by human cytomegalovirus congenital infection, which may be associated with the mechanism underlying the impairment of learning and memory function.

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.

Missense Mutation of Brain Derived Neurotrophic Factor (BDNF) Alters Neurocognitive Performance in Patients with Mild Traumatic Brain Injury: A Longitudinal Study

The predictability of neurocognitive outcomes in patients with traumatic brain injury is not straightforward. The extent and nature of recovery in patients with mild traumatic brain injury (mTBI) are usually heterogeneous and not substantially explained by the commonly known demographic and injury-related prognostic factors despite having sustained similar injuries or injury severity. Hence, this study evaluated the effects and association of the Brain Derived Neurotrophic Factor (BDNF) missense mutations in relation to neurocognitive performance among patients with mTBI. 48 patients with mTBI were prospectively recruited and MRI scans of the brain were performed within an average 10.1 (SD 4.2) hours post trauma with assessment of their neuropsychological performance post full Glasgow Coma Scale (GCS) recovery. Neurocognitive assessments were repeated again at 6 months follow-up. The paired t-test, Cohen's d effect size and repeated measure ANOVA were performed to delineate statistically significant differences between the groups [wildtype G allele (Val homozygotes) vs. minor A allele (Met carriers)] and their neuropsychological performance across the time point (T1 = baseline/ admission vs. T2 = 6th month follow-up). Minor A allele carriers in this study generally performed more poorly on neuropsychological testing in comparison wildtype G allele group at both time points. Significant mean differences were observed among the wildtype group in the domains of memory (M = -11.44, SD = 10.0, p = .01, d = 1.22), executive function (M = -11.56, SD = 11.7, p = .02, d = 1.05) and overall performance (M = -6.89 SD = 5.3, p = .00, d = 1.39), while the minor A allele carriers showed significant mean differences in the domains of attention (M = -11.0, SD = 13.1, p = .00, d = .86) and overall cognitive performance (M = -5.25, SD = 8.1, p = .01, d = .66).The minor A allele carriers in comparison to the wildtype G allele group, showed considerably lower scores at admission and remained impaired in most domains across the timepoints, although delayed signs of recovery were noted to be significant in the domains attention and overall cognition. In conclusion, the current study has demonstrated the role of the BDNF rs6265 Val66Met polymorphism in influencing specific neurocognitive outcomes in patients with mTBI. Findings were more detrimentally profound among Met allele carriers.

Restless Legs Syndrome in a Nigerian Elderly Population

STUDY OBJECTIVES

The prevalence of restless legs syndrome (RLS) is highest in the elderly in Caucasian populations; the prevalence of RLS in elderly Africans is not known. This study aimed at determining the frequency and associations of RLS in a Nigerian elderly population.

METHODS

The study population comprised of 633 consecutive elderly individuals aged 65-105 years attending the general outpatient clinic of the State Hospital, Ilesa, for minor complaints and routine check-up. The diagnosis of RLS was made using the 2003 minimal criteria of the International Restless Legs Syndrome Study Group. Relevant sociodemographic and clinical data, including sleep duration, were also obtained.

RESULTS

Restless legs syndrome was found in 3.5% of the study population with a male-female ratio of 2:1. There was no significant age (p = 0.427) or gender (p = 0.178) influence on the prevalence of RLS except in the 75- to 84-year age group where there was significant male preponderance (p = 0.044). A strong independent association between RLS and sleep duration (OR, 3.229; 95% CI, 1.283-8.486; p = 0.013) and past history of head injury (OR, 4.691; 95% CI, 1.750-12.577; p = 0.002) was found.

CONCLUSIONS

Our finding support previous reports of a possible lower prevalence of RLS in Africans. Restless legs syndrome independently increases the odds of habitual sleep curtailment in elderly individuals. Head injury may be a risk factor for future RLS; this requires further investigation as indirect evidence for a possible link between RLS and traumatic brain injury exists.

Catecholamines and cognition after traumatic brain injury

Cognitive problems are one of the main causes of ongoing disability after traumatic brain injury. The heterogeneity of the injuries sustained and the variability of the resulting cognitive deficits makes treating these problems difficult. Identifying the underlying pathology allows a targeted treatment approach aimed at cognitive enhancement. For example, damage to neuromodulatory neurotransmitter systems is common after traumatic brain injury and is an important cause of cognitive impairment. Here, we discuss the evidence implicating disruption of the catecholamines (dopamine and noradrenaline) and review the efficacy of catecholaminergic drugs in treating post-traumatic brain injury cognitive impairments. The response to these therapies is often variable, a likely consequence of the heterogeneous patterns of injury as well as a non-linear relationship between catecholamine levels and cognitive functions. This individual variability means that measuring the structure and function of a person’s catecholaminergic systems is likely to allow more refined therapy. Advanced structural and molecular imaging techniques offer the potential to identify disruption to the catecholaminergic systems and to provide a direct measure of catecholamine levels. In addition, measures of structural and functional connectivity can be used to identify common patterns of injury and to measure the functioning of brain ‘networks’ that are important for normal cognitive functioning. As the catecholamine systems modulate these cognitive networks, these measures could potentially be used to stratify treatment selection and monitor response to treatment in a more sophisticated manner.

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.

Catecholaminergic based therapies for functional recovery after TBI

Among the many pathophysiologic consequences of traumatic brain injury are changes in catecholamines, including dopamine, epinephrine, and norepinephrine. In the context of TBI, dopamine is the one most extensively studied, though some research exploring epinephrine and norepinephrine have also been published. The purpose of this review is to summarize the evidence surrounding use of drugs that target the catecholaminergic system on pathophysiological and functional outcomes of TBI using published evidence from pre-clinical and clinical brain injury studies. Evidence of the effects of specific drugs that target catecholamines as agonists or antagonists will be discussed. Taken together, available evidence suggests that therapies targeting the catecholaminergic system may attenuate functional deficits after TBI. Notably, it is fairly common for TBI patients to be treated with catecholamine agonists for either physiological symptoms of TBI (e.g. altered cerebral perfusion pressures) or a co-occuring condition (e.g. shock), or cognitive symptoms (e.g. attentional and arousal deficits). Previous clinical trials are limited by methodological limitations, failure to replicate findings, challenges translating therapies to clinical practice, the complexity or lack of specificity of catecholamine receptors, as well as potentially counfounding effects of personal and genetic factors. Overall, there is a need for additional research evidence, along with a need for systematic dissemination of important study details and results as outlined in the common data elements published by the National Institute of Neurological Diseases and Stroke. Ultimately, a better understanding of catecholamines in the context of TBI may lead to therapeutic advancements. This article is part of a Special Issue entitled SI:Brain injury and recovery.

Care management of the agitation or aggressiveness crisis in patients with TBI. Systematic review of the literature and practice recommendations

The agitation crisis in the awakening phase after traumatic brain injury (TBI) is one of the most difficult behavioral disorders to alleviate. Current treatment options are heterogeneous and may involve excessive sedation. Practice guidelines are required by professionals in charge of TBI patients. Few reviews were published but those are old and based on expert opinions. The purpose of this work is to propose evidence-based guidelines to treat the agitation crisis.

METHODS

The elaboration of these guidelines followed the procedure validated by the French health authority for good practice recommendations, close to the Prisma statement. Guidelines were elaborated on the basis of a systematic and critical review of the literature.

RESULTS

Twenty-eight articles concerning 376 patients were analyzed. Recommendations are: when faced with an agitation crisis, the management strategy implies to search for an underlying factor that should be treated such as pain, acute sepsis, and drug adverse effect (expert opinion). Physical restraints should be discarded when possible (expert opinion). Neuroleptic agent with a marketing authorization can be used in order to obtain a quick sedation so as to protect the patient from himself, closed ones or the healthcare team but the duration should be as short as possible (expert opinion). The efficacy of beta-blockers and antiepileptics with mood regulation effects like carbamazepine and valproate yield the most compelling evidence and should be preferably used when a background regimen is envisioned (grade B for beta-blocker and C for antiepileptics). Neuroleptics, antidepressants, benzodiazepines, buspirone may be prescribed but are considered second-line treatments (expert opinion).

CONCLUSION

This study provides a strategy for treating the agitation crisis based on scientific data and expert opinion. The level of evidence remains low and published data are often old. New studies are essential to validate results from previous studies and test new drugs and non-pharmaceutical therapies.

The effectiveness of dopamine agonists for treatment of neuropsychiatric symptoms post brain injury and stroke

OBJECTIVE

Traumatic brain injury and stroke are among the leading causes of neurological disability worldwide. Although dopaminergic agents have long been associated with improvement of neuropsychiatric outcomes, to date much of the evidence to date has been in case reports and case series or open label trials.

METHODS

We undertook a systematic review of double-blinded randomised controlled trials (RCT) to determine the effect of dopaminergic agents on pre-defined outcomes of (a) apathy; (b) psychomotor retardation; (c) behavioural management and (d) cognitive function. Databases searched were: Medline, EMBASE, and PsychInfo for human studies. The Cochrane Clinical Trials Database and the TRIP Medical database were also searched. All identified studies, were further hand-searched.

RESULTS

We identified six studies providing data on 227 participants, 150 of whom received dopaminergic therapy. Trials were compromised by cross-over design, inadequate wash out period, small numbers and heterogeneous outcome measures. However one good quality RCT demonstrates the efficacy of amantadine in behavioural management. One further RCT shows methylphenidate-levodopa is efficacious for mood post-stroke. One study shows rotigotine to improve hemi-inattention caused by prefrontal damage.

CONCLUSION

Our systematic review demonstrates an evolving evidence base to suggest some benefits in agitation and aggression, mood and attentional deficits. However, there are key limitations of the studies undertaken to date involving small numbers of participants, heterogeneous outcome measures, and variable study designs. There is a need for on-going large prospective double-blind RCTs in these medications using standardised criteria and outcomes to fully understand their effectiveness in this patient group.

Dopamine Release Impairment in Striatum after Different Levels of Cerebral Cortical Fluid Percussion Injury

To investigate the role of dopamine release in cognitive impairment and motor learning deficits after brain injury, different levels of traumatic brain injury (TBI) were made in rats by using fluid percussion at two different atmospheres (2 Psi and 6 Psi). Tonic and phasic bursting dopamine release and behavior tests followed at several time points. We used in vitro fast-scan cyclic voltammetry to survey dopamine release in the striatum and analyzed the rats’ behavior using novel object recognition (NOR) and rotarod tests. Both tonic and bursting dopamine release were greatly depressed in the severely (6 Psi) injured group, which persisted up to 8 weeks later. However, in the 2 Psi-injured group, the suppression of bursting dopamine release occurred at 1~2 weeks after injury, but there were no significant differences after 4 weeks. Tonic dopamine release was also diminished significantly at 1~2 weeks after the injury; partial recovery could then be seen 4 weeks after injury. A significant deficiency in the fixed speed rotarod test and NOR test were noted in both 2 Psi and 6 Psi groups initially; however, the changes recovered in the 2 Psi group 2 weeks after injury while persisting in the 6 Psi group. In conclusion, striatal evoked dopamine release was affected by fluid percussion injury, with behavioral deficits showing differences as a function of injury severity. The severe fluid percussion injury (6 Psi) group showed more dopamine release defects, as well as cognitive and motor deficiencies. Recovery of dopamine release and improvement in behavioral impairment were better in the mild TBI group.