The effects of amantadine on traumatic brain injury outcome: a double-blind, randomized, controlled, clinical trial

Restoring consciousness with pharmacologic therapy: Mechanisms, targets, and future directions

Severe brain injury impairs consciousness by disrupting a broad spectrum of neurotransmitter systems. Emerging evidence suggests that pharmacologic modulation of specific neurotransmitter systems, such as dopamine, promotes recovery of consciousness. Clinical guidelines now endorse the use of amantadine in individuals with traumatic disorders of consciousness (DoC) based on level 1 evidence, and multiple neurostimulants are used off-label in clinical practice, including methylphenidate, modafinil, bromocriptine, levodopa, and zolpidem. However, the relative contributions of monoaminergic, glutamatergic, cholinergic, GABAergic, and orexinergic neurotransmitter systems to recovery of consciousness after severe brain injury are unknown, and personalized approaches to targeted therapy have yet to be developed. This review summarizes the state-of-the-science in the neurochemistry and neurobiology of neurotransmitter systems involved in conscious behaviors, followed by a discussion of how pharmacologic therapies may be used to modulate these neurotransmitter systems and promote recovery of consciousness. We consider pharmacologic modulation of consciousness at the synapse, circuit, and network levels, with a focus on the mesocircuit model that has been proposed to explain the consciousness-promoting effects of various monoaminergic, glutamatergic, and paradoxically, GABAergic therapies. Though fundamental questions remain about neurotransmitter mechanisms, target engagement and optimal therapy selection for individual patients, we propose that pharmacologic therapies hold great promise to promote recovery and improve quality of life for patients with severe brain injuries.

Amantadine for Traumatic Brain Injury-Supporting Evidence and Mode of Action

Traumatic brain injury (TBI) is an important global clinical issue, requiring not only prevention but also effective treatment. Following TBI, diverse parallel and intertwined pathological mechanisms affecting biochemical, neurochemical, and inflammatory pathways can have a severe impact on the patient's quality of life. The current review summarizes the evidence for the utility of amantadine in TBI in connection to its mechanism of action. Amantadine, the drug combining multiple mechanisms of action, may offer both neuroprotective and neuroactivating effects in TBI patients. Indeed, the use of amantadine in TBI has been encouraged by several clinical practice guidelines/recommendations. Amantadine is also available as an infusion, which may be of particular benefit in unconscious patients with TBI due to immediate delivery to the central nervous system and the possibility of precise dosing. In other situations, orally administered amantadine may be used. There are several questions that remain to be addressed: can amantadine be effective in disorders of consciousness requiring long-term treatment and in combination with drugs approved for the treatment of TBI? Do the observed beneficial effects of amantadine extend to disorders of consciousness due to factors other than TBI? Well-controlled clinical studies are warranted to ultimately confirm its utility in the TBI and provide answers to these questions.

Amantadine as an Aid to Extubation in Severe Acute Brain Injury: A Case Series

For a subset of patients with severe acute brain injury (SABI) undergoing invasive mechanical ventilation, the primary barrier to successful extubation is depressed mental status. Amantadine is a neurostimulant that has been demonstrated to increase arousal and improve functional outcomes in patients with SABI. In this case series, we describe 5 patients with SABI and invasive mechanical ventilation who received amantadine as an agent to improve mental status to allow extubation. The primary barrier to extubation for all patients was depressed mental status. Median age was 77 (range 32 to 82). Primary diagnoses were ischemic stroke (n = 1), subdural hemorrhage (n = 2), intracerebral hemorrhage (n = 1), and traumatic brain injury (n = 1). Median Glasgow Coma Score was 7T prior to administration of amantadine and 10T on the day after amantadine was initiated, with improvements in eye-opening and motor response. Four patients displayed improvement in arousal and attention and were successfully extubated 1 to 4 days after initiation of amantadine (median 2 days). The fifth patient only displayed marginal improvement in mental status after starting amantadine, but was ultimately able to be extubated 7 days later. Amantadine may improve the likelihood of or reduce the time to successful extubation in patients with SABI.

Advances in Neurorehabilitation: Strategies and Outcomes for Traumatic Brain Injury Recovery

Traumatic brain injury (TBI) consists of an external physical force that causes brain function impairment or pathology and globally affects 50 million people each year, with a cost of 400 billion US dollars. Clinical presentation of TBI can occur in many forms, and patients usually require prolonged hospital care and lifelong rehabilitation, which leads to an impact on the quality of life. For this narrative review, no particular method was used to extract data. With the aid of health descriptors and Medical Subject Heading (MeSH) terms, a search was thoroughly conducted in databases such as PubMed and Google Scholar. After the application of exclusion and inclusion criteria, a total of 146 articles were effectively used for this review. Results indicate that rehabilitation after TBI happens through neuroplasticity, which combines neural regeneration and functional reorganization. The role of technology, including artificial intelligence, virtual reality, robotics, computer interface, and neuromodulation, is to impact rehabilitation and life quality improvement significantly. Pharmacological intervention, however, did not result in any benefit when compared to standard care and still needs further research. It is possible to conclude that, given the high and diverse degree of disability associated with TBI, rehabilitation interventions should be precocious and tailored according to the individual's needs in order to achieve the best possible results. An interdisciplinary patient-centered care health team and well-oriented family members should be involved in every stage. Lastly, strategies must be adequate, well-planned, and communicated to patients and caregivers to attain higher functional outcomes.

The effect of amantadine treatment on neurological outcome and mortality in mechanically ventilated severe head trauma patients in intensive care unit

This study aims to investigate the effect of amantadine use on neurological outcomes and mortality in patients with severe traumatic brain injury (TBI) (Glasgow coma score [GCS] between 3 and 8) who have been followed up on mechanical ventilators in the intensive care unit (ICU). Data from the hospital's electronic records were retrospectively searched. Patients over 18 years of age, with severe brain trauma (GCS between 3-8), who were treated with endotracheal intubation and invasive mechanical ventilation at admission to the ICU, and who were treated with Amantadine hydrochloride at least once in the first week of follow-up were included in the study. To evaluate the patients' neurological outcomes, the GCS and FOUR scores were used. GCS and FOUR scores were recorded on the 1st, 3rd, and 7th days of the first week. In addition, the score difference between the 1st and 7th day was calculated for both scores. The patients were divided into 2 groups: those receiving amantadine treatment (Group A, n = 44) and the control group (Group C, n = 47). The median age of all patients was 39 (18-81) (P = .425). When Group A and Group C were compared, no statistically significant results were found between the 1st, 3rd, and 7th day GCS values (P = .474, P = .483, and P = 329, respectively). However, the difference in GCS values between day 1 and day 7 (∆ GCS 7-1) was statistically significant (P = .012). Similarly, when Group A and Group C were compared, no statistically significant results were found between the 1st, 3rd, and 7th day FOUR score values (P = .948, P = .471, and P = .057, respectively). However, the FOUR score values between day 1 and day 7 (∆ FOUR score 7-1) were statistically significant (P = .004). There was no statistically significant difference among the groups in terms of ICU length of stay, duration of non-ICU hospital stay, and length of hospital stay (P = .222, P = .175, and P = .067, respectively). Amantadine hydrochloride may help improve neurological outcomes in patients with severe TBI. However, further research is needed to investigate this topic.

A bridge to recovery: Acute amantadine prior to environmental enrichment after brain trauma augments cognitive benefit

Environmental enrichment (EE) facilitates motor and cognitive recovery after traumatic brain injury (TBI). Historically, EE has been provided immediately and continuously after TBI, but this paradigm does not model the clinic where rehabilitation is typically not initiated until after critical care. Yet, treating TBI early may facilitate recovery. Hence, we sought to provide amantadine (AMT) as a bridge therapy before commencing EE. It was hypothesized that bridging EE with AMT would augment motor and cognitive benefits. Anesthetized adult male rats received a cortical impact (2.8 mm deformation at 4 m/s) or sham surgery and then were housed in standard (STD) conditions where they received intraperitoneal AMT (10 mg/kg or 20 mg/kg) or saline vehicle (VEH; 1 mL/kg) beginning 24 h after surgery and once daily during the 6-day bridge phase or once daily for 19 days for the non-bridge groups (i.e., continuously STD-housed) to compare the effects of acute AMT plus EE vs. chronic AMT alone. Abbreviated EE, which was presented to closer emulate clinical rehabilitation (e.g., 6 h/day), began on day 7 for the AMT bridge and chronic EE groups. Motor (beam-walking) and cognition (acquisition of spatial learning and memory) were assessed on days 7-11 and 14-19, respectively. Cortical lesion volume and hippocampal cell survival were quantified on day 21. EE, whether provided in combination with VEH or AMT, and AMT (20 mg/kg) + STD, benefitted motor and cognition vs. the STD-housed VEH and AMT (10 mg/kg) groups (p < 0.05). The AMT (20 mg/kg) + EE group performed better than the VEH + EE, AMT (10 mg/kg) + EE, and AMT (20 mg/kg) + STD groups in the acquisition of spatial learning (p < 0.05) but did not differ in motor function (p > 0.05). All groups receiving EE exhibited decreased cortical lesion volumes and increased CA3 neuron survival relative to the STD-housed groups (p < 0.05) but did not differ from one another (p > 0.05). The added cognitive benefit achieved by bridging EE with AMT (20 mg/kg) supports the hypothesis that the temporal separation of combinational therapies is more effective after TBI.

The effect of amantadine on acute cognitive disability after severe traumatic brain injury: An institutional pilot study

BACKGROUND

Amantadine is used in the post-acute care setting to improve cognitive function after a traumatic brain injury. Its utility in the acute postinjury period is unknown. In this pilot study, we sought to examine the effect of amantadine on short-term cognitive disability among patients with a severe traumatic brain injury and hypothesized that patients receiving amantadine would have a greater improvement in disability throughout their acute hospitalization.

METHODS

We performed a prospective, observational study of patients ≥18 years with severe traumatic brain injury (Glasgow Coma Scale ≤8) at a level I trauma center between 2020 and 2022. Patients with penetrating trauma, death within 48 hours of admission, and no radiographic evidence of intracranial pathology were excluded. Patients were grouped according to whether they received amantadine. Our primary outcome was the change in cognitive disability, measured by the Disability Rating Scale (DRS), over the index hospitalization.

RESULTS

There were 55 patients in the cohort: 41.8% (n = 23) received amantadine and 58.2% (n = 32) did not. There were higher rates of motor vehicle collisions (65.2% vs 46.9%, P = .02), diffuse axonal injury (47.8% vs 18.8%, P = .02), intracranial pressure monitor use (73.9% vs 21.9%, P = .0001), and propranolol use (73.9% vs 21.9%, P = .0001) in the amantadine. There was a larger improvement in DRS scores among patients receiving amantadine (7.8 vs 3.6, P = .001), and amantadine independently predicted improvement in DRS scores (β, 1.61; 95% confidence interval, 0.20-3.02, P = .03). Rates of discharge to traumatic brain injury rehabilitation were significantly higher in the amantadine group (73.9% vs 21.9%, P = .0002).

CONCLUSION

Among patients with severe traumatic brain injury, amantadine use in the acute postinjury period may be associated with an improvement in cognitive disability and discharge to traumatic brain injury rehabilitation.

Amantadine for functional improvement in patients with traumatic brain injury: A systematic review with meta-analysis and trial sequential analysis

Introduction

TBIs contribute in over one-third of injury-related deaths with mortality rates as high as 50% in trauma centers serving the most severe TBI. The effect of TBI on mortality is about 10% across all ages. Amantadine hydrochloride is one of the most commonly prescribed medications for patients undergoing inpatient neurorehabilitation who have disorders of consciousness.6 It is a dopamine (DA) receptor agonist and a N-Methyl-D-aspartate (NMDA) receptor antagonist via dopamine release and dopamine reuptake inhibition. The current study will synthesize the current available evidence and show the effect of Amantadine in functional improvement after TBI.

Research question

Does Amantadine have an effect on functional improvement of TBI patients?

Material and methods

This systematic review included all randomized placebo-controlled trials that compare the use of Amantadine versus placebo for functional improvement of patients after TBI. Outcome measures included DRS, GCS and/or GOS scores.

Results

Three studies with a total of 281 patients were included in the quantitative analyses. GRADE assessments show that there was a high certainty of evidence for functional improvement in terms of DRS scores.

Discussion and conclusion

Evidence of this review show that the use of Amantadine may have a beneficial effect on functional outcome in moderate to severe traumatic brain injuries among adult patients. Given the still-limited body of knowledge, more relevant studies must be made exploring the impact of Amantadine therapies on promoting functional recovery within the brain injury rehabilitation care continuum, with the goals of achieving larger sample sizes and establishing the early- or later-treatment beneficial effects.

Pharmacology in Treatment of Patients with Disorders of Consciousness

Pharmacologic treatment of disorders of consciousness remains a critical but challenging task for clinicians. Amantadine has been shown to promote the rate of neurologic recovery for patients with traumatic disorders of consciousness when administered between 4 and 16 weeks, as demonstrated by a well-designed randomized control trial. While there are no large, randomized controlled trials to support the use of other dopaminergic medicines (bromocriptine, levodopa, apomorphine), there is a large body of literature implicating their role in improving alertness and responsiveness in disorders of consciousness. Zolpidem can increase the level of consciousness in a small subset of patients. Zolpidem and intrathecal baclofen likely increase the level of consciousness via the mesocircuit pathway. Psychostimulant medications can be initiated in patients, even without strong evidence to support their use, as long as basic principles of brain injury medicine are followed, and there are systems in place to evaluate therapeutic response.

Consciousness Recovery in Traumatic Brain Injury: A Systematic Review Comparing Modafinil and Amantadine

OBJECTIVES

Acute traumatic brain injury is one of the most common causes of death and disability. Reduction in the level of consciousness is a significant complication that can impact morbidity. Glasgow Coma Scale (GCS) is the most widely used method of assessing the level of consciousness. Neurostimulants such as amantadine and modafinil are common pharmacologic agents that increase GCS in patients with brain trauma. This study aimed to compare the effectiveness of these 2 drugs.

METHODS

This systematic review obtained articles from Google Scholar, PubMed, Scopus, Embase, and MEDLINE databases. Extensive searches were conducted separately by 4 individuals in 3 stages. Ultimately, 16 clinical trials, cohort studies, case reports, and case series articles were obtained after reading the title, abstract, and full text and considering the exclusion criteria. The data of the final article were entered into the analysis table. This study was registered with PROSPERO (registration number CRD42022334409) and conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Amantadine seems to be associated with a higher overall response rate. In contrast, modafinil is associated with the most remarkable change in GCS score during treatment. However, the number of clinical trials with high quality and sample size has not been satisfactory to compare the effectiveness of these 2 drugs and their potential side effects.

CONCLUSIONS

The authors recommend additional double-blind clinical trials are needed to be conducted with a larger sample size, comparing amantadine with modafinil to delineate the efficacy and adverse effects, both short and long term.

A placebo-controlled randomized clinical trial of amantadine hydrochloride for evaluating the functional improvement of patients following severe acute traumatic brain injury

BACKGROUND

Considering the known derangements in the dopaminergic neurotransmitter systems following traumatic brain injury (TBI), dopamine agonists are used as a pharmacologic option. In this study, we evaluate the effects of amantadine hydrochloride on the functional improvement of severe TBI patients.

METHODS

Within a triple-blinded (patients, intervention administrators, and outcome assessors) placebo-controlled randomized clinical trial, we evaluated the effects of amantadine (100 mg BD (twice a day) for 14 days, then 150 mg BD for another 7 days, and 200 mg BD for another 21 days) on outcome measurements of weekly mean Glasgow Outcome Scale (GOS) and Disability Rating Scale (DRS), through six weeks of trial for 57 patients (29 amantadine, 28 placeboes) with severe TBI admitted in our hospital.

RESULTS

Although both groups had improvement in their DRS, the change from baseline was significantly better in the amantadine group (10.88±5.24 for amantadine vs. 8.04±4.07 for placebo, P=0.015). No significant difference was observed between groups for GOS (1.04±0.55 for amantadine vs. 1.12±1.05 for placebo, P=0.966).

CONCLUSIONS

Based on our findings, amantadine hydrochloride might improve the speed of functional ability improvement in severe TBI patients, evaluated by DRS, and is also well tolerated by patients. Although, there were some limitations in this study, including small sample size, short time interval, not providing a wash-off period and invalidity of GOS for measuring recovery rates in short-term periods.

Prognostication in Prolonged and Chronic Disorders of Consciousness

Patients with prolonged disorders of consciousness (DOCs) longer than 28 days may continue to make significant gains and achieve functional recovery. Occasionally, this recovery trajectory may extend past 3 (for nontraumatic etiologies) and 12 months (for traumatic etiologies) into the chronic period. Prognosis is influenced by several factors including state of DOC, etiology, and demographics. There are several testing modalities that may aid prognostication under active investigation including electroencephalography, functional and anatomic magnetic resonance imaging, and event-related potentials. At this time, only one treatment (amantadine) has been routinely recommended to improve functional recovery in prolonged DOC. Given that some patients with prolonged or chronic DOC have the potential to recover both consciousness and functional status, it is important for neurologists experienced in prognostication to remain involved in their care.

Amantadine for NeuroenhaNcement in acutE patients Study - a protocol for a prospective pilot proof of concept phase IIb study in intensive and intermediate care unit patients (ANNES)

BACKGROUND

Persisting coma is a common complication in (neuro)intensive care in neurological disease such as acute ischemic stroke, intracerebral hemorrhage or subarachnoid hemorrhage. Amantadine acts as a nicotinic receptor antagonist, dopamine receptor agonist and non-competitive N-Methyl-D-aspartate receptor antagonist. Amantadine is a long-known drug, originally approved for treatment of influenza A and Parkinson`s Disease. It has been proven effective in improving vigilance after traumatic brain injury. The underlying mechanisms remain largely unknown, albeit anti-glutamatergic and dopaminergic effects might be most relevant. With limited evidence of amantadine efficacy in non-traumatic pathologies, the aim of our study is to assess the effects of amantadine for neuroenhancement in non-traumatic neurointensive patients with persisting coma.

METHODS

An investigator-initiated, monocenter, phase IIb proof of concept open-label pilot study will be carried out. Based on the Simon design, 43 adult (neuro)intensive care patients who meet the clinical criteria of persisting coma not otherwise explained and < 8 points on the Glasgow Coma Scale (GCS) will be recruited. Amantadine will be administered intravenously for five days at a dosage of 100 mg bid. The primary endpoint is an improvement of at least 3 points on the GCS. If participants present as non-responders (increase < 3 points or decrease on the GCS) within the first 48 h, the dosage will be doubled from day three to five. Secondary objectives aim to demonstrate that amantadine improves vigilance via alternative scales. Furthermore, the incidence of adverse events will be investigated and electroencephalography (EEG) will be recorded at baseline and end of treatment.

DISCUSSION

The results of our study will help to systematically assess the clinical utility of amantadine for treatment of persisting coma in non-traumatic brain injury. We expect that, in the face of only moderate treatment risk, a relevant number of patients will benefit from amantadine medication by improved vigilance (GCS increase of at least 3 points) finally leading to a better rehabilitation potential and improved functional neurological outcome. Further, the EEG data will allow evaluation of brain network states in relation to vigilance and potentially outcome prediction in this study cohort.

TRIAL REGISTRATION

NCT05479032.

Therapy of traumatic brain injury by modern agents and traditional Chinese medicine

Traumatic brain injury (TBI) is the leading cause of disability and death, and the social burden of mortality and morbidity caused by TBI is significant. Under the influence of comprehensive factors, such as social environment, lifestyle, and employment type, the incidence of TBI continues to increase annually. Current pharmacotherapy of TBI mainly focuses on symptomatic supportive treatment, aiming to reduce intracranial pressure, ease pain, alleviate irritability, and fight infection. In this study, we summarized numerous studies covering the use of neuroprotective agents in different animal models and clinical trials after TBI. However, we found that no drug has been approved as specifically effective for the treatment of TBI. Effective therapeutic strategies for TBI remain an urgent need, and attention is turning toward traditional Chinese medicine. We analyzed the reasons why existing high-profile drugs had failed to show clinical benefits and offered our views on the research of traditional herbal medicine for treating TBI.

INCOG 2.0 Guidelines for Cognitive Rehabilitation Following Traumatic Brain Injury, Part II: Attention and Information Processing Speed

INTRODUCTION

Moderate to severe traumatic brain injury (MS-TBI) commonly causes disruption in aspects of attention due to its diffuse nature and injury to frontotemporal and midbrain reticular activating systems. Attentional impairments are a common focus of cognitive rehabilitation, and increased awareness of evidence is needed to facilitate informed clinical practice.

METHODS

An expert panel of clinicians/researchers (known as INCOG) reviewed evidence published from 2014 and developed updated guidelines for the management of attention in adults, as well as a decision-making algorithm, and an audit tool for review of clinical practice.

RESULTS

This update incorporated 27 studies and made 11 recommendations. Two new recommendations regarding transcranial stimulation and an herbal supplement were made. Five were updated from INCOG 2014 and 4 were unchanged. The team recommends screening for and addressing factors contributing to attentional problems, including hearing, vision, fatigue, sleep-wake disturbance, anxiety, depression, pain, substance use, and medication. Metacognitive strategy training focused on everyday activities is recommended for individuals with mild-moderate attentional impairments. Practice on de-contextualized computer-based attentional tasks is not recommended because of lack of evidence of generalization, but direct training on everyday tasks, including dual tasks or dealing with background noise, may lead to gains for performance of those tasks. Potential usefulness of environmental modifications is also discussed. There is insufficient evidence to support mindfulness-based meditation, periodic alerting, or noninvasive brain stimulation for alleviating attentional impairments. Of pharmacological interventions, methylphenidate is recommended to improve information processing speed. Amantadine may facilitate arousal in comatose or vegetative patients but does not enhance performance on attentional measures over the longer term. The antioxidant Chinese herbal supplement MLC901 (NeuroAiD IITM) may enhance selective attention in individuals with mild-moderate TBI.

CONCLUSION

Evidence for interventions to improve attention after TBI is slowly growing. However, more controlled trials are needed, especially evaluating behavioral or nonpharmacological interventions for attention.

INCOG 2.0 Guidelines for Cognitive Rehabilitation Following Traumatic Brain Injury: Methods, Overview, and Principles

INTRODUCTION

Moderate to severe traumatic brain injury (TBI) results in complex cognitive sequelae. Despite hundreds of clinical trials in cognitive rehabilitation, the translation of these findings into clinical practice remains a challenge. Clinical practice guidelines are one solution. The objective of this initiative was to reconvene the international group of cognitive researchers and clinicians (known as INCOG) to develop INCOG 2.0: Guidelines for Cognitive Rehabilitation Following TBI.

METHODS

The guidelines adaptation and development cycle was used to update the recommendations and derive new ones. The team met virtually and reviewed the literature published since the original INCOG (2014) to update the recommendations and decision algorithms. The team then prioritized the recommendations for implementation and modified the audit tool accordingly to allow for the evaluation of adherence to best practices.

RESULTS

In total, the INCOG update contains 80 recommendations (25 level A, 15 level B, and 40 level C) of which 27 are new. Recommendations developed for posttraumatic amnesia, attention, memory, executive function and cognitive-communication are outlined in other articles, whereas this article focuses on the overarching principles of care for which there are 38 recommendations pertaining to: assessment (10 recommendations), principles of cognitive rehabilitation (6 recommendations), medications to enhance cognition (10 recommendations), teleassessment (5 recommendations), and telerehabilitation intervention (7 recommendations). One recommendation was supported by level A evidence, 7 by level B evidence, and all remaining recommendations were level C evidence. New to INCOG are recommendations for telehealth-delivered cognitive assessment and rehabilitation. Evidence-based clinical algorithms and audit tools for evaluating the state of current practice are also provided.

CONCLUSIONS

Evidence-based cognitive rehabilitation guided by these recommendations should be offered to individuals with TBI. Despite the advancements in TBI rehabilitation research, further high-quality studies are needed to better understand the role of cognitive rehabilitation in improving patient outcomes after TBI.

Clinical Decision on Disorders of Consciousness After Acquired Brain Injury: Stepping Forward

Major advances have been made over the past few decades in identifying and managing disorders of consciousness (DOC) in patients with acquired brain injury (ABI), bringing the transformation from a conceptualized definition to a complex clinical scenario worthy of scientific exploration. Given the continuously-evolving framework of precision medicine that integrates valuable behavioral assessment tools, sophisticated neuroimaging, and electrophysiological techniques, a considerably higher diagnostic accuracy rate of DOC may now be reached. During the treatment of patients with DOC, a variety of intervention methods are available, including amantadine and transcranial direct current stimulation, which have both provided class II evidence, zolpidem, which is also of high quality, and non-invasive stimulation, which appears to be more encouraging than pharmacological therapy. However, heterogeneity is profoundly ingrained in study designs, and only rare schemes have been recommended by authoritative institutions. There is still a lack of an effective clinical protocol for managing patients with DOC following ABI. To advance future clinical studies on DOC, we present a comprehensive review of the progress in clinical identification and management as well as some challenges in the pathophysiology of DOC. We propose a preliminary clinical decision protocol, which could serve as an ideal reference tool for many medical institutions.

Effect of drug therapy on nerve repair of moderate-severe traumatic brain injury: A network meta-analysis

Objective: This network meta-analysis aimed to explore the effect of different drugs on mortality and neurological improvement in patients with traumatic brain injury (TBI), and to clarify which drug might be used as a more promising intervention for treating such patients by ranking.

Methods: We conducted a comprehensive search from PubMed, Medline, Embase, and Cochrane Library databases from the establishment of the database to 31 January 2022. Data were extracted from the included studies, and the quality was assessed using the Cochrane risk-of-bias tool. The primary outcome measure was mortality in patients with TBI. The secondary outcome measures were the proportion of favorable outcomes and the occurrence of drug treatment–related side effects in patients with TBI in each drug treatment group. Statistical analyses were performed using Stata v16.0 and RevMan v5.3.0.

Results: We included 30 randomized controlled trials that included 13 interventions (TXA, EPO, progesterone, progesterone + vitamin D, atorvastatin, beta-blocker therapy, Bradycor, Enoxaparin, Tracoprodi, dexanabinol, selenium, simvastatin, and placebo). The analysis revealed that these drugs significantly reduced mortality in patients with TBI and increased the proportion of patients with favorable outcomes after TBI compared with placebo. In terms of mortality after drug treatment, the order from the lowest to the highest was progesterone + vitamin D, beta-blocker therapy, EPO, simvastatin, Enoxaparin, Bradycor, Tracoprodi, selenium, atorvastatin, TXA, progesterone, dexanabinol, and placebo. In terms of the proportion of patients with favorable outcomes after drug treatment, the order from the highest to the lowest was as follows: Enoxaparin, progesterone + vitamin D, atorvastatin, simvastatin, Bradycor, EPO, beta-blocker therapy, progesterone, Tracoprodi, TXA, selenium, dexanabinol, and placebo. In addition, based on the classification of Glasgow Outcome Scale (GOS) scores after each drug treatment, this study also analyzed the three aspects of good recovery, moderate disability, and severe disability. It involved 10 interventions and revealed that compared with placebo treatment, a higher proportion of patients had a good recovery and moderate disability after treatment with progesterone + vitamin D, Bradycor, EPO, and progesterone. Meanwhile, the proportion of patients with a severe disability after treatment with progesterone + vitamin D and Bradycor was also low.

Conclusion: The analysis of this study revealed that in patients with TBI, TXA, EPO, progesterone, progesterone + vitamin D, atorvastatin, beta-blocker therapy, Bradycor, Enoxaparin, Tracoprodi, dexanabinol, selenium, and simvastatin all reduced mortality and increased the proportion of patients with favorable outcomes in such patients compared with placebo. Among these, the progesterone + vitamin D had not only a higher proportion of patients with good recovery and moderate disability but also a lower proportion of patients with severe disability and mortality. However, whether this intervention can be used for clinical promotion still needs further exploration.

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.

Therapeutic Neuromodulation toward a Critical State May Serve as a General Treatment Strategy

Brain disease has become one of this century’s biggest health challenges, urging the development of novel, more effective treatments. To this end, neuromodulation represents an excellent method to modulate the activity of distinct neuronal regions to alleviate disease. Recently, the medical indications for neuromodulation therapy have expanded through the adoption of the idea that neurological disorders emerge from deficits in systems-level structures, such as brain waves and neural topology. Connections between neuronal regions are thought to fluidly form and dissolve again based on the patterns by which neuronal populations synchronize. Akin to a fire that may spread or die out, the brain’s activity may similarly hyper-synchronize and ignite, such as seizures, or dwindle out and go stale, as in a state of coma. Remarkably, however, the healthy brain remains hedged in between these extremes in a critical state around which neuronal activity maneuvers local and global operational modes. While it has been suggested that perturbations of this criticality could underlie neuropathologies, such as vegetative states, epilepsy, and schizophrenia, a major translational impact is yet to be made. In this hypothesis article, we dissect recent computational findings demonstrating that a neural network’s short- and long-range connections have distinct and tractable roles in sustaining the critical regime. While short-range connections shape the dynamics of neuronal activity, long-range connections determine the scope of the neuronal processes. Thus, to facilitate translational progress, we introduce topological and dynamical system concepts within the framework of criticality and discuss the implications and possibilities for therapeutic neuromodulation guided by topological decompositions.

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.

Pharmacologic Therapies to Promote Recovery of Consciousness

Pharmacologic interventions are commonly used to support rehabilitation efforts of patients with disorders of consciousness (DoC). The 2018 practice guidelines recommend amantadine in adults with traumatic DoC to promote functional recovery, though several other stimulants are used off-label in clinical practice and trials, such as methylphenidate, bromocriptine, levodopa, and zolpidem. Differences in the mechanisms of action, adverse effects, pharmacokinetics, and drug-drug interactions should be considered when selecting the best agent for each individual patient. Overall, pharmacologic stimulants may provide a safe and inexpensive pathway to increased functionality and participation in rehabilitation. This article provides a concise summary of scientific evidence supporting the use of pharmacologic therapies to stimulate recovery of consciousness in patients with DoC.

Methodological aspects of studying the mechanisms of consciousness

There are at least two approaches to the definition of consciousness. In the first case, certain aspects of consciousness, called qualia, are considered inaccessible for research from a third person and can only be described through subjective experience. This approach is inextricably linked with the so-called "hard problem of consciousness", that is, the question of why consciousness has qualia or how any physical changes in the environment can generate subjective experience. With this approach, some aspects of consciousness, by definition, cannot be explained on the basis of external observations and, therefore, are outside the scope of scientific research. In the second case, a priori constraints do not constrain the field of scientific investigation, and the best explanation of the experience in the first person is included as a possible subject of empirical research. Historically, in the study of cause-and-effect relationships in biology, it was customary to distinguish between proximate causation and ultimate causation existing in biological systems. Immediate causes are based on the immediate influencing factors [1]. Proximate causation has evolutionary explanations. When studying biological systems themselves, such an approach is undoubtedly justified, but it often seems insufficient when studying the interaction of consciousness and the brain [2,3]. Current scientific communities proceed from the assumption that the physical substrate for the generation of consciousness is a neural network that unites various types of neurons located in various brain structures. Many neuroscientists attach a key role in this process to the cortical and thalamocortical neural networks. This question is directly related to experimental and clinical research in the field of disorder of consciousness. Progress in this area of medicine depends on advances in neuroscience in this area and is also a powerful source of empirical information. In this area of consciousness research, a large amount of experimental data has been accumulated, and in this review an attempt was made to generalize and systematize.

The Curing Coma Campaign International Survey on Coma Epidemiology, Evaluation, and Therapy (COME TOGETHER)

Background

Although coma is commonly encountered in critical care, worldwide variability exists in diagnosis and management practices. We aimed to assess variability in coma definitions, etiologies, treatment strategies, and attitudes toward prognosis.

Methods

As part of the Neurocritical Care Society Curing Coma Campaign, between September 2020 and January 2021, we conducted an anonymous, international, cross-sectional global survey of health care professionals caring for patients with coma and disorders of consciousness in the acute, subacute, or chronic setting. Survey responses were solicited by sequential emails distributed by international neuroscience societies and social media. Fleiss κ values were calculated to assess agreement among respondents.

Results

The survey was completed by 258 health care professionals from 41 countries. Respondents predominantly were physicians (n = 213, 83%), were from the United States (n = 141, 55%), and represented academic centers (n = 231, 90%). Among eight predefined items, respondents identified the following cardinal features, in various combinations, that must be present to define coma: absence of wakefulness (81%, κ = 0.764); Glasgow Coma Score (GCS) ≤ 8 (64%, κ = 0.588); failure to respond purposefully to visual, verbal, or tactile stimuli (60%, κ = 0.552); and inability to follow commands (58%, κ = 0.529). Reported etiologies of coma encountered included medically induced coma (24%), traumatic brain injury (24%), intracerebral hemorrhage (21%), and cardiac arrest/hypoxic-ischemic encephalopathy (11%). The most common clinical assessment tools used for coma included the GCS (94%) and neurological examination (78%). Sixty-six percent of respondents routinely performed sedation interruption, in the absence of contraindications, for clinical coma assessments in the intensive care unit. Advanced neurological assessment techniques in comatose patients included quantitative electroencephalography (EEG)/connectivity analysis (16%), functional magnetic resonance imaging (7%), single-photon emission computerized tomography (6%), positron emission tomography (4%), invasive EEG (4%), and cerebral microdialysis (4%). The most commonly used neurostimulants included amantadine (51%), modafinil (37%), and methylphenidate (28%). The leading determinants for prognostication included etiology of coma, neurological examination findings, and neuroimaging. Fewer than 20% of respondents reported routine follow-up of coma survivors after hospital discharge; however, 86% indicated interest in future research initiatives that include postdischarge outcomes at six (85%) and 12 months (65%).

Conclusions

There is wide heterogeneity among health care professionals regarding the clinical definition of coma and limited routine use of advanced coma assessment techniques in acute care settings. Coma management practices vary across sites, and mechanisms for coordinated and sustained follow-up after acute treatment are inconsistent. There is an urgent need for the development of evidence-based guidelines and a collaborative, coordinated approach to advance both the science and the practice of coma management globally.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12028-021-01425-8.

A Retrospective Analysis of Randomized Controlled Trials on Traumatic Brain Injury: Evaluation of CONSORT Item Adherence

Traumatic brain injury (TBI) contributes to death and disability, resulting in an enormous individual and socio-economic challenges. Despite huge efforts, there are still controversies on treatment strategies and early outcome estimation. We evaluate current randomized controlled trials (RCTs) on TBI according to their fulfillment of the CONSORT (Consolidated Statement of Reporting Trials) statement’s criteria as a marker of transparency and the quality of study planning and realization. A PubMed search for RCTs on TBI (January 2014–December 2019) was carried out. After screening of the abstracts (n = 1.926), the suitable full text manuscripts (n = 72) were assessed for the fulfillment of the CONSORT criteria. The mean ratio of consort statement fulfillment was 59% (±13%), 31% of the included studies (n = 22) complied with less than 50% of the CONSORT criteria. Citation frequency was moderately related to ratio of CONSORT item fulfillment (r = 0.4877; p < 0.0001) and citation frequency per year (r = 0.5249; p < 0.0001). The ratio of CONSORT criteria fulfillment was associated with the impact factor of the publishing journal (r = 0.6428; p < 0.0001). Essential data for study interpretation, such as sample size determination (item 7a), participant flow (item 13a) as well as losses and exclusions (item 13b), were only reported in 53%, 60% and 63%, respectively. Reporting and methodological aspects in RCTs on TBI still may be improved. Thus, the interpretation of study results may be hampered due to methodological weaknesses.

Evaluation of Outcomes in Patients Receiving Amantadine to Improve Alertness After Traumatic Brain Injury

Background: Amantadine has been used off-label to improve alertness after traumatic brain injury (TBI). The goal of this study is to assess the mean change at 72 hours and in course of therapy (COT) Glasgow Coma Scale (GCS) score after amantadine initiation and to correlate the change in GCS score with participation in physical therapy (PT) and occupational therapy (OT) among patients with TBI receiving amantadine during the first hospitalization. Methods: This single-center, retrospective, cohort study included patients ≥18 years old hospitalized for a TBI from August 2012 to February 2018 and received ≥1 dose of amantadine to increase alertness. The primary endpoint is the mean change in 72-hour GCS score after amantadine initiation. The secondary endpoint is the mean change in COT GCS score after amantadine initiation and the correlation between the change in GCS score and percent PT and OT participation at 72 hours and during the COT. Results: Seventy-nine patients were included. The mean age of patients was 41 years, and 79.8% of the patients were men. The mean change in 72-hour GCS score was +0.75 (95% confidence interval [CI] = 0.09-1.42, P = .027), and the mean change in COT GCS score was +2.29 (95% CI = 1.68-2.90, P < .001). There was no significant correlation between the increase in GCS score and percent PT/OT session participation at 72 hours and during the COT, r = -0.15 (P = .24) and r = -0.02 (P = .74), respectively. The percent PT/OT session participation at 72-hour post-amantadine initiation was 61.3% compared with 65.9% during the COT. Conclusion: There were small but statistically significant increases in the mean change at 72 hours and in COT GCS score; however, they were not correlated with percent PT/OT participation. Other studies are needed to determine the appropriate time and GCS score to initiate amantadine along with the optimal dose in the inpatient setting.

Correlation between bispectral index and prognosis of patients with acute cerebral infarction

INTRODUCTION

This study aimed to investigate the clinical value of bispectral index (BIS) monitoring in assessing the consciousness and prognosis of acute cerebral infarction (ACI) patients.

METHODS

In total, 64 patients who suffered from ACI with consciousness disturbance were enrolled in this study. Glasgow Coma Scale (GCS) was performed to evaluate the consciousness level of ACI patients, and BIS was used to monitor the depth of anesthesia and sedation. Then, patients were divided into good prognosis, poor prognosis and death groups according to modified Rankin score (mRS). Discrimination analysis of BIS values and GCS score for the prediction of prognosis was performed using the receiver operator characteristic (ROC) curve.

RESULTS

GCS score and BIS values showed statistically significant differences among the three groups. Spearman rank correlation analysis revealed a significant positive correlation between BIS values and GCS score, while BIS values was negatively related with mRS. The ROC curve of prognosis prediction showed strong prognostic power, with area under the curves (AUCs) between 0.830 and 0.917. Moreover, the AUC of BISmean score was higher than that of BISmax, BISmin and GCS, and BISmean of 74 was the best cut-off point for good prognosis.

CONCLUSION

BIS directly reflects the degree of consciousness disturbance in ACI patients, and thus accurately predicts the prognosis, indicating potential application values of BIS in clinical practice.

Safety Considerations for the Use of Transcranial Magnetic Stimulation as Treatment for Coma Recovery in People With Severe Traumatic Brain Injury

Objective:

For persons in states of disordered consciousness (DoC) after severe traumatic brain injury (sTBI), we report cumulative findings from safety examinations, including serious adverse events (AEs) of a repetitive transcranial magnetic stimulation (rTMS) parameter protocol in 2 different studies.

Participants:

Seven persons in states of DoC after sTBI with widespread neuropathology, but no large lesions in proximity to the site of rTMS. One participant had a ventriculoperitoneal shunt with programmable valve.

Methods:

Two clinical trials each providing 30 rTMS sessions to the right or left dorsolateral prefrontal cortex, involving 300 to 600 pulses over 1 or 2 sessions daily. One study provided concomitant amantadine. Safety indicators monitored related to sleep, temperature, blood pressure, skin integrity, sweating, weight loss, infections, and seizure.

Results:

Average changes for monitored indicators were of mild severity, with 75 nonserious AEs and 1 serious AE (seizure). The participant incurring a seizure resumed rTMS while taking antieplieptics without further seizure activity.

Conclusions:

Considering elevated risks for this patient population and conservative patient selection, findings indicate a relatively safe profile for the specified rTMS protocols; however, potential for seizure induction must be monitored. Future research for this population can be broadened to include patients previously excluded on the basis of profiles raising safety concerns.

Treating Traumatic Brain Injuries with Electroceuticals: Implications for the Neuroanatomy of Consciousness

According to the Centers for Disease Control and Prevention (CDC), traumatic brain injury (TBI) is the leading cause of loss of consciousness, long-term disability, and death in children and young adults (age 1 to 44). Currently, there are no United States Food and Drug Administration (FDA) approved pharmacological treatments for post-TBI regeneration and recovery, particularly related to permanent disability and level of consciousness. In some cases, long-term disorders of consciousness (DoC) exist, including the vegetative state/unresponsive wakefulness syndrome (VS/UWS) characterized by the exhibition of reflexive behaviors only or a minimally conscious state (MCS) with few purposeful movements and reflexive behaviors. Electroceuticals, including non-invasive brain stimulation (NIBS), vagus nerve stimulation (VNS), and deep brain stimulation (DBS) have proved efficacious in some patients with TBI and DoC. In this review, we examine how electroceuticals have improved our understanding of the neuroanatomy of consciousness. However, the level of improvements in general arousal or basic bodily and visual pursuit that constitute clinically meaningful recovery on the Coma Recovery Scale-Revised (CRS-R) remain undefined. Nevertheless, these advancements demonstrate the importance of the vagal nerve, thalamus, reticular activating system, and cortico-striatal-thalamic-cortical loop in the process of consciousness recovery.

Role of the Dopaminergic System in the Striatum and Its Association With Functional Recovery or Rehabilitation After Brain Injury

Disabilities are estimated to occur in approximately 2% of survivors of traumatic brain injury (TBI) worldwide, and disability may persist even decades after brain injury. Facilitation or modulation of functional recovery is an important goal of rehabilitation in all patients who survive severe TBI. However, this recovery tends to vary among patients because it is affected by the biological and physical characteristics of the patients; the types, doses, and application regimens of the drugs used; and clinical indications. In clinical practice, diverse dopaminergic drugs with various dosing and application procedures are used for TBI. Previous studies have shown that dopamine (DA) neurotransmission is disrupted following moderate to severe TBI and have reported beneficial effects of drugs that affect the dopaminergic system. However, the mechanisms of action of dopaminergic drugs have not been completely clarified, partly because dopaminergic receptor activation can lead to restoration of the pathway of the corticobasal ganglia after injury in brain structures with high densities of these receptors. This review aims to provide an overview of the functionality of the dopaminergic system in the striatum and its roles in functional recovery or rehabilitation after TBI.

Recovery from disorders of consciousness: mechanisms, prognosis and emerging therapies

Substantial progress has been made over the past two decades in detecting, predicting and promoting recovery of consciousness in patients with disorders of consciousness (DoC) caused by severe brain injuries. Advanced neuroimaging and electrophysiological techniques have revealed new insights into the biological mechanisms underlying recovery of consciousness and have enabled the identification of preserved brain networks in patients who seem unresponsive, thus raising hope for more accurate diagnosis and prognosis. Emerging evidence suggests that covert consciousness, or cognitive motor dissociation (CMD), is present in up to 15-20% of patients with DoC and that detection of CMD in the intensive care unit can predict functional recovery at 1 year post injury. Although fundamental questions remain about which patients with DoC have the potential for recovery, novel pharmacological and electrophysiological therapies have shown the potential to reactivate injured neural networks and promote re-emergence of consciousness. In this Review, we focus on mechanisms of recovery from DoC in the acute and subacute-to-chronic stages, and we discuss recent progress in detecting and predicting recovery of consciousness. We also describe the developments in pharmacological and electrophysiological therapies that are creating new opportunities to improve the lives of patients with DoC.

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.

Use of Machine Learning to Re-Assess Patterns of Multivariate Functional Recovery after Fluid Percussion Injury: Operation Brain Trauma Therapy

Traumatic brain injury (TBI) is a leading cause of death and disability. Yet, despite immense research efforts, treatment options remain elusive. Translational failures in TBI are often attributed to the heterogeneity of the TBI population and limited methods to capture these individual variabilities. Advances in machine learning (ML) have the potential to further personalized treatment strategies and better inform translational research. However, the use of ML has yet to be widely assessed in pre-clinical neurotrauma research, where data are strictly limited in subject number. To better establish ML's feasibility, we utilized the fluid percussion injury (FPI) portion of the rich, rat data set collected by Operation Brain Trauma Therapy (OBTT), which tested multiple pharmacological treatments. Previous work has provided confidence that both unsupervised and supervised ML techniques can uncover useful insights from this OBTT pre-clinical research data set. As a proof-of-concept, we aimed to better evaluate the multi-variate recovery profiles afforded by the administration of nine different experimental therapies. We assessed supervised pairwise classifiers trained on a pre-processed data set that incorporated metrics from four feature groups to determine their ability to correctly identify specific drug treatments. In all but one of the possible pairwise combinations of minocycline, levetiracetam, erythropoietin, nicotinamide, and amantadine, the baseline was outperformed by one or more supervised classifiers, the exception being nicotinamide versus amantadine. Further, when the same methods were employed to assess different doses of the same treatment, the ML classifiers had greater difficulty in understanding which treatment each sample received. Our data serve as a critical first step toward identifying optimal treatments for specific subgroups of samples that are dependent on factors such as types and severity of traumatic injuries, as well as informing the prediction of therapeutic combinations that may lead to greater treatment effects than individual therapies.

Amantadine and Modafinil as Neurostimulants Following Acute Stroke: A Retrospective Study of Intensive Care Unit Patients

Background/Objective

Neurostimulants may improve or accelerate cognitive and functional recovery after intracerebral hemorrhage (ICH), ischemic stroke (IS), or subarachnoid hemorrhage (SAH), but few studies have described their safety and effectiveness in the intensive care unit (ICU). The objective of this study was to describe amantadine and modafinil administration practices during acute stroke care starting in the ICU and to evaluate safety and effectiveness.

Methods

Consecutive adult ICU patients treated with amantadine and/or modafinil following acute non-traumatic IS, ICH, or SAH were evaluated. Neurostimulant administration data were extracted from the electronic medication administration record, including medication (amantadine, modafinil, or both), starting dose, time from stroke to initiation, and whether the neurostimulant was continued at hospital discharge. Patients were considered responders if they met two of three criteria within 9 days of neurostimulant initiation: increase in Glasgow coma scale (GCS) score ≥ 3 points from pre-treatment baseline, improved wakefulness or participation documented in caregiver notes, or clinical improvement documented in physical or occupational therapy notes. Potential confounders of the effectiveness assessment and adverse drug effects were also recorded.

Results

A total of 87 patients were evaluable during the 3.7-year study period, including 41 (47%) with ICH, 29 (33%) with IS, and 17 (20%) with SAH. The initial neurostimulant administered was amantadine in 71 (82%) patients, modafinil in 13 (15%), or both in 3 (3%) patients. Neurostimulants were initiated a median of 7 (4.25, 12.75) days post-stroke (range 1–27 days) for somnolence (77%), not following commands (32%), lack of eye opening (28%), or low GCS (17%). The most common starting dose was 100 mg twice daily for both amantadine (86%) and modafinil (54%). Of the 79 patients included in the effectiveness evaluation, 42 (53%) were considered responders, including 34/62 (55%) receiving amantadine monotherapy and 8/24 (33%) receiving both amantadine and modafinil at the time they met the definition of a responder. No patient receiving modafinil monotherapy was considered a responder. The median time from initiation to response was 3 (2, 5) days. Responders were more frequently discharged home or to acute rehabilitation compared to non-responders (90% vs 62%, p = 0.006). Among survivors, 63/72 (88%) were prescribed a neurostimulant at hospital discharge. The most common potential adverse drug effect was sleep disruption (16%).

Conclusions

Neurostimulant administration during acute stroke care may improve wakefulness. Future controlled studies with a neurostimulant administration protocol, prospective evaluation, and discretely defined response and safety criteria are needed to confirm these encouraging findings.

Electronic supplementary material

The online version of this article (10.1007/s12028-020-00986-4) contains supplementary material, which is available to authorized users.

The role of amantadine in cognitive recovery early after traumatic brain injury: A systematic review

We conducted an updated systematic review on the safety and efficacy of amantadine in cognitive recovery after traumatic brain injury (TBI), in order to determine if the current literature justifies its use in this clinical condition. A comprehensive search strategy was applied to three databases (PubMed, Scopus, and Cochrane). Only randomized clinical trials (RCTs) that compared the effect of amantadine and placebo in adults within 3 months of TBI were included in the review. Study characteristics, outcomes, and methodological quality were synthesized. This systematic review was conducted and presented in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A quantitative synthesis (meta-analysis) was not feasible due to the large heterogeneity of studies identified. Three parallel RCTs and one cross-over RCT, with a total of 325 patients were included. All of the studies evaluated only severe TBI in adults. Amantadine was found to be well tolerated across the studies. Two RCTs reported improvement in the intermediate-term cognitive recovery (four to six weeks after end of treatment), using DRS (in both studies) and MMSE, GOS, and FIM-Cog (in one study). The effect of amantadine on the short-term (seven days to discharge) and long-term (six months from the injury) cognitive outcome was found not superior to placebo in two RCTs. The rate of severe adverse events was found to be consistently very low across the studies (the incidence of seizures, elevation in liver enzymes and cardiac death was 0.7 %, 1.9 %, and 0.3 %, respectively). In conclusion, amantadine seems to be well tolerated and might hasten the rate of cognitive recovery in the intermediate-term outcome. However, the long-term effect of amantadine in cognitive recovery is not well defined and further large randomized clinical trials in refined subgroups of patients are needed to better define its application.

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.

Unilateral parietal brain injury increases risk-taking on a rat gambling task

Traumatic brain injury (TBI) affects millions of individuals every year. Many of these injuries lead to lasting effects, particularly impairments in domains broadly classified as executive functions, such as impulse control and decision-making. While these impairments have been historically associated with frontal brain damage, other injuries such as concussion or parietal injury also contribute to similar dysfunction. However, it is unknown whether animal models of TBI would replicate these broad effects that are observed in human patients. In the current study, we delivered a unilateral parietal controlled cortical impact injury and assessed the performance of rats on a motoric task (rotarod) and a test of decision-making and impulsivity (rodent gambling task). TBI rats demonstrated significant motor impairments on the rotarod task; however, this did not extend to difficulties inhibiting motor actions (impulsivity). In addition, TBI caused chronic alterations to risk-based decision-making, extending out to 12 weeks post-injury. Specifically, rats with TBI preferred the riskiest, and most suboptimal option over all others. The current data suggest that models of unilateral TBI are sufficient for replicating some aspects of executive dysfunction (risky decision-making), while others are limited to frontal damage (impulsivity). These models may be used to develop therapeutics targeted at the chronic post-injury period when these symptoms often manifest in patients, a critically understudied area in preclinical TBI research.

Efficacy and safety of cerebrolysin in neurorecovery after moderate-severe traumatic brain injury: results from the CAPTAIN II trial

INTRODUCTION

The objective of this trial was to evaluate the efficacy and safety of Cerebrolysin in treating patients after moderate to severe traumatic brain injury (TBI) as an adjunct to standard care protocols. The trial was designed to investigate the clinical effects of Cerebrolysin in the acute (neuroprotective) stage and during early and long-term recovery as part of a neurorestorative strategy.

MATERIALS AND METHODS

The study was a phase IIIb/IV single-center, prospective, randomized, double-blind, placebo-controlled clinical trial. Eligible patients with a Glasgow Coma Score (GCS) between 7 and 12 received study medication (50 ml of Cerebrolysin or physiological saline solution per day for 10 days, followed by two additional treatment cycles with 10 ml per day for 10 days) in addition to standard care. We tested ensembles of efficacy criteria for 90, 30, and 10 days after TBI with a priori ordered hypotheses using a multivariate, directional test, to reflect the global status of patients after TBI.

RESULTS

The study enrolled 142 patients, of which 139 underwent formal analysis (mean age = 47.4, mean admission GCS = 10.4, and mean Baseline Prognostic Risk Score = 2.6). The primary endpoint, a multidimensional ensemble of 13 outcome scales, indicated a "small-to-medium"-sized effect in favor of Cerebrolysin, statistically significant at day 90 (MW_combined = 0.59, 95% CI 0.52 to 0.66, P = 0.0119). Safety and tolerability observations were comparable between treatment groups.

CONCLUSION

Our trial confirms previous beneficial effects of the multimodal, biological agent Cerebrolysin for overall outcome after moderate to severe TBI, as measured by a multidimensional approach. Study findings must be appraised and aggregated in conjunction with existing literature, as to improve the overall level of insight regarding therapeutic options for TBI patients. The widely used pharmacologic intervention may benefit from a large-scale observational study to map its use and to establish comparative effectiveness in real-world clinical settings.

Recent advances in traumatic brain injury

Traumatic brain injury (TBI) is the most common cause of death and disability in those aged under 40 years in the UK. Higher rates of morbidity and mortality are seen in low-income and middle-income countries making it a global health challenge. There has been a secular trend towards reduced incidence of severe TBI in the first world, driven by public health interventions such as seatbelt legislation, helmet use, and workplace health and safety regulations. This has paralleled improved outcomes following TBI delivered in a large part by the widespread establishment of specialised neurointensive care. This update will focus on three key areas of advances in TBI management and research in moderate and severe TBI: refining neurointensive care protocolized therapies, the recent evidence base for decompressive craniectomy and novel pharmacological therapies. In each section, we review the developing evidence base as well as exploring future trajectories of TBI research.

Stimulant Therapy in Acute Traumatic Brain Injury: Prescribing Patterns and Adverse Event Rates at 2 Level 1 Trauma Centers

BACKGROUND/OBJECTIVE

Pharmacological stimulant therapies are routinely administered to promote recovery in patients with subacute and chronic disorders of consciousness (DoC). However, utilization rates and adverse drug event (ADE) rates of stimulant therapies in patients with acute DoC are unknown. We aimed to determine the frequency of stimulant use and associated ADEs in intensive care unit (ICU) patients with acute DoC caused by traumatic brain injury (TBI).

METHODS

We retrospectively identified patients with TBI admitted to the ICU at 2 level 1 trauma centers between 2015 and 2018. Patients were included if they were stimulant naive at baseline and received amantadine, methylphenidate, or modafinil during ICU admission. Stimulant dose reduction or discontinuation during ICU admission was considered a surrogate marker of an ADE. Targeted chart review was performed to identify reasons for dose reduction or discontinuation.

RESULTS

Forty-eight of 608 patients with TBI received pharmacological stimulant therapy (7.9%) during the study period. Most patients were diagnosed with severe TBI at presentation (60.4%), although stimulants were also administered to patients with moderate (14.6%) and mild (25.0%) TBI. The median time of stimulant initiation was 11 days post-injury (range: 2-28 days). Median Glasgow Coma Scale score at the time of stimulant initiation was 9 (range: 4-15). Amantadine was the most commonly prescribed stimulant (85.4%) followed by modafinil (14.6%). Seven (14.6%) patients required stimulant dose reduction or discontinuation during ICU admission. The most common ADE resulting in therapy modification was delirium/agitation (n = 2), followed by insomnia (n = 1), anxiety (n = 1), and rash (n = 1); the reason for therapy modification was undocumented in 2 patients.

CONCLUSIONS

Pharmacological stimulant therapy is infrequently prescribed but well tolerated in ICU patients with acute TBI at level 1 trauma centers. These retrospective observations provide the basis for prospective studies to evaluate the safety, optimal dose range, and efficacy of stimulant therapies in this population.

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.

Prevalence of medication and off-label medication use in acquired brain injury at a neurorehabilitation hospital

PURPOSE

Patients who suffer acquired brain injury (ABI) require a great variety of drugs. Furthermore, the lack of evidence on the medication effects in this type of patient increases off-label prescription. The aim of this study was to describe the pattern of medication use and the practice of prescribing off-label drugs in these patients.

METHODS

A cross-sectional study was conducted in patients with ABI, of either traumatic or non-traumatic cause, admitted to a neurorehabilitation hospital for rehabilitation. Demographic and clinical data and prevalence of medication use and off-label prescription were collected.

RESULTS

The majority of the studied patients (85.2%) were considered polymedicated since they were prescribed ≥ 6 drugs concomitantly. In traumatic brain injury (TBI) patients, antidepressants (81.5%) were the Anatomical Therapeutic Chemical (ATC) group's most prescribed versus antithrombotic agents (80.5%) in non-traumatic brain injury (N-TBI) patients. Up to 37.3% of all active substances prescribed in TBI patients were off-label compared with 24.9% in N-TBI patients. The most prescribed off-label active substances in both groups were those related to the Nervous System (N) ATC group to treat neurobehavioural problems.

CONCLUSION

A multidisciplinary pharmacotherapeutic follow-up of these patients would be essential to address the high prescription rate of medications and the off-label prescription practice. In this way, medication problems related to polypharmacy could be minimised and the benefit-risk ratio of prescribed off-label drugs could be ensured according to the available medical evidence.

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.

Dose-dependent neurorestorative effects of amantadine after cortical impact injury

Numerous pharmacotherapies have been evaluated after experimental traumatic brain injury (TBI). While amantadine (AMT) has shown potential for clinical efficacy, the few studies on its effectiveness have been mixed. It is possible that suboptimal dosing, due to the evaluation of only one dose, may be causing the discrepancies in outcomes. Hence, the goal of the current study was to conduct a dose response of AMT after TBI to determine an optimal behavioral benefit. Anesthetized adult male rats received either a cortical impact of moderate severity or sham injury and then were randomly assigned to receive once daily intraperitoneally injections of AMT (10, 20, or 40 mg/kg) or saline vehicle (VEH, 1 mL/kg) commencing 24 h after injury for 19 days. Motor and cognitive function were assessed on post-operative days 1-5 and 14-19, respectively. There were no statistical differences among the sham groups treated with AMT or VEH so the data were pooled. AMT (20 mg/kg) facilitated beam-balance recovery and spatial learning relative to VEH-treated controls (p < 0.05). No other doses of AMT were effective. These results indicate that dosing should be carefully considered when assessing the effects of pharmacotherapies after TBI so that potential benefits are not inadvertently missed.