Amantadine to improve neurorecovery in traumatic brain injury-associated diffuse axonal injury: a pilot double-blind randomized trial

Is there anybody in there? Detecting awareness in disorders of consciousness

The bedside detection of awareness in disorders of consciousness (DOC) caused by acquired brain injury is not an easy task. For this reason, differential diagnosis using neuroimaging and electrophysiological tools in search for objective markers of consciousness is being employed. However, such tools cannot be considered as diagnostic per se, but as assistants to the clinical evaluation, which, at present, remains the gold standard. Regarding therapeutic management in DOC, no evidence-based recommendations can be made in favor of a specific treatment. The present review summarizes clinical and paraclinical studies that have been conducted with neuroimaging and electrophysiological techniques in search of residual awareness in DOC. We discuss the medical, scientific and ethical implications that derive from these studies and we argue that, in the future, the role of neuroimaging and electrophysiology will be important not only for the diagnosis and prognosis of DOC but also in establishing communication with these challenging patients.

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

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

Neurobehavioral management of traumatic brain injury in the critical care setting

Traumatic brain injury (TBI) results in approximately 230,000 hospitalizations annually in the United States. Advances in the acute management of TBI have improved survival after TBI. Many TBI survivors develop neurobehavioral disturbances in the acute post-injury period. Neurobehavioral sequelae present clinical management challenges for critical care professionals. This article defines and describes TBI and reviews its common neuroanatomic and neurobehavioral consequences. These disturbances are organized under the framework of posttraumatic encephalopathy, and the characteristic forms and stages of recovery of this condition are discussed. Recommendations regarding evaluation and management of posttraumatic neurobehavioral problems in the critical care setting are offered.

Congenital and acquired brain injury. 4. Outpatient and community reintegration

This self-directed learning module highlights the rehabilitation aspects of care for people with traumatic brain injury (TBI) after the acute phase. It focuses on issues important to community reentry, outpatient care, and return to work. It is part of the chapter on TBI medicine in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article specifically focuses on the formulation of rehabilitation plans to address the issues of cognitive dysfunction, behavioral disturbances, and community reintegration. Topics covered include pharmacologic and nonpharmacologic approaches to cognitive and affective disorders, intimacy, social isolation, mobility, and return to work. Finally, the critical issues of legal competency and obtaining informed consent in the population with cognitive impairment are discussed.

OVERALL ARTICLE OBJECTIVE

To summarize the issues that affect outpatient care, independence, and community reentry after traumatic brain injury.

Amantadine Enhancement of Arousal and Cognition After Traumatic Brain Injury

Objective:

To determine the role of amantadine therapy tor early arousal and improved cognition in traumatic brain injury (TBI).

Data Sources:

Literature was accessed through MEDLINE (1950–August 2007) using the MeSH terms amantadine, brain injuries, cognition, and arousal. PubMed (through August 2007) terms included amantadine, traumatic brain injury, and cerebral injury.

Study Selection and Data Extraction:

All studies ol amantadine (used <6 mo after injury) for enhancement of arousal or cognition in patients with TBI were reviewed.

Data Synthesis:

Many cases of TBI are associated with frontal lobe injury. As a dopamine agonist, amantadine is thought to be involved in frontal lobe stimulation. Two case reports, 3 retrospective studies, and 2 randomized, double-blind, controlled trials of amantadine therapy for early arousal in TBI were identified and reviewed. Limitations of the available studies include open design, retrospective design, and heterogeneous brain injury types. Results have been inconsistent between studies, largely due to variability in designs, heterogeneity in patient populations, time following injury, and use of numerous different outcome measures. Despite these limitations, improvements in arousal and cognition, as documented by the Glasgow Coma Scale and olher measures, have been observed in patients with TBI when amantadine has been initiated 3 days to 5 months after injury.

Conclusions:

At doses of 200–400 mg/day, amantadine appears to safely improve arousal and cognition in patients with TBI. Additional prospective controlled studies with homogeneous patient populations will better define the role of amantadine for early arousal.

[Early neurological-neurosurgical rehabilitation. Current state]

In German neurorehabilitation, the ambiguous term "early rehabilitation" reflects the multidisciplinary, rehabilitative treatment of severely impaired patients in continuing need of acute and intensive care (including weaning from the respirator in selected cases). The actual definition of this treatment is discussed, which hitherto corresponded to Phase B according to recommendations of the German Federal Study Group for Rehabilitation (BAR) and now has started to be integrated into the diagnosis-related group system. The tasks and aims of early rehabilitation are to support and enhance neuroplastic remission of nervous system functional loss and continued medical care, improve vigilance, establish cooperativity, and evaluate the rehabilitation potential including compensatory and adaptive strategies organizing posthospital care, reducing the need of nursing support, and improving quality of life. Some special aspects of early rehabilitative care are presented here in more detail. To fulfill these tasks, a multidisciplinary team is required including various therapists qualified for neurorehabilition, physicians (including a neurologist), nurses, and social workers. Outcome data were assessed using our 5-year prospective early rehabilitation registry. Fifty-five percent of patients improved to reach the next step of neurorehabilitation (Phase C), with significant gain in function even in the subgroup of aged and most severely disabled patients. The trend to transfer patients very early in the postacute Phase to early rehabilitation facilities, with open medical problems and increased risk of complications, makes close cooperation and interaction with acute medical centers necessary.

Amantadine for adynamic speech: possible benefit for aphasia?

OBJECTIVE

Dopaminergic agents may stimulate behavior and verbal expression after frontal lobe dysfunction. Although amantadine is used in neurorehabilitation of motivational disorders and head injury, it is not commonly prescribed to improve aphasia. This pilot study examined verbal fluency on and off amantadine for nonfluent speech.

DESIGN

Four participants undergoing inpatient rehabilitation, meeting criteria for transcortical motor aphasia had stroke (2), stroke postaneurysm surgery (1), or brain tumor resection (1). We administered 100 mg of amantadine twice a day in an open-label, on-off protocol, with multiple assessments per on-off period.

RESULTS

Off medication, subjects generated a mean 12.62 of words (abnormally few) on the Controlled Oral Word Association test. On medication, word generation significantly improved to 17.71 words (P = 0.04), although scores remained psychometrically in the abnormal range.

CONCLUSIONS

Further research on amantadine, specifically for nonfluent speech and nonfluent aphasia, including effects on functional communication and control conditions, may be warranted.

Amantadine treatment of hemispatial neglect: a double-blind, placebo-controlled study

OBJECTIVE

The resemblance of some aspects of the hemispatial neglect syndrome (hypokinesia, decreased arousal) to aspects of Parkinsonian syndromes, and the success of amantadine in treating disorders of attention, prompted a placebo-controlled, double-blind trial of amantadine, an inhibitor of the N-methyl D-aspartate (NMDA) glutamate receptor that modulates dopamine transmission, in four patients with chronic hemispatial neglect.

DESIGN

Patients received placebo or 100 mg of amantadine twice a day in an ABA design. Dependent measures of drug effect included an extensive battery of tests assessing arousal, hemiinattention, hemihypokinesia, personal neglect, disability, anosognosia, family burden, and naturalistic action.

RESULTS

There was no evidence of increased adverse effects with the treatment drug compared with placebo. Of the 17 measures used to assess treatment response in the four patients (68 measures total), linear regressions revealed significant positive treatment effects on very few (four) measures (uncorrected for multiple comparisons), and scattered negative responses to treatment were evident on three measures. The vast majority of measures showed no change in response to treatment.

CONCLUSIONS

Possible reasons for failure of treatment effects in the present study are discussed. Additional study will be required to determine whether there are neglect patients who may benefit from amantadine.

Specific features of sensorimotor cerebral cortex activity modulation by dopamine releaser amantadine

The modulatory effects of amantadine (1-adamantanamine) on the activity of sensorimotor cerebral cortex neurones during microiontophoretic application of agonists of glutamatergic and GABA-ergic (gamma-aminobutyric acid) transmission were studied. In non-anaesthetised cats, dopamine (DA) released by amantadine application in a small area of the neocortex increased baseline and evoked neuronal activity, providing stabilization and optimum course of both the neuronal and the conditioned responses of the animal. Amantadine eliminates a decrease in the level of neuronal baseline and evoked activity and marked increase in the latency of neuronal activation and conditioned movement mediated by D2 receptor antagonist sulpiride ((S)-5-aminosulfonyl-N-[(1-ethyl-2-pyrrolidinyl) methyl]-2-methoamantadineybenzamide) or GABA. This is reflected by a proportionate decrease in the onset of neuronal impulse reaction and latency of conditioned movement. Combined NMDA (N-methyl-D: -aspartate) and amantadine application also caused a considerable increase in baseline and evoked activity, but produced a slightly weaker effect than that evoked by NMDA application alone. A decrease in the baseline and evoked neuronal activity after NMDA withdrawn lasted during next control session (up to 40 min). The ability of DA releaser amantadine to alleviate significant increase in the latency of neuronal responses and conditioned movement induced by sulpiride or GABA suggests that dopamine modulates the activity of GABA-ergic inhibitory fast spike interneurons in the cat sensorimotor cortex during conditioning.

Functional neuroimaging applications for assessment and rehabilitation planning in patients with disorders of consciousness

OBJECTIVE

To describe the theoretic framework, design, and potential clinical applications of functional neuroimaging protocols in patients with disorders of consciousness.

DATA SOURCES

Recent published literature and authors' own work.

STUDY SELECTION

Studies using functional neuroimaging techniques to investigate cognitive processing in patients diagnosed with vegetative and minimally conscious state.

DATA EXTRACTION

Not applicable.

DATA SYNTHESIS

Positron-emission tomography activation studies suggest that the vegetative state represents a global disconnection syndrome in which higher order association cortices are functionally disconnected from primary cortical areas. In contrast, patterns of activation in functional magnetic resonance imaging studies of patients in the minimally conscious state show preservation of large-scale cortical networks associated with language and visual processing.

CONCLUSIONS

Novel applications of functional neuroimaging in patients with disorders of consciousness may aid in differential diagnosis, prognostic assessment and identification of pathophysiologic mechanisms. Improvements in patient characterization may, in turn, provide new opportunities for restoration of function through interventional neuromodulation.

Lateral impact in closed head injury: A substantially increased risk for diffuse axonal injury—A preliminary study

OBJECTIVE

Assessment, whether location of impact causing different facial fracture patterns was associated with diffuse axonal injury in patients with severe closed head injury.

METHODS

Retrospectively all patients referred to the Trauma Unit of the University Hospital of Zurich, Switzerland between 1996 and 2002 presenting with severe closed head injuries (Abbreviated Injury Scale (AIS) (face) of 2-4 and an AIS (head and neck) of 3-5) were assessed according to the Glasgow Coma Scale (GCS) and the Injury Severity Score (ISS). Facial fracture patterns were classified as resulting from frontal, oblique or lateral impact. All patients had undergone computed tomography. The association between impact location and diffuse axonal injury when correcting for the level of consciousness (using the Glasgow scale) and severity of injury (using the ISS) was calculated with a multivariate regression analysis.

RESULTS

Of 200 screened patients, 61 fulfilled the inclusion criteria for severe closed head injury. The medians (interquartile ranges 25;75) for GCS, AIS(face) AIS(head and neck) and ISS were 3 (3;13), 2 (2;4), 4 (4;5) and 30 (24;41), respectively. A total of 51% patients had frontal, 26% had an oblique and 23% had lateral trauma. A total of 21% patients developed diffuse axonal injury (DAI) when compared with frontal impact, the likelihood of diffuse axonal injury increased 11.0 fold (1.7-73.0) in patients with a lateral impact.

CONCLUSIONS

Clinicians should be aware of the substantial increase of diffuse axonal injury related to lateral impact in patients with severe closed head injuries.

Monoaminergic agonists for acute traumatic brain injury

BACKGROUND

Although there have been considerable gains in understanding the cascade of events that lead to secondary injury after traumatic brain injury (TBI), efforts to translate this understanding into new therapeutic, so-called neuroprotective approaches, have so far proven disappointing. As an alternative, there is growing interest in approaches to enhance brain repair after injury. Animal models suggest that agents enhancing monoaminergic (MA) transmission, particularly amphetamines, promote motor recovery from focal brain injury and it is proposed that this might represent a complementary means of therapeutic intervention in the later post-injury phase.

OBJECTIVES

To evaluate the evidence that MAs improve final outcome after TBI.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library, Issue 2, 2005), the Cochrane Injuries Group's Specialised Register (to May 2005), MEDLINE (1966 to May 2005), EMBASE (1980 to May 2005) and the Science Citation Index (1992 to June 2005). We contacted researchers and authors of published and unpublished trials. Searches were updated in May 2005.

SELECTION CRITERIA

Randomised controlled trials comparing the use of a MA (together with conventional non-pharmacological rehabilitative therapy) versus conventional non-pharmacological rehabilitative therapy alone.

DATA COLLECTION AND ANALYSIS

Two authors independently screened records, extracted data and assessed trial quality.

MAIN RESULTS

Although there is a limited clinical literature addressing this topic, none of the studies identified fully met inclusion criteria for this review.

AUTHORS' CONCLUSIONS

At present there is insufficient evidence to support the routine use of MAs to promote recovery after TBI.

Pharmacological management for agitation and aggression in people with acquired brain injury

BACKGROUND

Of the many psychiatric symptoms that may result from brain injury, agitation and/or aggression are often the most troublesome. It is therefore important to evaluate the efficacy of psychotropic medication used in its management.

OBJECTIVES

To evaluate the effects of drugs for agitation and/or aggression following acquired brain injury (ABI).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and other electronic databases. We also searched the reference lists of included studies and recent reviews. In addition we handsearched the journals Brain Injury and the Journal of Head Trauma Rehabilitation. There were no language restrictions. The searches were last updated in June 2006.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that evaluated the efficacy of drugs acting on the central nervous system for agitation and/or aggression, secondary to ABI, in participants over 10 years of age.

DATA COLLECTION AND ANALYSIS

We independently extracted data and assessed trial quality. Studies of patients within six months after brain injury and/or in a confusional state, were distinguished from those of patients more than six months post-injury, or who were not confused.

MAIN RESULTS

Six RCTs were identified and included in this review. Four of theses evaluated the beta-blockers, propranolol and pindolol, one evaluated the central nervous system stimulant, methylphenidate and one evaluated amantadine, a drug normally used in parkinsonism and related disorders. The best evidence of effectiveness in the management of agitation and/or aggression following ABI was for beta-blockers. Two RCTs found propranolol to be effective (one study early and one late after injury). However, these studies used relatively small numbers, have not been replicated, used large doses, and did not use a global outcome measure or long-term follow-up. Comparing early agitation to late aggression, there was no evidence for a differential drug response. Firm evidence that carbamazepine or valproate is effective in the management of agitation and/or aggression following ABI is lacking.

AUTHORS' CONCLUSIONS

Numerous drugs have been tried in the management of aggression in ABI but without firm evidence of their efficacy. It is therefore important to choose drugs with few side effects and to monitor their effect. Beta-blockers have the best evidence for efficacy and deserve more attention. The lack of evidence highlights the need for better evaluations of drugs for this important problem.

Dopamine agonist therapy in low-response children following traumatic brain injury

The objective of this study was to determine whether a dopamine agonist could improve mental status among children in a low-response state following traumatic brain injury. In an 8-week, prospective, double-blind, randomized trial, 10 children and adolescents ages 8 to 21 years (X = 16.7 years) with traumatic brain injury sustained at least 1 month previously and remaining in a low-response state (Rancho Los Amigos Scale level pound 3) received pramipexole or amantadine. Medication dosage was increased over 4 weeks, weaned over 2 weeks, and then discontinued. At baseline and weekly during the study, subjects were evaluated with the Coma Near Coma Scale, Western NeuroSensory Stimulation Profile, and Disability Rating Scale. Scores improved significantly from baseline to the medication phase on the Coma Near Coma Scale, Western NeuroSensory Stimulation Profile, and Disability Rating Scale (P < .005). The weekly rate of change was significantly better for all three measures on medication than off medication (P < .05). Rancho Los Amigos Scale levels improved significantly on medication as well (P < .05). There was no difference in efficacy between amantadine and pramipexole. No unexpected or significant side effects were observed with either drug. This clinical trial supports the benefit of two dopamine agonists in the restoration of functional arousal, awareness, and communication. These drugs can be helpful in accelerating eligibility for acute rehabilitation among children and adolescents who have sustained significant brain injuries.

Serum S-100B and cleaved-tau are poor predictors of long-term outcome after mild traumatic brain injury

PRIMARY OBJECTIVE

To determine the relationship of serum S-100B and C-tau levels to long-term outcome after mild traumatic brain injury (mild TBI).

RESEARCH DESIGN

A prospective study of 35 mild TBI subjects presenting to the emergency department.

METHODS AND PROCEDURES

Six hour serum S-100B and C-tau levels compared to 3-month Rivermead Post Concussion Questionnaire (RPCQ) scores and post-concussive syndrome (PCS).

MAIN OUTCOMES AND RESULTS

The linear correlation between marker levels and RPCQ scores was weak (S-100B: r = 0.071, C-tau: r = -0.21). There was no statistically significant correlation between marker levels and 3-month PCS (S-100B: AUC = 0.589, 95%CI. 038, 0.80; C-tau: AUC = 0.634, 95%CI 0.43, 0.84). The sensitivity of these markers ranged from 43.8-56.3% and the specificity from 35.7-71.4%.

CONCLUSIONS

Initial serum S-100B and C-tau levels appear to be poor predictors of 3-month outcome after mild TBI.

Neurorehabilitation issues in states of disordered consciousness following traumatic brain injury

The assessment and care of persons with disorders of consciousness (DOC) following catastrophic traumatic brain injury is often difficult and filled with both challenges and potential controversies. Rates of misdiagnosis of low-level neurological state (LLNS) patients with signs of awareness as being vegetative have been noted to be unacceptably high and call for better education and training regarding the assessment methodologies of individuals with DOC. Clinician knowledge regarding prognostication and neural recovery from LLNSs following traumatic brain injury is often lacking, as is awareness of the neurorehabilitative interventions that can potentially facilitate recovery, as well as minimize morbidity and mortality in this unique population of neurological patients.

Chronic disorders of consciousness

The vegetative state and the minimally conscious state are disorders of consciousness that can be acute and reversible or chronic and irreversible. Diffuse lesions of the thalami, cortical neurons, or the white-matter tracts that connect them cause the vegetative state, which is wakefulness without awareness. Functional imaging with PET and functional MRI shows activation of primary cortical areas with stimulation, but not of secondary areas or distributed neural networks that would indicate awareness. Vegetative state has a poor prognosis for recovery of awareness when present for more than a year in traumatic cases and for 3 months in non-traumatic cases. Patients in minimally conscious state are poorly responsive to stimuli, but show intermittent awareness behaviours. Indeed, findings of preliminary functional imaging studies suggest that some patients could have substantially intact awareness. The outcomes of minimally conscious state are variable. Stimulation treatments have been disappointing in vegetative state but occasionally improve minimally conscious state. Treatment decisions for patients in vegetative state or minimally conscious state should follow established ethical and legal principles and accepted practice guidelines of professional medical specialty societies.

Amantadine inhibits NMDA receptors by accelerating channel closure during channel block

The channel of NMDA receptors is blocked by a wide variety of drugs. NMDA receptor channel blockers include drugs of abuse that induce psychotic behavior, such as phencyclidine, and drugs with wide therapeutic utility, such as amantadine and memantine. We describe here the molecular mechanism of amantadine inhibition. In contrast to most other described channel-blocking molecules, amantadine causes the channel gate of NMDA receptors to close more quickly. Our results confirm that amantadine binding inhibits current flow through NMDA receptor channels but show that its main inhibitory action at pharmaceutically relevant concentrations results from stabilization of closed states of the channel. The surprising variation in the clinical utility of NMDA channel blockers may in part derive from their diverse effects on channel gating.

Amantadine to enhance readiness for rehabilitation following severe traumatic brain injury

PRIMARY OBJECTIVE

To evaluate the association between amantadine and recovery of consciousness from prolonged traumatic coma.

RESEARCH DESIGN

A retrospective cohort study.

METHODS

Subjects included 123 adults with severe traumatic brain injury (TBI) admitted over a 10-year period who remained in coma despite becoming medically stable.

EXPERIMENTAL INTERVENTIONS

Cases received 100-200 mg of amantadine twice daily.

MAIN OUTCOMES AND RESULTS

46.4% (13/28) of cases emerged from coma compared to 37.9% (36/95) of controls (p = 0.42). Somatosensory evoked potential (SSEP) was the only significant predictor of emergence from coma (p = 0.02), while SSEP, age and Glasgow Coma Score (GCS) significantly predicted time to emerge from coma (p < 0.05).

CONCLUSIONS

Although the study and its design do not support the view that amantadine has an effect on recovery of consciousness; it remains safe, inexpensive and has few side effects. The lack of treatment alternatives and anecdotal support for its use may warrant further study. Prospective controlled trials would yield more definitive results.

Amantadine for traumatic brain injury: does it improve cognition and reduce agitation?

OBJECTIVE

To review the available literature pertaining to amantadine as therapy for improving cognition and reducing agitation following a non-penetrating traumatic brain injury (TBI).

DATA SOURCES

Clinical literature was accessed through MEDLINE (from 1966 to February 2004) and bibliographic searches. Key search terms included 'amantadine', 'traumatic brain injury', 'cognition', and 'agitation'.

DATA SYNTHESIS

Amantadine is primarily used for treatment and prophylaxis of influenza A. Its ability to improve mentation and motor function in patients with head injury remains questionable. An evaluation of five clinical trials, two case reports, and one case series is conducted focusing on the use of amantadine following TBI. Patients in clinical trials were assessed using a variety of neuropsychological tools aimed at, among other things, assessing cognition and agitation. Although individual patient results varied, the majority of patients studied showed improved neuropsychological test scores. Similar observations are noted in the case reports and case series. Improvement in cognition and reduced agitation seems to occur with post-injury amantadine therapy.

CONCLUSIONS

Amantadine is a reasonable option for improving cognition and reducing agitation following a TBI but confirmatory evidence of the efficacy the drug is necessary.

Agitation After Traumatic Brain Injury

Posttraumatic agitation is a challenging problem for acute and rehabilitation staff, persons with traumatic brain injury, and their families. Specific variables for evaluation and care remain elusive. Clinical trials have not yielded a strong foundation for evidence-based practice in this arena. This review seeks to evaluate the present literature (with a focus on the decade 1995-2005) and employ previous clinical experience to deliver a review of the topic. We will discuss definitions, pathophysiology, evaluation techniques, and treatment regimens. A recommended approach to the evaluation and treatment of the person with posttraumatic agitation will be presented. The authors hope that this review will spur discussion and assist in facilitating clinical care paradigms and research programs.

Neurobehavioral Effects of Amantadine After Pediatric Traumatic Brain Injury

OBJECTIVE

To investigate the safety and efficacy of a dopamine agonist, amantadine hydrochloride (AMH), in the treatment of neurobehavioral sequelae of pediatric TBI.

PROCEDURES

Age- and severity-matched traumatic brain injury groups, randomized to AMH (n = 17) or usual care (n = 10), completed behavior scales and neuropsychological tests. Effect sizes measured the treatment effect within subjects and between groups. Side effects were tracked over the 12-week study course.

RESULTS

Behavior improved in the AMH group, but only those 2 years or fewer postinjury showed a treatment effect on cognitive tests.

CONCLUSIONS

After traumatic brain injury, a 12-week course of AMH was safe and, according to parent report, improved behavior. AMH may have the potential to improve cognition in more recently injured children.

Selegiline in the management of apathy following traumatic brain injury

PRIMARY OBJECTIVE

To provide a brief review of apathy following traumatic brain injury (TBI) and describe the use of selegiline in a group of patients with this symptom.

MAIN OUTCOME

Four patients are described who showed improvement in Apathy Evaluation Scale scores and functional improvement, following the use of selegiline. In each case, selegiline was well tolerated whereas methylphenidate was not.

CONCLUSIONS

Selegiline shows potential for the management of apathy following TBI. This provides further evidence that impaired dopaminergic processes are prominent in the genesis of these symptoms. However, these findings require confirmation in controlled studies.

Synaptosomal dopamine uptake in rat striatum following controlled cortical impact

Functional deficits following traumatic brain injury (TBI) are associated with alterations in markers of dopaminergic neurotransmission. To assess the effects of TBI on the expression and functional integrity of dopamine transporters, we measured transporter protein levels and investigated synaptosomal dopamine uptake in the rat striatum. Two or four weeks after lateral controlled cortical impact or sham injury, Western blotting revealed a decrease in transporter protein in the ipsilateral striatum of injured rats relative to shams (P < 0.05). However, no significant difference in synaptosomal uptake (K(m), V(max)) was found between injured and sham-injured animals. Our data suggest that striatal dopamine transporters are capable of normal function at 2 weeks and 4 weeks after injury. However, it is unclear whether neurons in the injured striatum can properly regulate the activity of dopamine transporters in vivo.

The vegetative and minimally conscious states: current knowledge and remaining questions

In the last 2 decades, the minimally conscious state has been distinguished conceptually from the vegetative state and operational criteria for these diagnoses have been published. Standardized and individualized assessment tools have been developed to assist with the diagnosis of severe disorders of consciousness and the measurement of clinical improvement. The natural course of recovery and the importance of key prognostic predictors have been elucidated. Important advances have also been made in defining the similarities and differences in the pathophysiology of these two states, and functional imaging modalities have begun to explicate the neural substrate underlying the behavioral features of these disorders. Research on the efficacy of treatments for severe disorders of consciousness lags behind, due to the practical and ethical difficulties in executing large rigorously controlled clinical trials. The past and future scientific developments in this area provide an important background for continuing discussions of the ethical controversies surrounding end-of-life decision making and resource allocation.

Neuropsychiatric consequences of traumatic brain injury: a review of recent findings

PURPOSE OF REVIEW

Behavioral and psychiatric disturbances are the more frequent consequences of traumatic brain injury and major determinants of the quality of life of patients. This review was designed to familiarize the reader with the more recent work published in this field.

RECENT FINDINGS

We have now a more consistent view of the epidemiology of post-traumatic brain injury psychiatric disorders both in adult and pediatric populations. Mood disorders, anxiety disorders and substance use disorders are the more prevalent psychiatric diagnoses among traumatic brain injury patients. The phenomenological characteristics and clinical correlates of major depression, post-traumatic stress disorder, alcohol use disorders, and post-traumatic brain injury attention deficit hyperactivity disorder have been studied in more detail. Newer structural, metabolic and functional neuroimaging techniques help to clarify the pathogenesis of these disorders. In turn, this knowledge may lead to the implementation of more efficient therapeutic interventions. Unfortunately, controlled treatment studies have been the exception in the field, and treatment decisions usually lack adequate empirical support.

SUMMARY

Recent advances in the basic neuroscience of traumatic brain injury as well as in behavioral genetics, social science and neuroimaging techniques should contribute to a better understanding of the pathophysiology of the psychiatric disorders occurring after the injury. There is a great need for randomized, double-blind, placebo-controlled trials to establish the most effective treatments for these disorders.

Amantadine for neurobehavioural deficits following delayed post-hypoxic encephalopathy

Delayed post-hypoxic encephalopathy is an uncommon but potentially debilitating consequence of hypoxic-ischemic brain injury. This condition is characterized by delayed neurological deterioration days-to-weeks after an initial partial or complete recovery from hypoxic-ischemic brain injury. The course of recovery from this condition is highly variable, ranging from rapid and fatal progression over several weeks to delayed but occasionally complete recovery. There are no reports describing neurorehabilitative, including neuropharmacologic, interventions for persons with persistent neurological and/or neurobehavioural deficits following delayed post-hypoxic encephalopathy. This study describes the case of a 24-year old male who developed delayed post-hypoxic encephalopathy following an unintentional methadone and diazepam overdose and who demonstrated cognitive and neurobehavioural improvements during treatment with amantadine HCl hydrochloride in a single-case, open-label design. A brief review of the literature regarding this condition, its treatment and suggestions for further study are presented.

Predictors of outcome in prolonged posttraumatic disorders of consciousness and assessment of medication effects: A multicenter study

OBJECTIVES

To develop predictive models of recovery from the vegetative state (VS) and minimally conscious state (MCS) after traumatic brain injury (TBI) and to gather preliminary evidence on the impact of various psychotropic medications on the recovery process to support future randomized controlled trials. Design Longitudinal observational cohort design, in which demographic information, injury and acute care history, neuroimaging data, and an initial Disability Rating Scale (DRS) score were collected at the time of study enrollment. Weekly follow-up data, consisting of DRS score, current psychoactive medications, and medical complications, were gathered until discharge from inpatient rehabilitation.

SETTING

Seven acute inpatient rehabilitation facilities in the United States and Europe with specialized programs for treating patients in the VS and MCS.

PARTICIPANTS

People with TBI (N=124) who were in the VS or MCS 4 to 16 weeks after injury.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

DRS score at 16 weeks after injury and time until commands were first followed (among those participants demonstrating no command following at study enrollment). Results DRS score at enrollment, time between injury and enrollment, and rate of DRS change during the first 2 weeks of poststudy observation were all highly predictive of both outcomes. No variables related to injury characteristics or lesions on neuroimaging were significant predictors. Of the psychoactive medications, amantadine hydrochloride was associated with greater recovery and dantrolene sodium was associated with less recovery, in terms of the DRS score at 16 weeks but not the time until commands were followed. More detailed analysis of the timing of functional improvement, with respect to the initiation of amantadine provided suggestive, but not definitive, evidence of the drug's causal role.

CONCLUSIONS

These findings show the feasibility of improving outcome prediction from the VS and MCS using readily available clinical variables and provide suggestive evidence for the effects of amantadine and dantrolene, but these results require confirmation through randomized controlled trials.

The minimally conscious state: defining the borders of consciousness

There is no agreement as to where the limits of consciousness lie, or even if these putative borders exist. Problems inherent to the study of consciousness continue to confound efforts to establish a universally accepted theory of consciousness. Consequently, clinical definitions of consciousness and unconsciousness are unavoidably arbitrary. Recently, a condition of severely altered consciousness has been described, which characterizes the borderzone between the vegetative state and so-called "normal" consciousness. This condition, referred to as the minimally conscious state (MCS), is distinguished from the vegetative state by the presence of minimal but clearly discernible behavioral evidence of self or environmental awareness. This chapter reviews the diagnostic criteria, pathophysiology, prognostic relevance, neurobehavioral assessment procedures and treatment implications associated with MCS.

Twenty Years of Pharmacology

During the past 20 years in pharmacology, a number of innovations have appeared that have resulted in significant changes in the drugs available for people with traumatic brain injury. Among the anticonvulsants, antidepressants, and antipsychotics, new drugs have appeared with fewer cognitive side effects. In these classes of drugs, as well as among central nervous system stimulants, once-daily or other sustained-release preparations have been introduced that make it considerably more likely that the patient will take his or her medication, with smaller fluctuations in drug levels as well. New drugs have also resulted in a greater number of medications for the clinician to choose from. The overall effect has been a dramatic change in pharmacology that has benefited people with traumatic brain injury.

Amantadine in Pediatric Patients with Traumatic Brain Injury

OBJECTIVE

To determine if amantadine use in pediatric patients with traumatic brain injury is well tolerated and to attempt to assess its effectiveness.

DESIGN

This was a retrospective, case-controlled study.

RESULTS

Of the 54 patients, aged 3-18 yrs, who were administered amantadine, five (9%) had side effects that might have been related to the drug. These included hallucinations, delusions, increased aggression, and nausea/vomiting. The side effects were reversed when the medication was stopped or the dosage decreased. Patients in the amantadine group had a greater increase in Ranchos Los Amigos level during their admission than those in the control group (median, 3 vs. 2; P < 0.01). This difference may be, at least in part, explained by the fact that the amantadine group started at a lower Ranchos Los Amigos level (median, 3 vs. 4; P < 0.01). There were subjective improvements noted in 29 of the 46 patients (63%) in the amantadine group whose full charts were available for review.

CONCLUSION

Amantadine is a well tolerated medication when it is used in pediatric patients with traumatic brain injury. Subjective improvements were noted in the majority of the patients administered amantadine, and the amantadine group showed a greater improvement in Ranchos Los Amigos level during admission, suggesting that it may be effective.

Rehabilitative management of patients with disorders of consciousness: grand rounds

BACKGROUND

There are no standards of care to guide the selection of rehabilitation assessment and treatment procedures for patients with disorders of consciousness. Recently, consensus-based recommendations for management of patients in the vegetative and minimally conscious states have been developed and disseminated in neurology and neurorehabilitation. This is an important first step toward achieving evidence-based guidelines of care.

OBJECTIVE

Using a "Grand Rounds" format, we illustrate the application of consensus-based diagnostic, prognostic, and treatment recommendations in a patient who sustained severe traumatic brain injury with prolonged alteration in consciousness. After discussing the salient features of the case, we summarize the basic tenets of clinical care for this population.

Positive behavioural disturbances in the rehabilitation phase after severe traumatic brain injury: an historic cohort study

PRIMARY OBJECTIVE

To investigate the association of post-traumatic amnesia (PTA) with positive behavioural disturbances (PBD) in an historic cohort of patients with severe traumatic brain injury (TBI) and to evaluate the use and effects of neuroleptic drugs in this cohort.

RESEARCH DESIGN

Historic cohort study.

METHODS

The medical files of 60 patients with severe TBI, selected for inpatient rehabilitation during a period of 5.5 years, were independently examined for the presence of PTA and PBD at admission in the rehabilitation centre as well as for the concomitant use of neuroleptic drugs. All TBI patients with PBD at admission were subjected to special nursing measures consisting of a structured and safe environment, a minimum number of caregivers and provision of simple and consistent feedback. As a basic policy, the use of neuroleptic medication was minimized or stopped.

RESULTS

Of the 28 patients suffering from PTA at admission, 16 demonstrated PBD (positive predictive value 0.57 (95% CI 0.45-0.70)). In contrast, all the 32 patients without PTA but one did not show PBD (negative predictive value 0.97 (95% CI 0.93-1.00)). Seven of the 17 patients with PBD (41%) had been prescribed neuroleptic medication, of whom five patients (81%) experienced undesired side effects. Because of the special nursing measures, these drugs could be stopped or substituted by non-neuroleptic behaviour-modifying drugs in all patients within 3 weeks, without aggravation of their PBD.

CONCLUSIONS

These results suggest that impaired attention and memory may play a critical role in the development of PBD in patients with severe TBI. From this perspective, maximum effort must be made to improve TBI patients' level of attention, memory and orientation instead of using mechanical or chemical restraints.

Traumatic brain injury

PURPOSE OF REVIEW

Management of the patient with traumatic brain injury is a rapidly advancing field, characterized in recent years by an improved understanding of intracranial pathophysiology and ways in which outcomes can be improved. Many traditional therapies, such as fluid restriction and hyperventilation, have been called into question and are no longer recommended. Other proposed therapies, such as deliberate hypothermia, remain controversial. This detailed review of the recent literature helps the reader come to an understanding of current scientific and evidence-based practices in this area, with emphasis on those therapies most likely to be of use to the practicing intensivist.

RECENT FINDINGS

High-quality care of the traumatic brain injury patient demands the integrated activities of a number of different medical and nursing specialties. The best outcomes today are achieved by those systems that are able to focus as a team on the collective goal of minimizing secondary brain injury, and the respiratory therapist adjusting the patient's mechanical ventilation may be just as important to this effort as the attending neurosurgeon. Although the search for new diagnostic, prognostic, and therapeutic modalities continues (many of the more promising of which are reviewed in this article), it is clear that there exists no "silver bullet" therapy that will help all patients. Instead, it is the systematic integration and application of many small advances that will ultimately lead to better outcomes.

SUMMARY

Some issues in traumatic brain injury have now been resolved, and specific recommendations can be made. Fluid therapy directed toward a euvolemic state is now universally recommended, for example, as is the role of intracranial pressure monitoring. Other areas, such as the use of hypertonic saline, remain controversial. In both cases the authors have made an effort to cite the most recent literature, so that readers can draw their own conclusions from the original source material.

Mood disorders following traumatic brain injury

Mood disorders are a frequent complication of traumatic brain injury that exerts a deleterious effect on the recovery process and psychosocial outcome of brain injured patients. Prior psychiatric history and impaired social support have been consistently reported as risk factors for developing mood disorders after traumatic brain injury (TBI). In addition, biological factors such as the involvement of the prefrontal cortex and probably other limbic and paralimbic structures may play a significant role in the complex pathophysiology of these disorders. Preliminary studies have suggested that selective serotonin reuptake inhibitors such as sertraline, mood stabilizers such as sodium valproate, as well as stimulants and ECT may be useful in treating these disorders. Mood disorders occurring after TBI are clearly an area of neuropsychiatry in which further research in etiology as well as treatment is needed.

Noradrenergic agonists for acute traumatic brain injury

BACKGROUND

Although there have been considerable gains in understanding the cascade of events that lead to secondary injury after traumatic brain injury (TBI), efforts to translate this understanding into new therapeutic, so-called neuroprotective, approaches have so far proven disappointing. Animal models suggest an alternative strategy: agents enhancing monoaminergic transmission, particularly amphetamines, have been shown to promote motor recovery from focal brain injury and it has been suggested that this might represent a complementary means of therapeutic intervention in the later post-injury phase.

OBJECTIVES

To evaluate the evidence that amphetamines improve final outcome after traumatic brain injury.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, Science Citation Index, Cochrane Controlled Trials Register and the Cochrane Injuries Group's Specialised Register of Controlled Trials. Researchers and authors of published trials were also contacted.

SELECTION CRITERIA

Randomised controlled trials comparing the use of a noradrenergic agonist (together with conventional non-pharmacological rehabilitative therapy) versus conventional non-pharmacological rehabilitative therapy alone.

DATA COLLECTION AND ANALYSIS

Two reviewers independently screened records, extracted data and assessed trial quality.

MAIN RESULTS

Although there is a limited clinical literature addressing this topic, none of the studies identified fully meets inclusion criteria for this review.

REVIEWER'S CONCLUSIONS

At present there is insufficient evidence to support the routine use of methylphenidate or other amphetamines to promote recovery from TBI.

Traumatic brain injury reduces dopamine transporter protein expression in the rat frontal cortex

Disturbances in dopamine neurotransmission contribute to frontal lobe dysfunction after traumatic brain injury. The changes in dopamine neurotransmission may be mediated by alterations in the dopamine transporter, which plays a key role in maintaining dopamine homeostasis. To determine whether the dopamine transporter system is altered after traumatic brain injury, dopamine transporter protein was examined bilaterally in the rat frontal cortex by Western blot at 1, 7, and 28 days after controlled cortical impact or sham injury ( = 6/group). Dopamine transporter protein expression was decreased in the injured (ipsilateral) cortex at 7 days and bilaterally at 28 days in injured sham control rats. The decrease in dopamine transporter protein levels may reflect a traumatic brain-injury-induced down-regulation of dopamine transporter and/or a loss of dopaminergic fibers.