The effect of bromocriptine on speech dysfunction in patients with diffuse brain injury (akinetic mutism)

Amphetamine and methylphenidate potential on the recovery from stroke and traumatic brain injury: a review

The prevalence of stroke and traumatic brain injury is increasing worldwide. However, current treatments do not fully cure or stop their progression, acting mostly on symptoms. Amphetamine and methylphenidate are stimulants already approved for attention deficit hyperactivity disorder and narcolepsy treatment, with neuroprotective potential and benefits when used in appropriate doses. This review aimed to summarize pre-clinical and clinical trials testing either amphetamine or methylphenidate for the treatment of stroke and traumatic brain injury. We used PubMed as a database and included the following keywords ((methylphenidate) OR (Ritalin) OR (Concerta) OR (Biphentin) OR (amphetamine) OR (Adderall)) AND ((stroke) OR (brain injury) OR (neuroplasticity)). Overall, studies provided inconsistent results regarding cognitive and motor function. Neurite outgrowth, synaptic proteins, dendritic complexity, and synaptic plasticity increases were reported in pre-clinical studies along with function improvement. Clinical trials have demonstrated that, depending on the brain region, there is an increase in motor activity, attention, and memory due to the stimulation of the functionally depressed catecholamine system and the activation of neuronal remodeling proteins. Nevertheless, more clinical trials and pre-clinical studies are needed to understand the drugs' full potential for their use in these brain diseases namely, to ascertain the treatment time window, ideal dosage, long-term effects, and mechanisms, while avoiding their addictive potential.

On the pathophysiology and treatment of akinetic mutism

Akinetic mutism (AM) is a rare neurological disorder characterized by the presence of an intact level of consciousness and sensorimotor capacity, but with a simultaneous decrease in goal-directed behavior and emotions. Patients are in a wakeful state of profound apathy, seemingly indifferent to pain, thirst, or hunger. It represents the far end within the spectrum of disorders of diminished motivation. In recent years, more has become known about the functional roles of neurocircuits and neurotransmitters associated with human motivational behavior. More specific, there is an increasing body of behavioral evidence that links specific damage of functional frontal-subcortical organization to the occurrence of distinct neurological deficits. In this review, we combine evidence from lesion studies and neurophysiological evidence in animals, imaging studies in humans, and clinical investigations in patients with AM to form an integrative theory of its pathophysiology. Moreover, the specific pharmacological interventions that have been used to treat AM and their rationales are reviewed, providing a comprehensive overview for use in clinical practice.

Review of Awakening Agents

Brain injuries are a serious burden of illness to Canada and the US. Advances in managing head trauma have allowed more patients to emerge from decreased levels of consciousness and helped them cope with neurocognitive, neurobehavioural, and neuropsychiatric deficits. In this article, we review the current (1986-2002) evidence surrounding the pharmacological management of arousal states and the aforementioned neurological sequelae of head injury in either acute or chronic conditions. This article will review the evidence for the use of psychostimulants (methylphenidate), antidepressants (amitriptyline, selective serotonin reuptake inhibitors, and buproprion), Parkinson’s medications (amantadine, bromocriptine, carbidopa/levodopa), anticonvulsants (valproic acid), modafinil (Provigil), lactate, hyperbaric oxygen chamber, electroconvulsive therapy, and transmagnetic stimulation, in patients following a head injury. The review did not include all anticonvulsants, neuroleptics, beta-blockers, benzodiazepines, azospirones or cognitive enhancers. Unfortunately, the quality of the evidence is generally poor, and sometimes conflicting, which in turn results in indecisive guidelines for treating patients. Accepting the inherent flaws in the evidence we feel that this paper may serve as a stepping-stone for future researchers to improve data gathering that targets neurocognitive, neurobehavioural and neuropsychiatric symptoms following a head injury.

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

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

Advances in neuropharmacological rehabilitation for brain dysfunction

The use of pharmacological agents as rehabilitative tools following brain injury remains to some degree both a science and an art. Recent work in the area of the neural sciences has shed new light on the workings of basic CNS neurochemical systems and the use of pharmacologic agents in altering central neurophysiologic processes. The major central neurochemical systems are reviewed both anatomically and physiologically. An overview is provided of basic neuropharmacologic agents by class. Lastly, some of the newer neuropharmacological options for treatment of post-acute brain injury deficits are examined.

Mechanisms of working memory dysfunction after mild and moderate TBI: evidence from functional MRI and neurogenetics

Cognitive complaints are a frequent source of distress and disability after mild and moderate traumatic brain injury (TBI). While there are deficits in several cognitive domains, many aspects of these complaints and deficits suggest that problems in working memory (WM) play an important role. Functional imaging studies in healthy individuals have outlined the neural substrate of WM and have shown that regions important in WM circuitry overlap with regions commonly vulnerable to damage in TBI. Use of functional MRI (fMRI) in individuals with mild and moderate TBI suggests that they can have problems in the activation and allocation of WM, and several lines of evidence suggest that subtle alterations in central catecholaminergic sensitivity may underlie these problems. We review the evidence from fMRI and neurogenetic studies that support the role of catecholaminergic dysregulation in the etiology of WM complaints and deficits after mild and moderate TBI.

Bromocriptine in traumatic brain injury

The authors report the case of a 63-year-old patient with severe traumatic brain injury (TBI) associated with Parkinson's syndrome, whose performances were dramatically improved by bromocriptine therapy, with an improvement of the scores, not only on tests evaluating motor functions but also on tests evaluating the patient's cognitive functions. However, no improvement was observed with levodopa.

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.

Bromocriptine reduces lipid peroxidation and enhances spatial learning and hippocampal neuron survival in a rodent model of focal brain trauma

Oxidative stress is a significant contributor to the secondary sequelae of traumatic brain injury (TBI), and may mediate subsequent neurobehavioral deficits and histopathology. The present study examined the neuroprotective effects of bromocriptine (BRO), a dopamine D2 receptor agonist with significant antioxidant properties, on cognition, histopathology, and lipid peroxidation in a rodent model of focal brain trauma. BRO (5 mg/kg) or a comparable volume of vehicle (VEH) was administered intraperitoneally 15 min prior to cortical impact or sham injury. In experiment 1, spatial learning was assessed in an established water maze task on post-surgery days 14-18, followed by quantification of hippocampal cell survival and cortical lesion volume at 4 weeks. In experiment 2, rats were sacrificed 1 hr post-surgery, and malondialdehyde (MDA), the end product of lipid peroxidation, was measured in the frontal cortex, striatum, and substantia nigra using a thiobarbituric acid reactive substances assay. The TBI+BRO group was significantly more adept at locating a hidden platform in the water maze compared to the TBI+VEH group and also exhibited a greater percentage of surviving CA3 hippocampal neurons. TBI increased MDA in all examined regions of the VEH-treated, but not BRO-treated group versus SHAMs. MDA was significantly decreased in both the striatum (4.22 +/- 0.52 versus 5.60 +/- 0.44 nmol per mg/tissue +/- SEM) and substantia nigra (4.18 +/- 0.35 versus 7.76 +/- 2.05) of the TBI+BRO versus TBI+VEH groups, respectively, while only a trend toward decreased MDA was observed in the frontal cortex (5.44 +/- 0.44 versus 6.96 +/- 0.77). These findings suggest that TBI-induced oxidative stress is attenuated by acute BRO treatment, which may, in part, explain the benefit in cognitive and histological outcome.

Working memory deficits after traumatic brain injury: catecholaminergic mechanisms and prospects for treatment -- a review

PRIMARY OBJECTIVE

To review the neural circuitry and neurochemistry of working memory and outline the evidence for working memory deficits after traumatic brain injury, and the evidence for the use of catecholaminergic agents in the amelioration of these deficits. Current knowledge gaps and research needs are identified.

MAIN OUTCOMES AND RESULTS

Impairments in working memory are a core component of the cognitive deficits associated with traumatic brain injury. Recent progress in understanding the neural circuitry and neurochemistry of working memory suggests that catecholamines play a central role in the activation and regulation of working memory and thus lays a framework in which to consider the use of catecholaminergic agents (dopaminergic and alpha-2 adrenergic agonists) in the treatment of specific cognitive deficits after traumatic brain injury.

CONCLUSIONS

The combined methods of cognitive neuroscience, functional brain imaging and neuropharmacology are proposed as an excellent method for studying working memory deficits. A strong rationale exists for the targeted use of catecholaminergic agonists in the treatment of working memory deficits after traumatic brain injury.

Bromocriptine-responsive akinetic mutism following endoscopy for ventricular neurocysticercosis. Case report and review of the literature

A 26-year-old woman with obstructive hydrocephalus caused by a cysticercal cyst blocking the left foramen of Monro was initially treated with an external ventriculostomy and subsequent endoscopically assisted cyst resection and septostomy. Postoperatively, the patient developed the clinical syndrome of akinetic mutism, but her condition improved after the administration of the dopaminergic agonist bromocriptine. This result indicates that a disruption in the ascending dopaminergic pathway involved in behavior formation was likely the cause of these neurological symptoms.

Bradykinesia and bradyphrenia revisited: patterns of subclinical deficit in motor speed and cognitive functioning in head-injured patients with good recovery

Twenty-four patients, showing a good clinical recovery from coma-inducing injury and coping well with the activities of everyday living, were tested, at least 1 year after trauma, on motor speed and reaction time, and given a neuropsychological examination. While the patients generally performed within the normal range on the neuropsychological tests, their motor speeds and reaction times--both simple (SRT) and complex (CRT)--were significantly slower than those of matched controls. This points to a subclinical bradykinesia. The patients' motor speed scores did not correlate significantly with any of the neuropsychological tests; nor did SRT or CRT. While the difference between simple and complex reaction time was significantly greater in the patient group, the percentage difference was not significantly different between the two groups. Collectively, these results suggest that bradykinesia and bradyphrenia do not necessarily overlap. Finally, there was no significant correlation between motor performance and severity of original injury, whether the latter was measured by number and size of lesions or by duration of post-traumatic amnesia.

The agitated brain injured patient. Part 2: Pathophysiology and treatment

The management of agitation after brain injury remains uncertain because of a lack of a consistent definition and a poor understanding of the underlying mechanism. Part 1 of this review focused on definitions, differential diagnosis, and assessment. Part 2 reviews potential mechanisms for posttraumatic agitation and common intervention strategies. The intent of this two-part series is to advocate for a consistent definition for posttraumatic agitation, to encourage the use of appropriate assessment and monitoring strategies, and to recommend that intervention decisions are based on at least a theoretical understanding of the relationship between specific target behaviors and probable brain-behavior relationships.

The use of methylphenidate in paediatric traumatic brain injury

Methylphenidate (MPH) has been used safely and effectively for many years in children for the treatment of attention deficit disorder with hyperactivity (ADHD). Behavioural and cognitive sequelae to traumatic brain injury (TBI) have features in common with ADHD, and MPH has been reported to be an effective treatment in adults with TBI. There is little literature documenting the efficacy of MPH in children with TBI. A chart review of 10 children who had sustained TBI and were subsequently treated with MPH was performed. Nine of the cases resulted from motor-vehicle accidents, and one from a fall. The severity of TBI ranged from mild to severe. In eight of the cases, MPH was used for cognitive and behavioural problems, and in two cases it was used to stimulate minimally responsive patients. The introduction of MPH improved cognitive function, behaviour and arousal as measured by parental and teacher reports, evaluation by in-/outpatient rehabilitation team, and/or neuropsychometric testing. MPH appears to be an effective treatment for post-TBI cognitive and behavioural sequelae in children, as well as improving arousal in the minimally responsive brain-injured child. Further prospective research is necessary to clarify the role of MPH in children with TBI.

Improved arousal and initiation following tricyclic antidepressant use in severe brain injury

Three patients with severe traumatic brain injury demonstrated significant improvement in arousal and initiation after administration of tricyclic antidepressants. The first patient showed improved motor and speech initiation in response to amitriptyline following several months of functional plateau. The second patient was minimally responsive 2 months after injury and demonstrated improved arousal following the use of desipramine. Both patients deteriorated when the medications were discontinued and improved again when they were restarted. These two cases provide strong evidence for a medication effect. The third patient began to verbalize following desipramine administration, despite being mute for more than a year after injury. Previous case reports describe cognitive-enhancing effects, such as improved arousal, attention, memory, and initiation, of dopaminergic agents, and in the case of tricyclic antidepressants, effects on agitation. The role of norepinephrine in promoting neurological recovery after brain lesions has been demonstrated in animals. The cases presented here provide some of the first data to show similar efficacy in humans and underscore the need for controlled trials to better determine which patients will benefit.

The therapeutic potential of bromocriptine in neuropsychological rehabilitation of patients with acquired brain damage

1. Activation of neuropsychological rehabilitation by pharmacological agents is a promising therapeutic strategy. 2. Reports of single cases and case series claim improvement of akinetic mutism, non-fluent aphasia, apathy, attentional and other neuropsychiatric disturbances after treatment with bromocriptine, a D2 dopamine receptor agonist. 3. A critical review of published reports and own experiences discusses the results in the light of pharmacological and neurobiological considerations. 4. Dopaminergic stimulation after certain kinds of brain damage might influence neuronal recovery and/or substitute dopaminergical linked functions after destruction of the corresponding neurons. 5. Although controlled clinical studies are very difficult to design and such evidence is still lacking, preliminary recommendations are given with regard to differential indications, drug regime and evaluation criteria.

Protriptyline as an alternative stimulant medication in patients with brain injury: a series of case reports

The results of a series of eight individual case reports in which protriptyline, an activating tricyclic antidepressant, was used as a 'stimulant' medication are presented. For some patients with head injury, traditional stimulants, such as methylphenidate, or dopaminergic stimulants, such as levodopa-carbidopa, amantadine, or bromocriptine, may be partially or totally ineffective or not tolerated. Protriptyline can be a very effective alternative and, for some patients, may be the most effective stimulant tried. In low to moderate doses, protriptyline should be considered for trials as an activating/stimulant medication in patients with head injury.

Treating organic abulia with bromocriptine and lisuride: four case studies

Abulia refers to an impairment of will, or the inability to initiate behaviour and action. There are reports of successful treatment of akinetic mutism, the most severe form of abulia, with bromocriptine. Four case studies are presented describing the successful treatment of abulia at a lesser severity than akinetic mutism with bromocriptine. Abulia was caused by brain damage due to alcohol in two cases, Wilson's disease and basal ganglia infarct in one each. Maximum bromocriptine dose varied from 25-70 mg. All improved considerably. Withdrawal or reduction of medication in three produced deterioration. The prescription of a neuroleptic drug had a similar effect in the fourth. One patient with a previous history developed a depressive relapse and so the drug was withdrawn and lisuride introduced. This produced a similar improvement. These cases highlight the value of identifying the syndrome of organic abulia and suggest that dopamine agonists may have a place in its treatment, though controlled studies are needed.