Effects of methylphenidate on attentional function after traumatic brain injury. A randomized, placebo-controlled trial

Traumatic brain injury in older adults

Traumatic brain injury (TBI) is a serious health risk for older adults, and the consequences of TBI range from full recovery to death. For many who survive, there is a legacy of cognitive, physical, and emotional disability. Falls are the major cause of head injury in older adults. There are many risk factors including pre-existing brain disease, other diseases, and, sometimes, iatrogenic factors. Efforts directed at prevention are of great importance. Outcome studies indicate that outcome is generally worse for older people than for younger people with similar injuries, but older individuals also deserve aggressive rehabilitation directed at the best possible recovery. This review will discuss the symptoms and syndromes that commonly result from TBI with comments about treatment.

A differential diagnostic approach to the pharmacological treatment of cognitive, behavioral, and affective disorders after traumatic brain injury

The choice of pharmacologic treatment for cognitive, behavioral, or affective disorders following TBI depends upon an accurate diagnosis of the underlying disorder responsible for the clinical picture presented. However there are a myriad of possible causes for each sign or symptom, and often several contributing factors. A differential diagnostic approach is presented that structures the search for etiology into several categories: preinjury diagnosis, neuropsychological disorders, sensorimotor disorder, medical disorders, adverse effects of medications, reactive mood and anxiety disorders, and sleep disorders.

Psychostimulant use in the rehabilitation of individuals with traumatic brain injury

BACKGROUND

Psychostimulants are used commonly in the rehabilitation of individuals with traumatic brain injury (TBI), despite the dearth of well-controlled studies of their effects. The available literature suggests that these drugs predominantly affect the speed of cognitive processing and certain observational ratings of mood and behavior. Effects on sustained attention, distractibility, and memory are less clear.

OBJECTIVE

This article reviews the controlled research literature on the use of these drugs in TBI and presents preliminary data from the authors' laboratory that extends these findings. Some of the common research pitfalls that have limited progress in research on these drugs are discussed.

Methylphenidate treatment

Methylphenidate is the psychotropic drug most commonly used to treat individuals suffering from developmental attention-deficit-hyperactivity disorder. Additional attention deficit is part of numerous neurologic diseases in childhood. Despite the vast extent of scientific research on methylphenidate, the use of this stimulant in the treatment of cognitive and behavioral dysfunction in children with epilepsy, brain tumor, leukemia, closed brain injury, encephalitis, meningitis, or mental retardation continues to be controversial. Only few data exist about the efficacy and side effects of methylphenidate treatment in children with this neurologic illness or history. The aim of the present study is to provide a review of this important clinical topic and perhaps to stimulate further controlled investigations.

Treatments of unilateral neglect: a review

OBJECTIVES

To review the existing literature on treatments of unilateral neglect, to synthesize findings, and to offer recommendations for future studies.

DATA SOURCES

Computerized databases including MEDLINE and PsychINFO.

STUDY SELECTION

All studies investigating treatment(s) of unilateral neglect.

DATA EXTRACTION

Authors reviewed design and other methodologic issues.

DATA SYNTHESIS

Unilateral neglect is a common consequence of right-hemisphere stroke. It is well recognized that the disorder is heterogeneous and has numerous subtypes. There have been numerous studies showing that arousal, hemispheric activation, and spatial attention treatments may all improve neglect, at least transiently. Despite these promising outcomes, little consensus exists as to whether 1 treatment is more efficacious than others, in part because cross-study differences in methodology render meta-analyses difficult, and in part because many studies fail to document duration of treatment effects or generalization to daily activities. One possibility is that these varied and diverse treatments may all be effective, reflecting redundancy in neural circuits devoted to attention and action in space, and consequent flexibility of the spatial processing system. It remains possible, however, that different subtypes of neglect may respond differentially to treatment of various sorts. Most existing studies of neglect have relied on very small populations of neglect patients, whose neglect is characterized only generally.

CONCLUSION

Methodologic shortcomings hinder assessment of the efficacy of various types of neglect treatment. In the future, these shortcomings could be addressed with larger studies of well-characterized patients that evaluate duration of treatment effects and include functional measures. In addition, the role of overarching variables, such as reduced arousal, requires consideration. The ultimate goal of these studies might be the development of triaging strategies wherein neglect patients are assigned to treatments of most likely benefit on the basis of neuroanatomic and behavioral profiles.

Cognitive Impairment Following Traumatic Brain Injury

Cognitive impairments due to traumatic brain injury (TBI) are substantial sources of morbidity for affected individuals, their family members, and society. Disturbances of attention, memory, and executive functioning are the most common neurocognitive consequences of TBI at all levels of severity. Disturbances of attention and memory are particularly problematic, as disruption of these relatively basic cognitive functions may cause or exacerbate additional disturbances in executive function, communication, and other relatively more complex cognitive functions. Because of the high rate of other physical, neurologic, and psychiatric syndromes following TBI, a thorough neuropsychiatric assessment of the patient is a prerequisite to the prescription of any treatment for impaired cognition. Psychostimulants and other dopaminergically active agents (eg, methylphenidate, dextroamphetamine, amantadine, levodopa/carbidopa, bromocriptine) may modestly improve arousal and speed of information processing, reduce distractibility, and improve some aspects of executive function. Cautious dosing (start-low and go-slow), frequent standardized assessment of effects and side effects, and monitoring for drug-drug interactions are recommended. Cognitive rehabilitation is useful for the treatment of memory impairments following TBI. Cognitive rehabilitation may also be useful for the treatment of impaired attention, interpersonal communication skills, and executive function following TBI. This form of treatment is most useful for patients with mild to moderate cognitive impairments, and may be particularly useful for those who are still relatively functionally independent and motivated to engage in and rehearse these strategies. Psychotherapy (eg, supportive, individual, cognitive-behavioral, group, and family) is an important component of treatment. For patients with medication- and rehabilitation-refractory cognitive impairments, psychotherapy may be needed to assist both patients and families with adjustment to permanent disability.

Stimulant drugs

Stimulants are a key element in the treatment of ADHD. Carefully designed trials of stimulants have found substantial improvement in ADHD core behaviours in 65-75 % of subjects with ADHD. Most standard stimulants are rapidly absorbed, with their behavioural effects appearing within 30 minutes, reaching a peak within one to three hours and disappearing within five hours. Doses at school are often necessary, in spite of the risk of peer ridicule and added adult supervision requirements. The mechanism by which stimulants act to reduce hyperactivity is not completely understood, but they improve impulsivity and activity levels. Several controlled evaluations made over periods of time greater than a year show a clear persistence of medication effects over time. A carefully crafted programme of treatment with methylphenidate is more effective in the reduction of hyperactivity symptoms than an intensive programme of behavioural and cognitive intervention. The combination of stimulants with psychosocial interventions in ADHD offers few advantages over medication alone. Unchallengeable guides to practice that would be appropriate everywhere are difficult to propose. It is imperative that clinicians prescribing stimulants should monitor the use of the drug properly, making sure that it is not being abused by the child's family, peers or those dispensing medication at school. Polypharmacy should only be embarked on by a specialist service and the combination of methylphenidate and clonidine should be used cautiously. Apart from ADHD, stimulants are useful in narcolepsy, resistant depression and partial syndromes of attention and hyperactivity. Major gaps in knowledge remain; pharmacokinetics, pharmacodynamics and pharmacogenetics of stimulant effects need further study. Details of stimulant administration regimes seem to have a major effect on the response achieved. Further research is needed, preferably in realistic practice settings, comparing different forms of combination with psychological interventions, investigating the effects in groups of children outside the core of schoolaged children with typical ADHD: preschool children, adults, those with partial syndromes (such as inattentiveness) and those with co-morbid disorders.

Positive outcomes in traumatic brain injury-vegetative state: patients treated with bromocriptine

OBJECTIVE

To assess the effects of multidisciplinary rehabilitation interventions and use of bromocriptine on outcome in patients with traumatic brain injury-vegetative state (TBI-VS).

DESIGN

Retrospective review of clinical cases.

SETTING

Free-standing rehabilitation hospital; Acute and extended rehabilitation hospital.

PARTICIPANTS

Five consecutive TBI-VS patients, as well as 33 TBI-VS patients and 37 traumatic brain injury-minimally conscious state (TBI-MCS) patients reported in the literature.

INTERVENTIONS

Bromocriptine administration, systematic neuropsychologic testing, sensory stimulation, and traditional comprehensive rehabilitation with physical therapy, occupational therapy, and speech therapy.

MAIN OUTCOME MEASURES

Disability Rating Scale (DRS) at 1, 3, 6, and 12 months postinjury and FIM instrument scores at 1 month and 12 months postinjury, Coma Recovery Scale, and Barry Rehabilitation Inpatient Screening of Cognition.

RESULTS

The 5 TBI-VS patients emerged from a VS into a MCS and regained functional status. Their recovery of physical and cognitive functioning, as rated by the DRS, was greater than previously reported in the literature for patients in a VS or MCS at 3, 6, and 12 months postinjury.

CONCLUSION

Bromocriptine administration, systematic neuropsychologic testing, sensory stimulation, a comprehensive rehabilitation program, or a combination of these treatments may enhance functional recovery in this TBI-VS patient group. Further systematic study to quantify the contribution of these variables and to reproduce this data in a larger patient population should be performed.

Methylphenidate: its pharmacology and uses

Methylphenidate is a commonly used medication in the United States. This central nervous system stimulant has a mechanism of action distinct from that of amphetamine. The Food and Drug Administration has approved methylphenidate for the treatment of attention-deficit/hyperactivity disorder and narcolepsy. Treatment with methylphenidate has been advocated in patients with traumatic brain injury and stroke, cancer patients, and those with human immunodeficiency virus infection. Placebo-controlled trials have documented its efficacy as an adjunctive agent in the treatment of depression and pain. This article reviews the current understanding of the mechanism of action and efficacy of methylphenidate in various clinical conditions.

The hippocampus: anatomy, pathophysiology, and regenerative capacity

Cognitive deficits following insults to the central nervous system-particularly those involving the hippocampus and related structures-are often persistent and severely debilitating. Progress has been made in establishing the role of the hippocampus in integrating information in the formation of memory necessary for subsequent recollection of information. The present article will review anatomic, physiological, and functional aspects of the hippocampus in reference to learning and memory. Both animal and human hippocampal pathophysiological processes will be explored. Adaptive and maladaptive central nervous system responses will be reviewed, with a special emphasis on neurogenesis. Ideally, physiological and cellular compensatory responses ought to parallel clinical observation. However, this association is not clearly established. Finally, the current understanding of neuromodulatory mechanisms (although quite preliminary) will also be discussed.

Common psychiatric syndromes and pharmacologic treatments of traumatic brain injury

Psychiatric syndromes are common in patients with traumatic brain injury. Patients may develop typical disorders of mood, anxiety, or psychosis, in addition to changes in personality and cognition. The frequency of these syndromes and potential pharmacologic treatments for these psychiatric syndromes are just coming to light. There are, unfortunately, a dearth of placebo-controlled trials to guide treatment, although numerous treatments are suggested in the literature. This article reviews the existing studies of clinical syndromes related to brain injury and possible pharmacologic treatments.

Neuropsychiatric Aspects of Traumatic Brain Injury

Traumatic brain injury (TBI) may produce a variety of neuropsychiatric problems, including impaired cognition, depression, mania, affective lability, irritability, anxiety, and psychosis. Despite the common occurrence of these symptoms following TBI, there are relatively few studies that provide clear guidance regarding management. Many symptoms (eg, irritability, affective lability, fatigue, sleep disturbance, and impaired cognition) are primarily consequences of brain injury rather than symptoms of a comorbid psychiatric disorder such as major depression. Although it is difficult to study the complicated treatments needed for such symptom complexes, we are able to recommend an approach to the evaluation and treatment of neuropsychiatric problems following traumatic brain injury. A thorough assessment of the patient is a prerequisite to the prescription of any treatment. This assessment should include a thorough developmental, psychiatric, and medication history; a detailed mental status examination; a complete neurologic examination; and quantification of neuropsychiatric symptoms using standardized and accepted inventories (eg, Neurobehavioral Rating Scale, Neuropsychiatric Inventory ). All symptoms must be evaluated in the context of the patient's premorbid history and current treatment because neuropsychiatric symptoms may be influenced by either factor or by both factors. Psychotherapy is an important component of the treatment of neuropsychiatric problems following TBI. Additionally, patients should be encouraged to become involved with local TBI support groups. When medications are prescribed, it is essential to use cautious dosing (low and slow) and empiric trials with continuous reassessment of symptoms using standardized scales and monitoring for drug-drug interactions. In general, medications with significant sedative, antidopaminergic, and anticholinergic properties should be avoided, and benzodiazepines should be used sparingly, if at all. Although patients with TBI may be particularly susceptible to adverse effects of psychopharmacologic medications, at times dosages similar to those used for the non-brain-injured psychiatric patient may be needed. When a single medication does not provide adequate relief of symptoms or cannot be tolerated at therapeutic doses, an alternative strategy is to augment the effect of one medication by using a second low-dose agent with a different mechanism of action.

Psychostimulant treatment of stroke and brain injury

Psychopharmacology is rapidly becoming an adjuvant treatment to traditional rehabilitation strategies for patients with stroke or brain injury because it helps to facilitate recovery in a time-efficient manner. Norepinephrine, dopamine, acetylcholine, and serotonin appear to play important roles in recovery from stroke or brain injury. Animal models have shown that blockade of these neurotransmitters inhibits recovery, whereas recovery is promoted by drugs that promote norepinephrine, dopamine, acetylcholine, and serotonin activity. Preliminary evidence from human trials supports these findings. Further study is needed, but expanded use of pharmacologic agents for stroke and brain-injured patients appears imminent.

Assessment of minimally responsive patients: clinical difficulties of single-case design

Improved management of very severely central nervous system (CNS) injured individuals has given rise to an increasing number of patients in a minimally responsive state. There is a growing literature stressing the importance of accurately determining these patients' level of cognitive functioning and its role in appropriate rehabilitation and long term management. The single case design model appears to be the intervention of choice, with its great flexibility and tailored approach to each individual case. The recent literature has focused on the technical aspects of the assessment, offering clear procedural guidelines. Unfortunately, there is a dearth of information about clinical factors such as clinical setting and family involvement, which may interfere with or prevent a planned intervention. The case of MT is presented, who was the subject of a single case intervention 9 months following an extremely severe traumatic brain injury. The planned intervention was to examine the effects of a psychostimulant on MT's level of arousal, in order to improve his participation in the rehabilitation programme. Beyond the results (which were equivocal), the clinical difficulties in conducting single case study designs in rehabilitation are discussed. Ways to minimize these difficulties are proposed.