Handbook of clinical neurology
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The diagnosis of brain death should be based on a simple premise. If every possible confounder has been excluded and all possible treatments have been tried or considered, irreversible loss of brain function is clinically recognized as the absence of brainstem reflexes, verified apnea, loss of vascular tone, invariant heart rate, and, eventually, cardiac standstill. This condition cannot be reversed - not even partly - by medical or surgical intervention, and thus is final. ⋯ Generally, the concept of brain death has been accepted by all major religions. But patients' families may have different ideas and are mostly influenced by cultural attitudes, traditional customs, and personal beliefs. Suggestions are offered to support these families.
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Neurorehabilitation is based on the assumption that motor learning contributes to motor recovery after injury. However, little is known about how learning itself is affected by brain injury, how learning mechanisms interact with spontaneous biological recovery, and how best to incorporate learning principles into rehabilitation training protocols. Here we distinguish between two types of motor learning, adaptation and skill acquisition, and discuss how they relate to neurorehabilitation. ⋯ The emphasis in current neurorehabilitation practice is on the rapid establishment of independence in activities of daily living through compensatory strategies, rather than on the reduction of impairment. Animal models, however, show that after focal ischemic damage there is a brief, approximately 3-4-week, window of heightened plasticity, which in combination with training protocols leads to large gains in motor function. Analogously, almost all recovery from impairment in humans occurs in the first 3 months after stroke, which suggests that targeting impairment in this time-window with intense motor learning protocols could lead to gains in function that are comparable in terms of effect size to those seen in animal models.
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Stroke is the major cause of long-term disability worldwide, with impaired manual dexterity being a common feature. In the past few years, noninvasive brain stimulation (NIBS) techniques, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), have been investigated as adjuvant strategies to neurorehabilitative interventions. These NIBS techniques can be used to modulate cortical excitability during and for several minutes after the end of the stimulation period. ⋯ Differential modulation of cortical excitability in the affected and unaffected hemisphere of patients with stroke may induce plastic changes within neural networks active during functional recovery. The aims of this chapter are to describe results from these proof-of-principle trials and discuss possible putative mechanisms underlying such effects. Neurophysiological and neuroimaging changes induced by application of NIBS are reviewed briefly.
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Epilepsies associated with inborn errors of metabolism (IEM) represent a major challenge. Seizures rarely dominate the clinical presentation, which is more frequently associated with other neurological symptoms, such as hypotonia and/or cognitive disturbances. Although epilepsy in IEM can be classified in various ways according to pathogenesis, age of onset, or electroclinical presentation, the most pragmatic approach is determined by whether they are accessible to specific treatment or not. ⋯ Folinic acid-dependent seizures are allelic with pyridoxine dependency. Incompletely treatable IEMs include pyridoxal phosphate, serine, and creatine deficiencies. The main IEMs that present with epilepsy but offer no specific treatment are nonketotic hyperglycinemia, mitochondrial disorders, sulfite oxidase deficiency, ceroid-lipofuscinosis, Menkes disease, and peroxisomal disorders.
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Clinical ethics is the application of ethical theories, principles, rules, and guidelines to clinical situations in medicine. Therefore, clinical ethics is analogous to clinical medicine in that general principles and concepts must be applied intelligently and thoughtfully to unique clinical circumstances. The three major ethical theories are consequentialism, whereby the consequences of an action determine whether it is ethical; deontology, whereby to be ethical is to do one's duty, and virtue ethics, whereby ethics is a matter of cultivating appropriate virtues. ⋯ According to principlism, the medical practitioner must attempt to uphold four important principles: respect for patient autonomy, beneficence, nonmaleficence, and justice. When these principles conflict, resolving them depends on the details of the case. Alternative approaches to medical ethics, including the primacy of beneficence, care-based ethics, feminist ethics, and narrative ethics, help to define the limitations of principlism and provide a broader perspective on medical ethics.