Handbook of clinical neurology
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Declaration of brain death requires demonstration of irreversible injury to the whole brain including the brainstem. Current guidelines rely on bedside clinical examination to determine that the patient has irreversible coma, absent cranial nerve reflexes, and apnea. Neurophysiologic testing to support the clinical diagnosis of brain death has primarily consisted of EEG and evoked potentials-typically a combination of somatosensory evoked potential and brainstem auditory evoked potential. ⋯ Clinical scenarios in which neurophysiologic testing may aid the declaration of brain death include equivocal results of clinical examination findings, inability to perform some aspects of the neurologic examination, concern for residual sedative effects, suspected spinal cord or neuromuscular injury, and posterior fossa lesions with brainstem involvement. In these scenarios, EEG and evoked potentials may offer supportive evidence for irreversible injury to the whole brain. This chapter also discusses differences between current adult and pediatric guidelines for the role of ancillary testing in brain death.
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Palliative care is an approach to the care of patients, affected by serious illness, and their families that aims to reduce suffering through the management of medical symptoms, psychosocial issues, spiritual well-being, and setting goals of care. Patients and families affected by a neurodegenerative illness have significant palliative care needs beginning at the time of diagnosis and extending through end-of-life care and bereavement. We advocate an approach to addressing these needs where the patient's primary care provider or neurologist plays a central role. ⋯ Managing distressing medical and psychiatric symptoms is critical to improving quality of life throughout the disease course as well as at end-of-life. Many symptoms are common across illnesses; however, there are issues that are specific to the most common classes of neurodegenerative illness, namely dementia, parkinsonism, and motor neuron disease. Incorporating a palliative approach to care, although challenging in many ways, empowers physicians to provide greater support and guidance to patients and families in making the difficult journey through a neurodegenerative illness.
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Magnetoencephalography (MEG) is the noninvasive measurement of the miniscule magnetic fields produced by electrical currents flowing in the brain-the same neuroelectric activity that produces the EEG. MEG is one of several diagnostic tests employed in the evaluation of patients with epilepsy, but without the need to expose the patient to any potentially harmful agents. MEG is especially important in those being considered for epilepsy surgery, in whom accurate localization of the epileptic focus is paramount. ⋯ Signal processing and clinical interpretation in magnetoencephalography require sophisticated noise reduction and computerized mathematical modeling. Technological advances in these areas have brought MEG to the point where it is now part of routine clinical practice. MEG has become an indispensable part of the armamentarium at epilepsy centers where MEG laboratories are located, especially when patients are MRI-negative or where results of other structural and functional tests are not entirely concordant.
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Tinnitus is the sensation of hearing a sound with no external auditory stimulus present. It is a public health issue correlated with multiple comorbidities and precipitating factors such as noise exposure, military service, and traumatic brain injury, migraine, insomnia, small vessel disease, smoking history, stress exposure, anxiety, depression, and socioeconomic status. ⋯ Forward management of this disorder should take this body of research into consideration as tinnitus remains a challenging condition to evaluate and treat with current management protocols still symptomatic at best. With a better understanding of the etiologic factors and comorbidities of tinnitus, additional research trials and new therapeutic approaches could see the light to tackle this public health disability bringing hope to patients and doctors.
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Delirium is an acute and transient brain dysfunction that is characterized by disturbances in consciousness, affecting both its content (i.e., attention) and level (i.e., arousal). It affects as many as 50% of those admitted to an intensive care unit (ICU). Once believed to be an inconsequential outcome of critical illness, it is now recognized that delirium is harmful in both the short- and long-term. ⋯ Nonpharmacologic strategies such as those which seek to reduce sensory impairment, sleep deprivation, and immobility are effective. Pharmacologic treatment with antipsychotics, though commonly used, is not supported by findings from placebo-controlled trials. Recent data support from multiple trials support the use of the "ABCDEF bundle" as a means by which to reduce delirium.