Handbook of clinical neurology
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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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Dystonia is a heterogeneous disorder characterized by involuntary muscle contractions, twisting movements, and abnormal postures in various body regions. It is widely accepted that the basal ganglia are involved in the pathogenesis of dystonia. ⋯ Several clinical observations, including those from secondary dystonia cases as well as neurophysiologic and neuroimaging studies in human patients, provide further evidence in humans of a possible relationship between cerebellar abnormalities and dystonia. Claryfing the role of the cerebellum in dystonia is an important step towards providing alternative treatments based on noninvasive brain stimulation techniques.
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Postconcussion syndrome (PCS) is a heterogeneous condition comprised of a set of signs and symptoms in somatic, cognitive, and emotional domains. PCS is a controversial concept because of differing consensus criteria, variability in presentation, and lack of specificity to concussion. Whereas symptoms of concussion resolve in most individuals over days to weeks, a minority of individuals experience symptoms persisting months to years. ⋯ Successful treatment requires thoughtful differential diagnosis, including consideration of comorbid and premorbid conditions and other possible contributing factors. Treatment should include a hierarchic, sequential approach to management of treatable symptoms that impact functioning, such as depression, anxiety, insomnia, headache, musculoskeletal pain, and vertigo. A guided prescription of aerobic exercise is beneficial for early- and late-phase disorders after concussion.
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Tens of millions of children and adults participate in organized sport in the United States each year. Although uncommon, fatal and severe nonfatal brain and spine injuries can occur during these activities. These "catastrophic" injuries have been noted in contact sports such as football, rugby, and ice hockey, as well as in noncontact sports including baseball, cheerleading, swimming and diving, equestrian, gymnastics, pole vault, rodeo, snow skiing, snowboarding, and wrestling. ⋯ Participating in sport provides many benefits to physical and mental health. Despite these benefits, rare devastating injuries can be traumatic for the athletes, their families, and communities and can raise safety concerns that may reduce participation in sport. Understanding and preventing these types of injuries are critical to fostering participation in sport and ensuring both children and adults reap the physical, social, and mental benefits of sport.