Baillière's clinical neurology
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At present, there are three major surgical approaches to Parkinson's disease (PD): (1) Ablative surgery (i.e. pallidotomy, thalamotomy); (2) deep brain stimulation (DBS) of the thalamus, internal globus pallidus (GPi) and subthalamic nucleus (STN); and (3) grafting fetal mesencephalic cells into the striatum. As a result of increasing understanding of the pathophysiology of the basal ganglia and the demonstration of surgical alleviation of experimental parkinsonism, surgery has regained a paramount importance in the management of PD. The aim of pallidotomy and DBS is to reduce the excessive inhibitory output from the GPi and substantia nigra reticulata (SNr). ⋯ At present, grafting of dopaminergic cells is perhaps best suited for patients with young-onset PD (less than 45 years old) who are at high risk of developing complications within a short time of beginning pharmacological treatment and in whom the idea of making lesions or implanting electrodes into the brain for decades seems less appealing. Consideration of surgery in any given patient should be weighed against the risks (about 1% mortality and 2-6% of severe morbidity-hemiplegia, cognitive deficit, speech problems, etc.) associated with these techniques. The development of better imaging methods and the growing expertise of multidisciplinary teams will undoubtedly make surgery for PD safer and more effective in the future.
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Baillieres Clin Neurol · Dec 1996
ReviewContraception, pregnancy and lactation in women with epilepsy.
Despite all of our advances women with epilepsy face obstacles when it comes to pregnancy and childbearing. Many of these obstacles are social, based on incorrect and inappropriate attitudes of the public towards persons with epilepsy. Unfortunately many of the uninformed public are health care providers. ⋯ The number of exposed women is so small that no pattern or estimates of risk can be determined at this time. Careful monitoring as is being performed by the Lamotrigine and North American Epilepsy and Pregnancy Registries will hopefully provide the necessary safety information in the near future. All of the risks aside, the majority of women with epilepsy can and will have healthy children.
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The use of AEDs in the management of epilepsy requires an ongoing risk-benefit analysis that attempts to maximize seizure control while minimizing adverse cognitive side-effects. Although the effects of other factors on cognition are generally greater than AED effects in patients with epilepsy, the cognitive effects of AEDs are of special concern because they are iatrogenically induced. Baseline evaluation of mental functioning is essential and should be repeated whenever a change in cognitive performance is suspected. ⋯ Initial studies with children and older adults suggest that the effects of the major AEDs are comparable across the developmental lifespan. However, during the formative years of a child's intellectual development, close scrutiny should be paid to the possibility that subtle attentional or arousal deficits could contribute to cumulative deficits in learning or memory. Preliminary studies involving both animals and humans suggest that the impact of AEDs might be greatest during in utero exposure; however, additional research is required to fully delineate the long-term effects of AED exposure in this earliest period of neurodevelopment.
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Vagus nerve stimulation (VNS) was first tried as a treatment for seizure patients in 1988. The idea to stimulate the vagus nerve and disrupt or prevent seizures was proposed by Jacob Zabarra. He observed a consistent finding among several animal studies which indicated that stimulation of the vagus nerve could alter the brain wave patterns of the animals under study. ⋯ The second is the concept that chronic stimulation of the vagus nerve increases the amount of inhibitory neurotransmitters and decreases the amount of excitatory neurotransmitters. Additional research into the optimal use of VNS is ongoing. Animal and clinical research have produced some interesting new data suggesting there are numerous ways to improve the clinical performance of vagus nerve stimulation as a treatment for refractory patients.
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Neuromuscular disorders are important causes of prolonged morbidity in intensive care unit. Specific disorders facing the neurologist in the intensive care unit may have been present before admission to the unit or develop as a secondary complication of their stay. ⋯ Among the neuromuscular disorders that confront the clinician in the unit are motor neuron disease, acute polyneuropathies including acute inflammatory demyelinating polyneuropathy (Guillain-Barré syndrome) and critical illness polyneuropathy, neuromuscular transmission disorders including myasthenia gravis, and specific myopathies. This chapter reviews the differential diagnosis and the unique features of neuromuscular conditions that may complicate critical illness and admission to the intensive care unit.