Handbook of clinical neurology
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Recent progress in serological screening of paraneoplastic antibodies and in diagnostic imaging techniques to detect malignancies has enabled a broadening of the concept of paraneoplastic neurological syndromes by integrating nonclassic clinical features. The peripheral nervous system is frequently involved in patients with paraneoplastic syndrome and may be seen alone or in combination with involvement of other areas of the nervous system. Destruction of dorsal root ganglion cells due to lymphocytic infiltration, especially with CD8-positive cytotoxic T cells, has been postulated to mediate the classic syndrome of subacute sensory neuronopathy. ⋯ Somatic neuropathy is the most common manifestation in patients with anti-Hu and anti-CV2/CRMP-5 antibodies, while anti-ganglionic acetylcholine receptor antibody is associated with autonomic neuropathies. A whole-body fluorodeoxyglucose positron emission tomography scan may be useful to detect malignancy in patients with unremarkable conventional radiological findings. Recognition and diagnosis of paraneoplastic neuropathy is important, as neuropathic symptoms usually precede the identification of the primary tumor, and treatment at an earlier stage provides better chances of good outcomes.
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This chapter summarizes progress in the evaluation of peripheral nerve (PN) lesions and disorders by imaging techniques encompassing magnetic resonance imaging (MRI) and nerve ultrasound (US). Due to the radiation exposure and limited sensitivity in soft tissue contrast, computed-tomography (CT) plays no significant role in the diagnostic work-up of PN disorders. MRI and US are complementary techniques for the evaluation of peripheral nerves, each having particular advantages and disadvantages. ⋯ In experimental settings, novel molecular and cellular MRI contrast agents allow in-vivo assessment of nerve regeneration as well as monitoring of neuroinflammation. Depending on further clinical development, contrast-enhanced MRI has the potential to follow cellular responses over time in vivo and to overcome the current limitations of histological assessment of nerve afflictions. Further advances in contrast-enhanced US has the potential for developing into a tool for the assessment of nerve blood perfusion, paving the way for better assessments of ischemic neuropathies.
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Whereas there is no specific neurosurgical technique in pediatric epilepsy, the frequency of each type of surgery is very different from epilepsy surgery applied in adults, and reflects the underlying etiologies, which are much more diverse in children, with malformations of cortical development and tumors as the prevailing etiologies. Extensive resective or disconnective procedures for extratemporal epilepsy are more frequently performed in infants and younger children, whereas temporo-mesial resection is by far the most common surgical treatment for adults with epilepsy. More recently, less invasive techniques in children with an extensive epileptogenic zone, such as multilobar disconnection, hemispherotomy and other functional hemispherectomy variants, have been introduced in order to reduce duration of surgery, perioperative morbidity and length of hospital stay. ⋯ This development has been encouraged with the introduction of image-guided navigation systems for the preoperative planning and during surgery. Historically, epilepsy surgery for children has been established much later than for adults. Apart from the particular aspects in perioperative management of younger infants, surgery-related morbidity as well as seizure outcome is in general similar to those in adults, depending rather on each type of surgery.
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Noninvasive brain stimulation (NIBS) is a unique method for studying cognitive function. For the study of cognition, NIBS has gained popularity as a complementary method to functional neuroimaging. By bypassing the correlative approaches of standard imaging techniques, it is possible to establish a putative relationship between brain cognition. ⋯ Moreover, an important factor is the possible interactions between these factors and the physiological and cognitive state of the subject. To use NIBS in cognition, it is important to understand not only how NIBS functions but also the brain mechanisms being studied and the features of the area of interest. To describe better the advanced knowledge provided by NIBS in cognition, we will treat each NIBS technique separately and underline the related hypotheses beyond applications.
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Disorders of cognition are a major societal burden. As the population grows and ages, these conditions demand urgent attention, as healthcare resources stretch to accommodate the growing number of patients. ⋯ By targeting specific structures within known circuits, deep brain stimulation (DBS) can have effects across memory and cognitive networks, and is therefore a potentially promising avenue for novel dementia treatments. This chapter reviews the literature on DBS for AD and dementia associated with Parkinson's disease, and highlight some of the neuroanatomical targets that offer the most promise in modulating the underlying pathological activity in brain circuitry.