Rinshō shinkeigaku = Clinical neurology
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Anti-glycine receptor (anti-GlyR) antibodies were first reported in 2008 in a case of progressive encephalomyelitis with myoclonus and rigidity (PERM), which is a variant of stiff-person syndrome (SPS). After that, the antibodies have been studied extensively. At least 40 patients have been reported or presented until May 2013. ⋯ Twenty-one patients (75%) treated with immunotherapy or thymectomy improved, but two of six patients without immunotherapy died or developed cardiac arrest. The clinical features suggested that antibody-mediated inhibition of the GlyR on the brainstem nuclei or spinal inhibitory interneurons may cause continuous firing of α motor neurons and paroxysmal excessive response to a variety of afferent impulses, leading to increased stiffness, brainstem signs, trismus, myoclonus, painful spasms or hyperekplexia. Phenotype associated with the anti-GlyR antibodies may be broader than previously thought, but among those PERM is the most common phenotype.
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Neuralgic amyotrophy (NA, also known as Parsonage-Turner syndrome) is a distinct peripheral nervous system (PNS) disorder, characterized by sudden attacks of severe neuropathic pain usually in the shoulder and/or arm. The neuralgia commonly disappears after a few days to weeks, and consequently patchy paresis with amyotrophy appears. The available evidence suggests that NA is essentially idiopathic immune-mediated neuritis of the brachial plexus, and also has a complex pathogenesis that includes an underlying predisposition, susceptibility to dysfunction of some PNS structure, and a trigger for the attacks, such as viral infection, vaccination, trauma, surgery, and strenuous exercise. ⋯ However, recent studies have indicated that the long-term prognosis of NA is less favorable than has been assumed. In 2009, a Cochrane review identified one open label, retrospective series, the results of which suggested that administration of corticosteroids in the acute phase of NA could shorten the duration of painful symptoms and also accelerate recovery in some patients. We recently have reported that intravenous immunoglobulin (IVIg) with methylpredonisolone pulse therapy is effective for motor impairment of NA.
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Isaacs' syndrome is an antibody-mediated potassium channel disorder. Clinical symptoms of Isaacs' syndrome are characterized by muscle cramp, slow relaxation following muscle contraction, and hyperhidrosis. Hyperexcitability of the peripheral nerve cause these symptoms, which are relieved by administration of Na channel blockers and immunotherapy. ⋯ The "VGKC antibodies" are now usually known as VGKC-complex antibodies. In general, LGI-1 antibodies are most common in limbic encephalitis with SIADH. CASPR-2 antibodies are present in the majority of patients with Morvan syndrome.
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Review
Mechanism of action for deep brain stimulation and electrical neuro-network modulation (ENM).
Deep brain stimulation (DBS) has become an important treatment option for carefully screened medication resistant neurological and neuropsychiatric disorders. DBS therapy is not always applied deep to the brain; does not have to be applied exclusively to the brain; and the mechanism for DBS is not simply stimulation of structures. The applications and target locations for DBS devices are rapidly expanding, with many new regions of the brain, spinal cord, peripheral nerves, and muscles now possibly accessed through this technology. We will review the idea of "electrical neuro-network modulation (ENM)"; discuss the importance of the complex neural networks underpinning the effects of DBS; discuss the expansion of brain targets; discuss the use of fiber based targets; and discuss the importance of tailoring DBS therapy to the symptom, rather than the disease.
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Deep brain stimulation (DBS) has been widely performed for various medically refractory movement disorders. For Parkinson disease (PD), target of DBS is subthalamic nucleus (STN) or globus pallidus internus (GPi). There are some evidences to demonstrate its effectiveness on motor function and QOL. ⋯ DBS of Vim thalamus has been indicated for intractable tremor with various etiologies. Recently posterior subthalamic area (PSA) is introduced as an alternative target to Vim for tremor. GPi DBS is also effective treatment option for generalized dystonia.