Neurology
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Extrapyramidal motor symptoms precede dementia in Parkinson disease (PDD) by many years, whereas dementia occurs early in dementia with Lewy bodies (DLB). Despite this clinical distinction, the neuropsychological and neuropathologic features of these conditions overlap. In addition to widespread distribution of Lewy bodies, both diseases have variable burdens of neuritic plaques and neurofibrillary tangles characteristic of Alzheimer disease (AD). ⋯ Global cortical amyloid burden is high in dementia with Lewy bodies (DLB) but low in Parkinson disease dementia. These data suggest that beta-amyloid may contribute selectively to the cognitive impairment of DLB and may contribute to the timing of dementia relative to the motor signs of parkinsonism.
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To assess in patients with late-onset idiopathic restless legs syndrome (RLS) the brain iron content with magnetic resonance relaxometry, and brain activation during dorsiflexion and plantar flexion of both feet, using fMRI. ⋯ Late-onset restless legs syndrome is associated with low iron content of the basal ganglia and increased activity of the dorsolateral prefrontal cortex.
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Randomized Controlled Trial Comparative Study
Pain relief by rTMS: differential effect of current flow but no specific action on pain subtypes.
To assess, against placebo, the pain-relieving effects of high-rate repetitive transcranial magnetic stimulation (rTMS) on neuropathic pain. ⋯ Posteroanterior repetitive transcranial magnetic stimulation (rTMS) was more effective than both placebo and lateromedial rTMS. When obtained, pain relief was not specific of any particular submodality, but rather reduced the global pain sensation whatever its type. This is in accord with recent models of motor cortex neurostimulation, postulating that its analgesic effects may derive in part from modulation of the affective appraisal of pain, rather than a decrease of its sensory components.
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The immediate effects of deep brain stimulation (DBS) on subcortical neurons of its target region are controversial. ⋯ The data demonstrate that deep brain stimulation (DBS) induced metabolic activation of the subthalamic region and the directly connected globus pallidus which is in line with local and remote excitation of neurons by high frequency stimulation. These PET findings most likely reflect tonic driving of the DBS target area and its projection sites via ortho- and antidromic fiber conduction. We conclude that subthalamic nucleus DBS has predominant excitatory properties and does, therefore, fundamentally differ from lesional neurosurgery.