Neurology
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People with complex regional pain syndrome type 1 (CRPS1) watched a reflected image of their unaffected limb being touched and felt pain or paresthesia at the corresponding site on the affected limb. The authors suggest that allodynia and paresthesia can be mediated by the brain and that dysynchiria has implications for the understanding and management of CRPS1.
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The spread of chronic pain from its initial site of presentation is common, but the mechanisms of the spread are unknown. Here the authors present neurophysiologic evidence of altered interhemispheric conduction in a patient with a mirror-like spread of complex regional pain syndrome symptoms.
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High levels of beta-methylamino-l-alanine (BMAA), a putative neurotoxin, have been reported in brain samples from Chamorros and patients with Alzheimer disease (AD) from western Canada. The authors assayed free BMAA in the brains of five control subjects and five patients with AD from the US Pacific Northwest as well as Chamorros with and without Parkinson-dementia complex. In contrast to others, they detected no free BMAA in any of these samples.
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The intracarotid amobarbital (Wada) test can be used to evaluate hemispheric memory capacity before anterior temporal lobectomy (ATL). Most patients demonstrate better memory with injection ipsilateral to planned resection (expected asymmetry [EA]), but a substantial minority show better memory with contralateral injection (unexpected asymmetry [UA]). Both degree and direction of Wada memory asymmetry (WMA) have been associated with worse surgical outcome in small series. Reports also suggest that UA is associated with greater decline in verbal memory after left ATL (L-ATL). ⋯ Unexpected asymmetry is uncommon in patients with right anterior temporal lobectomy (R-ATL) and may be a risk marker of poor surgical outcome. This relationship may be obscured by language confounds in patients with L-ATL. The results suggest that Wada asymmetry (using mixed stimuli) does not predict postoperative verbal memory; it is unclear whether this finding is generalizable to centers using only nonverbal stimuli.
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To elucidate the involvement of the human subthalamic nucleus (STN) region in the processing or transmission of emotional information. ⋯ The delayed modulation of alpha activity recorded from the area of the subthalamic nucleus in PD may reflect the processing or transmission of information related to emotional stimuli. "Limbic" activation in the region of the subthalamic nucleus may explain why high-frequency stimulation of the subthalamic nucleus alters affect in some patients with PD.