Brain : a journal of neurology
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Employing [(18)F]fluorodeoxyglucose (FDG) and PET, we have found previously that stereotaxic ablation of the internal globus pallidus (GPi) for Parkinson's disease causes resting metabolic changes in brain regions remote from the lesion site. In this study we determined whether similar metabolic changes occur in Parkinson's disease patients treated with deep brain stimulation (DBS) of the GPi. We studied seven Parkinson's disease patients with FDG-PET to measure resting regional cerebral glucose utilization on and off GPi stimulation. ⋯ GPi DBS improved UPDRS motor ratings (36%, P < 0.001) and significantly increased regional glucose metabolism in the premotor cortex ipsilateral to stimulation and in the cerebellum bilaterally. GPi DBS also resulted in a significant (P < 0.01) decline in PDRP activity ipsilateral to stimulation, which correlated significantly with clinical improvement in UPDRS motor ratings (P < 0.03). Clinical improvement with GPi DBS is associated with reduced expression of an abnormal Parkinson's disease-related metabolic network involving elements of the cortico-striato-pallido-thalamocortical and the cerebello-cortical motor loops.
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Certain patients with balance disorders report a 'visual vertigo' in which their symptoms are provoked or aggravated by specific visual contexts (e.g. supermarkets, driving or movement of objects). In order to determine the causes of visual vertigo (VV), we assessed symptoms, anxiety and the influence of disorienting visual stimuli in 21 such patients. In 17 out of 21 patients, a peripheral vestibular disorder was diagnosed. ⋯ VV is not related to trait anxiety or a past history of motion sickness. The results indicate that VV emerges in vestibular patients if they have increased visual dependence and difficulty in resolving conflict between visual and vestibulo-proprioceptive inputs. It is argued that treating these patients with visual motion desensitization, e.g. repeated optokinetic stimulation, should be beneficial.