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Following a total of 386 deep brain stimulation (DBS) procedures in Oxford, only two seizures have been recorded in the peri-operative period. Both patients had MS and underwent thalamic DBS for tremor and these 2 cases are presented here. The incidence of peri-operative seizures in MS patients undergoing DBS procedures is more than 8-fold greater than that expected for patients undergoing DBS procedures. Further experience with DBS procedures in MS patients is needed to determine whether there is a role for peri-operative anticonvulsants in these patients. [ABSTRACT FROM AUTHOR]

Background There is solid evidence of the long term efficacy of deep brain stimulation of the globus pallidus pars interna in the treatment of generalised dystonia. However there are conflicting reports concerning whether certain subgroups gain more benefit from treatment than others. We analysed the results of a series of 60 cases to evaluate the effects of previously proposed prognostic factors including dystonia aetiology, dystonia phenotype, age at onset of dystonia, and duration of dystonia prior to treatment. Methods 60 patients with medically intractable primary or secondary generalised dystonia were treated with deep brain stimulation of the globus pallidus pars interna during the period 1999-2010 at the Department of Neurosurgery in Oxford, UK. Patients were assessed using the Burke-Fahn-Marsden (BFM) Dystonia Rating Scale prior to surgery, 6 months after implantation and thereafter at 1 year, 2 years and 5 years follow-up. Results The group showed mean improvements in the BFM severity and disability scores of 43% and 27%, respectively, by 6 months, and this was sustained. The results in 11 patients with DYT gene mutations were significantly better than in non-genetic primary cases. The results in 12 patients with secondary dystonia were not as good as those seen in non-genetic primary cases but there remained a significant beneficial effect. Age of onset of dystonia, duration of disease prior to surgery, and myoclonic versus torsional disease phenotype had no significant effect on outcome. Conclusions The aetiology of dystonia was the sole factor predicting a better or poorer outcome from globus pallidus pars interna stimulation in this series of patients with generalised dystonia. However even the secondary cases that responded the least well had a substantial reduction in BFM scores compared with preoperative clinical assessments, and these patients should still be considered for deep brain stimulation. [ABSTRACT FROM AUTHOR]

Objectives To evaluate the efficacy of deep brain stimulation (DBS) in the treatment of tremor resulting from acquired brain injury (ABI). Methods A series of eight consecutive patients with post-ABI tremor were treated with DBS of the ventrooralis posterior (VOP)/zona incerta (ZI) region, and subsequently underwent blinded assessments using Bain's tremor severity scale. Results VOP/ZI DBS produced a mean reduction in tremor severity of 80.75% based on Bain's tremor severity scale, with significant reductions in all five component tremor subscores: rest, postural, kinetic, proximal and distal. No adverse neurological complications were reported, although one patient experienced exacerbation of pre-existing gait ataxia. Conclusion VOP/ZI stimulation is demonstrated here to be an effective and safe approach for the treatment of post-ABI tremor in the largest series published at the time of writing. [ABSTRACT FROM AUTHOR]

Abstract: We measured reaction times during a stop-signal task while patients with Parkinson''s disease were on and off unilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN). While reaction times to a “go” stimulus improved, there was no change in reaction times to the “stop” stimulus (SSRTs). However, changes in SSRTs induced by DBS were highly dependent on baseline SSRTs (measured off stimulation), with the greatest improvements being achieved by those with particularly slow reaction times. We therefore selected only those patients whose baseline SSRTs were within the limits of a control sample (N =10). In this group, SSRTs became slower when DBS was on. This finding suggests a role for the STN in response inhibition, which can be interrupted by DBS, observable only when more general improvements in Parkinson''s function are minimised. We also compared the effects of unilateral left and right sided stimulation. We found a greater increase in SSRTs after DBS of the left STN. [Copyright &y& Elsevier]

Abstract: Parkinson''s disease is treated pharmacologically with dopamine replacement medication and, more recently, by stimulating basal-ganglia nuclei such as the subthalamic nucleus (STN). Depth recordings after this procedure have revealed excessive activity at frequencies between 8 and 35 Hz () that are reduced by dopamine therapy in tandem with improvements in bradykinesia/rigidity, but not tremor (). It has also been shown that improvements in motor symptoms after dopamine correlate with single unit activity in the beta range (). We recorded local field potentials (LFPs) from the subthalamic nucleus of patients with Parkinson''s disease (PD) after surgery to implant deep brain stimulating electrodes while they were on and off dopaminergic medication. As well as replicating Kuhn et al., using the same patients we were able to extend Weinberger et al. to show that LFP beta oscillatory activity correlated with the degree of improvement in bradykinesia/rigidity, but not tremor, after dopamine medication. We also found that the power of beta oscillatory activity uniquely predicted improvements in bradykinesia/rigidity, but again not tremor, after stimulation of the STN in a regression analysis. However improvements after STN stimulation related inversely to beta power, possibly reflecting the accuracy of the electrode placement and/or the limits of STN stimulation in patients with the greatest levels of beta oscillatory activity. [Copyright &y& Elsevier]

Deep brain stimulation (DBS) of the pedunculopontine nucleus (PPN) is a novel neurosurgical therapy developed to address symptoms of gait freezing and postural instability in Parkinson's disease and related disorders. Here, we summarize our non-human primate and neuroimaging research of relevance to our surgical targeting of the PPN. We also describe our clinical experience of PPN DBS with greatest motor improvements achieved by stimulation at low frequencies. [ABSTRACT FROM AUTHOR]

In the current era of functional surgery for movement disorders, deep brain stimulation (DBS) of the globus pallidus internus (GPi) is emerging as the favoured intervention for patients with dystonia. Here we report our results in 20 patients with medically intractable dystonia treated with GPi stimulation. The series comprised 14 patients with generalized dystonia and six with spasmodic torticollis. Although comparisons were limited by differences in their respective neurological rating scales, chronic DBS clearly benefited both patient groups. Data conveying the rate of change in neurological function following intervention are also presented, demonstrating the gradual but progressive and sustained nature of improvement following stimulation of the GPi in dystonic patients. [ABSTRACT FROM AUTHOR]