Ten-Year Outcome of Subthalamic Stimulation in Parkinson Disease
ABSTRACT To assess the 10-year motor outcome of deep brain stimulation of the subthalamic nucleus (STN-DBS) in patients with Parkinson disease (PD).
Patients with PD with bilateral STN-DBS were assessed according to the Core Assessment Program for Surgical Interventional Therapies in Parkinson's Disease protocol and videotaped at baseline and 1, 5, and 10 years after surgery. An independent rater blinded to stimulation and medication condition scored the 10-year video assessments.
Movement Disorders Centre, Toronto Western Hospital, University Health Network, University of Toronto.
Eighteen patients with advanced PD and 10-year follow-up of STN-DBS.
Bilateral STN-DBS surgery.
The primary outcome was the change in blinded Unified Parkinson's Disease Rating Scale (UPDRS) motor scores/subscores between the no medication/stimulation condition vs the no medication/no stimulation condition at 10 years. Secondary outcomes were the changes in blinded UPDRS motor scores between the medication/no stimulation and medication/stimulation conditions, UPDRS II scores, UPDRS IV dyskinesia and motor fluctuations scores, and anti-PD medication dose (levodopa equivalent daily dose) at different points.
In the 18 patients available for follow-up at 10 years, STN-DBS still significantly improved the UPDRS total motor score (P = .007) and resting and action tremor (P < .01 and P = .02, respectively) and bradykinesia (P = .01) subscores. The UPDRS II scores in the medication and no medication conditions, UPDRS IV dyskinesia and motor fluctuations scores, and the levodopa equivalent daily dose were also significantly reduced compared with baseline. Axial signs showed the most progressive decline in stimulation and levodopa response over the years.
This class III study provides evidence that stimulation-induced motor improvement was sustained overall at 10 years, although part of the initial benefit wore off mainly because of progressive loss of benefit on axial signs over time.
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ABSTRACT: Inhibition of inappropriate, habitual or prepotent responses is an essential component of executive control and a cornerstone of self-control. Via the hyperdirect pathway, the subthalamic nucleus (STN) receives inputs from frontal areas involved in inhibition and executive control. Evidence is reviewed from our own work and the literature suggesting that in Parkinson's disease (PD), deep brain stimulation (DBS) of the STN has an impact on executive control during attention-demanding tasks or in situations of conflict when habitual or prepotent responses have to be inhibited. These results support a role for the STN in an inter-related set of processes: switching from automatic to controlled processing, inhibitory and executive control, adjusting response thresholds and influencing speed-accuracy trade-offs. Such STN DBS-induced deficits in inhibitory and executive control may contribute to some of the psychiatric problems experienced by a proportion of operated cases after STN DBS surgery in PD. However, as no direct evidence for such a link is currently available, there is a need to provide direct evidence for such a link between STN DBS-induced deficits in inhibitory and executive control and post-surgical psychiatric complications experienced by operated patients.Frontiers in Systems Neuroscience 12/2013; 7:118. DOI:10.3389/fnsys.2013.00118
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ABSTRACT: High-frequency deep brain stimulation is used to treat a wide range of brain disorders, like Parkinson's disease. The stimulated networks usually share common electrophysiological signatures, including hyperactivity and/or dysrhythmia. From a clinical perspective, HFS is expected to alleviate clinical signs without generating adverse effects. Here, we consider whether the classical open-loop HFS fulfills these criteria and outline current experimental or theoretical research on the different types of closed-loop DBS that could provide better clinical outcomes. In the first part of the review, the two routes followed by HFS-evoked axonal spikes are explored. In one direction, orthodromic spikes functionally de-afferent the stimulated nucleus from its downstream target networks. In the opposite direction, antidromic spikes prevent this nucleus from being influenced by its afferent networks. As a result, the pathological synchronized activity no longer propagates from the cortical networks to the stimulated nucleus. The overall result can be described as a reversible functional de-afferentation of the stimulated nucleus from its upstream and downstream nuclei. In the second part of the review, the latest advances in closed-loop DBS are considered. Some of the proposed approaches are based on mathematical models, which emphasize different aspects of the parkinsonian basal ganglia: excessive synchronization, abnormal firing-rate rhythms, and a deficient thalamo-cortical relay. The stimulation strategies are classified depending on the control-theory techniques on which they are based: adaptive and on-demand stimulation schemes, delayed and multi-site approaches, stimulations based on proportional and/or derivative control actions, optimal control strategies. Some of these strategies have been validated experimentally, but there is still a large reservoir of theoretical work that may point to ways of improving practical treatment.Frontiers in Systems Neuroscience 12/2013; 7:112. DOI:10.3389/fnsys.2013.00112
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ABSTRACT: The technology of Neural Stimulation in recent years has become the focus of the research and treatment, although it has been around for many years. The potential use of stimulating the brain and nerves ranges from the spinal cord stimulation to the implantations of cochlear and bionic eyes with a large discrepancy between the clinical readiness for these various uses. Electrical high-frequency Deep Brain Stimulation (DBS) was developed as an alternative option to treat a few neurological disorders. However, with advancing in surgical procedures, technologies and safeties, the applications of DBS are expanding not only for therapeutic purposes but also for research. Although the exact mechanisms of action/s are not fully understood, the outcome of the ongoing research and clinical trials are promising. DBS has been used to treat the essential tremor since 1997, Parkinson's disease (PD) since 2002 and dystonia since 2003. It has also been used to treat various disorders, including major depression. The therapeutic effect of DBS in PD is well established but for other diseases such as epilepsy the outcomes are unclear and ambiguous. This article is a succinct review of the literature, focusing on PD, epilepsy and Obsessive Compulsive Disorder (OCD).Autonomic neuroscience: basic & clinical 08/2013; 4(3):84-88. · 1.37 Impact Factor