Gilles de la Tourette syndrome and deep brain stimulation
ABSTRACT Gilles de la Tourette Syndrome (GTS) is characterized by multiple motor and one or more vocal/phonic tics. Psychopathology and co-morbidity occur in approximately 80-90% of clinical cohorts. The most common psychopathologies are attention deficit hyperactivity disorder, obsessive-compulsive behaviours, obsessive-compulsive disorder, depression, anxiety and certain behavioural disorders. In severe GTS patients who are refractory to medication and other therapies, deep brain stimulation (DBS) is investigated. To date there have been some 50-55 patients who have received DBS in 19 centres worldwide. Nine different brain targets in the thalamus, the pallidum, and the ventral caudate and anterior internal capsule have been stimulated. This paper reviews critically and in detail all studies published to date. Only two studies on just a few patients fulfil some of the evidence-based criteria. DBS for GTS is therefore still highly experimental.
- SourceAvailable from: Domenico ServelloFrontiers in Integrative Neuroscience 06/2011; 5:22. DOI:10.3389/fnint.2011.00022
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ABSTRACT: The basal ganglia (BG) are a group of subcortical structures involved in diverse functions, such as motor, cognition and emotion. However, the BG do not control these functions directly, but rather modulate functional processes occurring in structures outside the BG. The BG form multiple functional loops, each of which controls different functions with similar architectures. Accordingly, to understand the modulatory role of the BG, it is strategic to uncover the mechanisms of signal processing within specific functional loops that control simple neural circuits outside the BG, and then extend the knowledge to other BG loops. The saccade control system is one of the best-understood neural circuits in the brain. Furthermore, sophisticated saccade paradigms have been used extensively in clinical research in patients with BG disorders as well as in basic research in behaving monkeys. In this review, we describe recent advances of BG research from the viewpoint of saccade control. Specifically, we account for experimental results from neuroimaging and clinical studies in humans based on the updated knowledge of BG functions derived from neurophysiological experiments in behaving monkeys by taking advantage of homologies in saccade behavior. It has become clear that the traditional BG network model for saccade control is too limited to account for recent evidence emerging from the roles of subcortical nuclei not incorporated in the model. Here, we extend the traditional model and propose a new hypothetical framework to facilitate clinical and basic BG research and dialogue in the future.European Journal of Neuroscience 06/2011; 33(11):2070-90. DOI:10.1111/j.1460-9568.2011.07691.x · 3.67 Impact Factor
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ABSTRACT: Deep brain stimulation (DBS) has become a treatment for a growing number of neurological and psychiatric disorders, especially for therapy-refractory Parkinson's disease (PD). However, not all of the symptoms of PD are sufficiently improved in all patients, and side effects may occur. Further progress depends on a deeper insight into the mechanisms of action of DBS in the context of disturbed brain circuits. For this, optimized animal models have to be developed. We review not only charge transfer mechanisms at the electrode/tissue interface and strategies to increase the stimulation's energy-efficiency but also the electrochemical, electrophysiological, biochemical and functional effects of DBS. We introduce a hemi-Parkinsonian rat model for long-term experiments with chronically instrumented rats carrying a backpack stimulator and implanted platinum/iridium electrodes. This model is suitable for (1) elucidating the electrochemical processes at the electrode/tissue interface, (2) analyzing the molecular, cellular and behavioral stimulation effects, (3) testing new target regions for DBS, (4) screening for potential neuroprotective DBS effects, and (5) improving the efficacy and safety of the method. An outlook is given on further developments of experimental DBS, including the use of transgenic animals and the testing of closed-loop systems for the direct on-demand application of electric stimulation.04/2011; 2011:414682. DOI:10.4061/2011/414682