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201. Intraoperative motor-evoked potentials and pyramidal tractography for insular gliomas
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Society Proceedings / Clinical Neurophysiology 120 (2009) e9–e88
Methods: Six consecutive patients with refractory TS were included in an open prospective pilot study. DBS was performed in the nucleus accumbens in two patients and in the globus pallidus internus in two further patients. The remaining two patients were stimulated in thalamic structures and in the nucleus caudatus, respectively. The protocol included the Yale Global Tic Severity Scale (YGTSS) and video-based tic monitoring. Effects on comorbid psychiatric symptoms and side effects were carefully monitored. Results: During the observation period from 3 to 18 months application of DBS resulted in a substantial reduction of tics in three of the six patients (>50% improvement). Two patients had less than 50 % improvement and one patient was a nonresponder. None of the patients reported severe side effects. Conclusions: This open pilot study demonstrates the potential efficacy of DBS in different anatomic structures. It can therefore be assumed that these targets are integrated in the pathophysiology and dysregulated networks of TS. Our treatment results have to be discussed in the context of prior observations of DBS for TS and may help to elucidate the most effective target structure for this disorder. doi:10.1016/j.clinph.2008.07.196
199. Analysis of the temporal framework of within-object feature selection—M. Wachter 1, S. Hillyard 2, N. Nönnig 1, H.-J. Heinze 1,3, J.-M. Hopf 1,3, M. Schoenfeld 1,3 (1 Otto-von-Guericke Universitaet, Klinik fuer Neurologie 2, Magdeburg, Germany, 2 UCSD, Department of Neurosciences, La Jolla, CA, USA, 3 Leibniz Institut für Neurobiologie, Magdeburg, Germany) Objects typically consist of a variety of features that can selectively be attended to. Object-based theories of attention propose that the selection of one object feature leads to the rapid automatic selection of all other constituent features, regardless of their relevance to the task. Here we used magnetenephalographical recordings to investigate the temporal framework of within-object feature selection. The neurophysiological correlates indicate that the attentional selection of the feature motion of a moving colored transparent surface within an aperture lead first to the enhanced processing in motion related areas and about 40 ms later also in color related areas. Importantly, when the task changed and color was the attended feature enhanced processing was observed first in color and later in motion-related areas. These findings indicate that the rapid attentional selection of visual features within objects is highly flexible with the order of feature selection being determined by task demands. doi:10.1016/j.clinph.2008.07.197
200. Postural deficits in Parkinson’s disease are caused by insufficient feedback motor error correction and by deficits in sensory reweighting—C. Maurer (Universität Freiburg, Neurologie, Freiburg, Germany) The presence of postural instability separates mild Parkinson’s disease (PD) (Hoehn and Yahr stages 1 and 2) from moderate and severe PD (Hoehn and Yahr stages 3–5); quality of life inexorably deteriorates for patients with moderate or severe PD. Despite the severe consequences associated with falling and instability, the origin of these disturbances with relation to the motor control process is not understood. Methods: Here, we studied motor control of posture in a total of 16 PD patients under chronic subthalamic nucleus (STN) stimulation and 15 age-matched healthy control subjects using a model-based
approach. All experiments in PD patients were performed in a cross-over design (+/ STN stimulation, +/ L-Dopa). We exposed subjects to varying tilts of the support surface, using a pseudo-random waveform (PRTS, spectral bandwidth 0.05–10 Hz). Results: PD patients’ body excursions elicited by support surface tilts were smaller, but the response variability was larger compared to those of control subjects. When analyzing Transfer Functions between the input (support surface stimulus) and output (resulting body excursion) using a model based approach, we found that PD patients insufficiently use proprioceptive sensory information and over-weigh vestibular information, irrespective of the treatments tested. In addition, PD subjects suffer from a lack of flexibility when it comes to weighting the sensory information depending on external factors, again irrespective of treatments. Finally, we found that PD subjects’ corrective responses to externally generated tilts of the support surface were disturbed, in line with a dysfunction of feedback error correction. The latter deficit partially ameliorated with both STN stimulation and L-DOPA medication. Conclusions: We isolated treatment-independent and treatmentdependent deficits in motor control of PD posture. PD patients’ deficit in the sensory reweighting process leads to a high weight of the vestibular sensor signal, which is known to carry much more noise compared to the proprioceptive signal. This high noise level, in turn, may be responsible for the treatment-insensitive part of the postural control deficit in PD. On the other hand, the disturbed feedback error correction of PD subjects partially ameliorated with treatment. This deficit correlates with UPDRS-motor scores, representing patients partial benefit from treatment concerning their motor control of posture. doi:10.1016/j.clinph.2008.07.198
201. Intraoperative motor-evoked potentials and pyramidal tractography for insular gliomas—G. Neuloh 1, M. Nelles 2, H. Urbach 2, J. Schramm 1 (1 Universität Bonn, Neurochirurgische Klinik, Bonn, Germany, 2 Universität Bonn, Radiologische Klinik, Bonn, Germany) Objective: This prospective study examines the ability of intraoperative motor-evoked potentials (MEPs) to reflect ischemic involvement of the pyramidal tract, which is frequently observed with new paresis after insular glioma surgery. Methods: In a series of 45 insular gliomas, intraoperative MEP results were correlated with motor outcome and perioperative MR imaging including pyramidal tractography, FLAIR and diffusionweighted studies. Results: MEP deterioration indicated new paresis in 13 patients, and was reversible with only transient new deficit in 9 of these cases. The grade of MEP attenuation matched the clinical outcome and the morphological substrates of ischemic pyramidal tract involvement from mild edema to definite stroke. Conclusions: Intraoperative MEPs indicate motor tract ischemia in a staged way, as revealed by perioperative pyramidal tract imaging. Early intervention may avert the progression of transitory ischemia into definite stroke. doi:10.1016/j.clinph.2008.07.199
202. Nordic walking (pole striding) and depression—C. Willemer 1, K. Krüger 2, F.C. Mooren 2, K. Völker 3, S. Knecht 1, A. Flöel 1 (1 Universitäts-Klinikum Münster, Neurologie, Münster, Germany, 2 Universität Münster, Institut für Sportwissenschaft, Gießen, Germany, 3 Universität Gießen, Institut für Sportmedizin, Münster, Germany)
Society Proceedings / Clinical Neurophysiology 120 (2009) e9–e88
Methods: Six consecutive patients with refractory TS were included in an open prospective pilot study. DBS was performed in the nucleus accumbens in two patients and in the globus pallidus internus in two further patients. The remaining two patients were stimulated in thalamic structures and in the nucleus caudatus, respectively. The protocol included the Yale Global Tic Severity Scale (YGTSS) and video-based tic monitoring. Effects on comorbid psychiatric symptoms and side effects were carefully monitored. Results: During the observation period from 3 to 18 months application of DBS resulted in a substantial reduction of tics in three of the six patients (>50% improvement). Two patients had less than 50 % improvement and one patient was a nonresponder. None of the patients reported severe side effects. Conclusions: This open pilot study demonstrates the potential efficacy of DBS in different anatomic structures. It can therefore be assumed that these targets are integrated in the pathophysiology and dysregulated networks of TS. Our treatment results have to be discussed in the context of prior observations of DBS for TS and may help to elucidate the most effective target structure for this disorder. doi:10.1016/j.clinph.2008.07.196
199. Analysis of the temporal framework of within-object feature selection—M. Wachter 1, S. Hillyard 2, N. Nönnig 1, H.-J. Heinze 1,3, J.-M. Hopf 1,3, M. Schoenfeld 1,3 (1 Otto-von-Guericke Universitaet, Klinik fuer Neurologie 2, Magdeburg, Germany, 2 UCSD, Department of Neurosciences, La Jolla, CA, USA, 3 Leibniz Institut für Neurobiologie, Magdeburg, Germany) Objects typically consist of a variety of features that can selectively be attended to. Object-based theories of attention propose that the selection of one object feature leads to the rapid automatic selection of all other constituent features, regardless of their relevance to the task. Here we used magnetenephalographical recordings to investigate the temporal framework of within-object feature selection. The neurophysiological correlates indicate that the attentional selection of the feature motion of a moving colored transparent surface within an aperture lead first to the enhanced processing in motion related areas and about 40 ms later also in color related areas. Importantly, when the task changed and color was the attended feature enhanced processing was observed first in color and later in motion-related areas. These findings indicate that the rapid attentional selection of visual features within objects is highly flexible with the order of feature selection being determined by task demands. doi:10.1016/j.clinph.2008.07.197
200. Postural deficits in Parkinson’s disease are caused by insufficient feedback motor error correction and by deficits in sensory reweighting—C. Maurer (Universität Freiburg, Neurologie, Freiburg, Germany) The presence of postural instability separates mild Parkinson’s disease (PD) (Hoehn and Yahr stages 1 and 2) from moderate and severe PD (Hoehn and Yahr stages 3–5); quality of life inexorably deteriorates for patients with moderate or severe PD. Despite the severe consequences associated with falling and instability, the origin of these disturbances with relation to the motor control process is not understood. Methods: Here, we studied motor control of posture in a total of 16 PD patients under chronic subthalamic nucleus (STN) stimulation and 15 age-matched healthy control subjects using a model-based
approach. All experiments in PD patients were performed in a cross-over design (+/ STN stimulation, +/ L-Dopa). We exposed subjects to varying tilts of the support surface, using a pseudo-random waveform (PRTS, spectral bandwidth 0.05–10 Hz). Results: PD patients’ body excursions elicited by support surface tilts were smaller, but the response variability was larger compared to those of control subjects. When analyzing Transfer Functions between the input (support surface stimulus) and output (resulting body excursion) using a model based approach, we found that PD patients insufficiently use proprioceptive sensory information and over-weigh vestibular information, irrespective of the treatments tested. In addition, PD subjects suffer from a lack of flexibility when it comes to weighting the sensory information depending on external factors, again irrespective of treatments. Finally, we found that PD subjects’ corrective responses to externally generated tilts of the support surface were disturbed, in line with a dysfunction of feedback error correction. The latter deficit partially ameliorated with both STN stimulation and L-DOPA medication. Conclusions: We isolated treatment-independent and treatmentdependent deficits in motor control of PD posture. PD patients’ deficit in the sensory reweighting process leads to a high weight of the vestibular sensor signal, which is known to carry much more noise compared to the proprioceptive signal. This high noise level, in turn, may be responsible for the treatment-insensitive part of the postural control deficit in PD. On the other hand, the disturbed feedback error correction of PD subjects partially ameliorated with treatment. This deficit correlates with UPDRS-motor scores, representing patients partial benefit from treatment concerning their motor control of posture. doi:10.1016/j.clinph.2008.07.198
201. Intraoperative motor-evoked potentials and pyramidal tractography for insular gliomas—G. Neuloh 1, M. Nelles 2, H. Urbach 2, J. Schramm 1 (1 Universität Bonn, Neurochirurgische Klinik, Bonn, Germany, 2 Universität Bonn, Radiologische Klinik, Bonn, Germany) Objective: This prospective study examines the ability of intraoperative motor-evoked potentials (MEPs) to reflect ischemic involvement of the pyramidal tract, which is frequently observed with new paresis after insular glioma surgery. Methods: In a series of 45 insular gliomas, intraoperative MEP results were correlated with motor outcome and perioperative MR imaging including pyramidal tractography, FLAIR and diffusionweighted studies. Results: MEP deterioration indicated new paresis in 13 patients, and was reversible with only transient new deficit in 9 of these cases. The grade of MEP attenuation matched the clinical outcome and the morphological substrates of ischemic pyramidal tract involvement from mild edema to definite stroke. Conclusions: Intraoperative MEPs indicate motor tract ischemia in a staged way, as revealed by perioperative pyramidal tract imaging. Early intervention may avert the progression of transitory ischemia into definite stroke. doi:10.1016/j.clinph.2008.07.199
202. Nordic walking (pole striding) and depression—C. Willemer 1, K. Krüger 2, F.C. Mooren 2, K. Völker 3, S. Knecht 1, A. Flöel 1 (1 Universitäts-Klinikum Münster, Neurologie, Münster, Germany, 2 Universität Münster, Institut für Sportwissenschaft, Gießen, Germany, 3 Universität Gießen, Institut für Sportmedizin, Münster, Germany)