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EEG technique for the study of movement control
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Abstracts of the 13th European Congress of Clinical Neurophysiology / Clinical Neurophysiology 119 (2008), S1–S131
lower limbs, without conduction velocities changes. Motor studies remained essentially normal. Studies performed 10 months later showed improvement of positive sensory symptoms, but sensory nerve conduction abnormalities persisted, with only light changes. Conclusions: Sensory axonal neuropathy is seen in all our patients treated with oxaliplatin at full dose and persist for a long time after the end of chemotherapy. Follow-up neurophysiological tests are essential to diagnosis and make evident no significative changes in sensory parameters
THO41 The clinical and electrophysiological characteristics of n-hexane neuropathy in shoe makers Ilknur Aydin Canturk, Nihal Isik, Evin Akyuz, Adile Ozkan, Fatma Candan, Nuket Yildiz Istanbul Goztepe Research and Training Hospital, Neurology Department, Turkey Chronic inhalation of glues containing n-hexanes induces sensory-motor polyneuropathy. N-hexane neuropathy has also been described as case reports at the shoe industry workers be cause of its common use in the production of footwear. In this study we aimed to describe the clinical and electrophysiological characteristics of the patients who had been followed up from our polyclinic between 2000-2005, as shoe makers working in the shoe industry. According to this purpose, 26 patients have been included in the study. Neurological examination and electrophysiological studies as nerve conduction study were applied to all of the patients. 21 of the 26 patients were man (80%). The mean age of the patients was 34.5. The most common neurological symptoms were numbness in distal upper and lower extremities (90%) and distally localized muscle weakness (70%). 10 patients (39%) showed normal electrophysiological findings while 16 (61%) had electrophysiologically neuropathic findings. The main changes in the nerve conduction study were reduced amplitude of the sensory action potentials, followed by reduced amplitude of motor action potentials, reduction in motor conduction velocities and increase in distal latencies. 7 of the electrophysiologically neuropathic patients (43%) had mixed sensory-motor axonal polyneuropathy while 3 (18%) of them had motor and 6 (37%) of them had sensory axonal neuropathy. The results indicate that exposure to N-hexanes in shoe industry can cause symtomatic axonal neuropathy and the most common type of the neuropathy is mixed sensory-motor type.
THO42 A novel method to identify oxaliplatin-induced neuropathy Susanna B. Park 1 , Cindy S-Y. Lin 1 , David Goldstein 2 , Arun V. Krishnan 3 , Michael Friedlander 2 , Matthew C. Kiernan 1 1 Prince of Wales Medical Research Institute, University of New South Wales; 2 Department of Medical Oncology, Prince of Wales Hospital; 3 Institute of Neurological Sciences, Prince of Wales Hospital Purpose: Oxaliplatin, a platinum-derivative chemotherapy effective against colorectal cancer, induces significant dose-limiting neurotoxicity. Neurotoxicity presents as acute sensorimotor dysfunction immediately following infusion with axonal sensory neuropathy developing at higher cumulative doses. In this study, we have utilized nerve excitability techniques during oxaliplatin treatment to explore changes in axonal membrane properties that may be involved in both acute neurotoxicity and the development of chronic neuropathy. Method: Sensory and motor nerve excitability studies were undertaken in 25 patients undergoing oxaliplatin treatment, before and within 2-3 days post-infusion. A subset of 12 patients were assessed longitudinally across treatment. Median nerve was stimulated at the wrist, recording sensory nerve action potentials (SNAP) from the 2nd digit and compound motor action potentials (CMAP) from abductor pollicis brevis. Multiple excitability
parameters were recorded including recovery cycle of excitability (RC) and threshold electrotonus (TE). Results: Immediately following infusion, oxaliplatin significantly reduced refractoriness (RF) and superexcitability (SX) in cutaneous axons (RF reduction=3.1±1.3, p<0.05; SX reduction=-1.7±0.46, p<0.05), consistent with a partial blockade of Na+ channels. Conversely, in motor axons, refractoriness was markedly increased (-11.9±3.8,p<0.001) while superexcitability was reduced (-8.1±0.82, p<.001). Review of raw traces suggested that RF increases reflected the effect of repetitive oxaliplatin-induced motor activity arising from the neuromuscular junction. Longitudinal assessment in cutaneous axons demonstrated significant progressive changes across treatment (TE p<0.05; RF p<.01; SX p≤0.001), while motor parameters did not significantly change. By the final dose, peak SNAP amplitude decreased by 45%(p≤0.005), while CMAP amplitude remained unchanged. Importantly, changes in sensory parameters occurred prior to SNAP reduction, indicating that they may be predictive of the development of neuropathy. Conclusion: Changes in cutaneous and motor axonal membrane properties correlate with clinical symptoms in oxaliplatin-induced neurotoxicity and suggest involvement of Na+ channel dysfunction. Excitability techniques may facilitate early identification of at-risk patients, prior to the development of neuropathy.
W24 EEG technique for the study of movement control Chairpersons: R. Kristeva, Germany EEG technique for the study of movement control R. Kristeva Neurological University, Clinic Freiburg i. Br., Germany Now we know that there is synchronization between cortical motor areas and muscles but it was only in 1995 when this synchronization was shown for first time. Using one channel MEG Conway et al. (1995) have recorded the cortical activity over the contralateral motor cortex and the EMG during maintained motor contraction and applying coherence analysis have shown the synchronization between MEG and EMG in beta-frequency. For the last 12 years the beta-range CMC during steady-state motor tasks has been investigated on a large scale and it was shown that it is task-dependent, that it reflects attention, training, task compliance, displacement, and adjustment of length-tension ratio. However, the functional significance of the betarange coherence remained unclear. Therefore, we hypothesized that if the beta-range CMC has a functional role it should correlate with the behavioral performance (the error between target force and exerted force). In Kristeva et al. (2006) we showed that there is in fact such a correlation. This suggested that beta-range cortical motor CMC may promote effective corticospinal interaction during steady-state motor tasks. But how the motor cortex and the muscle are synchronized during isometric compensation for periodically modulated dynamic force? We investigated this question and showed that the cortico-muscular network oscillates at gamma frequencies during predictable dynamic force tasks to yield the rapid integration of visual and somatosensory information (Omlor et al., 2006). The absence of gamma-range coherence in a deafferented subject indicates that the contribution of proprioception in this integration is of particular importance for the generation of corticospinal gamma oscillations (Patino et al., in press). Supported by DFG grant Kr 1392/5.
THO43 Movement preparation and cortical processing of afferent inputs in cortical tremor: an event-related (de)synchronization (ERD/S) study Elise Houdayer 1 , Adrian Degardin 3 , Julia Salleron 2 , Jean-Louis Bourriez 1 , Luc Defebvre 3 , François Cassim 1 , Philippe Derambure 1 1 Departement de Neurophysiologie Clinique, CHRU de Lille, France; 2 CERIM, Unité de Biostatistiques, Université de Lille 2, France; 3 Departement de Neurologie A, CHRU de Lille, France Purpose: Cortical tremor corresponds to involuntary movements provoked
Abstracts of the 13th European Congress of Clinical Neurophysiology / Clinical Neurophysiology 119 (2008), S1–S131
lower limbs, without conduction velocities changes. Motor studies remained essentially normal. Studies performed 10 months later showed improvement of positive sensory symptoms, but sensory nerve conduction abnormalities persisted, with only light changes. Conclusions: Sensory axonal neuropathy is seen in all our patients treated with oxaliplatin at full dose and persist for a long time after the end of chemotherapy. Follow-up neurophysiological tests are essential to diagnosis and make evident no significative changes in sensory parameters
THO41 The clinical and electrophysiological characteristics of n-hexane neuropathy in shoe makers Ilknur Aydin Canturk, Nihal Isik, Evin Akyuz, Adile Ozkan, Fatma Candan, Nuket Yildiz Istanbul Goztepe Research and Training Hospital, Neurology Department, Turkey Chronic inhalation of glues containing n-hexanes induces sensory-motor polyneuropathy. N-hexane neuropathy has also been described as case reports at the shoe industry workers be cause of its common use in the production of footwear. In this study we aimed to describe the clinical and electrophysiological characteristics of the patients who had been followed up from our polyclinic between 2000-2005, as shoe makers working in the shoe industry. According to this purpose, 26 patients have been included in the study. Neurological examination and electrophysiological studies as nerve conduction study were applied to all of the patients. 21 of the 26 patients were man (80%). The mean age of the patients was 34.5. The most common neurological symptoms were numbness in distal upper and lower extremities (90%) and distally localized muscle weakness (70%). 10 patients (39%) showed normal electrophysiological findings while 16 (61%) had electrophysiologically neuropathic findings. The main changes in the nerve conduction study were reduced amplitude of the sensory action potentials, followed by reduced amplitude of motor action potentials, reduction in motor conduction velocities and increase in distal latencies. 7 of the electrophysiologically neuropathic patients (43%) had mixed sensory-motor axonal polyneuropathy while 3 (18%) of them had motor and 6 (37%) of them had sensory axonal neuropathy. The results indicate that exposure to N-hexanes in shoe industry can cause symtomatic axonal neuropathy and the most common type of the neuropathy is mixed sensory-motor type.
THO42 A novel method to identify oxaliplatin-induced neuropathy Susanna B. Park 1 , Cindy S-Y. Lin 1 , David Goldstein 2 , Arun V. Krishnan 3 , Michael Friedlander 2 , Matthew C. Kiernan 1 1 Prince of Wales Medical Research Institute, University of New South Wales; 2 Department of Medical Oncology, Prince of Wales Hospital; 3 Institute of Neurological Sciences, Prince of Wales Hospital Purpose: Oxaliplatin, a platinum-derivative chemotherapy effective against colorectal cancer, induces significant dose-limiting neurotoxicity. Neurotoxicity presents as acute sensorimotor dysfunction immediately following infusion with axonal sensory neuropathy developing at higher cumulative doses. In this study, we have utilized nerve excitability techniques during oxaliplatin treatment to explore changes in axonal membrane properties that may be involved in both acute neurotoxicity and the development of chronic neuropathy. Method: Sensory and motor nerve excitability studies were undertaken in 25 patients undergoing oxaliplatin treatment, before and within 2-3 days post-infusion. A subset of 12 patients were assessed longitudinally across treatment. Median nerve was stimulated at the wrist, recording sensory nerve action potentials (SNAP) from the 2nd digit and compound motor action potentials (CMAP) from abductor pollicis brevis. Multiple excitability
parameters were recorded including recovery cycle of excitability (RC) and threshold electrotonus (TE). Results: Immediately following infusion, oxaliplatin significantly reduced refractoriness (RF) and superexcitability (SX) in cutaneous axons (RF reduction=3.1±1.3, p<0.05; SX reduction=-1.7±0.46, p<0.05), consistent with a partial blockade of Na+ channels. Conversely, in motor axons, refractoriness was markedly increased (-11.9±3.8,p<0.001) while superexcitability was reduced (-8.1±0.82, p<.001). Review of raw traces suggested that RF increases reflected the effect of repetitive oxaliplatin-induced motor activity arising from the neuromuscular junction. Longitudinal assessment in cutaneous axons demonstrated significant progressive changes across treatment (TE p<0.05; RF p<.01; SX p≤0.001), while motor parameters did not significantly change. By the final dose, peak SNAP amplitude decreased by 45%(p≤0.005), while CMAP amplitude remained unchanged. Importantly, changes in sensory parameters occurred prior to SNAP reduction, indicating that they may be predictive of the development of neuropathy. Conclusion: Changes in cutaneous and motor axonal membrane properties correlate with clinical symptoms in oxaliplatin-induced neurotoxicity and suggest involvement of Na+ channel dysfunction. Excitability techniques may facilitate early identification of at-risk patients, prior to the development of neuropathy.
W24 EEG technique for the study of movement control Chairpersons: R. Kristeva, Germany EEG technique for the study of movement control R. Kristeva Neurological University, Clinic Freiburg i. Br., Germany Now we know that there is synchronization between cortical motor areas and muscles but it was only in 1995 when this synchronization was shown for first time. Using one channel MEG Conway et al. (1995) have recorded the cortical activity over the contralateral motor cortex and the EMG during maintained motor contraction and applying coherence analysis have shown the synchronization between MEG and EMG in beta-frequency. For the last 12 years the beta-range CMC during steady-state motor tasks has been investigated on a large scale and it was shown that it is task-dependent, that it reflects attention, training, task compliance, displacement, and adjustment of length-tension ratio. However, the functional significance of the betarange coherence remained unclear. Therefore, we hypothesized that if the beta-range CMC has a functional role it should correlate with the behavioral performance (the error between target force and exerted force). In Kristeva et al. (2006) we showed that there is in fact such a correlation. This suggested that beta-range cortical motor CMC may promote effective corticospinal interaction during steady-state motor tasks. But how the motor cortex and the muscle are synchronized during isometric compensation for periodically modulated dynamic force? We investigated this question and showed that the cortico-muscular network oscillates at gamma frequencies during predictable dynamic force tasks to yield the rapid integration of visual and somatosensory information (Omlor et al., 2006). The absence of gamma-range coherence in a deafferented subject indicates that the contribution of proprioception in this integration is of particular importance for the generation of corticospinal gamma oscillations (Patino et al., in press). Supported by DFG grant Kr 1392/5.
THO43 Movement preparation and cortical processing of afferent inputs in cortical tremor: an event-related (de)synchronization (ERD/S) study Elise Houdayer 1 , Adrian Degardin 3 , Julia Salleron 2 , Jean-Louis Bourriez 1 , Luc Defebvre 3 , François Cassim 1 , Philippe Derambure 1 1 Departement de Neurophysiologie Clinique, CHRU de Lille, France; 2 CERIM, Unité de Biostatistiques, Université de Lille 2, France; 3 Departement de Neurologie A, CHRU de Lille, France Purpose: Cortical tremor corresponds to involuntary movements provoked