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O203 Neuromodulation of lower limb motor circuitry with transcutaneous lumbar spinal cord direct current stimulation
Abstracts / Clinical Neurophysiology 128 (2017) e178–e303
O202 Combining the strengths of passive functional mapping and electrical cortical stimulation—Robert Prueckl 1, Christopher Kapeller 1, Johannes Gruenwald 1, Christoph Guger 1, Francisco Fernandes 2, Martin Walchshofer 2, Alexander Heilinger 2,*, Hiroshi Ogawa 3, Kyousuke Kamada 3, Milena Korostenskaja 4 (1 Guger Technologies OG, Research & Development, Schiedlberg, Austria, 2 G.tec medical engineering GmbH, Research & Development, Schiedlberg, Austria, 3 Asahikawa Medical University, Neurosurgery, Asahikawa, Japan, 4 Florida Hospital for Children, Neurosurgery, Orlando, USA) Background: The identification of eloquent cortex, surrounding the seizure onset zone, is important for predictable surgical outcome in epilepsy patients. The symptoms during electrical cortical stimulation (ECS) lead to a functional map that includes motor, sensory, and other functions. In this study we test whether a prevenient high-gamma mapping (HGM) with electrocorticography can guide ECS mapping and therefore optimizes it in terms of time and stimulation related risks. Methods: Four patients underwent clinical ECS mapping and volunteered for an HGM session. The results enable an evaluation of the potential HGM contribution to the effectiveness of the ECS protocol. During HGM sessions, all patients performed hand movement, tongue movement, and listened to words. As a measure, the significance of guidance derives from a bootstrapping approach and indicates whether the HGM-guided ECS outperforms a random guidance. Additionally the potential reduction of required stimulations was calculated. Results: On average, 52 electrode pairs were stimulated, where on average 18.8 electrodes relate to motor, sensory, or language-related functions. The number of required ECS stimulations could have been reduced to 31.3 electrodes on average (60.2%). Even with the reduced number of stimulations, all the electrodes that have originally been revealed, were identified. The HGM mapping significantly improves the ECS protocol for all four subjects (p < 0.05). Conclusions: Compared to pure ECS, the proposed combined approach greatly reduces the required overall mapping time/effort as the HGM initially highlights the potential stimulation targets. We are encouraged that the presented system improves functional mapping in clinical practice. Keywords: Neurosurgery, ECS, Functional mapping, Brain stimulation, Epilepsy, Brain tumour, ECoG doi:10.1016/j.clinph.2017.07.210
O203 Neuromodulation of lower limb motor circuitry with transcutaneous lumbar spinal cord direct current stimulation— Mamede De Carvalho 1, Mariana Pereira 1, Sofia Fernandes 2, Pedro Cavaleiro Miranda 2 (1 Institute of Physiology, Faculty of Medicine, University of Lisbon, Instituto de Medicina Molecular, Lisboa, Portugal, 2 Faculdade de Ciências, Universidade de Lisboa, Instituto de Biofísica e Engenharia Biomédica, Lisboa, Portugal) Objectives: The advent of transcranial direct current stimulation (tDCS) introduced growing interest in modulating spinal circuits, altered in many neurologic conditions. Transcutaneous spinal direct current stimulation (tsDCS) of cervical and thoracic spine regions was observed to modulate sensory and motor responses. Combining clinical studies with computational modelling can be a powerful tool to establish tsDCS protocols for specific therapeutic purposes. The aim of this study was to measure the effects of
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tsDCS delivered on the lumbar region on motor spinal responses and observe if these were consistent with the electric field (E-field) distribution predicted in the spinal cord using a computational model. Methods: The exploratory study design was double-blind crossover pseudo-randomized. tsDCS was delivered for 15 min (anodal, cathodal, sham) at L2 vertebra level (2.5 mA, 90 C/cm2) in 15 healthy subjects. The F-wave, H-reflex, cortical silent period, motor evoked potential and sympathetic skin response were analysed. Statistical methods were applied with Bonferroni correction for multiple comparisons (p = 0.05). A human volume conductor model was obtained from available databases. E-field distributions in the spinal grey matter (GM) and white matter (WM) were calculated considering the same protocol and tissue conductivities based on literature review. Results: We observed the increase of the F-wave mean latency, however this was independent of the type of intervention. No other differences were observed (p > 0.05, Bonferroni corrected). The Efield magnitude predicted for the lumbosacral spinal GM and WM was <0.15 V/m. During tDCS, the E-field in the motor cortex is >0.15 V/m in protocols with observed modulation of motor responses. Discussion: Therefore, the E-field obtained is not sufficient to ensure neuromodulation, which is consistent with the absence of effects observed. The tsDCS protocol applied did not change motor response to delivered stimulus, having no effect on lumbosacral motor circuits. Conclusions: Future studies should address diversified protocols sustained in computational models. Significance: Computer models of E-field for tsDCS should be optimized to increase chances of a biological effect. Keywords: tsDCS, Spinal cord, Modulation, Neurophysiology, Computational modelling doi:10.1016/j.clinph.2017.07.211
O204 Simultaneous bi-hemispheric repetitive transcranial magnetic stimulation for upper limb motor recovery in chronic stroke: A double blind placebo controlled study—Raffaella Chieffo 1, Giuseppe Scopelliti 1, Mario Fichera 1, Giovanni Di Maggio 1, Roberto Santangelo 1, Simone Guerrieri 1, Elise Houdayer 1, Abraham Zangen 2, Giancarlo Comi 1, Letizia Leocani 1 (1 Hospital San Raffaele, Department of Neurology, Milan, Italy, 2 Ben-Gurion University, Department of Life Sciences, Beer-Sheva, Israel) Objective: repetitive transcranial magnetic stimulation (rTMS) is a promising intervention for the treatment of post-stroke motor deficits. Since the crucial role of non-primary motor cortices and contralesional brain areas is emerging for motor recovery in chronic stroke; we assessed safety and efficacy of bilateral rTMS over the motor areas associated to physical training (PT) on upper extremity (UE) motor function. Methods: double-blind, placebo-controlled trial on 20 patients with chronic stroke conditioning moderate to mild upper limb motor impairment. Eleven sessions of high frequency rTMS were delivered with the H-coil over the motor areas bilaterally. Subjects were randomly allocated to the real rTMS plus PT or the placebo (sham) rTMS plus PT. UE impairment was evaluated by the Fugl-Meyer assessment for UE (FM-UE), Modified Ashworth Scale (MAS) and hand grip strength at baseline (T0), after treatment (T1) and onemonth follow-up (T2).
O202 Combining the strengths of passive functional mapping and electrical cortical stimulation—Robert Prueckl 1, Christopher Kapeller 1, Johannes Gruenwald 1, Christoph Guger 1, Francisco Fernandes 2, Martin Walchshofer 2, Alexander Heilinger 2,*, Hiroshi Ogawa 3, Kyousuke Kamada 3, Milena Korostenskaja 4 (1 Guger Technologies OG, Research & Development, Schiedlberg, Austria, 2 G.tec medical engineering GmbH, Research & Development, Schiedlberg, Austria, 3 Asahikawa Medical University, Neurosurgery, Asahikawa, Japan, 4 Florida Hospital for Children, Neurosurgery, Orlando, USA) Background: The identification of eloquent cortex, surrounding the seizure onset zone, is important for predictable surgical outcome in epilepsy patients. The symptoms during electrical cortical stimulation (ECS) lead to a functional map that includes motor, sensory, and other functions. In this study we test whether a prevenient high-gamma mapping (HGM) with electrocorticography can guide ECS mapping and therefore optimizes it in terms of time and stimulation related risks. Methods: Four patients underwent clinical ECS mapping and volunteered for an HGM session. The results enable an evaluation of the potential HGM contribution to the effectiveness of the ECS protocol. During HGM sessions, all patients performed hand movement, tongue movement, and listened to words. As a measure, the significance of guidance derives from a bootstrapping approach and indicates whether the HGM-guided ECS outperforms a random guidance. Additionally the potential reduction of required stimulations was calculated. Results: On average, 52 electrode pairs were stimulated, where on average 18.8 electrodes relate to motor, sensory, or language-related functions. The number of required ECS stimulations could have been reduced to 31.3 electrodes on average (60.2%). Even with the reduced number of stimulations, all the electrodes that have originally been revealed, were identified. The HGM mapping significantly improves the ECS protocol for all four subjects (p < 0.05). Conclusions: Compared to pure ECS, the proposed combined approach greatly reduces the required overall mapping time/effort as the HGM initially highlights the potential stimulation targets. We are encouraged that the presented system improves functional mapping in clinical practice. Keywords: Neurosurgery, ECS, Functional mapping, Brain stimulation, Epilepsy, Brain tumour, ECoG doi:10.1016/j.clinph.2017.07.210
O203 Neuromodulation of lower limb motor circuitry with transcutaneous lumbar spinal cord direct current stimulation— Mamede De Carvalho 1, Mariana Pereira 1, Sofia Fernandes 2, Pedro Cavaleiro Miranda 2 (1 Institute of Physiology, Faculty of Medicine, University of Lisbon, Instituto de Medicina Molecular, Lisboa, Portugal, 2 Faculdade de Ciências, Universidade de Lisboa, Instituto de Biofísica e Engenharia Biomédica, Lisboa, Portugal) Objectives: The advent of transcranial direct current stimulation (tDCS) introduced growing interest in modulating spinal circuits, altered in many neurologic conditions. Transcutaneous spinal direct current stimulation (tsDCS) of cervical and thoracic spine regions was observed to modulate sensory and motor responses. Combining clinical studies with computational modelling can be a powerful tool to establish tsDCS protocols for specific therapeutic purposes. The aim of this study was to measure the effects of
e243
tsDCS delivered on the lumbar region on motor spinal responses and observe if these were consistent with the electric field (E-field) distribution predicted in the spinal cord using a computational model. Methods: The exploratory study design was double-blind crossover pseudo-randomized. tsDCS was delivered for 15 min (anodal, cathodal, sham) at L2 vertebra level (2.5 mA, 90 C/cm2) in 15 healthy subjects. The F-wave, H-reflex, cortical silent period, motor evoked potential and sympathetic skin response were analysed. Statistical methods were applied with Bonferroni correction for multiple comparisons (p = 0.05). A human volume conductor model was obtained from available databases. E-field distributions in the spinal grey matter (GM) and white matter (WM) were calculated considering the same protocol and tissue conductivities based on literature review. Results: We observed the increase of the F-wave mean latency, however this was independent of the type of intervention. No other differences were observed (p > 0.05, Bonferroni corrected). The Efield magnitude predicted for the lumbosacral spinal GM and WM was <0.15 V/m. During tDCS, the E-field in the motor cortex is >0.15 V/m in protocols with observed modulation of motor responses. Discussion: Therefore, the E-field obtained is not sufficient to ensure neuromodulation, which is consistent with the absence of effects observed. The tsDCS protocol applied did not change motor response to delivered stimulus, having no effect on lumbosacral motor circuits. Conclusions: Future studies should address diversified protocols sustained in computational models. Significance: Computer models of E-field for tsDCS should be optimized to increase chances of a biological effect. Keywords: tsDCS, Spinal cord, Modulation, Neurophysiology, Computational modelling doi:10.1016/j.clinph.2017.07.211
O204 Simultaneous bi-hemispheric repetitive transcranial magnetic stimulation for upper limb motor recovery in chronic stroke: A double blind placebo controlled study—Raffaella Chieffo 1, Giuseppe Scopelliti 1, Mario Fichera 1, Giovanni Di Maggio 1, Roberto Santangelo 1, Simone Guerrieri 1, Elise Houdayer 1, Abraham Zangen 2, Giancarlo Comi 1, Letizia Leocani 1 (1 Hospital San Raffaele, Department of Neurology, Milan, Italy, 2 Ben-Gurion University, Department of Life Sciences, Beer-Sheva, Israel) Objective: repetitive transcranial magnetic stimulation (rTMS) is a promising intervention for the treatment of post-stroke motor deficits. Since the crucial role of non-primary motor cortices and contralesional brain areas is emerging for motor recovery in chronic stroke; we assessed safety and efficacy of bilateral rTMS over the motor areas associated to physical training (PT) on upper extremity (UE) motor function. Methods: double-blind, placebo-controlled trial on 20 patients with chronic stroke conditioning moderate to mild upper limb motor impairment. Eleven sessions of high frequency rTMS were delivered with the H-coil over the motor areas bilaterally. Subjects were randomly allocated to the real rTMS plus PT or the placebo (sham) rTMS plus PT. UE impairment was evaluated by the Fugl-Meyer assessment for UE (FM-UE), Modified Ashworth Scale (MAS) and hand grip strength at baseline (T0), after treatment (T1) and onemonth follow-up (T2).