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EP 62. Motor evoked potentials mapping improves detection of capsular side effects during deep brain stimulation
Abstracts / Clinical Neurophysiology 127 (2016) e168–e209
neuronal activity recording in freely behaving small animals. This device, which has a size and weight compatible for use in freely moving rats, can be clipped on the animal’s head to a previously implanted electrode. This easy ‘‘removal” property is crucial because it enables removing or even switching the stimulator/recorder during the experiments without having to anaesthetize or to operate the animal, thus minimizing stress. The device takes extracellular recorded signals from implanted electrodes, amplifies the signals with a programmable gain main amplifier by a factor of 200 to 12800 and transmits the output by radio frequency to a transceiver up to 4 m distance. Comparable to tethered recording systems, our device is working without connection cables, and has a weight of 3.9 g (without accumulator). Stimulation electronics consists essentially of two assemblies: constant-current source and power supply. The power supply of the constant current (20–200 lA) source is biphasic, so that a voltage of 6 V is required. This allows effective stimulation and recording of neuronal signals in freely behaving animals. The present study describes the validation and in vivo implementation of this device. Our testing showed that recorded neuronal activities and stimulation of the rat inferior colliculus yields similar results as previously shown by conventional wired devices. Furthermore, the bidirectional wireless device does not restrict the animal’s mobility providing a flexible method to control stimulation and neural recording under circumstances where other approaches would be difficult or impossible. Financial support: AIF. Grant No.: KF2780403JL3. doi:10.1016/j.clinph.2016.05.249
EP 62. Motor evoked potentials mapping improves detection of capsular side effects during deep brain stimulation— Y. Parpaley a,*, M. Machado Lemos Rodrigues a, L. Schönlau b, S. Skodda b (a Universitätsklinik Knappschaftskrankenhaus Bochum, Dept. of Neurosurgery, Bochum, Gambia, b Universitätsklinik Knappschaftskrankenhaus Bochum, Dept. of Neurology, Bochum, Germany) ⇑
Corresponding author.
Introduction: One of the main reasons to perform deep brain stimulation (DBS) on awake patient is detection of activation of descending capsular motor pathways as they represent therapy-limiting side effect. Current technique of capsular activation detection is based on visual detection of muscular contraction during stimulation with standard ‘‘tonic” DBS stimulation parameters. Intraoperative mapping of subcortical motor evoked potentials (MEP) during DBS surgery, as already shown in the literature, is feasible and timeefficient, also in patients under general anesthesia. We investigate value of motor evoked potentials mapping in basal ganglia as alternative measurement of safe therapeutic window in stimulation parameters. Methods: This study includes recording data of 7 Patients, undergoing awake DBS surgery in subthalamic nucleus or in thalamus and of 1 DBS patient under general anesthesia. Recording data of 16 trajectories and 32 stimulation sites was available. Anodal stimulation was applied in stereotactic target on the macroelectrode tip (microTargeting electrodes, FHC, USA) using train-of-five technique in 1 mA steps 0–5 mA. Recordings were obtained using skin surface electrodes on projection of m. mentalis, m. abductor pollicis brevis, m. flexor digitorum, m. tibialis anterior on contralateral to stimulation side. Visual detection of motor contraction under 130 Hz 60 ls stimulation in 1 mA steps (0–5 mA) was used as standard control parameter.
e201
Results: MEP recordings were successful in all stimulation sites. MEP threshold current correlated with current values of 130 Hz stimulation, which caused visually detectable muscle contractions and with postoperative DBS side effect thresholds. Detection of muscle response activation was very sensitive and muscle-specific and remained stable under repeated stimulation. Patients described very little or no discomfort during MEP mapping, significantly lower comparing to classical 130 Hz stimulation on motor-threshold. MEP threshold detection was easily obtainable under propofolremifentanyl general anesthesia and had same current values as ‘‘tonic” stimulation postoperatively. Conclusions: MEP mapping in basal ganglia is safe and feasible alternative to standard motor side-effect detection, which can improve safety and comfort of DBS procedure. MEP motor threshold correlates well to capsular activation with standard DBS parameters and can be obtained under general anesthesia. doi:10.1016/j.clinph.2016.05.250
EP 63. Spectral analysis and visualization of multi-unit activity in subthalamic nucleus in Parkinson’s as a tool for automated electrophysiological classification of basal ganglia structures during deep brain stimulation procedures—M. Machado Lemos Rodrigues a,*, S. Skodda b, Y. Parpaley a, R. Hilker-Roggendorf c (a Universitätsklinikum Knappschaftskrankenhaus Bochum, Ruhr University Bochum, Dpt. of Neurosurgery, Bochum, Germany, b Universitätsklinikum Knappschaftskrankenhaus Bochum, Ruhr University, Dpt. of Neurology, Bochum, Germany, c Klinikum Vest, Dept. of Neurology, Recklinghausen/Marl, Germany) ⇑
Corresponding author.
Introduction: In deep brain stimulation (DBS) of the subthalamic nucleus (STN) intraoperative microelectrode recordings (MER) are a well-established method for electrophysiological stereotactic target identification. Despite the main electrophysiological properties of STN are already well described (Cagnan et al., 2011, Seifried et al., 2012), mapping of STN rely on visual and acoustic inspection of raw recordings of MER trajectories. In this study we analyzed spectral decomposition and spike train patterns retrospectively of MER in STN-DBS to proposing a simple and reliable electrophysiological classification system. Secondly we suggest visualization techniques to present electrophysiological results in a user-friendly way. Patients and methods: We analyzed MER in 7 patients with bilateral STN-DBS including 26 MER trajectories retrospectively. All recordings were carried out on multiple trajectories 10 mm prior and 4–5 mm below MR-tomographic STN target along planed DBS lead trajectory. Data was recorded intraoperative by Medtronic Leadpoint system using sharp microTargeting electrodes (FHC, USA). Offline Multi-Unit activity analysis was realized with Fieldtrip-Toolbox and Matlab, Mathworks. Statistical analysis of power spectral density, noise level and spike interstimulus interval were obtained through non-parametric student’s t-test. In purpose of visualization we integrated the stereotactic surgical plan to the electrophysiological results. Results: Spectral density analysis showed a strong increase in frequency bands of 300–1000 Hz within STN borders. Spike train patterns within STN were heterogeneously and differed in firing rate and interstimulus interval to the key anatomical structures, thalamus and substantia nigra. Conclusion: Through combination of spectral density analysis and spike train analysis we propose a simple and reliable MER signal
neuronal activity recording in freely behaving small animals. This device, which has a size and weight compatible for use in freely moving rats, can be clipped on the animal’s head to a previously implanted electrode. This easy ‘‘removal” property is crucial because it enables removing or even switching the stimulator/recorder during the experiments without having to anaesthetize or to operate the animal, thus minimizing stress. The device takes extracellular recorded signals from implanted electrodes, amplifies the signals with a programmable gain main amplifier by a factor of 200 to 12800 and transmits the output by radio frequency to a transceiver up to 4 m distance. Comparable to tethered recording systems, our device is working without connection cables, and has a weight of 3.9 g (without accumulator). Stimulation electronics consists essentially of two assemblies: constant-current source and power supply. The power supply of the constant current (20–200 lA) source is biphasic, so that a voltage of 6 V is required. This allows effective stimulation and recording of neuronal signals in freely behaving animals. The present study describes the validation and in vivo implementation of this device. Our testing showed that recorded neuronal activities and stimulation of the rat inferior colliculus yields similar results as previously shown by conventional wired devices. Furthermore, the bidirectional wireless device does not restrict the animal’s mobility providing a flexible method to control stimulation and neural recording under circumstances where other approaches would be difficult or impossible. Financial support: AIF. Grant No.: KF2780403JL3. doi:10.1016/j.clinph.2016.05.249
EP 62. Motor evoked potentials mapping improves detection of capsular side effects during deep brain stimulation— Y. Parpaley a,*, M. Machado Lemos Rodrigues a, L. Schönlau b, S. Skodda b (a Universitätsklinik Knappschaftskrankenhaus Bochum, Dept. of Neurosurgery, Bochum, Gambia, b Universitätsklinik Knappschaftskrankenhaus Bochum, Dept. of Neurology, Bochum, Germany) ⇑
Corresponding author.
Introduction: One of the main reasons to perform deep brain stimulation (DBS) on awake patient is detection of activation of descending capsular motor pathways as they represent therapy-limiting side effect. Current technique of capsular activation detection is based on visual detection of muscular contraction during stimulation with standard ‘‘tonic” DBS stimulation parameters. Intraoperative mapping of subcortical motor evoked potentials (MEP) during DBS surgery, as already shown in the literature, is feasible and timeefficient, also in patients under general anesthesia. We investigate value of motor evoked potentials mapping in basal ganglia as alternative measurement of safe therapeutic window in stimulation parameters. Methods: This study includes recording data of 7 Patients, undergoing awake DBS surgery in subthalamic nucleus or in thalamus and of 1 DBS patient under general anesthesia. Recording data of 16 trajectories and 32 stimulation sites was available. Anodal stimulation was applied in stereotactic target on the macroelectrode tip (microTargeting electrodes, FHC, USA) using train-of-five technique in 1 mA steps 0–5 mA. Recordings were obtained using skin surface electrodes on projection of m. mentalis, m. abductor pollicis brevis, m. flexor digitorum, m. tibialis anterior on contralateral to stimulation side. Visual detection of motor contraction under 130 Hz 60 ls stimulation in 1 mA steps (0–5 mA) was used as standard control parameter.
e201
Results: MEP recordings were successful in all stimulation sites. MEP threshold current correlated with current values of 130 Hz stimulation, which caused visually detectable muscle contractions and with postoperative DBS side effect thresholds. Detection of muscle response activation was very sensitive and muscle-specific and remained stable under repeated stimulation. Patients described very little or no discomfort during MEP mapping, significantly lower comparing to classical 130 Hz stimulation on motor-threshold. MEP threshold detection was easily obtainable under propofolremifentanyl general anesthesia and had same current values as ‘‘tonic” stimulation postoperatively. Conclusions: MEP mapping in basal ganglia is safe and feasible alternative to standard motor side-effect detection, which can improve safety and comfort of DBS procedure. MEP motor threshold correlates well to capsular activation with standard DBS parameters and can be obtained under general anesthesia. doi:10.1016/j.clinph.2016.05.250
EP 63. Spectral analysis and visualization of multi-unit activity in subthalamic nucleus in Parkinson’s as a tool for automated electrophysiological classification of basal ganglia structures during deep brain stimulation procedures—M. Machado Lemos Rodrigues a,*, S. Skodda b, Y. Parpaley a, R. Hilker-Roggendorf c (a Universitätsklinikum Knappschaftskrankenhaus Bochum, Ruhr University Bochum, Dpt. of Neurosurgery, Bochum, Germany, b Universitätsklinikum Knappschaftskrankenhaus Bochum, Ruhr University, Dpt. of Neurology, Bochum, Germany, c Klinikum Vest, Dept. of Neurology, Recklinghausen/Marl, Germany) ⇑
Corresponding author.
Introduction: In deep brain stimulation (DBS) of the subthalamic nucleus (STN) intraoperative microelectrode recordings (MER) are a well-established method for electrophysiological stereotactic target identification. Despite the main electrophysiological properties of STN are already well described (Cagnan et al., 2011, Seifried et al., 2012), mapping of STN rely on visual and acoustic inspection of raw recordings of MER trajectories. In this study we analyzed spectral decomposition and spike train patterns retrospectively of MER in STN-DBS to proposing a simple and reliable electrophysiological classification system. Secondly we suggest visualization techniques to present electrophysiological results in a user-friendly way. Patients and methods: We analyzed MER in 7 patients with bilateral STN-DBS including 26 MER trajectories retrospectively. All recordings were carried out on multiple trajectories 10 mm prior and 4–5 mm below MR-tomographic STN target along planed DBS lead trajectory. Data was recorded intraoperative by Medtronic Leadpoint system using sharp microTargeting electrodes (FHC, USA). Offline Multi-Unit activity analysis was realized with Fieldtrip-Toolbox and Matlab, Mathworks. Statistical analysis of power spectral density, noise level and spike interstimulus interval were obtained through non-parametric student’s t-test. In purpose of visualization we integrated the stereotactic surgical plan to the electrophysiological results. Results: Spectral density analysis showed a strong increase in frequency bands of 300–1000 Hz within STN borders. Spike train patterns within STN were heterogeneously and differed in firing rate and interstimulus interval to the key anatomical structures, thalamus and substantia nigra. Conclusion: Through combination of spectral density analysis and spike train analysis we propose a simple and reliable MER signal