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Serrano-Amenos C, Hu F, Wang PT, Heydari P, Do AH, Nenadic Z. Simulation-Informed Power Budget Estimate of a Fully-Implantable Brain-Computer Interface. Ann Biomed Eng 2024; 52:2269-2281. [PMID: 38753110 DOI: 10.1007/s10439-024-03528-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 04/28/2024] [Indexed: 07/16/2024]
Abstract
This study aims to estimate the maximum power consumption that guarantees a thermally safe operation for a titanium-enclosed chest wall unit (CWU) subcutaneously implanted in the pre-pectoral area. This unit is a central piece of an envisioned fully-implantable bi-directional brain-computer interface (BD-BCI). To this end, we created a thermal simulation model using the finite element method implemented in COMSOL. We also performed a sensitivity analysis to ensure that our predictions were robust against the natural variation of physiological and environmental parameters. Based on this analysis, we predict that the CWU can consume between 378 and 538 mW of power without raising the surrounding tissue's temperature above the thermal safety threshold of 2 ∘ C. This power budget should be sufficient to power all of the CWU's basic functionalities, which include training the decoder, online decoding, wireless data transmission, and cortical stimulation. This power budget assessment provides an important specification for the design of a CWU-an integral part of a fully-implantable BD-BCI system.
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Affiliation(s)
| | - Frank Hu
- Department of Mechanical and Aerospace Engineering, UCI, Irvine, CA, 92697, USA
| | - Po T Wang
- Department of Biomedical Engineering, UCI, Irvine, CA, 92697, USA
| | - Payam Heydari
- Department of Electrical Engineering and Computer Science, UCI, Irvine, CA, 92697, USA
| | - An H Do
- Department of Neurology, UCI, Irvine, CA, 92697, USA
| | - Zoran Nenadic
- Department of Biomedical Engineering, UCI, Irvine, CA, 92697, USA
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Woods JE, Singer AL, Alrashdan F, Tan W, Tan C, Sheth SA, Sheth SA, Robinson JT. Miniature battery-free epidural cortical stimulators. SCIENCE ADVANCES 2024; 10:eadn0858. [PMID: 38608028 PMCID: PMC11014439 DOI: 10.1126/sciadv.adn0858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 03/11/2024] [Indexed: 04/14/2024]
Abstract
Miniaturized neuromodulation systems could improve the safety and reduce the invasiveness of bioelectronic neuromodulation. However, as implantable bioelectronic devices are made smaller, it becomes difficult to store enough power for long-term operation in batteries. Here, we present a battery-free epidural cortical stimulator that is only 9 millimeters in width yet can safely receive enough wireless power using magnetoelectric antennas to deliver 14.5-volt stimulation bursts, which enables it to stimulate cortical activity on-demand through the dura. The device has digitally programmable stimulation output and centimeter-scale alignment tolerances when powered by an external transmitter. We demonstrate that this device has enough power and reliability for real-world operation by showing acute motor cortex activation in human patients and reliable chronic motor cortex activation for 30 days in a porcine model. This platform opens the possibility of simple surgical procedures for precise neuromodulation.
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Affiliation(s)
- Joshua E. Woods
- Department of Electrical and Computer Engineering, Rice University, 6100 Main St, Houston, TX 77005, USA
| | - Amanda L. Singer
- Motif Neurotech, 2450 Holcombe Blvd, Houston, TX 77021, USA
- Applied Physics Program, Rice University, 6100 Main St, Houston, TX 77005, USA
| | - Fatima Alrashdan
- Department of Electrical and Computer Engineering, Rice University, 6100 Main St, Houston, TX 77005, USA
| | - Wendy Tan
- Department of Electrical and Computer Engineering, Rice University, 6100 Main St, Houston, TX 77005, USA
| | - Chunfeng Tan
- Department of Neurology, UTHealth McGovern Medical School, 6431 Fannin St, Houston, TX 77030, USA
| | - Sunil A. Sheth
- Department of Neurology, UTHealth McGovern Medical School, 6431 Fannin St, Houston, TX 77030, USA
| | - Sameer A. Sheth
- Department of Neurosurgery, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA
| | - Jacob T. Robinson
- Department of Electrical and Computer Engineering, Rice University, 6100 Main St, Houston, TX 77005, USA
- Motif Neurotech, 2450 Holcombe Blvd, Houston, TX 77021, USA
- Applied Physics Program, Rice University, 6100 Main St, Houston, TX 77005, USA
- Department of Bioengineering, Rice University, 6100 Main St, Houston, TX 77005, USA
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA
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3
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Wong JK, Lopes JMLJ, Hu W, Wang A, Au KLK, Stiep T, Frey J, Toledo JB, Raike RS, Okun MS, Almeida L. Double blind, nonrandomized crossover study of active recharge biphasic deep brain stimulation for primary dystonia. Parkinsonism Relat Disord 2023; 109:105328. [PMID: 36827951 DOI: 10.1016/j.parkreldis.2023.105328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/12/2023] [Accepted: 02/13/2023] [Indexed: 02/19/2023]
Abstract
BACKGROUND Deep brain stimulation (DBS) of the globus pallidus interna (GPi) is an effective therapy for select patients with primary dystonia. DBS programming for dystonia is often challenging due to variable time to symptomatic improvement or stimulation induced side effects (SISE) such as capsular or optic tract activation which can prolong device optimization. OBJECTIVE To characterize the safety and tolerability of active recharge biphasic DBS (bDBS) in primary dystonia and to compare it to conventional clinical DBS (clinDBS). METHODS Ten subjects with primary dystonia and GPi DBS underwent a single center, double blind, nonrandomized crossover study comparing clinDBS versus bDBS. The testing occurred over two-days. bDBS and clinDBS were administered on separate days and each was activated for 6 h. Rating scales were collected by video recording and scored by four blinded movement disorders trained neurologists. RESULTS The bDBS paradigm was safe and well-tolerated in all ten subjects. There were no persistent SISE reported. The mean change in the Unified Dystonia Rating Scale after 4 h of stimulation was greater in bDBS when compared to clinDBS (-6.5 vs 0.3, p < 0.04). CONCLUSION In this pilot study, we demonstrated that biphasic DBS is a novel stimulation paradigm which can be administered safely. The biphasic waveform revealed a greater immediate improvement. Further studies are needed to determine whether this immediate improvement persists with chronic stimulation or if clinDBS will eventually achieve similar levels of improvement to bDBS over time.
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Affiliation(s)
- Joshua K Wong
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States.
| | - Janine Melo Lobo Jofili Lopes
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
| | - Wei Hu
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
| | - Anson Wang
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
| | - Ka Loong Kelvin Au
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Tamara Stiep
- Department of Neurology, UCSF Weill Institute for Neurosciences, Movement Disorder and Neuromodulation Center, University of California San Francisco, CA, United States
| | - Jessica Frey
- Department of Neurology, Rockefeller Neurosciences Institute, West Virginia University, Morgantown, WV, United States
| | - Jon B Toledo
- Nantz National Alzheimer Center, Stanley H. Appel Department of Neurology, Houston Methodist Hospital, Houston, TX, United States
| | - Robert S Raike
- Restorative Therapies Group Implantables, Research and Core Technology, Medtronic Inc., Minneapolis, MN, United States
| | - Michael S Okun
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
| | - Leonardo Almeida
- Department of Neurology, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
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Baniasadi M, Petersen MV, Gonçalves J, Horn A, Vlasov V, Hertel F, Husch A. DBSegment: Fast and robust segmentation of deep brain structures considering domain generalization. Hum Brain Mapp 2023; 44:762-778. [PMID: 36250712 PMCID: PMC9842883 DOI: 10.1002/hbm.26097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/30/2022] [Accepted: 09/15/2022] [Indexed: 01/25/2023] Open
Abstract
Segmenting deep brain structures from magnetic resonance images is important for patient diagnosis, surgical planning, and research. Most current state-of-the-art solutions follow a segmentation-by-registration approach, where subject magnetic resonance imaging (MRIs) are mapped to a template with well-defined segmentations. However, registration-based pipelines are time-consuming, thus, limiting their clinical use. This paper uses deep learning to provide a one-step, robust, and efficient deep brain segmentation solution directly in the native space. The method consists of a preprocessing step to conform all MRI images to the same orientation, followed by a convolutional neural network using the nnU-Net framework. We use a total of 14 datasets from both research and clinical collections. Of these, seven were used for training and validation and seven were retained for testing. We trained the network to segment 30 deep brain structures, as well as a brain mask, using labels generated from a registration-based approach. We evaluated the generalizability of the network by performing a leave-one-dataset-out cross-validation, and independent testing on unseen datasets. Furthermore, we assessed cross-domain transportability by evaluating the results separately on different domains. We achieved an average dice score similarity of 0.89 ± 0.04 on the test datasets when compared to the registration-based gold standard. On our test system, the computation time decreased from 43 min for a reference registration-based pipeline to 1.3 min. Our proposed method is fast, robust, and generalizes with high reliability. It can be extended to the segmentation of other brain structures. It is publicly available on GitHub, and as a pip package for convenient usage.
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Affiliation(s)
- Mehri Baniasadi
- National Department of Neurosurgery, Centre Hospitalier deLuxembourg Center for Systems Biomedicine, University of LuxembourgEsch‐sur‐AlzetteLuxembourg
| | - Mikkel V. Petersen
- Department of Clinical Medicine, Center of Functionally Integrative NeuroscienceUniversity of AarhusAarhusDenmark
| | - Jorge Gonçalves
- Luxembourg Center for Systems BiomedicineUniversity of LuxembourgEsch‐sur‐AlzetteLuxembourg
| | - Andreas Horn
- Neuromodulation and Movement Disorders Unit, Department of NeurologyCharité–Universitätsmedizin BerlinBerlinGermany
- MGH Neurosurgery and Center for Neurotechnology and Neurorecovery at MGH Neurology Massachusetts General HospitalHarvard Medical SchoolBostonUSA
- Center for Brain Circuit Therapeutics, Department of Neurology, Brigham and Women's HospitalHarvard Medical SchoolBostonUSA
| | - Vanja Vlasov
- Luxembourg Center for Systems BiomedicineUniversity of LuxembourgEsch‐sur‐AlzetteLuxembourg
| | - Frank Hertel
- National Department of NeurosurgeryCentre Hospitalier de LuxembourgLuxembourg
| | - Andreas Husch
- Luxembourg Center for Systems BiomedicineUniversity of LuxembourgEsch‐sur‐AlzetteLuxembourg
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Nordenström S, Petermann K, Debove I, Nowacki A, Krack P, Pollo C, Nguyen TAK. Programming of subthalamic nucleus deep brain stimulation for Parkinson's disease with sweet spot-guided parameter suggestions. Front Hum Neurosci 2022; 16:925283. [PMID: 36393984 PMCID: PMC9663652 DOI: 10.3389/fnhum.2022.925283] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 09/30/2022] [Indexed: 10/24/2023] Open
Abstract
Deep Brain Stimulation (DBS) is an effective treatment for advanced Parkinson's disease. However, identifying stimulation parameters, such as contact and current amplitudes, is time-consuming based on trial and error. Directional leads add more stimulation options and render this process more challenging with a higher workload for neurologists and more discomfort for patients. In this study, a sweet spot-guided algorithm was developed that automatically suggested stimulation parameters. These suggestions were retrospectively compared to clinical monopolar reviews. A cohort of 24 Parkinson's disease patients underwent bilateral DBS implantation in the subthalamic nucleus at our center. First, the DBS' leads were reconstructed with the open-source toolbox Lead-DBS. Second, a sweet spot for rigidity reduction was set as the desired stimulation target for programming. This sweet spot and estimations of the volume of tissue activated were used to suggest (i) the best lead level, (ii) the best contact, and (iii) the effect thresholds for full therapeutic effect for each contact. To assess these sweet spot-guided suggestions, the clinical monopolar reviews were considered as ground truth. In addition, the sweet spot-guided suggestions for best lead level and best contact were compared against reconstruction-guided suggestions, which considered the lead location with respect to the subthalamic nucleus. Finally, a graphical user interface was developed as an add-on to Lead-DBS and is publicly available. With the interface, suggestions for all contacts of a lead can be generated in a few seconds. The accuracy for suggesting the best out of four lead levels was 56%. These sweet spot-guided suggestions were not significantly better than reconstruction-guided suggestions (p = 0.3). The accuracy for suggesting the best out of eight contacts was 41%. These sweet spot-guided suggestions were significantly better than reconstruction-guided suggestions (p < 0.001). The sweet spot-guided suggestions of each contact's effect threshold had a mean error of 1.2 mA. On an individual lead level, the suggestions can vary more with mean errors ranging from 0.3 to 4.8 mA. Further analysis is warranted to improve the sweet spot-guided suggestions and to account for more symptoms and stimulation-induced side effects.
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Affiliation(s)
- Simon Nordenström
- Department of Neurosurgery, University Hospital Bern, Bern, Switzerland
| | - Katrin Petermann
- Department of Neurology, University Hospital Bern, Bern, Switzerland
| | - Ines Debove
- Department of Neurology, University Hospital Bern, Bern, Switzerland
| | - Andreas Nowacki
- Department of Neurosurgery, University Hospital Bern, Bern, Switzerland
| | - Paul Krack
- Department of Neurology, University Hospital Bern, Bern, Switzerland
| | - Claudio Pollo
- Department of Neurosurgery, University Hospital Bern, Bern, Switzerland
| | - T. A. Khoa Nguyen
- Department of Neurosurgery, University Hospital Bern, Bern, Switzerland
- ARTORG Center for Biomedical Engineering Research, University Bern, Bern, Switzerland
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6
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Connolly MJ, Cole ER, Isbaine F, de Hemptinne C, Starr PA, Willie JT, Gross RE, Miocinovic S. Multi-objective data-driven optimization for improving deep brain stimulation in Parkinson's disease. J Neural Eng 2021; 18. [PMID: 33862604 DOI: 10.1088/1741-2552/abf8ca] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/16/2021] [Indexed: 11/12/2022]
Abstract
Objective.Deep brain stimulation (DBS) is an effective treatment for Parkinson's disease (PD) but its success depends on a time-consuming process of trial-and-error to identify the optimal stimulation settings for each individual patient. Data-driven optimization algorithms have been proposed to efficiently find the stimulation setting that maximizes a quantitative biomarker of symptom relief. However, these algorithms cannot efficiently take into account stimulation settings that may control symptoms but also cause side effects. Here we demonstrate how multi-objective data-driven optimization can be used to find the optimal trade-off between maximizing symptom relief and minimizing side effects.Approach.Cortical and motor evoked potential data collected from PD patients during intraoperative stimulation of the subthalamic nucleus were used to construct a framework for designing and prototyping data-driven multi-objective optimization algorithms. Using this framework, we explored how these techniques can be applied clinically, and characterized the design features critical for solving this optimization problem. Our two optimization objectives were to maximize cortical evoked potentials, a putative biomarker of therapeutic benefit, and to minimize motor potentials, a biomarker of motor side effects.Main Results.Using thisin silicodesign framework, we demonstrated how the optimal trade-off between two objectives can substantially reduce the stimulation parameter space by 61 ± 19%. The best algorithm for identifying the optimal trade-off between the two objectives was a Bayesian optimization approach with an area under the receiver operating characteristic curve of up to 0.94 ± 0.02, which was possible with the use of a surrogate model and a well-tuned acquisition function to efficiently select which stimulation settings to sample.Significance.These findings show that multi-objective optimization is a promising approach for identifying the optimal trade-off between symptom relief and side effects in DBS. Moreover, these approaches can be readily extended to newly discovered biomarkers, adapted to DBS for disorders beyond PD, and can scale with the development of more complex DBS devices.
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Affiliation(s)
- Mark J Connolly
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, United States of America
| | - Eric R Cole
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, United States of America
| | - Faical Isbaine
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA 30322, United States of America
| | - Coralie de Hemptinne
- Department of Neurology, University of Florida, Gainesville, FL 32608, United States of America
| | - Phillip A Starr
- Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, United States of America
| | - Jon T Willie
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO 63110, United States of America
| | - Robert E Gross
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, United States of America.,Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA 30322, United States of America.,Department of Neurology, Emory University School of Medicine, 12 Executive Park Drive North East, Atlanta, GA 30322, United States of America
| | - Svjetlana Miocinovic
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, United States of America.,Department of Neurology, Emory University School of Medicine, 12 Executive Park Drive North East, Atlanta, GA 30322, United States of America
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7
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Baniasadi M, Proverbio D, Gonçalves J, Hertel F, Husch A. FastField: An open-source toolbox for efficient approximation of deep brain stimulation electric fields. Neuroimage 2020; 223:117330. [DOI: 10.1016/j.neuroimage.2020.117330] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/26/2020] [Accepted: 08/25/2020] [Indexed: 01/25/2023] Open
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Iredale E, Deweyert A, Hoover DA, Chen JZ, Schmid S, Hebb MO, Peters TM, Wong E. Optimization of multi-electrode implant configurations and programming for the delivery of non-ablative electric fields in intratumoral modulation therapy. Med Phys 2020; 47:5441-5454. [PMID: 32978963 DOI: 10.1002/mp.14496] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 09/10/2020] [Accepted: 09/12/2020] [Indexed: 12/22/2022] Open
Abstract
PURPOSE Application of low intensity electric fields to interfere with tumor growth is being increasingly recognized as a promising new cancer treatment modality. Intratumoral modulation therapy (IMT) is a developing technology that uses multiple electrodes implanted within or adjacent tumor regions to deliver electric fields to treat cancer. In this study, the determination of optimal IMT parameters was cast as a mathematical optimization problem, and electrode configurations, programming, optimization, and maximum treatable tumor size were evaluated in the simplest and easiest to understand spherical tumor model. The establishment of electrode placement and programming rules to maximize electric field tumor coverage designed specifically for IMT is the first step in developing an effective IMT treatment planning system. METHODS Finite element method electric field computer simulations for tumor models with 2 to 7 implanted electrodes were performed to quantify the electric field over time with various parameters, including number of electrodes (2 to 7), number of contacts per electrode (1 to 3), location within tumor volume, and input waveform with relative phase shift between 0 and 2π radians. Homogeneous tissue specific conductivity and dielectric values were assigned to the spherical tumor and surrounding tissue volume. In order to achieve the goal of covering the tumor volume with a uniform threshold of 1 V/cm electric field, a custom least square objective function was used to maximize the tumor volume covered by 1 V/cm time averaged field, while maximizing the electric field in voxels receiving less than this threshold. An additional term in the objective function was investigated with a weighted tissue sparing term, to minimize the field to surrounding tissues. The positions of the electrodes were also optimized to maximize target coverage with the fewest number of electrodes. The complexity of this optimization problem including its non-convexity, the presence of many local minima, and the computational load associated with these stochastic based optimizations led to the use of a custom pattern search algorithm. Optimization parameters were bounded between 0 and 2π radians for phase shift, and anywhere within the tumor volume for location. The robustness of the pattern search method was then evaluated with 50 random initial parameter values. RESULTS The optimization algorithm was successfully implemented, and for 2 to 4 electrodes, equally spaced relative phase shifts and electrodes placed equidistant from each other was optimal. For 5 electrodes, up to 2.5 cm diameter tumors with 2.0 V, and 4.1 cm with 4.0 V could be treated with the optimal configuration of a centrally placed electrode and 4 surrounding electrodes. The use of 7 electrodes allow for 3.4 cm diameter coverage at 2.0 V and 5.5 cm at 4.0 V. The evaluation of the optimization method using 50 random initial parameter values found the method to be robust in finding the optimal solution. CONCLUSIONS This study has established a robust optimization method for temporally optimizing electric field tumor coverage for IMT, with the adaptability to optimize a variety of parameters including geometrical and relative phase shift configurations.
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Affiliation(s)
- Erin Iredale
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Andrew Deweyert
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Douglas A Hoover
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.,London Regional Cancer Program, London Health Sciences Centre, London, ON, Canada
| | - Jeff Z Chen
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.,London Regional Cancer Program, London Health Sciences Centre, London, ON, Canada
| | - Susanne Schmid
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Matthew O Hebb
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.,Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Terry M Peters
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.,Robarts Research Institute, Western University, London, ON, Canada
| | - Eugene Wong
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.,Department of Physics and Astronomy, Western University, London, ON, Canada
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9
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Khadka N, Harmsen IE, Lozano AM, Bikson M. Bio-Heat Model of Kilohertz-Frequency Deep Brain Stimulation Increases Brain Tissue Temperature. Neuromodulation 2020; 23:489-495. [PMID: 32058634 DOI: 10.1111/ner.13120] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 12/18/2019] [Accepted: 01/14/2020] [Indexed: 12/24/2022]
Abstract
OBJECTIVES Early clinical trials suggest that deep brain stimulation at kilohertz frequencies (10 kHz-DBS) may be effective in improving motor symptoms in patients with movement disorders. The 10 kHz-DBS can deliver significantly more power in tissue compared to conventional frequency DBS, reflecting increased pulse compression (duty cycle). We hypothesize that 10 kHz-DBS modulates neuronal function through moderate local tissue heating, analogous to kilohertz spinal cord stimulation (10 kHz-SCS). To establish the role of tissue heating in 10 kHz-DBS (30 μs, 10 kHz, at intensities of 3-7 mApeak ), a decisive first step is to characterize the range of temperature changes during clinical kHz-DBS protocols. MATERIALS AND METHODS We developed a high-resolution magnetic resonance imaging-derived DBS model incorporating joule-heat coupled bio-heat multi-physics to establish the role of tissue heating. Volume of tissue activated (VTA) under assumptions of activating function (for 130 Hz) or heating (for 10 kHz) based neuromodulation are contrasted. RESULTS DBS waveform power (waveform RMS) determined joule heating at the deep brain tissues. Peak heating was supralinearly dependent on stimulation RMS. The 10 kHz-DBS stimulation with 2.3 to 5.4 mARMS (corresponding to 3 to 7 mApeak ) produced 0.10 to 1.38°C heating at the subthalamic nucleus (STN) target under standard tissue parameters. Maximum temperature increases were predicted inside the electrode encapsulation layer (enCAP) with 2.3 to 5.4 mARMS producing 0.13 to 1.87°C under standard tissue parameters. Tissue parameter analysis predicted STN heating was especially sensitive (ranging from 0.44 to 1.35°C at 3.8 mARMS ) to decreasing enCAP electrical conductivity and decreasing STN thermal conductivity. CONCLUSIONS Subject to validation with in vivo measurements, neuromodulation through a heating mechanism of action by 10 kHz-DBS can indicate novel therapeutic pathways and strategies for dose optimization.
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Affiliation(s)
- Niranjan Khadka
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA
| | - Irene E Harmsen
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Toronto, ON, Canada
| | - Andres M Lozano
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Toronto, ON, Canada
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA
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10
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Vorwerk J, Brock AA, Anderson DN, Rolston JD, Butson CR. A retrospective evaluation of automated optimization of deep brain stimulation parameters. J Neural Eng 2019; 16:064002. [PMID: 31344689 PMCID: PMC7759010 DOI: 10.1088/1741-2552/ab35b1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
OBJECTIVE We performed a retrospective analysis of an optimization algorithm for the computation of patient-specific multipolar stimulation configurations employing multiple independent current/voltage sources. We evaluated whether the obtained stimulation configurations align with clinical data and whether the optimized stimulation configurations have the potential to lead to an equal or better stimulation of the target region as manual programming, while reducing the time required for programming sessions. APPROACH For three patients (five electrodes) diagnosed with essential tremor, we derived optimized multipolar stimulation configurations using an approach that is suitable for the application in clinical practice. To evaluate the automatically derived stimulation settings, we compared them to the results of the monopolar review. MAIN RESULTS We observe a good agreement between the findings of the monopolar review and the optimized stimulation configurations, with the algorithm assigning the maximal voltage in the optimized multipolar pattern to the contact that was found to lead to the best therapeutic effect in the clinical monopolar review in all cases. Additionally, our simulation results predict that the optimized stimulation settings lead to the activation of an equal or larger volume fraction of the target compared to the manually determined settings in all cases. SIGNIFICANCE Our results demonstrate the feasibility of an automatic determination of optimal DBS configurations and motivate a further evaluation of the applied optimization algorithm.
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Affiliation(s)
- Johannes Vorwerk
- Scientific Computing & Imaging (SCI) Institute, University of Utah, Salt Lake City, Utah, USA,Institute of Electrical and Biomedical Engineering, UMIT - Private University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Andrea A. Brock
- Scientific Computing & Imaging (SCI) Institute, University of Utah, Salt Lake City, Utah, USA,Department of Neurosurgery, University of Utah, Salt Lake City, Utah, USA
| | - Daria N. Anderson
- Scientific Computing & Imaging (SCI) Institute, University of Utah, Salt Lake City, Utah, USA,Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
| | - John D. Rolston
- Department of Neurosurgery, University of Utah, Salt Lake City, Utah, USA,Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
| | - Christopher R. Butson
- Scientific Computing & Imaging (SCI) Institute, University of Utah, Salt Lake City, Utah, USA,Department of Neurosurgery, University of Utah, Salt Lake City, Utah, USA,Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA,Departments of Psychiatry and Neurology, University of Utah, Salt Lake City, Utah, USA,Correspondig Author.
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11
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Khadka N, Truong DQ, Williams P, Martin JH, Bikson M. The Quasi-uniform assumption for Spinal Cord Stimulation translational research. J Neurosci Methods 2019; 328:108446. [PMID: 31589892 DOI: 10.1016/j.jneumeth.2019.108446] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 09/23/2019] [Accepted: 09/25/2019] [Indexed: 12/18/2022]
Abstract
BACKGROUND Quasi-uniform assumption is a general theory that postulates local electric field predicts neuronal activation. Computational current flow model of spinal cord stimulation (SCS) of humans and animal models inform how the quasi-uniform assumption can support scaling neuromodulation dose between humans and translational animal. NEW METHOD Here we developed finite element models of cat and rat SCS, and brain slice, alongside SCS models. Boundary conditions related to species specific electrode dimensions applied, and electric fields per unit current (mA) predicted. RESULTS Clinically and across animal, electric fields change abruptly over small distance compared to the neuronal morphology, such that each neuron is exposed to multiple electric fields. Per unit current, electric fields generally decrease with body mass, but not necessarily and proportionally across tissues. Peak electric field in dorsal column rat and cat were ∼17x and ∼1x of clinical values, for scaled electrodes and equal current. Within the spinal cord, the electric field for rat, cat, and human decreased to 50% of peak value caudo-rostrally (C5-C6) at 0.48 mm, 3.2 mm, and 8 mm, and mediolaterally at 0.14 mm, 2.3 mm, and 3.1 mm. Because these space constants are different, electric field across species cannot be matched without selecting a region of interest (ROI). COMPARISON WITH EXISTING METHOD This is the first computational model to support scaling neuromodulation dose between humans and translational animal. CONCLUSIONS Inter-species reproduction of the electric field profile across the entire surface of neuron populations is intractable. Approximating quasi-uniform electric field in a ROI is a rational step to translational scaling.
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Affiliation(s)
- Niranjan Khadka
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA.
| | - Dennis Q Truong
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA
| | - Preston Williams
- Department of Molecular, Cellular, and Biomedical Sciences, City University of NY School of Medicine, New York, NY, 10031, USA
| | - John H Martin
- CUNY Graduate Center, New York, NY, 10031, USA; Department of Molecular, Cellular, and Biomedical Sciences, City University of NY School of Medicine, New York, NY, 10031, USA
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA.
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