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Waataja JJ, Honda CN, Asp AJ, Nihilani RK, Farajidavar A. The Duration and Intensity of High Frequency Alternating Current Influences the Degree and Recovery of Nerve Conduction Block. IEEE Trans Biomed Eng 2024; 71:2170-2179. [PMID: 38335073 DOI: 10.1109/tbme.2024.3364350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2024]
Abstract
OBJECTIVE The purpose of this paper is to investigate the persistence of nerve blockade beyond the duration of applying high frequency alternating current (HFAC) to thinly myelinated and non-myelinated fibers, also termed a "carry-over effect". METHODS In this study, we used electrically-evoked compound action potentials from isolated rat vagus nerves to assess the influence of 5 kHz HFAC amplitude and duration on the degree of the carry-over effect. Current amplitudes from 1-10 mA and 5 kHz durations from 10-120 seconds were tested. RESULTS By testing 20 different combinations of 5 kHz amplitude and duration, we found a significant interaction between 5 kHz amplitude and duration on influencing the carry-over effect. CONCLUSION The degree of carry-over effect was dependent on 5 kHz amplitude, as well as duration. SIGNIFICANCE Utilizing the carry-over effect may be useful in designing energy efficient nerve blocking algorithms for the treatment of diseases influenced by nerve activity.
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Lee JI, Werginz P, Kameneva T, Im M, Fried SI. Membrane depolarization mediates both the inhibition of neural activity and cell-type-differences in response to high-frequency stimulation. Commun Biol 2024; 7:734. [PMID: 38890481 PMCID: PMC11189419 DOI: 10.1038/s42003-024-06359-3] [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: 03/16/2023] [Accepted: 05/20/2024] [Indexed: 06/20/2024] Open
Abstract
Neuromodulation using high frequency (>1 kHz) electric stimulation (HFS) enables preferential activation or inhibition of individual neural types, offering the possibility of more effective treatments across a broad spectrum of neurological diseases. To improve effectiveness, it is important to better understand the mechanisms governing activation and inhibition with HFS so that selectivity can be optimized. In this study, we measure the membrane potential (Vm) and spiking responses of ON and OFF α-sustained retinal ganglion cells (RGCs) to a wide range of stimulus frequencies (100-2500 Hz) and amplitudes (10-100 µA). Our findings indicate that HFS induces shifts in Vm, with both the strength and polarity of the shifts dependent on the stimulus conditions. Spiking responses in each cell directly correlate with the shifts in Vm, where strong depolarization leads to spiking suppression. Comparisons between the two cell types reveal that ON cells are more depolarized by a given amplitude of HFS than OFF cells-this sensitivity difference enables the selective targeting. Computational modeling indicates that ion-channel dynamics largely account for the shifts in Vm, suggesting that a better understanding of the differences in ion-channel properties across cell types may improve the selectivity and ultimately, enhance HFS-based neurostimulation strategies.
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Affiliation(s)
- Jae-Ik Lee
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Paul Werginz
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Institute of Biomedical Electronics, TU Wien, Vienna, Austria
| | - Tatiana Kameneva
- School of Science, Computing, and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC, Australia
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC, Australia
| | - Maesoon Im
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, South Korea
- Division of Bio-Medical Science & Technology, KIST School, University of Science and Technology (UST), Seoul, South Korea
- KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul, Republic of Korea
| | - Shelley I Fried
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Boston VA Healthcare System, Rehabilitation, Research and Development, Boston, MA, USA
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Dewberry LS, Porche K, Koenig T, Allen KD, Otto KJ. High frequency alternating current neurostimulation decreases nocifensive behavior in a disc herniation model of lumbar radiculopathy. Bioelectron Med 2023; 9:15. [PMID: 37434246 DOI: 10.1186/s42234-023-00119-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 06/19/2023] [Indexed: 07/13/2023] Open
Abstract
BACKGROUND The purpose of this study was to evaluate if kilohertz frequency alternating current (KHFAC) stimulation of peripheral nerve could serve as a treatment for lumbar radiculopathy. Prior work shows that KHFAC stimulation can treat sciatica resulting from chronic sciatic nerve constriction. Here, we evaluate if KHFAC stimulation is also beneficial in a more physiologic model of low back pain which mimics nucleus pulposus (NP) impingement of a lumbar dorsal root ganglion (DRG). METHODS To mimic a lumbar radiculopathy, autologous tail NP was harvested and placed upon the right L5 nerve root and DRG. During the same surgery, a cuff electrode was implanted around the sciatic nerve with wires routed to a headcap for delivery of KHFAC stimulation. Male Lewis rats (3 mo., n = 18) were separated into 3 groups: NP injury + KHFAC stimulation (n = 7), NP injury + sham cuff (n = 6), and sham injury + sham cuff (n = 5). Prior to surgery and for 2 weeks following surgery, animal tactile sensitivity, gait, and static weight bearing were evaluated. RESULTS KHFAC stimulation of the sciatic nerve decreased behavioral evidence of pain and disability. Without KHFAC stimulation, injured animals had heightened tactile sensitivity compared to baseline (p < 0.05), with tactile allodynia reversed during KHFAC stimulation (p < 0.01). Midfoot flexion during locomotion was decreased after injury but improved with KHFAC stimulation (p < 0.05). Animals also placed more weight on their injured limb when KHFAC stimulation was applied (p < 0.05). Electrophysiology measurements at end point showed decreased, but not blocked, compound nerve action potentials with KHFAC stimulation (p < 0.05). CONCLUSIONS KHFAC stimulation decreases hypersensitivity but does not cause additional gait compensations. This supports the idea that KHFAC stimulation applied to a peripheral nerve may be able to treat chronic pain resulting from sciatic nerve root inflammation.
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Affiliation(s)
- Lauren Savannah Dewberry
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Dr. JG56, P.O. Box 116131, Gainesville, FL, 32611, USA
| | - Ken Porche
- Lillian S Wells Department of Neurosurgery at the University of Florida, College of Medicine, 1505 SW Archer Road Gainesville, FL, 32608, Gainesville, USA
| | - Travis Koenig
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Dr. JG56, P.O. Box 116131, Gainesville, FL, 32611, USA
| | - Kyle D Allen
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Dr. JG56, P.O. Box 116131, Gainesville, FL, 32611, USA
- Pain Research & Intervention Center of Excellence, University of Florida, CTSI 2004 Mowry Road, Gainesville, FL, USA
- Department of Orthopedics and Sports Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Kevin J Otto
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Dr. JG56, P.O. Box 116131, Gainesville, FL, 32611, USA.
- Department of Neuroscience, University of Florida, 1149 Newell Dr. L1-100, P.O. Box 100244, Gainesville, FL, USA.
- Department of Electrical and Computer Engineering, University of Florida, 968 Center Dr, Gainesville, FL, 32611, USA.
- Department of Chemical Engineering, University of Florida, 1030 Center Drive, P.O. Box 116005, Gainesville, FL, 32611, USA.
- Department of Materials Science and Engineering, University of Florida, 549 Gale Lemerand Dr, P.O. Box 116400, Gainesville, FL, 32611, USA.
- Department of Neurology, 1149 Newell Dr, P.O. Box 100236, Gainesville, FL, L3-10032610, USA.
- Nanoscience Institute for Medical and Engineering Technology (NIMET), University of Florida, 1041 Center Drive, Gainesville, FL, 32611, USA.
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Peña E, Pelot NA, Grill WM. Spatiotemporal parameters for energy efficient kilohertz-frequency nerve block with low onset response. J Neuroeng Rehabil 2023; 20:72. [PMID: 37271812 PMCID: PMC10240787 DOI: 10.1186/s12984-023-01195-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/23/2023] [Indexed: 06/06/2023] Open
Abstract
BACKGROUND Electrical nerve conduction block has great potential for treatment of disease through reversible and local inactivation of somatic and autonomic nerves. However, the relatively high energy requirements and the presence of undesired excitation at the onset of the kilohertz-frequency (KHF) signals used for block pose obstacles to effective translation. Frequency, electrode geometry, and waveform shape are known to influence block threshold and onset response, but available data provide a limited understanding of how to select these parameters to optimize nerve block. METHODS We evaluated KHF nerve block in rat tibial nerve across frequencies (5-60 kHz), electrode geometries (monopolar, bipolar, and tripolar), and waveform shapes. We present a novel Fourier-based method for constructing composite signals that systematically sample the KHF waveform design space. RESULTS The lowest frequencies capable of blocking (5-16 kHz) were not the most energy-efficient among the tested frequencies. Further, bipolar cuffs required the largest current and power to block, monopolar cuffs required the lowest current, and both tripolar and monopolar cuffs required the lowest power. Tripolar cuffs produced the smallest onset response across frequencies. Composite signals comprised of a first harmonic sinusoid at fundamental frequency (f0) superposed on a second harmonic sinusoid at 2f0 could block at lower threshold and lower onset response compared to the constituent sinusoids alone. This effect was strongly dependent on the phase of the second harmonic and on the relative amplitudes of the first and second harmonics. This effect was also dependent on electrode geometry: monopolar and tripolar cuffs showed clear composite signal effects in most experiments; bipolar cuffs showed no clear effects in most experiments. CONCLUSIONS Our data provide novel information about block threshold and onset response at the boundary of frequencies that can block. Our results also show an interaction between spatial (cuff geometry) and temporal (frequency and waveform shape) parameters. Finally, while previous studies suggested that temporal parameters could reduce onset response only in exchange for increased block threshold (or vice versa), our results show that waveform shape influences KHF response in ways that can be exploited to reduce both energy and onset responses.
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Affiliation(s)
- Edgar Peña
- Department of Biomedical Engineering, Duke University, Room 1427, Fitzpatrick CIEMAS, 101 Science Drive Campus Box 90281, Durham, NC, 27708, USA
| | - Nicole A Pelot
- Department of Biomedical Engineering, Duke University, Room 1427, Fitzpatrick CIEMAS, 101 Science Drive Campus Box 90281, Durham, NC, 27708, USA
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Room 1427, Fitzpatrick CIEMAS, 101 Science Drive Campus Box 90281, Durham, NC, 27708, USA.
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA.
- Department of Neurobiology, Duke University School of Medicine, Durham, NC, USA.
- Department of Neurosurgery, Duke University School of Medicine, Durham, NC, USA.
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Chung WH, Lin YN, Wu MY, Chang KC. Sympathetic Modulation in Cardiac Arrhythmias: Where We Stand and Where We Go. J Pers Med 2023; 13:jpm13050786. [PMID: 37240956 DOI: 10.3390/jpm13050786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 04/27/2023] [Accepted: 04/29/2023] [Indexed: 05/28/2023] Open
Abstract
The nuance of autonomic cardiac control has been studied for more than 400 years, yet little is understood. This review aimed to provide a comprehensive overview of the current understanding, clinical implications, and ongoing studies of cardiac sympathetic modulation and its anti-ventricular arrhythmias' therapeutic potential. Molecular-level studies and clinical studies were reviewed to elucidate the gaps in knowledge and the possible future directions for these strategies to be translated into the clinical setting. Imbalanced sympathoexcitation and parasympathetic withdrawal destabilize cardiac electrophysiology and confer the development of ventricular arrhythmias. Therefore, the current strategy for rebalancing the autonomic system includes attenuating sympathoexcitation and increasing vagal tone. Multilevel targets of the cardiac neuraxis exist, and some have emerged as promising antiarrhythmic strategies. These interventions include pharmacological blockade, permanent cardiac sympathetic denervation, temporal cardiac sympathetic denervation, etc. The gold standard approach, however, has not been known. Although neuromodulatory strategies have been shown to be highly effective in several acute animal studies with very promising results, the individual and interspecies variation between human autonomic systems limits the progress in this young field. There is, however, still much room to refine the current neuromodulation therapy to meet the unmet need for life-threatening ventricular arrhythmias.
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Affiliation(s)
- Wei-Hsin Chung
- Division of Cardiovascular Medicine, Department of Medicine, China Medical University Hospital, Taichung 40447, Taiwan
- UCLA Cardiac Arrhythmia Center, Ronald Reagan UCLA Medical Center, Los Angeles, CA 90024, USA
| | - Yen-Nien Lin
- Division of Cardiovascular Medicine, Department of Medicine, China Medical University Hospital, Taichung 40447, Taiwan
- School of Medicine, China Medical University, Taichung 404333, Taiwan
| | - Mei-Yao Wu
- School of Post-Baccalaureate Chinese Medicine, China Medical University, Taichung 404333, Taiwan
- Department of Chinese Medicine, China Medical University Hospital, Taichung 40447, Taiwan
| | - Kuan-Cheng Chang
- Division of Cardiovascular Medicine, Department of Medicine, China Medical University Hospital, Taichung 40447, Taiwan
- School of Medicine, China Medical University, Taichung 404333, Taiwan
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Jian J, Wang J, Shen B, Shen Z, Goosby K, Scolieri J, Beckel J, de Groat WC, Tai C. Pudendal Nerve Block by Adaptively Stepwise Increasing the Intensity of High-Frequency (10 kHz) Biphasic Stimulation. Neuromodulation 2023:S1094-7159(23)00149-6. [PMID: 37125972 PMCID: PMC10613126 DOI: 10.1016/j.neurom.2023.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 03/14/2023] [Accepted: 03/29/2023] [Indexed: 05/02/2023]
Abstract
OBJECTIVE The purpose of this study is to determine whether adaptively stepwise increasing the intensity of a high-frequency (10 kHz) biphasic stimulation (HFBS) can produce nerve conduction block without generating a large initial response. MATERIALS AND METHODS In anesthetized cats, three cuff electrodes were implanted on the left pudendal nerve for stimulation or block. The urethral pressure increase induced by pudendal nerve stimulation was used to measure the pudendal nerve block induced by HFBS. RESULTS HFBS applied suddenly with a large step increase in intensity induced a large (86 ± 16 cmH2O) urethral pressure increase before it blocked pudendal nerve conduction. However, HFBS applied by adaptively stepwise increasing the intensity every 10 to 60 seconds over a long period (33-301 minutes; average 108 ± 35 minutes) with many small intensity increases (0.005-0.1 mA) induced no response or low-amplitude high-frequency urethral pressure changes before it blocked pudendal nerve conduction. The minimal HFBS intensities required by the two different methods to block pudendal nerve conduction are similar. CONCLUSION This study is important for better understanding the possible mechanisms underlying the HFBS-induced nerve block and provides the possibility of developing a new nerve block method for clinical applications in which an initial large response is a concern.
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Affiliation(s)
- Jianan Jian
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jicheng Wang
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bing Shen
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Zhijun Shen
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Khari Goosby
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Joseph Scolieri
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jonathan Beckel
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - William C de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Changfeng Tai
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
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Zhong Y, Wang J, Beckel J, de Groat WC, Tai C. Mechanisms Underlying Poststimulation Block Induced by High-Frequency Biphasic Stimulation. Neuromodulation 2023; 26:577-588. [PMID: 34278654 PMCID: PMC8766610 DOI: 10.1111/ner.13501] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/30/2021] [Accepted: 06/21/2021] [Indexed: 01/21/2023]
Abstract
OBJECTIVE To reveal the possible mechanisms underlying poststimulation block induced by high-frequency biphasic stimulation (HFBS). MATERIALS AND METHODS A new axonal conduction model is developed for unmyelinated axons. This new model is different from the classical axonal conduction model by including both ion concentrations and membrane ion pumps to allow analysis of axonal responses to long-duration stimulation. Using the new model, the post-HFBS block phenomenon reported in animal studies is simulated and analyzed for a wide range of stimulation frequencies (100 Hz-10 kHz). RESULTS HFBS can significantly change the Na+ and K+ concentrations inside and outside the axon to produce a post-HFBS block of either short-duration (<500 msec) or long-duration (>3 sec) depending on the duration of HFBS. The short-duration block is due to the fast recovery of the Na+ and K+ concentrations outside the axon in periaxonal space by diffusion of ions into and from the large extracellular space, while the long-duration block is due to the slow restoration of the normal Na+ concentration inside the axon by membrane ion pumps. The 100 Hz HFBS requires the minimal electrical energy to achieve the post-HFBS block, while the 10 kHz stimulation is the least effective frequency requiring high intensity and long duration to achieve the block. CONCLUSION This study reveals two possible ionic mechanisms underlying post-HFBS block of axonal conduction. Understanding these mechanisms is important for improving clinical applications of HFBS block and for developing new nerve block methods employing HFBS.
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Affiliation(s)
- Yihua Zhong
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA; School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Jicheng Wang
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jonathan Beckel
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - William C de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Changfeng Tai
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
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Lee G, Ray E, Yoon HJ, Genovese S, Choi YS, Lee MK, Şahin S, Yan Y, Ahn HY, Bandodkar AJ, Kim J, Park M, Ryu H, Kwak SS, Jung YH, Odabas A, Khandpur U, Ray WZ, MacEwan MR, Rogers JA. A bioresorbable peripheral nerve stimulator for electronic pain block. SCIENCE ADVANCES 2022; 8:eabp9169. [PMID: 36197971 PMCID: PMC9534494 DOI: 10.1126/sciadv.abp9169] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 08/18/2022] [Indexed: 05/31/2023]
Abstract
Local electrical stimulation of peripheral nerves can block the propagation of action potentials, as an attractive alternative to pharmacological agents for the treatment of acute pain. Traditional hardware for such purposes, however, involves interfaces that can damage nerve tissue and, when used for temporary pain relief, that impose costs and risks due to requirements for surgical extraction after a period of need. Here, we introduce a bioresorbable nerve stimulator that enables electrical nerve block and associated pain mitigation without these drawbacks. This platform combines a collection of bioresorbable materials in architectures that support stable blocking with minimal adverse mechanical, electrical, or biochemical effects. Optimized designs ensure that the device disappears harmlessly in the body after a desired period of use. Studies in live animal models illustrate capabilities for complete nerve block and other key features of the technology. In certain clinically relevant scenarios, such approaches may reduce or eliminate the need for use of highly addictive drugs such as opioids.
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Affiliation(s)
- Geumbee Lee
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
- Precision Biology Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Emily Ray
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
- Department of Neurological Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Hong-Joon Yoon
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
| | - Sabrina Genovese
- Department of Neurological Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Yeon Sik Choi
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
| | - Min-Kyu Lee
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
| | - Samet Şahin
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
- Department of Bioengineering, Bilecik Şeyh Edebali University, 11230 Bilecik, Merkez/Bilecik, Turkey
| | - Ying Yan
- Department of Neurological Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Hak-Young Ahn
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
| | - Amay J. Bandodkar
- Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, NC 27606, USA
- Center for Advanced Self-Powered Systems of Integrated Sensors and Technologies (ASSIST), North Carolina State University, Raleigh, NC 27606, USA
| | - Joohee Kim
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
| | - Minsu Park
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
| | - Hanjun Ryu
- Department of Advanced Materials Engineering, Chung-Ang University, Anseong 17546, Republic of Korea
| | - Sung Soo Kwak
- Center for Bionics, Biomedical Research Division, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Yei Hwan Jung
- Department of Electronic Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Arman Odabas
- Department of Neurological Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
- Department of Internal Medicine, Stanford University Medical Center, Stanford, CA 94305, USA
| | - Umang Khandpur
- Department of Neurological Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Wilson Z. Ray
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
- Department of Neurological Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Matthew R. MacEwan
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
- Department of Neurological Surgery, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - John A. Rogers
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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Coolen RL, Emmer KM, Spantidea PI, van Asselt E, Scheepe JR, Serdijn WA, Blok BFM. Kilohertz alternating current neuromodulation of the pudendal nerves: effects on the anal canal and anal sphincter in rats. J Appl Biomed 2022; 20:56-69. [PMID: 35727123 DOI: 10.32725/jab.2022.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 06/21/2022] [Indexed: 11/05/2022] Open
Abstract
The first two objectives were to establish which stimulation parameters of kilohertz frequency alternating current (KHFAC) neuromodulation influence the effectiveness of pudendal nerve block and its safety. The third aim was to determine whether KHFAC neuromodulation of the pudendal nerve can relax the pelvic musculature, including the anal sphincter. Simulation experiments were conducted to establish which parameters can be adjusted to improve the effectiveness and safety of the nerve block. The outcome measures were block threshold (measure of effectiveness) and block threshold charge per phase (measure of safety). In vivo, the pudendal nerves in 11 male and 2 female anesthetized Sprague Dawley rats were stimulated in the range of 10 Hz to 40 kHz, and the effect on anal pressure was measured. The simulations showed that block threshold and block threshold charge per phase depend on waveform, interphase delay, electrode-to-axon distance, interpolar distance, and electrode array orientation. In vivo, the average anal pressure during unilateral KHFAC stimulation was significantly lower than the average peak anal pressure during low-frequency stimulation (p < 0.001). Stimulation with 20 kHz and 40 kHz (square wave, 10 V amplitude, 50% duty cycle, no interphase delay) induced the largest anal pressure decrease during both unilateral and bilateral stimulation. However, no statistically significant differences were detected between the different frequencies. This study showed that waveform, interphase delay and the alignment of the electrode along the nerve affect the effectiveness and safety of KHFAC stimulation. Additionally, we showed that KHFAC neuromodulation of the pudendal nerves with an electrode array effectively reduces anal pressure in rats.
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Affiliation(s)
- Rosa L Coolen
- Erasmus Medical Center, Department of Urology, Rotterdam, Zuid-Holland, Netherlands
| | - Koen M Emmer
- Delft University of Technology, Section Bioelectronics, Delft, Zuid-Holland, Netherlands
| | | | - Els van Asselt
- Erasmus Medical Center, Department of Urology, Rotterdam, Zuid-Holland, Netherlands
| | - Jeroen R Scheepe
- Erasmus Medical Center, Department of Urology, Rotterdam, Zuid-Holland, Netherlands
| | - Wouter A Serdijn
- Delft University of Technology, Section Bioelectronics, Delft, Zuid-Holland, Netherlands
| | - Bertil F M Blok
- Erasmus Medical Center, Department of Urology, Rotterdam, Zuid-Holland, Netherlands
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Verma N, Graham RD, Mudge J, Trevathan JK, Franke M, Shoffstall AJ, Williams J, Dalrymple AN, Fisher LE, Weber DJ, Lempka SF, Ludwig KA. Augmented Transcutaneous Stimulation Using an Injectable Electrode: A Computational Study. Front Bioeng Biotechnol 2021; 9:796042. [PMID: 34988068 PMCID: PMC8722711 DOI: 10.3389/fbioe.2021.796042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 11/25/2021] [Indexed: 11/13/2022] Open
Abstract
Minimally invasive neuromodulation technologies seek to marry the neural selectivity of implantable devices with the low-cost and non-invasive nature of transcutaneous electrical stimulation (TES). The Injectrode® is a needle-delivered electrode that is injected onto neural structures under image guidance. Power is then transcutaneously delivered to the Injectrode using surface electrodes. The Injectrode serves as a low-impedance conduit to guide current to the deep on-target nerve, reducing activation thresholds by an order of magnitude compared to using only surface stimulation electrodes. To minimize off-target recruitment of cutaneous fibers, the energy transfer efficiency from the surface electrodes to the Injectrode must be optimized. TES energy is transferred to the Injectrode through both capacitive and resistive mechanisms. Electrostatic finite element models generally used in TES research consider only the resistive means of energy transfer by defining tissue conductivities. Here, we present an electroquasistatic model, taking into consideration both the conductivity and permittivity of tissue, to understand transcutaneous power delivery to the Injectrode. The model was validated with measurements taken from (n = 4) swine cadavers. We used the validated model to investigate system and anatomic parameters that influence the coupling efficiency of the Injectrode energy delivery system. Our work suggests the relevance of electroquasistatic models to account for capacitive charge transfer mechanisms when studying TES, particularly when high-frequency voltage components are present, such as those used for voltage-controlled pulses and sinusoidal nerve blocks.
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Affiliation(s)
- Nishant Verma
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States
- Wisconsin Institute for Translational Neuroengineering (WITNe)–Madison, Madison, WI, United States
| | - Robert D. Graham
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States
| | - Jonah Mudge
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States
- Wisconsin Institute for Translational Neuroengineering (WITNe)–Madison, Madison, WI, United States
| | - James K. Trevathan
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States
- Wisconsin Institute for Translational Neuroengineering (WITNe)–Madison, Madison, WI, United States
| | | | - Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Justin Williams
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States
- Wisconsin Institute for Translational Neuroengineering (WITNe)–Madison, Madison, WI, United States
| | - Ashley N. Dalrymple
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States
- Rehab Neural Engineering Labs (RNEL), Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States
| | - Lee E. Fisher
- Rehab Neural Engineering Labs (RNEL), Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States
| | - Douglas J. Weber
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States
- Rehab Neural Engineering Labs (RNEL), Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States
| | - Scott F. Lempka
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States
| | - Kip A. Ludwig
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States
- Wisconsin Institute for Translational Neuroengineering (WITNe)–Madison, Madison, WI, United States
- Department of Neurosurgery, University of Wisconsin–Madison, Madison, WI, United States
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11
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Liu J, Ganeshbabu N, Shalaby N, Chen L, Guo T, Feng B. Targeting Two-Pore-Domain Potassium Channels by Mechanical Stretch Instantaneously Modulates Action Potential Transmission in Mouse Sciatic Nerves. ACS Chem Neurosci 2021; 12:3558-3566. [PMID: 34423641 DOI: 10.1021/acschemneuro.1c00052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Recent reports indicate dominant roles of TRAAK and TREK-1 channels, i.e., mechanosensitive two-pore-domain potassium channels (K2P) at the nodes of Ranvier for action potential repolarization in mammalian peripheral nerves. Functional changes in mammalian peripheral nerve conduction by mechanical stretch studied by recording compound action potentials lack the necessary resolution to detect subtle neuromodulatory effects on conduction velocity. In this study, we developed a novel in vitro approach that enables single-fiber recordings from individual mouse sciatic nerve axons while delivering computer-controlled stepped stretch to the sciatic nerve trunk. Axial stretch instantaneously increased the conduction delay in both myelinated A-fibers and unmyelinated C-fibers. Increases in conduction delay linearly correlated with increases in axial stretch ratio for both A- and C-fibers. The slope of the increase in conduction delay versus stretch ratio was steeper in C-fibers than in A-fibers. Moderate axial stretch (14-19% of in vitro length) reversibly blocked 37.5% of unmyelinated C-fibers but none of the eight myelinated A-fibers tested. Application of arachidonic acid, an agonist to TRAAK and TREK-1 to sciatic nerve trunk, blocks axonal transmission in both A- and C-fibers with delayed onset and prolonged block. Also, the application of an antagonist ruthenium red showed a tendency of suppressing the stretch-evoked increase in conduction delay. These results could draw focused research on pharmacological and mechanical activation of K2P channels as a novel neuromodulatory strategy to achieve peripheral nerve block.
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Affiliation(s)
- Jia Liu
- Department of Biomedical Engineering, University of Connecticut, 260 Glenbrook Road, Storrs, Connecticut 06269, United States
| | - Nishanth Ganeshbabu
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Noha Shalaby
- Department of Biomedical Engineering, University of Connecticut, 260 Glenbrook Road, Storrs, Connecticut 06269, United States
| | - Longtu Chen
- Department of Biomedical Engineering, University of Connecticut, 260 Glenbrook Road, Storrs, Connecticut 06269, United States
| | - Tiantian Guo
- Department of Biomedical Engineering, University of Connecticut, 260 Glenbrook Road, Storrs, Connecticut 06269, United States
| | - Bin Feng
- Department of Biomedical Engineering, University of Connecticut, 260 Glenbrook Road, Storrs, Connecticut 06269, United States
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12
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Abstract
Electric currents can produce quick, reversible control of neural activity. Externally applied electric currents have been used in inhibiting certain ganglion cells in clinical practices. Via electromagnetic induction, a miniature-sized magnetic coil could provide focal stimulation to the ganglion neurons. Here we report that high-frequency stimulation with the miniature coil could reversibly block ganglion cell activity in marine mollusk Aplysia californica, regardless the firing frequency of the neurons, or concentration of potassium ions around the ganglion neurons. Presence of the ganglion sheath has minimal impact on the inhibitory effects of the coil. The inhibitory effect was local to the soma, and was sufficient in blocking the neuron's functional output. Biophysical modeling confirmed that the miniature coil induced a sufficient electric field in the vicinity of the targeted soma. Using a multi-compartment model of Aplysia ganglion neuron, we found that the high-frequency magnetic stimuli altered the ion channel dynamics that were essential for the sustained firing of action potentials in the soma. Results from this study produces several critical insights to further developing the miniature coil technology for neural control by targeting ganglion cells. The miniature coil provides an interesting neural modulation strategy in clinical applications and laboratory research.
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Affiliation(s)
- Hui Ye
- Department of Biology, Quinlan Life Sciences Education and Research Center, Loyola University Chicago, 1032 W. Sheridan Rd., Chicago, IL, 60660, USA.
| | - Lauryn Barrett
- Department of Biology, Quinlan Life Sciences Education and Research Center, Loyola University Chicago, 1032 W. Sheridan Rd., Chicago, IL, 60660, USA
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13
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Neudorfer C, Chow CT, Boutet A, Loh A, Germann J, Elias GJ, Hutchison WD, Lozano AM. Kilohertz-frequency stimulation of the nervous system: A review of underlying mechanisms. Brain Stimul 2021; 14:513-530. [PMID: 33757930 DOI: 10.1016/j.brs.2021.03.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 03/08/2021] [Accepted: 03/11/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Electrical stimulation in the kilohertz-frequency range has gained interest in the field of neuroscience. The mechanisms underlying stimulation in this frequency range, however, are poorly characterized to date. OBJECTIVE/HYPOTHESIS To summarize the manifold biological effects elicited by kilohertz-frequency stimulation in the context of the currently existing literature and provide a mechanistic framework for the neural responses observed in this frequency range. METHODS A comprehensive search of the peer-reviewed literature was conducted across electronic databases. Relevant computational, clinical, and mechanistic studies were selected for review. RESULTS The effects of kilohertz-frequency stimulation on neural tissue are diverse and yield effects that are distinct from conventional stimulation. Broadly, these can be divided into 1) subthreshold, 2) suprathreshold, 3) synaptic and 4) thermal effects. While facilitation is the dominating mechanism at the subthreshold level, desynchronization, spike-rate adaptation, conduction block, and non-monotonic activation can be observed during suprathreshold kilohertz-frequency stimulation. At the synaptic level, kilohertz-frequency stimulation has been associated with the transient depletion of the available neurotransmitter pool - also known as synaptic fatigue. Finally, thermal effects associated with extrinsic (environmental) and intrinsic (associated with kilohertz-frequency stimulation) temperature changes have been suggested to alter the neural response to stimulation paradigms. CONCLUSION The diverse spectrum of neural responses to stimulation in the kilohertz-frequency range is distinct from that associated with conventional stimulation. This offers the potential for new therapeutic avenues across stimulation modalities. However, stimulation in the kilohertz-frequency range is associated with distinct challenges and caveats that need to be considered in experimental paradigms.
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Affiliation(s)
- Clemens Neudorfer
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Canada
| | - Clement T Chow
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Canada
| | - Alexandre Boutet
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Canada
| | - Aaron Loh
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Canada
| | - Jürgen Germann
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Canada
| | - Gavin Jb Elias
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Canada
| | - William D Hutchison
- Krembil Research Institute, University of Toronto, Ontario, Canada; Department of Physiology, Toronto Western Hospital and University of Toronto, Ontario, Canada
| | - Andres M Lozano
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Canada; Krembil Research Institute, University of Toronto, Ontario, Canada.
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14
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Non-monotonic kilohertz frequency neural block thresholds arise from amplitude- and frequency-dependent charge imbalance. Sci Rep 2021; 11:5077. [PMID: 33658552 PMCID: PMC7930193 DOI: 10.1038/s41598-021-84503-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 02/17/2021] [Indexed: 12/17/2022] Open
Abstract
Reversible block of nerve conduction using kilohertz frequency electrical signals has substantial potential for treatment of disease. However, the ability to block nerve fibers selectively is limited by poor understanding of the relationship between waveform parameters and the nerve fibers that are blocked. Previous in vivo studies reported non-monotonic relationships between block signal frequency and block threshold, suggesting the potential for fiber-selective block. However, the mechanisms of non-monotonic block thresholds were unclear, and these findings were not replicated in a subsequent in vivo study. We used high-fidelity computational models and in vivo experiments in anesthetized rats to show that non-monotonic threshold-frequency relationships do occur, that they result from amplitude- and frequency-dependent charge imbalances that cause a shift between kilohertz frequency and direct current block regimes, and that these relationships can differ across fiber diameters such that smaller fibers can be blocked at lower thresholds than larger fibers. These results reconcile previous contradictory studies, clarify the mechanisms of interaction between kilohertz frequency and direct current block, and demonstrate the potential for selective block of small fiber diameters.
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15
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Skach J, Conway C, Barrett L, Ye H. Axonal blockage with microscopic magnetic stimulation. Sci Rep 2020; 10:18030. [PMID: 33093520 PMCID: PMC7582966 DOI: 10.1038/s41598-020-74891-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 10/05/2020] [Indexed: 12/27/2022] Open
Abstract
Numerous neurological dysfunctions are characterized by undesirable nerve activity. By providing reversible nerve blockage, electric stimulation with an implanted electrode holds promise in the treatment of these conditions. However, there are several limitations to its application, including poor bio-compatibility and decreased efficacy during chronic implantation. A magnetic coil of miniature size can mitigate some of these problems, by coating it with biocompatible material for chronic implantation. However, it is unknown if miniature coils could be effective in axonal blockage and, if so, what the underlying mechanisms are. Here we demonstrate that a submillimeter magnetic coil can reversibly block action potentials in the unmyelinated axons from the marine mollusk Aplysia californica. Using a multi-compartment model of the Aplysia axon, we demonstrate that the miniature coil causes a significant local depolarization in the axon, alters activation dynamics of the sodium channels, and prevents the traveling of the invading action potentials. With improved biocompatibility and capability of emitting high-frequency stimuli, micro coils provide an interesting alternative for electric blockage of axonal conductance in clinical settings.
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Affiliation(s)
- Jordan Skach
- Department of Biology, Loyola University Chicago, Chicago, IL, USA
| | - Catherine Conway
- Department of Biology, Loyola University Chicago, Chicago, IL, USA
| | - Lauryn Barrett
- Department of Biology, Loyola University Chicago, Chicago, IL, USA
| | - Hui Ye
- Department of Biology, Loyola University Chicago, Chicago, IL, USA. .,Department of Biology, Quinlan Life Sciences Education and Research Center, Loyola University Chicago, 1032 W. Sheridan Rd., Chicago, IL, 60660, USA.
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16
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Peña E, Pelot NA, Grill WM. Quantitative comparisons of block thresholds and onset responses for charge-balanced kilohertz frequency waveforms. J Neural Eng 2020; 17:046048. [PMID: 32777778 DOI: 10.1088/1741-2552/abadb5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE There is growing interest in delivering kilohertz frequency (KHF) electrical signals to block conduction in peripheral nerves for treatment of various diseases. Previous studies used different KHF waveforms to achieve block, and it remains unclear how waveform affects nerve block parameters. APPROACH We quantified the effects of waveform on KHF block of the rat tibial nerve in vivo and in computational models. We compared block thresholds and onset responses across current-controlled sinusoids and charge-balanced rectangular waveforms with different asymmetries and duty cycles. MAIN RESULTS Sine waves had higher block thresholds than square waves, but used less power at block threshold. Block threshold had an inverse relationship with duty cycle of rectangular waveforms irrespective of waveform asymmetry. Computational model results were consistent with relationships measured in vivo, although the models underestimated the effect of duty cycle on increasing thresholds. The axonal membrane substantially filtered waveforms, the filter transfer function was strikingly similar across waveforms, and filtering resulted in post-filtered rms block thresholds that were approximately constant across waveforms in silico and in vivo. Onset response was not consistently affected by waveform shape, but onset response was smaller at amplitudes well above block threshold. Therefore, waveforms with lower block thresholds (e.g. sine waves or square waves) could be more readily increased to higher amplitudes relative to block threshold to reduce onset response. We also observed a reduction in onset responses across consecutive trials after initial application of supra-block threshold amplitudes. SIGNIFICANCE Waveform had substantial effects on block thresholds, and the amplitude relative to block threshold had substantial effects on onset response. These data inform choice of waveform in subsequent studies and clinical applications, enhance effective use of block in therapeutic applications, and facilitate the design of parameters that achieve block with minimal onset responses.
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Affiliation(s)
- Edgar Peña
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
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17
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Shapiro K, Guo W, Armann K, Pace N, Shen B, Wang J, Beckel J, de Groat W, Tai C. Pudendal Nerve Block by Low-Frequency (≤1 kHz) Biphasic Electrical Stimulation. Neuromodulation 2020; 24:1012-1017. [PMID: 32762142 DOI: 10.1111/ner.13241] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 06/22/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To test the hypothesis that poststimulation block of nerve conduction can be achieved by low-frequency (≤1 kHz) biphasic stimulation (LFBS). MATERIALS AND METHODS A tripolar cuff electrode was placed around the pudendal nerve in cats to deliver LFBS (1 kHz, 500 Hz, and 100 Hz). Two bipolar hook electrodes were placed central and distal to the cuff electrode to induce external urethral sphincter (EUS) contractions. A catheter was inserted into the urethra to record EUS contraction pressure. Pudendal nerve block by LFBS was confirmed by the failure of the central hook electrode stimulation to induce EUS contractions, while the distal hook electrode stimulation still induced contractions. RESULTS Pudendal nerve conduction was completely blocked by LFBS at different frequencies (1 kHz, 500 Hz, and 100 Hz) after terminating LFBS. The post-LFBS block induced at the minimal stimulation intensity and duration was fully reversible within the same time period (10-15 min on average) for the three frequencies. However, the stimulation duration to induce block significantly (p < 0.05) increased from 23 ± 8 sec to 95 ± 14 sec when frequency increased from 100 Hz to 1 kHz. CONCLUSION This study discovered that LFBS (≤1 kHz), like high-frequency (≥5 kHz) biphasic stimulation (HFBS), can induce poststimulation block. The result provides support for the theory that biphasic stimulation waveforms block axonal conduction by changing intracellular and extracellular ion concentrations. The post-LFBS block provides the opportunity to develop new neuromodulation devices for clinical applications where initial nerve firing is acceptable.
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Affiliation(s)
- Katherine Shapiro
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Wenbin Guo
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Urology, The Third Affiliated Hospital of Southern Medical University, Guangzhou, People's Republic of China
| | - Kody Armann
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Natalie Pace
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bing Shen
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jicheng Wang
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jonathan Beckel
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, PA, USA
| | - William de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, PA, USA
| | - Changfeng Tai
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Pharmacology and Chemical Biology, University of Pittsburgh, PA, USA.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
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18
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Rapeaux A, Constandinou TG. An HFAC block-capable and module-extendable 4-channel stimulator for acute neurophysiology. J Neural Eng 2020; 17:046013. [PMID: 32428874 DOI: 10.1088/1741-2552/ab947a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE This paper describes the design, testing and use of a novel multichannel block-capable stimulator for acute neurophysiology experiments to study highly selective neural interfacing techniques. This paper demonstrates the stimulator's ability to excite and inhibit nerve activity in the rat sciatic nerve model concurrently using monophasic and biphasic nerve stimulation as well as high-frequency alternating current (HFAC). APPROACH The proposed stimulator uses a Howland Current Pump circuit as the main analogue stimulator element. 4 current output channels with a common return path were implemented on printed circuit board using Commercial Off-The-Shelf components. Programmable operation is carried out by an ARM Cortex-M4 Microcontroller on the Freescale freedom development platform (K64F). MAIN RESULTS This stimulator design achieves ± 10 mA of output current with ± 15 V of compliance and less than 6 µA of resolution using a quad-channel 12-bit external DAC, for four independently driven channels. This allows the stimulator to carry out both excitatory and inhibitory (HFAC block) stimulation. DC Output impedance is above 1 M Ω. Overall cost for materials i.e. PCB boards and electronic components is less than USD 450 or GBP 350 and device size is approximately 9 cm × 6 cm × 5 cm. SIGNIFICANCE Experimental neurophysiology often requires significant investment in bulky equipment for specific stimulation requirements, especially when using HFAC block. Different stimulators have limited means of communicating with each other, making protocols more complicated. This device provides an effective solution for multi-channel stimulation and block of nerves, enabling studies on selective neural interfacing in acute scenarios with an affordable, portable and space-saving design for the laboratory. The stimulator can be further upgraded with additional modules to extend functionality while maintaining straightforward programming and integration of functions with one controller. Additionally, all source files including all code and PCB design files are freely available to the community to use and further develop.
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Affiliation(s)
- Adrien Rapeaux
- Centre for Bio-Inspired Technology, Imperial College London , London, SW7 2AZ, United Kingdom. Department of Electrical and Electronic Engineering, Imperial College London, London, SW7 2BT, United Kingdom. Care Research & Technology Centre, UK Dementia Research Institute at Imperial College London, London, United Kingdom. Author to whom any correspondence should be addressed
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19
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Wang Z, Pace N, Cai H, Shen B, Wang J, Roppolo JR, de Groat WC, Tai C. Poststimulation Block of Pudendal Nerve Conduction by High-Frequency (kHz) Biphasic Stimulation in Cats. Neuromodulation 2019; 23:747-753. [PMID: 32840020 DOI: 10.1111/ner.13060] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 08/23/2019] [Accepted: 09/10/2019] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To determine the relationship between various parameters of high-frequency biphasic stimulation (HFBS) and the recovery period of post-HFBS block of the pudendal nerve in cats. MATERIALS AND METHODS A tripolar cuff electrode was implanted on the pudendal nerve to deliver HFBS in ten cats. Two hook electrodes were placed central or distal to the cuff electrode to stimulate the pudendal nerve and induce contractions of external urethral sphincter (EUS). A catheter was inserted toward the distal urethra to slowly perfuse the urethra and record the back-up pressure generated by EUS contractions. After determining the block threshold (T), HFBS (6 or 10 kHz) of different durations (1, 5, 10, 20, 30 min) and intensities (1T or 2T) was used to produce the post-HFBS block. RESULTS HFBS at 10 kHz and 1T intensity must be applied for at least 30 min to induce post-HFBS block. However, 10 kHz HFBS at a higher intensity (2T) elicited post-HFBS block after stimulation of only 10 min; and 10 kHz HFBS at 2T for 30 min induced a longer-lasting (1-3 h) post-HFBS block that fully recovered with time. HFBS of 5-min duration at 6 kHz produced a longer period (20.4 ± 2.1 min, p < 0.05, N = 5 cats) of post-HFBS block than HFBS at 10 kHz (9.5 ± 2.1 min). CONCLUSION HFBS of longer duration, higher intensity, and lower frequency can produce longer-lasting reversible post-HFBS block. This study is important for developing new methods to block nerve conduction by HFBS.
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Affiliation(s)
- Zhaoxia Wang
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Urology, Rehabilitation Research Centre, Rehabilitation School of Capital Medical University, Beijing, China
| | - Natalie Pace
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Haotian Cai
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA.,School of Health and Rehabilitation Science, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bing Shen
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jicheng Wang
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA
| | - James R Roppolo
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - William C de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Changfeng Tai
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
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20
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Serrano-Muñoz D, Gómez-Soriano J, Bravo-Esteban E, Ávila-Martín G, Galán-Arriero I, Taylor J, Avendaño-Coy J. Soleus H-reflex modulation following transcutaneous high- and low-frequency spinal stimulation in healthy volunteers. J Electromyogr Kinesiol 2019; 46:1-7. [DOI: 10.1016/j.jelekin.2019.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 03/04/2019] [Accepted: 03/06/2019] [Indexed: 12/22/2022] Open
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21
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Roldan LM, Eggers TE, Kilgore KL, Bhadra N, Vrabec T, Bhadra N. Measurement of block thresholds in kiloHertz frequency alternating current peripheral nerve block. J Neurosci Methods 2019; 315:48-54. [PMID: 30641091 PMCID: PMC6380354 DOI: 10.1016/j.jneumeth.2019.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 12/21/2018] [Accepted: 01/10/2019] [Indexed: 01/09/2023]
Abstract
BACKGROUND Kilohertz frequency alternating currents (KHFAC) produce rapid nerve conduction block of mammalian peripheral nerve and have potential clinical applications in reducing peripheral nerve hyperactivity. The experimental investigation of KHFAC nerve block requires a robust output measure and this has proven to be the block threshold (BT), the lowest current or voltage at which the axons of interest are completely blocked. All significant literature in KHFAC nerve block, both simulations and experimental, were reviewed to determine the block threshold method that was used. The two common methods used are the High-Low method experimentally and the Binary search method for simulations. NEW METHOD Four methods to measure the block threshold (High-Low, High-Low-High, Binary and Random) at three frequencies (10, 20 and 30 kHz) were compared through randomized repeated experiments in the in-vivo rodent sciatic nerve-gastrocnemius model. RESULTS The literature review showed that more than 50% of publications did not measure the block threshold. The experimental results showed no statistical difference in the BT value between the four methods. COMPARISON WITH EXISTING METHOD(S) However, there were differences in the number of significant onset responses, depending on the method. The run time for the BT determination was the shortest for the High-Low method. CONCLUSIONS It is recommended that all research in electrical nerve block, including KHFAC, should include measurement of the BT. The High-Low method is recommended for most experimental situations but the Binary method could also be a viable option, especially where onset responses are minimal.
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Affiliation(s)
- Leah Marie Roldan
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Thomas E Eggers
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Kevin L Kilgore
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA; MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH, 44109, USA; Louis Stokes VA Medical Center, 10701 East Boulevard, Cleveland, OH, 44106, USA
| | - Narendra Bhadra
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Tina Vrabec
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Niloy Bhadra
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA; MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH, 44109, USA.
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22
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Perra E, Rapeaux A, Nikolic K. The Crucial Role of Nerve Depolarisation in High Frequency Conduction Block in Mammalian Nerves: Simulation Study. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2018:2214-2217. [PMID: 30440845 DOI: 10.1109/embc.2018.8512759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neurostimulations which use High Frequency Alternating Current (HFAC) block show great promise for neuromodulatory therapies. Treatments have been developed for various health conditions including obesity and obesity related health risks, and now even stomach cancer treatments are being considered. However the mechanism of the block is still not completely clear, as well as how various neural and electrode parameters affect it. In order to study conduction block during HF stimulation in mammalian axons, we describe a detailed computational model and perform comprehensive simulations. We establish relationships between the blocking frequency and amplitude versus fibre diameter and the distance between the electrode and fibre. We found that only a certain level of depolarisation will universally create a block irrespective of the fibre size, and it is in the range 24-30mV depending on the stimulus frequency. Our study crucially improves our knowledge about this important technique which is rapidly emerging as a commercially available therapy.
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23
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Peh WYX, Raczkowska MN, Teh Y, Alam M, Thakor NV, Yen SC. Closed-loop stimulation of the pelvic nerve for optimal micturition. J Neural Eng 2018; 15:066009. [PMID: 30181427 DOI: 10.1088/1741-2552/aadee9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Neural stimulation to restore bladder function has traditionally relied on open-loop approaches that used pre-set parameters, which do not adapt to suboptimal outcomes. The goal of this study was to examine the effectiveness of a novel closed-loop stimulation paradigm for improving micturition or bladder voiding. APPROACH We compared the voiding efficiency obtained with this closed-loop framework against open-loop stimulation paradigms in anesthetized rats. The bladder pressures that preceded voiding, and the minimum current amplitudes for stimulating the pelvic nerves to evoke bladder contractions, were first calibrated for each animal. An automated closed-loop system was used to initiate voiding upon bladder fullness, adapt the stimulation current by using real-time bladder pressure changes to classify voiding outcomes, and halt stimulation when the bladder had been emptied or when the safe stimulation limit was reached. MAIN RESULTS In vivo testing demonstrated that the closed-loop system achieved high voiding efficiency or VE (75.7% ± 3.07%, mean ± standard error of the mean) and outperformed open-loop systems with either conserved number of stimulation epochs (63.2% ± 4.90% VE) or conserved charge injected (32.0% ± 1.70% VE). Post-hoc analyses suggest that the classification algorithm can be further improved with data from additional closed-loop experiments. SIGNIFICANCE This novel approach may be applied to an implantable device for treating underactive bladder (<60% VE), especially in cases where under- or over-stimulation of the nerve is a concern.
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Affiliation(s)
- Wendy Yen Xian Peh
- Singapore Institute for Neurotechnology, National University of Singapore, 28 Medical Drive, #05-02, Singapore 117456, Singapore
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Avendano-Coy J, Serrano-Munoz D, Taylor J, Goicoechea-Garcia C, Gomez-Soriano J. Peripheral Nerve Conduction Block by High-Frequency Alternating Currents: A Systematic Review. IEEE Trans Neural Syst Rehabil Eng 2018; 26:1131-1140. [DOI: 10.1109/tnsre.2018.2833141] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ghazavi A, Cogan SF. Electrochemical characterization of high frequency stimulation electrodes: role of electrode material and stimulation parameters on electrode polarization. J Neural Eng 2018; 15:036023. [DOI: 10.1088/1741-2552/aa9f31] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Peh WYX, Mogan R, Thow XY, Chua SM, Rusly A, Thakor NV, Yen SC. Novel Neurostimulation of Autonomic Pelvic Nerves Overcomes Bladder-Sphincter Dyssynergia. Front Neurosci 2018; 12:186. [PMID: 29618971 PMCID: PMC5871706 DOI: 10.3389/fnins.2018.00186] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 03/06/2018] [Indexed: 12/25/2022] Open
Abstract
The disruption of coordination between smooth muscle contraction in the bladder and the relaxation of the external urethral sphincter (EUS) striated muscle is a common issue in dysfunctional bladders. It is a significant challenge to overcome for neuromodulation approaches to restore bladder control. Bladder-sphincter dyssynergia leads to undesirably high bladder pressures, and poor voiding outcomes, which can pose life-threatening secondary complications. Mixed pelvic nerves are potential peripheral targets for stimulation to treat dysfunctional bladders, but typical electrical stimulation of pelvic nerves activates both the parasympathetic efferent pathway to excite the bladder, as well as the sensory afferent pathway that causes unwanted sphincter contractions. Thus, a novel pelvic nerve stimulation paradigm is required. In anesthetized female rats, we combined a low frequency (10 Hz) stimulation to evoke bladder contraction, and a more proximal 20 kHz stimulation of the pelvic nerve to block afferent activation, in order to produce micturition with reduced bladder-sphincter dyssynergia. Increasing the phase width of low frequency stimulation from 150 to 300 μs alone was able to improve voiding outcome significantly. However, low frequency stimulation of pelvic nerves alone evoked short latency (19.9–20.5 ms) dyssynergic EUS responses, which were abolished with a non-reversible proximal central pelvic nerve cut. We demonstrated that a proximal 20 kHz stimulation of pelvic nerves generated brief onset effects at lower current amplitudes, and was able to either partially or fully block the short latency EUS responses depending on the ratio of the blocking to stimulation current. Our results indicate that ratios >10 increased the efficacy of blocking EUS contractions. Importantly, we also demonstrated for the first time that this combined low and high frequency stimulation approach produced graded control of the bladder, while reversibly blocking afferent signals that elicited dyssynergic EUS contractions, thus improving voiding by 40.5 ± 12.3%. Our findings support advancing pelvic nerves as a suitable neuromodulation target for treating bladder dysfunction, and demonstrate the feasibility of an alternative method to non-reversible nerve transection and sub-optimal intermittent stimulation methods to reduce dyssynergia.
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Affiliation(s)
- Wendy Yen Xian Peh
- Singapore Institute for Neurotechnology, National University of Singapore, Singapore, Singapore
| | - Roshini Mogan
- Singapore Institute for Neurotechnology, National University of Singapore, Singapore, Singapore
| | - Xin Yuan Thow
- Singapore Institute for Neurotechnology, National University of Singapore, Singapore, Singapore
| | - Soo Min Chua
- Singapore Institute for Neurotechnology, National University of Singapore, Singapore, Singapore
| | - Astrid Rusly
- Singapore Institute for Neurotechnology, National University of Singapore, Singapore, Singapore
| | - Nitish V Thakor
- Singapore Institute for Neurotechnology, National University of Singapore, Singapore, Singapore.,Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore.,Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.,Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Shih-Cheng Yen
- Singapore Institute for Neurotechnology, National University of Singapore, Singapore, Singapore.,Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
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Bhadra N, Kilgore KL. Fundamentals of Kilohertz Frequency Alternating Current Nerve Conduction Block of the Peripheral Nervous System. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00010-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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28
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Prochazka A. Neurophysiology and neural engineering: a review. J Neurophysiol 2017; 118:1292-1309. [PMID: 28566462 PMCID: PMC5558026 DOI: 10.1152/jn.00149.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/30/2017] [Accepted: 05/30/2017] [Indexed: 12/19/2022] Open
Abstract
Neurophysiology is the branch of physiology concerned with understanding the function of neural systems. Neural engineering (also known as neuroengineering) is a discipline within biomedical engineering that uses engineering techniques to understand, repair, replace, enhance, or otherwise exploit the properties and functions of neural systems. In most cases neural engineering involves the development of an interface between electronic devices and living neural tissue. This review describes the origins of neural engineering, the explosive development of methods and devices commencing in the late 1950s, and the present-day devices that have resulted. The barriers to interfacing electronic devices with living neural tissues are many and varied, and consequently there have been numerous stops and starts along the way. Representative examples are discussed. None of this could have happened without a basic understanding of the relevant neurophysiology. I also consider examples of how neural engineering is repaying the debt to basic neurophysiology with new knowledge and insight.
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Affiliation(s)
- Arthur Prochazka
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
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Effect of Unmodulated 5-kHz Alternating Currents Versus Transcutaneous Electrical Nerve Stimulation on Mechanical and Thermal Pain, Tactile Threshold, and Peripheral Nerve Conduction: A Double-Blind, Placebo-Controlled Crossover Trial. Arch Phys Med Rehabil 2017; 98:888-895. [DOI: 10.1016/j.apmr.2016.11.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 11/14/2016] [Accepted: 11/17/2016] [Indexed: 11/21/2022]
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Yang G, Xiao Z, Wang J, Shen B, Roppolo JR, de Groat WC, Tai C. Post-stimulation block of frog sciatic nerve by high-frequency (kHz) biphasic stimulation. Med Biol Eng Comput 2016; 55:585-593. [PMID: 27370786 DOI: 10.1007/s11517-016-1539-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 06/24/2016] [Indexed: 10/21/2022]
Abstract
This study determined if high-frequency biphasic stimulation can induce nerve conduction block that persists after the stimulation is terminated, i.e., post-stimulation block. The frog sciatic nerve-muscle preparation was used in the study. Muscle contraction force induced by low-frequency (0.5 Hz) nerve stimulation was recorded to indicate the occurrence and recovery of nerve block induced by the high-frequency (5 or 10 kHz) biphasic stimulation. Nerve block was observed during high-frequency stimulation and after termination of the stimulation. The recovery from post-stimulation block occurred in two distinct phases. During the first phase, the complete block induced during high-frequency stimulation was maintained. The average maximal duration for the first phase was 107 ± 50 s. During the second phase, the block gradually or abruptly reversed. The duration of both first and second phases was dependent on stimulation intensity and duration but not frequency. Stimulation of higher intensity (1.4-2 times block threshold) and longer duration (5 min) produced the longest period (249 ± 58 s) for a complete recovery. Post-stimulation block can be induced by high-frequency biphasic stimulation, which is important for future investigations of the blocking mechanisms and for optimizing the stimulation parameters or protocols in clinical applications.
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Affiliation(s)
- Guangning Yang
- Department of Urology, University of Pittsburgh, 700 Kaufmann Building, Pittsburgh, PA, 15213, USA.,Department of Biomedical Engineering, Beijing Jiaotong University, Beijing, China
| | - Zhiying Xiao
- Department of Urology, University of Pittsburgh, 700 Kaufmann Building, Pittsburgh, PA, 15213, USA.,Department of Urology, The Second Hospital, Shandong University, Jinan, China
| | - Jicheng Wang
- Department of Urology, University of Pittsburgh, 700 Kaufmann Building, Pittsburgh, PA, 15213, USA
| | - Bing Shen
- Department of Urology, University of Pittsburgh, 700 Kaufmann Building, Pittsburgh, PA, 15213, USA
| | - James R Roppolo
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - William C de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Changfeng Tai
- Department of Urology, University of Pittsburgh, 700 Kaufmann Building, Pittsburgh, PA, 15213, USA. .,Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA.
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Zhang Z, Lyon TD, Kadow BT, Shen B, Wang J, Lee A, Kang A, Roppolo JR, de Groat WC, Tai C. Conduction block of mammalian myelinated nerve by local cooling to 15-30°C after a brief heating. J Neurophysiol 2016; 115:1436-45. [PMID: 26740534 DOI: 10.1152/jn.00954.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 01/05/2016] [Indexed: 11/22/2022] Open
Abstract
This study aimed at understanding thermal effects on nerve conduction and developing new methods to produce a reversible thermal block of axonal conduction in mammalian myelinated nerves. In 13 cats under α-chloralose anesthesia, conduction block of pudendal nerves (n = 20) by cooling (5-30°C) or heating (42-54°C) a small segment (9 mm) of the nerve was monitored by the urethral striated muscle contractions and increases in intraurethral pressure induced by intermittent (5 s on and 20 s off) electrical stimulation (50 Hz, 0.2 ms) of the nerve. Cold block was observed at 5-15°C while heat block occurred at 50-54°C. A complete cold block up to 10 min was fully reversible, but a complete heat block was only reversible when the heating duration was less than 1.3 ± 0.1 min. A brief (<1 min) reversible complete heat block at 50-54°C or 15 min of nonblock mild heating at 46-48°C significantly increased the cold block temperature to 15-30°C. The effect of heating on cold block fully reversed within ∼40 min. This study discovered a novel method to block mammalian myelinated nerves at 15-30°C, providing the possibility to develop an implantable device to block axonal conduction and treat many chronic disorders. The effect of heating on cold block is of considerable interest because it raises many basic scientific questions that may help reveal the mechanisms underlying cold or heat block of axonal conduction.
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Affiliation(s)
- Zhaocun Zhang
- Department of Urology, Qilu Hospital, Shandong University, Jinan, People's Republic of China; Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Timothy D Lyon
- Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Brian T Kadow
- Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Bing Shen
- Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Jicheng Wang
- Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Andy Lee
- Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Audry Kang
- Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - James R Roppolo
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - William C de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Changfeng Tai
- Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania; and Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
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Zhao S, Yang G, Wang J, Roppolo JR, de Groat WC, Tai C. Conduction block in myelinated axons induced by high-frequency (kHz) non-symmetric biphasic stimulation. Front Comput Neurosci 2015. [PMID: 26217217 PMCID: PMC4491630 DOI: 10.3389/fncom.2015.00086] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study used the Frankenhaeuser-Huxley axonal model to analyze the effects of non-symmetric waveforms on conduction block of myelinated axons induced by high-frequency (10-300 kHz) biphasic electrical stimulation. The results predict a monotonic relationship between block threshold and stimulation frequency for symmetric waveform and a non-monotonic relationship for non-symmetric waveforms. The symmetric waveform causes conduction block by constantly activating both sodium and potassium channels at frequencies of 20-300 kHz, while the non-symmetric waveforms share the same blocking mechanism from 20 kHz up to the peak threshold frequency. At the frequencies above the peak threshold frequency the non-symmetric waveforms block axonal conduction by either hyperpolarizing the membrane (if the positive pulse is longer) or depolarizing the membrane (if the negative pulse is longer). This simulation study further increases our understanding of conduction block in myelinated axons induced by high-frequency biphasic electrical stimulation, and can guide future animal experiments as well as optimize stimulation parameters that might be used for electrically induced nerve block in clinical applications.
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Affiliation(s)
- Shouguo Zhao
- Department of Urology, University of Pittsburgh Pittsburgh, PA, USA ; Department of Biomedical Engineering, Beijing Jiaotong University Beijing, China
| | - Guangning Yang
- Department of Urology, University of Pittsburgh Pittsburgh, PA, USA ; Department of Biomedical Engineering, Beijing Jiaotong University Beijing, China
| | - Jicheng Wang
- Department of Urology, University of Pittsburgh Pittsburgh, PA, USA
| | - James R Roppolo
- Department of Pharmacology and Chemical Biology, University of Pittsburgh Pittsburgh, PA, USA
| | - William C de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh Pittsburgh, PA, USA
| | - Changfeng Tai
- Department of Urology, University of Pittsburgh Pittsburgh, PA, USA ; Department of Pharmacology and Chemical Biology, University of Pittsburgh Pittsburgh, PA, USA
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McGee MJ, Amundsen CL, Grill WM. Electrical stimulation for the treatment of lower urinary tract dysfunction after spinal cord injury. J Spinal Cord Med 2015; 38:135-46. [PMID: 25582564 PMCID: PMC4397195 DOI: 10.1179/2045772314y.0000000299] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Electrical stimulation for bladder control is an alternative to traditional methods of treating neurogenic lower urinary tract dysfunction (NLUTD) resulting from spinal cord injury (SCI). In this review, we systematically discuss the neurophysiology of bladder dysfunction following SCI and the applications of electrical stimulation for bladder control following SCI, spanning from historic clinical approaches to recent pre-clinical studies that offer promising new strategies that may improve the feasibility and success of electrical stimulation therapy in patients with SCI. Electrical stimulation provides a unique opportunity to control bladder function by exploiting neural control mechanisms. Our understanding of the applications and limitations of electrical stimulation for bladder control has improved due to many pre-clinical studies performed in animals and translational clinical studies. Techniques that have emerged as possible opportunities to control bladder function include pudendal nerve stimulation and novel methods of stimulation, such as high frequency nerve block. Further development of novel applications of electrical stimulation will drive progress towards effective therapy for SCI. The optimal solution for restoration of bladder control may encompass a combination of efficient, targeted electrical stimulation, possibly at multiple locations, and pharmacological treatment to enhance symptom control.
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Affiliation(s)
- Meredith J. McGee
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | | | - Warren M. Grill
- Correspondence to: Warren M. Grill, Department of Biomedical Engineering, Duke University, 136 Hudson Hall, Box 90281, Durham, NC 27708-0281 USA.
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Fisher KM, Jillani NE, Oluoch GO, Baker SN. Blocking central pathways in the primate motor system using high-frequency sinusoidal current. J Neurophysiol 2014; 113:1670-80. [PMID: 25475345 PMCID: PMC4346720 DOI: 10.1152/jn.00347.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Electrical stimulation with high-frequency (2-10 kHz) sinusoidal currents has previously been shown to produce a transient and complete nerve block in the peripheral nervous system. Modeling and in vitro studies suggest that this is due to a prolonged local depolarization across a broad section of membrane underlying the blocking electrode. Previous work has used cuff electrodes wrapped around the peripheral nerve to deliver the blocking stimulus. We extended this technique to central motor pathways, using a single metal microelectrode to deliver focal sinusoidal currents to the corticospinal tract at the cervical spinal cord in anesthetized adult baboons. The extent of conduction block was assessed by stimulating a second electrode caudal to the blocking site and recording the antidromic field potential over contralateral primary motor cortex. The maximal block achieved was 99.6%, similar to findings of previous work in peripheral fibers, and the optimal frequency for blocking was 2 kHz. Block had a rapid onset, being complete as soon as the transient activation associated with the start of the sinusoidal current was over. High-frequency block was also successfully applied to the pyramidal tract at the medulla, ascending sensory pathways in the dorsal columns, and the descending systems of the medial longitudinal fasciculus. High-frequency sinusoidal stimulation produces transient, reversible lesions in specific target locations and therefore could be a useful alternative to permanent tissue transection in some experimental paradigms. It also could help to control or prevent some of the hyperactivity associated with chronic neurological disorders.
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Affiliation(s)
- Karen M Fisher
- Institute of Neuroscience, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom; and
| | - Ngalla E Jillani
- Institute of Primate Research, National Museums of Kenya, Karen, Nairobi, Kenya
| | - George O Oluoch
- Institute of Primate Research, National Museums of Kenya, Karen, Nairobi, Kenya
| | - Stuart N Baker
- Institute of Neuroscience, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom; and
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Zhao S, Yang G, Wang J, Roppolo JR, de Groat WC, Tai C. Effect of non-symmetric waveform on conduction block induced by high-frequency (kHz) biphasic stimulation in unmyelinated axon. J Comput Neurosci 2014; 37:377-86. [PMID: 24928360 DOI: 10.1007/s10827-014-0510-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Revised: 05/02/2014] [Accepted: 06/05/2014] [Indexed: 10/25/2022]
Abstract
The effect of a non-symmetric waveform on nerve conduction block induced by high-frequency biphasic stimulation is investigated using a lumped circuit model of the unmyelinated axon based on Hodgkin-Huxley equations. The simulation results reveal that the block threshold monotonically increases with the stimulation frequency for the symmetric stimulation waveform. However, a non-monotonic relationship between block threshold and stimulation frequency is observed when the stimulation waveform is non-symmetric. Constant activation of potassium channels by the high-frequency stimulation results in the increase of block threshold with increasing frequency. The non-symmetric waveform with a positive pulse 0.4-0.8 μs longer than the negative pulse blocks axonal conduction by hyperpolarizing the membrane and causes a decrease in block threshold as the frequency increases above 12-16 kHz. On the other hand, the non-symmetric waveform with a negative pulse 0.4-0.8 μs longer than the positive pulse blocks axonal conduction by depolarizing the membrane and causes a decrease in block threshold as the frequency increases above 40-53 kHz. This simulation study is important for understanding the potential mechanisms underlying the nerve block observed in animal studies, and may also help to design new animal experiments to further improve the nerve block method for clinical applications.
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Affiliation(s)
- Shouguo Zhao
- Department of Urology, University of Pittsburgh, 700 Kaufmann Building, 15213, Pittsburgh, PA, USA
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Utomo E, Groen J, Blok BFM. Surgical management of functional bladder outlet obstruction in adults with neurogenic bladder dysfunction. Cochrane Database Syst Rev 2014; 2014:CD004927. [PMID: 24859260 PMCID: PMC11162557 DOI: 10.1002/14651858.cd004927.pub4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND The most common type of functional bladder outlet obstruction in patients with neurogenic bladder is detrusor-sphincter dyssynergia (DSD). The lack of co-ordination between the bladder and the external urethral sphincter muscle (EUS) in DSD can result in poor bladder emptying and high bladder pressures, which may eventually lead to progressive renal damage. OBJECTIVES To assess the effectiveness of different surgical therapies for the treatment of functional bladder outlet obstruction (i.e. DSD) in adults with neurogenic bladder dysfunction. SEARCH METHODS We searched the Cochrane Incontinence Group Specialised Register, which contains trials identified from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE In-Process, and handsearching of journals and conference proceedings (searched 20 February 2014), and the reference lists of relevant articles. SELECTION CRITERIA Randomised controlled trials (RCTs) or quasi-RCTs comparing a surgical treatment of DSD in adults suffering from neurogenic bladder dysfunction, with no treatment, placebo, non-surgical treatment, or other surgical treatment, alone or in combination. DATA COLLECTION AND ANALYSIS Two review authors independently assessed trial quality and extracted data. MAIN RESULTS We included five trials (total of 199 participants, average age of 40 years). The neurological diseases causing DSD were traumatic spinal cord injury (SCI), multiple sclerosis (MS), or congenital malformations.One trial compared placement of sphincteric stent prosthesis with sphincterotomy. For urodynamic measurements, results for postvoid residual urine volume (PVR) and cystometric bladder capacity were inconclusive and consistent with benefit of either sphincteric stent prosthesis or sphincterotomy at three, six, 12, and 24 months. Results for maximum detrusor pressure (Pdet.max) were also inconclusive at three, six, and 12 months; however, after two years, the Pdet.max after sphincterotomy was lower than after stent placement (mean difference (MD) -30 cmH2O, 95% confidence interval (CI) 8.99 to 51.01).Four trials considered botulinum A toxin (BTX-A) injection in the EUS, either alone or in combination with other treatments. The comparators included oral baclofen, oral alpha blocker, lidocaine, and placebo. The BTX-A trials all differed in protocols, and therefore we did not undertake meta-analysis. A single 100 units transperineal BTX-A injection (Botox®) in patients with MS resulted in higher voided urine volumes (MD 69 mL, 95% CI 11.87 to 126.13), lower pre-micturition detrusor pressure (MD -10 cmH2O, 95% CI -17.62 to -2.38), and lower Pdet.max (MD -14 cmH2O, 95% CI -25.32 to -2.68) after 30 days, compared to placebo injection. Results for PVR using catheterisation, basal detrusor pressure, maximal bladder capacity, maximal urinary flow, bladder compliance at functional bladder capacity, maximal urethral pressure, and closure urethral pressure at 30 days were inconclusive and consistent with benefit of either BTX-A injection or placebo injections. In participants with SCI, treatment with 200 units of Chinese manufactured BTX-A injected at eight different sites resulted in better bladder compliance (MD 7.5 mL/cmH2O, 95% CI -10.74 to -4.26) than participants who received the same injections with the addition of oral baclofen. Results for maximum uroflow rate, maximal cystometric capacity, and volume per voiding were inconclusive and consistent with benefit of either BTX-A injection or BTX-A injection with the addition of oral baclofen. However, the poor quality of reporting in this trial caused us to question the relevance of bladder compliance as an adequate outcome measure.In participants with DSD due to traumatic SCI, MS, or congenital malformation, the results for PVRs after one day were inconclusive and consistent with benefit of either a single 100 units transperineal BTX-A (Botox®) injection or lidocaine injection. However, after seven and 30 days of BTX-A injection, PVRs were lower (MD -163 and -158 mL, 95% CI -308.65 to -17.35 and 95% CI -277.57 to -39.03, respectively) compared to participants who received lidocaine injections. Results at one month for Pdet.max on voiding, EUS activity in electromyography, and maximal urethral pressure were inconclusive and consistent with benefit of either BTX-A or lidocaine injections.Finally, one small trial consisting of five men with SCI compared weekly BTX-A injections with normal saline as placebo. The placebo had no effect on DSD in the two participants allocated to the placebo treatment. Their urodynamic parameters were unchanged from baseline values until subsequent injections with BTX-A once a week for three weeks. These subsequent injections resulted in similar responses to those of the three participants who were allocated to the BTX-A treatment. Unfortunately, the report presented no data on placebo treatment.Only the trial that compared sphincterotomy with stent placement reported outcome measures renal function and urologic complications related to DSD. Results for renal function at 12 and 24 months, and urologic complications related to DSD at three, six, 12, and 24 months were inconclusive and consistent with benefit of either sphincteric stent prosthesis or sphincterotomy.Adverse effects reported were haematuria due to the cystoscopic injection and muscle weakness, of which the latter may be related to the BTX-A dose used.All trials had some methodological shortcomings, so insufficient information was available to permit judgement of risk of bias. At least half of the trials had an unclear risk of selection bias and reporting bias. One trial had a high risk of attrition bias, and another trial had a high risk of reporting bias. AUTHORS' CONCLUSIONS Results from small studies with a high risk of bias have identified evidence of limited quality that intraurethral BTX-A injections improve some urodynamic measures after 30 days in the treatment of functional bladder outlet obstruction in adults with neurogenic bladder dysfunction. The necessity of reinjection of BTX-A is a significant drawback; a sphincterotomy might therefore be a more effective treatment option for lowering bladder pressure in the long-term.However, because of the limited availability of eligible trials, this review was unable to provide robust evidence in favour of any of the surgical treatment options. More RCTs are needed, measuring improvement on quality of life, and on other types of surgical treatment options for DSD since these are lacking. Future RCTs assessing the effectiveness of BTX-A injections also need to address the uncertainty about the optimal dose and mode of injection for this specific type of urological condition.
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Affiliation(s)
- Elaine Utomo
- Erasmus Medical CenterDepartment of UrologyRoom Na‐1708's‐Gravendijkwal 230RotterdamZuid‐HollandNetherlands3015 CE
| | - Jan Groen
- Erasmus Medical CenterDepartment of UrologyRoom Na‐1708's‐Gravendijkwal 230RotterdamZuid‐HollandNetherlands3015 CE
| | - Bertil FM Blok
- Erasmus Medical CenterDepartment of UrologyRoom Na‐1708's‐Gravendijkwal 230RotterdamZuid‐HollandNetherlands3015 CE
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Ommaya AK, Adams KM, Allman RM, Collins EG, Cooper RA, Dixon CE, Fishman PS, Henry JA, Kardon R, Kerns RD, Kupersmith J, Lo A, Macko R, McArdle R, McGlinchey RE, McNeil MR, O'Toole TP, Peckham PH, Tuszynski MH, Waxman SG, Wittenberg GF. Guest editorial: Opportunities in rehabilitation research. ACTA ACUST UNITED AC 2013; 50:vii-xxxii. [PMID: 24203548 DOI: 10.1682/jrrd.2012.09.0167] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Boger A, Bhadra N, Gustafson KJ. Different clinical electrodes achieve similar electrical nerve conduction block. J Neural Eng 2013; 10:056016. [PMID: 23986089 DOI: 10.1088/1741-2560/10/5/056016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE We aim to evaluate the suitability of four electrodes previously used in clinical experiments for peripheral nerve electrical block applications. APPROACH We evaluated peripheral nerve electrical block using three such clinical nerve cuff electrodes (the Huntington helix, the Case self-sizing Spiral and the flat interface nerve electrode) and one clinical intramuscular electrode (the Memberg electrode) in five cats. Amplitude thresholds for the block using 12 or 25 kHz voltage-controlled stimulation, onset response, and stimulation thresholds before and after block testing were determined. MAIN RESULTS Complete nerve block was achieved reliably and the onset response to blocking stimulation was similar for all electrodes. Amplitude thresholds for the block were lowest for the Case Spiral electrode (4 ± 1 Vpp) and lower for the nerve cuff electrodes (7 ± 3 Vpp) than for the intramuscular electrode (26 ± 10 Vpp). A minor elevation in stimulation threshold and reduction in stimulus-evoked urethral pressure was observed during testing, but the effect was temporary and did not vary between electrodes. SIGNIFICANCE Multiple clinical electrodes appear suitable for neuroprostheses using peripheral nerve electrical block. The freedom to choose electrodes based on secondary criteria such as ease of implantation or cost should ease translation of electrical nerve block to clinical practice.
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Affiliation(s)
- Adam Boger
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
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Kilgore KL, Bhadra N. Reversible nerve conduction block using kilohertz frequency alternating current. Neuromodulation 2013; 17:242-54; discussion 254-5. [PMID: 23924075 DOI: 10.1111/ner.12100] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 06/04/2013] [Accepted: 06/21/2013] [Indexed: 01/25/2023]
Abstract
OBJECTIVES The features and clinical applications of balanced-charge kilohertz frequency alternating currents (KHFAC) are reviewed. Preclinical studies of KHFAC block have demonstrated that it can produce an extremely rapid and reversible block of nerve conduction. Recent systematic analysis and experimentation utilizing KHFAC block have resulted in a significant increase in interest in KHFAC block, both scientifically and clinically. MATERIALS AND METHODS We review the history and characteristics of KHFAC block, the methods used to investigate this type of block, the experimental evaluation of block, and the electrical parameters and electrode designs needed to achieve successful block. We then analyze the existing clinical applications of high-frequency currents, comparing the early results with the known features of KHFAC block. RESULTS Although many features of KHFAC block have been characterized, there is still much that is unknown regarding the response of neural structures to rapidly fluctuating electrical fields. The clinical reports to date do not provide sufficient information to properly evaluate the mechanisms that result in successful or unsuccessful treatment. CONCLUSIONS KHFAC nerve block has significant potential as a means of controlling nerve activity for the purpose of treating disease. However, early clinical studies in the use of high-frequency currents for the treatment of pain have not been designed to elucidate mechanisms or allow direct comparisons to preclinical data. We strongly encourage the careful reporting of the parameters utilized in these clinical studies, as well as the development of outcome measures that could illuminate the mechanisms of this modality.
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Affiliation(s)
- Kevin L Kilgore
- Department of Orthopaedics, MetroHealth Medical Center, Cleveland, OH, USA; Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, USA; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
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Liu H, Zhu L, Sheng S, Sun L, Zhou H, Tang H, Qiu T. Post stimulus effects of high frequency biphasic electrical current on a fibre's conductibility in isolated frog nerves. J Neural Eng 2013; 10:036024. [PMID: 23676976 DOI: 10.1088/1741-2560/10/3/036024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVE High frequency biphasic (HFB) electrical currents are widely used in nerve blocking studies. Their safety margins largely remain unknown and need to be investigated. APPROACH This study, exploring the post stimulus effects of HFB electrical currents on a nerve's conductibility, was performed on bullfrog sciatic nerves. Both compound action potentials (CAPs) and differential CAPs (DCAPs, i.e. control CAPs subtracted by CAPs following HFB currents) were obtained, and N1 and N2 components, which were the first and second upward components of DCAPs, were used for analyses of the effects introduced by HFB electrical stimulation. MAIN RESULTS First, HFB currents of 10 kHz at a completely blocking threshold were applied for 5 s. The maximum amplitudes and conducting velocities of the CAPs were significantly (P < 0.02) decreased within the observed period (60 s) following HFB currents. The DCAPs displayed clear N1 and N2 components, demonstrating respectively the losses of the fibres' normal conductibility and the appearances of new delayed conductions. Decreases of N1 amplitudes along time, regarded as the recovery of the nerve's conductibility, exhibited two distinct phases: a fast one lasting several seconds and a slow one lasting longer than 5 min. Further tests showed a linear relationship between the HFB stimulation durations and recovering periods of N1 amplitudes. Supra-threshold blocking did not cause higher N1 amplitudes. SIGNIFICANCE This study indicates that HFB electrical currents lead to long lasting post stimulus reduction of a nerve's conductibility, which might relate to potential nerve injuries. A possible mechanism, focusing on changes in intracellular and periaxonal ionic concentrations, was proposed to underlie the reduction of the nerve's conductibility and potential nerve injuries. Greater caution and stimulation protocols with greater safety margins should be explored when utilizing HFB electrical current to block nerve conductions.
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Affiliation(s)
- Hailong Liu
- Department of Biomedical Engineering, Dalian University of Technology, Dalian, Liaoning, People's Republic of China.
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The Role of Biomaterials in Stimulating Bioelectrodes. Biomater Sci 2013. [DOI: 10.1016/b978-0-08-087780-8.00084-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Boger AS, Bhadra N, Gustafson KJ. High frequency sacral root nerve block allows bladder voiding. Neurourol Urodyn 2012; 31:677-82. [PMID: 22473837 DOI: 10.1002/nau.21075] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Accepted: 01/24/2011] [Indexed: 11/08/2022]
Abstract
AIMS Dyssynergic reflexive external urethral sphincter (EUS) activity following spinal cord injury can prevent bladder voiding, resulting in significant medical complications. Irreversible sphincterotomies or neurotomies can prevent EUS activation and allow bladder voiding, but may cause incontinence or loss of sacral reflexes. We investigated whether kilohertz frequency (KF) electrical conduction block of the sacral roots could prevent EUS activation and allow bladder voiding. METHODS The S2 sacral nerve roots were stimulated bilaterally to generate bladder pressure in six cats. One S1 nerve root was stimulated proximally (20 Hz biphasic pulse trains) to evoke EUS pressure, simulating worst-case dyssynergic EUS reflexes. KF waveforms (12.5 kHz biphasic square wave) applied to an electrode implanted distally on the S1 nerve root blocked nerve conduction, preventing the increase in EUS pressure and allowing voiding. RESULTS Applying KF waveforms increased bladder voiding in single, limited-duration trials from 3 ± 6% to 59 ± 12%. Voiding could be increased to 82 ± 9% of the initial bladder volume by repeating or increasing the duration of the trials. CONCLUSIONS Sacral nerve block can prevent EUS activation and allow complete bladder voiding, potentially eliminating the need for a neurotomy. Eliminating neurotomy requirements could increase patient acceptance of bladder voiding neuroprostheses, increasing patient quality of life and reducing the cost of patient care.
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Affiliation(s)
- Adam S Boger
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
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Ackermann DM, Bhadra N, Gerges M, Thomas PJ. Dynamics and sensitivity analysis of high-frequency conduction block. J Neural Eng 2011; 8:065007. [PMID: 22056338 PMCID: PMC3417344 DOI: 10.1088/1741-2560/8/6/065007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The local delivery of extracellular high-frequency stimulation (HFS) has been shown to be a fast acting and quickly reversible method of blocking neural conduction and is currently being pursued for several clinical indications. However, the mechanism for this type of nerve block remains unclear. In this study, we investigate two hypotheses: (1) depolarizing currents promote conduction block via inactivation of sodium channels and (2) the gating dynamics of the fast sodium channel are the primary determinate of minimal blocking frequency. Hypothesis 1 was investigated using a combined modeling and experimental study to investigate the effect of depolarizing and hyperpolarizing currents on high-frequency block. The results of the modeling study show that both depolarizing and hyperpolarizing currents play an important role in conduction block and that the conductance to each of three ionic currents increases relative to resting values during HFS. However, depolarizing currents were found to promote the blocking effect, and hyperpolarizing currents were found to diminish the blocking effect. Inward sodium currents were larger than the sum of the outward currents, resulting in a net depolarization of the nodal membrane. Our experimental results support these findings and closely match results from the equivalent modeling scenario: intra-peritoneal administration of the persistent sodium channel blocker ranolazine resulted in an increase in the amplitude of HFS required to produce conduction block in rats, confirming that depolarizing currents promote the conduction block phenomenon. Hypothesis 2 was investigated using a spectral analysis of the channel gating variables in a single-fiber axon model. The results of this study suggested a relationship between the dynamical properties of specific ion channel gating elements and the contributions of corresponding conductances to block onset. Specifically, we show that the dynamics of the fast sodium inactivation gate are too slow to track the high-frequency changes in membrane potential during HFS, and that the behavior of the fast sodium current was dominated by the low-frequency depolarization of the membrane. As a result, in the blocked state, only 5.4% of nodal sodium channels were found to be in the activatable state in the node closest to the blocking electrode, resulting in conduction block. Moreover, we find that the corner frequency for the persistent sodium channel activation gate corresponds to the frequency below which high-frequency stimuli of arbitrary amplitude are incapable of inducing conduction block.
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Affiliation(s)
| | - Niloy Bhadra
- Dept. of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- MetroHealth Medical Center, Cleveland, OH, USA
| | | | - Peter J. Thomas
- Depts. of Mathematics, Biology and Cognitive Science, Case Western Reserve University, Cleveland, OH, USA
- Dept. of Neuroscience, Oberlin College, Oberlin, OH, USA
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Waataja JJ, Tweden KS, Honda CN. Effects of high-frequency alternating current on axonal conduction through the vagus nerve. J Neural Eng 2011; 8:056013. [PMID: 21918293 DOI: 10.1088/1741-2560/8/5/056013] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
High-frequency alternating current (HFAC) is known to disrupt axonal conduction in peripheral nerves, and HFAC has much potential as a therapeutic approach for a number of pathological conditions. Many previous studies have utilized motor output as a bioassay of effects of HFAC on conduction through medium- to large-diameter motor axons. However, little is known about the effectiveness of HFAC on smaller, more slowly conducting nerve fibres. The present study tested whether HFAC influences axonal conduction through sub-diaphragmatic levels of the rat vagus nerve, which consists almost entirely of small calibre axons. Using an isolated nerve preparation, we tested the effects of HFAC on electrically evoked compound action potentials (CAPs). We found that delivery of charge-balanced HFAC at 5000 Hz for 1 min was effective in producing reversible blockade of axonal conduction. Both Aδ and C components of the vagus CAP were attenuated, and the degree of blockade as well as time to recovery was proportional to the amount of HFAC current delivered. The Aδ waves were more sensitive than C waves to HFAC blockade, but they required more time to recover.
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Ackermann DM, Ethier C, Foldes EL, Oby ER, Tyler D, Bauman M, Bhadra N, Miller L, Kilgore KL. Electrical conduction block in large nerves: high-frequency current delivery in the nonhuman primate. Muscle Nerve 2011; 43:897-9. [PMID: 21607972 PMCID: PMC3101373 DOI: 10.1002/mus.22037] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Recent studies have made significant progress toward the clinical implementation of high-frequency conduction block (HFB) of peripheral nerves. However, these studies were performed in small nerves, and questions remain regarding the nature of HFB in large-diameter nerves. This study in nonhuman primates shows reliable conduction block in large-diameter nerves (up to 4.1 mm) with relatively low-threshold current amplitude and only moderate nerve discharge prior to the onset of block.
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Affiliation(s)
- D Michael Ackermann
- Cleveland FES Center, Hamman 601, 2500 MetroHealth Drive, Cleveland, Ohio 44109, USA.
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Tai C, Guo D, Wang J, Roppolo JR, de Groat WC. Mechanism of conduction block in amphibian myelinated axon induced by biphasic electrical current at ultra-high frequency. J Comput Neurosci 2011; 31:615-23. [PMID: 21523417 DOI: 10.1007/s10827-011-0329-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 04/01/2011] [Accepted: 04/08/2011] [Indexed: 10/18/2022]
Abstract
The mechanism of axonal conduction block induced by ultra-high frequency (≥ 20 kHz) biphasic electrical current was investigated using a lumped circuit model of the amphibian myelinated axon based on Frankenhaeuser-Huxley (FH) equations. The ultra-high frequency stimulation produces constant activation of both sodium and potassium channels at the axonal node under the block electrode causing the axonal conduction block. This blocking mechanism is different from the mechanism when the stimulation frequency is between 4 kHz and 10 kHz, where only the potassium channel is constantly activated. The minimal stimulation intensity required to induce a conduction block increases as the stimulation frequency increases. The results from this simulation study are useful to guide future animal experiments to reveal the different mechanisms underlying nerve conduction block induced by high-frequency biphasic electrical current.
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Affiliation(s)
- Changfeng Tai
- Department of Urology, University of Pittsburgh, 700 Kaufmann Building, Pittsburgh, PA 15213, USA.
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Khedr EM, Alkady EAM, El-Hammady DH, Khalifa FAM, bin-Humam S. Repetitive Lumbosacral Nerve Magnetic Stimulation Improves Bladder Dysfunction Due to Lumbosacral Nerve Injury. Neurorehabil Neural Repair 2011; 25:570-6. [DOI: 10.1177/1545968311400091] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background. Rapid rate magnetic stimulation of human sacral nerve roots can reduce stress incontinence. Objective. To test stimulation for urgency incontinence due to lumbosacral plexopathy. Methods. The authors studied patients with intractable neurogenic urinary dysfunction due to lumbosacral nerve injuries. Eligible patients were randomized to receive either real or sham repetitive lumbosacral magnetic stimulation (rLMS; 15 Hz with a total of 1500 pulses/session) for 10 sessions. Evaluation was performed before starting treatment, immediately after the 5th and 10th treatment session, and 1 month later, using rating scales to score urinary dysfunction and a visual analogue scale (VAS) to assess lower back pain. Posterior tibial nerve F-wave and H-reflexes were tested before and after treatment. Results. Both treatment and control groups were comparable for baseline characters and sphincteric disturbances. The mean number of voids and incontinence per 24 hours was significantly reduced in patients who received rLMS. The improvement was maintained 1 month after the end of treatment. Patients receiving real-rLMS also reported an improvement in VAS ratings. Improvement in F-wave and H-reflex latencies after real stimulation ( P = .002 and P = .036, respectively) was found as well. Conclusion. rLMS at 15 Hz may improve urinary dysfunction secondary to lumbosacral nerve injury. Further trials can determine the profile of patients who may benefit and optimal stimulation parameters.
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Affiliation(s)
- Eman M. Khedr
- Department of Neurology, Faculty of Medicine, Assiut University Hospital, Assiut, Egypt
| | - Eman A. M. Alkady
- Rheumatology and Rehabilitation, Faculty of Medicine, Assiut University Hospital, Assiut, Egypt
| | - Dina H. El-Hammady
- Rheumatology and Rehabilitation, Faculty of Medicine, Assiut University Hospital, Assiut, Egypt
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Sanders PM, IJzerman MJ, Roach MJ, Gustafson KJ. Patient preferences for next generation neural prostheses to restore bladder function. Spinal Cord 2011; 49:113-9. [PMID: 20531360 PMCID: PMC4987090 DOI: 10.1038/sc.2010.65] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
STUDY DESIGN A survey administered to 66 individuals with spinal cord injury (SCI) implementing a choice-based conjoint (CBC) analysis. Six attributes with three levels each were defined and used to generate choice sets with treatment scenarios. Patients were asked to choose the scenario that they preferred most. OBJECTIVES To determine the utility weights for treatment characteristics as well as the overall preference for the three types of neural prostheses (NP), that is Brindley, rhizotomy-free Brindley, and pudendal nerve stimulation. Earlier studies have revealed the importance of restoration of bladder function, but no studies have been performed to determine the importance of NP features. SETTING Two academic affiliated medical systems' SCI outpatient and inpatient rehabilitation programs, Cleveland, OH. METHODS CBC analysis followed by multinomial logit modeling. Individual part-worth utilities were estimated using hierarchical Bayes. RESULTS Side effects had the greatest significant impact on subject choices, followed by the effectiveness on continence and voiding. NPs with rhizotomy-free sacral root stimulation were preferred (45% first choice) over pudendal afferent nerve stimulation (39% second choice) and sacral root stimulation with rhizotomy (53% third choice). Almost 20% did not want to have an NP at all times. CONCLUSION CBC has shown to be a valuable tool to support design choices. The data showed that persons would prefer a bladder NP with minimally invasive electrodes, which would give them complete bladder function, with no side effects and that can be operated by pushing a button and they do not have to recharge themselves.
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Affiliation(s)
- Patricia M.H. Sanders
- Department for Health Technology and Services Research. University of Twente, Enschede, NL
- Case Western Reserve University, Cleveland, OH, USA
| | - Maarten J. IJzerman
- Department for Health Technology and Services Research. University of Twente, Enschede, NL
- Case Western Reserve University, Cleveland, OH, USA
| | - Mary Joan Roach
- Case Western Reserve University, Cleveland, OH, USA
- MetroHealth Medical System, Department of PM&R and the Center for Health Research and Policy, Cleveland, OH, USA
| | - Kenneth J. Gustafson
- Case Western Reserve University, Cleveland, OH, USA
- Louis Stokes Cleveland VA Medical Center and the APT Center, Cleveland, OH, USA
- Cleveland FES Center Cleveland, OH, USA
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Ackermann DM, Bhadra N, Foldes EL, Wang XF, Kilgore KL. Effect of nerve cuff electrode geometry on onset response firing in high-frequency nerve conduction block. IEEE Trans Neural Syst Rehabil Eng 2010; 18:658-65. [PMID: 20813650 PMCID: PMC3467702 DOI: 10.1109/tnsre.2010.2071882] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The delivery of high-frequency alternating currents has been shown to produce a focal and reversible conduction block in whole nerve and is a potential therapeutic option for various diseases and disorders involving pathological or undesired neurological activity. However, delivery of high-frequency alternating current to a nerve produces a finite burst of neuronal firing, called the onset response, before the nerve is blocked. Reduction or elimination of the onset response is very important to moving this type of nerve block into clinical applications since the onset response is likely to result in undesired muscle contraction and pain. This paper describes a study of the effect of nerve cuff electrode geometry (specifically, bipolar contact separation distance), and waveform amplitude on the magnitude and duration of the onset response. Electrode geometry and waveform amplitude were both found to affect these measures. The magnitude and duration of the onset response showed a monotonic relationship with bipolar separation distance and amplitude. The duration of the onset response varied by as much as 820% on average for combinations of different electrode geometries and waveform amplitudes. Bipolar electrodes with a contact separation distance of 0.5 mm resulted in the briefest onset response on average. Furthermore, the data presented in this study provide some insight into a biophysical explanation for the onset response. These data suggest that the onset response consists of two different phases: one phase which is responsive to experimental variables such as electrode geometry and waveform amplitude, and one which is not and appears to be inherent to the transition to the blocked state. This study has implications for nerve block electrode and stimulation parameter selection for clinical therapy systems and basic neurophysiology studies.
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Affiliation(s)
- D Michael Ackermann
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
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