1
|
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.
Collapse
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
| |
Collapse
|
2
|
Goree JH, Grant SA, Dickerson DM, Ilfeld BM, Eshraghi Y, Vaid S, Valimahomed AK, Shah JR, Smith GL, Finneran JJ, Shah NN, Guirguis MN, Eckmann MS, Antony AB, Ohlendorf BJ, Gupta M, Gilbert JE, Wongsarnpigoon A, Boggs JW. Randomized Placebo-Controlled Trial of 60-Day Percutaneous Peripheral Nerve Stimulation Treatment Indicates Relief of Persistent Postoperative Pain, and Improved Function After Knee Replacement. Neuromodulation 2024:S1094-7159(24)00064-3. [PMID: 38739062 DOI: 10.1016/j.neurom.2024.03.001] [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: 12/26/2023] [Revised: 02/22/2024] [Accepted: 03/06/2024] [Indexed: 05/14/2024]
Abstract
OBJECTIVES Total knee arthroplasty (TKA) is an effective surgery for end-stage knee osteoarthritis, but chronic postoperative pain and reduced function affect up to 20% of patients who undergo such surgery. There are limited treatment options, but percutaneous peripheral nerve stimulation (PNS) is a promising nonopioid treatment option for chronic, persistent postoperative pain. The objective of the present study was to evaluate the effect of a 60-day percutaneous PNS treatment in a multicenter, randomized, double-blind, placebo-controlled trial for treating persistent postoperative pain after TKA. MATERIALS AND METHODS Patients with postoperative pain after knee replacement were screened for this postmarket, institutional review board-approved, prospectively registered (NCT04341948) trial. Subjects were randomized to receive either active PNS or placebo (sham) stimulation. Subjects and a designated evaluator were blinded to group assignments. Subjects in both groups underwent ultrasound-guided placement of percutaneous fine-wire coiled leads targeting the femoral and sciatic nerves on the leg with postoperative pain. Leads were indwelling for eight weeks, and the primary efficacy outcome compared the proportion of subjects in each group reporting ≥50% reduction in average pain relative to baseline during weeks five to eight. Functional outcomes (6-minute walk test; 6MWT and Western Ontario and McMaster Universities Osteoarthritis Index) and quality of life (Patient Global Impression of Change) also were evaluated at end of treatment (EOT). RESULTS A greater proportion of subjects in the PNS groups (60%; 12/20) than in the placebo (sham) group (24%; 5/21) responded with ≥50% pain relief relative to baseline (p = 0.028) during the primary endpoint (weeks 5-8). Subjects in the PNS group also walked a significantly greater distance at EOT than did those in the placebo (sham) group (6MWT; +47% vs -9% change from baseline; p = 0.048, n = 18 vs n = 20 completed the test, respectively). Prospective follow-up to 12 months is ongoing. CONCLUSIONS This study provides evidence that percutaneous PNS decreases persistent pain, which leads to improved functional outcomes after TKA at EOT.
Collapse
Affiliation(s)
- Johnathan H Goree
- Department of Anesthesiology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
| | - Stuart A Grant
- Department of Anesthesiology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - David M Dickerson
- Department of Anesthesiology, Critical Care, and Pain Medicine, Endeavor Health, Evanston, IL, USA; The University of Chicago, Pritzker School of Medicine, Chicago, IL, USA
| | - Brian M Ilfeld
- Department of Anesthesiology, University of California San Diego, La Jolla, CA, USA
| | - Yashar Eshraghi
- Department of Anesthesiology, Ochsner Medical Center, New Orleans, LA, USA
| | - Sandeep Vaid
- Better Health Clinical Research, Newnan, GA, USA
| | | | - Jarna R Shah
- Department of Anesthesiology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - G Lawson Smith
- Department of Anesthesiology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - John J Finneran
- Department of Anesthesiology, University of California San Diego, La Jolla, CA, USA
| | - Nirav N Shah
- Department of Anesthesiology, Critical Care, and Pain Medicine, Endeavor Health, Evanston, IL, USA; The University of Chicago, Pritzker School of Medicine, Chicago, IL, USA
| | - Maged N Guirguis
- Department of Anesthesiology, Ochsner Medical Center, New Orleans, LA, USA
| | - Maxim S Eckmann
- Department of Anesthesiology, University of Texas San Antonio, San Antonio, TX, USA
| | | | - Brian J Ohlendorf
- Department of Anesthesiology, Duke University Hospital, Durham, NC, USA
| | - Mayank Gupta
- Neuroscience Research Center, Overland Park, KS, USA
| | | | | | | |
Collapse
|
3
|
Dewald HA, Yao J, Dewald JPA, Nader A, Kirsch RF. Peripheral nerve blocks of wrist and finger flexors can increase hand opening in chronic hemiparetic stroke. Front Neurol 2024; 15:1284780. [PMID: 38456150 PMCID: PMC10919218 DOI: 10.3389/fneur.2024.1284780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 02/01/2024] [Indexed: 03/09/2024] Open
Abstract
Introduction Hand opening is reduced by abnormal wrist and finger flexor activity in many individuals with stroke. This flexor activity also limits hand opening produced by functional electrical stimulation (FES) of finger and wrist extensor muscles. Recent advances in electrical nerve block technologies have the potential to mitigate this abnormal flexor behavior, but the actual impact of nerve block on hand opening in stroke has not yet been investigated. Methods In this study, we applied the local anesthetic ropivacaine to the median and ulnar nerve to induce a complete motor block in 9 individuals with stroke and observed the impact of this block on hand opening as measured by hand pentagonal area. Volitional hand opening and FES-driven hand opening were measured, both while the arm was fully supported on a haptic table (Unloaded) and while lifting against gravity (Loaded). Linear mixed effect regression (LMER) modeling was used to determine the effect of Block. Results The ropivacaine block allowed increased hand opening, both volitional and FES-driven, and for both unloaded and loaded conditions. Notably, only the FES-driven and Loaded condition's improvement in hand opening with the block was statistically significant. Hand opening in the FES and Loaded condition improved following nerve block by nearly 20%. Conclusion Our results suggest that many individuals with stroke would see improved hand-opening with wrist and finger flexor activity curtailed by nerve block, especially when FES is used to drive the typically paretic finger and wrist extensor muscles. Such a nerve block (potentially produced by aforementioned emerging electrical nerve block technologies) could thus significantly address prior observed shortcomings of FES interventions for individuals with stroke.
Collapse
Affiliation(s)
- Hendrik A. Dewald
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Jun Yao
- Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, IL, United States
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States
| | - Julius P. A. Dewald
- Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, IL, United States
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States
| | - Antoun Nader
- Department of Anesthesiology, Northwestern University, Chicago, IL, United States
| | - Robert F. Kirsch
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Cleveland FES Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH, United States
| |
Collapse
|
4
|
Caussade T, Paduro E, Courdurier M, Cerpa E, Grill WM, Medina LE. Towards a more accurate quasi-static approximation of the electric potential for neurostimulation with kilohertz-frequency sources . J Neural Eng 2023; 20:10.1088/1741-2552/ad1612. [PMID: 38100821 PMCID: PMC10822676 DOI: 10.1088/1741-2552/ad1612] [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: 08/25/2023] [Accepted: 12/15/2023] [Indexed: 12/17/2023]
Abstract
Objective.Our goal was to determine the conditions for which a more precise calculation of the electric potential than the quasi-static approximation may be needed in models of electrical neurostimulation, particularly for signals with kilohertz-frequency components.Approach.We conducted a comprehensive quantitative study of the differences in nerve fiber activation and conduction block when using the quasi-static and Helmholtz approximations for the electric potential in a model of electrical neurostimulation.Main results.We first show that the potentials generated by sources of unbalanced pulses exhibit different transients as compared to those of charge-balanced pulses, and this is disregarded by the quasi-static assumption. Secondly, relative errors for current-distance curves were below 3%, while for strength-duration curves these ranged between 1%-17%, but could be improved to less than 3% across the range of pulse duration by providing a corrected quasi-static conductivity. Third, we extended our analysis to trains of pulses and reported a 'congruence area' below 700 Hz, where the fidelity of fiber responses is maximal for supra-threshold stimulation. Further examination of waveforms and polarities revealed similar fidelities in the congruence area, but significant differences were observed beyond this area. However, the spike-train distance revealed differences in activation patterns when comparing the response generated by each model. Finally, in simulations of conduction-block, we found that block thresholds exhibited errors above 20% for repetition rates above 10 kHz. Yet, employing a corrected value of the conductivity improved the agreement between models, with errors no greater than 8%.Significance.Our results emphasize that the quasi-static approximation cannot be naively extended to electrical stimulation with high-frequency components, and notable differences can be observed in activation patterns. As well, we introduce a methodology to obtain more precise model responses using the quasi-static approach, retaining its simplicity, which can be a valuable resource in computational neuroengineering.
Collapse
Affiliation(s)
- Thomas Caussade
- Instituto de Ingeniería Matemática y Computacional, Facultad de Matemáticas, Pontificia Universidad Católica de Chile, Santiago Chile
| | - Esteban Paduro
- Instituto de Ingeniería Matemática y Computacional, Facultad de Matemáticas, Pontificia Universidad Católica de Chile, Santiago Chile
| | - Matías Courdurier
- Departamento de Matemática, Facultad de Matemáticas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Eduardo Cerpa
- Instituto de Ingeniería Matemática y Computacional, Facultad de Matemáticas, Pontificia Universidad Católica de Chile, Santiago Chile
| | - Warren M. Grill
- Department of Biomedical Engineering, Department of Electrical and Computer Engineering, Department of Neurobiology, Department of Neurosurgery, Duke University, Durham, NC, USA
| | - Leonel E. Medina
- Departamento de Ingeniería Informática, Universidad de Santiago de Chile, Santiago, Chile
| |
Collapse
|
5
|
Bender SA, Green DB, Daniels RJ, Ganocy SP, Bhadra N, Vrabec TL. Effects on heart rate from direct current block of the stimulated rat vagus nerve. J Neural Eng 2023; 20:10.1088/1741-2552/acacc9. [PMID: 36535037 PMCID: PMC9972895 DOI: 10.1088/1741-2552/acacc9] [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: 08/24/2022] [Accepted: 12/19/2022] [Indexed: 12/23/2022]
Abstract
Objective.Although electrical vagus nerve stimulation has been shown to augment parasympathetic control of the heart, the effects of electrical conduction block have been less rigorously characterized. Previous experiments have demonstrated that direct current (DC) nerve block can be applied safely and effectively in the autonomic system, but additional information about the system dynamics need to be characterized to successfully deploy DC nerve block to clinical practice.Approach.The dynamics of the heart rate (HR) from DC nerve block of the vagus nerve were measured by stimulating the vagus nerve to lower the HR, and then applying DC block to restore normal rate. DC block achieved rapid, complete block, as well as partial block at lower amplitudes.Main Results. Complete block was also achieved using lower amplitudes, but with a slower induction time. The time for DC to induce complete block was significantly predicted by the amplitude; specifically, the amplitude expressed as a percentage of the current required for a rapid, 60 s induction time. Recovery times after the cessation of DC block could occur both instantly, and after a significant delay. Both blocking duration and injected charge were significant in predicting the delay in recovery to normal conduction.Significance. While these data show that broad features such as induction and recovery can be described well by the DC parameters, more precise features of the HR, such as the exact path of the induction and recoveries, are still undefined. These findings show promise for control of the cardiac autonomic nervous system, with potential to expand to the sympathetic inputs as well.
Collapse
Affiliation(s)
- Shane A. Bender
- Department of Physical Medicine and Rehabilitation, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.,Department of Physical Medicine and Rehabilitation, MetroHealth Medical Center, Cleveland, OH, USA
| | - David B. Green
- Department of Physical Medicine and Rehabilitation, MetroHealth Medical Center, Cleveland, OH, USA
| | - Robert J. Daniels
- Department of Physical Medicine and Rehabilitation, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.,Department of Physical Medicine and Rehabilitation, MetroHealth Medical Center, Cleveland, OH, USA
| | - Stephen P. Ganocy
- Department of Psychiatry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Niloy Bhadra
- Department of Physical Medicine and Rehabilitation, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.,Department of Physical Medicine and Rehabilitation, MetroHealth Medical Center, Cleveland, OH, USA
| | - Tina L. Vrabec
- Department of Physical Medicine and Rehabilitation, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.,Department of Physical Medicine and Rehabilitation, MetroHealth Medical Center, Cleveland, OH, USA
| |
Collapse
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
Maris S, Brands M, Lenskens D, Braeken G, Kemnitz S, Vanhove H, Mc Laughlin M, Meesen R, Brône B, Stessel B. Transcutaneous electrical nerve inhibition using medium frequency alternating current. Sci Rep 2022; 12:14911. [PMID: 36050354 PMCID: PMC9437086 DOI: 10.1038/s41598-022-18974-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 08/23/2022] [Indexed: 11/16/2022] Open
Abstract
Transcutaneous medium-frequency alternating electrical current is defined as an alternating current between 1 and 10 kHz and is capable of producing an instant, reversible block. This study aims to evaluate the efficacy of sensory perception and force production of the index and middle finger after transcutaneous medium-frequency alternating electrical current stimulation of the distal median nerve. A single-center prospective interventional cohort study was conducted in adult healthy volunteers at the Jessa Hospital, Hasselt, Belgium. Two different electrodes (PALS & 3M) were placed on the distal median nerve, which was located using a Sonosite X-Porte Ultrasound transducer, with the first electrode being placed on the skin at the level of the transverse carpal ligament and the second electrode 7 cm proximally to the first electrode. The tactile sensation was evaluated with Semmes–Weinstein monofilament test and sensation of pressure/pain was evaluated with an algometer. Peak force production was assessed with an electronic dynamometer. All measurements were performed at baseline and tMFAEC stimulation frequencies of 2 and 10 kHz in a randomized manner. Statistical analysis was performed with a one-way ANOVA with repeated measures test or a Friedman rank sum test, followed by the Wilcoxon signed rank test adjusted with Bonferroni correction. A p-value < 0.05 was considered statistically significant. From 9 to 13th of April 2021, 25 healthy volunteers were included in the Jessa Hospital, Hasselt, Belgium. A statistically significant reduction in tactile sensation during 2 kHz and 10 kHz stimulation compared to baseline was observed (2.89 ± 0.22 (PALS2); 3.35 ± 0.25 (3M2) and 2.14 ± 0.12 (PALS10); 2.38 ± 0.12 (3M10) versus − 1.75 ± 0.09 (baseline), p < 0.0001). 3M electrodes showed a tendency towards the elevation of pressure pain threshold compared to baseline. No significant difference in mean peak forces of the index and middle fingers after transcutaneous medium-frequency alternating electrical current stimulation with 2 and 10 kHz was found. This study demonstrates that transcutaneous medium-frequency alternating electrical current stimulation on the distal median nerve inhibits tactile sensory nerve activity in the index and middle finger when stimulation of 2 kHz and, to a lesser extent, 10 kHz was applied. A reduction of motor nerve activity was not observed but force production measurements may be prone to error. Trial registration: clinicaltrials.gov on 01/04/2021. NCT-Number: NCT04827173.
Collapse
Affiliation(s)
- Seppe Maris
- Department of Anaesthesiology and Pain Medicine, Jessa Hospital, Stadsomvaart 11, 3500, Hasselt, Belgium. .,Faculty of Medicine and Life Sciences, BIOMED Research Institute, UHasselt, Agoralaan Gebouw C, 3590, Diepenbeek, Belgium.
| | - Michiel Brands
- Department of Anaesthesiology and Pain Medicine, Jessa Hospital, Stadsomvaart 11, 3500, Hasselt, Belgium
| | - Daniele Lenskens
- Department of Anaesthesiology and Pain Medicine, Jessa Hospital, Stadsomvaart 11, 3500, Hasselt, Belgium.,Department of Anaesthesiology and Pain Medicine, University Hospital Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Geert Braeken
- Department of Anaesthesiology and Pain Medicine, Jessa Hospital, Stadsomvaart 11, 3500, Hasselt, Belgium
| | - Stefan Kemnitz
- Faculty of Medicine and Life Sciences, BIOMED Research Institute, UHasselt, Agoralaan Gebouw C, 3590, Diepenbeek, Belgium
| | - Herbert Vanhove
- Faculty of Medicine and Life Sciences, BIOMED Research Institute, UHasselt, Agoralaan Gebouw C, 3590, Diepenbeek, Belgium
| | - Myles Mc Laughlin
- Exp ORL, Department of Neurosciences, The Leuven Brain Institute, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Raf Meesen
- Neuroplasticity and Movement Control Research Group, Rehabilitation Research Institute (REVAL), Hasselt University, Agoralaan Gebouw A, 3590, Diepenbeek, Belgium.,Movement Control and Neuroplasticity Research Group, Group Biomedical Sciences, Department of Movement Sciences, KU Leuven, Herestraat 49, 3500, Leuven, Belgium
| | - Bert Brône
- Faculty of Medicine and Life Sciences, BIOMED Research Institute, UHasselt, Agoralaan Gebouw C, 3590, Diepenbeek, Belgium
| | - Björn Stessel
- Department of Anaesthesiology and Pain Medicine, Jessa Hospital, Stadsomvaart 11, 3500, Hasselt, Belgium.,Faculty of Medicine and Life Sciences, BIOMED Research Institute, UHasselt, Agoralaan Gebouw C, 3590, Diepenbeek, Belgium
| |
Collapse
|
8
|
Maeng WY, Tseng WL, Li S, Koo J, Hsueh YY. Electroceuticals for peripheral nerve regeneration. Biofabrication 2022; 14. [PMID: 35995036 PMCID: PMC10109522 DOI: 10.1088/1758-5090/ac8baa] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 08/22/2022] [Indexed: 11/12/2022]
Abstract
Electroceuticals provide promising opportunities for peripheral nerve regeneration, in terms of modulating the extensive endogenous tissue repair mechanisms between neural cell body, axons and target muscles. However, great challenges remain to deliver effective and controllable electroceuticals via bioelectronic implantable device. In this review, the modern fabrication methods of bioelectronic conduit for bridging critical nerve gaps after nerve injury are summarized, with regard to conductive materials and core manufacturing process. In addition, to deliver versatile electrical stimulation, the integration of implantable bioelectronic device is discussed, including wireless energy harvesters, actuators and sensors. Moreover, a comprehensive insight of beneficial mechanisms is presented, including up-to-date in vitro, in vivo and clinical evidence. By integrating conductive biomaterials, 3D engineering manufacturing process and bioelectronic platform to deliver versatile electroceuticals, the modern biofabrication enables comprehensive biomimetic therapies for neural tissue engineering and regeneration in the new era.
Collapse
Affiliation(s)
- Woo-Youl Maeng
- Bio-Medical Engineering, Korea University, B156, B, Hana Science Hall, 145, Anam-ro, Seongbuk-gu, Seoul, Seongbuk-gu, Seoul, 02841, Korea (the Republic of)
| | - Wan Ling Tseng
- Department of Surgery, National Cheng Kung University College of Medicine, No.138, Sheng-Li road, Tainan, 701, TAIWAN
| | - Song Li
- Department of Bioengineering, University of California Los Angeles, 5121 Eng V, Los Angeles, California, 90095, UNITED STATES
| | - Jahyun Koo
- Biomedical Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, 02841, Korea (the Republic of)
| | - Yuan-Yu Hsueh
- Department of Surgery, National Cheng Kung University College of Medicine, No.138, Sheng-Li road, Tainan, 701, TAIWAN
| |
Collapse
|
9
|
Rapeaux A, Constandinou TG. HFAC Dose Repetition and Accumulation Leads to Progressively Longer Block Carryover Effect in Rat Sciatic Nerve. Front Neurosci 2022; 16:852166. [PMID: 35712453 PMCID: PMC9197154 DOI: 10.3389/fnins.2022.852166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 05/04/2022] [Indexed: 11/13/2022] Open
Abstract
This paper describes high-frequency nerve block experiments carried out on rat sciatic nerves to measure the speed of recovery of A fibres from block carryover. Block carryover is the process by which nerve excitability remains suppressed temporarily after High Frequency Alternative (HFAC) block is turned off following its application. In this series of experiments 5 rat sciatic nerves were extracted and prepared for ex-vivo stimulation and recording in a specially designed perfusion chamber. For each nerve repeated HFAC block and concurrent stimulation trials were carried out to observe block carryover after signal shutoff. The nerve was allowed to recover fully between each trial. Time to recovery from block was measured by monitoring for when relative nerve activity returned to within 90% of baseline levels measured at the start of each trial. HFAC block carryover duration was found to be dependent on accumulated dose by statistical test for two different HFAC durations. The carryover property of HFAC block on A fibres could enable selective stimulation of autonomic nerve fibres such as C fibres for the duration of carryover. Block carryover is particularly relevant to potential chronic clinical applications of block as it reduces power requirements for stimulation to provide the blocking effect. This work characterizes this process toward the creation of a model describing its behavior.
Collapse
Affiliation(s)
- Adrien Rapeaux
- Next Generation Neural Interfaces Lab, Centre for Bioinspired Technology, Department of Electrical and Electronic Engineering, Imperial College London, London, United Kingdom.,Care Research and Technology Centre, UK Dementia Research Institute, London, United Kingdom
| | - Timothy G Constandinou
- Next Generation Neural Interfaces Lab, Centre for Bioinspired Technology, Department of Electrical and Electronic Engineering, Imperial College London, London, United Kingdom.,Care Research and Technology Centre, UK Dementia Research Institute, London, United Kingdom
| |
Collapse
|
10
|
Deletis V, Shils J, Anso J, Villar Ortega E, Marchal-Crespo L, Buetler KA, Raabe A, Seidel K. Effects of 10-kHz Subthreshold Stimulation on Human Peripheral Nerve Activation. Neuromodulation 2022; 26:614-619. [PMID: 35715282 DOI: 10.1016/j.neurom.2022.04.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 04/02/2022] [Accepted: 04/28/2022] [Indexed: 10/18/2022]
Abstract
OBJECTIVE The mechanisms of action of high-frequency stimulation (HFS) are unknown. We investigated the possible mechanism of subthreshold superexcitability of HFS on the excitability of the peripheral nerve. MATERIALS AND METHODS The ulnar nerve was stimulated at the wrist in six healthy participants with a single (control) stimulus, and the responses were compared with the responses to a continuous train of 5 seconds at frequencies of 500 Hz, 2.5 kHz, 5 kHz, and 10 kHz. Threshold intensity for compound muscle action potential (CMAP) was defined as intensity producing a 100-μV amplitude in ten sequential trials and "subthreshold" as 10% below the CMAP threshold. HFS threshold was defined as stimulation intensity eliciting visible tetanic contraction. RESULTS Comparing the threshold of single pulse stimulation for eliciting CMAP vs threshold for HFS response and pooling data at different frequencies (500 Hz-10 kHz) revealed a significant difference (p = 0.00015). This difference was most obvious at 10 kHz, with a mean value for threshold reduction of 42.2%. CONCLUSIONS HFS with a stimulation intensity below the threshold for a single pulse induces axonal superexcitability if applied in a train. It can activate the peripheral nerve and produce a tetanic muscle response. Subthreshold superexcitability may allow new insights into the mechanism of HFS.
Collapse
|
11
|
Muzquiz MI, Mintch L, Horn MR, Alhawwash A, Bashirullah R, Carr M, Schild JH, Yoshida K. A Reversible Low Frequency Alternating Current Nerve Conduction Block Applied to Mammalian Autonomic Nerves. SENSORS 2021; 21:s21134521. [PMID: 34282758 PMCID: PMC8271881 DOI: 10.3390/s21134521] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/23/2021] [Accepted: 06/28/2021] [Indexed: 11/30/2022]
Abstract
Electrical stimulation can be used to modulate activity within the nervous system in one of two modes: (1) Activation, where activity is added to the neural signalling pathways, or (2) Block, where activity in the nerve is reduced or eliminated. In principle, electrical nerve conduction block has many attractive properties compared to pharmaceutical or surgical interventions. These include reversibility, localization, and tunability for nerve caliber and type. However, methods to effect electrical nerve block are relatively new. Some methods can have associated drawbacks, such as the need for large currents, the production of irreversible chemical byproducts, and onset responses. These can lead to irreversible nerve damage or undesirable neural responses. In the present study we describe a novel low frequency alternating current blocking waveform (LFACb) and measure its efficacy to reversibly block the bradycardic effect elicited by vagal stimulation in anaesthetised rat model. The waveform is a sinusoidal, zero mean(charge balanced), current waveform presented at 1 Hz to bipolar electrodes. Standard pulse stimulation was delivered through Pt-Black coated PtIr bipolar hook electrodes to evoke bradycardia. The conditioning LFAC waveform was presented either through a set of CorTec® bipolar cuff electrodes with Amplicoat® coated Pt contacts, or a second set of Pt Black coated PtIr hook electrodes. The conditioning electrodes were placed caudal to the pulse stimulation hook electrodes. Block of bradycardic effect was assessed by quantifying changes in heart rate during the stimulation stages of LFAC alone, LFAC-and-vagal, and vagal alone. The LFAC achieved 86.2±11.1% and 84.3±4.6% block using hook (N = 7) and cuff (N = 5) electrodes, respectively, at current levels less than 110 µAp (current to peak). The potential across the LFAC delivering electrodes were continuously monitored to verify that the blocking effect was immediately reversed upon discontinuing the LFAC. Thus, LFACb produced a high degree of nerve block at current levels comparable to pulse stimulation amplitudes to activate nerves, resulting in a measurable functional change of a biomarker in the mammalian nervous system.
Collapse
Affiliation(s)
- M. Ivette Muzquiz
- Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA; (M.I.M.); (M.R.H.); (J.H.S.)
| | | | - M. Ryne Horn
- Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA; (M.I.M.); (M.R.H.); (J.H.S.)
| | - Awadh Alhawwash
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA;
- Biomedical Technology Department, King Saud University, Riyadh 11362, Saudi Arabia
| | - Rizwan Bashirullah
- Galvani Bioelectronics Inc., Collegeville, PA 19426, USA; (R.B.); (M.C.)
| | - Michael Carr
- Galvani Bioelectronics Inc., Collegeville, PA 19426, USA; (R.B.); (M.C.)
| | - John H. Schild
- Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA; (M.I.M.); (M.R.H.); (J.H.S.)
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA;
| | - Ken Yoshida
- Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA; (M.I.M.); (M.R.H.); (J.H.S.)
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA;
- Correspondence:
| |
Collapse
|
12
|
Muzquiz MI, Richardson L, Vetter C, Smolik M, Alhawwash A, Goodwill A, Bashirullah R, Carr M, Yoshida K. In-vivo application of low frequency alternating currents on porcine cervical vagus nerve evokes reversible nerve conduction block. Bioelectron Med 2021; 7:9. [PMID: 34187586 PMCID: PMC8243469 DOI: 10.1186/s42234-021-00072-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/03/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND This paper describes a method to reversibly block nerve conduction through direct application of a 1 Hz sinusoidal current waveform delivered through a bipolar nerve cuff electrode. This low frequency alternating current (LFAC) waveform was previously shown to reversibly block the effects of vagal pulse stimulation evoked bradycardia in-vivo in the anaesthetised rat model (Mintch et al. 2019). The present work measured the effectiveness of LFAC block on larger caliber myelinated vagal afferent fibers in human sized nerve bundles projecting to changes in breathing rate mediated by the Hering-Breuer (HB) reflex in anaesthetized domestic swine (n=5). METHODS Two bipolar cuff electrodes were implanted unilaterally to the left cervical vagus nerve, which was crushed caudal to the electrodes to eliminate cardiac effects. A tripolar recording cuff electrode was placed rostral to the bipolar stimulating electrodes on the same nerve to measure changes in the compound nerve action potentials (CNAP) elicited by the vagal pulse stimulation and conditioned by the LFAC waveform. Standard pulse stimulation was applied at a sufficient level to induce a reduction in breathing rate through the HB reflex. If unblocked, the HB reflex would cause breathing to slow down and potentially halt completely. Block was quantified by the ability of LFAC to reduce the effect of the HB reflex by monitoring the respiration rate during LFAC alone, LFAC and vagal stimulation, and vagal stimulation alone. RESULTS LFAC achieved 87.2 ±8.8% block (n=5) at current levels of 1.1 ±0.3 mAp (current to peak), which was well within the water window of the working electrode. CNAP showed changes that directly correlated to the effectiveness of LFAC block, which manifested itself as the slowing and amplitude reduction of components of the CNAP. CONCLUSION These novel findings suggest that LFAC is a potential alternative or complementary method to other electrical blocking techniques in clinical applications.
Collapse
Affiliation(s)
- Maria Ivette Muzquiz
- Department of Biomedical Engineering, Indiana University - Purdue University Indianapolis, Indianapolis, USA.
| | - Lindsay Richardson
- Department of Biomedical Engineering, Indiana University - Purdue University Indianapolis, Indianapolis, USA
| | - Christian Vetter
- Department of Biomedical Engineering, Indiana University - Purdue University Indianapolis, Indianapolis, USA
| | - Macallister Smolik
- Department of Biology, Indiana University - Purdue University Indianapolis, Indianapolis, USA
| | - Awadh Alhawwash
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, USA.,Biomedical Technology Department, King Saud University, Riyadh, Saudi Arabia
| | - Adam Goodwill
- Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, USA
| | | | - Michael Carr
- Galvani Bioelectronics, Glaxo Smith Kline, GSK, King of Prussia, USA
| | - Ken Yoshida
- Department of Biomedical Engineering, Indiana University - Purdue University Indianapolis, Indianapolis, USA.,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, USA
| |
Collapse
|
13
|
Bender SA, Green DB, Daniels RJ, Kilgore KL, Bhadra N, Vrabec TL. Fuzzy Logic Control of Heartrate by Electrical Block of Vagus Nerve. INTERNATIONAL IEEE/EMBS CONFERENCE ON NEURAL ENGINEERING : [PROCEEDINGS]. INTERNATIONAL IEEE EMBS CONFERENCE ON NEURAL ENGINEERING 2021; 2021:1083-1086. [PMID: 34909125 PMCID: PMC8667196 DOI: 10.1109/ner49283.2021.9441092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Although vagus nerve stimulation (VNS) can be used to reduce heartrate by enhancing parasympathetic activity, a fully controllable intervention would also require a method for downregulating parasympathetic activity. A direct current (DC) block can be applied to a nerve to block its action potential conduction. This nerve block can be used to downregulate parasympathetic activity by blocking afferent reflexes. The damaging effects of reactions that occur at the electrode-nerve interface using conventional platinum electrodes can be avoided by separating the electrode from the nerve. Using a biocompatible, ionically conducting medium, the electrode and the damaging reactions can be isolated in a vessel away from the nerve. This type of electrode has been called the Separated Interface Nerve Electrode (SINE). Fuzzy logic control (FLC) is a controller approach that is well suited to physiological systems. The SINE, controlled by an FLC, was utilized to block a stimulated vagus nerve and regulate heart rate. The FLC was able to maintain the heartrate at a pre-determined setpoint while still achieving instant recovery when the block was removed.
Collapse
Affiliation(s)
- Shane A Bender
- Case Western Reserve University 10900 Euclid Ave., Cleveland, Ohio, 44106
| | - David B Green
- Case Western Reserve University 10900 Euclid Ave., Cleveland, Ohio, 44106
| | - Robert J Daniels
- Case Western Reserve University 10900 Euclid Ave., Cleveland, Ohio, 44106
| | - Kevin L Kilgore
- Case Western Reserve University 10900 Euclid Ave., Cleveland, Ohio, 44106
| | - Niloy Bhadra
- MetroHealth Medical Center 2500 MetroHealth Dr Cleveland, OH, 44109
| | - Tina L Vrabec
- MetroHealth Medical Center 2500 MetroHealth Dr Cleveland, OH 44109
| |
Collapse
|
14
|
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: 28] [Impact Index Per Article: 9.3] [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.
Collapse
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.
| |
Collapse
|
15
|
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.
Collapse
|
16
|
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.
Collapse
Affiliation(s)
- Edgar Peña
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
| | | | | |
Collapse
|
17
|
Kilohertz waveforms optimized to produce closed-state Na+ channel inactivation eliminate onset response in nerve conduction block. PLoS Comput Biol 2020; 16:e1007766. [PMID: 32542050 PMCID: PMC7316353 DOI: 10.1371/journal.pcbi.1007766] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 06/25/2020] [Accepted: 03/02/2020] [Indexed: 02/01/2023] Open
Abstract
The delivery of kilohertz frequency alternating current (KHFAC) generates rapid, controlled, and reversible conduction block in motor, sensory, and autonomic nerves, but causes transient activation of action potentials at the onset of the blocking current. We implemented a novel engineering optimization approach to design blocking waveforms that eliminated the onset response by moving voltage-gated Na+ channels (VGSCs) to closed-state inactivation (CSI) without first opening. We used computational models and particle swarm optimization (PSO) to design a charge-balanced 10 kHz biphasic current waveform that produced conduction block without onset firing in peripheral axons at specific locations and with specific diameters. The results indicate that it is possible to achieve onset-free KHFAC nerve block by causing CSI of VGSCs. Our novel approach for designing blocking waveforms and the resulting waveform may have utility in clinical applications of conduction block of peripheral nerve hyperactivity, for example in pain and spasticity. Many neurological disorders, including pain and spasticity, are characterized by undesirable increases in sensory, motor, or autonomic nerve activity. Local application of kilohertz frequency alternating currents (KHFAC) can effectively and completely block the conduction of undesired hyperactivity through peripheral nerves and could be a therapeutic approach for alleviating disease symptoms. However, KHFAC nerve block produces an undesirable initial burst of action potentials prior to achieving block. This onset firing may result in muscle contraction and pain and is a significant impediment to potential clinical applications of KHFAC nerve block. We present a novel engineering optimization approach for designing a blocking waveform that completely eliminated the onset firing in peripheral axons by moving voltage-gated Na+ channels to closed-state inactivation. Our results suggest that the resulting KHFAC waveform can generate electric nerve block without an onset response. Our approach for optimizing blocking waveforms represents a novel engineering design methodology with myriad potential applications and has relevance for the conduction block of peripheral nerve hyperactivity.
Collapse
|
18
|
Ford JB, Ganguly M, Poorman ME, Grissom WA, Jenkins MW, Chiel HJ, Jansen ED. Identifying the Role of Block Length in Neural Heat Block to Reduce Temperatures During Infrared Neural Inhibition. Lasers Surg Med 2020; 52:259-275. [PMID: 31347188 PMCID: PMC6981060 DOI: 10.1002/lsm.23139] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2019] [Indexed: 01/01/2023]
Abstract
BACKGROUND AND OBJECTIVES The objective of this study is to assess the hypothesis that the length of axon heated, defined here as block length (BL), affects the temperature required for thermal inhibition of action potential propagation applied using laser heating. The presence of such a phenomenon has implications for how this technique, called infrared neural inhibition (INI), may be applied in a clinically safe manner since it suggests that temperatures required for therapy may be reduced through the proper spatial application of light. Here, we validate the presence of this phenomenon by assessing how the peak temperatures during INI are reduced when two different BLs are applied using irradiation from either one or two adjacent optical fibers. STUDY DESIGN/MATERIALS AND METHODS Assessment of the role of BL was carried out over two phases. First, a computational proof of concept was performed in the neural conduction simulation environment, NEURON, simulating the response of action potentials to increased temperatures applied at different full-width at half-maxima (FWHM) along axons. Second, ex vivo validation of these predictions was performed by measuring the radiant exposure, peak temperature rise, and FWHM of heat distributions associated with INI from one or two adjacent optical fibers. Electrophysiological assessment of radiant exposures at inhibition threshold were carried out in ex vivo Aplysia californica (sea slug) pleural abdominal nerves ( n = 6), an invertebrate with unmyelinated axons. Measurement of the maximum temperature rise required for induced heat block was performed in a water bath using a fine wire thermocouple. Finally, magnetic resonance thermometry (MRT) was performed on a nerve immersed in saline to assess the elevated temperature distribution at these radiant exposures. RESULTS Computational modeling in NEURON provided a theoretical proof of concept that the BL is an important factor contributing to the peak temperature required during neural heat block, predicting a 11.7% reduction in temperature rise when the FWHM along an axon is increased by 42.9%. Experimental validation showed that, when using two adjacent fibers instead of one, a 38.5 ± 2.2% (mean ± standard error of the mean) reduction in radiant exposure per pulse per fiber threshold at the fiber output (P = 7.3E-6) is measured, resulting in a reduction in peak temperature rise under each fiber of 23.5 ± 2.1% ( P = 9.3E-5) and 15.0 ± 2.4% ( P = 1.4E-3) and an increase in the FWHM of heating by 37.7 ± 6.4% ( P = 1E-3), 68.4 ± 5.2% ( P = 2.4E-5), and 51.9 ± 9.9% ( P = 1.7E-3) in three MRT slices. CONCLUSIONS This study provides the first experimental evidence for a phenomenon during the heat block in which the temperature for inhibition is dependent on the BL. While more work is needed to further reduce the temperature during INI, the results highlight that spatial application of the temperature rise during INI must be considered. Optimized implementation of INI may leverage this cellular response to provide optical modulation of neural signals with lower temperatures over greater time periods, which may increase the utility of the technique for laboratory and clinical use. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Jeremy B. Ford
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, Tennessee 37232
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, Tennessee 37232
| | - Mohit Ganguly
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, Tennessee 37232
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, Tennessee 37232
| | - Megan E. Poorman
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, Tennessee 37232
- Vanderbilt University Institute of Imaging Sciences, Vanderbilt University, 1161 21st Ave S, Nashville, Tennessee 37232
| | - William A. Grissom
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, Tennessee 37232
- Vanderbilt University Institute of Imaging Sciences, Vanderbilt University, 1161 21st Ave S, Nashville, Tennessee 37232
| | - Michael W. Jenkins
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, Ohio 44106
- Department of Pediatrics, Case Western Reserve University, 2109 Adelbert Rd, Cleveland, Ohio 44106
| | - Hillel J. Chiel
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, Ohio 44106
- Department of Biology, Case Western Reserve University, 2080 Adelbert Rd, Cleveland, Ohio 44106
- Department of Neurosciences, Case Western Reserve University, 2210 Circle Drive, Cleveland, Ohio 44106
| | - E. Duco Jansen
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, Tennessee 37232
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Nashville, Tennessee 37232
- Department of Neurological Surgery, Vanderbilt University, 1161 21st Ave S, Nashville, Tennessee 37232
| |
Collapse
|
19
|
Finch P, Price L, Drummond P. High-Frequency (10 kHz) Electrical Stimulation of Peripheral Nerves for Treating Chronic Pain: A Double-Blind Trial of Presence vs Absence of Stimulation. Neuromodulation 2018; 22:529-536. [PMID: 30444276 DOI: 10.1111/ner.12877] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 08/29/2018] [Accepted: 09/16/2018] [Indexed: 12/12/2022]
Abstract
OBJECTIVES The study objectives were to perform a clinical audit of patients implanted with 10 kHz spinal cord (SCS) and peripheral nerve (PNS) stimulators for treating chronic pain and to investigate the effect of 10 kHz PNS on pain and other sensory modalities in a double-blind cross-over trial. METHODS Pain, disability, and medication status were audited for 12 months after stimulator implantation in 58 SCS patients and in 11 PNS patients with an electrode positioned along a branch of the occipital or trigeminal nerve (four patients), a limb nerve trunk (four patients), or the S1 nerve root, genito-femoral nerve or ileo-inguinal nerve (one patient each). In PNS patients, pain and other sensory modalities were also assessed double-blind before and after the stimulator was switched either ON or OFF for two hours (protocol 1) or four hours (protocol 2). RESULTS Decreases in pain and disability after stimulator implantation were maintained in both groups at 3-6 months, but these decreases were greater in PNS than SCS patients. In PNS trial patients, pain increased after the system had been turned OFF overnight for at least 12 hours before testing. Pain did not change after two hours of PNS but had decreased significantly after four hours. Other sensory modalities were minimally affected either by two or four hours of stimulation. CONCLUSIONS These findings suggest that PNS at 10 kHz decreases pain when conducted for at least four hours. Stimulation analgesia does not appear to be due to sensory conduction block.
Collapse
Affiliation(s)
- Philip Finch
- Perth Pain Management Centre, Perth, Western Australia, Australia
| | - Leanne Price
- Perth Pain Management Centre, Perth, Western Australia, Australia
| | - Peter Drummond
- School of Psychology and Exercise Science, Murdoch University, Perth, Western Australia, Australia
| |
Collapse
|