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Buchwalder S, Hersberger M, Rebl H, Seemann S, Kram W, Hogg A, Tvedt LGW, Clausen I, Burger J. An Evaluation of Parylene Thin Films to Prevent Encrustation for a Urinary Bladder Pressure MEMS Sensor System. Polymers (Basel) 2023; 15:3559. [PMID: 37688185 PMCID: PMC10490164 DOI: 10.3390/polym15173559] [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: 07/31/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 09/10/2023] Open
Abstract
Recent developments in urological implants have focused on preventive strategies to mitigate encrustation and biofilm formation. Parylene, a conformal, pinhole-free polymer coating, has gained attention due to its high biocompatibility and chemical resistance, excellent barrier properties, and low friction coefficient. This study aims to evaluate the effectiveness of parylene C in comparison to a parylene VT4 grade coating in preventing encrustation on a urinary bladder pressure MEMS sensor system. Additionally, silicon oxide (SiOx) applied as a finish coating was investigated for further improvements. An in vitro encrustation system mimicking natural urine flow was used to quantify the formation of urinary stones. These stones were subsequently analyzed using Fourier transform infrared spectrometry (FTIR). Encrustation results were then discussed in relation to coating surface chemical properties. Parylene C and VT4 grades demonstrated a very low encrustation mass, making them attractive options for encrustation prevention. The best performance was achieved after the addition of a hydrophilic SiOx finish coating on parylene VT4 grade. Parylene-based encapsulation proved to be an outstanding solution to prevent encrustation for urological implants.
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Affiliation(s)
- Sébastien Buchwalder
- School of Biomedical and Precision Engineering, University of Bern, Güterstrasse 24/26, 3010 Bern, Switzerland; (M.H.); (J.B.)
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Mittelstrasse 43, 3012 Bern, Switzerland
| | - Mario Hersberger
- School of Biomedical and Precision Engineering, University of Bern, Güterstrasse 24/26, 3010 Bern, Switzerland; (M.H.); (J.B.)
| | - Henrike Rebl
- Institute for Cell Biology, Rostock University Medical Center, Schillingallee 69, 18057 Rostock, Germany; (H.R.); (S.S.)
| | - Susanne Seemann
- Institute for Cell Biology, Rostock University Medical Center, Schillingallee 69, 18057 Rostock, Germany; (H.R.); (S.S.)
| | - Wolfgang Kram
- Department of Urology, Rostock University Medical Center, Schillingallee 35, 18057 Rostock, Germany;
| | - Andreas Hogg
- Coat-X SA, Eplatures-Grise 17, 2300 La Chaux-de-Fonds, Switzerland;
| | - Lars G. W. Tvedt
- InVivo Bionics AS, Gaustadallèen 21, 0349 Oslo, Norway; (L.G.W.T.); (I.C.)
| | - Ingelin Clausen
- InVivo Bionics AS, Gaustadallèen 21, 0349 Oslo, Norway; (L.G.W.T.); (I.C.)
| | - Jürgen Burger
- School of Biomedical and Precision Engineering, University of Bern, Güterstrasse 24/26, 3010 Bern, Switzerland; (M.H.); (J.B.)
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Ojha R, Singh A, George J, Chandy BR. Neuromodulation of spinal reflex pathway for the treatment of detrusor overactivity by medial plantar nerve stimulation at surface of sole of foot in patients with spinal cord injury. J Neurosci Rural Pract 2023; 14:495-500. [PMID: 37692814 PMCID: PMC10483192 DOI: 10.25259/jnrp_27_2023] [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: 01/12/2023] [Accepted: 07/08/2023] [Indexed: 09/12/2023] Open
Abstract
Objectives Suprasacral spinal cord lesions are prone to have neurogenic detrusor overactivity leading to urinary incontinence. Current medical management has known side-effects and often surgical managements are irreversible. Electrical stimulation to modulate spinal reflex pathway having same nerve root as urinary bladder is reported in the literature. This study aimed to reduce detrusor overactivity in patients with spinal cord injury (SCI) using surface electrical stimulation of medial plantar nerve at the sole of foot. Materials and Methods Twenty adults with SCI having episode of at least 1 leak/day due to detrusor overactivity as diagnosed by cystometrogram (CMG), were on clean intermittent catheterization and ankle jerk was present consented for the study. Participants were asked to maintain bladder diary a week before and during 2 weeks of treatment. CMG was done on day-0 and day-14. cmcUroModul@tor®, an inhouse developed electrical stimulator was used for ½ h daily for period of 2 weeks. Patient satisfaction feedback questionnaire was taken on completion of treatment. CMG data were analyzed using Wilcoxon signed-ranked test while bladder diary was analyzed using binomial distribution. P < 0.05 was considered as statistically significant. Institutional Review Board (IRB) and ethics committee of Christian Medical College, Vellore, approved the study (CMC/IRB/11061). Results Statistical significant improvement in maximum detrusor pressure (P = 0.03) and cystometric capacity (P = 0.04) was observed. Of 20 subjects, 18 showed improvement in bladder diary. Conclusion Neuromodulation of medial plantar nerve at sole of foot by surface electrical stimulation is non-invasive, cost-effective, and alternative simple treatment modality for urinary incontinence due to detrusor overactivity.
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Affiliation(s)
- Rajdeep Ojha
- Center for Advanced Technology Enabled Rehabilitation (CATER), Department of Physical Medicine and Rehabilitation, Christian Medical College, Vellore, Tamil Nadu, India
| | - Abhinav Singh
- Department of Physical Medicine and Rehabilitation, Indira Gandhi Institute of Medical Sciences, Patna, Bihar, India
| | - Jacob George
- Department of Physical Medicine and Rehabilitation, Christian Medical College, Vellore Tamil Nadu, India
| | - Bobeena Rachel Chandy
- Department of Physical Medicine and Rehabilitation, Christian Medical College, Vellore Tamil Nadu, India
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Morse LR, Field-Fote EC, Contreras-Vidal J, Noble-Haeusslein LJ, Rodreick M, Shields RK, Sofroniew M, Wudlick R, Zanca JM. Meeting Proceedings for SCI 2020: Launching a Decade of Disruption in Spinal Cord Injury Research. J Neurotrauma 2021; 38:1251-1266. [PMID: 33353467 DOI: 10.1089/neu.2020.7174] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The spinal cord injury (SCI) research community has experienced great advances in discovery research, technology development, and promising clinical interventions in the past decade. To build upon these advances and maximize the benefit to persons with SCI, the National Institutes of Health (NIH) hosted a conference February 12-13, 2019 titled "SCI 2020: Launching a Decade of Disruption in Spinal Cord Injury Research." The purpose of the conference was to bring together a broad range of stakeholders, including researchers, clinicians and healthcare professionals, persons with SCI, industry partners, regulators, and funding agency representatives to break down existing communication silos. Invited speakers were asked to summarize the state of the science, assess areas of technological and community readiness, and build collaborations that could change the trajectory of research and clinical options for people with SCI. In this report, we summarize the state of the science in each of five key domains and identify the gaps in the scientific literature that need to be addressed to move the field forward.
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Affiliation(s)
- Leslie R Morse
- Department of Rehabilitation Medicine, University of Minnesota School of Medicine, Minneapolis, Minnesota, USA
| | - Edelle C Field-Fote
- Shepherd Center, Atlanta, Georgia, USA.,Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jose Contreras-Vidal
- Laboratory for Non-Invasive Brain Machine Interfaces, NSF IUCRC BRAIN, Cullen College of Engineering, University of Houston, Houston, Texas, USA
| | - Linda J Noble-Haeusslein
- Departments of Neurology and Psychology and the Institute of Neuroscience, University of Texas at Austin, Austin, Texas, USA
| | | | - Richard K Shields
- Department of Physical Therapy and Rehabilitation Science, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Michael Sofroniew
- Department of Neurobiology, University of California, Los Angeles, California, USA
| | - Robert Wudlick
- Department of Rehabilitation Medicine, University of Minnesota School of Medicine, Minneapolis, Minnesota, USA
| | - Jeanne M Zanca
- Spinal Cord Injury Research, Kessler Foundation, West Orange, New Jersey, USA.,Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, New Jersey, USA
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Pikov V, McCreery DB, Han M. Intraspinal stimulation with a silicon-based 3D chronic microelectrode array for bladder voiding in cats. J Neural Eng 2020; 17. [PMID: 33181490 PMCID: PMC8113353 DOI: 10.1088/1741-2552/abca13] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 11/12/2020] [Indexed: 12/31/2022]
Abstract
Objective. Bladder dysfunction is a significant and largely unaddressed problem for people living with spinal cord injury (SCI). Intermittent catheterization does not provide volitional control of micturition and has numerous side effects. Targeted electrical microstimulation of the spinal cord has been previously explored for restoring such volitional control in the animal model of experimental SCI. Here, we continue the development of the intraspinal microstimulation array technology to evaluate its ability to provide more focused and reliable bladder control in the feline animal model. Approach. For the first time, a mechanically robust intraspinal multisite silicon array was built using novel microfabrication processes to provide custom-designed tip geometry and 3D electrode distribution. Long-term implantation was performed in eight spinally intact animals for a period up to 6 months, targeting the dorsal gray commissure area in the S2 sacral cord that is known to be involved in the coordination between the bladder detrusor and the external urethral sphincter. Main results. About one third of the electrode sites in the that area produced micturition-related responses. The effectiveness of stimulation was further evaluated in one of eight animals after spinal cord transection (SCT). We observed increased bladder responsiveness to stimulation starting at 1 month post-transection, possibly due to supraspinal disinhibition of the spinal circuitry and/or hypertrophy and hyperexcitability of the spinal bladder afferents. Significance. 3D intraspinal microstimulation arrays can be chronically implanted and provide a beneficial effect on the bladder voiding in the intact spinal cord and after SCT. However, further studies are required to assess longer-term reliability and safety of the developed intraspinal microstimulation array prior to eventual human translation.
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Affiliation(s)
- Victor Pikov
- Medipace Inc, Pasadena, California, UNITED STATES
| | - Douglas B McCreery
- Neural Engineeiring Laboratory, Huntington Medical Research Institute, 734 Fairmount Avenue, Pasadena CA 91105, USA, Pasadena, California, 91105, UNITED STATES
| | - Martin Han
- Biomedical Engineering, University of Connecticut at Storrs , 260 Glenbrook Rd., Unit 3247, Storrs, Connecticut, 06269-3247, UNITED STATES
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Bertrand MM, Korajkic N, Osborne PB, Keast JR. Functional segregation within the pelvic nerve of male rats: a meso- and microscopic analysis. J Anat 2020; 237:757-773. [PMID: 32598494 PMCID: PMC7495281 DOI: 10.1111/joa.13221] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/22/2020] [Accepted: 04/27/2020] [Indexed: 01/16/2023] Open
Abstract
The pelvic splanchnic nerves are essential for pelvic organ function and have been proposed as targets for neuromodulation. We have focused on the rodent homologue of these nerves, the pelvic nerves. Our goal was to define within the pelvic nerve the projections of organ-specific sensory axons labelled by microinjection of neural tracer (cholera toxin, subunit B) into the bladder, urethra or rectum. We also examined the location of peptidergic sensory axons within the pelvic nerves to determine whether they aggregated separately from sacral preganglionic and paravertebral sympathetic postganglionic axons travelling in the same nerve. To address these aims, microscopy was performed on the major pelvic ganglion (MPG) with attached pelvic nerves, microdissected from young adult male Sprague-Dawley rats (6-8 weeks old) and processed as whole mounts for fluorescence immunohistochemistry. The pelvic nerves were typically composed of five discrete fascicles. Each fascicle contained peptidergic sensory, cholinergic preganglionic and noradrenergic postganglionic axons. Sensory axons innervating the lower urinary tract (LUT) consistently projected in specific fascicles within the pelvic nerves, whereas sensory axons innervating the rectum projected in a complementary group of fascicles. These discrete aggregations of organ-specific sensory projections could be followed along the full length of the pelvic nerves. From the junction of the pelvic nerve with the MPG, sensory axons immunoreactive for calcitonin gene-related peptide (CGRP) showed several distinct patterns of projection: some projected directly to the cavernous nerve, others projected directly across the surface of the MPG to the accessory nerves and a third class entered the MPG, encircling specific cholinergic neurons projecting to the LUT. A subpopulation of preganglionic inputs to noradrenergic MPG neurons also showed CGRP immunoreactivity. Together, these studies reveal new molecular and structural features of the pelvic nerves and suggest functional targets of sensory nerves in the MPG. These anatomical data will facilitate the design of experimental bioengineering strategies to specifically modulate each axon class.
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Affiliation(s)
- Martin M Bertrand
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Vic., Australia.,Department of Visceral Surgery, CHU de Nîmes, Nîmes, France.,Montpellier Laboratory of Informatics, Robotics and Microelectronics (LIRMM), ICAR Team, French National Centre for Scientific Research (CNRS), Montpellier University, Montpellier, France
| | - Nadja Korajkic
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Vic., Australia
| | - Peregrine B Osborne
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Vic., Australia
| | - Janet R Keast
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Vic., Australia
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Overstreet CK, Cheng J, Keefer EW. Fascicle specific targeting for selective peripheral nerve stimulation. J Neural Eng 2019; 16:066040. [PMID: 31509815 DOI: 10.1088/1741-2552/ab4370] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Electrical stimulation is a blunt tool for evoking neural activity. Neurons are naturally activated asynchronously and non-uniformly, whereas stimulation drives simultaneous activity within a population of cells. These differences in activation pattern can result in unintended side effects, including muddled sensory percepts and undesirable muscle contractions. These effects can be mitigated by the placement of electrodes in close approximation to nerve fibers and careful selection of the neural interface's location. This work describes the benefits of placing electrodes within specific fascicles of peripheral nerve to form selective neural interfaces for bidirectional neuroprosthetic devices. APPROACH Chronic electrodes were targeted to individual fascicles of the ulnar and median nerves in the forearm of four human subjects. During the surgical implant procedure, fascicles were dissected from each nerve, and functional testing was used to identify the relative composition of sensory and motor fibers within each. FAST-LIFE arrays, composed of longitudinal intrafascicular arrays and fascicular cuff electrodes, were implanted in each fascicle. The location, quality, and stimulation parameters associated with sensations evoked by electrical stimulation on these electrodes were characterized throughout the 90-180 d implant period. MAIN RESULTS FAST-LIFE arrays enable selective and chronic electrical stimulation of individual peripheral nerve fascicles. The quality of sensations evoked by stimulation in each fascicle is predictable and distinct; subjects reported tactile and cutaneous sensations during stimulation of sensory fascicles and deeper proprioceptive sensations during stimulation of motor fascicles. Stimulation thresholds and strength-duration time constants were typically higher within sensory fascicles. SIGNIFICANCE Highly selective, stable neural interfaces can be created by placing electrodes within and around single fascicles of peripheral nerves. This method enables targeting electrodes to nerve fibers that innervate a specific body region or have specific functions. Fascicle-specific interfacing techniques have broad potential to maximize the therapeutic effects of electrical stimulation in many neuromodulation applications. (Clinical Trial ID NCT02994160.).
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Steuer I, Guertin PA. Central pattern generators in the brainstem and spinal cord: an overview of basic principles, similarities and differences. Rev Neurosci 2019; 30:107-164. [PMID: 30543520 DOI: 10.1515/revneuro-2017-0102] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 03/30/2018] [Indexed: 12/11/2022]
Abstract
Central pattern generators (CPGs) are generally defined as networks of neurons capable of enabling the production of central commands, specifically controlling stereotyped, rhythmic motor behaviors. Several CPGs localized in brainstem and spinal cord areas have been shown to underlie the expression of complex behaviors such as deglutition, mastication, respiration, defecation, micturition, ejaculation, and locomotion. Their pivotal roles have clearly been demonstrated although their organization and cellular properties remain incompletely characterized. In recent years, insightful findings about CPGs have been made mainly because (1) several complementary animal models were developed; (2) these models enabled a wide variety of techniques to be used and, hence, a plethora of characteristics to be discovered; and (3) organizations, functions, and cell properties across all models and species studied thus far were generally found to be well-preserved phylogenetically. This article aims at providing an overview for non-experts of the most important findings made on CPGs in in vivo animal models, in vitro preparations from invertebrate and vertebrate species as well as in primates. Data about CPG functions, adaptation, organization, and cellular properties will be summarized with a special attention paid to the network for locomotion given its advanced level of characterization compared with some of the other CPGs. Similarities and differences between these networks will also be highlighted.
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Affiliation(s)
- Inge Steuer
- Neuroscience Unit, Laval University Medical Center (CHUL - CHU de Québec), 2705 Laurier Blvd, Quebec City, Quebec G1V 4G2, Canada
| | - Pierre A Guertin
- Neuroscience Unit, Laval University Medical Center (CHUL - CHU de Québec), 2705 Laurier Blvd, Quebec City, Quebec G1V 4G2, Canada
- Faculty of Medicine, Department of Psychiatry and Neurosciences, Laval University, Quebec City, Quebec G1V 0A6, Canada
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van der Lely S, Liechti MD, Popp WL, Schmidhalter MR, Kessler TM, Mehnert U. Does electrical stimulation in the lower urinary tract increase urine production? A randomised comparative proof-of-concept study in healthy volunteers. PLoS One 2019; 14:e0217503. [PMID: 31125385 PMCID: PMC6534346 DOI: 10.1371/journal.pone.0217503] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/08/2019] [Indexed: 01/23/2023] Open
Abstract
Trial design During electrical stimulation in the lower urinary tract for the purpose of current perception threshold and sensory evoked potential recording, we observed that bladder volume increased rapidly. The aim of this prospective randomised comparative proof-of-concept study was to quantify urine production per time during stimulation of the lower urinary tract using different stimulation frequencies. Methods Ninety healthy subjects (18 to 36 years old) were included. Forty females and 50 males were randomly assigned to one of the following study groups: dome, trigone or proximal, membranous (males only) or distal urethra. Starting from 60mL prefilling, stimulation was performed at two separate visits with a 14 French custom-made catheter using randomly applied frequencies of 0.5Hz, 1.1Hz, 1.6Hz (each with 500 stimuli). After each stimulation cycle per frequency, urine production was assessed. Main outcome measures represented urine production during stimulation, daily life and their ratio. Results Lower urinary tract electrical stimulation increased urine production per time compared to bladder diary baseline values. Linear mixed model showed that frequency (p<0.001), stimulation order (p = 0.003), intensity (p = 0.042), and gender (p = 0.047) had a significant influence on urine production. Location, visit and age had no significant influence. Conclusions Urine production is increased during electrical stimulation with a bigger impact of higher frequencies. This might be relevant for methodological aspects in the assessment of lower urinary tract afferent function and for patients with impaired renal urine output. Inhibition of renal sympathetic nerve activity by vagal afferents may be the underlying mechanism.
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Affiliation(s)
- Stéphanie van der Lely
- Department of Neuro-Urology, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Martina D. Liechti
- Department of Neuro-Urology, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Werner L. Popp
- Rehabilitation Engineering Lab, ETH Zürich, Zürich, Switzerland
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Melanie R. Schmidhalter
- Department of Neuro-Urology, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Thomas M. Kessler
- Department of Neuro-Urology, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Ulrich Mehnert
- Department of Neuro-Urology, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
- * E-mail:
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Barroso FO, Yoder B, Tentler D, Wallner JJ, Kinkhabwala AA, Jantz MK, Flint RD, Tostado PM, Pei E, Satish ADR, Brodnick SK, Suminski AJ, Williams JC, Miller LE, Tresch MC. Decoding neural activity to predict rat locomotion using intracortical and epidural arrays. J Neural Eng 2019; 16:036005. [DOI: 10.1088/1741-2552/ab0698] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Bullard AJ, Nason SR, Irwin ZT, Nu CS, Smith B, Campean A, Peckham PH, Kilgore KL, Willsey MS, Patil PG, Chestek CA. Design and testing of a 96-channel neural interface module for the Networked Neuroprosthesis system. Bioelectron Med 2019; 5:3. [PMID: 32232094 PMCID: PMC7098219 DOI: 10.1186/s42234-019-0019-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 01/25/2019] [Indexed: 11/20/2022] Open
Abstract
Background The loss of motor functions resulting from spinal cord injury can have devastating implications on the quality of one’s life. Functional electrical stimulation has been used to help restore mobility, however, current functional electrical stimulation (FES) systems require residual movements to control stimulation patterns, which may be unintuitive and not useful for individuals with higher level cervical injuries. Brain machine interfaces (BMI) offer a promising approach for controlling such systems; however, they currently still require transcutaneous leads connecting indwelling electrodes to external recording devices. While several wireless BMI systems have been designed, high signal bandwidth requirements limit clinical translation. Case Western Reserve University has developed an implantable, modular FES system, the Networked Neuroprosthesis (NNP), to perform combinations of myoelectric recording and neural stimulation for controlling motor functions. However, currently the existing module capabilities are not sufficient for intracortical recordings. Methods Here we designed and tested a 1 × 4 cm, 96-channel neural recording module prototype to fit within the specifications to mate with the NNP. The neural recording module extracts power between 0.3–1 kHz, instead of transmitting the raw, high bandwidth neural data to decrease power requirements. Results The module consumed 33.6 mW while sampling 96 channels at approximately 2 kSps. We also investigated the relationship between average spiking band power and neural spike rate, which produced a maximum correlation of R = 0.8656 (Monkey N) and R = 0.8023 (Monkey W). Conclusion Our experimental results show that we can record and transmit 96 channels at 2ksps within the power restrictions of the NNP system and successfully communicate over the NNP network. We believe this device can be used as an extension to the NNP to produce a clinically viable, fully implantable, intracortically-controlled FES system and advance the field of bioelectronic medicine.
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Affiliation(s)
- Autumn J Bullard
- 1Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI USA
| | - Samuel R Nason
- 1Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI USA
| | - Zachary T Irwin
- 1Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI USA
| | - Chrono S Nu
- 1Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI USA
| | - Brian Smith
- 2Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH USA
| | - Alex Campean
- 2Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH USA
| | - P Hunter Peckham
- 2Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH USA.,3Department of Orthopaedics, MetroHealth Medical Center, Cleveland, OH USA
| | - Kevin L Kilgore
- 2Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH USA.,3Department of Orthopaedics, MetroHealth Medical Center, Cleveland, OH USA.,4Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH USA
| | - Matthew S Willsey
- 5Department of Neurosurgery, University of Michigan, Ann Arbor, MI USA
| | - Parag G Patil
- 1Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI USA.,5Department of Neurosurgery, University of Michigan, Ann Arbor, MI USA.,6Department of Neurology, University of Michigan, Ann Arbor, MI USA.,7Department of Anesthesiology, University of Michigan, Ann Arbor, MI USA
| | - Cynthia A Chestek
- 1Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI USA.,8Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI USA
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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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Jung YS, Adem KMA, Bawazir SS, Stefanini C, Lee HJ. Implantable bladder volume sensor based on resistor ladder network composed of conductive hydrogel composite. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2017:1732-1735. [PMID: 29060221 DOI: 10.1109/embc.2017.8037177] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
An accurate bladder volume monitoring system is a critical component in diagnosis and treatment of urological disorders. Here, we report an implantable bladder volume sensor with a multi-level resistor ladder which estimates the bladder volume through discrete resistance values. Discretization allows the sensor output to be resilient to the long-term drift, hysteresis, and degradation of the sensor materials. Our sensor is composed of biocompatible polypyrrole/agarose hydrogel composite. Because Young's modulus of this composite is comparable to that of the bladder wall, the effect of mechanical loading of the sensor on the bladder movement is minimized which allows more accurate volume monitoring. We also demonstrate the patterning and molding capability of this material by fabrication various structures. Lastly, we successfully demonstrate the functionality of the multi-level resistor ladder sensor as a bladder volume sensor by attaching the sensor on the pig's bladder and observing the impedance change of the sensor.
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Gad PN, Kreydin E, Zhong H, Latack K, Edgerton VR. Non-invasive Neuromodulation of Spinal Cord Restores Lower Urinary Tract Function After Paralysis. Front Neurosci 2018; 12:432. [PMID: 30008661 PMCID: PMC6034097 DOI: 10.3389/fnins.2018.00432] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 06/08/2018] [Indexed: 12/17/2022] Open
Abstract
It is commonly assumed that restoration of locomotion is the ultimate goal after spinal cord injury (SCI). However, lower urinary tract (LUT) dysfunction is universal among SCI patients and significantly impacts their health and quality of life. Micturition is a neurologically complex behavior that depends on intact sensory and motor innervation. SCI disrupts both motor and sensory function and leads to marked abnormalities in urine storage and emptying. Current therapies for LUT dysfunction after SCI focus on preventing complications and managing symptoms rather than restoring function. In this study, we demonstrate that Transcutaneous Electrical Spinal Stimulation for LUT functional Augmentation (TESSLA), a non-invasive neuromodulatory technique, can reengage the spinal circuits' active in LUT function and normalize bladder and urethral sphincter function in individuals with SCI. Specifically, TESSLA reduced detrusor overactivity (DO), decreased detrusor-sphincter dyssynergia (DSD), increased bladder capacity and enabled voiding. TESSLA may represent a novel approach to transform the intrinsic spinal networks to a more functionally physiological state. Each of these features has significant clinical implications. Improvement and restoration of LUT function after SCI stand to significantly benefit patients by improving their quality of life and reducing the risk of incontinence, kidney injury and urinary tract infection, all the while lowering healthcare costs.
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Affiliation(s)
- Parag N Gad
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States.,Rancho Los Amigos National Rehabilitation Center, Downey, CA, United States
| | - Evgeniy Kreydin
- Rancho Los Amigos National Rehabilitation Center, Downey, CA, United States.,Institute of Urology, Keck School of Medicine of University of Southern California, Los Angeles, CA, United States
| | - Hui Zhong
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States.,Rancho Los Amigos National Rehabilitation Center, Downey, CA, United States
| | - Kyle Latack
- Rancho Los Amigos National Rehabilitation Center, Downey, CA, United States.,Institute of Urology, Keck School of Medicine of University of Southern California, Los Angeles, CA, United States
| | - V Reggie Edgerton
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Neurobiology, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, United States.,Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, United States.,Institut Guttmann, Hospital de Neurorehabilitació, Institut Universitari Adscrit a la Universitat Autònoma de Barcelona, Barcelona, Spain.,Faculty of Science, The Centre for Neuroscience and Regenerative Medicine, University of Technology Sydney, Ultimo, NSW, Australia
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15
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Wong YT, Ahnood A, Maturana MI, Kentler W, Ganesan K, Grayden DB, Meffin H, Prawer S, Ibbotson MR, Burkitt AN. Feasibility of Nitrogen Doped Ultrananocrystalline Diamond Microelectrodes for Electrophysiological Recording From Neural Tissue. Front Bioeng Biotechnol 2018; 6:85. [PMID: 29988378 PMCID: PMC6024013 DOI: 10.3389/fbioe.2018.00085] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 06/05/2018] [Indexed: 01/19/2023] Open
Abstract
Neural prostheses that can monitor the physiological state of a subject are becoming clinically viable through improvements in the capacity to record from neural tissue. However, a significant limitation of current devices is that it is difficult to fabricate electrode arrays that have both high channel counts and the appropriate electrical properties required for neural recordings. In earlier work, we demonstrated nitrogen doped ultrananocrystalline diamond (N-UNCD) can provide efficacious electrical stimulation of neural tissue, with high charge injection capacity, surface stability and biocompatibility. In this work, we expand on this functionality to show that N-UNCD electrodes can also record from neural tissue owing to its low electrochemical impedance. We show that N-UNCD electrodes are highly flexible in their application, with successful recordings of action potentials from single neurons in an in vitro retina preparation, as well as local field potential responses from in vivo visual cortex tissue. Key properties of N-UNCD films, combined with scalability of electrode array fabrication with custom sizes for recording or stimulation along with integration through vertical interconnects to silicon based integrated circuits, may in future form the basis for the fabrication of versatile closed-loop neural prostheses that can both record and stimulate.
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Affiliation(s)
- Yan T. Wong
- Department of Physiology and Department of Electrical and Computer Systems Engineering, Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Arman Ahnood
- School of Physics, University of Melbourne, Melbourne, VIC, Australia
| | - Matias I. Maturana
- Department of Biomedical Engineering, University of Melbourne, Melbourne, VIC, Australia
- National Vision Research Institute, Australian College of Optometry, Carlton, VIC, Australia
| | - William Kentler
- Department of Biomedical Engineering, University of Melbourne, Melbourne, VIC, Australia
| | | | - David B. Grayden
- Department of Biomedical Engineering, University of Melbourne, Melbourne, VIC, Australia
| | - Hamish Meffin
- National Vision Research Institute, Australian College of Optometry, Carlton, VIC, Australia
- Department of Optometry and Vision Science University of Melbourne, Melbourne, VIC, Australia
| | - Steven Prawer
- School of Physics, University of Melbourne, Melbourne, VIC, Australia
| | - Michael R. Ibbotson
- National Vision Research Institute, Australian College of Optometry, Carlton, VIC, Australia
- Department of Optometry and Vision Science University of Melbourne, Melbourne, VIC, Australia
| | - Anthony N. Burkitt
- Department of Biomedical Engineering, University of Melbourne, Melbourne, VIC, Australia
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16
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Brill N, Naufel SN, Polasek K, Ethier C, Cheesborough J, Agnew S, Miller LE, Tyler DJ. Evaluation of high-density, multi-contact nerve cuffs for activation of grasp muscles in monkeys. J Neural Eng 2018; 15:036003. [PMID: 28825407 PMCID: PMC5910281 DOI: 10.1088/1741-2552/aa8735] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The objective of this work was to evaluate whether nerve cuffs can selectively activate hand muscles for functional electrical stimulation (FES). FES typically involves identifying and implanting electrodes in many individual muscles, but nerve cuffs only require implantation at a single site around the nerve. This method is surgically more attractive. Nerve cuffs may also more effectively stimulate intrinsic hand muscles, which are difficult to implant and stimulate without spillover to adjacent muscles. APPROACH To evaluate its ability to selectively activate muscles, we implanted and tested the flat interface nerve electrode (FINE), which is designed to selectively stimulate peripheral nerves that innervate multiple muscles (Tyler and Durand 2002 IEEE Trans. Neural Syst. Rehabil. Eng. 10 294-303). We implanted FINEs on the nerves and bipolar intramuscular wires for recording compound muscle action potentials (CMAPs) from up to 20 muscles in each arm of six monkeys. We then collected recruitment curves while the animals were anesthetized. MAIN RESULT A single FINE implanted on an upper extremity nerve in the monkey can selectively activate muscles or small groups of muscles to produce multiple, independent hand functions. SIGNIFICANCE FINE cuffs can serve as a viable supplement to intramuscular electrodes in FES systems, where they can better activate intrinsic and extrinsic muscles with lower currents and less extensive surgery.
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Affiliation(s)
| | - SN Naufel
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
| | - K Polasek
- Department of Engineering, Hope College, 27 Graves Pl. Holland MI, 49423
| | - C Ethier
- Centre de recherche de l’Institut universitaire en santé mentale de Québec, Department of Psychiatry and Neuroscience, Université Laval, Quebec City, QC, Canada
| | - J Cheesborough
- Clinical Instructor, Surgery, Plastic & Reconstructive Surgery, Stanford University
| | - S Agnew
- Assistant Professor, Division of Plastic Surgery and Department of Orthopaedic Surgery, Loyola University Medical Center
| | - LE Miller
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Avenue, Chicago, IL 60611, USA
- Sensory Motor Performance Program (SMPP), Shirley Ryan Ability Lab, 355 Erie Street, Suite 1406, Chicago, IL 60611, USA
- Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL, USA
| | - DJ Tyler
- Biomedical Engineering Department, Case Western Reserve University, Cleveland, OH, USA
- Louis Stokes Veterans Affairs Medical Center, Cleveland, OH, USA
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17
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Wheeler TL, de Groat W, Eisner K, Emmanuel A, French J, Grill W, Kennelly MJ, Krassioukov A, Gallo Santacruz B, Biering-Sørensen F, Kleitman N. Translating promising strategies for bowel and bladder management in spinal cord injury. Exp Neurol 2018; 306:169-176. [PMID: 29753647 PMCID: PMC8117184 DOI: 10.1016/j.expneurol.2018.05.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/23/2018] [Accepted: 05/01/2018] [Indexed: 12/18/2022]
Abstract
Loss of control over voiding following spinal cord injury (SCI) impacts autonomy, participation and dignity, and can cause life-threatening complications. The importance of SCI bowel and bladder dysfunction warrants significantly more attention from researchers in the field. To address this gap, key SCI clinicians, researchers, government and private funding organizations met to share knowledge and examine emerging approaches. This report reviews recommendations from this effort to identify and prioritize near-term treatment, investigational and translational approaches to addressing the pressing needs of people with SCI.
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Affiliation(s)
- Tracey L Wheeler
- Craig H. Neilsen Foundation, 16830 Ventura Blvd, Suite 352, Encino, CA 91436, United States.
| | - William de Groat
- University of Pittsburgh, Department of Pharmacology and Chemical Biology, W-1352 Starzl Biomedical Science Tower, University of Pittsburgh Medical School, 200 Lothrop Street, Pittsburgh, PA 15261, United States.
| | - Kymberly Eisner
- Craig H. Neilsen Foundation, 16830 Ventura Blvd, Suite 352, Encino, CA 91436, United States
| | - Anton Emmanuel
- GI Physiology Unit, University College Hospital, London NW1 2BU, UK.
| | - Jennifer French
- Neurotech Network, PO Box 16776, Saint Petersburg, FL 33733, United States.
| | - Warren Grill
- Duke University, Department of Biomedical Engineering, Fitzpatrick CIEMAS, Room 1427, Box 90281, Durham, NC 27708-0281, United States.
| | - Michael J Kennelly
- Carolinas HealthCare System, McKay Urology, 1023 Edgehill Road South, Charlotte, NC 28207, United States.
| | - Andrei Krassioukov
- ICORD, University of British Columbia, GF Strong Rehabilitation Centre, 818 West 10th Avenue, Vancouver, British Columbia V5Z 1M9, Canada
| | | | - Fin Biering-Sørensen
- Rigshospitalet (2081), Blegdamsvej 9, DK-2100 Copenhagen, Denmark; University of Copenhagen, Clinic for Spinal Cord Injuries, NeuroScience Centre Havnevej 25, DK-3100 Hornbæk, Denmark
| | - Naomi Kleitman
- Craig H. Neilsen Foundation, 16830 Ventura Blvd, Suite 352, Encino, CA 91436, United States
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18
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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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19
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Gad PN, Kokikian N, Christe KL, Edgerton VR, Havton LA. Noninvasive neurophysiological mapping of the lower urinary tract in adult and aging rhesus macaques. J Neurophysiol 2018; 119:1521-1527. [PMID: 29361664 DOI: 10.1152/jn.00840.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The lower urinary tract (LUT) may be activated by spinal cord stimulation, but the physiological mapping characteristics of LUT activation with noninvasive transcutaneous spinal cord stimulation (TSCS) are not known. The effects of aging on the contractile properties of the detrusor are also not well understood. Therefore, TSCS was applied over the T10/T11 to L6/L7 spinous processes in adult ( n = 6) and aged ( n = 9) female rhesus macaques. A combination of urodynamic studies and electromyography recordings of the external urethral sphincter (EUS), external anal sphincter (EAS), and pelvic floor muscles was performed. Distinct functional maps were demonstrated for TSCS-evoked detrusor and urethral pressures and for the activation of the EUS, EAS, and pelvic floor muscles. The magnitude of responses for each peripheral target organ was dependent on TSCS location and strength. The strongest detrusor contraction was observed with TSCS at the L1/L2 site in adults and the L3/L4 site in aged subjects. TSCS-evoked bladder pressure at the L1/L2 site was significantly higher for the adults compared with the aged subjects ( P < 0.05). Cumulative normalized TSCS-evoked pressures, calculated for five consecutive sites between the T11/T12 and L3/L4 levels, were significantly lower for aged compared with adult subjects ( P < 0.05). The aged animals also showed a caudal shift for the TSCS site that generated the strongest detrusor contraction. We conclude that natural aging in rhesus macaques is associated with decreased detrusor contractility, a finding of significant translational research relevance as detrusor underactivity is a common occurrence with aging in humans. NEW & NOTEWORTHY Transcutaneous spinal cord stimulation (TSCS) was used to map lower urinary tract function in adult and aged rhesus macaques. Aging was associated with decreased peak pressure responses to TSCS, reduced cumulative normalized evoked bladder pressure responses, and a caudal shift for the site generating the strongest TSCS-induced detrusor contraction. We demonstrate the utility of TSCS as a new diagnostic tool for detrusor contractility assessments and conclude that aging is associated with decreased detrusor contractility in primates.
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Affiliation(s)
- Parag N Gad
- Department of Integrative Biology and Physiology, University of California , Los Angeles, California
| | - Nelly Kokikian
- Department of Integrative Biology and Physiology, University of California , Los Angeles, California
| | - Kari L Christe
- California National Primate Research Center, University of California , Davis, California
| | - V Reggie Edgerton
- Department of Integrative Biology and Physiology, University of California , Los Angeles, California.,Department of Neurobiology, David Geffen School of Medicine at University of California , Los Angeles, California.,Department of Neurosurgery, David Geffen School of Medicine at University of California , Los Angeles, California.,Brain Research Institute, University of California , Los Angeles, California.,Institut Guttmann, Hospital de Neurorehabilitació, Universitat Autònoma de Barcelona, Badalona, Spain.,Centre for Neuroscience and Regenerative Medicine, University of Technology , Sydney , Australia
| | - Leif A Havton
- Department of Neurobiology, David Geffen School of Medicine at University of California , Los Angeles, California.,Department of Neurology, David Geffen School of Medicine at University of California , Los Angeles, California
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20
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Hassani FA, Peh WYX, Gammad GGL, Mogan RP, Ng TK, Kuo TLC, Ng LG, Luu P, Yen S, Lee C. A 3D Printed Implantable Device for Voiding the Bladder Using Shape Memory Alloy (SMA) Actuators. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2017; 4:1700143. [PMID: 29201606 PMCID: PMC5700638 DOI: 10.1002/advs.201700143] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/09/2017] [Indexed: 05/08/2023]
Abstract
Underactive bladder or detrusor underactivity (DU) is defined as a reduction of contraction strength or duration of the bladder wall. Despite the serious healthcare implications of DU, there are limited solutions for affected individuals. A flexible 3D printed implantable device driven by shape memory alloys (SMA) actuators is presented here for the first time to physically contract the bladder to restore voluntary control of the bladder for individuals suffering from DU. This approach is used initially in benchtop experiments with a rubber balloon acting as a model for the rat bladder to verify its potential for voiding, and that the operating temperatures are safe for the eventual implantation of the device in a rat. The device is then implanted and tested on an anesthetized rat, and a voiding volume of more than 8% is successfully achieved for the SMA-based device without any surgical intervention or drug injection to relax the external sphincter.
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Affiliation(s)
- Faezeh Arab Hassani
- Department of Electrical and Computer EngineeringFaculty of EngineeringNational University of Singapore4 Engineering Drive 3, #05‐45Singapore117583Singapore
- Singapore Institute for NeurotechnologyNational University of Singapore28 Medical Dr. #05‐CORSingapore117456Singapore
- Center for Intelligent Sensors and MEMSNational University of Singapore4 Engineering Drive 3Singapore117576Singapore
- Biomedical Institute for Global Health Research and Technology (BIGHEART)Yong Loo Lin School of MedicineNational University of Singapore14 Medical Drive #14‐01Singapore117599Singapore
| | - Wendy Yen Xian Peh
- Singapore Institute for NeurotechnologyNational University of Singapore28 Medical Dr. #05‐CORSingapore117456Singapore
| | - Gil Gerald Lasam Gammad
- Singapore Institute for NeurotechnologyNational University of Singapore28 Medical Dr. #05‐CORSingapore117456Singapore
| | - Roshini Priya Mogan
- Singapore Institute for NeurotechnologyNational University of Singapore28 Medical Dr. #05‐CORSingapore117456Singapore
| | - Tze Kiat Ng
- Raffles Hospital585 North Bridge RoadSingapore188770Singapore
| | | | - Lay Guat Ng
- Singapore General HospitalOutram RoadSingapore169608Singapore
| | - Percy Luu
- Singapore Institute for NeurotechnologyNational University of Singapore28 Medical Dr. #05‐CORSingapore117456Singapore
| | - Shih‐Cheng Yen
- Department of Electrical and Computer EngineeringFaculty of EngineeringNational University of Singapore4 Engineering Drive 3, #05‐45Singapore117583Singapore
- Singapore Institute for NeurotechnologyNational University of Singapore28 Medical Dr. #05‐CORSingapore117456Singapore
- Center for Intelligent Sensors and MEMSNational University of Singapore4 Engineering Drive 3Singapore117576Singapore
| | - Chengkuo Lee
- Department of Electrical and Computer EngineeringFaculty of EngineeringNational University of Singapore4 Engineering Drive 3, #05‐45Singapore117583Singapore
- Singapore Institute for NeurotechnologyNational University of Singapore28 Medical Dr. #05‐CORSingapore117456Singapore
- Center for Intelligent Sensors and MEMSNational University of Singapore4 Engineering Drive 3Singapore117576Singapore
- Biomedical Institute for Global Health Research and Technology (BIGHEART)Yong Loo Lin School of MedicineNational University of Singapore14 Medical Drive #14‐01Singapore117599Singapore
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21
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Prototype Deep Brain Stimulation System with Closed-Loop Control Feedback for Modulating Bladder Functions in Traumatic Brain Injured Animals. J Med Biol Eng 2017. [DOI: 10.1007/s40846-017-0326-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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22
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McGee MJ, Swan BD, Danziger ZC, Amundsen CL, Grill WM. Multiple Reflex Pathways Contribute to Bladder Activation by Intraurethral Stimulation in Persons With Spinal Cord Injury. Urology 2017; 109:210-215. [PMID: 28801220 DOI: 10.1016/j.urology.2017.07.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/22/2017] [Accepted: 07/28/2017] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To measure the urodynamic effects of electrical co-stimulation of 2 individual sites in the proximal and distal urethra in persons with spinal cord injury (SCI). This work was motivated by preclinical findings that selective co-stimulation of the cranial urethral sensory nerve and the dorsal genital nerve, which innervate the proximal and distal portions of the urethra, respectively, increased reflex bladder activation and voiding efficiency. MATERIALS AND METHODS Electrical co-stimulation of urethral afferents was conducted in persons with chronic SCI during urodynamics. The effects of different frequencies of intraurethral stimulation at multiple urethral locations on bladder pressure and pelvic floor electromyographic activity were measured. RESULTS Electromyographic activity indicated that multiple reflex pathways were recruited through stimulation that contributed to bladder activation. The size of reflex bladder contractions evoked by stimulation was dependent on stimulation location or reflex activated and stimulation frequency. CONCLUSION Pudendal nerve afferents are a promising target to restore lost bladder control, as stimulation with different frequencies may be used to treat urinary incontinence and increase continent volumes or to generate stimulation-evoked bladder contractions for on-demand voiding. This work identified that co-stimulation of multiple afferent reflex pathways can enhance activation of spinal circuits and may enable improved bladder emptying in SCI when stimulation of a single pathway is not sufficient.
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Affiliation(s)
- Meredith J McGee
- Department of Biomedical Engineering, Duke University, Durham, NC
| | - Brandon D Swan
- Department of Biomedical Engineering, Duke University, Durham, NC
| | | | - Cindy L Amundsen
- Department of Obstetrics and Gynecology, Division of Urogynecology and Reconstructive Pelvic Surgery, Duke University Medical Center, Durham, NC
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, NC; Department of Neurobiology, Duke University, Durham, NC; Department of Neurosurgery, Duke University, Durham, NC; Department of Electrical and Computer Engineering, Duke University, Durham, NC.
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23
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Ahmed Z. Effects of cathodal trans-spinal direct current stimulation on lower urinary tract function in normal and spinal cord injury mice with overactive bladder. J Neural Eng 2017; 14:056002. [DOI: 10.1088/1741-2552/aa76f2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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24
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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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25
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Cohn JA, Kaufman MR, Dmochowski RR, Kowalik CG, Milam DF, Reynolds WS. Early Sacral Neuromodulation in Spinal Cord Injury—Can It Regenerate Nerves? CURRENT BLADDER DYSFUNCTION REPORTS 2016. [DOI: 10.1007/s11884-016-0382-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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26
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Ross SE, Sperry ZJ, Mahar CM, Bruns TM. Hysteretic behavior of bladder afferent neurons in response to changes in bladder pressure. BMC Neurosci 2016; 17:57. [PMID: 27520434 PMCID: PMC4983075 DOI: 10.1186/s12868-016-0292-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 08/01/2016] [Indexed: 01/16/2023] Open
Abstract
Background Mechanosensitive afferents innervating the bladder increase their firing rate as the bladder fills and pressure rises. However, the relationship between afferent firing rates and intravesical pressure is not a simple linear one. Firing rate responses to pressure can differ depending on prior activity, demonstrating hysteresis in the system. Though this hysteresis has been commented on in published literature, it has not been quantified. Results Sixty-six bladder afferents recorded from sacral dorsal root ganglia in five alpha-chloralose anesthetized felines were identified based on their characteristic responses to pressure (correlation coefficient ≥ 0.2) during saline infusion (2 ml/min). For saline infusion trials, we calculated a maximum hysteresis ratio between the firing rate difference at each pressure and the overall firing rate range (or Hmax) of 0.86 ± 0.09 (mean ± standard deviation) and mean hysteresis ratio (or Hmean) of 0.52 ± 0.13 (n = 46 afferents). For isovolumetric trials in two experiments (n = 33 afferents) Hmax was 0.72 ± 0.14 and Hmean was 0.40 ± 0.14. Conclusions A comprehensive state model that integrates these hysteresis parameters to determine the bladder state may improve upon existing neuroprostheses for bladder control.
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Affiliation(s)
- Shani E Ross
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA.,, NCRC-B20-104W, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
| | - Zachariah J Sperry
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA.,, NCRC-B20-111WD, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
| | - Colin M Mahar
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, USA.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA.,, NCRC-B20-111WD, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
| | - Tim M Bruns
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA. .,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA. .,, NCRC-B10-A169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA.
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Ethier C, Miller LE. Brain-controlled muscle stimulation for the restoration of motor function. Neurobiol Dis 2015; 83:180-90. [PMID: 25447224 PMCID: PMC4412757 DOI: 10.1016/j.nbd.2014.10.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Revised: 10/14/2014] [Accepted: 10/20/2014] [Indexed: 12/21/2022] Open
Abstract
Loss of the ability to move, as a consequence of spinal cord injury or neuromuscular disorder, has devastating consequences for the paralyzed individual, and great economic consequences for society. Functional electrical stimulation (FES) offers one means to restore some mobility to these individuals, improving not only their autonomy, but potentially their general health and well-being as well. FES uses electrical stimulation to cause the paralyzed muscles to contract. Existing clinical systems require the stimulation to be preprogrammed, with the patient typically using residual voluntary movement of another body part to trigger and control the patterned stimulation. The rapid development of neural interfacing in the past decade offers the promise of dramatically improved control for these patients, potentially allowing continuous control of FES through signals recorded from motor cortex, as the patient attempts to control the paralyzed body part. While application of these 'brain-machine interfaces' (BMIs) has undergone dramatic development for control of computer cursors and even robotic limbs, their use as an interface for FES has been much more limited. In this review, we consider both FES and BMI technologies and discuss the prospect for combining the two to provide important new options for paralyzed individuals.
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Affiliation(s)
- Christian Ethier
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL 60611, USA
| | - Lee E Miller
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL 60611, USA; Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road Evanston, IL 60208, USA; Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, 345 E. Superior Ave., Chicago, IL 60611, USA.
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Shiraz AN, Craggs M, Leaker B, Demosthenous A. Minimizing Stimulus Current in a Wearable Pudendal Nerve Stimulator Using Computational Models. IEEE Trans Neural Syst Rehabil Eng 2015; 24:506-15. [PMID: 26415182 DOI: 10.1109/tnsre.2015.2480755] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
After spinal cord injury, functions of the lower urinary tract may be disrupted. A wearable device with surface electrodes which can effectively control the bladder functions would be highly beneficial to the patients. A trans-rectal pudendal nerve stimulator may provide such a solution. However, the major limiting factor in such a stimulator is the high level of current it requires to recruit the nerve fibers. Also, the variability of the trajectory of the nerve in different individuals should be considered. Using computational models and an approximate trajectory of the nerve derived from an MRI study, it is demonstrated in this paper that it may be possible to considerably reduce the required current levels for trans-rectal stimulation of the pudendal nerve compared to the values previously reported in the literature. This was corroborated by considering an ensemble of possible and probable variations of the trajectory. The outcome of this study suggests that trans-rectal stimulation of the pudendal nerve is a plausible long term solution for treating lower urinary tract dysfunctions after spinal cord injury.
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Lee S, Yen SC, Sheshadri S, Delgado-Martinez I, Xue N, Xiang Z, Thakor NV, Lee C. Flexible Epineural Strip Electrode for Recording in Fine Nerves. IEEE Trans Biomed Eng 2015; 63:581-7. [PMID: 26276980 DOI: 10.1109/tbme.2015.2466442] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This paper demonstrates flexible epineural strip electrodes (FLESE) for recording from small nerves. Small strip-shaped FLESE enables us to easily and closely stick on various sized nerves for less damage in a nerve and optimal recording quality. In addition, in order to enhance the neural interface, the gold electrode contacts were coated with carbon nanotubes, which reduced the impedance of the electrodes. We used the FLESEs to record electrically elicited nerve signals (compound neural action potentials) from the sciatic nerve in rats. Bipolar and differential bipolar configurations for the recording were investigated to optimize the recording configuration of the FLESEs. The successful results from differential bipolar recordings showed that the total length of FLESEs could be further reduced, maintaining the maximum recording ability, which would be beneficial for recording in very fine nerves. Our results demonstrate that new concept of FLESEs could play an important role in electroceuticals in near future.
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Taghipour-Farshi H, Frounchi J, Ahmadiasl N, Shahabi P, Salekzamani Y. Effect of contacts configuration and location on selective stimulation of cuff electrode. Biomed Mater Eng 2015; 25:237-48. [DOI: 10.3233/bme-151281] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
| | - Javad Frounchi
- Department of Electrical and Computer Engineering, Tabriz University, Tabriz, Iran
| | - Nasser Ahmadiasl
- Department of Neurosciences, School of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Parviz Shahabi
- Department of Neurosciences, School of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Yaghoub Salekzamani
- Physical Medicine and Rehabilitation Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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Ho CH, Triolo RJ, Elias AL, Kilgore KL, DiMarco AF, Bogie K, Vette AH, Audu ML, Kobetic R, Chang SR, Chan KM, Dukelow S, Bourbeau DJ, Brose SW, Gustafson KJ, Kiss ZHT, Mushahwar VK. Functional electrical stimulation and spinal cord injury. Phys Med Rehabil Clin N Am 2015; 25:631-54, ix. [PMID: 25064792 DOI: 10.1016/j.pmr.2014.05.001] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Spinal cord injuries (SCI) can disrupt communications between the brain and the body, resulting in loss of control over otherwise intact neuromuscular systems. Functional electrical stimulation (FES) of the central and peripheral nervous system can use these intact neuromuscular systems to provide therapeutic exercise options to allow functional restoration and to manage medical complications following SCI. The use of FES for the restoration of muscular and organ functions may significantly decrease the morbidity and mortality following SCI. Many FES devices are commercially available and should be considered as part of the lifelong rehabilitation care plan for all eligible persons with SCI.
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Affiliation(s)
- Chester H Ho
- Division of Physical Medicine & Rehabilitation, Department of Clinical Neurosciences, Foothills Medical Centre, Room 1195, 1403-29th Street NW, Calgary, Alberta T2N 2T9, Canada.
| | - Ronald J Triolo
- Louis Stokes Cleveland VA Medical Center, Advanced Platform Technology Center, 151 AW/APT, 10701 East Boulevard, Cleveland, OH 44106, USA; Department of Orthopaedics, Case Western Reserve University, MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH 44109, USA; 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
| | - Anastasia L Elias
- Chemical and Materials Engineering, W7-002 ECERF, University of Alberta, Edmonton, Alberta T6G 2V4, Canada
| | - 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 Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA; Cleveland FES Center, 11000 Cedar Avenue, Suite 230, Cleveland, OH 44106-3056, USA
| | - Anthony F DiMarco
- MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH 44109, USA; Cleveland FES Center, 11000 Cedar Avenue, Suite 230, Cleveland, OH 44106-3056, USA
| | - Kath Bogie
- Louis Stokes Cleveland VA Medical Center, Advanced Platform Technology Center, 151 AW/APT, 10701 East Boulevard, Cleveland, OH 44106, USA; Department of Orthopaedics, Case Western Reserve University, MetroHealth Medical Center, 2500 MetroHealth Drive, Cleveland, OH 44109, USA; Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA
| | - Albert H Vette
- Department of Mechanical Engineering, University of Alberta, 4-9 Mechanical Engineering Building, Edmonton, Alberta T6G 2G8, Canada; Glenrose Rehabilitation Hospital, Alberta Health Services, 10230 - 111 Avenue, Edmonton, Alberta T5G 0B7, Canada
| | - Musa L Audu
- Louis Stokes Cleveland VA Medical Center, Advanced Platform Technology Center, 151 AW/APT, 10701 East Boulevard, Cleveland, OH 44106, USA; Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Rudi Kobetic
- Louis Stokes Cleveland VA Medical Center, Advanced Platform Technology Center, 151 AW/APT, 10701 East Boulevard, Cleveland, OH 44106, USA
| | - Sarah R Chang
- Louis Stokes Cleveland VA Medical Center, Advanced Platform Technology Center, 151 AW/APT, 10701 East Boulevard, Cleveland, OH 44106, USA; Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - K Ming Chan
- Division of Physical Medicine and Rehabilitation, Centre for Neuroscience, University of Alberta, 5005 Katz Group Centre, 11361-87 Avenue, Edmonton, Alberta T6G 2E1, Canada
| | - Sean Dukelow
- Division of Physical Medicine & Rehabilitation, Department of Clinical Neurosciences, Foothills Medical Centre, Room 1195, 1403-29th Street NW, Calgary, Alberta T2N 2T9, Canada
| | - Dennis J Bourbeau
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA; Cleveland FES Center, 11000 Cedar Avenue, Suite 230, Cleveland, OH 44106-3056, USA
| | - Steven W Brose
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA; Cleveland FES Center, 11000 Cedar Avenue, Suite 230, Cleveland, OH 44106-3056, USA; Ohio University Heritage College of Osteopathic Medicine, Grosvenor Hall, Athens, OH 45701, USA
| | - Kenneth J Gustafson
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA; Cleveland FES Center, 11000 Cedar Avenue, Suite 230, Cleveland, OH 44106-3056, USA
| | - Zelma H T Kiss
- Department of Clinical Neurosciences, Foothills Medical Centre, Room 1195, 1403-29th Street NW, Calgary, Alberta T2N 2T9, Canada
| | - Vivian K Mushahwar
- Division of Physical Medicine and Rehabilitation, Centre for Neuroscience, University of Alberta, 5005 Katz Group Centre, 11361-87 Avenue, Edmonton, Alberta T6G 2E1, Canada
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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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McCoin JL, Bhadra N, Brose SW, Gustafson KJ. Does patterned afferent stimulation of sacral dermatomes suppress urethral sphincter reflexes in individuals with spinal cord injury? Neurourol Urodyn 2014; 34:219-23. [DOI: 10.1002/nau.22545] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 11/15/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Jaime L. McCoin
- Neural Engineering Center; Department of Biomedical Engineering; Case Western Reserve University; Wickenden Building, Room 114, 10900 Euclid Avenue Cleveland Ohio 44106
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Cleveland Ohio
| | - Narendra Bhadra
- Neural Engineering Center; Department of Biomedical Engineering; Case Western Reserve University; Wickenden Building, Room 114, 10900 Euclid Avenue Cleveland Ohio 44106
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Cleveland Ohio
| | - Steven W. Brose
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Cleveland Ohio
- Case Western Reserve University, Department of PM+R; Cleveland Ohio
- Ohio University Heritage College of Osteopathic Medicine; Athens Ohio
| | - Kenneth J. Gustafson
- Neural Engineering Center; Department of Biomedical Engineering; Case Western Reserve University; Wickenden Building, Room 114, 10900 Euclid Avenue Cleveland Ohio 44106
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Cleveland Ohio
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Bruns TM, Weber DJ, Gaunt RA. Microstimulation of afferents in the sacral dorsal root ganglia can evoke reflex bladder activity. Neurourol Urodyn 2014; 34:65-71. [PMID: 24464833 DOI: 10.1002/nau.22514] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 09/19/2013] [Indexed: 11/07/2022]
Abstract
AIMS Pudendal afferent fibers can be excited using electrical stimulation to evoke reflex bladder activity. While this approach shows promise for restoring bladder function, stimulation of desired pathways, and integration of afferent signals for sensory feedback remains challenging. At sacral dorsal root ganglia (DRG), the convergence of pelvic and pudendal afferent fibers provides a unique location for access to lower urinary tract neurons. Our goal in this study was to demonstrate the potential of microstimulation in sacral DRG for evoking reflex bladder responses. METHODS Penetrating microelectrode arrays were inserted in the left S1 and S2 DRG of six anesthetized adult male cats. While the bladder volume was held at a level below the leak volume, single and multiple channel stimulation was performed using various stimulation patterns. RESULTS Reflex bladder excitation was observed in five cats, for stimulation in either S1 or S2 DRG at 1 Hz and 30-33 Hz with a pulse amplitude of 10-50 µA. Bladder relaxation was observed during a few trials. Adjacent electrodes frequently elicited very different responses. CONCLUSIONS These results demonstrate the potential of low-current microstimulation to recruit reflexive bladder responses. An approach such as this could be integrated with DRG recordings of bladder afferents to provide a closed-loop bladder neuroprosthesis.
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Affiliation(s)
- Tim M Bruns
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennysylvania
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Bîrlea SI, Breen PP, Corley GJ, Bîrlea NM, Quondamatteo F, ÓLaighin G. Changes in the electrical properties of the electrode-skin-underlying tissue composite during a week-long programme of neuromuscular electrical stimulation. Physiol Meas 2014; 35:231-52. [PMID: 24434816 DOI: 10.1088/0967-3334/35/2/231] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Particular neuromuscular electrical stimulation (NMES) applications require the use of the same electrodes over a long duration (>1 day) without having access to them. Under such circumstance the quality of the electrode-skin contact cannot be assessed. We used the NMES signal itself to assess the quality of the electrode-skin contact and the electrical properties of the underlying tissues over a week. A 14% decrease in the skin's stratum corneum resistance (from 20 to 17 kΩ) and a 15% decrease in the resistance of the electrodes and underlying tissues (from 550 to 460 Ω) were observed in the 14 healthy subjects investigated. A follow-on investigation of the effect of exercise-induced sweating on the electrical properties of the electrode-skin-underlying tissue composite during NMES indicated a correlation between the decrease in the resistance values observed over the course of the week and the accumulation of sweat at the electrode-skin interface. The value of the capacitance representing the dielectric properties of the skin's stratum corneum increased after exercise-induced sweating but did not change significantly over the course of the week. We conclude that valuable information about the electrode-skin-underlying tissue composite can be gathered using the NMES signal itself, and suggest that this is a practical, safe and relatively simple method for monitoring these electrical properties during long-term stimulation.
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Affiliation(s)
- S I Bîrlea
- Electrical and Electronic Engineering, School of Engineering and Informatics, NUI Galway, University Road, Galway, Ireland. Bioelectronics Research Cluster, National Centre for Biomedical Engineering Science, NUI Galway, University Road, Galway, Ireland
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McGee MJ, Grill WM. Selective co-stimulation of pudendal afferents enhances bladder activation and improves voiding efficiency. Neurourol Urodyn 2013; 33:1272-8. [PMID: 23934615 DOI: 10.1002/nau.22474] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 07/08/2013] [Indexed: 11/07/2022]
Abstract
AIMS Clinical application of pudendal nerve (PN) afferent stimulation to restore bladder emptying in persons with neurological disorders requires increased stimulation-evoked voiding efficiencies (VEs). We tested the hypothesis that selective co-stimulation of multiple PN branches, either bilateral dorsal nerve of the penis (DNP) stimulation or selective stimulation of both the cranial sensory nerve (CSN) and DNP, will evoke larger reflex bladder contractions and result in higher VEs than stimulation of any single afferent pathway alone. METHODS We measured the strength of bladder contractions, threshold volumes, and VEs produced by unilateral and bilateral stimulation of the DNP as well as singular and selective unilateral co-stimulation of the DNP and CSN in cats anesthetized with α-chloralose. RESULTS Co-stimulation of afferent pathways generated significantly larger isovolumetric bladder contractions and evoked contractions at lower threshold volumes than individual stimulation. Co-stimulation of pudendal afferents also suppressed dyssynergic activity in the external anal sphincter produced by low frequency individual stimulation. VE was significantly improved with co-stimulation (172 ± 6% of distention evoked volumes) over individual stimulation (141 ± 6%). CONCLUSIONS Both types of co-stimulation evoked larger bladder contractions and increased VE over individual branch PN afferent stimulation and distention-evoked voiding. The decreased threshold volumes required for reflex bladder activation and increased VEs with co-stimulation support the use of stimulation of multiple individual stimulation-evoked reflexes to improve voiding efficiency.
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Affiliation(s)
- Meredith J McGee
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
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Collinger JL, Foldes S, Bruns TM, Wodlinger B, Gaunt R, Weber DJ. Neuroprosthetic technology for individuals with spinal cord injury. J Spinal Cord Med 2013; 36:258-72. [PMID: 23820142 PMCID: PMC3758523 DOI: 10.1179/2045772313y.0000000128] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
CONTEXT Spinal cord injury (SCI) results in a loss of function and sensation below the level of the lesion. Neuroprosthetic technology has been developed to help restore motor and autonomic functions as well as to provide sensory feedback. FINDINGS This paper provides an overview of neuroprosthetic technology that aims to address the priorities for functional restoration as defined by individuals with SCI. We describe neuroprostheses that are in various stages of preclinical development, clinical testing, and commercialization including functional electrical stimulators, epidural and intraspinal microstimulation, bladder neuroprosthesis, and cortical stimulation for restoring sensation. We also discuss neural recording technologies that may provide command or feedback signals for neuroprosthetic devices. CONCLUSION/CLINICAL RELEVANCE Neuroprostheses have begun to address the priorities of individuals with SCI, although there remains room for improvement. In addition to continued technological improvements, closing the loop between the technology and the user may help provide intuitive device control with high levels of performance.
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Tator CH, Minassian K, Mushahwar VK. Spinal cord stimulation: therapeutic benefits and movement generation after spinal cord injury. HANDBOOK OF CLINICAL NEUROLOGY 2012; 109:283-296. [PMID: 23098720 DOI: 10.1016/b978-0-444-52137-8.00018-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Spinal cord injury (SCI) is a devastating neurological condition that leads to loss of motor and sensory function. It commonly causes impairments in limb movements, respiration, bowel and bladder function, as well as secondary complications including pain, spasticity, and pressure ulcers. Numerous interventions such as neuroprotection, regeneration, pharmacology, rehabilitation training, and functional electrical stimulation are under investigation for improving function after SCI. This chapter discusses the use of spinal cord stimulation (epidural and intraspinal electrical stimulation) for alleviating pain and spasticity, and restoring standing and walking. Epidural stimulation is effective in reducing the intensity of intractable pain, but its effectiveness in the treatment of spasticity remains unclear. It can induce rhythmic, locomotor-like movements in the legs, presumably due to the activation of afferent pathways. Intraspinal microstimulation is a new electrical stimulation approach that activates locomotor-related networks within the ventral regions of the lumbosacral spinal cord. In animals, this approach is capable of producing prolonged, fatigue-resistant standing and stepping of the hindlegs. While the results in animals have been very encouraging, technical advancements are necessary prior to its implementation in humans with SCI. Taken collectively, spinal cord stimulation holds substantial promise in restoring function after neural injury or disease.
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Affiliation(s)
- Charles H Tator
- Division of Genetics & Development, University of Toronto, Toronto, Canada
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Possover M, Schurch B, Henle KP. New strategies of pelvic nerves stimulation for recovery of pelvic visceral functions and locomotion in paraplegics. Neurourol Urodyn 2011; 29:1433-8. [PMID: 20589714 DOI: 10.1002/nau.20897] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AIMS To present new strategies of pelvic nerves stimulation to enhance micturition, to control spasticity, and to recover locomotion in paraplegics. METHODS Three consecutive patients-Th5, Th7, and Th10 spinal cord injured-underwent laparoscopic transperitoneal implantation of octipolar electrodes to the sciatic and the pudendal nerves and one double extradural Brindley-Finetech electrode bilaterally to the sacral nerve roots S3 and S4. The two octipolar electrodes were connected to an implanted rechargeable generator, while the double Brindley electrode was connected to an implanted Brindley-Finetech receiver block. RESULTS Continuous stimulation of the sciatic and pudendal nerves at a frequency of 20 Hz in all three patients permits complete control of the spasticity of the lower extremities and of reflex incontinence. Bladder emptying is obtained by sacral nerve roots stimulation alone in the first patient, by simple interruption of pudendal stimulation in the second ("pudendal-deblockade") and by simultaneous sacral nerve roots stimulation with high-frequency pudendal nerve blockade in the third patient. Functional electrical stimulation of the femoral nerves enables the Th4 paraplegics lower-limb cycling and the two further patients standing and alternative locomotion. CONCLUSION This short series indicated that laparoscopic implantation of neuroprothesis to the pelvic nerves offers absolutely new strategies based on new combinations of various reported methods to enhance bladder functions and to recover some locomotion in paraplegics.
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Affiliation(s)
- Marc Possover
- Department of Surgical Gynecology & Neuropelveology, Hirslanden Clinic, Zürich, Switzerland.
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Bamford JA, Mushahwar VK. Intraspinal microstimulation for the recovery of function following spinal cord injury. PROGRESS IN BRAIN RESEARCH 2011; 194:227-39. [PMID: 21867807 DOI: 10.1016/b978-0-444-53815-4.00004-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Spinal cord injury is a devastating neurological trauma, often resulting in the impairment of bladder, bowel, and sexual function as well as the loss of voluntary control of muscles innervated by spinal cord segments below the lesion site. Research is ongoing into several classes of therapies to restore lost function. These include the encouragement of neural sparing and regeneration of the affected tissue, and the intervention with pharmacological and rehabilitative means to improve function. This review will focus on the application of electrical current in the spinal cord in order to reactivate extant circuitry which coordinates and controls smooth and skeletal muscle below the injury. We first present a brief historical review of intraspinal microstimulation (ISMS) focusing on its use for restoring bladder function after spinal cord injury as well as its utilization as a research tool for mapping spinal cord circuits that coordinate movements. We then present a review of our own results related to the use of ISMS for restoring standing and walking movements after spinal cord injury. We discuss the mechanisms of action of ISMS and how they relate to observed functional outcomes in animal models. These include the activation of fibers-in-passage which lead to the transsynaptic spread of activation through the spinal cord and the ability of ISMS to produce fatigue-resistant, weight-bearing movements. We present our thoughts on the clinical potential for ISMS with regard to implantation techniques, stability, and damage induced by mechanical and electrical factors. We conclude by suggesting improvements in materials and techniques that are needed in preparation for a clinical proof-of-principle and review our current attempts to achieve these.
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Affiliation(s)
- Jeremy A Bamford
- Department of Cell Biology and the Centre for Neuroscience, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, Canada
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42
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Re-innervation of smooth muscle that is transplanted to provide urethral sphincter augmentation. Auton Neurosci 2011; 159:71-6. [DOI: 10.1016/j.autneu.2010.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 08/11/2010] [Accepted: 08/13/2010] [Indexed: 02/07/2023]
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Mariano TY, Bhadra N, Gustafson KJ. Suppression of reflex urethral responses by sacral dermatome stimulation in an acute spinalized feline model. Neurourol Urodyn 2010; 29:494-500. [PMID: 19283867 DOI: 10.1002/nau.20717] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
AIMS Reflex contractions of the external urethral sphincter (EUS) are a major component of voiding dysfunction after neurological injury or disease. Aberrant urethral reflexes can prevent voiding and cause serious medical complications. Characterizing these urethral reflexes during genitourinary studies is necessary for evaluating novel pharmacological or neuroprosthetic approaches. The objectives of the present study were to generate urethral reflexes in the acute spinal feline, to quantify these reflexes, and to suppress them with electrical stimulation of the sacral dermatomes. METHODS This study comprised eight male cats. Anaesthesia was maintained with alpha-chloralose or sodium pentobarbital. The spinal cord was transected between T10 and T12, and nerve cuff electrodes were placed on the extradural S2 sacral roots to provide bladder activation. Bladder and urethral pressures were recorded during and after bladder contractions. Electrical stimulation was applied non-invasively to the sacral dermatomes with commercial surface electrodes. RESULTS Urethral reflexes were elicited consistently in six cats. The corresponding urethral pressure spikes were quantified. Putative metrics of urethral reflex activity such as the rate and average magnitude of reflex pressure spikes correlated significantly with standard urodynamic variables. Electrical stimulation of the sacral dermatomes suppressed urethral reflexes in three cats. CONCLUSIONS These findings in an acute spinal feline preparation demonstrate a non-invasive means of suppressing undesirable urethral reflexes. Translation of this work to clinical use could improve neuroprostheses for restoring bladder function and enhance treatment of aberrant urethral reflexes in humans.
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Affiliation(s)
- Timothy Y Mariano
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA.
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Furness JB, Shafton AD, Hirst GDS, O'Connell HE. Stimulated smooth muscle neosphincter in male intrinsic sphincter deficiency: Proof of principle studies in a rabbit model. Neurourol Urodyn 2010; 29 Suppl 1:S24-8. [DOI: 10.1002/nau.20835] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Sievert KD, Amend B, Gakis G, Toomey P, Badke A, Kaps HP, Stenzl A. Early sacral neuromodulation prevents urinary incontinence after complete spinal cord injury. Ann Neurol 2010; 67:74-84. [PMID: 20186953 DOI: 10.1002/ana.21814] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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FitzGerald J, Lacour S, McMahon S, Fawcett J. Microchannel Electrodes for Recording and Stimulation:In VitroEvaluation. IEEE Trans Biomed Eng 2009; 56:1524-34. [DOI: 10.1109/tbme.2009.2013960] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Bruns TM, Gustafson KJ, Bhadra N. Reflex bladder activation via pudendal nerve and intraurethral stimulation depends on stimulation pattern and location. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2009; 2008:2760-3. [PMID: 19163277 DOI: 10.1109/iembs.2008.4649774] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Pudendal nerve (PN) stimulation and intraurethral stimulation via a catheter have been demonstrated previously to trigger reflex bladder contractions for 20-40 Hz and 2 & 20 Hz continuous stimuli, respectively. However, thorough studies of the stimulation parameter space and optimal urethral locations are required for translation to clinical feasibility studies for potential neural prostheses. Stimulation-evoked bladder activation was evaluated in fourteen male cats via PN stimulation or intraurethral stimulation before and after spinal transection. In all testing scenarios, the use of pulse bursting led to a greater evoked bladder pressure than with single-pulse continuous waveforms. PN stimulation evoked contractions with 1 Hz and 33 Hz stimuli before spinalization in eight cats. Post-spinalization testing in four cats only elicited excitation for 33 Hz stimuli. For PN stimulation, spinalization eliminated the excitability of low frequency stimulation. Intraurethral stimulation in the proximal and prostatic urethra (2 Hz and 33 Hz range stimuli) and the distal urethra (33 Hz range stimuli) evoked contractions in six cats before spinalization. After spinalization, intraurethral testing in five cats only evoked contractions in the distal and prostatic urethra using 33 Hz range stimuli. For intraurethral stimulation, spinalization eliminated both proximal and low frequency responses. This research improves the knowledge base of several main factors involved in the development of neuroprostheses for bladder control - optimal stimulation paradigms and the understanding of lower urinary tract neurophysiology.
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Affiliation(s)
- Tim M Bruns
- Biomedical Engineering Department, Case Western Reserve University, Cleveland, OH 44106, USA.
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Improved focalization of electrical microstimulation using microelectrode arrays: a modeling study. PLoS One 2009; 4:e4828. [PMID: 19279677 PMCID: PMC2652101 DOI: 10.1371/journal.pone.0004828] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Accepted: 02/11/2009] [Indexed: 11/19/2022] Open
Abstract
Extracellular electrical stimulation (EES) of the central nervous system (CNS) has been used empirically for decades, with both fundamental and clinical goals. Currently, microelectrode arrays (MEAs) offer new possibilities for CNS microstimulation. However, although focal CNS activation is of critical importance to achieve efficient stimulation strategies, the precise spatial extent of EES remains poorly understood. The aim of the present work is twofold. First, we validate a finite element model to compute accurately the electrical potential field generated throughout the extracellular medium by an EES delivered with MEAs. This model uses Robin boundary conditions that take into account the surface conductance of electrode/medium interfaces. Using this model, we determine how the potential field is influenced by the stimulation and ground electrode impedances, and by the electrical conductivity of the neural tissue. We confirm that current-controlled stimulations should be preferred to voltage-controlled stimulations in order to control the amplitude of the potential field. Second, we evaluate the focality of the potential field and threshold-distance curves for different electrode configurations. We propose a new configuration to improve the focality, using a ground surface surrounding all the electrodes of the array. We show that the lower the impedance of this surface, the more focal the stimulation. In conclusion, this study proposes new boundary conditions for the design of precise computational models of extracellular stimulation, and a new electrode configuration that can be easily incorporated into future MEA devices, either in vitro or in vivo, for a better spatial control of CNS microstimulation.
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Gaunt RA, Prochazka A. Transcutaneously coupled, high-frequency electrical stimulation of the pudendal nerve blocks external urethral sphincter contractions. Neurorehabil Neural Repair 2008; 23:615-26. [PMID: 19109445 DOI: 10.1177/1545968308328723] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Detrusor-sphincter dyssynergia is a condition in which reflexive contractions of the external urethral sphincter occur during bladder contractions, preventing the expulsion of urine. High-frequency stimulation (kHz range) has been shown to elicit a fast-acting and reversible block of action potential propagation in peripheral nerves, which may be a useful technique in the management of this condition. OBJECTIVE The aim of these experiments was to see if a newly developed stimulus delivery system, capable of transmitting current transcutaneously to remote peripheral nerves using a passive implanted conductor, was an effective way to transmit high-frequency waveforms to the pudendal nerve to block ongoing sphincter contractions. METHODS High-frequency waveforms were delivered through the skin to the pudendal nerve using a passive implanted conductor in 6 adult cats anesthetized with isoflurane. Five of the experiments were acute, terminal procedures, and the remaining cat was implanted with a permanent electrode system allowing evaluation for 6 months. Typical stimulation parameters were in the range of 1 to 10 kHz and 1 to 10 mA. RESULTS Complete blocking of external urethral sphincter contractions was achieved in 5 of the 6 animals. High-frequency stimulation was also tested in the chronically implanted animal without anesthesia, and the stimulation was tolerated with minimal aversive reactions. CONCLUSIONS The transcutaneous passive implanted conductor stimulus delivery system is an effective way to stimulate the pudendal nerve at high frequency, leading to sphincter relaxation. This system may provide a simple means to implement this stimulation paradigm in people with detrusor-sphincter dyssynergia.
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Affiliation(s)
- Robert A Gaunt
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
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Rajagopalan S, Sawan M, Ghafar-Zadeh E, Savadogo O, Chodavarapu VP. A Polypyrrole-based Strain Sensor Dedicated to Measure Bladder Volume in Patients with Urinary Dysfunction. SENSORS 2008; 8:5081-5095. [PMID: 27873802 PMCID: PMC3705489 DOI: 10.3390/s8085081] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 08/22/2008] [Accepted: 08/26/2008] [Indexed: 11/16/2022]
Abstract
This paper describes a new technique to measure urine volume in patients with urinary bladder dysfunction. Polypyrrole – an electronically conducting polymer - is chemically deposited on a highly elastic fabric. This fabric, when placed around a phantom bladder, produced a reproducible change in electrical resistance on stretching. The resistance response to stretching is linear in 20%-40% strain variation. This change in resistance is influenced by chemical fabrication conditions. We also demonstrate the dynamic mechanical testing of the patterned polypyrrole on fabric in order to show the feasibility of passive interrogation of the strain sensor for biomedical sensing applications.
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Affiliation(s)
- Sumitra Rajagopalan
- Polystim Neurotechnologies Laboratory, Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, Quebec, Canada.
| | - Mohamad Sawan
- Polystim Neurotechnologies Laboratory, Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, Quebec, Canada.
| | - Ebrahim Ghafar-Zadeh
- Polystim Neurotechnologies Laboratory, Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, Quebec, Canada.
- Department of Electrical and Computer Engineering, McGill University, Montréal, Quebec, Canada.
| | - Oumarou Savadogo
- Department of Chemical Engineering, École Polytechnique de Montréal, Montréal, Quebec, Canada.
| | - Vamsy P Chodavarapu
- Department of Electrical and Computer Engineering, McGill University, Montréal, Quebec, Canada.
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