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Su JS, Mazeaud C, Khavari R. Central Nervous Stimulation for Neurogenic Lower Urinary Tract Dysfunction: Current Application and Emergent Therapies. CURRENT BLADDER DYSFUNCTION REPORTS 2023. [DOI: 10.1007/s11884-023-00696-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
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Wulf MJ, Tom VJ. Consequences of spinal cord injury on the sympathetic nervous system. Front Cell Neurosci 2023; 17:999253. [PMID: 36925966 PMCID: PMC10011113 DOI: 10.3389/fncel.2023.999253] [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: 07/20/2022] [Accepted: 02/09/2023] [Indexed: 03/06/2023] Open
Abstract
Spinal cord injury (SCI) damages multiple structures at the lesion site, including ascending, descending, and propriospinal axons; interrupting the conduction of information up and down the spinal cord. Additionally, axons associated with the autonomic nervous system that control involuntary physiological functions course through the spinal cord. Moreover, sympathetic, and parasympathetic preganglionic neurons reside in the spinal cord. Thus, depending on the level of an SCI, autonomic function can be greatly impacted by the trauma resulting in dysfunction of various organs. For example, SCI can lead to dysregulation of a variety of organs, such as the pineal gland, the heart and vasculature, lungs, spleen, kidneys, and bladder. Indeed, it is becoming more apparent that many disorders that negatively affect quality-of-life for SCI individuals have a basis in dysregulation of the sympathetic nervous system. Here, we will review how SCI impacts the sympathetic nervous system and how that negatively impacts target organs that receive sympathetic innervation. A deeper understanding of this may offer potential therapeutic insight into how to improve health and quality-of-life for those living with SCI.
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Affiliation(s)
- Mariah J Wulf
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Veronica J Tom
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States
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Jantz MK, Gopinath C, Kumar R, Chin C, Wong L, Ogren JI, Fisher LE, McLaughlin BL, Gaunt RA. High-density spinal cord stimulation selectively activates lower urinary tract nerves. J Neural Eng 2022; 19:066014. [PMID: 36343359 PMCID: PMC9855651 DOI: 10.1088/1741-2552/aca0c2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/07/2022] [Indexed: 11/09/2022]
Abstract
Objective.Epidural spinal cord stimulation (SCS) is a potential intervention to improve limb and autonomic functions, with lumbar stimulation improving locomotion and thoracic stimulation regulating blood pressure. Here, we asked whether sacral SCS could be used to target the lower urinary tract (LUT) and used a high-density epidural electrode array to test whether individual electrodes could selectively recruit LUT nerves.Approach. We placed a high-density epidural SCS array on the dorsal surface of the sacral spinal cord and cauda equina of anesthetized cats and recorded the stimulation-evoked activity from nerve cuffs on the pelvic, pudendal and sciatic nerves.Main results. Here we show that sacral SCS evokes responses in nerves innervating the bladder and urethra and that these nerves can be activated selectively. Sacral SCS always recruited the pelvic and pudendal nerves and selectively recruited both of these nerves in all but one animal. Individual branches of the pudendal nerve were always recruited as well. Electrodes that selectively recruited specific peripheral nerves were spatially clustered on the arrays, suggesting anatomically organized sensory pathways.Significance.This selective recruitment demonstrates a mechanism to directly modulate bladder and urethral function through known reflex pathways, which could be used to restore bladder and urethral function after injury or disease.
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Affiliation(s)
- Maria K Jantz
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States of America
| | - Chaitanya Gopinath
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Ritesh Kumar
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States of America
| | - Celine Chin
- Micro-Leads Inc., Somerville, MA, United States of America
| | - Liane Wong
- Micro-Leads Inc., Somerville, MA, United States of America
| | - John I Ogren
- Micro-Leads Inc., Somerville, MA, United States of America
| | - Lee E Fisher
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States of America
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States of America
- Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | | | - Robert A Gaunt
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States of America
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States of America
- Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States of America
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Zhong H, Liu E, Kohli P, Perez L, Edgerton VR, Ginsberg D, Gad P, Kreydin E. Noninvasive spinal neuromodulation mitigates symptoms of idiopathic overactive bladder. Bioelectron Med 2022; 8:5. [PMID: 35317851 PMCID: PMC8941742 DOI: 10.1186/s42234-022-00087-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/28/2022] [Indexed: 11/14/2022] Open
Abstract
Background Overactive bladder (OAB) affects 12 to 30% of the world’s population. The accompanying urinary urgency, frequency and incontinence can have a profound effect on quality of life, leading to depression, social isolation, avoidance of sexual activity and loss of productivity. Conservative measures such as lifestyle modification and pelvic floor physical therapy are the first line of treatment for overactive bladder. Patients who fail these may go on to take medications, undergo neuromodulation or receive injection of botulinum toxin into the bladder wall. While effective, medications have side effects and suffer from poor adherence. Neuromodulation and botulinum toxin injection are also effective but are invasive and not acceptable to some patients. Methods We have developed a novel transcutaneous spinal cord neuromodulator (SCONE™,) that delivers multifrequency electrical stimulation to the spinal cord without the need for insertion or implantation of stimulating electrodes. Previously, multifrequency transcutaneous stimulation has been demonstrated to penetrate to the spinal cord and lead to motor activation of detrusor and external urethral sphincter muscles. Here, we report on eight patients with idiopathic overactive bladder, who underwent 12 weeks of SCONE™ therapy. Results All patients reported statistically significant clinical improvement in multiple symptoms of overactive bladder, such as urinary urgency, frequency and urge incontinence. In addition, patients reported significant symptomatic improvements as captured by validated clinical surveys. Conclusion SCONE™ therapy represents the first of its kind therapy to treat symptoms of urgency, frequency and urge urinary incontinence in patients with OAB. Trial registration The study was listed on clinicaltrials.gov (NCT03753750).
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Affiliation(s)
- Hui Zhong
- Department of Neurobiology, University of California, Los Angeles, CA, 90095, USA.,Rancho Research Institute, Rancho Los Amigos National Rehabilitation Center, Downey, CA, 90242, USA
| | - Emilie Liu
- Department of Neurobiology, University of California, Los Angeles, CA, 90095, USA.,Rancho Research Institute, Rancho Los Amigos National Rehabilitation Center, Downey, CA, 90242, USA.,SpineX Inc., 19509 Astor Pl, Northridge, Los Angeles, CA, 91324, USA
| | - Priya Kohli
- Rancho Research Institute, Rancho Los Amigos National Rehabilitation Center, Downey, CA, 90242, USA.,Institute of Urology, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90033, USA
| | - Laura Perez
- Rancho Research Institute, Rancho Los Amigos National Rehabilitation Center, Downey, CA, 90242, USA.,Institute of Urology, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90033, USA
| | - V Reggie Edgerton
- Department of Neurobiology, University of California, Los Angeles, CA, 90095, USA.,Department of Neurosurgery, University of California, Los Angeles, CA, 90095, USA.,Brain Research Institute, University of California, Los Angeles, CA, 90095, USA.,Institut Guttmann, Hospital de Neurorehabilitació, Institut Universitari adscrit a la Universitat Autònoma de Barcelona, 08916, Badalona, Barcelona, Spain
| | - David Ginsberg
- Rancho Research Institute, Rancho Los Amigos National Rehabilitation Center, Downey, CA, 90242, USA.,Institute of Urology, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90033, USA
| | - Parag Gad
- Department of Neurobiology, University of California, Los Angeles, CA, 90095, USA. .,Rancho Research Institute, Rancho Los Amigos National Rehabilitation Center, Downey, CA, 90242, USA. .,SpineX Inc., 19509 Astor Pl, Northridge, Los Angeles, CA, 91324, USA.
| | - Evgeniy Kreydin
- Rancho Research Institute, Rancho Los Amigos National Rehabilitation Center, Downey, CA, 90242, USA.,Institute of Urology, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90033, USA
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Kandhari S, Sharma D, Samuel S, Sharma G, Majumdar P, Edgerton VR, Gad P. Epidural spinal stimulation enables global sensorimotor and autonomic function recovery after complete paralysis: 1st study from India. IEEE Trans Neural Syst Rehabil Eng 2022; 30:2052-2059. [PMID: 35271446 DOI: 10.1109/tnsre.2022.3158393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
While the loss of sensorimotor and autonomic function often occurs due to multiple trauma and pathologies, spinal cord injury is one of the few traumatic pathologies that severely affects multiple organ systems both upstream and downstream of the injury. Current standard of care therapies primarily maintains health and avoids secondary complications. They do not address the underlying neurological condition. Multiple modalities including spinal neuromodulation have shown promise as potential therapies. The objective of this study was to demonstrate the impact of activity-based neurorehabilitation in presence of epidural spinal stimulation to enable simultaneous global recovery of sensorimotor and autonomic functions in patients with complete motor paralysis due to spinal cord injury. These data are unique in that it quantifies simultaneously changes multiple organ systems within only 2 months of intense activity-based neurorehabilitation when also delivering epidural stimulation consisting of sub-motor threshold stimulation over a period of 12-16 hours/day to enable 'self-training' in 10 patients. Finally, these studies were done in a traditional neurorehabilitation clinical in India using off-the-shelf electrode arrays and pulse generators, thus demonstrating the feasibility of this approach in simultaneously enabling recoveries of multiple physiological organ systems after chronic paralysis and the ability to perform these procedures in a standard, well-controlled clinical environment.
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Malone IG, Nosacka RL, Nash MA, Otto KJ, Dale EA. Electrical epidural stimulation of the cervical spinal cord: implications for spinal respiratory neuroplasticity after spinal cord injury. J Neurophysiol 2021; 126:607-626. [PMID: 34232771 DOI: 10.1152/jn.00625.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Traumatic cervical spinal cord injury (cSCI) can lead to damage of bulbospinal pathways to the respiratory motor nuclei and consequent life-threatening respiratory insufficiency due to respiratory muscle paralysis/paresis. Reports of electrical epidural stimulation (EES) of the lumbosacral spinal cord to enable locomotor function after SCI are encouraging, with some evidence of facilitating neural plasticity. Here, we detail the development and success of EES in recovering locomotor function, with consideration of stimulation parameters and safety measures to develop effective EES protocols. EES is just beginning to be applied in other motor, sensory, and autonomic systems; however, there has only been moderate success in preclinical studies aimed at improving breathing function after cSCI. Thus, we explore the rationale for applying EES to the cervical spinal cord, targeting the phrenic motor nucleus for the restoration of breathing. We also suggest cellular/molecular mechanisms by which EES may induce respiratory plasticity, including a brief examination of sex-related differences in these mechanisms. Finally, we suggest that more attention be paid to the effects of specific electrical parameters that have been used in the development of EES protocols and how that can impact the safety and efficacy for those receiving this therapy. Ultimately, we aim to inform readers about the potential benefits of EES in the phrenic motor system and encourage future studies in this area.
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Affiliation(s)
- Ian G Malone
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida.,Breathing Research and Therapeutics Center (BREATHE), University of Florida, Gainesville, Florida
| | - Rachel L Nosacka
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Marissa A Nash
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Kevin J Otto
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida.,Breathing Research and Therapeutics Center (BREATHE), University of Florida, Gainesville, Florida.,J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida.,Department of Neuroscience, University of Florida, Gainesville, Florida.,Department of Neurology, University of Florida, Gainesville, Florida.,Department of Materials Science and Engineering, University of Florida, Gainesville, Florida.,McKnight Brain Institute, University of Florida, Gainesville, Florida
| | - Erica A Dale
- Breathing Research and Therapeutics Center (BREATHE), University of Florida, Gainesville, Florida.,Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida.,Department of Neuroscience, University of Florida, Gainesville, Florida.,McKnight Brain Institute, University of Florida, Gainesville, Florida
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7
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Gad P, Zhong H, Edgerton VR, Kreydin E. Home-Based SCONE TM Therapy Improves Symptoms of Neurogenic Bladder. Neurotrauma Rep 2021; 2:165-168. [PMID: 34223551 PMCID: PMC8240827 DOI: 10.1089/neur.2020.0061] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A wide range of dysfunction can occur after a stroke including symptoms such as urinary urgency, frequency, and urge incontinence. The Spinal Cord Neuromodulator (SCONETM) reactivates and retrains spinal neural networks. The present case study introduces initial evidence that home-based, self-administered SCONE therapy may be a safe and effective method of delivering this neuromodulation modality and may have the ability to minimize clinic visits, which is especially salient in today's public health environment.
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Affiliation(s)
- Parag Gad
- Department of Neurobiology, Keck School of Medicine, University of California, Los Angeles, Los Angeles, California, USA.,Rancho Research Institute, Rancho Los Amigos National Rehabilitation Center, Downey, California, USA.,SpineX, Inc., Los Angeles, California, USA
| | - Hui Zhong
- Department of Neurobiology, Keck School of Medicine, University of California, Los Angeles, Los Angeles, California, USA.,Rancho Research Institute, Rancho Los Amigos National Rehabilitation Center, Downey, California, USA
| | - V Reggie Edgerton
- Department of Neurobiology, Keck School of Medicine, University of California, Los Angeles, Los Angeles, California, USA.,Department of Neurosurgery, Keck School of Medicine, University of California, Los Angeles, Los Angeles, California, USA.,Brain Research Institute, Keck School of Medicine, University of California, Los Angeles, Los Angeles, California, USA.,Institut Guttmann, Hospital de Neurorehabilitació, Institut Universitari adscrit a la Universitat Autònoma de Barcelona, Barcelona, Badalona, Spain
| | - Evgeniy Kreydin
- Department of Neurobiology, Keck School of Medicine, University of California, Los Angeles, Los Angeles, California, USA.,Rancho Research Institute, Rancho Los Amigos National Rehabilitation Center, Downey, California, USA.,Department of Urology, University of Southern California, Los Angeles, California, USA
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8
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Donovan J, Forrest G, Linsenmeyer T, Kirshblum S. Spinal Cord Stimulation After Spinal Cord Injury: Promising Multisystem Effects. CURRENT PHYSICAL MEDICINE AND REHABILITATION REPORTS 2021. [DOI: 10.1007/s40141-020-00304-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Herrity AN, Aslan SC, Ugiliweneza B, Mohamed AZ, Hubscher CH, Harkema SJ. Improvements in Bladder Function Following Activity-Based Recovery Training With Epidural Stimulation After Chronic Spinal Cord Injury. Front Syst Neurosci 2021; 14:614691. [PMID: 33469421 PMCID: PMC7813989 DOI: 10.3389/fnsys.2020.614691] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 12/03/2020] [Indexed: 12/27/2022] Open
Abstract
Spinal cord injury (SCI) results in profound neurologic impairment with widespread deficits in sensorimotor and autonomic systems. Voluntary and autonomic control of bladder function is disrupted resulting in possible detrusor overactivity, low compliance, and uncoordinated bladder and external urethral sphincter contractions impairing storage and/or voiding. Conservative treatments managing neurogenic bladder post-injury, such as oral pharmacotherapy and catheterization, are important components of urological surveillance and clinical care. However, as urinary complications continue to impact long-term morbidity in this population, additional therapeutic and rehabilitative approaches are needed that aim to improve function by targeting the recovery of underlying impairments. Several human and animal studies, including our previously published reports, have documented gains in bladder function due to activity-based recovery strategies, such as locomotor training. Furthermore, epidural stimulation of the spinal cord (scES) combined with intense activity-based recovery training has been shown to produce volitional lower extremity movement, standing, as well as improve the regulation of cardiovascular function. In our center, several participants anecdotally reported improvements in bladder function as a result of training with epidural stimulation configured for motor systems. Thus, in this study, the effects of activity-based recovery training in combination with scES were tested on bladder function, resulting in improvements in overall bladder storage parameters relative to a control cohort (no intervention). However, elevated blood pressure elicited during bladder distention, characteristic of autonomic dysreflexia, was not attenuated with training. We then examined, in a separate, large cross-sectional cohort, the interaction between detrusor pressure and blood pressure at maximum capacity, and found that the functional relationship between urinary bladder distention and blood pressure regulation is disrupted. Regardless of one’s bladder emptying method (indwelling suprapubic catheter vs. intermittent catheterization), autonomic instability can play a critical role in the ability to improve bladder storage, with SCI enhancing the vesico-vascular reflex. These results support the role of intersystem stimulation, integrating scES for both bladder and cardiovascular function to further improve bladder storage.
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Affiliation(s)
- April N Herrity
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States.,Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Sevda C Aslan
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States.,Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Beatrice Ugiliweneza
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States.,Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Ahmad Z Mohamed
- Department of Urology, University of Louisville, Louisville, KY, United States
| | - Charles H Hubscher
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States.,Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY, United States
| | - Susan J Harkema
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States.,Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
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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: 5] [Impact Index Per Article: 1.3] [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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11
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Granger N, Olby NJ, Nout-Lomas YS. Bladder and Bowel Management in Dogs With Spinal Cord Injury. Front Vet Sci 2020; 7:583342. [PMID: 33263015 PMCID: PMC7686579 DOI: 10.3389/fvets.2020.583342] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/22/2020] [Indexed: 11/13/2022] Open
Abstract
Spinal cord injury in companion dogs can lead to urinary and fecal incontinence or retention, depending on the severity, and localization of the lesion along the canine nervous system. The bladder and gastrointestinal dysfunction caused by lesions of the autonomic system can be difficult to recognize, interpret and are easily overlooked. Nevertheless, it is crucial to maintain a high degree of awareness of the impact of micturition and defecation disturbances on the animal's condition, welfare and on the owner. The management of these disabilities is all the more challenging that the autonomic nervous system physiology is a complex topic. In this review, we propose to briefly remind the reader the physiology of micturition and defecation in dogs. We then present the bladder and gastrointestinal clinical signs associated with sacral lesions (i.e., the L7-S3 spinal cord segments and nerves) and supra-sacral lesions (i.e., cranial to the L7 spinal cord segment), largely in the context of intervertebral disc herniation. We summarize what is known about the natural recovery of urinary and fecal continence in dogs after spinal cord injury. In particular we review the incidence of urinary tract infection after injury. We finally explore the past and recent literature describing management of urinary and fecal dysfunction in the acute and chronic phase of spinal cord injury. This comprises medical therapies but importantly a number of surgical options, some known for decades such as sacral nerve stimulation, that might spark some interest in the field of spinal cord injury in companion dogs.
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Affiliation(s)
- Nicolas Granger
- The Royal Veterinary College, University of London, Hertfordshire, United Kingdom.,CVS Referrals, Bristol Veterinary Specialists at Highcroft, Bristol, United Kingdom
| | - Natasha J Olby
- Department of Clinical Sciences, North Carolina State University College of Veterinary Medicine, Raleigh, NC, United States
| | - Yvette S Nout-Lomas
- Department of Clinical Sciences, Colorado State University, Fort Collins, CO, United States
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12
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Spinal cord stimulation and rehabilitation in an individual with chronic complete L1 paraplegia due to a conus medullaris injury: motor and functional outcomes at 18 months. Spinal Cord Ser Cases 2020; 6:96. [PMID: 33067413 DOI: 10.1038/s41394-020-00345-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 09/15/2020] [Accepted: 09/21/2020] [Indexed: 02/07/2023] Open
Abstract
INTRODUCTION Epidural electrical stimulation of the conus medullaris has helped facilitate native motor recovery in individuals with complete cervicothoracic spinal cord injuries (SCI). A theorized mechanism of clinical improvement includes supporting central pattern generators intrinsic to the conus medullaris. Because spinal cord stimulators (SCS) are approved for the treatment of neuropathic pain, we were able to test this experimental therapy in a subject with complete L1 paraplegia and neuropathic genital pain due to a traumatic conus injury. CASE PRESENTATION An otherwise healthy 48-year-old male with chronic complete L1 paraplegia with no zones of partial preservation (ZPP) and intractable neuropathic genital pain presented to our group seeking nonmedical pain relief and any possible help with functional restoration. After extensive evaluation, discussion, and consent, we proceeded with SCS implantation at the conus and an intensive outpatient physical therapy regimen consistent with the recent SCI rehabilitation literature. DISCUSSION Intraoperatively, no electromyography (EMG) could be elicited with epidural conus stimulation. At 18 months after implantation, his motor ZPPs had advanced from L1 to L5 on the left and from L1 to L3 on the right. Qualitative increases in lower extremity resting state EMG amplitudes were noted, although there was no consistent evidence of voluntary EMG or rhythmic locomotive leg movements. Three validated functional and quality of life (QoL) surveys demonstrated substantial improvements. The modest motor response compared to the literature suggests likely critical differences in the anatomy of such a low injury. However, the change in ZPPs and QoL suggest potential for neuroplasticity even in this patient population.
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Bourbeau D, Creasey G, French J, Grill WM, Howley S, Krassioukov A, Moritz C, Santacruz B, Thor K, Wheeler T. A roadmap for advancing neurostimulation approaches for bladder and bowel function after spinal cord injury. Spinal Cord 2020; 58:1227-1232. [PMID: 32895476 DOI: 10.1038/s41393-020-00544-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 08/21/2020] [Accepted: 08/26/2020] [Indexed: 11/09/2022]
Affiliation(s)
- Dennis Bourbeau
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, USA. .,MetroHealth Medical System, Cleveland, OH, USA.
| | | | | | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Susan Howley
- Christopher and Dana Reeve Foundation, New York, NY, USA
| | - Andrei Krassioukov
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
| | - Chet Moritz
- Departments of Electrical and Computer Engineering, Rehabilitation Medicine, and Physiology & Biophysics, Center for Neurotechnology, University of Washington, Seattle, WA, USA
| | | | - Karl Thor
- Dignify Therapeutics Inc., Durham, NC, USA
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14
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Eisdorfer JT, Smit RD, Keefe KM, Lemay MA, Smith GM, Spence AJ. Epidural Electrical Stimulation: A Review of Plasticity Mechanisms That Are Hypothesized to Underlie Enhanced Recovery From Spinal Cord Injury With Stimulation. Front Mol Neurosci 2020; 13:163. [PMID: 33013317 PMCID: PMC7497436 DOI: 10.3389/fnmol.2020.00163] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 08/07/2020] [Indexed: 12/17/2022] Open
Abstract
Spinal cord injury (SCI) often results in life-long sensorimotor impairment. Spontaneous recovery from SCI is limited, as supraspinal fibers cannot spontaneously regenerate to form functional networks below the level of injury. Despite this, animal models and humans exhibit many motor behaviors indicative of recovery when electrical stimulation is applied epidurally to the dorsal aspect of the lumbar spinal cord. In 1976, epidural stimulation was introduced to alleviate spasticity in Multiple Sclerosis. Since then, epidural electrical stimulation (EES) has been demonstrated to improve voluntary mobility across the knee and/or ankle in several SCI patients, highlighting its utility in enhancing motor activation. The mechanisms that EES induces to drive these improvements in sensorimotor function remain largely unknown. In this review, we discuss several sensorimotor plasticity mechanisms that we hypothesize may enable epidural stimulation to promote recovery, including changes in local lumbar circuitry, propriospinal interneurons, and the internal model. Finally, we discuss genetic tools for afferent modulation as an emerging method to facilitate the search for the mechanisms of action.
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Affiliation(s)
- Jaclyn T Eisdorfer
- Department of Bioengineering, College of Engineering, Temple University, Philadelphia, PA, United States
| | - Rupert D Smit
- Department of Neuroscience, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Kathleen M Keefe
- Department of Bioengineering, College of Engineering, Temple University, Philadelphia, PA, United States
| | - Michel A Lemay
- Department of Bioengineering, College of Engineering, Temple University, Philadelphia, PA, United States
| | - George M Smith
- Department of Neuroscience, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Andrew J Spence
- Department of Bioengineering, College of Engineering, Temple University, Philadelphia, PA, United States
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15
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Sysoev Y, Bazhenova E, Lyakhovetskii V, Kovalev G, Shkorbatova P, Islamova R, Pavlova N, Gorskii O, Merkulyeva N, Shkarupa D, Musienko P. Site-Specific Neuromodulation of Detrusor and External Urethral Sphincter by Epidural Spinal Cord Stimulation. Front Syst Neurosci 2020; 14:47. [PMID: 32774243 PMCID: PMC7387722 DOI: 10.3389/fnsys.2020.00047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 06/26/2020] [Indexed: 12/18/2022] Open
Abstract
Impairments of the lower urinary tract function including urine storage and voiding are widely spread among patients with spinal cord injuries. The management of such patients includes bladder catheterization, surgical and pharmacological approaches, which reduce the morbidity from urinary tract-related complications. However, to date, there is no effective treatment of neurogenic bladder and restoration of urinary function. In the present study, we examined neuromodulation of detrusor (Detr) and external urethral sphincter by epidural electrical stimulation (EES) of lumbar and sacral regions of the spinal cord in chronic rats. To our knowledge, it is the first chronic study where detrusor and external urethral sphincter signals were recorded simultaneously to monitor their neuromodulation by site-specific spinal cord stimulation (SCS). The data obtained demonstrate that activation of detrusor muscle mainly occurs during the stimulation of the upper lumbar (L1) and lower lumbar (L5-L6) spinal segments whereas external urethral sphincter was activated predominantly by sacral stimulation. These findings can be used for the development of neurorehabilitation strategies based on spinal cord epidural stimulation for autonomic function recovery after severe spinal cord injury (SCI).
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Affiliation(s)
- Yuriy Sysoev
- Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Russia.,Department of Pharmacology and Clinical Pharmacology, Saint-Petersburg State Chemical Pharmaceutical University, Saint-Petersburg, Russia
| | - Elena Bazhenova
- Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Russia.,Pavlov Institute of Physiology, Russian Academy of Sciences (RAS), Saint-Petersburg, Russia
| | - Vsevolod Lyakhovetskii
- Pavlov Institute of Physiology, Russian Academy of Sciences (RAS), Saint-Petersburg, Russia.,Granov Russian Research Center of Radiology and Surgical Technologies, Ministry of Healthcare of the Russian Federation, Saint-Petersburg, Russia
| | - Gleb Kovalev
- Clinic of High Medical Technology named after N.I. Pirogov St. Petersburg State University, Saint-Petersburg, Russia
| | - Polina Shkorbatova
- Pavlov Institute of Physiology, Russian Academy of Sciences (RAS), Saint-Petersburg, Russia
| | - Regina Islamova
- Institute of Chemistry, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Natalia Pavlova
- Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Russia.,Pavlov Institute of Physiology, Russian Academy of Sciences (RAS), Saint-Petersburg, Russia
| | - Oleg Gorskii
- Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Russia.,Pavlov Institute of Physiology, Russian Academy of Sciences (RAS), Saint-Petersburg, Russia.,Granov Russian Research Center of Radiology and Surgical Technologies, Ministry of Healthcare of the Russian Federation, Saint-Petersburg, Russia
| | - Natalia Merkulyeva
- Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Russia.,Pavlov Institute of Physiology, Russian Academy of Sciences (RAS), Saint-Petersburg, Russia.,Granov Russian Research Center of Radiology and Surgical Technologies, Ministry of Healthcare of the Russian Federation, Saint-Petersburg, Russia
| | - Dmitry Shkarupa
- Clinic of High Medical Technology named after N.I. Pirogov St. Petersburg State University, Saint-Petersburg, Russia
| | - Pavel Musienko
- Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Russia.,Pavlov Institute of Physiology, Russian Academy of Sciences (RAS), Saint-Petersburg, Russia.,Granov Russian Research Center of Radiology and Surgical Technologies, Ministry of Healthcare of the Russian Federation, Saint-Petersburg, Russia.,Saint-Petersburg State Research Institute of Phthisiopulmonology, Ministry of Healthcare of the Russian Federation, Saint-Petersburg, Russia
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16
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Changes in spinal cord hemodynamics reflect modulation of spinal network with different parameters of epidural stimulation. Neuroimage 2020; 221:117183. [PMID: 32702485 PMCID: PMC7802109 DOI: 10.1016/j.neuroimage.2020.117183] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 06/04/2020] [Accepted: 07/16/2020] [Indexed: 11/29/2022] Open
Abstract
In this study functional ultrasound (fUS) imaging has been implemented to explore the local hemodynamics response induced by electrical epidural stimulation and to study real-time in vivo functional changes of the spinal cord, taking advantage of the superior spatiotemporal resolution provided by fUS. By quantifying the hemodynamics and electromyographic response features, we tested the hypothesis that the temporal hemodynamics response of the spinal cord to electrical epidural stimulation could reflect modulation of the spinal circuitry and accordingly respond to the changes in parameters of electrical stimulation. The results of this study for the first time demonstrate that the hemodynamics response to electrical stimulation could reflect a neural-vascular coupling of the spinal cord. Response in the dorsal areas to epidural stimulation was significantly higher and faster compared to the response in ventral spinal cord. Positive relation between the hemodynamics and the EMG responses was observed at the lower frequencies of epidural stimulation (20 and 40 Hz), which according to our previous findings can facilitate spinal circuitry after spinal cord injury, compared to higher frequencies (200 and 500 Hz). These findings suggest that different mechanisms could be involved in spinal cord hemodynamics changes during different parameters of electrical stimulation and for the first time provide the evidence that neural-vascular coupling of the spinal cord circuitry could be related to specific organization of spinal cord vasculature and hemodynamics.
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17
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Steadman CJ, Grill WM. Spinal cord stimulation for the restoration of bladder function after spinal cord injury. Healthc Technol Lett 2020; 7:87-92. [PMID: 32754343 PMCID: PMC7353924 DOI: 10.1049/htl.2020.0026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/15/2020] [Accepted: 05/15/2020] [Indexed: 12/20/2022] Open
Abstract
Spinal cord injury (SCI) results in the inability to empty the bladder voluntarily, and neurogenic detrusor overactivity (NDO) and detrusor sphincter dyssynergia (DSD) negatively impact both the health and quality of life of persons with SCI. Current approaches to treat bladder dysfunction in persons with SCI, including self-catheterisation and anticholinergic medications, are inadequate, and novel approaches are required to restore continence with increased bladder capacity, as well as to provide predictable and efficient on-demand voiding. Improvements in bladder function following SCI have been documented using a number of different modalities of spinal cord stimulation (SCS) in both persons with SCI and animal models, including SCS alone or SCS with concomitant activity-based training. Improvements include increased volitional voiding, voided volumes, bladder capacity, and quality of life, as well as decreases in NDO and DSD. Further, SCS is a well-developed therapy for chronic pain, and existing Food And Drug Administration (FDA)-approved devices provide a clear pathway to sustainable commercial availability and impact. However, the effective stimulation parameters and the appropriate timing and location of stimulation for SCS-mediated restoration of bladder function require further study, and studies are needed to determine underlying mechanisms of action.
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Affiliation(s)
- Casey J Steadman
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA.,Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA.,Department of Neurobiology, Duke University, Durham, NC 27708, USA.,Department of Neurosurgery, Duke University, Durham, NC 27708, USA
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18
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Gad P, Lee S, Terrafranca N, Zhong H, Turner A, Gerasimenko Y, Edgerton VR. Non-Invasive Activation of Cervical Spinal Networks after Severe Paralysis. J Neurotrauma 2019; 35:2145-2158. [PMID: 29649928 DOI: 10.1089/neu.2017.5461] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Paralysis of the upper extremities following cervical spinal cord injury (SCI) significantly impairs one's ability to live independently. While regaining hand function or grasping ability is considered one of the most desired functions in tetraplegics, limited therapeutic development in this direction has been demonstrated to date in humans with a high severe cervical injury. The underlying hypothesis is that after severe cervical SCI, nonfunctional sensory-motor networks within the cervical spinal cord can be transcutaneously neuromodulated to physiological states that enable and amplify voluntary control of the hand. Improved voluntary hand function occurred within a single session in every subject tested. After eight sessions of non-invasive transcutaneous stimulation, combined with training over 4 weeks, maximum voluntary hand grip forces increased by ∼325% (in the presence of stimulation) and ∼225% (when grip strength was tested without simultaneous stimulation) in chronic cervical SCI subjects (American Spinal Injury Association Impairment Scale [AIS] B, n = 3; AIS C, n = 5) 1-21 years post-injury). Maximum grip strength improved in both the left and right hands and the magnitude of increase was independent of hand dominance. We refer to the neuromodulatory method used as transcutaneous enabling motor control to emphasize that the stimulation parameters used are designed to avoid directly inducing muscular contractions, but to enable task performance according to the subject's voluntary intent. In some subjects, there were improvements in autonomic function, lower extremity motor function, and sensation below the level of the lesion. Although a neuromodulation-training effect was observed in every subject tested, further controlled and blinded studies are needed to determine the responsiveness of a larger and broader population of subjects varying in the type, severity, and years post-injury. It appears rather convincing, however, that a "central pattern generation" phenomenon as generally perceived in the lumbosacral networks in controlling stepping neuromodulator is not a critical element of spinal neuromodulation to regain function among spinal networks.
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Affiliation(s)
- Parag Gad
- 1 Department of Integrative Biology and Physiology, University of California , Los Angeles, California
| | - Sujin Lee
- 2 Veterans Affair Healthcare System Spinal Cord Injury and Disorders Center , Long Beach, California
| | | | - Hui Zhong
- 1 Department of Integrative Biology and Physiology, University of California , Los Angeles, California
| | - Amanda Turner
- 1 Department of Integrative Biology and Physiology, University of California , Los Angeles, California
| | - Yury Gerasimenko
- 1 Department of Integrative Biology and Physiology, University of California , Los Angeles, California.,4 Pavlov Institute of Physiology , St. Petersburg, Russia .,10 Institute of Fundamental Medicine and Biology, Kazan Federal University , Kazan, Russia
| | - V Reggie Edgerton
- 1 Department of Integrative Biology and Physiology, University of California , Los Angeles, California.,5 Department of Neurobiology, University of California , Los Angeles, California.,6 Department of Neurosurgery, University of California , Los Angeles, California.,7 Brain Research Institute, University of California , Los Angeles, California.,8 Institut Guttmann. Hospital de Neurorehabilitació, Institut Universitari adscrit a la Universitat Autònoma de Barcelona , Barcelona, Spain .,9 The Centre for Neuroscience and Regenerative Medicine, University of Technology Sydney , Ultimo, Australia
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19
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Savenkova AA, Sarana AM, Shcherbak SG, Gerasimenko YP, Moshonkina TR. [Noninvasive spinal cord electrical stimulation in the complex rehabilitation of patients with spinal cord injury]. VOPROSY KURORTOLOGII, FIZIOTERAPII, I LECHEBNOĬ FIZICHESKOĬ KULTURY 2019; 96:11-18. [PMID: 31626155 DOI: 10.17116/kurort20199605111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Spinal cord injury causes significant impairments of both motor and pelvic organ functions. Latest studies have shown impressive potentials for using transcutaneous spinal cord electrical stimulation (TcSCES) in the late period of injury to restore motor functions. All results were obtained in a limited number of patients in the specific conditions of a physiological experiment. It remains unclear how effective a TcSCES cycle is in restoring motor activity in patients after spinal cord injury in real clinical conditions. AIM The main objective of this investigation was to study the effectiveness of TcSCES in combination with the standard rehabilitation of patients after a spinal cord injury. An additional objective was to evaluate the effect of TcSCES to excretory functions in patients with spinal cord injury. SUBJECTS AND METHODS The studies were conducted at Saint Petersburg City Hospital Forty, which included 15 patients with thoracic spinal injury at 2.4±2.06 years after injury; the severity of the latter was American Spinal Injury Association (ASIA) Grades B and C. All the patients underwent a 2-week standard cycle of rehabilitation treatment; of them 7 patients (a study group) received additionally TcSCES. Standard scales were used to assess neurological status and muscle strength and sensitivity. The patients filled out a urinary diary; residual urine volume was monitored using bladder catheterization or ultrasound. RESULTS An increase in muscle strength was recorded in 6 patients of the study group and in 1 patient of the control one. The end of the treatment cycle was marked by a 1-score spasticity increase in 1 patient of the study group and in 2 patients in the control one. In the study group, the level of anesthesia decreased per segment in 1 patient; an improvement in deep and proprioceptive sensitivity was recorded in 2 patients; no change in sensitivity was observed in the control group. In the study group, 2 patients showed a reduction in the severity of injury from ASIA Grade B to ASIA Grade C. In three patients of the study group, the residual urine volume decreased and control and a sensation of urgency to urinate appeared; in the control group, these parameters remained unchanged after the treatment cycle. DISCUSSION The main result of the study is evidence for the efficiency of using TcSCES in the complex therapy of motor neurorehabilitation. The performed cycle of TcSCES in patients was noted to result in better motor and excretory functions. CONCLUSION The use of a short-term TcSCES cycle in the motor rehabilitation program for patients with spinal cord injury contributes to recovery of severe motor disorders and is accompanied by an improvement in urinary functions.
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Affiliation(s)
| | - A M Sarana
- City Hospital Forty, Saint Petersburg, Russia; Saint Petersburg State University, Saint Petersburg, Russia
| | - S G Shcherbak
- City Hospital Forty, Saint Petersburg, Russia; Saint Petersburg State University, Saint Petersburg, Russia
| | - Yu P Gerasimenko
- I.P. Pavlov Institute of Physiology, Russian Academy of Sciences, Saint Petersburg, Russia
| | - T R Moshonkina
- I.P. Pavlov Institute of Physiology, Russian Academy of Sciences, Saint Petersburg, Russia
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20
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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: 31] [Impact Index Per Article: 6.2] [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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21
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Noninvasive spinal neuromodulation to map and augment lower urinary tract function in rhesus macaques. Exp Neurol 2019; 322:113033. [PMID: 31400304 DOI: 10.1016/j.expneurol.2019.113033] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 07/15/2019] [Accepted: 08/06/2019] [Indexed: 12/25/2022]
Abstract
Dysfunction of the lower urinary tract (LUT) is prevalent in neurological disorders, including multiple sclerosis, stroke, spinal cord injury and neurodegenerative conditions. Common symptoms include urgency, incontinence, and urinary retention. Recent advances in neuromodulation have resulted in improved treatments for overactive bladder symptoms of urgency, frequency, and nocturia. However, there are presently no treatments available for the induction of voiding to overcome urinary retention. We demonstrate that transcutaneous spinal cord stimulation (TSCS), a non-invasive intervention, applied over the thoracolumbar spine in neurologically intact rhesus macaques can activate the LUT, including activation of the bladder detrusor muscle, the urethral sphincter and pelvic floor muscles. Urodynamic studies show improved voiding efficiency and decreased post-voiding residual volumes in the bladder, while maintaining coordinated activity in the detrusor and sphincter with physiologic detrusor peak pressure, contraction duration, and urine flow rate remaining unchanged. We conclude that TSCS may represent a novel approach to activate the LUT and enable voiding in select neurological conditions.
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22
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Merkulyeva N, Lyakhovetskii V, Veshchitskii A, Bazhenova E, Gorskii O, Musienko P. Activation of the spinal neuronal network responsible for visceral control during locomotion. Exp Neurol 2019; 320:112986. [PMID: 31254518 DOI: 10.1016/j.expneurol.2019.112986] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 05/19/2019] [Accepted: 06/25/2019] [Indexed: 12/21/2022]
Abstract
It has been established that stepping of the decerebrate cat was accompanied by involvement of the urinary system: external urethral sphincter (EUS) and detrusor muscle activation, as well as the corresponding increase of the intravesical pressure. Detrusor and EUS evoked EMG activity matched the limbs locomotor movements. Immunohistochemical labeling of the immediate early gene c-fos expression was used to reveal the neural mechanisms of such somatovisceral interconnection within the sacral neural pathways. Study showed that two locomotor modes (forward and backward walking) had significantly different kinematic features. Combining the different immunohistochemical methods, we found that many c-fos-immunopositive nuclei were localized within several visceral areas of the S2 spinal segment which matched the sacral parasympathetic nucleus and dorsal gray commissure. Cats stepping backward had 4-fold more c-fos-immunopositive nuclei within the ventrolateral part of the sacral parasympathetic nucleus apparently correspondent to the "lateral band" contained cells controlling bladder function. The present work provides the direct evidences of visceral neurons activation depending on the specific of locomotor pattern and confirms the somatovisceral integration carrying out on the spinal cord level.
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Affiliation(s)
- Natalia Merkulyeva
- Pavlov Institute of Physiology RAS, Saint-Petersburg, Makarov emb., 6, 199034, Russia; Russian Research Center of Radiology and Surgical Technologies, Ministry of Health of the RF, Saint-Petersburg, poselok Pesochnyy, Leningradskaya str., 70, 197758, Russia; Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Universitetskaya emb., 7-9, 199034, Russia
| | - Vsevolod Lyakhovetskii
- Pavlov Institute of Physiology RAS, Saint-Petersburg, Makarov emb., 6, 199034, Russia; Russian Research Center of Radiology and Surgical Technologies, Ministry of Health of the RF, Saint-Petersburg, poselok Pesochnyy, Leningradskaya str., 70, 197758, Russia
| | | | - Elena Bazhenova
- Pavlov Institute of Physiology RAS, Saint-Petersburg, Makarov emb., 6, 199034, Russia; Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Universitetskaya emb., 7-9, 199034, Russia
| | - Oleg Gorskii
- Pavlov Institute of Physiology RAS, Saint-Petersburg, Makarov emb., 6, 199034, Russia; Russian Research Center of Radiology and Surgical Technologies, Ministry of Health of the RF, Saint-Petersburg, poselok Pesochnyy, Leningradskaya str., 70, 197758, Russia; Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Universitetskaya emb., 7-9, 199034, Russia
| | - Pavel Musienko
- Pavlov Institute of Physiology RAS, Saint-Petersburg, Makarov emb., 6, 199034, Russia; Russian Research Center of Radiology and Surgical Technologies, Ministry of Health of the RF, Saint-Petersburg, poselok Pesochnyy, Leningradskaya str., 70, 197758, Russia; Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Universitetskaya emb., 7-9, 199034, Russia; Children's Surgery and Orthopedic Clinic, Department of Non-pulmonary Tuberculosis, Research Institute of Phthysiopulmonology, Saint-Petersburg, Politekhnicheskaya str., 32, 194064, Russia.
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23
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Calvert JS, Grahn PJ, Zhao KD, Lee KH. Emergence of Epidural Electrical Stimulation to Facilitate Sensorimotor Network Functionality After Spinal Cord Injury. Neuromodulation 2019; 22:244-252. [PMID: 30840354 DOI: 10.1111/ner.12938] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 01/15/2019] [Accepted: 01/19/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND Traumatic spinal cord injury (SCI) disrupts signaling pathways between the brain and spinal networks below the level of injury. In cases of severe SCI, permanent loss of sensorimotor and autonomic function can occur. The standard of care for severe SCI uses compensation strategies to maximize independence during activities of daily living while living with chronic SCI-related dysfunctions. Over the past several years, the research field of spinal neuromodulation has generated promising results that hold potential to enable recovery of functions via epidural electrical stimulation (EES). METHODS This review provides a historical account of the translational research efforts that led to the emergence of EES of the spinal cord to enable intentional control of motor functions that were lost after SCI. We also highlight the major limitations associated with EES after SCI and propose future directions of spinal neuromodulation research. RESULTS Multiple, independent studies have demonstrated return of motor function via EES in individuals with chronic SCI. These enabled motor functions include intentional, controlled movement of previously paralyzed extremities, independent standing and stepping, and increased grip strength. In addition, improvements in cardiovascular health, respiratory function, body composition, and urologic function have been reported. CONCLUSIONS EES holds promise to enable functions thought to be permanently lost due to SCI. However, EES is currently restricted to scientific investigation in humans with SCI and requires further validation of factors such as safety and efficacy before clinical translation.
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Affiliation(s)
| | - Peter J Grahn
- Department of Neurologic Surgery, Rochester, MN, USA.,Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Rochester, MN, USA
| | - Kristin D Zhao
- Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Rochester, MN, USA.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Kendall H Lee
- Department of Neurologic Surgery, Rochester, MN, USA.,Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Rochester, MN, USA.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
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24
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Calvert JS, Grahn PJ, Strommen JA, Lavrov IA, Beck LA, Gill ML, Linde MB, Brown DA, Van Straaten MG, Veith DD, Lopez C, Sayenko DG, Gerasimenko YP, Edgerton VR, Zhao KD, Lee KH. Electrophysiological Guidance of Epidural Electrode Array Implantation over the Human Lumbosacral Spinal Cord to Enable Motor Function after Chronic Paralysis. J Neurotrauma 2018; 36:1451-1460. [PMID: 30430902 PMCID: PMC6482916 DOI: 10.1089/neu.2018.5921] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Epidural electrical stimulation (EES) of the spinal cord has been shown to restore function after spinal cord injury (SCI). Characterization of EES-evoked motor responses has provided a basic understanding of spinal sensorimotor network activity related to EES-enabled motor activity of the lower extremities. However, the use of EES-evoked motor responses to guide EES system implantation over the spinal cord and their relation to post-operative EES-enabled function in humans with chronic paralysis attributed to SCI has yet to be described. Herein, we describe the surgical and intraoperative electrophysiological approach used, followed by initial EES-enabled results observed in 2 human subjects with motor complete paralysis who were enrolled in a clinical trial investigating the use of EES to enable motor functions after SCI. The 16-contact electrode array was initially positioned under fluoroscopic guidance. Then, EES-evoked motor responses were recorded from select leg muscles and displayed in real time to determine electrode array proximity to spinal cord regions associated with motor activity of the lower extremities. Acceptable array positioning was determined based on achievement of selective proximal or distal leg muscle activity, as well as bilateral muscle activation. Motor response latencies were not significantly different between intraoperative recordings and post-operative recordings, indicating that array positioning remained stable. Additionally, EES enabled intentional control of step-like activity in both subjects within the first 5 days of testing. These results suggest that the use of EES-evoked motor responses may guide intraoperative positioning of epidural electrodes to target spinal cord circuitry to enable motor functions after SCI.
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Affiliation(s)
- Jonathan S Calvert
- 1 Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, Minnesota
| | - Peter J Grahn
- 2 Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota
| | - Jeffrey A Strommen
- 3 Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Mayo Clinic, Rochester, Minnesota
| | - Igor A Lavrov
- 2 Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota
| | - Lisa A Beck
- 3 Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Mayo Clinic, Rochester, Minnesota
| | - Megan L Gill
- 3 Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Mayo Clinic, Rochester, Minnesota
| | - Margaux B Linde
- 3 Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Mayo Clinic, Rochester, Minnesota
| | - Desmond A Brown
- 2 Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota
| | - Meegan G Van Straaten
- 3 Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Mayo Clinic, Rochester, Minnesota
| | - Daniel D Veith
- 3 Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Mayo Clinic, Rochester, Minnesota
| | - Cesar Lopez
- 3 Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Mayo Clinic, Rochester, Minnesota
| | - Dimitry G Sayenko
- 4 Department of Integrative Biology and Physiology University of California Los Angeles, Los Angeles, California.,12 Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, Texas
| | - Yury P Gerasimenko
- 4 Department of Integrative Biology and Physiology University of California Los Angeles, Los Angeles, California.,5 Pavlov Institute of Physiology, St. Petersburg, Russia
| | - V Reggie Edgerton
- 4 Department of Integrative Biology and Physiology University of California Los Angeles, Los Angeles, California.,6 Department of Neurobiology, University of California Los Angeles, Los Angeles, California.,7 Department of Neurosurgery, University of California Los Angeles, Los Angeles, California.,8 Brain Research Institute, University of California Los Angeles, Los Angeles, California.,9 Institut Guttmann, Hospital de Neurorehabilitació, Institut Universitari adscrit a la Universitat Autònoma de Barcelona, Barcelona, Badalona, Spain.,10 Centre for Neuroscience and Regenerative Medicine, Faculty of Science, University of Technology Sydney, Ultimo, New South Wales, Australia
| | - Kristin D Zhao
- 3 Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Mayo Clinic, Rochester, Minnesota.,11 Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Kendall H Lee
- 2 Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota.,3 Department of Physical Medicine and Rehabilitation, Rehabilitation Medicine Research Center, Mayo Clinic, Rochester, Minnesota.,11 Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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25
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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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26
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A Proof-of-Concept Study of Transcutaneous Magnetic Spinal Cord Stimulation for Neurogenic Bladder. Sci Rep 2018; 8:12549. [PMID: 30135433 PMCID: PMC6105631 DOI: 10.1038/s41598-018-30232-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 07/25/2018] [Indexed: 01/01/2023] Open
Abstract
Patients with chronic spinal cord injury (SCI) cannot urinate at will and must empty the bladder by self-catheterization. We tested the hypothesis that non-invasive, transcutaneous magnetic spinal cord stimulation (TMSCS) would improve bladder function in individuals with SCI. Five individuals with American Spinal Injury Association Impairment Scale A/B, chronic SCI and detrusor sphincter dyssynergia enrolled in this prospective, interventional study. After a two-week assessment to determine effective stimulation characteristics, each patient received sixteen weekly TMSCS treatments and then received “sham” weekly stimulation for six weeks while bladder function was monitored. Bladder function improved in all five subjects, but only during and after repeated weekly sessions of 1 Hz TMSCS. All subjects achieved volitional urination. The volume of urine produced voluntarily increased from 0 cc/day to 1120 cc/day (p = 0.03); self-catheterization frequency decreased from 6.6/day to 2.4/day (p = 0.04); the capacity of the bladder increased from 244 ml to 404 ml (p = 0.02); and the average quality of life ranking increased significantly (p = 0.007). Volitional bladder function was re-enabled in five individuals with SCI following intermittent, non-invasive TMSCS. We conclude that neuromodulation of spinal micturition circuitry by TMSCS may be used to ameliorate bladder function.
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27
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Ievins A, Moritz CT. Therapeutic Stimulation for Restoration of Function After Spinal Cord Injury. Physiology (Bethesda) 2018; 32:391-398. [PMID: 28814499 DOI: 10.1152/physiol.00010.2017] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 07/11/2017] [Accepted: 07/11/2017] [Indexed: 12/19/2022] Open
Abstract
Paralysis due to spinal cord injury can severely limit motor function and independence. This review summarizes different approaches to electrical stimulation of the spinal cord designed to restore motor function, with a brief discussion of their origins and the current understanding of their mechanisms of action. Spinal stimulation leads to impressive improvements in motor function along with some benefits to autonomic functions such as bladder control. Nonetheless, the precise mechanisms underlying these improvements and the optimal spinal stimulation approaches for restoration of motor function are largely unknown. Finally, spinal stimulation may augment other therapies that address the molecular and cellular environment of the injured spinal cord. The fact that several stimulation approaches are now leading to substantial and durable improvements in function following spinal cord injury provides a new perspectives on the previously "incurable" condition of paralysis.
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Affiliation(s)
- Aiva Ievins
- Department of Rehabilitation Medicine, University of Washington, Seattle, Washington.,Graduate Program in Neuroscience, University of Washington, Seattle, Washington.,Center for Sensorimotor Neural Engineering, Seattle, Washington
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28
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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: 47] [Impact Index Per Article: 7.8] [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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29
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Gad PN, Gerasimenko YP, Zdunowski S, Sayenko D, Haakana P, Turner A, Lu D, Roy RR, Edgerton VR. Iron 'ElectriRx' man: Overground stepping in an exoskeleton combined with noninvasive spinal cord stimulation after paralysis. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2015:1124-7. [PMID: 26736463 DOI: 10.1109/embc.2015.7318563] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We asked whether coordinated voluntary movement of the lower limbs could be regained in an individual having been completely paralyzed (>4 yr) and completely absent of vision (>15 yr) using a novel strategy - transcutaneous spinal cord stimulation at selected sites over the spinal vertebrae with just one week of training. We also asked whether this stimulation strategy could facilitate stepping assisted by an exoskeleton (EKSO, EKSO Bionics) that is designed so that the subject can voluntarily complement the work being performed by the exoskeleton. We found that spinal cord stimulation enhanced the level of effort that the subject could generate while stepping in the exoskeleton. In addition, stimulation improved the coordination patterns of the lower limb muscles resulting in a more continuous, smooth stepping motion in the exoskeleton. These stepping sessions in the presence of stimulation were accompanied by greater cardiac responses and sweating than could be attained without the stimulation. Based on the data from this case study it appears that there is considerable potential for positive synergistic effects after complete paralysis by combining the overground stepping in an exoskeleton, a novel transcutaneous spinal cord stimulation paradigm, and daily training.
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30
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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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31
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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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32
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Harkema SJ, Rejc E, Angeli CA. Neuromodulation of the Spinal Cord for Movement Restoration. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00098-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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33
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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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34
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Gad PN, Salyards GW, Garzel LM, Christe KL, Edgerton VR, Havton LA. Generalized convulsive seizures are associated with ketamine anesthesia in a rhesus macaque (Macaca mulatta) undergoing urodynamic studies and transcutaneous spinal cord stimulation. J Med Primatol 2017; 46:359-363. [PMID: 28727150 DOI: 10.1111/jmp.12287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2017] [Indexed: 11/30/2022]
Abstract
A female rhesus macaque developed two episodes of generalized convulsions during transcutaneous spinal cord stimulation (TSCS) and urodynamic studies under ketamine anesthesia. The seizures took place in the absence of active TSCS and bladder pressure elevation. Ketamine anesthesia remains the primary risk factor for the convulsions during these experimental procedures.
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Affiliation(s)
- Parag N Gad
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, USA
| | - Gregory W Salyards
- California National Primate Research Center, University of California, Davis, CA, USA
| | - Laura M Garzel
- California National Primate Research Center, University of California, Davis, CA, USA
| | - Kari L Christe
- California National Primate Research Center, University of California, Davis, CA, USA
| | - V Reggie Edgerton
- Departments of Integrative Biology and Physiology, Neurobiology, and Neurosurgery, University of California, Los Angeles, CA, USA
| | - Leif A Havton
- Departments of Neurology and Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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35
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Pettigrew RI, Heetderks WJ, Kelley CA, Peng GC, Member IEEE, Krosnick SH, Jakeman LB, Egan KD, Marge M. Epidural Spinal Stimulation to Improve Bladder, Bowel, and Sexual Function in Individuals With Spinal Cord Injuries: A Framework for Clinical Research. IEEE Trans Biomed Eng 2017; 64:253-262. [PMID: 28113186 PMCID: PMC5513553 DOI: 10.1109/tbme.2016.2637301] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
While some recent studies that apply epidural spinal cord stimulation (SCS) have demonstrated a breakthrough in improvement of the health and quality of the life of persons with spinal cord injury (SCI), the numbers of people who have received SCS are small. This is in sharp contrast to the thousands of persons worldwide living with SCI who have no practical recourse or hope of recovery of lost functions. Thus, the vision is to understand the full potential of this new intervention and to determine if it is safe and effective in a larger cohort, and if it is scalable so that it can be made available to all those who might benefit. To achieve this vision, the National Institute of Biomedical Imaging and Bioengineering called for and organized a consortium of multiple stakeholder groups: foundations addressing paralysis, federal and public agencies, industrial partners, academicians, and researchers, all interested in the same goal. Based on input from consortium participants, we have reasoned that a first step is to define a scalable SCS approach that is effective in restoring lost autonomic physiology, specifically bladder, bowel, and sexual function. These functions are most critical for improving the quality of life of persons living with SCI. This report outlines a framework for conducting the research needed to define such an effective SCS procedure that might seek Food and Drug Administration approval and be implemented at the population level.
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Affiliation(s)
| | - William J. Heetderks
- Formerly with the National Institute of Biomedical Imaging and Bioengineering and is now employed by the Food and Drug Administration
| | - Christine A. Kelley
- Employees of the National Institute of Biomedical Imaging and Bioengineering
| | - Grace C.Y. Peng
- Employees of the National Institute of Biomedical Imaging and Bioengineering
| | - IEEE Member
- Employees of the National Institute of Biomedical Imaging and Bioengineering
| | - Steven H. Krosnick
- Employees of the National Institute of Biomedical Imaging and Bioengineering
| | - Lyn B. Jakeman
- Employee of the National Institute of Neurological Diseases and Stroke
| | - Katharine D. Egan
- Employees of the National Institute of Biomedical Imaging and Bioengineering
| | - Michael Marge
- Employees of the National Institute of Biomedical Imaging and Bioengineering
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36
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Krucoff MO, Rahimpour S, Slutzky MW, Edgerton VR, Turner DA. Enhancing Nervous System Recovery through Neurobiologics, Neural Interface Training, and Neurorehabilitation. Front Neurosci 2016; 10:584. [PMID: 28082858 PMCID: PMC5186786 DOI: 10.3389/fnins.2016.00584] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 12/06/2016] [Indexed: 12/21/2022] Open
Abstract
After an initial period of recovery, human neurological injury has long been thought to be static. In order to improve quality of life for those suffering from stroke, spinal cord injury, or traumatic brain injury, researchers have been working to restore the nervous system and reduce neurological deficits through a number of mechanisms. For example, neurobiologists have been identifying and manipulating components of the intra- and extracellular milieu to alter the regenerative potential of neurons, neuro-engineers have been producing brain-machine and neural interfaces that circumvent lesions to restore functionality, and neurorehabilitation experts have been developing new ways to revitalize the nervous system even in chronic disease. While each of these areas holds promise, their individual paths to clinical relevance remain difficult. Nonetheless, these methods are now able to synergistically enhance recovery of native motor function to levels which were previously believed to be impossible. Furthermore, such recovery can even persist after training, and for the first time there is evidence of functional axonal regrowth and rewiring in the central nervous system of animal models. To attain this type of regeneration, rehabilitation paradigms that pair cortically-based intent with activation of affected circuits and positive neurofeedback appear to be required—a phenomenon which raises new and far reaching questions about the underlying relationship between conscious action and neural repair. For this reason, we argue that multi-modal therapy will be necessary to facilitate a truly robust recovery, and that the success of investigational microscopic techniques may depend on their integration into macroscopic frameworks that include task-based neurorehabilitation. We further identify critical components of future neural repair strategies and explore the most updated knowledge, progress, and challenges in the fields of cellular neuronal repair, neural interfacing, and neurorehabilitation, all with the goal of better understanding neurological injury and how to improve recovery.
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Affiliation(s)
- Max O Krucoff
- Department of Neurosurgery, Duke University Medical Center Durham, NC, USA
| | - Shervin Rahimpour
- Department of Neurosurgery, Duke University Medical Center Durham, NC, USA
| | - Marc W Slutzky
- Department of Physiology, Feinberg School of Medicine, Northwestern UniversityChicago, IL, USA; Department of Neurology, Feinberg School of Medicine, Northwestern UniversityChicago, IL, USA
| | - V Reggie Edgerton
- Department of Integrative Biology and Physiology, University of California, Los Angeles Los Angeles, CA, USA
| | - Dennis A Turner
- Department of Neurosurgery, Duke University Medical CenterDurham, NC, USA; Department of Neurobiology, Duke University Medical CenterDurham, NC, USA; Research and Surgery Services, Durham Veterans Affairs Medical CenterDurham, NC, USA
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37
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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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38
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Kumar S, Dey S, Jain S. Extremely low-frequency electromagnetic fields: A possible non-invasive therapeutic tool for spinal cord injury rehabilitation. Electromagn Biol Med 2016; 36:88-101. [PMID: 27399648 DOI: 10.1080/15368378.2016.1194290] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Traumatic insults to the spinal cord induce both immediate mechanical damage and subsequent tissue degeneration. The latter involves a range of events namely cellular disturbance, homeostatic imbalance, ionic and neurotransmitters derangement that ultimately result in loss of sensorimotor functions. The targets for improving function after spinal cord injury (SCI) are mainly directed toward limiting these secondary injury events. Extremely low-frequency electromagnetic field (ELF-EMF) is a possible non-invasive therapeutic intervention for SCI rehabilitation which has the potential to constrain the secondary injury-induced events. In the present review, we discuss the effects of ELF-EMF on experimental and clinical SCI as well as on biological system.
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Affiliation(s)
- Suneel Kumar
- a Department of Physiology , All India Institute of Medical Sciences , New Delhi , India.,b W. M. Keck Center for Collaborative Neuroscience, Rutgers, The State University of New Jersey , Piscataway , NJ , USA
| | - Soumil Dey
- a Department of Physiology , All India Institute of Medical Sciences , New Delhi , India
| | - Suman Jain
- a Department of Physiology , All India Institute of Medical Sciences , New Delhi , India
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39
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Neuromodulation of the neural circuits controlling the lower urinary tract. Exp Neurol 2016; 285:182-189. [PMID: 27381425 DOI: 10.1016/j.expneurol.2016.06.034] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 06/30/2016] [Accepted: 06/30/2016] [Indexed: 01/01/2023]
Abstract
The inability to control timely bladder emptying is one of the most serious challenges among the many functional deficits that occur after a spinal cord injury. We previously demonstrated that electrodes placed epidurally on the dorsum of the spinal cord can be used in animals and humans to recover postural and locomotor function after complete paralysis and can be used to enable voiding in spinal rats. In the present study, we examined the neuromodulation of lower urinary tract function associated with acute epidural spinal cord stimulation, locomotion, and peripheral nerve stimulation in adult rats. Herein we demonstrate that electrically evoked potentials in the hindlimb muscles and external urethral sphincter are modulated uniquely when the rat is stepping bipedally and not voiding, immediately pre-voiding, or when voiding. We also show that spinal cord stimulation can effectively neuromodulate the lower urinary tract via frequency-dependent stimulation patterns and that neural peripheral nerve stimulation can activate the external urethral sphincter both directly and via relays in the spinal cord. The data demonstrate that the sensorimotor networks controlling bladder and locomotion are highly integrated neurophysiologically and behaviorally and demonstrate how these two functions are modulated by sensory input from the tibial and pudental nerves. A more detailed understanding of the high level of interaction between these networks could lead to the integration of multiple neurophysiological strategies to improve bladder function. These data suggest that the development of strategies to improve bladder function should simultaneously engage these highly integrated networks in an activity-dependent manner.
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Shah PK, Sureddi S, Alam M, Zhong H, Roy RR, Edgerton VR, Gerasimenko Y. Unique Spatiotemporal Neuromodulation of the Lumbosacral Circuitry Shapes Locomotor Success after Spinal Cord Injury. J Neurotrauma 2016; 33:1709-23. [PMID: 26792233 DOI: 10.1089/neu.2015.4256] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Spinal cord epidural stimulation has resulted in the initiation of voluntary leg movements and improvement in postural, bladder, and sexual function. However, one of the limitations in reaching the full potential of epidural stimulation for therapeutic purposes in humans has been the identification of optimal stimulation configurations that can neuromodulate the spinal cord for stepping. In the present work, we investigated the mechanisms underlying the specificity of interaction between the rostral and caudal spinal cord circuitries in enabling locomotion in spinal rats (n = 10) by epidural spinal cord stimulation. By using unique spatiotemporal epidural stimulation parameters of the lumbar and sacral spinal cords, a robust stepping pattern in spinal rats was observed with only six training sessions and as early as 3 weeks post-injury. Electrophysiological evidence reveals that in addition to frequency of stimulation pulses at the stimulation sites, the relative timing between stimulation pulses applied at the lumbar (L2) and sacral (S1) segments of the spinal cord heavily impacted stepping performance. Best stepping was established at a higher stimulation frequency (40 Hz vs. 5, 10, 15, and 20Hz) and at specific relative time-intervals between the stimulation pulses (L2 pulse applied at 18-25 msec after the onset of the S1 pulse; S1 pulse applied 0-7 msec after the L2 pulse). Our data suggest that controlling pulse-to-pulse timing at multiple stimulation sources provides a novel strategy to optimize spinal stepping by fine-tuning the physiological state of the locomotor networks. These findings hold direct relevance to the clinician who will incorporate electrical stimulation strategies for optimizing control of locomotion after complete paralysis.
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Affiliation(s)
- Prithvi K Shah
- 1 Division of Rehabilitation Sciences, School of Health Technology and Management, Stony Brook University , Stony Brook, New York.,2 Department of Neurobiology, Stony Brook University , Stony Brook, New York
| | - Shakthi Sureddi
- 3 Department of Neuroscience, University of California , Los Angeles, California
| | - Monzurul Alam
- 4 Department of Neurosurgery, University of California , Los Angeles, California
| | - Hui Zhong
- 5 Department of Integrative Biology and Physiology, University of California , Los Angeles, California
| | - Roland R Roy
- 5 Department of Integrative Biology and Physiology, University of California , Los Angeles, California.,6 Brain Research Institute, University of California , Los Angeles, California
| | - V Reggie Edgerton
- 4 Department of Neurosurgery, University of California , Los Angeles, California.,5 Department of Integrative Biology and Physiology, University of California , Los Angeles, California.,6 Brain Research Institute, University of California , Los Angeles, California.,7 Department of Neurobiology, University of California , Los Angeles, California
| | - Yury Gerasimenko
- 5 Department of Integrative Biology and Physiology, University of California , Los Angeles, California.,8 Pavlov Institute of Physiology, St. Petersburg, Russia .,9 Institute of Fundamental Medicine and Biology, Kazan Federal University , Kazan, Russia
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Papastefanaki F, Matsas R. From demyelination to remyelination: the road toward therapies for spinal cord injury. Glia 2015; 63:1101-25. [PMID: 25731941 DOI: 10.1002/glia.22809] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/10/2015] [Accepted: 02/11/2015] [Indexed: 12/14/2022]
Abstract
Myelin integrity is crucial for central nervous system (CNS) physiology while its preservation and regeneration after spinal cord injury (SCI) is key to functional restoration. Disturbance of nodal organization acutely after SCI exposes the axon and triggers conduction block in the absence of overt demyelination. Oligodendrocyte (OL) loss and myelin degradation follow as a consequence of secondary damage. Here, we provide an overview of the major biological events and underlying mechanisms leading to OL death and demyelination and discuss strategies to restrain these processes. Another aspect which is critical for SCI repair is the enhancement of endogenously occurring spontaneous remyelination. Recent findings have unveiled the complex roles of innate and adaptive immune responses in remyelination and the immunoregulatory potential of the glial scar. Moreover, the intimate crosstalk between neuronal activity, oligodendrogenesis and myelination emphasizes the contribution of rehabilitation to functional recovery. With a view toward clinical applications, several therapeutic strategies have been devised to target SCI pathology, including genetic manipulation, administration of small therapeutic molecules, immunomodulation, manipulation of the glial scar and cell transplantation. The implementation of new tools such as cellular reprogramming for conversion of one somatic cell type to another or the use of nanotechnology and tissue engineering products provides additional opportunities for SCI repair. Given the complexity of the spinal cord tissue after injury, it is becoming apparent that combinatorial strategies are needed to rescue OLs and myelin at early stages after SCI and support remyelination, paving the way toward clinical translation.
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Affiliation(s)
- Florentia Papastefanaki
- Laboratory of Cellular and Molecular Neurobiology, Hellenic Pasteur Institute, Athens, 11521, Greece
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