1,720,974 research outputs found
Spinal stimulation for upper and lower extremity motor recovery after spinal cord injury
No full textThesis (Ph.D.)--University of Washington, 2024Paralysis as a result of spinal cord injury severely impairs control and movement of the extremities. Individuals living with spinal cord injury report significant difficulty with activities of daily living, which can lead to limited mobility and participation within the community. Depending upon the level of injury, restoring movement in the upper and lower extremities is a top priority. Current clinical practice uses exercise-based rehabilitation strategies to facilitate motor recovery after spinal cord injury. The overall effectiveness of exercise alone for movement restoration, however, is limited. Recently, neuromodulation of the spinal cord through electrical and optogenetic stimulation has shown promise as technologies enabling greater movement recovery. Therefore, the aims of this dissertation are to 1) review the history and use of electrical and optogenetic stimulation after spinal cord injury, 2) explore the immediate effects of transcutaneous spinal stimulation on exoskeleton-assisted walking, 3) develop a filtering technique to remove stimulation artifact in surface electromyography recordings, and 4) compare the long-term effects of epidural electrical vs. optogenetic spinal stimulation for forelimb recovery. The immediate effects of transcutaneous electrical spinal stimulation on exoskeleton-assisted walking were assessed in six participants. Stimulation enabled most participants to improve their walking performance, as evidenced by faster gait speeds, reductions in exoskeleton-assistance for stepping, and better muscle coordination. Additionally, we adapted a filtering approach to specifically remove stimulation artifacts while preserving electromyography signals in the same six participants. Lastly, we compared forelimb recovery after a cervical spinal cord injury in rats across three groups: exercise alone, epidural electrical stimulation with exercise, and optogenetic stimulation with exercise. Both stimulation approaches facilitated more recovery compared to exercise alone, with optogenetic stimulation demonstrating a nearly two-fold improvement compared to electrical stimulation. The evidence in this dissertation shows that stimulation of the spinal cord is effective for enabling greater recovery of movement and control of the extremities after spinal cord injury
Spinal Neuromodulation and Gait Training for Children with Cerebral Palsy: From Laboratory to Community
Get PDFThesis (Ph.D.)--University of Washington, 2023Abstract Spinal Neuromodulation and Gait Training for Children with Cerebral Palsy: From Laboratory to Community
Siddhi R. Shrivastav Chair of the Supervisory Committee:
Chet T. Moritz
Department of Rehabilitation Medicine, Electrical & Computer Engineering, and Physiology & Biophysics Cerebral Palsy (CP) is a movement disorder that is caused due to an injury to the developing brain around the time of birth. CP leads to abnormal posture, muscle tone and movement, that negatively affects physical function. Children with CP are less active than typically developing children. They experience participation restrictions due to impaired mobility. Currently, there are no non-invasive medical or surgical treatments that can improve children’s muscle tone along with mobility. Moreover, the effects of current physical therapy, medical and surgical interventions on children’s community walking, participation and quality of life is less known.Non-invasive neuromodulation, such as transcutaneous spinal cord stimulation (tSCS) may improve children’s muscle tone, walking function and mobility. tSCS, when combined with appropriate task-specific exercises, can harness neuroplasticity and thereby lead to long-term improvement in function. There is growing evidence of functional recovery in people with spinal cord injuries. tSCS may normalize the brain-spinal cord connectivity in CP, thereby leading to positive changes in movement and function. These functional gains may translate into children’s community walking, participation and on quality of life.
First, we review background on CP and discuss about impairments associated with CP. We then present on current medical and surgical standard of care for muscle tone management, and discuss physical therapy and rehabilitation practices to improve function in children with CP. We also summarize evidence on high-intensity treadmill training, the short burst interval treadmill training or SBLTT to improve walking function in children with CP. We discuss the potential mechanisms of tSCS in CP and summarize previous evidence of this technique for CP rehabilitation. We provide evidence on the effects of tSCS combined with SBLTT on improving muscle tone, while simultaneously improving lab-based walking function in two children with CP. We then demonstrate the long-term effects of the combination of tSCS and SBLTT on muscle tone, walking function, along with a pre- post-treatment comparison of self-reported walking and health-related outcomes. Lastly, we explore the use of StepWatch device to measure community walking performance after two interventions, SBLTT only and tSCS combined with SBLTT in children with CP. Specifically, we evaluate six variables of walking performance: (1) average strides per day, (2) percent time and (3) number of strides intensities at low, moderate, and high stride rates, (4) percentage of total strides at low, medium, and high intensities, (5) average peak stride rate, and (6) activity index
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Neuromodulation through Spinal Cord Stimulation for Functional Restoration and Rehabilitation after Cervical Spinal Cord Injury
No full textThesis (Ph.D.)--University of Washington, 2020Spinal cord injury (SCI) results in permanent neurological deficits. The limited physical function impacts quality of life and socioeconomic engagement. Up to now, we have no effective interventions to restore impaired function. Activity-dependent plasticity holds great promise to promote recovery of motor and autonomic function. Neuromodulation via electrical stimulation of the spinal cord has shown growing evidence of promoting activity-dependent plasticity and functional gains following SCI. First, we review the background information about the burden and recovery process of SCI. We also summarize current advances of pharmacological, cellular, and neuromodulation approaches. Emerging evidence with stimulation technologies demonstrates potential to facilitate neuroplasticity bridging the lesion. In the second part, we demonstrated a cost- and time-efficient experimental tool to assess forelimb function in a rodent model with severe cervical SCI. This novel strategy for the behavior task may accelerate preclinical trials. By using the behavior tasks, in the third part, we present a clinically viable brain-computer spinal interface to reanimate paralyzed forelimb function in rodents with cervical SCI. We demonstrate a stable and computationally efficient local field potential decoder enabling graded forelimb movements via epidural stimulation. Consequently, the brain-controlled epidural stimulation led to functional improvements in freely moving rats with cervical SCI. The closed-loop algorithm was implemented in an implantable size circuit capable of onboard computing, providing a clinically viable strategy to accelerate the translation of brain-computer interfaces to human use. In the fourth part, we investigate the efficacy of transcutaneous spinal stimulation paired with intensive locomotor training in two individuals with cervical SCI. We present the additive effect of transcutaneous spinal stimulation for locomotor recovery with more coordinated movements. Furthermore, we demonstrate the first evidence of transcutaneous spinal stimulation for restoring bowel function. Lastly, we discuss the potential of these neurotechnology approaches. We address the current limitations of scientific understanding and technology to guide future research to restore sensorimotor and autonomic function following cervical SCI
Methods to promote reanimation and rehabilitation of forelimb function after spinal cord injury
No full textThesis (Ph.D.)--University of Washington, 2017-08Spinal cord injury is a devastating condition that can severely limit motor and sensory function and make an individual completely dependent on others for care. The effects of spinal cord injury are debilitating, and available treatments have limited effect. Impaired signal transduction, increased inhibitory molecules near the injury site, and cell damage all contribute to poor recovery from spinal cord injury. The following chapters describe experiments that aim to address these three obstacles to restore movement to paralyzed limbs. Electrical stimulation treatment can induce movements of paralyzed limbs, but these treatments have not yet restored normal motor function. A user-controlled stimulation system may improve the effects of spinal cord stimulation by allowing the user to trigger movements relevant to a particular task. In addition, supplementary treatments that mitigate the biological reaction to spinal cord injury may be necessary to achieve lasting improvements in motor function. Chondroitinase treatment can introduce a period of plasticity in the adult central nervous system and promote sprouting of descending fibers in the injured spinal cord. Electrical stimulation may help to guide sprouting fibers toward motor neuron targets to circumvent the injury. Stem cell treatment can provide cells to replace or help rehabilitate injured cells, and electrical stimulation may help to guide these new cells toward the formation of beneficial motor circuits. This thesis demonstrates the potential of a brain-controlled spinal stimulation device to restore task-related movements, present a novel behavioral task to evaluate motor recovery in a rat model of spinal cord injury, and investigate the utility of chondroitinase and stem cell treatments in restoring function after spinal cord injury
Transcutaneous spinal cord stimulation for restoration of upper extremity function after spinal cord injury
No full textThesis (Ph.D.)--University of Washington, 2019Spinal cord injury is currently incurable. Standard of care after spinal cord injury focuses on prevention of the secondary complications and maximizing residual function. The most common site of injury is the cervical level that results in tetraplegia. Incomplete cervical injury is the most frequent neurological category. Loss of motor control and sensory function in the upper extremity is a particularly devastating aspect of cervical injuries that impairs the ability to perform activities of daily living. Restoration of hand and arm function is consistently rated as the highest treatment priority among people with tetraplegia due to cervical spinal cord injury, 5-fold higher than any other function included in the surveys. Nevertheless, current approaches to improve hand and arm function are largely ineffective. Electrical spinal cord stimulation, however, is one of the emerging neuromodulation strategies to restore motor function. The aims of this dissertation are to (1) review the applications of therapeutic electrical spinal cord stimulation after spinal cord injury, (2) determine improvements in hand and arm function resulting from non-invasive electrical cervical spinal cord stimulation, and (3) quantify long-term benefits that may persist beyond the stimulation. Therapeutic potential of transcutaneous spinal cord stimulation is evaluated in a prospective, open-label, two arm cross-over study. Intervention arms consist of intensive upper limb functional task training alone and transcutaneous electrical cervical spinal cord stimulation combined with training. The Graded Redefined Assessment of Strength, Sensation and Prehension is used as the primary outcome measure. Improvements achieved by training alone are compared to those obtained when transcutaneous spinal cord stimulation is paired with training. The findings demonstrate that transcutaneous cervical spinal cord stimulation has augmentative effect on restoration of hand and arm function. Additionally, gains are maintained up to six months without stimulation or training, suggesting that electrical stimulation can promote neuroplasticity. This dissertation provides evidence that transcutaneous spinal cord stimulation is a highly promising intervention for recovery of upper extremity function after cervical spinal cord injury, with the significant advantage of not requiring surgery
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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