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Spinal cord computational model

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https://www.readbyqxmd.com/read/28227989/computational-models-of-non-invasive-brain-and-spinal-cord-stimulation
#1
Pedro C Miranda, Ricardo Salvador, Cornelia Wenger, Sofia R Fernandes, Pedro C Miranda, Ricardo Salvador, Cornelia Wenger, Sofia R Fernandes, Sofia R Fernandes, Pedro C Miranda, Cornelia Wenger, Ricardo Salvador
Non-invasive brain and spinal cord stimulation techniques are increasingly used for diagnostic and therapeutic purposes. Knowledge of the spatial distribution of the induced electric field is necessary to interpret experimental results and to optimize field delivery. Since the induced electric field cannot be measured in vivo in humans, computational models play a fundamental role in determining the characteristics of the electric field. We produced computational models of the head and trunk to calculate the electric field induced in the brain and spinal cord by transcranial magnetic stimulation, transcranial direct current stimulation and transcutaneous spinal cord direct current stimulation...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227179/influence-of-electrode-configuration-on-the-electric-field-distribution-during-transcutaneous-spinal-direct-current-stimulation-of-the-cervical-spine
#2
Sofia R Fernandes, Ricardo Salvador, Cornelia Wenger, Mamede A de Carvalho, Pedro C Miranda, Sofia R Fernandes, Ricardo Salvador, Cornelia Wenger, Mamede A de Carvalho, Pedro C Miranda, Sofia R Fernandes, Pedro C Miranda, Cornelia Wenger, Ricardo Salvador, Mamede A de Carvalho
Transcutaneous spinal direct current stimulation (tsDCS) is a recent technique with promising neuromodulatory effects on spinal neuronal circuitry. The main objective of the present study was to perform a finite element analysis of the electric field distribution in tsDCS in the cervical spine region, with varying electrode configurations and geometry. A computational model of a human trunk was generated with nine tissue meshes. Three electrode configurations were tested: A) rectangular saline-soaked sponge target and return electrodes placed over C3 and T3 spinous processes, respectively; B1) circular saline-soaked sponge target and return electrodes placed over C7 spinous process and right deltoid muscle, respectively; B2) same configuration as B1, considering circular shaped electrodes with sponge and rubber layers and a small circular connector on the top surface...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226862/novel-fractal-planar-electrode-design-for-efficient-neural-stimulation
#3
Xuefeng Wei, Mehdi Benmassaoud, Miriam Meller, Sindhuja Kuchibhatla, Xuefeng Wei, Mehdi Benmassaoud, Miriam Meller, Sindhuja Kuchibhatla, Mehdi Benmassaoud, Sindhuja Kuchibhatla, Miriam Meller, Xuefeng Wei
Planar electrodes are used in epidural spinal cord stimulation and cortical stimulation. Stimulation efficiency of an electrode is characterized by its ability to activate a volume of neural tissue with lower voltage and power requirements. As current density tends to increase towards the sharp edges of an electrode, we hypothesize that electrode designs involving a greater amount of sharp edges will have higher variations of current density, and therefore increase stimulation efficiency, compared to electrodes with flat or rounded edges...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28218643/diffusion-assessment-of-cortical-changes-induced-by-traumatic-spinal-cord-injury
#4
Peng Sun, Rory K J Murphy, Paul Gamble, Ajit George, Sheng-Kwei Song, Wilson Z Ray
Promising treatments are being developed to promote functional recovery after spinal cord injury (SCI). Magnetic resonance imaging, specifically Diffusion Tensor Imaging (DTI) has been shown to non-invasively measure both axonal and myelin integrity following traumatic brain and SCI. A novel data-driven model-selection algorithm known as Diffusion Basis Spectrum Imaging (DBSI) has been proposed to more accurately delineate white matter injury. The objective of this study was to investigate whether DTI/DBSI changes that extend to level of the cerebral peduncle and internal capsule following a SCI could be correlated with clinical function...
February 17, 2017: Brain Sciences
https://www.readbyqxmd.com/read/28192461/canine-neuroanatomy-development-of-a-3d-reconstruction-and-interactive-application-for-undergraduate-veterinary-education
#5
Hazel Raffan, Julien Guevar, Matthieu Poyade, Paul M Rea
Current methods used to communicate and present the complex arrangement of vasculature related to the brain and spinal cord is limited in undergraduate veterinary neuroanatomy training. Traditionally it is taught with 2-dimensional (2D) diagrams, photographs and medical imaging scans which show a fixed viewpoint. 2D representations of 3-dimensional (3D) objects however lead to loss of spatial information, which can present problems when translating this to the patient. Computer-assisted learning packages with interactive 3D anatomical models have become established in medical training, yet equivalent resources are scarce in veterinary education...
2017: PloS One
https://www.readbyqxmd.com/read/28185477/measuring-pain-phenomena-after-spinal-cord-injury-development-and-psychometric-properties-of-the-sci-qol-pain-interference-and-pain-behavior-assessment-tools
#6
Matthew L Cohen, Pamela A Kisala, Trevor A Dyson-Hudson, David S Tulsky
OBJECTIVE: To develop modern patient-reported outcome measures that assess pain interference and pain behavior after spinal cord injury (SCI). DESIGN: Grounded-theory based qualitative item development; large-scale item calibration field-testing; confirmatory factor analyses; graded response model item response theory analyses; statistical linking techniques to transform scores to the Patient Reported Outcome Measurement Information System (PROMIS) metric. SETTING: Five SCI Model Systems centers and one Department of Veterans Affairs medical center in the United States...
February 10, 2017: Journal of Spinal Cord Medicine
https://www.readbyqxmd.com/read/28162645/-399-patient-specific-computer-models-of-spinal-cord-stimulation-for-chronic-pain-management
#7
S Lempka, J Ozinga, A Wyant, F Dong, S Jones, S Nagel, A Machado
No abstract text is available yet for this article.
April 2016: Journal of Pain: Official Journal of the American Pain Society
https://www.readbyqxmd.com/read/28155678/compression-distraction-reduction-surgical-verification-and-optimization-to-treat-the-basilar-invagination-and-atlantoaxial-dislocation-a-finite-element-analysis
#8
Xuefeng Bo, Weida Wang, Zan Chen, Zhicheng Liu
BACKGROUND: Basilar invagination (BI) combined with atlantoaxial dislocation (AAD) leads to foramen magnum stenosis and medullary spinal cord compression, causing nerve dysfunction. The purpose of the surgery is to remove the bony compression at brainstem ventral side and fix the unstable spinal segment and make it fused stably. Occipital cervical internal fixation system that simultaneously reduces atlantoaxial horizontal and vertical dislocation are established. We propose here a new compression-distraction reduction (CDR) technique...
December 28, 2016: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28152039/individualized-3d-printing-navigation-template-for-pedicle-screw-fixation-in-upper-cervical-spine
#9
Fei Guo, Jianhao Dai, Junxiang Zhang, Yichuan Ma, Guanghui Zhu, Junjie Shen, Guoqi Niu
PURPOSE: Pedicle screw fixation in the upper cervical spine is a difficult and high-risk procedure. The screw is difficult to place rapidly and accurately, and can lead to serious injury of spinal cord or vertebral artery. The aim of this study was to design an individualized 3D printing navigation template for pedicle screw fixation in the upper cervical spine. METHODS: Using CT thin slices data, we employed computer software to design the navigation template for pedicle screw fixation in the upper cervical spine (atlas and axis)...
2017: PloS One
https://www.readbyqxmd.com/read/28118155/the-effects-of-human-height-and-mass-on-the-calculated-induced-electric-fields-at-50-hz-for-comparison-with-the-emf-directive-2013-35-eu
#10
R P Findlay
A worker's height and mass can significantly affect the way in which incident low frequency electric and magnetic fields are absorbed in the body. To investigate this, several anatomically realistic human models were produced for heights between 1.56 and 1.96 m and masses between 33 and 113 kg. The human models were derived from the MAXWEL surface-based phantom, the model previously used in the EMF Directive 2013/35/EU Practical Guide to demonstrate how induced electric fields in the body are calculated. Computer simulations were carried out to calculate the low frequency EMF directive exposure limit value (ELV) quantities, i...
January 24, 2017: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
https://www.readbyqxmd.com/read/28115070/longitudinal-investigation-of-rehospitalization-patterns-in-spinal-cord-and-traumatic-brain-injury-among-medicare-beneficiaries
#11
Christopher R Pretz, James E Graham, Addie Middleton, Amol M Karmarkar, Kenneth J Ottenbacher
OBJECTIVE: To model 12-month rehospitalization risk among Medicare beneficiaries receiving inpatient rehabilitation for SCI or TBI and to create two (SCI- and TBI-specific) interactive tools enabling users to generate monthly projected probabilities for rehospitalization based on an individual patient's clinical profile at discharge from inpatient rehabilitation. DESIGN: Secondary data analysis. SETTING: More than 1,100 inpatient rehabilitation facilities across the US...
January 20, 2017: Archives of Physical Medicine and Rehabilitation
https://www.readbyqxmd.com/read/28047696/su-d-brc-05-effects-of-motion-and-variable-rbe-in-a-lung-patient-treated-with-passively-scattered-protons
#12
D Mirkovic, U Titt, P Yepes, R Mohan
PURPOSE: To evaluate effects of motion and variable relative biological effectiveness (RBE) in a lung cancer patient treated with passively scattered proton therapy using dose volume histograms associated with patient dose computed using three different methods. METHODS: A proton treatment plan of a lung cancer patient optimized using clinical treatment planning system (TPS) was used to construct a detailed Monte Carlo (MC) model of the beam delivery system and the patient specific aperture and compensator...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047535/su-f-i-38-patient-organ-specific-dose-assessment-in-coronary-ct-angiograph-using-voxellaized-volume-dose-index-in-monte-carlo-simulation
#13
Mohammadi Gh Fallal, Alam N Riyahi, Gh Graily, R Paydar
PURPOSE: Clinical use of multi detector computed tomography(MDCT) in diagnosis of diseases due to high speed in data acquisition and high spatial resolution is significantly increased. Regarding to the high radiation dose in CT and necessity of patient specific radiation risk assessment, the adoption of new method in the calculation of organ dose is completely required and necessary. In this study by introducing a conversion factor, patient organ dose in thorax region based on CT image data using MC system was calculated...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046412/we-ab-209-12-quasi-constrained-multi-criteria-optimization-for-automated-radiation-therapy-treatment-planning
#14
W T Watkins, J V Siebers
PURPOSE: To introduce quasi-constrained Multi-Criteria Optimization (qcMCO) for unsupervised radiation therapy optimization which generates alternative patient-specific plans emphasizing dosimetric tradeoffs and conformance to clinical constraints for multiple delivery techniques. METHODS: For N Organs At Risk (OARs) and M delivery techniques, qcMCO generates M(N+1) alternative treatment plans per patient. Objective weight variations for OARs and targets are used to generate alternative qcMCO plans...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28034635/patient-specific-bone-mineral-density-distribution-in-the-tibia-of-individuals-with-chronic-spinal-cord-injury-derived-from-multi-slice-peripheral-quantitative-computed-tomography-pqct-a-cross-sectional-study
#15
Sylvie Coupaud, Magnus K Gislason, Mariel Purcell, Keisuke Sasagawa, K Elizabeth Tanner
BACKGROUND: The high risk of fracture associated with chronic spinal cord injury (SCI) is attributed to extensive disuse-related bone loss in previously weight-bearing long bones. Changes in bone mineral density (BMD) after SCI have been documented extensively for the epiphyses of the tibia and femur, fracture-prone sites in this patient group. Less attention has been given to patterns of cortical bone loss in the diaphyses, but variability in BMD distributions throughout the long bones may contribute to some patients' increased susceptibility to shaft fractures in chronic SCI...
December 26, 2016: Bone
https://www.readbyqxmd.com/read/27939751/estimating-axonal-strain-and-failure-following-white-matter-stretch-using-contactin-associated-protein-as-a-fiduciary-marker
#16
Sagar Singh, Assimina A Pelegri, David I Shreiber
Axonal injury occurs during trauma when tissue-scale loads are transferred to individual axons. Computational models are used to understand this transfer and predict the circumstances that cause injury. However, these findings are limited by a lack of validating experimental work examining the mechanics of axons in their in situ state. As a first step towards validation for dynamic stretch, we use contactin-associated protein (Caspr), expressed at the nodes of Ranvier, as a fiduciary marker of quasistatic axonal stretch...
January 25, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/27843686/effect-of-spinal-cord-compression-on-local-vascular-blood-flow-and-perfusion-capacity-by-alshareef-m-krishna-v-ferdous-j-aishareef-a-kindy-m-kolachalama-vb-et-al
#17
Nancy E Epstein
BACKGROUND: Different degrees of blood flow/vascular compromise occur with anterior, posterior, or circumferential spinal cord compression/spinal cord injury (SCI). SCI is also divided into primary and secondary injury. Primary SCI refers to the original neurological damage to tissues, whereas secondary injury reflects interruption of normal blood flow leading to further inflammatory response/other local changes which contribute to additional neurological injury. METHODS: The authors developed a quantitative "3-D finite element fluid structure interaction model" of spinal cord blood flow to better document the mechanisms of secondary ischemic damage occurring in the spinal cord anteriorly, posteriorly, or circumferentially...
2016: Surgical Neurology International
https://www.readbyqxmd.com/read/27834648/epidural-stimulation-of-rat-spinal-cord-at-lumbosacral-segment-using-a-surface-electrode-a-computer-simulation-study
#18
Qi Xu, Li Kong, Hui Zhou, Jiping He
Clinical research indicates that the epidural spinal cord stimulation (ESCS) at lumbosacral segment has shown potential for promoting locomotor recovery in patients with incomplete spinal cord injury. However, the underlying neural mechanism needs to be determined by animal experiments. In order to refine experimental protocols, we used a finite element simulation to investigate the activation of nerve fibers in a rat spinal cord model. Our model is composed of a volume conductor model from L1 to S2 spinal segments and the McIntyre-Richard-Grill axon model, which is used to investigate the threshold of selected spinal fibers with different diameters at varied locations and predict the neural responses of any target fibers with bipolar electrode configuration...
November 4, 2016: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/27799905/cerebellar-and-spinal-direct-current-stimulation-in-children-computational-modeling-of-the-induced-electric-field
#19
Serena Fiocchi, Paolo Ravazzani, Alberto Priori, Marta Parazzini
Recent studies have shown that the specific application of transcranial direct current stimulation (tDCS) over the cerebellum can modulate cerebellar activity. In parallel, transcutaneous spinal DC stimulation (tsDCS) was found to be able to modulate conduction along the spinal cord and spinal cord functions. Of particular interest is the possible use of these techniques in pediatric age, since many pathologies and injuries, which affect the cerebellar cortex as well as spinal cord circuits, are diffuse in adults as well as in children...
2016: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/27760818/descending-propriospinal-neurons-mediate-restoration-of-locomotor-function-following-spinal-cord-injury
#20
Katelyn N Benthall, Ryan A Hough, Andrew D McClellan
: Following spinal cord injury (SCI) in the lamprey, there is virtually complete recovery of locomotion within a few weeks, but interestingly, axonal regeneration of reticulospinal (RS) neurons is mostly limited to short distances caudal to the injury site. To explain this situation, we hypothesize that descending propriospinal (PS) neurons relay descending drive from RS neurons to indirectly activate spinal central pattern generators (CPGs). In the present study, the contributions of PS neurons to locomotor recovery were tested in the lamprey following SCI...
January 1, 2017: Journal of Neurophysiology
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