35 results on '"Christopher J. Stanley"'
Search Results
2. Detecting SARS-CoV-2 at point of care: preliminary data comparing loop-mediated isothermal amplification (LAMP) to polymerase chain reaction (PCR)
- Author
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Marc F. Österdahl, Karla A. Lee, Mary Ni Lochlainn, Stuart Wilson, Sam Douthwaite, Rachel Horsfall, Alyce Sheedy, Simon D. Goldenberg, Christopher J. Stanley, Tim D. Spector, and Claire J. Steves
- Subjects
Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background A cost effective and efficient diagnostic tool for COVID-19 as near to the point of care (PoC) as possible would be a game changer in the current pandemic. We tested reverse transcription loop mediated isothermal amplification (RT-LAMP), a method which can produce results in under 30 min, alongside standard methods in a real-life clinical setting. Methods This prospective service improvement project piloted an RT-LAMP method on nasal and pharyngeal swabs on 21 residents of a high dependency care home, with two index COVID-19 cases, and compared it to multiplex tandem reverse transcription polymerase chain reaction (RT-PCR). We recorded vital signs of patients to correlate clinical and laboratory information and calculated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of a single swab using RT-LAMP compared with the current standard, RT-PCR, as per Standards for Reporting Diagnostic Accuracy Studies (STARD) guidelines. Results The novel method accurately detected 8/10 RT-PCR positive cases and identified a further 3 positive cases. Eight further cases were negative using both methods. Using repeated RT-PCR as a “gold standard”, the sensitivity and specificity of a single novel test were 80 and 73% respectively. PPV was 73% and NPV was 83%. Incorporating retesting of low signal RT-LAMP positives improved the specificity to 100%. We also speculate that hypothermia may be a significant early clinical sign of COVID-19. Conclusions RT-LAMP testing for SARS-CoV-2 was found to be promising, fast and to work equivalently to RT-PCR methods. RT-LAMP has the potential to transform COVID-19 detection, bringing rapid and accurate testing to the PoC. RT-LAMP could be deployed in mobile community testing units, care homes and hospitals to detect disease early and prevent spread.
- Published
- 2020
- Full Text
- View/download PDF
3. Toward a hybrid exoskeleton for crouch gait in children with cerebral palsy: neuromuscular electrical stimulation for improved knee extension
- Author
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Blynn L. Shideler, Thomas C. Bulea, Ji Chen, Christopher J. Stanley, Andrew J. Gravunder, and Diane L. Damiano
- Subjects
Functional electrical stimulation (FES) ,Exoskeleton ,Crouch gait ,Graphical user interface (GUI) ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Abstract Background Neuromuscular Electrical Stimulation (NMES) has been utilized for many years in cerebral palsy (CP) with limited success despite its inherent potential for improving muscle size and/or strength, inhibiting or reducing spasticity, and enhancing motor performance during functional activities such as gait. While surface NMES has been shown to successfully improve foot drop in CP and stroke, correction of more complex gait abnormalities in CP such as flexed knee (crouch) gait remains challenging due to the level of stimulation needed for the quadriceps muscles that must be balanced with patient tolerability and the ability to deliver NMES assistance at precise times within a gait cycle. Methods This paper outlines the design and evaluation of a custom, noninvasive NMES system that can trigger and adjust electrical stimulation in real-time. Further, this study demonstrates feasibility of one possible application for this digitally-controlled NMES system as a component of a pediatric robotic exoskeleton to provide on-demand stimulation to leg muscles within specific phases of the gait cycle for those with CP and other neurological disorders who still have lower limb sensation and volitional control. A graphical user interface was developed to digitally set stimulation parameters (amplitude, pulse width, and frequency), timing, and intensity during walking. Benchtop testing characterized system delay and power output. System performance was investigated during a single session that consisted of four overground walking conditions in a 15-year-old male with bilateral spastic CP, GMFCS Level III: (1) his current Ankle-Foot Orthosis (AFO); (2) unassisted Exoskeleton; (3) NMES of the vastus lateralis; and (4) NMES of the vastus lateralis and rectus femoris. We hypothesized in this participant with crouch gait that NMES triggered with low latency to knee extensor muscles during stance would have a modest but positive effect on knee extension during stance. Results The system delivers four channels of NMES with average delays of 16.5 ± 13.5 ms. Walking results show NMES to the vastus lateralis and rectus femoris during stance immediately improved mean peak knee extension during mid-stance (p = 0.003*) and total knee excursion (p = 0.009*) in the more affected leg. The electrical design, microcontroller software and graphical user interface developed here are included as open source material to facilitate additional research into digitally-controlled surface stimulation ( github.com/NIHFAB/NMES ). Conclusions The custom, digitally-controlled NMES system can reliably trigger electrical stimulation with low latency. Precisely timed delivery of electrical stimulation to the quadriceps is a promising treatment for crouch. Our ultimate goal is to synchronize NMES with robotic knee extension assistance to create a hybrid NMES-exoskeleton device for gait rehabilitation in children with flexed knee gait from CP as well as from other pediatric disorders. Trial registration clinicaltrials.gov, ID: NCT01961557 . Registered 11 October 2013; Last Updated 27 January 2020.
- Published
- 2020
- Full Text
- View/download PDF
4. Polytypism and Polysomatism in Mixed-Layer Chalcogenides: Characterization of PbBi4Te4S3 and Inferences for Ordered Phases in the Aleksite Series
- Author
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Nigel J. Cook, Cristiana L. Ciobanu, Wenyuan Liu, Ashley Slattery, Benjamin P. Wade, Stuart J. Mills, and Christopher J. Stanley
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bismuth chalcogenides ,aleksite series ,high-angle annular dark-field scanning transmission electron microscopy ,Mineralogy ,QE351-399.2 - Abstract
Bi-Pb-chalcogenides of the aleksite series represent homologous mixed-layer compounds derived from tetradymite (Bi2Te2S). Considering tetradymite as composed of five-atom (Bi2Te2S) layers, the named minerals of the aleksite homologous series, aleksite (PbBi2Te2S2) and saddlebackite, (Pb2Bi2Te2S3) have been considered as phases formed by regular stacking of longer seven- and nine-atom layers. High-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) imaging of thinned foils prepared in-situ on domains deemed homogeneous from electron probe microanalysis, STEM energy-dispersive X-ray spectrometry (EDS) element mapping and fast Fourier transforms (FFTs) from the images offer new insights into these structures. The hitherto-unnamed phase, PbBi4Te4S3, previously interpreted as regular intergrowths of five- and seven-atom layers, is characterized in terms of regular repeats of five- and seven-atom layers over distances of at least 350 nm, defining the (57), or 24H polytype. Imaging of other domains in the same lamella with identical composition at the electron microprobe scale reveals the presence of two additional polytypes: (5559), or 48H; and (557.559) or 72H. Unit cell dimensions for all three polytypes of PbBi4Te4S3 can be both measured and predicted from the HAADF STEM imaging and FFTs. STEM EDS mapping of each polytype confirm the internal structure of each layer. Lead and S occur within the centre of the layers, i.e., Te−Bi−S−Pb−S−Bi−Te in the seven-atom layer, Te−Bi−S−Pb−S−Pb−S−Bi−Te in the nine-atom layer, and so on. Polytypism is an intrinsic feature of the aleksite series, with each named mineral or unnamed phase, except the simple five-atom layer, defined by several alternative stacking sequences of different length, readily explaining the differing c values given in previous work. Homology is defined in terms of layer width and the stacking arrangement of those layers. Coherent structures of the same composition need not only be built of layers of adjacent size (i.e., five- and seven-atom layers) but, as exemplified by the (5559) polytype, may also contain non-adjacent layers, a finding not anticipated in previous work. New polysomes remain to be discovered in nature and each potentially exists as multiple polytypes. The present study further emphasizes the utility of HAADF STEM imaging and atomic-scale STEM EDS element mapping as an optimal tool for tracking stacking sequences and characterising structures in mixed-layer compounds.
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- 2019
- Full Text
- View/download PDF
5. The first occurrence of the carbide anion, C4–, in an oxide mineral: Mikecoxite, ideally (CHg4)OCl2, from the McDermitt open-pit mine, Humboldt County, Nevada, U.S.A
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Mark A. Cooper, Gail Dunning, Frank C. Hawthorne, Chi Ma, Anthony R. Kampf, John Spratt, Christopher J. Stanley, and Andrew G. Christy
- Subjects
Geophysics ,Geochemistry and Petrology - Abstract
Mikecoxite, ideally (CHg4)OCl2, is the first mercury-oxide-chloride-carbide containing a C4– anion coordinated by four Hg atoms (a permercurated methane derivative) to be described as a mineral species. It was found at the McDermitt open-pit mine on the eastern margin of the McDermitt Caldera, Humboldt County, Nevada, U.S.A. It is monoclinic, space group P21/n, Z = 4; a = 10.164(5), b = 10.490(4), c = 6.547(3) Å, V 698.0(5) Å3. Chemical analysis by electron microprobe gave Hg 86.38, Cl 11.58, Br 0.46, C 1.81, sum = 100.23 wt%, and O was detected but the signal was too weak for quantitative chemical analysis. The empirical formula, calculated on the basis of Hg + Cl + Br = 6 apfu, is (C1.19Hg3.39)(Cl2.57Br0.05)Σ2.62, and the ideal formula based on the chemical analysis and the crystal structure is (CHg4)OCl2. The seven strongest lines in the X-ray powder diffraction pattern are [d (Å), I, (hkl)]: 2.884, 100, (230); 2.989, 81, (301, 301, 112, 112, 131, 131); 2.673, 79, (122, 122, 212, 212); 1.7443, 40, (060, 432, 432); 5.49, 34, (101, 101); 4.65, 32, (120); 2.300, 30, (312, 312). The Raman spectrum shows three bands at 638, 675, and 704 cm–1, well above the range characteristic of NHg4 stretching vibrations between 540 and 580 cm–1, that are assigned to CHg4 stretching vibrations. Mikecoxite forms intergrowths of bladed crystals up to 100 μm long that occur on granular quartz or in vugs associated with kleinite. It is black with a submetallic to metallic luster and strong specular reflections and does not fluoresce under short-or long-wave ultraviolet light. Neither cleavage nor parting were observed, and the calculated density is 8.58 g/cm3. In the crystal structure of mikecoxite, (C4–Hg42+) groups link through O2– ions to form three-membered rings that polymerize into corrugated [CHg4OCl]+ layers with near-linear C4––Hg2+–O and C 4––Hg2+–Cl linkages. The layers link in the third direction directly via weak Hg2+–O2– and Hg2+–Cl– bonds to adjacent layers and also indirectly via interlayer Cl–. A bond-valence parameter has been derived for (Hg2+–C4–) bonds: Ro = 2.073 Å, b = 0.37, which gives bond-valence sums at the C4– ions in accord with the valence-sum rule. The source of carbon for mikecoxite in the volcanic high-desert environment of the type locality seems to be methane, with the reaction catalyzed by microbiota through full mercuration of carbon atoms, beyond the first stage that produces the volatile and highly mobile methylmercury, [CH3Hg]+, a potent neurotoxin that accumulates in marine food chains. Both the mineral and the mineral name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA 2021-060). The mineral is named after Michael F. Cox (b. 1958), a founding member of the New Almaden Quicksilver County Park Association (NAQCPA) who was responsible for characterizing and remediating environmental mercury on-site and who recovered the rock containing the new mineral.
- Published
- 2023
6. Pyradoketosite, a new, unexpected, polymorph of Ag3SbS3 from the Monte Arsiccio mine (Apuan Alps, Tuscany, Italy)
- Author
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Cristian Biagioni, Luca Bindi, Yves Moëlo, Christopher J. Stanley, and Federica Zaccarini
- Subjects
Geophysics ,Geochemistry and Petrology - Abstract
Although everything seemed clear about the Ag-Sb-S compounds belonging to one of the more deeply studied experimental systems, nature allowed us to discover a new polymorph of Ag3SbS3, which could represent a compound for assessing new technological potentialities. The new mineral species pyradoketosite, Ag3SbS3 (IMA 2019-132), was discovered in the pyrite + baryte + iron oxide ore deposit of the Monte Arsiccio mine, Apuan Alps, Tuscany, Italy. It occurs as brittle orange acicular crystals, up to 200 μm in length and 25 μm in thickness, with adamantine luster. Under reflected light, pyradoketosite is slightly bluish-gray, with abundant orange internal reflections. Bireflectance is weak, and anisotropism was not observed, being masked by abundant internal reflections. Minimum and maximum reflectance data for the wavelengths recommended by the Commission on Ore Mineralogy [Rmin/Rmax (%) (λ, nm)] are 32.8/32.9 (470), 30.2/30.7 (546), 29.0/29.6 (589), and 27.5/28.4 (650). Electron microprobe analysis gave (mean of 6 spot analyses, in wt%): Ag 59.81, Sb 22.63, S 17.78, total 100.22. On the basis of (Ag+Sb) = 4 atoms per formula unit, the empirical formula of pyradoketosite is Ag2.996(11)Sb1.004(11)S2.996(15). Pyradoketosite is monoclinic, space group P21/n, with a = 13.7510(15), b = 6.9350(6), c = 19.555(2) Å, β = 94.807(4)°, V = 1858.3(3) Å3, Z = 12. The crystal structure was solved and refined to R1 = 0.063 on the basis of 2682 unique reflections with Fo > 4σ(Fo) and 191 refined parameters. The structure of pyradoketosite can be described as formed by the alternation of {101} layers: an Sb-rich layer, Sb3AgS3, and two distinct Ag8S6 layers. This layered organization allows identifying structural relationships with the wittichenite-skinnerite pair. Pyradoketosite is associated with pyrargyrite, tetrahedrite-(Hg), valentinite, and probable pyrostilpnite in baryte + dolomite + quartz veins embedded in metadolostone. Its name derives from the old Greek words “πυρ” (fire) and “άδόκητος” (unforeseen), because of the unexpected occurrence of this third polymorph of the compound Ag3SbS3.
- Published
- 2022
7. Training high level balance and stepping responses in atypical progressive supranuclear palsy: a case report
- Author
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Earllaine Croarkin, Krystle Robinson, Christopher J. Stanley, and Cris Zampieri
- Subjects
Physical Therapy, Sports Therapy and Rehabilitation - Abstract
Progressive supranuclear palsy (PSP) is a neurodegenerative condition, typically presenting with, but not limited to, impairments of postural instability, gait, and gaze stability.This case report describes the multifactorial assessment and rehabilitation of a patient with atypical PSP who has significant gaze deficits, asymmetrical stepping responses, trunk rigidity, and reduced posterior excursion on limits of stability.Evaluation utilized computerized gait and balance assessments, foot clearance analysis, a squat test, and a timed stepping test. The intervention included boxing, stepping tasks, and treadmill training each with eye movement challenges. A total of 15 hours of physical therapy was provided; 1 hour, 2 times a week.Post-intervention improvements were noted subjectively, on eye-body coordination, and objectively, on limits of stability, foot clearance, and task performance (squats, timed stepping). Follow-up demonstrated some decline from posttest results; however, patient-reported adherence to the program was less than recommended.A multifactorial rehabilitation program can improve balance, eye-body coordination, and strength in a high functioning patient with atypical PSP. Longitudinal randomized controlled studies are suggested to further investigate this interventional approach in high functioning individuals diagnosed with atypical PSP.
- Published
- 2023
8. User-driven control increases cortical activity during treadmill walking: An EEG study.
- Author
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Thomas C. Bulea, Jonghyun Kim 0001, Diane L. Damiano, Christopher J. Stanley, and Hyung-Soon Park
- Published
- 2014
- Full Text
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9. Low-cost implementation of a self-paced treadmill by using a commercial depth sensor.
- Author
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Jonghyun Kim 0001, Andrew Gravunder, Christopher J. Stanley, and Hyung-Soon Park
- Published
- 2013
- Full Text
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10. A user-driven treadmill control scheme for simulating overground locomotion.
- Author
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Jonghyun Kim 0001, Christopher J. Stanley, Lindsey A. Curatalo, and Hyung-Soon Park
- Published
- 2012
- Full Text
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11. A Practical Strategy for sEMG-Based Knee Joint Moment Estimation During Gait and Its Validation in Individuals With Cerebral Palsy.
- Author
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Suncheol Kwon, Hyung-Soon Park, Christopher J. Stanley, Jung Kim, Jonghyun Kim 0001, and Diane L. Damiano
- Published
- 2012
- Full Text
- View/download PDF
12. Toward a hybrid exoskeleton for crouch gait in children with cerebral palsy: neuromuscular electrical stimulation for improved knee extension
- Author
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Thomas C. Bulea, Blynn L. Shideler, Ji Chen, Andrew J. Gravunder, Diane L. Damiano, and Christopher J. Stanley
- Subjects
Male ,030506 rehabilitation ,medicine.medical_specialty ,Foot drop ,Functional electrical stimulation (FES) ,Adolescent ,Knee Joint ,medicine.medical_treatment ,Powered exoskeleton ,Electric Stimulation Therapy ,Health Informatics ,Prosthesis Design ,Cerebral palsy ,lcsh:RC321-571 ,Graphical user interface (GUI) ,03 medical and health sciences ,Physical medicine and rehabilitation ,Gait (human) ,Spastic ,Humans ,Medicine ,Spasticity ,lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry ,Gait Disorders, Neurologic ,Rehabilitation ,business.industry ,Cerebral Palsy ,Research ,Exoskeleton Device ,medicine.disease ,Crouch gait ,Exoskeleton ,Muscle Spasticity ,medicine.symptom ,0305 other medical science ,business ,human activities - Abstract
Background Neuromuscular Electrical Stimulation (NMES) has been utilized for many years in cerebral palsy (CP) with limited success despite its inherent potential for improving muscle size and/or strength, inhibiting or reducing spasticity, and enhancing motor performance during functional activities such as gait. While surface NMES has been shown to successfully improve foot drop in CP and stroke, correction of more complex gait abnormalities in CP such as flexed knee (crouch) gait remains challenging due to the level of stimulation needed for the quadriceps muscles that must be balanced with patient tolerability and the ability to deliver NMES assistance at precise times within a gait cycle. Methods This paper outlines the design and evaluation of a custom, noninvasive NMES system that can trigger and adjust electrical stimulation in real-time. Further, this study demonstrates feasibility of one possible application for this digitally-controlled NMES system as a component of a pediatric robotic exoskeleton to provide on-demand stimulation to leg muscles within specific phases of the gait cycle for those with CP and other neurological disorders who still have lower limb sensation and volitional control. A graphical user interface was developed to digitally set stimulation parameters (amplitude, pulse width, and frequency), timing, and intensity during walking. Benchtop testing characterized system delay and power output. System performance was investigated during a single session that consisted of four overground walking conditions in a 15-year-old male with bilateral spastic CP, GMFCS Level III: (1) his current Ankle-Foot Orthosis (AFO); (2) unassisted Exoskeleton; (3) NMES of the vastus lateralis; and (4) NMES of the vastus lateralis and rectus femoris. We hypothesized in this participant with crouch gait that NMES triggered with low latency to knee extensor muscles during stance would have a modest but positive effect on knee extension during stance. Results The system delivers four channels of NMES with average delays of 16.5 ± 13.5 ms. Walking results show NMES to the vastus lateralis and rectus femoris during stance immediately improved mean peak knee extension during mid-stance (p = 0.003*) and total knee excursion (p = 0.009*) in the more affected leg. The electrical design, microcontroller software and graphical user interface developed here are included as open source material to facilitate additional research into digitally-controlled surface stimulation (github.com/NIHFAB/NMES). Conclusions The custom, digitally-controlled NMES system can reliably trigger electrical stimulation with low latency. Precisely timed delivery of electrical stimulation to the quadriceps is a promising treatment for crouch. Our ultimate goal is to synchronize NMES with robotic knee extension assistance to create a hybrid NMES-exoskeleton device for gait rehabilitation in children with flexed knee gait from CP as well as from other pediatric disorders. Trial registration clinicaltrials.gov, ID: NCT01961557. Registered 11 October 2013; Last Updated 27 January 2020.
- Published
- 2020
13. Implementing overground turning on a linear treadmill.
- Author
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Hyung-Soon Park, Sang Hoon Chae, Jungwon Yoon, Jonghyun Kim 0001, Amanda Sudduth, and Christopher J. Stanley
- Published
- 2015
- Full Text
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14. Detecting SARS-CoV-2 at point of care: preliminary data comparing loop-mediated isothermal amplification (LAMP) to polymerase chain reaction (PCR)
- Author
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Stuart Mark Wilson, Sam Douthwaite, Rachel Horsfall, Alyce Sheedy, Simon D. Goldenberg, Mary Ni Lochlainn, Karla A. Lee, Marc F. Osterdahl, Claire J. Steves, Tim D. Spector, and Christopher J. Stanley
- Subjects
Male ,0301 basic medicine ,medicine.medical_specialty ,Point-of-Care Systems ,Pneumonia, Viral ,Vital signs ,Loop-mediated isothermal amplification ,Polymerase Chain Reaction ,Sensitivity and Specificity ,lcsh:Infectious and parasitic diseases ,law.invention ,Betacoronavirus ,03 medical and health sciences ,COVID-19 Testing ,0302 clinical medicine ,law ,Internal medicine ,medicine ,Humans ,lcsh:RC109-216 ,Multiplex ,Prospective Studies ,030212 general & internal medicine ,Pandemics ,Reverse Transcription Loop-mediated Isothermal Amplification ,Polymerase chain reaction ,Aged ,Point of care ,Aged, 80 and over ,Clinical Laboratory Techniques ,SARS-CoV-2 ,business.industry ,COVID-19 ,Gold standard (test) ,Middle Aged ,Data Accuracy ,Reverse transcription polymerase chain reaction ,030104 developmental biology ,Infectious Diseases ,Molecular Diagnostic Techniques ,Female ,Coronavirus Infections ,business ,Nucleic Acid Amplification Techniques ,Preliminary Data ,Research Article - Abstract
Background A cost effective and efficient diagnostic tool for COVID-19 as near to the point of care (PoC) as possible would be a game changer in the current pandemic. We tested reverse transcription loop mediated isothermal amplification (RT-LAMP), a method which can produce results in under 30 min, alongside standard methods in a real-life clinical setting. Methods This prospective service improvement project piloted an RT-LAMP method on nasal and pharyngeal swabs on 21 residents of a high dependency care home, with two index COVID-19 cases, and compared it to multiplex tandem reverse transcription polymerase chain reaction (RT-PCR). We recorded vital signs of patients to correlate clinical and laboratory information and calculated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of a single swab using RT-LAMP compared with the current standard, RT-PCR, as per Standards for Reporting Diagnostic Accuracy Studies (STARD) guidelines. Results The novel method accurately detected 8/10 RT-PCR positive cases and identified a further 3 positive cases. Eight further cases were negative using both methods. Using repeated RT-PCR as a “gold standard”, the sensitivity and specificity of a single novel test were 80 and 73% respectively. PPV was 73% and NPV was 83%. Incorporating retesting of low signal RT-LAMP positives improved the specificity to 100%. We also speculate that hypothermia may be a significant early clinical sign of COVID-19. Conclusions RT-LAMP testing for SARS-CoV-2 was found to be promising, fast and to work equivalently to RT-PCR methods. RT-LAMP has the potential to transform COVID-19 detection, bringing rapid and accurate testing to the PoC. RT-LAMP could be deployed in mobile community testing units, care homes and hospitals to detect disease early and prevent spread.
- Published
- 2020
15. Algorithmic localization of high-density EEG electrode positions using motion capture
- Author
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Christopher J. Stanley, Diane L. Damiano, Thomas C. Bulea, and Lauren N. Hirth
- Subjects
0301 basic medicine ,Computer science ,Electroencephalography ,Motion capture ,Article ,03 medical and health sciences ,0302 clinical medicine ,Position (vector) ,medicine ,Humans ,Computer vision ,Child ,Electrodes ,Brain Mapping ,medicine.diagnostic_test ,business.industry ,General Neuroscience ,Frame (networking) ,Process (computing) ,Brain ,Magnetic Resonance Imaging ,030104 developmental biology ,Child, Preschool ,Artificial intelligence ,Stylus ,Spline interpolation ,business ,030217 neurology & neurosurgery ,Interpolation - Abstract
Background Accurate source localization from electroencephalography (EEG) requires electrode co-registration to brain anatomy, a process that depends on precise measurement of 3D scalp locations. Stylus digitizers and camera-based scanners for such measurements require the subject to remain still and therefore are not ideal for young children or those with movement disorders. New method Motion capture accurately measures electrode position in one frame but marker placement adds significant setup time, particularly in high-density EEG. We developed an algorithm, named MoLo and implemented as an open-source MATLAB toolbox, to compute 3D electrode coordinates from a subset of positions measured in motion capture using spline interpolation. Algorithm accuracy was evaluated across 5 different-sized head models. Results MoLo interpolation reduced setup time by approximately 10 min for 64-channel EEG. Mean electrode interpolation error was 2.95 ± 1.3 mm (range: 0.38–7.98 mm). Source localization errors with interpolated compared to true electrode locations were below 1 mm and 0.1 mm in 75 % and 35 % of dipoles, respectively. Comparison with existing methods MoLo location accuracy is comparable to stylus digitizers and camera-scanners, common in clinical research. The MoLo algorithm could be deployed with other tools beyond motion capture, e.g., a stylus, to extract high-density EEG electrode locations from a subset of measured positions. The algorithm is particularly useful for research involving young children and others who cannot remain still for extended time periods. Conclusions Electrode position and source localization errors with MoLo are similar to other modalities supporting its use to measure high-density EEG electrode positions in research and clinical settings.
- Published
- 2020
16. Detecting SARS-CoV-2 at point of care: Preliminary data comparing Loop-mediated isothermal amplification (LAMP) to PCR
- Author
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Scott Wilson, Karla A. Lee, Rachel Horsfall, Alyce Sheedy, Christopher J. Stanley, Marc F. Osterdahl, Simon D. Goldenberg, Claire J. Steves, Tim D. Spector, Sam Douthwaite, and Ni Lochlainn M
- Subjects
Reverse transcription polymerase chain reaction ,medicine.medical_specialty ,business.industry ,Positive predicative value ,Internal medicine ,medicine ,Vital signs ,Loop-mediated isothermal amplification ,Multiplex ,Gold standard (test) ,business ,Reverse Transcription Loop-mediated Isothermal Amplification ,Point of care - Abstract
BackgroundThe need for a fast and reliable test for COVID-19 is paramount in managing the current pandemic. A cost effective and efficient diagnostic tool as near to the point of care (PoC) as possible would be a game changer in current testing. We tested reverse transcription loop mediated isothermal amplification (RT-LAMP), a method which can produce results in under 30 minutes, alongside standard methods in a real-life clinical setting.MethodsThis service improvement project piloted a research RT-LAMP method on nasal and pharyngeal swabs on 21 residents in a high dependency care home, with two index COVID-19 cases, and compared it to multiplex tandem reverse transcription polymerase chain reaction (RT-PCR). We calculated the sensitivity, specificity, positive and negative predictive values of a single RT-LAMP swab compared to RT-PCR, as per STARD guidelines. We also recorded vital signs of patients to correlate clinical and laboratory information.FindingsThe novel method accurately detected 8/10 PCR positive cases and identified a further 3 positive cases. Eight further cases were negative using both methods. Using repeated RT-PCR as a “gold standard”, the sensitivity and specificity of the novel test were 80% and 73% respectively. Positive predictive value (PPV) was 73% and negative predictive value (NPV) was 83%. We also observed hypothermia to be a significant early clinical sign in a number of COVID-19 patients in this setting.InterpretationRT-LAMP testing for SARS-CoV-2 was found to be promising, fast, easy to use and to work equivalently to RT-PCR methods. Definitive studies to evaluate this method in larger cohorts are underway. RT-LAMP has the potential to transform COVID-19 detection, bringing rapid and accurate testing to the point of care. This method could be deployed in mobile testing units in the community, care homes and hospitals to detect disease early and prevent spread.
- Published
- 2020
17. Inter-joint coordination analysis of reach-to-grasp kinematics in children and adolescents with obstetrical brachial plexus palsy
- Author
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Sahana N. Kukke, Sylvain Brochard, Christopher J. Stanley, Diane L. Damiano, Christian Mayfield, and Katharine E. Alter
- Subjects
Male ,Wrist Joint ,Shoulder ,medicine.medical_specialty ,Adolescent ,Biophysics ,Kinematics ,Wrist ,Article ,03 medical and health sciences ,0302 clinical medicine ,Birth Injuries ,medicine ,Humans ,Orthopedics and Sports Medicine ,Reach to grasp ,Brachial Plexus Neuropathies ,Child ,Joint (geology) ,030222 orthopedics ,Palsy ,Hand Strength ,Shoulder Joint ,business.industry ,medicine.disease ,Birth injury ,Biomechanical Phenomena ,medicine.anatomical_structure ,Child, Preschool ,Physical therapy ,Upper limb ,Female ,business ,Brachial plexus ,030217 neurology & neurosurgery - Abstract
Background Obstetrical brachial plexus palsy is a common birth injury to nerves passing through the brachial plexus that may result in structural and functional abnormalities. Individual joint trajectories from kinematic analyses have been used to evaluate the source and extent of abnormalities. Here, two summary measures of limb kinematics were utilized: 1) the Arm Profile Score summarizing upper limb joint kinematic abnormalities from a typical pattern across a task, and 2) the recently developed Multi-joint Coordination Measure using principal component analysis to characterize typical coordination of multiple joints throughout a task and compute deviations in time and space. Our aim was to compare these kinematic measures in persons with and without injury and relate these to clinical and functional scales. Methods 3D kinematic data from 10 upper limb joints were collected on 15 children and adolescents with obstetrical brachial plexus palsy and 21 controls during a reach-to-grasp task in both limbs. The two kinematic measures were computed and correlated with each other and the Mallet and ABILIHAND-Kids. Findings Both measures revealed that joint angles primarily contributing to shoulder and wrist motion were most prominently affected in the non-dominant limb in obstetrical brachial plexus palsy, with the Multi-joint Coordination Measure additionally indicating when in the motion coordination worsens. These were moderately interrelated but neither correlated with other scales. Interpretation The Multi-joint Coordination Measure, while related to the Arm Profile Score, may have additional utility for individualized treatment planning and evaluation of any motor task due to the unique spatial-temporal information provided.
- Published
- 2017
18. Task-Specific and Functional Effects of Speed-Focused Elliptical or Motor-Assisted Cycle Training in Children With Bilateral Cerebral Palsy: Randomized Clinical Trial
- Author
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Katharine E. Alter, Laurie B. Ohlrich, Christopher J. Stanley, and Diane L. Damiano
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Male ,030506 rehabilitation ,medicine.medical_specialty ,Adolescent ,Article ,law.invention ,Cerebral palsy ,Task (project management) ,03 medical and health sciences ,0302 clinical medicine ,Gait (human) ,Physical medicine and rehabilitation ,Randomized controlled trial ,law ,Medicine ,Humans ,Muscle Strength ,Child ,Muscle, Skeletal ,Gait ,Bilateral cerebral palsy ,business.industry ,Cerebral Palsy ,General Medicine ,medicine.disease ,Bicycling ,Exercise Therapy ,Locomotor training ,Treatment Outcome ,Lower Extremity ,Motor Skills ,Child, Preschool ,Physical therapy ,Female ,0305 other medical science ,business ,030217 neurology & neurosurgery - Abstract
Background. Locomotor training using treadmills or robotic devices is commonly utilized to improve gait in cerebral palsy (CP); however, effects are inconsistent and fail to exceed those of equally intense alternatives. Possible limitations of existing devices include fixed nonvariable rhythm and too much limb or body weight assistance. Objective: To quantify and compare effectiveness of a motor-assisted cycle and a novel alternative, an elliptical, in CP to improve interlimb reciprocal coordination through intensive speed-focused leg training. Methods: A total of 27 children with bilateral CP, 5 to 17 years old, were randomized to 12 weeks of 20 minutes, 5 days per week home-based training (elliptical = 14; cycle = 13) at a minimum of 40 revolutions per minute, with resistance added when speed target was achieved. Primary outcomes were self-selected and fastest voluntary cadence on the devices and gait speed. Secondary outcomes included knee muscle strength, and selective control and functional mobility measures. Results: Cadence on trained but not nontrained devices increased, demonstrating task specificity of training and increased exercise capability. Mean gait speed did not increase in either group, nor did parent-reported functional mobility. Knee extensor strength increased in both. An interaction between group and time was seen in selective control with scores slightly increasing for the elliptical and decreasing for the cycle, possibly related to tighter limb coupling with cycling. Conclusions: Task-specific effects were similarly positive across groups, but no transfer was seen to gait or function. Training dose was low (≤20 hours) compared with intensive upper-limb training recommendations and may be insufficient to produce appreciable clinical change.
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- 2017
19. Part 2: Adaptation of Gait Kinematics in Unilateral Cerebral Palsy Demonstrates Preserved Independent Neural Control of Each Limb
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Christopher J. Stanley, Diane L. Damiano, and Thomas C. Bulea
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0301 basic medicine ,medicine.medical_specialty ,medicine.medical_treatment ,Kinematics ,Cerebral palsy ,03 medical and health sciences ,Behavioral Neuroscience ,0302 clinical medicine ,Physical medicine and rehabilitation ,local dynamic stability ,medicine ,Neural control ,Biological neural network ,knee angle ,neural circuits ,Biological Psychiatry ,Neurorehabilitation ,Original Research ,neurorehabilitation ,Rehabilitation ,brain injury ,medicine.disease ,after-effects ,Weighting ,Psychiatry and Mental health ,030104 developmental biology ,Neuropsychology and Physiological Psychology ,Neurology ,Physical therapy ,Motor learning ,Psychology ,030217 neurology & neurosurgery ,Neuroscience - Abstract
Motor adaptation, or alteration of neural control in response to a perturbation, is a potential mechanism to facilitate motor learning for rehabilitation. Central nervous system deficits are known to affect locomotor adaptation; yet we demonstrated that similar to adults following stroke, children with unilateral brain injuries can adapt step length in response to unilateral leg weighting. Here, we extend our analysis to explore kinematic strategies underlying step length adaptation and utilize dynamical systems approaches to elucidate how neural control may differ in those with hemiplegic CP across legs and compared to typically developing controls. Ten participants with hemiplegic CP and ten age-matched controls participated in this study. Knee and hip joint kinematics were analyzed during unilateral weighting of each leg in treadmill walking to assess adaptation and presence and persistence of after-effects. Peak joint angle displacement was used to represent changes in joint angles during walking. We examined baseline and task-specific variability and local dynamic stability to evaluate neuromuscular control across groups and legs. In contrast to controls, children with unilateral CP had asymmetries in joint angle variability and local dynamic stability at baseline, showing increased variability and reduced stability in the dominant limb. Kinematic variability increased and local stability decreased during weighting of ipsilateral and contralateral limbs in both groups compared to baseline. After weight removal both measures returned to baseline. Analogous to the temporal-spatial results, children with unilateral CP demonstrated similar capability as controls to adapt kinematics to unilateral leg weighting, however, the group with CP differed across sides after weight removal with dominant limb after-effects fading more quickly than in controls. The change in kinematics did not completely return to baseline in the non-dominant limb of the CP group, producing a transient improvement in joint angle symmetry. Recent studies demonstrate that neural control of gait is multi-layered with distinct circuits for different types of walking and for each leg. Remarkably, our results demonstrate that children with unilateral brain injury retain these separate circuits for each leg during walking and, importantly, that those networks can be adapted independently from one another to improve symmetry in the short term.
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- 2017
20. Motor Learning Abilities Are Similar in Hemiplegic Cerebral Palsy Compared to Controls as Assessed by Adaptation to Unilateral Leg-Weighting during Gait: Part I
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Thomas C. Bulea, Christopher J. Stanley, Diane L. Damiano, and Hyung-Soon Park
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030506 rehabilitation ,medicine.medical_specialty ,Cerebellum ,cerebellar deficits ,Traumatic brain injury ,Cerebral palsy ,03 medical and health sciences ,Behavioral Neuroscience ,aftereffects ,0302 clinical medicine ,Physical medicine and rehabilitation ,children ,medicine ,Treadmill ,Biological Psychiatry ,Original Research ,Hemiplegic cerebral palsy ,business.industry ,medicine.disease ,brain injury ,Weighting ,Psychiatry and Mental health ,Neuropsychology and Physiological Psychology ,medicine.anatomical_structure ,Neurology ,Physical therapy ,0305 other medical science ,Psychology ,business ,Motor learning ,Accommodation ,030217 neurology & neurosurgery ,asymmetry ,Neuroscience - Abstract
Introduction: Individuals with cerebral palsy (CP) demonstrate high response variability to motor training insufficiently accounted for by age or severity. We propose here that differences in the inherent ability to learn new motor tasks may explain some of this variability. Damage to motor pathways involving the cerebellum, which may be a direct or indirect effect of the brain injury for many with CP, has been shown to adversely affect the ability to learn new motor tasks and may be a potential explanation. Classic adaptation paradigms that evaluate cerebellar integrity have been utilized to assess adaptation to gait perturbations in adults with stroke, traumatic brain injury and other neurological injuries but not in children with CP. Materials and Methods: A case-control study of 10 participants with and 10 without hemiplegic CP within the age range of 5–20 years was conducted. Mean age of participants in the CP group was slightly but not significantly higher than controls. Step length and swing time adaptation, defined as gradual accommodation to a perturbation, and aftereffects, or maintenance of the accommodation upon removal of the perturbation, to unilateral leg weighing during treadmill gait were quantified to assess group differences in learning. Results: Adaptation and aftereffects were demonstrated in step length across groups with no main effect for group. In CP, the dominant leg had a greater response when either leg was weighted. Swing time accommodated immediately (no adaptation) in the weighted leg only, with the non-dominant leg instead showing a more pronounced response in CP. Discussion: This group of participants with unilateral CP did not demonstrate poorer learning or retention similar to reported results in adult stroke. Deficits, while not found here, may become evident in those with other etiologies or greater severity of CP. Our data further corroborate an observation from the stroke literature that repeated practice of exaggerating the asymmetry (error augmentation), in this case by weighting the more involved or shorter step leg, vs. minimizing it by weighting the less involved or longer step leg (error reduction) may be a useful training strategy to improve step symmetry in unilateral CP.
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- 2017
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21. Effects of a Knee Extension Constraint Brace on Lower Extremity Movements after ACL Reconstruction
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R. Alexander Creighton, William E. Garrett, Michael T. Gross, Christopher J. Stanley, and Bing Yu
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Adult ,Male ,musculoskeletal diseases ,medicine.medical_specialty ,Adolescent ,Sports medicine ,Anterior cruciate ligament ,Knee flexion ,Knee Injuries ,Motor Activity ,Knee extension ,Young Adult ,Physical medicine and rehabilitation ,Clinical Research ,medicine ,Humans ,Orthopedics and Sports Medicine ,Anterior Cruciate Ligament ,Range of Motion, Articular ,Ground reaction force ,Leg ,Braces ,business.industry ,Anterior Cruciate Ligament Injuries ,musculoskeletal, neural, and ocular physiology ,General Medicine ,Plastic Surgery Procedures ,musculoskeletal system ,Brace ,Constraint (information theory) ,Treatment Outcome ,surgical procedures, operative ,medicine.anatomical_structure ,Orthopedic surgery ,Physical therapy ,Female ,Surgery ,business ,human activities - Abstract
BACKGROUND: Patients have high reinjury rates after ACL reconstruction. Small knee flexion angles and large peak posterior ground reaction forces in landing tasks increase ACL loading. QUESTIONS/PURPOSES: We determined the effects of a knee extension constraint brace on knee flexion angle, peak posterior ground reaction force, and movement speed in functional activities of patients after ACL reconstruction. PATIENTS AND METHODS: Six male and six female patients 3.5 to 6.5 months after ACL reconstruction participated in the study. Three-dimensional videographic and force plate data were collected while patients performed level walking, jogging, and stair descent wearing a knee extension constraint brace, wearing a nonconstraint brace, and not wearing a knee brace. Knee flexion angle at initial foot contact with the ground, peak posterior ground reaction force, and movement speed were compared across brace conditions and between genders. RESULTS: Wearing the knee extension constraint brace increased the knee flexion angle at initial foot contact for each activity when compared with the other two brace conditions. Wearing the knee extension constraint brace also decreased peak posterior ground reaction force during walking but not during jogging and stair descent. CONCLUSIONS: Although the knee extension constraint brace did not consistently reduce the peak posterior ground reaction force in all functional activities, it consistently increased knee flexion angle and should reduce ACL loading as suggested by previous studies. These results suggest the knee extension constraint brace has potential as a rehabilitation tool to alter lower extremity movement patterns of patients after ACL reconstruction to address high reinjury rates.
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- 2011
22. Prefrontal, posterior parietal and sensorimotor network activity underlying speed control during walking
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Thomas C. Bulea, Diane L. Damiano, Jonghyun Kim, Hyung-Soon Park, and Christopher J. Stanley
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source localization ,Poison control ,Posterior parietal cortex ,gait ,lcsh:RC321-571 ,Premotor cortex ,Behavioral Neuroscience ,Gait (human) ,motor cortex ,medicine ,lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry ,Biological Psychiatry ,Original Research ,neurorehabilitation ,Motor control ,Preferred walking speed ,Psychiatry and Mental health ,medicine.anatomical_structure ,Neuropsychology and Physiological Psychology ,Neurology ,electroencephalography ,motorlearning ,gamma oscillations ,event-related desynchronization ,Motor learning ,Psychology ,Neuroscience ,motor learning ,Cortical Synchronization - Abstract
Accumulating evidence suggests cortical circuits may contribute to control of human locomotion. Here, noninvasive electroencephalography (EEG) recorded from able-bodied volunteers during a novel treadmill walking paradigm was used to assess neural correlates of walking. A systematic processing method, including a recently developed subspace reconstruction algorithm, reduced movement-related EEG artifact prior to independent component analysis and dipole source localization. We quantified cortical activity while participants tracked slow and fast target speeds across two treadmill conditions: an active mode that adjusted belt speed based on user movements and a passive mode reflecting a typical treadmill. Our results reveal frequency specific, multi-focal task related changes in cortical oscillations elicited by active walking. Low gamma band power, localized to the prefrontal and posterior parietal cortices, was significantly increased during double support and early swing phases, critical points in the gait cycle since the active controller adjusted speed based on pelvis position and swing foot velocity. These phasic gamma band synchronizations provide evidence that prefrontal and posterior parietal networks, previously implicated in visuo-spatial and somotosensory integration, are engaged to enhance lower limb control during gait. Sustained mu and beta band desynchronization within sensorimotor cortex, a neural correlate for movement, was observed during walking thereby validating our methods for isolating cortical activity. Our results also demonstrate the utility of EEG recorded during locomotion for probing the multi-regional cortical networks which underpin its execution. For example, the cortical network engagement elicited by the active treadmill suggests that it may enhance neuroplasticity for more effective motor training.
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- 2015
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23. Functional Near Infrared Spectroscopy of the Sensory and Motor Brain Regions with Simultaneous Kinematic and EMG Monitoring During Motor Tasks
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Ana Carolina de Campos, Theresa Sukal-Moulton, Christopher J. Stanley, and Diane L. Damiano
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medicine.medical_specialty ,Movement disorders ,Computer science ,Brain activity and meditation ,Movement ,General Chemical Engineering ,Electromyography ,Brain mapping ,General Biochemistry, Genetics and Molecular Biology ,Cerebral palsy ,Gait (human) ,Physical medicine and rehabilitation ,medicine ,Humans ,Gait ,Brain Mapping ,Behavior ,Spectroscopy, Near-Infrared ,General Immunology and Microbiology ,medicine.diagnostic_test ,General Neuroscience ,Motor control ,Hand ,medicine.disease ,Bicycling ,Biomechanical Phenomena ,Physical therapy ,Functional near-infrared spectroscopy ,Sensorimotor Cortex ,medicine.symptom - Abstract
There are several advantages that functional near-infrared spectroscopy (fNIRS) presents in the study of the neural control of human movement. It is relatively flexible with respect to participant positioning and allows for some head movements during tasks. Additionally, it is inexpensive, light weight, and portable, with very few contraindications to its use. This presents a unique opportunity to study functional brain activity during motor tasks in individuals who are typically developing, as well as those with movement disorders, such as cerebral palsy. An additional consideration when studying movement disorders, however, is the quality of actual movements performed and the potential for additional, unintended movements. Therefore, concurrent monitoring of both blood flow changes in the brain and actual movements of the body during testing is required for appropriate interpretation of fNIRS results. Here, we show a protocol for the combination of fNIRS with muscle and kinematic monitoring during motor tasks. We explore gait, a unilateral multi-joint movement (cycling), and two unilateral single-joint movements (isolated ankle dorsiflexion, and isolated hand squeezing). The techniques presented can be useful in studying both typical and atypical motor control, and can be modified to investigate a broad range of tasks and scientific questions.
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- 2014
24. Low-cost implementation of a self-paced treadmill by using a commercial depth sensor
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Hyung-Soon Park, Andrew J. Gravunder, Jonghyun Kim, and Christopher J. Stanley
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Adult ,Male ,Depth Perception ,Engineering ,business.industry ,Healthy subjects ,Biofeedback, Psychology ,Pilot Projects ,Instrumented treadmill ,Treadmill training ,Motion capture ,Healthy Volunteers ,Gait (human) ,Gait analysis ,Costs and Cost Analysis ,Exercise Test ,Humans ,Female ,Treadmill ,business ,Gait ,Wireless Technology ,Self paced ,Simulation ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
A self-paced treadmill that can simulate overground walking has the potential to improve the effectiveness of treadmill training for gait rehabilitation. We have implemented a self-paced treadmill without the need for expensive equipment such as a motion capture system and an instrumented treadmill. For this, an inexpensive depth sensor, ASUS XtionTM, substitutes for the motion capture system, and a low-cost commercial treadmill is considered as the platform of the self-paced treadmill. The proposed self-paced treadmill is also convenient because the depth sensor does not require markers placed on user's body. Through pilot tests with two healthy subjects, it is quantitatively and qualitatively verified that the proposed self-paced treadmill achieves similar performance as one which utilizes a commercial motion capture system (VICON) as well as an instrumented treadmill.
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- 2013
25. A user-driven treadmill control scheme for simulating overground locomotion
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Lindsey A. Curatalo, Christopher J. Stanley, Hyung-Soon Park, and Jonghyun Kim
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Male ,Scheme (programming language) ,Engineering ,business.industry ,Overground walking ,Walking ,Swing ,Article ,Biomechanical Phenomena ,User driven ,Acceleration ,Gait analysis ,Fictitious force ,Humans ,Female ,Treadmill ,business ,computer ,Locomotion ,Simulation ,ComputingMethodologies_COMPUTERGRAPHICS ,computer.programming_language - Abstract
Treadmill-based locomotor training should simulate overground walking as closely as possible for optimal skill transfer. The constant speed of a standard treadmill encourages automaticity rather than engagement and fails to simulate the variable speeds encountered during real-world walking. To address this limitation, this paper proposes a user-driven treadmill velocity control scheme that allows the user to experience natural fluctuations in walking velocity with minimal unwanted inertial force due to acceleration/deceleration of the treadmill belt. A smart estimation limiter in the scheme effectively attenuates the inertial force during velocity changes. The proposed scheme requires measurement of pelvic and swing foot motions, and is developed for a treadmill of typical belt length (1.5 m). The proposed scheme is quantitatively evaluated here with four healthy subjects by comparing it with the most advanced control scheme identified in the literature.
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- 2012
26. A Practical Strategy for sEMG-Based Knee Joint Moment Estimation During Gait and Its Validation in Individuals With Cerebral Palsy
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Jung Kim, Suncheol Kwon, Diane L. Damiano, Hyung-Soon Park, Christopher J. Stanley, and Jonghyun Kim
- Subjects
musculoskeletal diseases ,Male ,Engineering ,medicine.medical_specialty ,Adolescent ,Knee Joint ,Biomedical Engineering ,Models, Biological ,Article ,Inverse dynamics ,Physical medicine and rehabilitation ,medicine ,Humans ,Ground reaction force ,Child ,Gait ,Optimal estimation ,business.industry ,Electromyography ,Cerebral Palsy ,Biomechanics ,Reproducibility of Results ,Signal Processing, Computer-Assisted ,Biomechanical Phenomena ,Moment (mathematics) ,Gait analysis ,Physical therapy ,Female ,business ,Muscle Contraction - Abstract
Individuals with cerebral palsy have neurological deficits that may interfere with motor function and lead to abnormal walking patterns. It is important to know the joint moment generated by the patient's muscles during walking in order to assist the suboptimal gait patterns. In this paper, we describe a practical strategy for estimating the internal moment of a knee joint from surface electromyography (sEMG) and knee joint angle measurements. This strategy requires only isokinetic knee flexion and extension tests to obtain a relationship between the sEMG and the knee internal moment, and it does not necessitate comprehensive laboratory calibration, which typically requires a 3-D motion capture system and ground reaction force plates. Four estimation models were considered based on different assumptions about the functions of the relevant muscles during the isokinetic tests and the stance phase of walking. The performance of the four models was evaluated by comparing the estimated moments with the gold standard internal moment calculated from inverse dynamics. The results indicate that an optimal estimation model can be chosen based on the degree of cocontraction. The estimation error of the chosen model is acceptable (normalized root-mean-squared error: 0.15-0.29, R: 0.71-0.93) compared to previous studies (Doorenbosch and Harlaar, 2003; Doorenbosch and Harlaar, 2004; Doorenbosch, Joosten, and Harlaar, 2005), and this strategy provides a simple and effective solution for estimating knee joint moment from sEMG.
- Published
- 2012
27. Homogeneous Assay for Tyrosine Kinase: Use of Bacteriophage Antibody Conjugates in an Assay for p56lck Kinase
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Stuart Mark Wilson, Christopher J. Stanley, and Jay Patel
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chemistry.chemical_classification ,Fluorophore ,Kinase ,Drug discovery ,Biochemistry (medical) ,Clinical Biochemistry ,Peptide ,Biology ,Phosphorylated Peptide ,chemistry.chemical_compound ,Förster resonance energy transfer ,chemistry ,Biochemistry ,Phosphorylation ,Tyrosine kinase - Abstract
Protein kinases play a critical role in almost every cellular regulatory process and have been identified as key players in diseases such as cancer and immune syndromes (1). For this reason, there has been substantial interest in the development of assays for protein kinases for use as both diagnostics and drug discovery tools (2). Although several assays exist for kinases, the most commonly used involve monitoring transfer of the γ-phosphoryl group from [γ-32P]ATP to a peptide substrate (3). These assays are cumbersome to implement because the unreacted [γ-32P]ATP needs to be separated from the phosphorylated peptide by use of separation techniques such as gel electrophoresis. In drug discovery programs, fluorescence resonance energy transfer (FRET) kinase assays are becoming increasingly popular because they are homogeneous, making them relatively easy to automate (4). In typical FRET assays, the anti-phosphotyrosine antibody and the substrate peptide are labeled with “donor” and “acceptor” fluorophores. On phosphorylation of the peptide, the anti-phosphotyrosine antibody binds to the peptide, and the two fluorophores are brought in close proximity to each other. Excitation of the acceptor fluorophore leads to energy transfer to the donor molecule, which emits fluorescence. The principal disadvantage of FRET-based assays is that they are difficult to configure because the two fluorophores need to be within a closely defined distance of each other. The Dual Phage technology is a new ultrasensitive biological amplification system of broad applicability that uses bacteriophages as …
- Published
- 2002
28. Comparison of elliptical training, stationary cycling, treadmill walking and overground walking
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Diane L. Damiano, Hyung-Soon Park, Tracy L. Norman, and Christopher J. Stanley
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Adult ,Male ,medicine.medical_specialty ,Power walking ,Biophysics ,Kinematics ,Walking ,Article ,Young Adult ,Gait (human) ,Physical medicine and rehabilitation ,Gait training ,Locomotor rhythm ,medicine ,Humans ,Orthopedics and Sports Medicine ,Neurorehabilitation ,business.industry ,Rehabilitation ,Bicycling ,Biomechanical Phenomena ,Exercise Therapy ,Lower Extremity ,Physical therapy ,Female ,Cadence ,Cycling ,business ,human activities - Abstract
The extent to which therapeutic, exercise or robotic devices can maximize gait function is a major unresolved issue in neurorehabilitation. Several factors may influence gait outcomes such as similarity of the task to overground walking, degree of coordination within and across limbs, and cycle-to-cycle variability in each device. Our objective was to compare lower extremity kinematics, coordination and variability during four locomotor tasks: overground walking, treadmill walking, elliptical training and stationary cycling in 10 non-disabled adults (6 male; mean age 22.7±2.9 yrs, range 20-29). All first performed four overground walking trials at self-selected speed with mean temporal-spatial data used to pace the other conditions. Joint positions, excursions, and the Gait Deviation Index (GDI) were compared across conditions to evaluate kinematic similarity. Time-series data were correlated within and across limbs to evaluate intralimb and interlimb coordination, respectively. Variability in cadence was quantified to assess how constrained the locomotor rhythm was compared to overground walking. Treadmill walking most closely resembled overground with GDI values nearly overlapping, reinforcing its appropriateness for gait training. Cycling showed the largest GDI difference from overground, with elliptical closer but still a significant distance from all three. Cycling showed greater hip reciprocation Cycling and elliptical showed stronger intralimb synergism at the hip and knee than the other two. Based on kinematics, results suggest that elliptical training may have greater transfer to overground walking than cycling and cycling may be more useful for enhancing reciprocal coordination. Further evaluation of these devices in neurological gait disorders is needed.
- Published
- 2010
29. Comparison of elliptical training, stationary cycling, treadmill walking and overground walking. Electromyographic patterns
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Tracy L. Norman, Diane L. Damiano, Hyung S. Park, Laura A. Prosser, and Christopher J. Stanley
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Adult ,Male ,medicine.medical_specialty ,medicine.medical_treatment ,Biophysics ,Kinematics ,Electromyography ,Walking ,Article ,Physical medicine and rehabilitation ,Gait training ,Medicine ,Humans ,Orthopedics and Sports Medicine ,Muscle, Skeletal ,Rehabilitation ,medicine.diagnostic_test ,business.industry ,Work (physics) ,Repeated measures design ,musculoskeletal system ,Coactivation ,Gait ,Biomechanical Phenomena ,Kinetics ,Physical therapy ,Exercise Test ,Female ,business - Abstract
The most common functional motor goal of lower extremity rehabilitation is to improve walking ability. For reasons of feasibility, safety or intensity, devices are frequently used to facilitate or augment gait training. The objective of this study was to compare the muscle activity patterns of the rectus femoris and semitendinosus muscles during four conditions: overground walking, treadmill walking, stationary cycling, and elliptical training. Ten healthy adults (six male, four female; mean age 22.7±2.9 years, range 20-29) participated and surface electromyographic data were recorded. Linear envelope curves were generated and time normalized from 0 to 100% cycle. The mean plus three standard deviations from a static trial was used as the threshold for muscle activity. Repeated measures analysis of variance procedures were used to detect differences between conditions. Elliptical training demonstrated greater rectus femoris activity and greater rectus femoris/semitendinosus coactivation than all other conditions. Consistent with previous work, treadmill walking demonstrated greater rectus femoris activity than overground walking. Minimal differences in semitendinosus activation were observed between conditions, limited to lower peak activity during cycling compared to treadmill walking. These results provide normative values for rectus femoris and semitendinosus activation for different locomotor training methods and may assist in selecting the most appropriate training device for specific patients. Clinicians and researchers should also consider the kinematic and kinetic differences between tasks, which cannot necessarily be inferred from muscle activation patterns.
- Published
- 2010
30. The LiMA technology: measurement of ATP on a nucleic acid testing platform
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Sharon Banin, Stuart Mark Wilson, and Christopher J. Stanley
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chemistry.chemical_classification ,DNA, Bacterial ,DNA ligase ,Bacteriological Techniques ,Staphylococcus aureus ,DNA Ligases ,Oligonucleotide ,Biochemistry (medical) ,Clinical Biochemistry ,Biology ,Luciferin ,Pyrophosphate ,Polymerase Chain Reaction ,chemistry.chemical_compound ,Enzyme ,Adenosine Triphosphate ,chemistry ,Biochemistry ,Nat ,Nucleotide ,Luciferase ,DNA Breaks, Single-Stranded - Abstract
Detection of bacterial growth is used in the diagnosis and treatment of infectious disease, blood screening, food safety, product quality assurance, and life science research. The measurement of intracellular ATP content has long been the standard for rapid bacterial growth and viability measurement (1)(2)(3). The current methods used to detect ATP include luminescence generated by the enzyme system firefly luciferase/luciferin. The chemistry involved in this process is simple and can be used with a wide range of luminescence equipment, from handheld devices to sophisticated, laboratory-based instruments for high-throughput applications(4). We have developed an alternative, quantitative assay method for ATP based on a nucleic acid testing (NAT) format. During the past decade NAT has become the method of choice for bacterial identification (5). NAT hardware, such as thermal cyclers, isothermal instruments, and real-time/kinetic product detection systems, are now commonplace laboratory equipment. The new method, LiMA (Ligase Mediated ATP Amplification Assay)(6), uses DNA ligase, an ATP-requiring enzyme(7), to join 2 oligonucleotides in a nicked-DNA substrate and create a template that can be amplified in a DNA amplification reaction (Fig. 1⇓ ). Before the LiMA process, the ligase is treated with pyrophosphate to ensure that all the enzyme molecules are in the deadenylated form. Thus the ligase is inactive until it binds a molecule of ATP, which leads to the loss of the pyrophosphate moiety from ATP and the formation of a covalent enzyme—AMP intermediate linked to a lysine side-chain in the enzyme. In this reaction the enzyme becomes charged by an ATP molecule; essentially, a sample is scavenged for its ATP content. In the next step of the reaction the AMP nucleotide is transferred to the 5′ phosphate of the nicked-DNA strand, followed by attack on the AMP-DNA bond by the 3′-OH of …
- Published
- 2007
31. Demonstration of an alternative approach to immuno-PCR
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Stuart Mark Wilson, Christopher J. Stanley, and Sharon Banin
- Subjects
Exonuclease ,Streptavidin ,Clinical Biochemistry ,Enzyme-Linked Immunosorbent Assay ,Polymerase Chain Reaction ,Sensitivity and Specificity ,law.invention ,chemistry.chemical_compound ,Adapter (genetics) ,law ,medicine ,Animals ,Polymerase chain reaction ,biology ,medicine.diagnostic_test ,Biochemistry (medical) ,Reproducibility of Results ,Nucleic acid amplification technique ,Alkaline Phosphatase ,chemistry ,Biochemistry ,Immunoassay ,Nucleic acid ,biology.protein ,Cattle ,DNA - Abstract
There have been many reports describing the combination of immunoassay techniques and nucleic acid amplification using antibodies labeled directly with nucleic acids (the “direct” immuno-PCR approach) (1)(2)(3). The rationale behind immuno-PCR is to develop ultrahigh-sensitivity labels by exploiting the extremely high productivity of nucleic acid amplification techniques, coupled with highly sensitive approaches to detect the amplified material. Specific applications in which the use of ultrahigh-sensitivity immuno-PCR techniques have been proposed include prion protein detection, in which there is no nucleic acid associated with the infectious agent, and the detection of viral antigens in blood bank screening applications, in which there can be very little viral nucleic acid present at certain stages of the infection. Although the principle of immuno-PCR has been demonstrated in various research applications, there are continuing concerns over both the technical difficulty of linking nucleic acids directly to antibodies (or “adapter” proteins such as streptavidin) and the substantial backgrounds that can be generated by nonspecific binding of the nucleic acid–antibody conjugates to solid phases (2)(4). We have developed an alternative approach based on an “indirect” immuno-PCR technique that links ELISA techniques and PCR. Because this approach works in a completely different way to traditional immuno-PCR, it may circumvent some of the problems associated with the traditional approach. Here we present the proof of principle of our new approach. We used a double stranded 5′-phosphorylated DNA (dsDNA) substrate for alkaline phosphatase (AP). Shown in Fig. 1A⇓ is a schematic of the principle of the enzyme assay method. The procedure takes advantage of the substrate specificity of λ exonuclease for the 5′-phosphorylated form of dsDNA (5). In an immunometric assay, the AP in the antibody conjugate will remove the 5′ phosphate groups, and the DNA …
- Published
- 2004
32. Contribution of hip joint proprioception to static and dynamic balance in cerebral palsy: a case control study
- Author
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Diane L. Damiano, Lindsey A. Curatalo, Jason R. Wingert, and Christopher J. Stanley
- Subjects
Male ,medicine.medical_specialty ,Hemiplegia ,Health Informatics ,Diplegia ,Sensory function ,Cerebral palsy ,Physical medicine and rehabilitation ,medicine ,Humans ,Dynamic balance ,Postural Balance ,Static balance ,Balance (ability) ,Sroprioception ,Proprioception ,Cerebral Palsy ,Research ,Rehabilitation ,Motor control ,Repeated measures design ,Middle Aged ,medicine.disease ,Case-Control Studies ,Female ,Hip Joint ,medicine.symptom ,Psychology ,Balance problems - Abstract
Background Balance problems are common in cerebral palsy (CP) but etiology is often uncertain. The classic Romberg test compares ability to maintain standing with eyes open versus closed. Marked instability without vision is a positive test and generally indicates proprioceptive loss. From previous work showing diminished hip joint proprioception in CP, we hypothesized that static and dynamic balance without vision (positive Romberg) would be compromised in CP. Methods Force plate sway and gait velocity data were collected using 3D motion capture on 52 participants, 19 with diplegic CP, 13 with hemiplegic CP, and 20 without disability. Center of mass (COM) and center or pressure (COP) velocity, excursion, and differences between COM and COP in AP and ML directions were computed from static standing trials with eyes open and closed. Mean gait velocity with and without dribble glasses was compared. Hip joint proprioception was quantified as the root mean square of magnitude of limb positioning errors during a hip rotation task with and without view of the limb. Mixed model repeated measures analysis of variance (ANOVA) was performed with condition as within-subject (EO, EC) and group as between-subject factors (hemiplegia, diplegia, controls). Sway characteristics and gait speed were correlated with proprioception values. Results Groups with CP had greater sway in standing with eyes open indicating that they had poorer balance than controls, with the deficit relatively greater in the ML compared to AP direction. Contrary to our hypothesis, the decrement with eyes closed did not differ from controls (negative Romberg); however, proprioception error was related to sway parameters particularly for the non-dominant leg. Gait speed was related to proprioception values such that those with worse proprioception tended to walk more slowly. Conclusions Postural instability is present even in those with mild CP and is yet another manifestation of their motor control disorder, the specific etiology of which may vary across individuals in this heterogeneous diagnostic category.
- Published
- 2013
33. Polymeric Ligands with Specificity for Aggregated Prion Proteins
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Stuart Mark Wilson, Christopher J. Stanley, Stephen Dealler, and Amin Reza Lane
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biology ,medicine.diagnostic_test ,animal diseases ,Bovine spongiform encephalopathy ,Biochemistry (medical) ,Clinical Biochemistry ,medicine.disease ,Proteinase K ,Virology ,nervous system diseases ,Western blot ,Immunoassay ,medicine ,biology.protein ,media_common.cataloged_instance ,Alzheimer's disease ,European union ,Antibody ,Protein secondary structure ,media_common - Abstract
The misfolding of normal proteins and their subsequent aggregation in the brain is characteristic of a group of related neurologic diseases, the “protein conformational disorders”, including Parkinson disease, Alzheimer disease, and the transmissible spongiform encephalopathies (TSEs) (1). The development of highly sensitive and specific diagnostic assays for these diseases is a high priority as effective therapies become available or as food safety regulations mandate the removal of infected animals from the food chain. Current test development effort in the TSE field has been focused mainly on designing screening tests for the aggregated prion proteins in bovine, ovine, and cervid brain tissue. Several immunoassays for bovine spongiform encephalopathy (BSE) have been evaluated by the European Union (EU) (2), and three are now approved for routine use in testing laboratories. Those approved include two ELISAs in the microplate format and reagents for a Western blot analysis. The abnormal, or rogue, prion protein detected by these tests is considered to be the best indicator of TSE infection (2), but the anti-prion protein antibodies used in these assays cannot distinguish the normal, globular, proteinase K-sensitive (α-helix-rich) form of the prion protein (PrPsen) from the abnormal, aggregated, and relatively proteinase K-resistant form (PrPres), in which the secondary structure is dominated by β-sheet. Thus, a complex sample preparation procedure is required to eliminate the normal prion protein in the brain homogenate before immunoassay, usually involving a proteinase K digestion step …
- Published
- 2003
34. Abstracts from the 2017–2018 Mineral Deposits Studies Group meeting
- Author
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L. Santoro, St. Tshipeng Yav, E. Pirard, A. Kaniki, G. Arfè, N. Mondillo, M. Boni, M. Joachimski, G. Balassone, A. Mormone, A. Cauceglia, W. Robb, T. L. Smith, David Currie, Finlay Stuart, John Faithfull, Adrian Boyce, C. Chelle-Michou, S. Cretella, G. Scognamiglio, M. Tarallo, F. Putzolu, F. Pirajno, Saltanat Aitbaeva, Marina Mizernaya, Boris Dyachkov, Andrew J Martin, Iain McDonald, Christopher J MacLeod, Katie McFall, Hazel M Prichard, Gawen R T Jenkin, B. Kennedy, I. McDonald, D. Tanner, L. Longridge, A. M. Borst, A. A. Finch, H. Friis, N. J. Horsburgh, P. N. Gamaletsos, J. Goettlicher, R. Steininger, K. Geraki, Jonathan Cloutier, Stephen J. Piercey, Connor Allen, Craig Storey, James Darling, Stephanie Lasalle, A. Dobrzanski, L. Kirstein, R. Walcott, I. Butler, B. Ngwenya, Andrew Dobrzanski, Simon Howard, Lore Troalen, Peter Davidson, Rachel Walcott, Drew Drummond, Robert Blakeman, John Ashton, Eva Marquis, Kathryn Goodenough, Guillaume Estrade, Martin Smith, E. Zygouri, S. P. Kilias, T. Zack, I. Pitcairn, E. Chi Fru, P. Nomikou, A. Argyraki, M. Ivarsson, Adrian A. Finch, Anouk M. Borst, William Hutchison, Nicola J. Horsburgh, Tom Andersen, Siri Simonsen, Hamidullah Waizy, Norman Moles, Steven P. Hollis, Julian F. Menuge, Aileen L. Doran, Paul Dennis, Brett Davidheiser-Kroll, Alina Marca, Jamie Wilkinson, John Güven, Mark R. Cooper, J. Stephen Daly, Oakley Turner, Brian McConnell, Hannah S. R. Hughes, Magdalena M. Matusiak-Małek, Ben Williamson, James Williams, Guy Dishaw, Harri Rees, Roger Key, Simon Bate, Andy Moore, Dominque Tanner, Manuel Keith, Karsten M. Haase, Daniel J. Smith, Reiner Klemd, Ulrich Schwarz-Schampera, Wolfgang Bach, Sam J Walding, Gawen RT Jenkin, Daniel James, David Clark, Lisa Hart-Madigan, Robin Armstrong, Hugh Graham, Daniel J Smith, Andrew P Abbott, David A Holwell, Eva Zygouri, Robert C Harris, Christopher J Stanley, Hannah L.J. Grant, Mark D. Hannington, Sven Petersen, Matthias Frische, Fei Zhang, Ben J. Williamson, Hannah Hughes, Joshua Smiles, Chetan Nathwani, Robert Sievwright, Matthew Loader, Daryl E. Blanks, David A. Holwell, W.D. Smith, J.R. Darling, D.S. Bullen, R.C. Scrivener, Adrian J. Boyce, Sam Broom-Fendley, Aoife E Brady, Karen Hudson-Edwards, Steve Hollis, Sean McClenaghan, Aileen Doran, Emily K. Fallon, Richard Brooker, and Thomas Scott
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Animal science ,Mineral ,010504 meteorology & atmospheric sciences ,Geochemistry and Petrology ,Group (periodic table) ,Earth and Planetary Sciences (miscellaneous) ,010502 geochemistry & geophysics ,Geotechnical Engineering and Engineering Geology ,01 natural sciences ,Geology ,0105 earth and related environmental sciences - Full Text
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35. Biomechanical Evaluation of Virtual Reality-based Turning on a Self-Paced Linear Treadmill.
- Author
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Oh K, Stanley CJ, Damiano DL, Kim J, Yoon J, and Park HS
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- Adult, Biomechanical Phenomena, Female, Foot physiology, Head physiology, Hip physiology, Humans, Kinetics, Male, Pelvis physiology, Rotation, Young Adult, Exercise Test, Gait physiology, Virtual Reality, Walking physiology
- Abstract
Background: Patients with brain injuries such as Parkinson's disease or stroke exhibit abnormal gait characteristics especially during gait transitions such as step initiation and turning. Since such transitions could precipitate falls and resultant injuries, evaluation and rehabilitation of non-steady state gait in those patients are important. Whereas body weight supported treadmill training (BWSTT) provides a safe and controlled environment for gait training, it is unable to adequately train for gait transitions since the typical linear treadmill does not allow for changes in walking direction and natural fluctuations in speed., Research Question: This paper verifies if the suggested virtual reality (VR) based walking interface combined with the unidirectional treadmill can stimulate the user to initiate turning gait., Methods: To validate whether initiation of turning was successfully achieved with the proposed walking system, we developed the VR-based walking interface combined with the self-paced treadmill and compared kinematics, kinetics, and muscle activation levels during the VR-based turning and over ground (OG) turning as well as between straight walking and turning within conditions., Results: Despite walking on a linear treadmill, subjects showed significant increases in head rotation, pelvic rotation, right hip abduction, left hip adduction, foot progression, medial-lateral ground reaction forces, right medial hamstring activation level, and changes in step width during the VR turn compared to straight walking., Significance: The developed VR-based turning interface can provide a safe and controlled environment for assessment of turning in healthy controls and may have a potential for assessment and training in patients with neurological disorders., Competing Interests: Conflict of interest statement Declarations of interest: none
- Published
- 2018
- Full Text
- View/download PDF
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