The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Michael J Mueller - One of the best experts on this subject based on the ideXlab platform.
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Pressure gradient and subsurface shear stress on the neuropathic forefoot
Clinical Biomechanics, 2008Co-Authors: Michael J Mueller, Donovan J Lott, Dequan ZouAbstract:Abstract Background Stresses within the neuropathic foot’s tissues can be estimated by Pressure distributions and may provide information regarding the potential for skin breakdown. The purposes of this study were to: (1) determine the magnitude of Peak plantar Pressure, Pressure time integral, Peak Pressure gradient, and Peak maximum shear stress; and (2) determine the association of these variables with one another. Methods Forefoot Peak plantar Pressure, Pressure time integral, Peak Pressure gradient, Peak maximal shear stress, and depth of Peak maximal shear stress were calculated for 16 controls, 16 people with diabetic neuropathy, and 22 people with diabetic neuropathy and a history of ulceration from Pressure assessments. Findings Peak plantar Pressure, Pressure gradient, and maximal shear stress were greater in subjects with a history of ulceration relative to control subjects (P Interpretation Although these variables are associated with one another, Peak Pressure gradient and Peak maximal shear stress provide information concerning plantar Pressure distribution and the potentially injurious internal stresses within the foot’s soft tissues. Peak Pressure gradient and Peak maximal shear stress may perhaps be more discriminating than Peak plantar Pressure alone in distinguishing between groups of individuals who are at risk for developing a foot ulcer.
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effect of Peak Pressure and Pressure gradient on subsurface shear stresses in the neuropathic foot
Journal of Biomechanics, 2007Co-Authors: Michael J Mueller, Donovan J LottAbstract:Abstract The Pressure distribution on the plantar surface of the foot may provide insights into the stresses within the subsurface tissues of patients with diabetes mellitus and peripheral neuropathy (PN) who are at risk for skin breakdown. The purposes of this study were to (1) estimate the stress distribution in the subsurface soft tissue from a measured surface Pressure distribution and determine any differences between values in the forefoot and rearfoot, and (2) determine the relationship between maximum shear stress (MSS) (magnitude and depth) and characteristics of the Pressure distribution. The measured in-shoe Pressure distributions during walking characterized by the Peak plantar Pressure and maximum Pressure gradient on the plantar surface of the feet for 20 subjects with diabetes, PN and history of a mid foot or forefoot plantar ulcer were analyzed. The effects of Peak Pressure and maximum Pressure gradient at the Peak Pressure location on the stress components in the subsurface soft tissue were studied using a potential function method to estimate the subsurface tissue stress. The calculated MSSs are larger in magnitude and located closer to the surface in the forefoot, where most skin breakdown occurs, compared to the rearfoot. In addition, the MSS (magnitude and depth) is highly correlated with the Pressure gradient ( r = - 0.77 & 0.61) and the Peak Pressure ( r = - 0.61 & 0.91). The Peak Pressure and the maximum Pressure gradient obtained from the surface Pressure distribution appear to be important variables to identify where MSSs are located in the subsurface tissues on the plantar foot that may lead to skin break down.
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generalizability of in shoe Peak Pressure measures using the f scan system
Clinical Biomechanics, 1996Co-Authors: Michael J Mueller, Michael J StrubeAbstract:Abstract In-shoe Pressure analysis can be useful in the management of a variety of foot and ankle problems, but guidelines are needed to determine the practical limitations of the measures. The primary purpose of this study was to determine the reliability of Peak plantar Pressures taken with the F-Scan system over multiple steps, sensors, and days, and using a force platform for additional calibration. Data were collected on 10 healthy subjects as they walked across a force platform for a minimum of three trials on four separate sessions that were 1 week apart. Using a mean of three steps with a single sensor on 1 day, generalizability coefficients were 0.75 for manufacturer calibration and 0.82 with force platform calibration; reliability coefficients for absolute decisions (index of dependability) were 0.60 for manufacturer calibration and 0.76 with force platform calibration. Force measures from the F-Scan and force platform were highly correlated (r = 0.93), but the absolute difference between the measures varied between sensors and over time.
Donovan J Lott - One of the best experts on this subject based on the ideXlab platform.
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Pressure gradient and subsurface shear stress on the neuropathic forefoot
Clinical Biomechanics, 2008Co-Authors: Michael J Mueller, Donovan J Lott, Dequan ZouAbstract:Abstract Background Stresses within the neuropathic foot’s tissues can be estimated by Pressure distributions and may provide information regarding the potential for skin breakdown. The purposes of this study were to: (1) determine the magnitude of Peak plantar Pressure, Pressure time integral, Peak Pressure gradient, and Peak maximum shear stress; and (2) determine the association of these variables with one another. Methods Forefoot Peak plantar Pressure, Pressure time integral, Peak Pressure gradient, Peak maximal shear stress, and depth of Peak maximal shear stress were calculated for 16 controls, 16 people with diabetic neuropathy, and 22 people with diabetic neuropathy and a history of ulceration from Pressure assessments. Findings Peak plantar Pressure, Pressure gradient, and maximal shear stress were greater in subjects with a history of ulceration relative to control subjects (P Interpretation Although these variables are associated with one another, Peak Pressure gradient and Peak maximal shear stress provide information concerning plantar Pressure distribution and the potentially injurious internal stresses within the foot’s soft tissues. Peak Pressure gradient and Peak maximal shear stress may perhaps be more discriminating than Peak plantar Pressure alone in distinguishing between groups of individuals who are at risk for developing a foot ulcer.
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effect of Peak Pressure and Pressure gradient on subsurface shear stresses in the neuropathic foot
Journal of Biomechanics, 2007Co-Authors: Michael J Mueller, Donovan J LottAbstract:Abstract The Pressure distribution on the plantar surface of the foot may provide insights into the stresses within the subsurface tissues of patients with diabetes mellitus and peripheral neuropathy (PN) who are at risk for skin breakdown. The purposes of this study were to (1) estimate the stress distribution in the subsurface soft tissue from a measured surface Pressure distribution and determine any differences between values in the forefoot and rearfoot, and (2) determine the relationship between maximum shear stress (MSS) (magnitude and depth) and characteristics of the Pressure distribution. The measured in-shoe Pressure distributions during walking characterized by the Peak plantar Pressure and maximum Pressure gradient on the plantar surface of the feet for 20 subjects with diabetes, PN and history of a mid foot or forefoot plantar ulcer were analyzed. The effects of Peak Pressure and maximum Pressure gradient at the Peak Pressure location on the stress components in the subsurface soft tissue were studied using a potential function method to estimate the subsurface tissue stress. The calculated MSSs are larger in magnitude and located closer to the surface in the forefoot, where most skin breakdown occurs, compared to the rearfoot. In addition, the MSS (magnitude and depth) is highly correlated with the Pressure gradient ( r = - 0.77 & 0.61) and the Peak Pressure ( r = - 0.61 & 0.91). The Peak Pressure and the maximum Pressure gradient obtained from the surface Pressure distribution appear to be important variables to identify where MSSs are located in the subsurface tissues on the plantar foot that may lead to skin break down.
Martin Fergusonpell - One of the best experts on this subject based on the ideXlab platform.
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Pressure changes under the ischial tuberosities during gluteal neuromuscular stimulation in spinal cord injury a comparison of sacral nerve root stimulation with surface functional electrical stimulation
Archives of Physical Medicine and Rehabilitation, 2015Co-Authors: Liang Q Liu, Martin FergusonpellAbstract:Abstract Objective To compare the magnitude of interface Pressure changes during gluteal maximus contraction by stimulating sacral nerve roots with surface electrical stimulations in patients with spinal cord injuries (SCIs). Design Pilot interventional study. Setting Spinal injury research laboratory. Participants Adults (N=18) with suprasacral complete SCI. Interventions Sacral nerve root stimulation (SNRS) via a functional magnetic stimulator (FMS) or a sacral anterior root stimulator (SARS) implant; and surface functional electrical stimulation (FES). Main Outcome Measures Interface Pressure under the ischial tuberosity (IT) defined as Peak Pressure, gradient at Peak Pressure, and average Pressure. Results With optimal FMS, a 29% average reduction of IT Peak Pressure was achieved during FMS (mean ± SD: 160.1±24.3mmHg at rest vs 114.7±18.0mmHg during FMS, t 5 =6.3, P =.002). A 30% average reduction of Peak Pressure during stimulation via an SARS implant (143.2±31.7mmHg at rest vs 98.5±21.5mmHg during SARS, t 5 =4.4, P =.007) and a 22% average decrease of IT Peak Pressure during FES stimulation (153.7±34.8mmHg at rest vs 120.5±26.1mmHg during FES, t 5 =5.3, P =.003) were obtained. In 4 participants who completed both the FMS and FES studies, the percentage of Peak Pressure reduction with FMS was slightly greater than with FES (mean difference, 7.8%; 95% confidence interval, 1.6%–14.0; P =.04). Conclusions SNRS or surface FES can induce sufficient gluteus maximus contraction and significantly reduce ischial Pressure. SNRS via an SARS implant may be more convenient and efficient for frequently activating the gluteus maximus.
Robert M. Kacmarek - One of the best experts on this subject based on the ideXlab platform.
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Peak volume history and Peak Pressure volume curve Pressures independently affect the shape of the Pressure volume curve of the respiratory system
Critical Care Medicine, 2004Co-Authors: Tomoyo Nishida, Klaudiusz Suchodolski, Guilherme Schettino, Khaled Sedeek, Muneyuki Takeuch, Robert M. KacmarekAbstract:Objective:To determine the specific effect of Peak volume history Pressure on the inflation limb of the Pressure-volume curve and Peak Pressure-volume curve Pressure on the deflation limb of the Pressure-volume curve.Design:Prospective assessment of Pressure-volume curves in saline, lung lavage inju
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Peak Pressure during volume history and Pressure volume curve measurement affects analysis
American Journal of Respiratory and Critical Care Medicine, 2001Co-Authors: Muneyuki Takeuchi, Guilherme Schettino, Klaudiusz Suchodolski, Khaled Sedeek, Robert M. KacmarekAbstract:A previous volume history should be established prior to Pressure– volume (P–V) curve measurement, however the effect of the volume history and the Peak inspiratory Pressure (PIP) during the P–V measurement has not been explored. Lung injury was created by lavage in nine sheep (25–35 kg). After stabilization, four P–V curves were sequentially obtained with PIP of 40, 50, 60, and 40 cm H2O. Prior to each P–V measurement the PIP delivered for 1 min was the same as during P–V measurement. We compared the lower inflection point (Pflex), upper inflection point (UIP), compliance below Pflex (Cstart), compliance between Pflex and UIP (Cinf), and compliance between UIP and Peak Pressure (Cend) for the inflation limb, and the point of maximum curvature on the deflation limb (Pmc), compliance between Peak Pressure and Pmc (Ctop), and maximum compliance (Cdef) for the deflation limb. In two sheep, Pflex at PIP 40 cm H2O could not be identified but appeared when PIP was raised. Pflex, Cstart, Cend, and Ctop were not ...
Liang Q Liu - One of the best experts on this subject based on the ideXlab platform.
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Pressure changes under the ischial tuberosities during gluteal neuromuscular stimulation in spinal cord injury a comparison of sacral nerve root stimulation with surface functional electrical stimulation
Archives of Physical Medicine and Rehabilitation, 2015Co-Authors: Liang Q Liu, Martin FergusonpellAbstract:Abstract Objective To compare the magnitude of interface Pressure changes during gluteal maximus contraction by stimulating sacral nerve roots with surface electrical stimulations in patients with spinal cord injuries (SCIs). Design Pilot interventional study. Setting Spinal injury research laboratory. Participants Adults (N=18) with suprasacral complete SCI. Interventions Sacral nerve root stimulation (SNRS) via a functional magnetic stimulator (FMS) or a sacral anterior root stimulator (SARS) implant; and surface functional electrical stimulation (FES). Main Outcome Measures Interface Pressure under the ischial tuberosity (IT) defined as Peak Pressure, gradient at Peak Pressure, and average Pressure. Results With optimal FMS, a 29% average reduction of IT Peak Pressure was achieved during FMS (mean ± SD: 160.1±24.3mmHg at rest vs 114.7±18.0mmHg during FMS, t 5 =6.3, P =.002). A 30% average reduction of Peak Pressure during stimulation via an SARS implant (143.2±31.7mmHg at rest vs 98.5±21.5mmHg during SARS, t 5 =4.4, P =.007) and a 22% average decrease of IT Peak Pressure during FES stimulation (153.7±34.8mmHg at rest vs 120.5±26.1mmHg during FES, t 5 =5.3, P =.003) were obtained. In 4 participants who completed both the FMS and FES studies, the percentage of Peak Pressure reduction with FMS was slightly greater than with FES (mean difference, 7.8%; 95% confidence interval, 1.6%–14.0; P =.04). Conclusions SNRS or surface FES can induce sufficient gluteus maximus contraction and significantly reduce ischial Pressure. SNRS via an SARS implant may be more convenient and efficient for frequently activating the gluteus maximus.
