Biomedical Engineering and Bioengineering Commons^™

Bone Material Properties In Osteogenesis Imperfecta: A Matter Of Quantity Over Quality, Carolyne Albert, John Jameson, Gerald F. Harris, Peter Smith

Biomedical Engineering Faculty Research and Publications

No abstract provided.

A North American Consortium On Rehabilitation Engineering And Technology For The Individual, Barbara Silver-Thorn, Jessica Lothman, Terence Miller

Biomedical Engineering Faculty Research and Publications

The availability and accessibility of appropriate rehabilitative healthcare, medical technology and treatment is an important national and international issue of particular relevance due to recent national healthcare reform initiatives. The focus of this project was to increase global competencies and awareness among biomedical engineers of the differing rehabilitative healthcare needs in North America via student exchange with consortium institutions in the U.S., Canada and Mexico. The aim was to increase understanding of alternative healthcare delivery systems with respect to technology and interaction with diverse client populations in a clinical setting and to enhance the development and technology transfer of new …

Developing An At-Home System For Evaluating Manual Wheelchair Propulsion And Directing Rehabilitative Training To Optimize Biomechanical Efficiency, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Impedance Control And Internal Model Formation When Reaching In A Randomly Varying Dynamical Environment, C. D. Takahashi, Robert A. Scheidt, D. J. Reikensmeyer

Biomedical Engineering Faculty Research and Publications

We investigated the effects of trial-to-trial, random variation in environmental forces on the motor adaptation of human subjects during reaching. Novel sequences of dynamic environments were applied to subjects' hands by a robot. Subjects reached first in a “mean field” having a constant gain relating force and velocity, then in a “noise field,” having a gain that varied randomly between reaches according to a normal distribution with a mean identical to that of the mean field. The unpredictable nature of the noise field did not degrade adaptation as quantified by final kinematic error and rate of adaptation. To achieve this …

The Arm Motion (Amd) Detection Test, Maria C. Bengston, Leigh A. Mrotek, Tina M. Stoeckmann, Claude Ghez, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Stroke can lead to sensory deficits that impair functional control of arm movements. Here we describe a simple test of arm motion detection (AMD) that provides an objective, quantitative measure of movement perception related proprioceptive capabilities in the arm. Seven stroke survivors and thirteen neurologically intact control subjects performed the AMD test. In a series of ten trials that took less than 15 minutes to complete, participants used a two-button user interface to adjust the magnitude of hand displacements produced by a horizontal planar robot until the motions were just perceptible (i.e. on the threshold of detection). The standard deviation …

A Modular Low-Clearance Wrist Orthosis For Improving Wrist Motion In Children With Cerebral Palsy, Devon Holley, Michelle Johnson, Gerald F. Harris, Scott A. Beardsley

Biomedical Engineering Faculty Research and Publications

Children with Cerebral Palsy (CP) often exhibit impairments in the coordination of the grip and lift phases of arm movements that directly impact their ability to perform activities of daily living (ADLs). The application of assistive robotic therapy to children with spastic hemiplegic CP has shown that augmented movement training can lead to improved functional outcomes and improved arm kinematics. Assistive robotic therapy of the wrist has been shown to help improve motor skills in stroke patients, but the devices employed are often large and obtrusive, focusing on a repeated motion rather than a task-based itinerary. Here, we propose a …

Emerging Optical Techniques For Detection Of Oral, Cervical And Anal Cancer In Low-Resource Settings, Bing Yu, Daron G. Ferris, Yang Liu, Vivek K. Nagarajan

Biomedical Engineering Faculty Research and Publications

Cancers of the oral and anogenital regions are a growing global health problem that disproportionately impact women and men living in developing countries. The high death rate in developing countries is largely due to the fact that these countries do not have the appropriate medical infrastructure and resources to support the organized screening and diagnostic programs that are available in the developed world. Emerging optical diagnostics techniques, such as optical spectroscopy, reflectance imaging, and fluorescence imaging, are noninvasive techniques that are sensitive to multiple cancer biomarkers and have shown the potential as a cost–effective and fast tool for diagnosis of …

Which Design And Biomaterial Factors Affect Clinical Wear Performance Of Total Disc Replacements? A Systematic Review, Sai Y. Veruva, Marla J. Steinbeck, Jeffrey M. Toth, Dominik D. Alexander, Steven M. Kurtz

Biomedical Engineering Faculty Research and Publications

Background

Total disc replacement was clinically introduced to reduce pain and preserve segmental motion of the lumbar and cervical spine. Previous case studies have reported on the wear and adverse local tissue reactions around artificial prostheses, but it is unclear how design and biomaterials affect clinical outcomes.

Questions/purposes

Which design and material factors are associated with differences in clinical wear performance (implant wear and periprosthetic tissue response) of (1) lumbar and (2) cervical total disc replacements?

Methods

We performed a systematic review on the topics of implant wear and periprosthetic tissue response using an advanced search in MEDLINE and Scopus …

The Effects Of Gantry Tilt On Breast Dose And Image Noise In Cardiac Ct, Michael Hoppe, Diksha Gandhi, Grant Stevens, Dennis Foley, Taly Gilat-Schmidt

Biomedical Engineering Faculty Research and Publications

Purpose:

This study investigated the effects of tilted-gantry acquisition on image noise and glandular breast dose in females during cardiac computed tomography (CT) scans. Reducing the dose to glandular breast tissue is important due to its high radiosensitivity and limited diagnostic significance in cardiac CT scans.

Methods:

Tilted-gantry acquisition was investigated through computer simulations and experimental measurements. Upon IRB approval, eight voxelized phantoms were constructed from previously acquired cardiac CT datasets. Monte Carlo simulations quantified the dose deposited in glandular breast tissue over a range of tilt angles. The effects of tilted-gantry acquisition on breast dose were measured on a …

Depleted Energy Charge And Increased Pulmonary Endothelial Permeability Induced By Mitochondrial Complex I Inhibition Are Mitigated By Coenzyme Q1 In The Isolated Perfused Rat Lung, Robert D. Bongard, Ke Yan, Raymond G. Hoffmann, Said H. Audi, Xiao Zhang, Brian J. Lindemer, Mary I. Townsley, Marilyn P. Merker

Biomedical Engineering Faculty Research and Publications

Mitochondrial dysfunction is associated with various forms of lung injury and disease that also involve alterations in pulmonary endothelial permeability, but the relationship, if any, between the two is not well understood. This question was addressed by perfusing isolated intact rat lung with a buffered physiological saline solution in the absence or presence of the mitochondrial complex I inhibitor rotenone (20 μM). Compared to control, rotenone depressed whole lung tissue ATP from 5.66±0.46 (SEM) to 2.34±0.15 µmol·g⁻¹ dry lung, with concomitant increases in the ADP:ATP and AMP:ATP ratios. Rotenone also increased lung perfusate lactate (from 12.36±1.64 to 38.62±3.14 µmol·15 …

Visuo-Proprioceptive Interactions During Adaptation Of The Human Reach, Timothy Judkins, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

We examined whether visual and proprioceptive estimates of transient (mid-reach) target capture errors contribute to motor adaptation according to the probabilistic rules of information integration used for perception. Healthy adult humans grasped and moved a robotic handle between targets in the horizontal plane while the robot generated spring-like loads that varied unpredictably from trial-to-trial. For some trials, a visual cursor faithfully tracked hand motion. In others, the handle's position was locked and subjects viewed motion of a point-mass cursor driven by hand forces. In yet other trials, cursor feedback was dissociated from hand motion or altogether eliminated. We used time- …

Characterization And Limitations Of Diffusion Tensor Imaging Metrics In The Cervical Spinal Cord In Neurologically Intact Subjects, Aditya Vedantam, Michael B. Jirjis, Brian D. Schmit, Marjorie C. Wang, John L. Ulmer, Shekar N. Kurpad

Biomedical Engineering Faculty Research and Publications

Purpose

To characterize diffusion tensor imaging (DTI) metrics across all levels of the cervical spinal cord (CSC) and to study the impact of age and signal quality on these metrics.

Materials and Methods

DTI metrics were calculated for gray matter (GM) and white matter (WM) funiculi throughout the CSC (C1–T1) in 25 healthy subjects (22-85 years old). Signal-to-noise ratios (SNRs) and mean DTI metrics were measured for the upper (C1-3), middle (C4-6) and lower (C7-T1) cervical segments. Age-related changes in DTI metrics were analyzed for the individual segment groups.

Results

Fractional anisotropy (FA), mean diffusivity (MD) and transverse apparent diffusion …

Effect Of Tilt Sensor Versus Heel Loading On Neuroprosthesis Stimulation Reliability And Timing For Individuals Post-Stroke During Level And Non- Level Treadmill Walking, M. Barbara Silver-Thorn

Biomedical Engineering Faculty Research and Publications

Study background: Non-level walking may adversely affect stimulation of neuroprostheses as initial programming is performed during level walking. The objectives of this study were to assess stimulation reliability of tilt and heel sensor-based neuroprosthesis stimulation during level and non-level walking, examine stimulation initiation and termination timing during level and non-level walking, and determine whether heel or tilt sensor-based stimulation control is more robust for non-level ambulation. Methods: Eight post-stroke individuals with drop foot who were able to actively ambulate within the community were selected for participation. Each subject acclimated to the neuroprosthesis and walked on a treadmill randomly positioned in …

Neural Dynamics Of Phonological Processing In The Dorsal Auditory Stream, Einat Liebenthal, Merav Sabri, Scott A. Beardsley, Jain Mangalathu-Arumana, Anjali Desai

Biomedical Engineering Faculty Research and Publications

Neuroanatomical models hypothesize a role for the dorsal auditory pathway in phonological processing as a feedforward efferent system (Davis and Johnsrude, 2007; Rauschecker and Scott, 2009; Hickok et al., 2011). But the functional organization of the pathway, in terms of time course of interactions between auditory, somatosensory, and motor regions, and the hemispheric lateralization pattern is largely unknown. Here, ambiguous duplex syllables, with elements presented dichotically at varying interaural asynchronies, were used to parametrically modulate phonological processing and associated neural activity in the human dorsal auditory stream. Subjects performed syllable and chirp identification tasks, while event-related potentials and …

Hypoxia Preconditioning Increases Survival And Decreases Expression Of Toll-Like Receptor 4 In Pulmonary Artery Endothelial Cells Exposed To Lipopolysaccharide, Irshad Ali, Rahul Nanchal, Fouad Husnain, Said H. Audi, G. Ganesh Konduri, John C. Densmore, Meetha Medhora, Elizabeth R. Jacobs

Biomedical Engineering Faculty Research and Publications

Pulmonary or systemic infections and hypoxemic respiratory failure are among the leading causes of admission to intensive care units, and these conditions frequently exist in sequence or in tandem. Inflammatory responses to infections are reproduced by lipopolysaccharide (LPS) engaging Toll-like receptor 4 (TLR4). Apoptosis is a hallmark of lung injury in sepsis. This study was conducted to determine whether preexposure to LPS or hypoxia modulated the survival of pulmonary artery endothelial cells (PAECs). We also investigated the role TLR4 receptor expression plays in apoptosis due to these conditions. Bovine PAECs were cultured in hypoxic or normoxic environments and treated with …

Ex Vivo Diffusion Tensor Imaging Of Spinal Cord Injury In Rats Of Varying Degrees Of Severity, Michael Jirjis, Shekar N. Kurpad, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

The aim of this study was to characterize magnetic resonance diffusion tensor imaging (DTI) in proximal regions of the spinal cord following a thoracic spinal cord injury (SCI). Sprague–Dawley rats (n = 40) were administered a control, mild, moderate, or severe contusion injury at the T8 vertebral level. Six direction diffusion weighted images (DWIs) were collected ex vivo along the length of the spinal cord, with an echo/repetition time of 31.6 ms/14 sec and b = 500 sec/mm2. Diffusion metrics were correlated to hindlimb motor function. Significant differences were found for whole cord region of interest (ROI) drawings for fractional …

How Industry Benefits From Student Design, Jay R. Goldberg

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Outer Retinal Structure In Best Vitelliform Macular Dystrophy, David B. Kay, Megan E. Land, Robert F. Cooper, Adam M. Dubis, Pooja Godara, Alfredo Dubra, Joseph Carroll, Kimberly E. Stepien

Biomedical Engineering Faculty Research and Publications

Importance Demonstrating the utility of adaptive optics scanning light ophthalmoscopy (AOSLO) to assess outer retinal structure in Best vitelliform macular dystrophy (BVMD).

Objective To characterize outer retinal structure in BVMD using spectral-domain optical coherence tomography (SD-OCT) and AOSLO.

Design, Setting, and Participants Prospective, observational case series. Four symptomatic members of a family with BVMD with known BEST1 mutation were recruited at the Advanced Ocular Imaging Program research lab at the Medical College of Wisconsin Eye Institute, Milwaukee.

Intervention Thickness of 2 outer retinal layers corresponding to photoreceptor inner and outer segments was measured using SD-OCT. Photoreceptor mosaic AOSLO images within …

Few-View Single Photon Emission Computed Tomography (Spect) Reconstruction Based On A Blurred Piecewise Constant Object Model, Paul Arthur Wolf, Jakob S. Jørgensen, Taly Gilat Schmidt, Emil Y. Sidky

Biomedical Engineering Faculty Research and Publications

A sparsity-exploiting algorithm intended for few-view single photon emission computed tomography (SPECT) reconstruction is proposed and characterized. The algorithm models the object as piecewise constant subject to a blurring operation. To validate that the algorithm closely approximates the true object in the noiseless case, projection data were generated from an object assuming this model and using the system matrix. Monte Carlo simulations were performed to provide more realistic data of a phantom with varying smoothness across the field of view and a cardiac phantom. Reconstructions were performed across a sweep of two primary design parameters. The results demonstrate that the …

Evaluation Of Cast Creep Occurring During Simulated Clubfoot Correction, Tamara L. Cohen, Haluk Altiok, Mei Wang, Linda M. Mcgrady, Joseph Krzak, Adam Graf, Sergey Tarima, Peter A. Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

The Ponseti method is a widely accepted and highly successful conservative treatment of pediatric clubfoot involving weekly manipulations and cast applications. Qualitative assessments have indicated the potential success of the technique with cast materials other than standard plaster of Paris. However, guidelines for clubfoot correction based on the mechanical response of these materials have yet to be investigated. The current study sought to characterize and compare the ability of three standard cast materials to maintain the Ponseti-corrected foot position by evaluating cast creep response. A dynamic cast testing device, built to model clubfoot correction, was wrapped in plaster of Paris, …

Young's Modulus And Volume Porosity Relationships For Additive Manufacturing Applications, Stephen M. Heinrich, M. Barbara Silver-Thorn, John Anthony Choren

Biomedical Engineering Faculty Research and Publications

Recent advancements in additive manufacturing (or rapid prototyping) technologies allow the fabrication of end-use components with defined porous structures. For example, one area of particular interest is the potential to modify the flexibility (bending stiffness) of orthopedic implants through the use of engineered porosity (i.e., design and placement of pores) and subsequent fabrication of the implant using additive manufacturing processes. However, applications of engineered porosity require the ability to accurately predict mechanical properties from knowledge or characterization of the pore structure and the existence of robust equations characterizing the property–porosity relationships. As Young’s modulus can be altered by variations in …

Reducing Radiation Dose To The Female Breast During Ct Coronary Angiography: A Simulation Study Comparing Breast Shielding, Angular Tube Current Modulation, Reduced Kv, And Partial Angle Protocols Using An Unknown-Location Signal-Detectability Metric, Franco Rupcich, Andreu Badal, Lucretiu M. Popescu, Iacovos Kyprianou, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Purpose:

The authors compared the performance of five protocols intended to reduce dose to the breast during computed tomography (CT) coronary angiography scans using a model observer unknown-location signal-detectability metric.

Methods:

The authors simulated CT images of an anthropomorphic female thorax phantom for a 120 kV reference protocol and five “dose reduction” protocols intended to reduce dose to the breast: 120 kV partial angle (posteriorly centered), 120 kV tube-current modulated (TCM), 120 kV with shielded breasts, 80 kV, and 80 kV partial angle (posteriorly centered). Two image quality tasks were investigated: the detection and localization of 4-mm, 3.25 mg/ml and …

In Vivo Imaging Of Human Retinal Microvasculature Using Adaptive Optics Scanning Light Ophthalmoscope Fluorescein Angiography, Alexander Pinhas, Michael Dubow, Nishit Shah, Toco Y.P. Chui, Drew Scoles, Yusufu N. Sulai, Rishard Weitz, Joseph B. Walsh, Joseph Carroll, Alfredo Dubra, Richard B. Rosen

Biomedical Engineering Faculty Research and Publications

The adaptive optics scanning light ophthalmoscope (AOSLO) allows visualization of microscopic structures of the human retina in vivo. In this work, we demonstrate its application in combination with oral and intravenous (IV) fluorescein angiography (FA) to the in vivo visualization of the human retinal microvasculature. Ten healthy subjects ages 20 to 38 years were imaged using oral (7 and/or 20 mg/kg) and/or IV (500 mg) fluorescein. In agreement with current literature, there were no adverse effects among the patients receiving oral fluorescein while one patient receiving IV fluorescein experienced some nausea and heaving. We determined that all retinal capillary …

Hip Proprioceptors Preferentially Modulate Reflexes Of The Leg In Human Spinal Cord Injury, Tanya Onushko, Allison S. Hyngstrom, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

Stretch-sensitive afferent feedback from hip muscles has been shown to trigger long-lasting, multijoint reflex responses in people with chronic spinal cord injury (SCI). These reflexes could have important implications for control of leg movements during functional activities, such as walking. Because the control of leg movement relies on reflex regulation at all joints of the limb, we sought to determine whether stretch of hip muscles modulates reflex activity at the knee and ankle and, conversely, whether knee and ankle stretch afferents affect hip-triggered reflexes. A custom-built servomotor apparatus was used to stretch the hip muscles in nine chronic SCI subjects …

Optical Imaging Of Lipopolysaccharide-Induced Oxidative Stress In Acute Lung Injury From Hyperoxia And Sepsis, Reyhaneh Sepehr, Said H. Audi, Sepideh Maleki, Kevin Staniszewski, Annie L. Eis, Girija G. Konduri, Mahsa Ranji

Biomedical Engineering Faculty Research and Publications

Reactive oxygen species (ROS) have been implicated in the pathogenesis of many acute and chronic pulmonary disorders such as acute lung injury (ALI) in adults and bronchopulmonary dysplasia (BPD) in premature infants. Bacterial infection and oxygen toxicity, which result in pulmonary vascular endothelial injury, contribute to impaired vascular growth and alveolar simplification seen in the lungs of premature infants with BPD. Hyperoxia induces ALI, reduces cell proliferation, causes DNA damage and promotes cell death by causing mitochondrial dysfunction. The objective of this study was to use an optical imaging technique to evaluate the variations in fluorescence intensities of the auto-fluorescent …

Extra-Matrix Mg2+ Limits Ca2+ Uptake And Modulates Ca2+ Uptake-Independent Respiration And Redox State In Cardiac Isolated Mitochondria, Age D. Boelens, Ranjan K. Pradhan, Christoph A. Blomeyer, Amadou K.S. Camara, Ranjan K. Dash, David F. Stowe

Biomedical Engineering Faculty Research and Publications

Cardiac mitochondrial matrix (m) free Ca²⁺ ([Ca²⁺]_m) increases primarily by Ca²⁺ uptake through the Ca²⁺ uniporter (CU). Ca²⁺ uptake via the CU is attenuated by extra-matrix (e) Mg²⁺ ([Mg²⁺]_e). How [Ca²⁺]_m is dynamically modulated by interacting physiological levels of [Ca²⁺]_e and [Mg²⁺]_e and how this interaction alters bioenergetics are not well understood. We postulated that as [Mg²⁺]_e modulates Ca²⁺ uptake via the CU, it also alters bioenergetics in a matrix Ca²⁺–induced and …

North American Consortium On Rehabilitation Engineering And Technology For The Individual (Nareti), M. Barbara Silver-Thorn Phd, Karla Bustamante

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Surface Fluorescence Studies Of Tissue Mitochondrial Redox State In Isolated Perfused Rat Lungs, Kevin Staniszewski, Said H. Audi, Reyhaneh Sepehr, Elizabeth R. Jacobs, Mahsa Ranji

Biomedical Engineering Faculty Research and Publications

We designed a fiber-optic-based optoelectronic fluorometer to measure emitted fluorescence from the auto-fluorescent electron carriers NADH and FAD of the mitochondrial electron transport chain (ETC). The ratio of NADH to FAD is called the redox ratio (RR = NADH/FAD) and is an indicator of the oxidoreductive state of tissue. We evaluated the fluorometer by measuring the fluorescence intensities of NADH and FAD at the surface of isolated, perfused rat lungs. Alterations of lung mitochondrial metabolic state were achieved by the addition of rotenone (complex I inhibitor), potassium cyanide (KCN, complex IV inhibitor) and/or pentachlorophenol (PCP, uncoupler) into the perfusate recirculating …

Separation Of Visual And Motor Workspaces During Targeted Reaching Results In Limited Generalization Of Visuomotor Adaptation, Yuming Lei, Michelle J. Johnson, Jinsung Wang

Biomedical Engineering Faculty Research and Publications

Separating visual and proprioceptive information in terms of workspace locations during reaching movement has been shown to disturb transfer of visuomotor adaptation across the arms. Here, we investigated whether separating visual and motor workspaces would also disturb generalization of visuomotor adaptation across movement conditions within the same arm. Subjects were divided into four experimental groups (plus three control groups). The first two groups adapted to a visual rotation under a “dissociation” condition in which the targets for reaching movement were presented in midline while their arm performed reaching movement laterally. Following that, they were tested in an “association” condition in …

Brief Report: Visuo-Spatial Guidance Of Movement During Gesture Imitation And Mirror Drawing In Children With Autism Spectrum Disorders, Nicole M.G. Salowitz, Petra Eccarius, Audrey Meyer Carson, Kirsten A. Schohl, Sheryl Jayne Stevens, Amy Vaughan Van Hecke, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Thirteen autistic and 14 typically developing children (controls) imitated hand/arm gestures and performed mirror drawing; both tasks assessed ability to reorganize the relationship between spatial goals and the motor commands needed to acquire them. During imitation, children with autism were less accurate than controls in replicating hand shape, hand orientation, and number of constituent limb movements. During shape tracing, children with autism performed accurately with direct visual feedback, but when viewing their hand in a mirror, some children with autism generated fewer errors than controls whereas others performed much worse. Large mirror drawing errors correlated with hand orientation and hand …