Biomedical Engineering and Bioengineering Commons^™

High-Intensity Variable Stepping Training In Patients With Motor Incomplete Spinal Cord Injury: A Case Series, Carey L. Holleran, Patrick W. Hennessey, Abigail L. Leddy, Gordhan B. Mahtani, Gabrielle Brazg, Brian D. Schmit, T. George Hornby

Biomedical Engineering Faculty Research and Publications

Background and Purpose: Previous data suggest that large amounts of high-intensity stepping training in variable contexts (tasks and environments) may improve locomotor function, aerobic capacity, and treadmill gait kinematics in individuals poststroke. Whether similar training strategies are tolerated and efficacious for patients with other acute-onset neurological diagnoses, such as motor incomplete spinal cord injury (iSCI), is unknown. Individuals with iSCI potentially have greater bilateral impairments. This case series evaluated the feasibility and preliminary short- and long-term efficacy of highintensity variable stepping practice in ambulatory participants for more than 1 year post-iSCI.

Case Series Description: Four participants with iSCI (neurological levels …

Immersive Visualization In Biomedical Computational Fluid Dynamics And Didactic Teaching And Learning, John Thomas Venn

Master's Theses (2009 -)

Virtual reality (VR) can stimulate active learning, critical thinking, decision making and improved performance. It requires a medium to show virtual content, which is called a virtual environment (VE). The MARquette Visualization Lab (MARVL) is an example of a VE. Robust processes and workflows that allow for the creation of content for use within MARVL further increases the userbase for this valuable resource. A workflow was created to display biomedical computational fluid dynamics (CFD) and complementary data in a wide range of VE’s. This allows a researcher to study the simulation in its natural three-dimensional (3D) morphology. In addition, it …

Investigation Of Reactive Oxygen Species Production In The Rat Lung Using Optical Imaging, Nina Friedly

Master's Theses (2009 -)

Oxidative stress, the imbalance between production of oxidants or reactive oxygen species (ROS) and antioxidant activity, plays a key role in the pathogenesis of acute and chronic lung diseases. The objective of this thesis was to develop a robust protocol for measuring the rate of H2O2 production in isolated perfused rat lungs and to determine the cellular sources of that rate using Amplex Red (AR). For a given lung, AR (25 mM) along with horseradish peroxidase (5 U/ml) and ascorbate oxidase (1U/ml) were added to a perfusate reservoir that was recirculated through the lungs and sampled at 5 minute intervals …

Investigation Of The Effects Of Prosthetic Knee Condition On Novice Transfemoral Amputee Runners, Natalie Nelson

Master's Theses (2009 -)

Some unilateral transfemoral amputees (TFAs) run in a prosthesis with an articulating prosthetic knee, others choose to run without a knee (prosthetic socket and foot are linked via a straight, non-articulating pylon) to increase stability. Research regarding unilateral TFA running with an unlocked versus locked prosthetic knee (approximately equivalent to the no-knee condition) with respect to energy cost and temporal metrics is limited; no studies have investigated the impact of knee condition on kinematic metrics. The purpose of this study was to investigate whether the prosthetic knee of a running-specific prosthesis (RSP) should be unlocked or locked for unilateral TFAs …

Effect Of Sensory Attenuation On Cortical Movement-Related Oscillations, Joseph J. Lee, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

This study examined the impact of induced sensory deficits on cortical, movement-related oscillations measured using electroencephalography (EEG). We hypothesized that EEG patterns in healthy subjects with induced sensory reduction would be comparable to EEG found after chronic loss of sensory feedback. EEG signals from 64 scalp locations were measured from 10 healthy subjects. Participants dorsiflexed their ankle after prolonged vibration of the tibialis anterior (TA). Beta band time frequency decompositions were calculated using wavelets and compared across conditions. Changes in patterns of movement-related brain activity were observed following attenuation of sensory feedback. A significant decrease in beta power of event-related …

Evaluation Of Motion Artifact Metrics For Coronary Ct Angiography, Hongfeng Ma, Eric Gros, Aniko Szabo, Scott G. Baginski, Zachary R. Laste, Naveen M. Kulkarni, Darin Okerlund, Tal Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Purpose

This study quantified the performance of coronary artery motion artifact metrics relative to human observer ratings. Motion artifact metrics have been used as part of motion correction and best‐phase selection algorithms for Coronary Computed Tomography Angiography (CCTA). However, the lack of ground truth makes it difficult to validate how well the metrics quantify the level of motion artifact. This study investigated five motion artifact metrics, including two novel metrics, using a dynamic phantom, clinical CCTA images, and an observer study that provided ground‐truth motion artifact scores from a series of pairwise comparisons.

Method

Five motion artifact metrics were calculated …

Hyperoxia Causes Mitochondrial Fragmentation In Pulmonary Endothelial Cells By Increasing Expression Of Pro-Fission Proteins, Cui Ma, Andreas M. Beyer, Matthew J. Durand, Anne V. Clough, Daling Zhu, Laura Norwood Toro, Maia Terashvili, Johnathan D. Ebben, R. Blake Hill, Said H. Audi, Meetha Medhora, Elizabeth R. Jacobs

Biomedical Engineering Faculty Research and Publications

Objective—We explored mechanisms that alter mitochondrial structure and function in pulmonary endothelial cells (PEC) function after hyperoxia.

Approach and Results—Mitochondrial structures of PECs exposed to hyperoxia or normoxia were visualized and mitochondrial fragmentation quantified. Expression of pro-fission or fusion proteins or autophagy-related proteins were assessed by Western blot. Mitochondrial oxidative state was determined using mito-roGFP. Tetramethylrhodamine methyl ester estimated mitochondrial polarization in treatment groups. The role of mitochondrially derived reactive oxygen species in mt-fragmentation was investigated with mito-TEMPOL and mitochondrial DNA (mtDNA) damage studied by using ENDO III (mt-tat-endonuclease III), a protein that repairs mDNA damage. Drp-1 (dynamin-related …

Motor Output Variability Impairs Driving Ability In Older Adults: Reply To Stinchcombe, Dickerson, Weaver, And Bedard, Evangelos A. Christou, Basma Yacoubi, Changki Kim, Hwasil Moon, Tanya Onushko, Neha Lodha

Biomedical Engineering Faculty Research and Publications

Driving is a complex skill, as indicated by Stinchcombe and colleagues in their letter. It requires the integration of sensory inputs, cognitive processing, and motor execution. Although our title is broad, we clearly indicate that our findings only address a single component of driving, namely reactive driving. We also indicate that these findings are based on a simulated task and recommend that future studies should examine the contribution of motor output variability to on-road driving performance (see Considerations in the Discussion section). Thus, we share the consideration of Stinchcombe and colleagues that the current results only address a small portion …

Optimizing Within-Subject Experimental Designs For Jica Of Multi-Channel Erp And Fmri, Jain Mangalathu-Arumana, Einat Liebenthal, Scott A. Beardsley

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Inverse Kinematic Assessment Of Rehabilitative Therapy In Children Using Orthotics, Michael P. Murphy, Jacob R. Rammer, Kaleb L. Vinohout, Meghan R. Caballero, Christy M. Cornwell, Jessica M. Fritz, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Pathologic movement patterns are characterized by abnormal kinematics that alter how muscles support the body during walking. Individual muscles are often the target of interventions with physical therapy and surgery alike, yet the tools to assess individual muscles clinically remain limited. The aim of this study is to assess OpenSim as a clinical tool for individualized rehabilitative evaluation of children using orthotics. This anatomic and kinematic modeling study was focused on pre- and post-treatment assessment of gait characteristics in fourteen children using orthotic devices. A range of four to twelve acceptable gait capture trials was collected for each child before …

Opioids Delay Healing Of Spinal Fusion: A Rabbit Posterolateral Lumbar Fusion Model, Nikhil Jain, Khaled Himed, Jeffrey M. Toth, Karen C. Briley, Frank M. Phillips, Safdar N. Khan

Biomedical Engineering Faculty Research and Publications

Background Context

Opioid use is prevalent in the management of pre- and postoperative pain in patients undergoing spinal fusion. There is evidence that opioids downregulate osteoblasts in vitro, and a previous study found that morphine delays the maturation and remodeling of callus in a rat femur fracture model. However, the effect of opioids on healing of spinal fusion has not been investigated before. Isolating the effect of opioid exposure in humans would be limited by the numerous confounding factors that affect fusion healing. Therefore, we have used a well-established rabbit model to study the process of spinal fusion healing that …

A Student-Centered Learning Approach To Design For Manufacturability: Meeting The Needs Of An Often- Forgotten Customer, Jay R. Goldberg, David Rank

Biomedical Engineering Faculty Research and Publications

A hands-on learning module was implemented at Marquette University in 2012 to teach biomedical engineering students about basic manufacturing processes, lean manufacturing principles, and design for manufacturability. It incorporates active and student-centered learning as part of in-class assembly line simulations. Since then, it has evolved from three class periods to five. The module begins with two classroom presentations on manufacturing operations and electronics design, assembly, and testing. Students then participate in an in-class assembly line simulation exercise where they build and test an actual product per written work instructions. They reflect on this experience and suggest design and process changes …

Use Of A Dynamic Balance System To Quantify Postural Steadiness And Stability Of Individuals With Lower-Limb Amputation: A Pilot Study, M. Barbara Silver-Thorn Phd, Joel Kempfer, Alyssa J. Schnorenberg, Brooke Slavens

Biomedical Engineering Faculty Research and Publications

Introduction Despite rehabilitation and gait training, the gait of individuals with lower-limb amputation is often asymmetric and falls and/or fear of falling are common. Clinical assessments of balance and stability include the Berg BalanceScale and the Dynamic Gait Index. Biomechanical assessments, conducted largely in research laboratories, are more objective, quantitative, and may provide greater resolution. These biomechanical measures include postural sway during both unilateral and bilateral standing tasks and the dynamic postural response to applied or volitional perturbations. The objective of this study was to investigate the utility of a dynamic balance system, a relatively new clinical tool incorporating dual …

Real Time Evaluation Of Tissue Optical Properties During Thermal Ablation Of Ex Vivo Liver Tissues, Vivek K. Nagarajan, Venkateswara R. Gogineni, Sarah B. White, Bing Yu

Biomedical Engineering Faculty Research and Publications

Complete ablation of liver tumors is vital for minimizing the risk of local tumor recurrence. Accurately identifying the hallmarks of tissue necrosis during thermal ablative therapies may significantly increase the efficacy of ablation, while minimizing unnecessary damage to the surrounding normal tissues or critical structures. Light propagation in biological tissues is sensitive to the tissue microstructure and chromophore concentrations. In our previous studies, we found that the wavelength (λ) averaged liver tissue absorption coefficient μ_a and reduced scattering coefficient μ_s’ change significantly upon heating which may be used for assessment of tissue damage during thermal …

Optimizing Filter-Probe Diffusion Weighting In The Rat Spinal Cord For Human Translation, Matthew D. Budde, Nathan P. Skinner, L. Tugan Muftuler, Brian D. Schmit, Shekar N. Kurpad

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Biomechanical Tolerance Of Whole Lumbar Spines In Straightened Posture Subjected To Axial Acceleration, Brian D. Stemper, Sajal Chirvi, Ninh Doan, Jamie L. Baisden, Dennis J. Maiman, William H. Curry, Narayan Yoganandan, Frank A. Pintar, Glenn Paskoff, Barry S. Shender

Biomedical Engineering Faculty Research and Publications

Quantification of biomechanical tolerance is necessary for injury prediction and protection of vehicular occupants. This study experimentally quantified lumbar spine axial tolerance during accelerative environments simulating a variety of military and civilian scenarios. Intact human lumbar spines (T12‐L5) were dynamically loaded using a custom‐built drop tower. Twenty‐three specimens were tested at sub‐failure and failure levels consisting of peak axial forces between 2.6 and 7.9 kN and corresponding peak accelerations between 7 and 57 g. Military aircraft ejection and helicopter crashes fall within these high axial acceleration ranges. Testing was stopped following injury detection. Both peak force and acceleration were significant …

The Temporal Expression Of Adipokines During Spinal Fusion, Sohrab Virk, Alicia L. Bertone, Hayam Hamaz Hussein, Jeffrey M. Toth, Mari Kaido, Safdar Khan

Biomedical Engineering Faculty Research and Publications

Background Context

Adipokines are secreted by white adipose tissue and have been associated with fracture healing. Our goal was to report the temporal expression of adipokines during spinal fusion in an established rabbit model.

Purpose

Our goal was to report the temporal expression of adipokines during spinal fusion in an established rabbit model.

Study Design

The study design included a laboratory animal model.

Methods

New Zealand white rabbits were assigned to either sham surgery (n=2), unilateral posterior spinal fusion (n=14), or bilateral posterior spinal fusion (n=14). Rabbits were euthanized 1–6 and 10 weeks out from surgery. Fusion was evaluated by …

Macroscopic Anisotropic Bone Material Properties In Children With Severe Osteogenesis Imperfecta, Carolyne Albert, John Jameson, Sergey Tarima, Peter Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Children with severe osteogenesis imperfecta(OI) typically experience numerous fractures and progressive skeletal deformities over their lifetime. Recent studies proposed finite element models to assess fracture risk and guide clinicians in determining appropriate intervention in children with OI, but lack of appropriate material property inputs remains a challenge. This study aimed to characterize macroscopic anisotropic cortical bone material properties and investigate relationships with bone density measures in children with severe OI. Specimens were obtained from tibial or femoral shafts of nine children with severe OI and five controls. The specimens were cut into beams, characterized in bending, and imaged by synchrotron …

Sagittal Subtalar And Talocrural Joint Assessment During Ambulation With Controlled Ankle Movement (Cam) Boots, Ben Mchenry, Emily L. Exten, Janelle A. Cross, Karen M. Kruger, Brian Law, Jessica M. Fritz, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background: The purpose of the current study was to determine sagittal plane talocrural and subtalar kinematic differences between barefoot and controlled ankle movement (CAM) boot walking. This study used fluoroscopic images to determine talar motion relative to tibia and calcaneal motion relative to talus.

Methods: Fourteen male subjects (mean age 24.1 ± 3.5 years) screened for normal gait were tested. A fluoroscopy unit was used to collect images at 200 Hz during stance. Sagittal motion of the talocrural and subtalar joints were analyzed barefoot and within short and tall CAM boots.

Results: Barefoot talocrural mean maximum plantar and dorsiflexion were …

Robotic Resistance Treadmill Training Improves Locomotor Function In Children With Cerebral Palsy: A Randomized Controlled Pilot Study, Ming Wu, Janis Kim, Deborah J. Gaebler-Spira, Brian D. Schmit, Pooja Arora

Biomedical Engineering Faculty Research and Publications

Objective

To determine whether applying controlled resistance forces to the legs during the swing phase of gait may improve the efficacy of treadmill training as compared with applying controlled assistance forces in children with cerebral palsy (CP).

Design

Randomized controlled study.

Setting

Research unit of a rehabilitation hospital.

Participants

Children with spastic CP (N=23; mean age, 10.6y; range, 6–14y; Gross Motor Function Classification System levels, I–IV).

Interventions

Participants were randomly assigned to receive controlled assistance (n=11) or resistance (n=12) loads applied to the legs at the ankle. Participants underwent robotic treadmill training 3 times a week for 6 weeks (18 …

Protection By Inhaled Hydrogen Therapy In A Rat Model Of Acute Lung Injury Can Be Tracked In Vivo Using Molecular Imaging, Said H. Audi, Elizabeth R. Jacobs, Xiao Zhang, Amadou K.S. Camara, Ming Zhao, Meetha M. Medhora, Benjamin Michael Rizzo, Anne V. Clough

Biomedical Engineering Faculty Research and Publications

Inhaled hydrogen gas (H₂) provides protection in rat models of human acute lung injury (ALI). We previously reported that biomarker imaging can detect oxidative stress and endothelial cell death in vivo in a rat model of ALI. Our objective was to evaluate the ability of ^99mTc-hexamethylpropyleneamineoxime (HMPAO) and ^99mTc-duramycin to track the effectiveness of H₂ therapy in vivo in the hyperoxia rat model of ALI. Rats were exposed to room air (normoxia), 98% O₂ + 2% N₂ (hyperoxia) or 98% O₂ + 2% H₂ (hyperoxia+H₂) for up to 60 …

Muscle Coordination Contributes To Function After Stroke; Proprioception Contributes To Control Of Posture, Movement, Maria Bengtson

Dissertations (1934 -)

More than half of stroke survivors experience persistent upper extremity motor impairments that can negatively impact quality of life and independence. Effective use of the upper extremity requires coordination of agonist/antagonist muscle pairs, as well as coordination of multiple control actions for stabilizing and moving the arm. In this dissertation, I present three studies in which I recorded isometric torque production, single joint movement and stabilization, and clinical measures of function and impairments after stroke to evaluate the extent to which changes in coordination of agonist/antagonist muscles and of sequential control actions contribute to deficits after stroke. In Aim 1, …

Motion Artifact Evaluation Of Coronary Ct Angiography Images, Hongfeng Ma

Dissertations (1934 -)

The objective of this dissertation was to develop and validate an automated algorithm to quantify motion artifact level on coronary CT angiography (CCTA) images. Unlike existing motion artifact reduction techniques that evaluate the relative level of motion artifacts within one exam, this dissertation aims to quantify the absolute level of motion artifacts across exams from varying patients. The ability to quantify absolute motion artifact level enables several potential applications, for example, assessing and comparing two motion artifact reduction techniques. This dissertation includes three specific aims. Aim 1 investigated the absolute motion artifact quantification effectiveness of six motion artifact metrics using …

Collapsible Silicone Tubes: An In Vitro Model For Tracheal Traction, Kevin D. Garman

Master's Theses (2009 -)

Obstructive sleep apnea (OSA) is characterized by recurrent episodes of airway collapse and airflow limitation during sleep. Fragmented sleep and reductions in blood oxygen saturation lead to several comorbidities, including hypertension, cardiovascular disease, and cerebrovascular disease. Longitudinal forces (tracheal traction) acting on the soft tissues surrounding the upper airway have been proposed to play a significant role in stabilizing the airway and preventing collapse. However, the relative contribution of longitudinal forces as compared to other factors that affect airway stability (airway geometry, tissue properties, muscle activity) remains unclear. This in-vitro study aimed to investigate to what extent longitudinal forces can …

Effects Of Random Oscillations On Balance Control In Healthy Young Adults, Jacob Van Dehy

Master's Theses (2009 -)

In human walking, balance control is managed through proactive changes in spatio-temporal parameters of stepping [1]. It has been suggested that continuous disruptions to healthy young adult balance cause greater changes to overall variability of these parameters than a shift in the mean stepping parameters [2]. This suggests that walking may be occurring in a more reactive manner, modulating to maintain balance without increasing the mean significantly. Work using continuous oscillations to treadmill walking suggest there is an interplay between the predictability of a signal used to disrupt subject balance and the degree to which compensation occurs [3]. To determine …

Elucidating The Mechanical, Structural, Functional, And Molecular Mechanisms Involved In Irreversible Vascular Changes In Aortic Coarctation, Brandon Wegter

Master's Theses (2009 -)

Coarctation of the aorta (CoA) is a constriction of the thoracic aorta and is one of the most common congenital cardiovascular defects. Treatment by surgical correction has saved the lives of thousands of children, but many still have a reduced lifespan due to hypertension. Previous results using our novel rabbit model showed that the current treatment guideline of a 20 mmHg blood pressure gradient (BPG) induces irreversible vascular changes, which persisted despite correction. Preliminary data of the downregulation of natriuretic peptide receptor C (NPR-C) in proximal aortic tissue of human patients with CoA serves as the possible underlying mechanism for …

Treating A 20 Mm Hg Gradient Alleviates Myocardial Hypertrophy In Experimental Aortic Coarctation, David C. Wendell, Ingeborg Friehs, Margaret M. Samyn, Leanne Harmann, John F. Ladisa

Biomedical Engineering Faculty Research and Publications

Background

Children with coarctation of the aorta (CoA) can have a hyperdynamic and remodeled left ventricle (LV) from increased afterload. Literature from an experimental model suggests the putative 20 mm Hg blood pressure gradient (BPG) treatment guideline frequently implemented in CoA studies may permit irreversible vascular changes. LV remodeling from pressure overload has been studied, but data are limited following correction and using a clinically representative BPG.

Materials and methods

Rabbits underwent CoA at 10 weeks to induce a 20 mm Hg BPG using permanent or dissolvable suture thereby replicating untreated and corrected CoA, respectively. Cardiac function was evaluated at …

A Spectral Ct Method To Directly Estimate Basis Material Maps From Experimental Photon-Counting Data, Tal Gilat Schmidt, Rina Foygel Barber, Emil Y. Sidky

Biomedical Engineering Faculty Research and Publications

The proposed spectral CT method solves the constrained one-step spectral CT reconstruction (cOSSCIR) optimization problem to estimate basis material maps while modeling the nonlinear X-ray detection process and enforcing convex constraints on the basis map images. In order to apply the optimization-based reconstruction approach to experimental data, the presented method empirically estimates the effective energy-window spectra using a calibration procedure. The amplitudes of the estimated spectra were further optimized as part of the reconstruction process to reduce ring artifacts. A validation approach was developed to select constraint parameters. The proposed spectral CT method was evaluated through simulations and experiments with …

A Long-Term Follow-Up Of Young Adults With Idiopathic Clubfoot: Does Foot Morphology Relate To Pain?, Adam Graf, Ken N. Kuo, Nikhil T. Kurapati, Joseph J. Krzak, Sahar Hassani, Angela Caudill, Ann Flanagan, Gerald F. Harris, Peter A. Smith

Biomedical Engineering Faculty Research and Publications

Background:

Individuals with clubfoot, treated in infancy with either the Ponseti method or comprehensive clubfoot release, often encounter pain as adults. Multiple studies have characterized residual deformity after Ponseti or surgical correction using physical exam, radiographs and pedobarography; however, the relationship between residual foot deformity and pain is not well defined. The purpose of the current study was 2-fold: (1) to evaluate the relationship between foot morphology and pain for young adults treated as infants for idiopathic clubfoot and (2) to describe and compare pedobarographic measures and outcome measures of pain and morphology among surgically treated, Ponseti treated, and typically …

Open Source Software For Automatic Detection Of Cone Photoreceptors In Adaptive Optics Ophthalmoscopy Using Convolutional Neural Networks, David Cunefare, Leyuan Fang, Robert F. Cooper, Alfredo Dubra, Joseph Carroll, Sina Farsiu

Biomedical Engineering Faculty Research and Publications

Imaging with an adaptive optics scanning light ophthalmoscope (AOSLO) enables direct visualization of the cone photoreceptor mosaic in the living human retina. Quantitative analysis of AOSLO images typically requires manual grading, which is time consuming, and subjective; thus, automated algorithms are highly desirable. Previously developed automated methods are often reliant on ad hoc rules that may not be transferable between different imaging modalities or retinal locations. In this work, we present a convolutional neural network (CNN) based method for cone detection that learns features of interest directly from training data. This cone-identifying algorithm was trained and validated on separate data …