Biomedical Engineering and Bioengineering Commons^™

Critical Changes In Cortical Neuronal Interactions In Anesthetized And Awake Rats, Anthony G. Hudetz, Jeannette A. Vizuete, Siveshigan Pillay, Kristina M. Ropella

Biomedical Engineering Faculty Research and Publications

Background: Neuronal interactions are fundamental for information processing, cognition, and consciousness. Anesthetics reduce spontaneous cortical activity; however, neuronal reactivity to sensory stimuli is often preserved or augmented. How sensory stimulus–related neuronal interactions change under anesthesia has not been elucidated. In this study, the authors investigated the visual stimulus–related cortical neuronal interactions during stepwise emergence from desflurane anesthesia.

Methods: Parallel spike trains were recorded with 64-contact extracellular microelectrode arrays from the primary visual cortex of chronically instrumented, unrestrained rats (N = 6) at 8, 6, 4, and 2% desflurane anesthesia and wakefulness. Light flashes were delivered to the retina …

A Novel Fmri Paradigm Suggests That Pedaling-Related Brain Activation Is Altered After Stroke, Nutta-On Promjunyakul, Brian D. Schmit, Sheila M. Schindler-Ivens

Physical Therapy Faculty Research and Publications

The purpose of this study was to examine the feasibility of using functional magnetic resonance imaging (fMRI) to measure pedaling-related brain activation in individuals with stroke and age-matched controls. We also sought to identify stroke-related changes in brain activation associated with pedaling. Fourteen stroke and 12 control subjects were asked to pedal a custom, MRI-compatible device during fMRI. Subjects also performed lower limb tapping to localize brain regions involved in lower limb movement. All stroke and control subjects were able to pedal while positioned for fMRI. Two control subjects were withdrawn due to claustrophobia, and one control data set was …

A Portable, Low-Cost Wheelchair Ergometer Design Based On A Mathematical Model Of Pediatric Wheelchair Dynamics, Jacob R. Rammer, Susan A. Riedel, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Evaluation and training of wheelchair propulsion improves efficiency and prevents orthopaedic injury in pediatric manual wheelchair users. Ergometers allow static propulsion and emulate typical conditions. Currently available ergometers have deficiencies that limit their use in motion analysis. A new ergometer is developed and evaluated based on a model of wheelchair inertial dynamics that eliminates these deficiencies. This makes integrated motion analysis of wheelchair propulsion in current community, home, and international outreach efforts possible.

Virtual Capstone Design Teams: Preparing For Global Innovation (Journal Article), Jay R. Goldberg, Susannah Howe

Biomedical Engineering Faculty Research and Publications

Global innovation requires collaboration between groups of people located in different parts of the world, and is a growing trend in industry. Virtual teams are often used to manage new product development projects. These teams are similar to traditional teams but are geographically separated and rely heavily on virtual methods of communication (email, Skype, teleconferencing, etc.) instead of regular face-to-face meetings. Experience working as a member of a virtual capstone design team can help prepare students for this growing trend. To begin preparing students for work on virtual teams in industry, we co-advised two virtual capstone design projects with students …

Recent Developments In Osteogenesis Imperfecta, Joseph L. Shaker, Carolyne Albert, Jessica M. Fritz, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Osteogenesis imperfecta (OI) is an uncommon genetic bone disease associated with brittle bones and fractures in children and adults. Although OI is most commonly associated with mutations of the genes for type I collagen, many other genes (some associated with type I collagen processing) have now been identified. The genetics of OI and advances in our understanding of the biomechanical properties of OI bone are reviewed in this article. Treatment includes physiotherapy, fall prevention, and sometimes orthopedic procedures. In this brief review, we will also discuss current understanding of pharmacologic therapies for treatment of OI.

Kinematic Foot Types In Youth With Equinovarus Secondary To Hemiplegia, Joseph Krzak, Daniel M. Corcos, Diane L. Damiano, Adam Graf, Donald Hedeker, Peter A. Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background

Elevated kinematic variability of the foot and ankle segments exists during gait among individuals with equinovarus secondary to hemiplegic cerebral palsy (CP). Clinicians have previously addressed such variability by developing classification schemes to identify subgroups of individuals based on their kinematics.

Objective

To identify kinematic subgroups among youth with equinovarus secondary to CP using 3-dimensional multi-segment foot and ankle kinematics during locomotion as inputs for principal component analysis (PCA), and K-means cluster analysis.

Methods

In a single assessment session, multi-segment foot and ankle kinematics using the Milwaukee Foot Model (MFM) were collected in 24 children/adolescents with equinovarus and …

Guest Editorial: The 2014 Capstone Design Conference, Steven Beyerlein, Jay R. Goldberg, Susannah Howe, Scott Palo, Renee Rogge, R. Keith Stanfill

Biomedical Engineering Faculty Research and Publications

The goal of the 2014 Capstone Design Conference held in Columbus, OH was to build upon the success of three previous conferences (2007 and 2010 in Boulder, CO, and 2012 in Champaign, IL) and expand the community of educators, students, and industry members engaged in discussing, analyzing, and improving capstone design education. Sessions at the 2014 Capstone Design Conference were designed for vibrant sharing of ideas and experiences across the capstone community via interactive panel sessions, poster session socials, and hands-on workshops. This editorial discusses conference planning, structure, and feedback. Technical papers that follow in this issue document scholarship surrounding …

Large-Scale Spatiotemporal Spike Patterning Consistent With Wave Propagation In Motor Cortex, Kazutaka Takahashi, Sanggyun Kim, Todd P. Coleman, Kevin A. Brown, Aaron J. Suminski, Matthew D. Best, Nicholas G. Hatsopoulos

Biomedical Engineering Faculty Research and Publications

Aggregate signals in cortex are known to be spatiotemporally organized as propagating waves across the cortical surface, but it remains unclear whether the same is true for spiking activity in individual neurons. Furthermore, the functional interactions between cortical neurons are well documented but their spatial arrangement on the cortical surface has been largely ignored. Here we use a functional network analysis to demonstrate that a subset of motor cortical neurons in non-human primates spatially coordinate their spiking activity in a manner that closely matches wave propagation measured in the beta oscillatory band of the local field potential. We also demonstrate …

In Vivo Detection Of Hyperoxia-Induced Pulmonary Endothelial Cell Death Using 99mTc-Duramycin, Said H. Audi, Elizabeth R. Jacobs, Ming Zhao, David L. Roerig, Steven T. Haworth, Anne V. Clough

Biomedical Engineering Faculty Research and Publications

Introduction

^99mTc-duramycin, DU, is a SPECT biomarker of tissue injury identifying cell death. The objective of this study is to investigate the potential of DU imaging to quantify capillary endothelial cell death in rat lung injury resulting from hyperoxia exposure as a model of acute lung injury.

Methods

Rats were exposed to room air (normoxic) or > 98% O₂ for 48 or 60 hours. DU was injected i.v. in anesthetized rats, scintigraphy images were acquired at steady-state, and lung DU uptake was quantified from the images. Post-mortem, the lungs were removed for histological studies. Sequential lung sections were immunostained …

Intention Tremor And Deficits Of Sensory Feedback Control In Multiple Sclerosis: A Pilot Study, Megan Heenan, Robert A. Scheidt, Douglas Woo, Scott A. Beardsley

Biomedical Engineering Faculty Research and Publications

Background

Intention tremor and dysmetria are leading causes of upper extremity disability in Multiple Sclerosis (MS). The development of effective therapies to reduce tremor and dysmetria is hampered by insufficient understanding of how the distributed, multi-focal lesions associated with MS impact sensorimotor control in the brain. Here we describe a systems-level approach to characterizing sensorimotor control and use this approach to examine how sensory and motor processes are differentially impacted by MS.

Methods

Eight subjects with MS and eight age- and gender-matched healthy control subjects performed visually-guided flexion/extension tasks about the elbow to characterize a sensory feedback control model that …

Reversible Blockade Of Complex I Or Inhibition Of Pkcβ Reduces Activation And Mitochondria Translocation Of P66Shc To Preserve Cardiac Function After Ischemia, Meiying Yang, David F. Stowe, Kenechukwu B. Udoh, James S. Heisner, Amadou K.S. Camara

Biomedical Engineering Faculty Research and Publications

Aim

Excess mitochondrial reactive oxygen species (mROS) play a vital role in cardiac ischemia reperfusion (IR) injury. P66^Shc, a splice variant of the ShcA adaptor protein family, enhances mROS production by oxidizing reduced cytochrome c to yield H₂O₂. Ablation of p66^Shc protects against IR injury, but it is unknown if and when p66^Shc is activated during cardiac ischemia and/or reperfusion and if attenuating complex I electron transfer or deactivating PKCβ alters p66^Shc activation during IR is associated with cardioprotection.

Methods

Isolated guinea pig hearts were perfused and subjected to increasing periods …

Characterization Of Bone Material Properties And Microstructure In Osteogenesis Imperfecta/Brittle Bone Disease, John Robert Jameson

Dissertations (1934 -)

Osteogenesis imperfecta (OI) is a genetic disorder primarily associated with mutations to type I collagen and resulting in mild to severe bone fragility. To date, there is very little data quantifying OI cortical bone mechanics. The purpose of this dissertation was to investigate bone microstructure, mineralization, and mechanical properties in adolescents with OI. Characterization studies were performed on small osteotomy specimens obtained from the extremities during routine corrective surgeries. Nanoindentation was used to examine the longitudinal elastic modulus and hardness at the material level for mild OI type I vs. severe OI type III. Both modulus and hardness were significantly …

Neuromodulation For Depression: Insights Gained From Neuroimaging And Computational Models, Yagna Pathak

Dissertations (1934 -)

Major depressive disorder (MDD) is a public health concern worldwide, affecting a sixth of the American population. Neuromodulation therapies have been employed to treat severe cases of treatment resistant depression. These procedures attempt to modulate activity in cortical regions that represent nodes in brain circuits believed to be involved in MDD. One challenge in neuromodulation trials has been the difficulty in quantifying outcome variability. We sought to understand the effects of neuromodulation therapies and their sources of variability while adding an objective perspective to assess clinical improvement in neuropsychiatric disorders such as depression. The goal of my dissertation was to …

A Subject-Specific Multiscale Model Of Transcranial Magnetic Stimulation, Brian Daniel Goodwin

Dissertations (1934 -)

Transcranial magnetic stimulation (TMS) is a neuromodulation technique used to treat a variety of neurological disorders. While many types of neuromodulation therapy are invasive, TMS is an attractive alternative because it is noninvasive and has a very strong safety record. However, clinical use of TMS has preceded a thorough scientific understanding: its mechanisms of action remain elusive, and the spatial extent of modulation is not well understood. We created a subject-specific, multiscale computational model to gain insights into the physiological response during motor cortex TMS. Specifically, we developed an approach that integrates three main components: 1) a high-resolution anatomical MR …

Kinematic Analysis Of The Glenohumeral Joint: A Comparison Of Post-Operative Rotator Cuff Repair Patients And Controls, Ryan Richard Inawat

Master's Theses (2009 -)

Rotator cuff (RC) repair is a standard surgical intervention used to alleviate pain and loss of function in the shoulder due to torn RC tendons, involving re-attachment of the tendon to the humerus. Quantitative evaluation of kinematics following RC repair is possible with video motion analysis techniques, yet is rarely performed. With the purpose of quantifying the effects of RC repair, a Vicon 524 (Oxford, UK) motion analysis system was used to investigate three-dimensional (3D) kinematics of the glenohumeral (GH) joint and thorax following supraspinatus repair. A validated, 18 marker, inverse dynamics model based on ISB standards was applied to …

Within-Socket Myoelectric Prediction Of Continuous Ankle Kinematics For Control Of A Powered Transtibial Prosthesis, Samuel Farmer, M. Barbara Silver-Thorn, Philip A. Voglewede, Scott A. Beardsley

Biomedical Engineering Faculty Research and Publications

Objective. Powered robotic prostheses create a need for natural-feeling user interfaces and robust control schemes. Here, we examined the ability of a nonlinear autoregressive model to continuously map the kinematics of a transtibial prosthesis and electromyographic (EMG) activity recorded within socket to the future estimates of the prosthetic ankle angle in three transtibial amputees. Approach. Model performance was examined across subjects during level treadmill ambulation as a function of the size of the EMG sampling window and the temporal 'prediction' interval between the EMG/kinematic input and the model's estimate of future ankle angle to characterize the trade-off between model error, …

Entrepreneurship In Capstone Design: Has The Pendulum Swung Too Far?, Jay R. Goldberg

Biomedical Engineering Faculty Research and Publications

The author supports entrepreneurial education for all interested students, but not at the expense of design education. He thinks we should develop business literacy among all of our students to prepare them for work in start-ups and established medical device companies, and provide opportunities for interested students to add entrepreneurial literacy to better prepare them to create new companies, either upon graduation or later in their careers. Capstone design courses should focus on helping students develop solid design skills and providing opportunities to apply the analytical tools learned in previous courses. Students should be encouraged, not required, to consider commercializing …

Reduced Diaphyseal Strength Associated With High Intracortical Vascular Porosity Within Long Bones Of Children With Osteogenesis Imperfecta, Carolyne Albert, John Jameson, Peter Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Osteogenesis imperfecta is a genetic disorder resulting in bone fragility. The mechanisms behind this fragility are not well understood. In addition to characteristic bone mass deficiencies, research suggests that bone material properties are compromised in individuals with this disorder. However, little data exists regarding bone properties beyond the microstructural scale in individuals with this disorder.

Specimens were obtained from long bone diaphyses of nine children with osteogenesis imperfecta during routine osteotomy procedures. Small rectangular beams, oriented longitudinally and transversely to the diaphyseal axis, were machined from these specimens and elastic modulus, yield strength, and maximum strength were measured in three-point …

Upper Extremity Biomechanics Of Children With Spinal Cord Injury During Wheelchair Mobility, Alyssa J. Schnorenberg, Brooke A. Slavens, Adam Graf, Joseph J. Krzak, Lawrence C. Vogel, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

While much work is being done evaluating the upper extremity joint dynamics of adult manual wheelchair propulsion, limited work has examined the pediatric population of manual wheelchair users. Our group used a custom pediatric biomechanical model to characterize the upper extremity joint dynamics of 12 children and adolescents with spinal cord injury (SCI) during wheelchair propulsion. Results show that loading appears to agree with that of adult manual wheelchair users, with the highest loading primarily seen at the glenohumeral joint. This is concerning due to the increased time of wheelchair use in the pediatric population and the impact of this …

Non-Common Path Aberration Correction In An Adaptive Optics Scanning Ophthalmoscope, Yusufu N. Sulai, Alfredo Dubra

Biomedical Engineering Faculty Research and Publications

The correction of non-common path aberrations (NCPAs) between the imaging and wavefront sensing channel in a confocal scanning adaptive optics ophthalmoscope is demonstrated. NCPA correction is achieved by maximizing an image sharpness metric while the confocal detection aperture is temporarily removed, effectively minimizing the monochromatic aberrations in the illumination path of the imaging channel. Comparison of NCPA estimated using zonal and modal orthogonal wavefront corrector bases provided wavefronts that differ by ~λ/20 in root-mean-squared (~λ/30 standard deviation). Sequential insertion of a cylindrical lens in the illumination and light collection paths of the imaging channel was used to compare image resolution …

The Reliability Of Parafoveal Cone Density Measurements, Benjamin S. Liu, Sergey Tarima, Alexis D. Visotcky, Alex Pechauer, Robert F. Cooper, Leah Landsem, Melissa A. Wilk, Pooja Godara, Vikram Makhijani, Yusufu N. Sulai, Najia Syed, Galen Yasumura, Anupam K. Garg, Mark E. Pennesi, Brandon J. Lujan, Alfredo Dubra, Jacque L. Duncan, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

Background Adaptive optics scanning light ophthalmoscopy (AOSLO) enables direct visualisation of the cone mosaic, with metrics such as cone density and cell spacing used to assess the integrity or health of the mosaic. Here we examined the interobserver and inter-instrument reliability of cone density measurements.

Methods For the interobserver reliability study, 30 subjects with no vision-limiting pathology were imaged. Three image sequences were acquired at a single parafoveal location and aligned to ensure that the three images were from the same retinal location. Ten observers used a semiautomated algorithm to identify the cones in each image, and this was repeated …

Relationship Between Foveal Cone Specialization And Pit Morphology In Albinism, Melissa A. Wilk, John T. Mcallister, Robert F. Cooper, Adam M. Dubis, Teresa N. Patitucci, Phyllis Summerfelt, Jennifer L. Anderson, Deborah M. Costakos, Thomas B. Connor Jr., William J. Wirostko, Pei-Wen Chiang, Alfredo Dubra, Christine A. Curcio, Murray H. Briliant, C. Gail Summers, Joseph Carroll, Jennifer L. Anderson

Biomedical Engineering Faculty Research and Publications

Purpose. Albinism is associated with disrupted foveal development, though intersubject variability is becoming appreciated. We sought to quantify this variability, and examine the relationship between foveal cone specialization and pit morphology in patients with a clinical diagnosis of albinism.

Methods. We recruited 32 subjects with a clinical diagnosis of albinism. DNA was obtained from 25 subjects, and known albinism genes were analyzed for mutations. Relative inner and outer segment (IS and OS) lengthening (fovea-to-perifovea ratio) was determined from manually segmented spectral domain-optical coherence tomography (SD-OCT) B-scans. Foveal pit morphology was quantified for eight subjects from macular SD-OCT volumes. Ten subjects …

Microscopic Inner Retinal Hyper-Reflective Phenotypes In Retinal And Neurologic Disease, Drew Scoles, Brian P. Higgins, Robert F. Cooper, Adam M. Dubis, Phyllis Summerfelt, David V. Weinberg, Judy E. Kim, Kimberly E. Stepien, Joseph Carroll, Alfredo Dubra

Biomedical Engineering Faculty Research and Publications

Purpose.

We surveyed inner retinal microscopic features in retinal and neurologic disease using a reflectance confocal adaptive optics scanning light ophthalmoscope (AOSLO).

Methods.

Inner retinal images from 101 subjects affected by one of 38 retinal or neurologic conditions and 11 subjects with no known eye disease were examined for the presence of hyper-reflective features other than vasculature, retinal nerve fiber layer, and foveal pit reflex. The hyper-reflective features in the AOSLO images were grouped based on size, location, and subjective texture. Clinical imaging, including optical coherence tomography (OCT), scanning laser ophthalmoscopy, and fundus photography was analyzed for comparison.

Results.

Seven …

Automated Selection Of The Optimal Cardiac Phase For Single-Beat Coronary Ct Angiography Reconstruction, Daniel Stassi

Master's Theses (2009 -)

This thesis investigates an automated algorithm for selecting the optimal cardiac phase for CCTA reconstruction. Reconstructing a low-motion cardiac phase improves coronary artery visualization in coronary CT angiography (CCTA) exams. Currently, standard end-systole and/or mid-diastole default phases are prescribed or alternatively, quiescent phases are determined by the user. As manual selection may be time-consuming and standard locations may be suboptimal due to patient variability, an automated method is investigated. An automated algorithm was developed to select the optimal phase based on quantitative image quality (IQ) metrics. For each reconstructed slice at each reconstructed phase, an image quality metric was calculated …

The Effects Of Organ-Based Tube Current Modulation On Radiation Dose And Image Quality In Computed Tomography Imaging, Diksha Gandhi

Master's Theses (2009 -)

The purpose of this thesis was to quantify dose and noise performance of organ-dose-based tube current modulation (ODM) through experimental studies with an anthropomorphic phantom and simulations with a voxelized phantom library. Tube current modulation is a dose reduction technique that modulates radiation dose in angular and/or slice directions based on patient attenuation. ODM technique proposed by GE Healthcare further reduces tube current for anterior source positions, without increasing current for posterior positions. Axial CT scans at 120 kV were performed on head and chest phantoms (Rando Alderson Research Laboratories, Stanford, CA) on an ODM-equipped scanner (Optima CT660, GE Healthcare, …

Effect Of Lowest Instrumented Vertebra On Trunk Mobility In Patients With Adolescent Idiopathic Scoliosis Undergoing A Posterior Spinal Fusion, Ubong I. Udoekwere, Joseph Krzak, Adam Graf, Sahar Hassani, Sergey Tarima, Mary Riordan, Peter F. Sturm, Kim W. Hammerberg, Purnendu Gupta, Alireza K. Anissipour, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Study Design

Prospective.

Objectives

The goal of this study was to evaluate the effect of posterior spinal fusion surgery terminating at different lowest instrumented vertebrae (LIV) on trunk mobility in individuals with adolescent idiopathic scoliosis (AIS).

Summary of Background Data

Posterior spinal fusion with instrumentation is the standard surgical technique employed in AIS for correcting spine deformities with Cobb angles exceeding 50°. Surgical correction of curve deformity reduces trunk mobility and range of motion. However, conflicting findings from previous studies investigating the impact of different LIV levels on the reduction in trunk mobility after surgery have been reported.

Methods

The …

Measuring Tumor Cycling Hypoxia And Angiogenesis Using A Side-Firing Fiber Optic Probe, Bing Yu, Amy Shah, Bingqing Wang, Narasimhan Rajaram, Quanli Wang, Nirmala Ramanujam, Gregory M. Palmer, Mark W. Dewhirst

Biomedical Engineering Faculty Research and Publications

Hypoxia and angiogenesis can significantly influence the efficacy of cancer therapy and the behavior of surviving tumor cells. There is a growing demand for technologies to measure tumor hypoxia and angiogenesis temporally in vivo to enable advances in drug development and optimization. This paper reports the use of frequency-domain photon migration with a side-firing probe to quantify tumor oxygenation and hemoglobin concentrations in nude rats bearing human head/neck tumors administered with carbogen gas, cycling hypoxic gas or just room air. Significant increase (with carbogen gas breathing) or decrease (with hypoxic gas breathing) in tumor oxygenation was observed. The trend in …

Looking For Your Next Disruptive Technology? Try Student Competitions, Jay R. Goldberg, Phil Weilerstein

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Learning Redundant Motor Tasks With And Without Overlapping Dimensions: Facilitation And Interference Effects, Rajiv Ranganathan, Jon A. Wieser, Kristine M. Mosier, Ferdinando A. Mussa-Ivaldi, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Prior learning of a motor skill creates motor memories that can facilitate or interfere with learning of new, but related, motor skills. One hypothesis of motor learning posits that for a sensorimotor task with redundant degrees of freedom, the nervous system learns the geometric structure of the task and improves performance by selectively operating within that task space. We tested this hypothesis by examining if transfer of learning between two tasks depends on shared dimensionality between their respective task spaces. Human participants wore a data glove and learned to manipulate a computer cursor by moving their fingers. Separate groups of …

In Vivo Imaging Of Human Cone Photoreceptor Inner Segments, Drew Scoles, Yusufu N. Sulai, Christopher S. Langlo, Gerald A. Fishman, Christine A. Curcio, Joseph Carroll, Alfredo Dubra

Biomedical Engineering Faculty Research and Publications

Purpose.

An often overlooked prerequisite to cone photoreceptor gene therapy development is residual photoreceptor structure that can be rescued. While advances in adaptive optics (AO) retinal imaging have recently enabled direct visualization of individual cone and rod photoreceptors in the living human retina, these techniques largely detect strongly directionally-backscattered (waveguided) light from normal intact photoreceptors. This represents a major limitation in using existing AO imaging to quantify structure of remnant cones in degenerating retina.

Methods.

Photoreceptor inner segment structure was assessed with a novel AO scanning light ophthalmoscopy (AOSLO) differential phase technique, that we termed nonconfocal split-detector, in two healthy …