Biomedical Engineering and Bioengineering Commons^™

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 …

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 …

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 …

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, …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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, …

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

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Electroencephalogram Coherence In Children With And Without Autism Spectrum Disorders: Decreased Interhemispheric Connectivity In Autism, Audrey Meyer Carson, Nicole M.G. Salowitz, Robert A. Scheidt, Bridget K. Dolan, Amy V. Van Hecke

Biomedical Engineering Faculty Research and Publications

Electroencephalogram coherence was measured in children with autism spectrum disorders (ASD) and control children at baseline and while watching videos of a familiar and unfamiliar person reading a story. Coherence was measured between the left and right hemispheres of the frontal, parietal, and temporal-parietal lobes (interhemispheric) and between the frontal and parietal lobes in each hemisphere (intrahemispheric). A data-reduction technique was employed to identify the frequency (alpha) that yielded significant differences in video conditions. Children with ASD displayed reduced coherence at the alpha frequency between the left and right temporal-parietal lobes in all conditions and reduced coherence at the alpha …

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 …

Robotic Resistance/Assistance Training Improves Locomotor Function In Individuals Poststroke: A Randomized Controlled Study, Ming Wu, Jill M. Landry, Janis Kim, Brian D. Schmit, Sheng-Che Yen, Jillian Macdonald

Biomedical Engineering Faculty Research and Publications

Objective

To determine whether providing a controlled resistance versus assistance to the paretic leg at the ankle during treadmill training will improve walking function in individuals poststroke.

Design

Repeated assessment of the same patients with parallel design and randomized controlled study between 2 groups.

Setting

Research units of rehabilitation hospitals.

Participants

Patients (N=30) with chronic stroke.

Intervention

Subjects were stratified based on self-selected walking speed and were randomly assigned to the resistance or assistance training group. For the resistance group, a controlled resistance load was applied to the paretic leg at the ankle to resist leg swing during treadmill walking. …

Feedback Regulation Of Limb Position Characterized Using Fmri, Aaron J. Suminski, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Faculty Internships For Capstone Design Instructors: Maintaining An Up-To-Date Capstone Design Course, Jay R. Goldberg

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Markerless Analysis Of Upper Extremity Kinematics During Standardized Pediatric Assessment, Jacob R. Rammer

Master's Theses (2009 -)

Children with hemiplegic cerebral palsy experience reduced motor performance in the affected upper extremity and are typically evaluated based on degree of functional impairment using activity-based assessments such as the Shriners Hospitals for Children Upper Extremity Evaluation (SHUEE), a validated clinical measure, to describe performance prior to and following rehabilitative or surgical interventions. Evaluations rely on subjective therapist scoring techniques and lack sensitivity to detect change. Objective clinical motion analysis systems are an available but time-consuming and cost-intensive alternative, requiring uncomfortable application of markers to the patient. There is currently no available markerless, low-cost system that quantitatively assesses upper extremity …

Computational Evaluation Of Shear Stress And Restenosis In Stented Coronary Arteries Using Optical Coherence Tomography, Joshua K. Hughey

Master's Theses (2009 -)

The cause of coronary artery neointimal thickness (NT) leading to restenosis in ~10% of drug-eluting stents (DES) is unknown, but adverse wall shear stress (WSS) may contribute. Prior studies comparing WSS to restenosis for first generation DES yielded conflicting results, and cited different mechanisms of action for DES agents. Studies to date have not accounted for stent geometry, which dictates local WSS patterns influencing drug concentration. The objective of this investigation was to evaluate current generation stent platforms via their WSS patterns and their respective impact on NT. We prospectively enrolled 19 patients, who were randomized to thin-strut (81μm) 2-link …

Quantification Of Local Hemodynamic Alterations Caused By Virtual Implantation Of Three Commercially Available Stents For The Treatment Of Aortic Coarctation, Sung Kwon, Jeffrey A. Feinstein, Ronak Jashwant Dholakia, John F. Ladisa

Biomedical Engineering Faculty Research and Publications

Patients with coarctation of the aorta (CoA) are prone to morbidity including atherosclerotic plaque that has been shown to correlate with altered wall shear stress (WSS) in the descending thoracic aorta (dAo). We created the first patient-specific computational fluid dynamics (CFD) model of a CoA patient treated by Palmaz stenting to date, and compared resulting WSS distributions to those from virtual implantation of Genesis XD and modified NuMED CP stents, also commonly used for CoA. CFD models were created from magnetic resonance imaging, fluoroscopy and blood pressure data. Simulations incorporated vessel deformation, downstream vascular resistance and compliance to match measured …

Long-Term Results Of Comprehensive Clubfoot Release Versus The Ponseti Method: Which Is Better?, Peter A. Smith, Ken N. Kuo, Adam Graf, Joseph Krzak, Ann Flanagan, Sahar Hassani, Angela Caudill, Frederick Dietz, Jose Morcuende, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background

Clubfoot can be treated nonoperatively, most commonly using a Ponseti approach, or surgically, most often with a comprehensive clubfoot release. Little is known about how these approaches compare with one another at longer term, or how patients treated with these approaches differ in terms of foot function, foot biomechanics, or quality-of-life from individuals who did not have clubfoot as a child.

Questions/purposes

We compared (1) focused physical and radiographic examinations, (2) gait analysis, and (3) quality-of-life measures at long-term followup between groups of adult patients with clubfoot treated either with the Ponseti method of nonsurgical management or a comprehensive …

A Robotic Test Of Proprioception Within The Hemiparetic Arm Post-Stroke, Lucia Simo, Lior Botzer, Claude Ghez, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Background: Proprioception plays important roles in planning and control of limb posture and movement. The impact of proprioceptive deficits on motor function post-stroke has been difficult to elucidate due to limitations in current tests of arm proprioception. Common clinical tests only provide ordinal assessment of proprioceptive integrity (eg. intact, impaired or absent). We introduce a standardized, quantitative method for evaluating proprioception within the arm on a continuous, ratio scale. We demonstrate the approach, which is based on signal detection theory of sensory psychophysics, in two tasks used to characterize motor function after stroke.

Methods: Hemiparetic stroke survivors and neurologically intact …