Biomedical Engineering and Bioengineering Commons^™

Visual And Proprioceptive Contributions To Compensatory And Pursuit Tracking Movements In Humans, Megan L. Heenan, Robert A. Scheidt, Scott A. Beardsley

Biomedical Engineering Faculty Research and Publications

An ongoing debate in the field of motor control considers how the brain uses sensory information to guide the formation of motor commands to regulate movement accuracy. Recent research has shown that the brain may use visual and proprioceptive information differently for stabilization of limb posture (compensatory movements) and for controlling goal-directed limb trajectory (pursuit movements). Using a series of five experiments and linear systems identification techniques, we modeled and estimated the sensorimotor control parameters that characterize the human motor response to kinematic performance errors during continuous compensatory and pursuit tracking tasks. Our findings further support the idea that pursuit …

Quantifying Mitochondrial And Plasma Membrane Potentials In Intact Pulmonary Arterial Endothelial Cells Based On Extracellular Disposition Of Rhodamine Dyes, Zhuohui Gan, Said H. Audi, Robert D. Bongard, Kathryn M. Gauthier, Marilyn P. Merker

Biomedical Engineering Faculty Research and Publications

Our goal was to quantify mitochondrial and plasma potential (Δψ_m and Δψ_p) based on the disposition of rhodamine 123 (R123) or tetramethylrhodamine ethyl ester (TMRE) in the medium surrounding pulmonary endothelial cells. Dyes were added to the medium, and their concentrations in extracellular medium ([R_e]) were measured over time. R123 [R_e] fell from 10 nM to 6.6 ± 0.1 (SE) nM over 120 min. TMRE [R_e] fell from 20 nM to a steady state of 4.9 ± 0.4 nM after ∼30 min. Protonophore or high K⁺ concentration ([K⁺]), …

Instrument Independent Diffuse Reflectance Spectroscopy, Bing Yu, Henry L. Fu, Nirmala Ramanujam

Biomedical Engineering Faculty Research and Publications

Diffuse reflectance spectroscopy with a fiber optic probe is a powerful tool for quantitative tissue characterization and disease diagnosis. Significant systematic errors can arise in the measured reflectance spectra and thus in the derived tissue physiological and morphological parameters due to real-time instrument fluctuations. We demonstrate a novel fiber optic probe with real-time, self-calibration capability that can be used for UV-visible diffuse reflectance spectroscopy in biological tissue in clinical settings. The probe is tested in a number of synthetic liquid phantoms over a wide range of tissue optical properties for significant variations in source intensity fluctuations caused by instrument warm …

Cardiac Magnetic Resonance Imaging Can Detect Early Vascular Changes In Children With Type 1 Diabetes (T1dm), Margaret M. Samyn, Pippa Simpson, Michael E. Widlansky, Mary M. Krolikowski, Jennifer Co-Vu, Ronak Jashwant Dholakia, John F. Ladisa, Ramin Alemzadeh

Biomedical Engineering Faculty Research and Publications

No abstract provided.

A Quantitative And Standardized Robotic Method For The Evaluation Of Arm Proprioception After Stroke, Lucia Simo, Claude Ghez, Lior Botzer, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Stroke often results in both motor and sensory deficits, which may interact in the manifested functional impairment. Proprioception is known to play important roles in the planning and control of limb posture and movement; however, the impact of proprioceptive deficits on motor function has been difficult to elucidate due in part to the qualitative nature of available clinical tests. We present a quantitative and standardized method for evaluating proprioception in tasks directly relevant to those used to assess motor function. Using a robotic manipulandum that exerted controlled displacements of the hand, stroke participants were evaluated, and compared with a control …

A Novel Cable-Driven Robotic Training Improves Locomotor Function In Individuals Post-Stroke, Ming Wu, Jill M. Landry, Sheng-Che Yen, Brian D. Schmit, T. George Hornby, Miriam Rafferty

Biomedical Engineering Faculty Research and Publications

A novel cable-driven robotic gait training system has been tested to improve the locomotor function in individuals post stroke. Seven subjects with chronic stroke were recruited to participate in this 6 weeks robot-assisted treadmill training paradigm. A controlled assistance force was applied to the paretic leg at the ankle through a cable-driven robotic system. The force was applied from late stance to mid-swing during treadmill training. Body weight support was provided as necessary to prevent knee buckling or toe drag. Subjects were trained 3 times a week for 6 weeks. Overground gait speed, 6 minute walking distance, and balance were …

Effects Of Wrist Tendon Vibration On Targeted Upper-Arm Movements In Poststroke Hemiparesis, Megan O. Conrad, Robert A. Scheidt, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

Background. Impaired motor control of the upper extremity after stroke may be related to lost sensory, motor, and integrative functions of the brain. Artificial activation of sensory afferents might improve control of movement by adding excitatory drive to sensorimotor control structures. The authors evaluated the effect of wrist tendon vibration (TV) on paretic upper-arm stability during point-to-point planar movements. Methods. TV (70 Hz) was applied to the forearm wrist musculature of 10 hemiparetic stroke patients as they made center-out planar arm movements. End-point stability, muscle activity, and grip pressure were compared as patients stabilized at the target position …

A Database For Estimating Scanner-Specific Ct Dose, Taly Gilat-Schmidt

Biomedical Engineering Faculty Research and Publications

Purpose: To develop a database for estimating scanner-specific organ dose in a voxelized patient model for any spectral shape and angular tube current modulation setting. The database enables the estimation of organ dose for both existing and novel acquisition techniques without requiring Monte Carlo simulations.

Methods: The transport of monoenergetic photons through three phantoms was simulated with the PENELOPE Monte Carlo radiation transport routines at 5 – 150 keV in 1 keV increments at 1000 projections in 0.36 degree increments. The source-to-detector distance for each simulation was 100 cm, with a source-to-isocenter distance of 50 cm. The lateral and axial …

Biophysical Properties Of The Aorta In Patients With Marfan Syndrome And Related Connective Tissue Disorders: Evaluation With Mri And Computational Fluid Dynamics Modeling, Joseph A. Camarda, Michael G. Earing, Ronak Jashwant Dholakia, Hongfeng Wang, Sung Kwon, John F. Ladisa Jr., Margaret M. Samyn

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Sensory Motor Remapping Of Space In Human-Machine Interfaces, Ferdinando A. Mussa-Ivaldi, Maura Casadio, Zachary C. Danziger, Kristine M. Mosier, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Studies of adaptation to patterns of deterministic forces have revealed the ability of the motor control system to form and use predictive representations of the environment. These studies have also pointed out that adaptation to novel dynamics is aimed at preserving the trajectories of a controlled endpoint, either the hand of a subject or a transported object. We review some of these experiments and present more recent studies aimed at understanding how the motor system forms representations of the physical space in which actions take place. An extensive line of investigations in visual information processing has dealt with the issue …

Incorporating Feedback From Multiple Sensory Modalities Enhances Brain–Machine Interface Control, Aaron J. Suminski, Dennis C. Tkach, Andrew H. Fagg, Nicholas G. Hatsopoulos

Biomedical Engineering Faculty Research and Publications

The brain typically uses a rich supply of feedback from multiple sensory modalities to control movement in healthy individuals. In many individuals, these afferent pathways, as well as their efferent counterparts, are compromised by disease or injury resulting in significant impairments and reduced quality of life. Brain–machine interfaces (BMIs) offer the promise of recovered functionality to these individuals by allowing them to control a device using their thoughts. Most current BMI implementations use visual feedback for closed-loop control; however, it has been suggested that the inclusion of additional feedback modalities may lead to improvements in control. We demonstrate for the …

Aortic Coarctation: Recent Developments In Experimental And Computational Methods To Assess Treatments For This Simple Condition, John F. Ladisa, Charles A. Taylor, Jeffrey A. Feinstein

Biomedical Engineering Faculty Research and Publications

Coarctation of the aorta (CoA) is often considered a relatively simple disease, but long-term outcomes suggest otherwise as life expectancies are decades less than in the average population and substantial morbidity often exists. What follows is an expanded version of collective work conducted by the authors' and numerous collaborators that was presented at the 1st International Conference on Computational Simulation in Congenital Heart Disease pertaining to recent advances for CoA. The work begins by focusing on what is known about blood flow, pressure and indices of wall shear stress (WSS) in patients with normal vascular anatomy from both clinical imaging …

Correction To Mitochondrial Free [Ca2+] Increases During Atp/Adp Antiport And Adp Phosphorylation: Exploration Of Mechanisms, Johan Haumann, Ranjan K. Dash, David F. Stowe, Age D. Boelens, Daniel A. Beard, Amadou K.S. Camara

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Distribution Of Capillary Transit Times In Isolated Lungs Of Oxygen-Tolerant Rats, Madhavi Ramakrishna, Zhuohui Gan, Anne V. Clough, Robert C. Molthen, David L. Roerig, Said H. Audi

Biomedical Engineering Faculty Research and Publications

Rats pre-exposed to 85% O₂ for 5–7 days tolerate the otherwise lethal effects of 100% O₂. The objective was to evaluate the effect of rat exposure to 85% O₂ for 7 days on lung capillary mean transit time (t¯c) and distribution of capillary transit times (h _c(t)). This information is important for subsequent evaluation of the effect of this hyperoxia model on the redox metabolic functions of the pulmonary capillary endothelium. The venous concentration vs. time outflow curves of fluorescein isothiocyanate labeled dextran (FITC-dex), an intravascular indicator, and coenzyme Q₁ hydroquinone …

Detrimental Thoracoabdominal Interaction With Lateral Airbag Restraints, Jason John Hallman

Dissertations (1934 -)

Side impact motor vehicle crashes pose unique challenges for occupant protection, particularly with regard to torso injury mitigation. The minimal crush distance between the vehicle exterior and the occupant torso has necessitated advanced passive safety technologies in response to tightened regulatory requirements and increased public awareness of safety issues. In particular, lateral airbag restraints (side airbags) have undergone a rapid and unregulated introduction in recent years, with US availability increasing to over 90% of new vehicles in 2010. As with frontal airbag restraints, the prdissertationsity for injury to occupants in close proximity to side airbag deployment remains a concern. Test …

Development Of A Unique Whole-Brain Model For Upper Extremity Neuroprosthetic Control, Dominic Nathan

Dissertations (1934 -)

Neuroprostheses are at the forefront of upper extremity function restoration. However, contemporary controllers of these neuroprostheses do not adequately address the natural brain strategies related to planning, execution and mediation of upper extremity movements. These lead to restrictions in providing complete and lasting restoration of function. This dissertation develops a novel whole-brain model of neuronal activation with the goal of providing a robust platform for an improved upper extremity neuroprosthetic controller. Experiments (N=36 total) used goal-oriented upper extremity movements with real-world objects in an MRI scanner while measuring brain activation during functional magnetic resonance imaging (fMRI). The resulting data was …

Ankle Strength And Functional Limitations In Children And Adolescents With Type I Osteogenesis Imperfecta, Angela Caudill, Ann Flanagan, Sahar Hassani, Adam Graf, Ruta Bajorunaite, Gerald F. Harris, Peter A. Smith

Biomedical Engineering Faculty Research and Publications

Purpose: To determine whether children with type I osteogenesis imperfecta (OI) exhibit ankle plantar flexor weakness and whether this correlates with physical function.

Methods: Twenty children and adolescents with type I OI and 20 age-matched controls (age 6-18 years) participated in a single evaluation session. Data included strength assessment, Gillette Functional Assessment Questionnaire, Pediatric Outcome Data Collection Instrument (PODCI), and Faces Pain Scale—Revised.

Results: Ankle plantar flexor weakness was evident in the OI group compared with the control group. Heel-rise strength correlated with ankle isometric plantar flexion strength. Limitations in PODCI subscales—sports and physical function and pain/comfort—are present in the …

Validation Of A Micro-Ct Approach For Characterization Of Murine And Human Bone In Osteogenesis Imperfecta, John Jameson, Brooke Slavens, Robert Molthen, Peter Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Mitochondrial Free [Ca2+] Increases During Atp/Adp Antiport And Adp Phosphorylation: Exploration Of Mechanisms, Johan Haumann, Ranjan K. Dash, David F. Stowe, Age D. Boelens, Daniel A. Beard, Amadou K.S. Camara

Biomedical Engineering Faculty Research and Publications

ADP influx and ADP phosphorylation may alter mitochondrial free [Ca²⁺] ([Ca²⁺]_m) and consequently mitochondrial bioenergetics by several postulated mechanisms. We tested how [Ca²⁺]_m is affected by H₂PO₄⁻ (P_i), Mg²⁺, calcium uniporter activity, matrix volume changes, and the bioenergetic state. We measured [Ca²⁺]_m, membrane potential, redox state, matrix volume, pH_m, and O₂ consumption in guinea pig heart mitochondria with or without ruthenium red, carboxyatractyloside, or oligomycin, and at several levels of Mg²⁺ and P_i. …

Design And Validation Of An Mr Conditional Upper Extremity Evaluation System To Study Brain Activation Patterns After Stroke, Rubing Xu

Master's Theses (2009 -)

Stroke is the third leading cause of death and second most frequent cause of disability in the United States. Stroke rehabilitation methods have been developed to induce the cortical reorganization and motor-relearning that leads to stroke recovery. In this thesis, we designed and developed an MR conditional upper extremity reach and grasp movement evaluation system for the stroke survivors to study their kinematic performances in reach and grasp movement and the relationship between kinematic metrics and the recovery level measured by clinical assessment methods. We also applied the system into the functional MRI experiments to identify the ability to study …

Quantification Of 99mTc-Duramycin Uptake Kinetics In The Area-At-Risk After Myocardial Ischemia And Reperfusion, Joseph Capacete

Master's Theses (2009 -)

Myocardial infarction (MI) is a condition in which blood supply to the heart is insufficient. MI is associated with two forms of cell death: apoptosis and necrosis. ^99mTc-duramycin (^99mTc-D) is a novel radiopharmaceutical that detects cell death by recognizing externalized phosphatidylethanolamine. The objective of this study was to develop a compartmental model for ^99mTc-D uptake kinetics in normal and infarct myocardium, and utilize this model to compare the uptake kinetics of ^99mTc-D in MI with that of another radiopharmaceutical, ^99mTc-C2A-GST.

MI was induced in rats which were then injected (i.v.) with ^99mTc-D. Rats …

Local Hemodynamic Changes Caused By Main Branch Stent Implantation And Subsequent Side Branch Balloon Angioplasty In A Representative Coronary Bifurcation, Andrew R. Williams, Bon-Kwon Koo, Timothy J. Gundert, Peter J. Fitzgerald, John F. Ladisa Jr.

Biomedical Engineering Faculty Research and Publications

Abnormal blood flow patterns promoting inflammation, cellular proliferation, and thrombosis may be established by local changes in vessel geometry after stent implantation in bifurcation lesions. Our objective was to quantify altered hemodynamics due to main vessel (MV) stenting and subsequent virtual side branch (SB) angioplasty in a coronary bifurcation by using computational fluid dynamics (CFD) analysis. CFD models were generated from representative vascular dimensions and intravascular ultrasound images. Time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and fractional flow reserve (FFR) were quantified. None of the luminal surface was exposed to low TAWSS (/cm2) in the nondiseased bifurcation model. …

Visual, Motor And Attentional Influences On Proprioceptive Contributions To Perception Of Hand Path Rectilinearity During Reaching, Robert A. Scheidt, Kyle P. Lillis, Scott J. Emerson

Biomedical Engineering Faculty Research and Publications

We examined how proprioceptive contributions to perception of hand path straightness are influenced by visual, motor and attentional sources of performance variability during horizontal planar reaching. Subjects held the handle of a robot that constrained goal-directed movements of the hand to the paths of controlled curvature. Subjects attempted to detect the presence of hand path curvature during both active (subject driven) and passive (robot driven) movements that either required active muscle force production or not. Subjects were less able to discriminate curved from straight paths when actively reaching for a target versus when the robot moved their hand through the …

Image-Based Quantification Workflow For Coronary Morphology: A Tool For Use In Next-Generation Bifurcation Stent Design, Sara Marie Nomeland

Master's Theses (2009 -)

Coronary artery disease (CAD) occurs in ~200,000 bifurcation lesions annually. Treatment of CAD near bends and bifurcations is challenging and a preferred strategy for bifurcation lesions has yet to be established. However, a favorable treatment option may be elucidated by a more thorough understanding of vessel morphology as well as local hemodynamic alterations caused by current stenting approaches. Computational modeling of human arteries offers an attractive way to investigate the relationships between geometry, hemodynamics and vascular disease. Recent developments also make it possible to perform analysis on realistic geometries acquired noninvasively.

The objective of this work was twofold. The first …

Epidermal Neural Crest Stem Cell (Epi-Ncsc)--Mediated Recovery Of Sensory Function In A Mouse Model Of Spinal Cord Injury, Yao Fei Hu, Krishnaj Gourab, Clive Wells, Oliver Clives, Brian D. Schmit, Maya Sieber-Blum

Biomedical Engineering Faculty Research and Publications

Here we show that epidermal neural crest stem cell (EPI-NCSC) transplants in the contused spinal cord caused a 24% improvement in sensory connectivity and a substantial recovery of touch perception. Furthermore we present a novel method for the ex vivo expansion of EPI-NCSC into millions of stem cells that takes advantage of the migratory ability of neural crest stem cells and is based on a new culture medium and the use of microcarriers. Functional improvement was shown by two independent methods, spinal somatosensory evoked potentials (SpSEP) and the Semmes-Weinstein touch test. Subsets of transplanted cells differentiated into myelinating oligodendrocytes. Unilateral …

Bi-Planar Postural Stability Model: Fitting Parameters To Patient Data Automatically, Andrew Michael Sovol

Master's Theses (2009 -)

Studies of children with cerebral palsy (CP) have shown that maintaining control of posture in quiet standing is often difficult. Physical therapy and assistive devices, both with or without surgery, may be employed in an effort to improve postural stability. Assessing the effectiveness of such interventions is important for healthcare providers and their patients. A previously created bi-planar model of posture control has been further developed as a method of assessment. This MATLAB and Simulink model has successfully replicated experimental results for typical adults and children, as well as children with CP across three different test conditions: eyes open, eyes …

Upper Extremity Kinetics During Lofstrand Crutch-Assisted Gait In Children, Neha Bhagchandani

Master's Theses (2009 -)

Complete biomechanical analysis helps evaluate the motion during various gait patterns for the upper and lower extremities. Extensive studies have been performed to evaluate unassisted gait patterns, but very little has been accomplished for studying assisted motion. Children with pathologies such as osteogenesis imperfecta, spinal cord injury, and cerebral palsy use assistive devices such as anterior and posterior walkers, canes, Lofstrand and axillary crutches for ambulation purposes.

Statistics show that there are currently about 566,000 crutch users in the United States. The long-term crutch users in this population can suffer various upper limb pathologies associated with extensive upper extremity (UE) …

A Non-Rigid Registration Method For Analyzing Myocardial Wall Motion For Cardiac Ct Images, Elizabeth B. Philps

Master's Theses (2009 -)

Cardiac resynchronization therapy (CRT) has a high percentage of non-responders. Successfully locating the optimal location for CRT lead placement on a priori images can increase efficiency in procedural preparation and execution and could potentially increase the rate of CRT responders.

Registration has been used in the past to assess the motion of medical images. Specifically, one method of non-rigid registration has been utilized to assess the motion of left ventricular MR cardiac images. As CT imaging is often performed as part of resynchronization treatment planning and is a fast and accessible means of imaging, extending this registration method to assessing …

Sensitivity Of Motor Adaptation To The Statistical Properties Of An Environmental Load, Timothy Michael Haswell

Master's Theses (2009 -)

Linear, limited-memory models capture many important features of adaptive motor performance during reaching, stepping and pointing. A recent study in our lab found that a model fitted to data obtained from subjects reaching against elastic loads which varied from trial-to-trial later failed to fit the steady-state response behavior of subjects exposed to deterministic, step changes in load. Does motor adaptation depend on statistical properties of the environment (eg. mean load strength and variability)? Neurologically intact volunteers (n=14) made 6 blocks of 100 planar, ballistic, 10cm, out-and-back reaching movements against spring-like loads having equilibrium positions at the hand's starting point. View …

Ct Energy Weighting In The Presence Of Scatter And Limited Energy Resolution, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Purpose: Energy-resolved CT has the potential to improve the contrast-to-noise ratio(CNR) through optimal weighting of photonsdetected in energy bins. In general, optimal weighting gives higher weight to the lower energy photons that contain the most contrast information. However, low-energy photons are generally most corrupted by scatter and spectrum tailing, an effect caused by the limited energy resolution of the detector. This article first quantifies the effects of spectrum tailing on energy-resolved data, which may also be beneficial for material decomposition applications. Subsequently, the combined effects of energy weighting, spectrum tailing, and scatter are investigated through simulations.

Methods: The study first …