Biomedical Engineering and Bioengineering Commons^™

Virtual Reality Visual Feedback And Its Effect On Brain Excitability, Soha Saleh

Dissertations

This dissertation examines manipulation of visual feedback in virtual reality (VR) to increase excitability of distinct neural networks in the sensorimotor cortex. The objective is to explore neural responses to visual feedback of motor activities performed in complex virtual environments during functional magnetic resonance imaging (fMRI), and to identify sensory manipulations that could further optimize VR rehabilitation of persons with hemiparesis. In addition, the effects of VR therapy on brain reorganization are investigated. An MRI-compatible VR system is used to provide subjects with online visual feedback of their hand movement. First, the author develops a protocol to analyze variability in …

Upper Extremity Rehabilitation Using Interactive Virtual Environments, Qinyin Qiu

Dissertations

Stroke affects more than 700,000 people annually in the U.S. It is the leading cause of major disability. Recovery of upper extremity function remains particularly resistant to intervention, with 80% to 95% of persons demonstrating residual upper extremity impairments lasting beyond six months after the stroke. The NJIT Robot Assistive Virtual Rehabilitation (NJIT-RAVR) system has been developed to study optimal strategies for rehabilitation of arm and hand function. Several commercial available devices, such as HapticMaster™, Cyberglove™, trakSTAR™ and Cybergrasp™, have been integrated and 11 simulations were developed to allow users to interact with virtual environments. Visual interfaces used in these …

Alterations In Brain Connectivity After Spinal Cord Injury Using Functional Mri, Yamin Ahmed Noor

Theses

Every year, approximately 50 people per million of inhabitants are inflicted by Spinal Cord Injury (SCI). The long-term impairment of the SCI patients has led researchers to investigate different rehabilitation and treatment efforts that require careful observations to be made on reliable markers. Presently, a number of neuropsychological assessments are used for SCI rehabilitation and research purposes. However, there is a need for the discovery of sensitive biomarkers that can be used to characterize SCI. Altered functional connectivity in the brain has been observed in a number of neurological patient populations. Hence, it was hypothesized that such alterations in brain …

Fmri Assessment Of Ischemic Stroke In Humans, Rui Yuan

Theses

Cerebral ischemia, or brain ischemia is a kind of stroke where the blood flow is insufficient to the metabolic demand of brain. The lack of oxygen supply will directly lead to the death of brain tissue. There are two major injury regions: the infarct and penumbra. Mostly, since the infarct regions became dead tissues rapidly after stroke, there is a tiny possibility to rescue them in time. But penumbra parts are different. Tissues there will be viable for hours after ischemia. Hence, both theoretically and practically, it is possible to salvage those cells in the penumbra region. Diffusion weighted image …

Analysis Of Tissue Engineering Strategies For Bone-Related Applications, Timothy Buirkle

Theses

Over the past few decades, tissue engineering approaches have pushed their way to the forefront of biotechnological research and development, serving a wide variety of applications. This research utilizes quantitative methods to analyze the outcome of two bone tissue engineering studies. In an in vivo study, the use of Negative Pressure Wound Therapy (NPWT) in combination with stem cell-loaded scaffolds was investigated for the repair of large bone defects. Quantitative histological analysis was performed by determining both the percentage of cells proliferating (BrdU), as well as cells expressing bone-specific markers of alkaline phosphatase (A L P) in the defect. Total …

Quantifying Prehension In Persons With Stroke Post Rehabilitation, Saumya Sara Puthenveettil

Theses

This study describes the analysis of reaching and grasping abilities of the hemiparetic arm and hand of patients post stroke after a series of interactive virtual reality (VR) simulated training sessions and conventional physical therapy of similar intensity. Six subjects participated in VR training and five subjects in clinical rehabilitation for two weeks. Subjects’ finger joint angles were measured during a kinematic reach to grasp test using CyberGlove® and arm joint angles were measured using the trackSTARTM system prior to training and after training. Downward force applied to the object during grasping was assessed using Nano17TM, a force/torque sensor system …

Experimental Evaluation Of Near Infrared Light Penetration Into Neural Tissue, Ujwal Anil Parikh

Theses

Near infrared (NIR) lasers find applications in medicine both for diagnostic and treatment purposes. Penetration depth into the tissue is a critical parameter to be considered in these NIR laser applications. Published data on the optical properties of rodent neural tissue are rare, despite the frequent use of rats as animal models. The aim of this study was to directly measure the light intensity profile inside the rat brain gray matter that is illuminated by an NIR laser beam. The local light intensities were sampled using an optical fiber inserted into the brain. The intensity profile in the axial direction …

Cerebral Spasticity Modeled As Disorded Equilibrium Point Control, Darnell Simon

Dissertations

Spasticity is a highly complex phenomenon, which has not been defined in precise and quantifiable terms. Although the muscle stretch reflex is thought to play an important role in spasticity generation, the pathophysiologic basis of spasticity is not completely understood. A valid measure of spasticity is one that is chosen within the context of a theory describing the physiological mechanisms underlying the control of posture and movement in healthy individuals and possible impairments of these mechanisms leading to motor disorders. This research’s goal was to determine the role of stretch reflex threshold in the regulation of impaired motor control through …

Neuralsta: A Software Tool For Neural Stimulation And Recording Applications With A Laser Control, Rimi Sahu

Theses

The subject of this thesis is a software tool created in Matlab ® for neural stimulation and recording of the evoked potentials. The stimulation output can be delivered in electrical units for immediate use for neural stimulation or as a power control signal to a laser. NeuralSTA is designed to generate arbitrary waveforms of stimulation and simultaneously record the neural response while implementing the spike triggered averaging (STA) method, hence the name NeuralSTA. The output (stimulation) signal can be created in monophasic, biphasic or inverted monophasic forms (for laser control applications). Controls for pulse modulation allow shaping of the pulse …

Neural Differentiation Of Pluripotent Stem Cells And Applications To Micropatterned Agarose Hydrogel For Nerve Guidance, Jamila S. Gittens

Theses

Many central nervous system (CNS) disorders are attributable to damaged oligodendrocytes, the cells that form the myelin sheath of axons. An effective source of human oligodendrocytes is crucial, making pluripotent stem cells, such as embryonic stem (ES) cells, an attractive source for nerve tissue repair and regeneration due to their unlimited capacity for self-renewal and their ability to differentiate into all major cell lineages. Bioengineered 3-D hydrogel culture systems have the potential to elucidate mechanisms required for regeneration of CNS cells. The goals of this study are: (1) to investigate the effects of retinoic acid (RA), sonic hedgehog (shh) agonist, …

Temperature Elevations Due To Nir Exposure In The Brain Tissue, Ali Ersen

Theses

Near infrared (NIR) lasers have been used in medical applications both for diagnostic and therapeutic purposes. Temperature elevation profile inside the tissue is a critical factor that needs to be better understood in these applications. The purpose of this study is to determine the temperature distribution due to a low power N I R laser irradiation in living neural tissue. Temperature measurements were made directly using a thermocouple probe inside the rat brain cortex within the sagittal plane. The spatial map indicates that N I R light penetrates more readily in the vertical directions than the spreading in the horizontal …

Soy Protein-Poly (L-Lactic Acid) Blend Nanofibers For Drug Delivery Of Nardostachys Jatamansi, Swetha Tiwari

Theses

Electrospun nanofibers when nanofi bers are impregnated with drugs play a significant role in drug delivery. Nanomedical approaches to drug delivery focus on developing nanoscale particles or molecules to improve the bioavailab ility of a drug.

Biodegradable nanofibers were developed using Poly (L – lactic acid) and Soy protein for the delivery of an ayurvedic drug, Nardostachys jatamansi. A weighed quantity of powdered drug – Nardostachys Jatamansi was subjected to Soxhlet extraction using water and ethanol in equal quantities. Various blends of the drug extract and soy protein solution are prepared and mixed in Poly (L-lactic acid). Nanofibers of …

Alendronate Treatment Elicits A Reduction In Fatigue-Life Of Canine Cortical Bone, Joseph Ryan Geissler

Theses

Bone serves contradictory needs; bone must be strong yet light, and stiff yet flexible. At the tissue level bone material withstands cyclic loading without failing by dissipating energy via the formation and accumulation of microdamage. Proper removal of this damage in exchange for fresh tissue is vital to bone maintenance, and is achieved through a remodeling process. Imbalanced remodeling leads to osteoporotic fractures. Bisphosphonate drugs are proven to reduce fracture risk. However, the long-term effects of bisphosphonates on tissue-level properties are unknown. This study characterized the fatigue-life of cortical bone tissue after bisphosphonate treatment with alendronate (Aln). 1 1th ribs …

Theoretical Prediction Of Joint Reaction Force In A Dynamic General 3-D Pendulum Tree Model For Human Or Animal Motion, Sucheta Goyal

Theses

Lagrangian dynamics and the method of superfluous coordinates are applied to predict dynamic joint reaction forces in an idealized flexible model of a branched 3-D pendulum tree system. The number of segments and joints on the tree are adjustable as is the branching tree pattern. The segments that comprise the tree are assumed to be one- dimensional rigid rods containing a discrete set of mass points that is both flexible in number and distribution on the tree. The idealized 3-D pendulum tree system is intended to provide a flexible theoretical framework to model and better understand the dynamics of human …

Development Of 3-D Liver Model For Drug Screening Applications, Divya Rajendran

Theses

The need for a an in vitro drug screening system that mimics the structural organization of natural liver for multi-functionality and maintenance of hepatocytes has become vital in the drug development process. The objective of this study was to engineer a three-dimensional (3-D) liver model using chitosan-based nanofiber scaffolds and co-culture system (adult rat hepatocytes and 3T3-J2 fibroblasts) to mimic the natural liver and to justify its application for in vitro drug screening. Chitosan nanofiber scaffolds were fabricated by electrospinning technique. In order to promote cell adhesion on the chitosan scaffolds, the scaffolds were coated with a cell adhesion molecule, …