Matching Items (5)
Description
In this project, an existing waveform generator designed by the vagus nerve stimulation (VNS) technology firm Hoolest Performance Technologies was modified and characterized. Voltage feedback and current feedback systems were designed in order to improve output voltage and current regulation. A wireless communication system was implemented onboard the newly designed waveform generator in order to improve user experience and allow the system to be controlled remotely. Finally, a custom printed circuit board was designed according to the established circuit schematics for the above components, and the layout was miniaturized to a total board footprint area of 1.5 square inches. The completed device was characterized according to several figures of merit including current consumption, voltage and current regulation, and short-circuit behavior.
ContributorsPatterson, John Michael (Author) / Kozicki, Michael (Thesis director) / Mian, Sami (Committee member) / Electrical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The avalanche of ongoing bioscience research has resulted in an unprecedented range of opportunities for the creation of new medical diagnostics and therapies. As the potential to develop treatments for the human body expands, the ability to control, modify, and interfere with abstract parts of an individual's self increases. While basic components of the self - such as the mind, consciousness, and personality - can presently only be altered by natural processes and diseases, current and emerging technologies that can cause changes in the self are in development. It is likely that as understanding of the brain and mind increases, scientists and engineers will be develop the ability to alter the mind and consciousness in profound new ways. Such a paradigm shift will be fraught with ethical concerns, and if those concerns are not handled in an appropriate manner, there is significant potential for harm. This potential for causing harm is not without precedent. Genome editing technology is an area of research which deals with an element of the fundamental self. In recent years, advancements in genome editing technology in the form of the CRISPR/Cas9 system have caused alarm and debate within scientific communities concerning the ethicalness of its use and application. Using lessons learned from the ways in which the CRISPR technology has been beneficially used, an ethical framework might be developed in order to guide the development of emerging neurotechnology. Early implementation of a framework such as the one herein proposed could guide research that is already being conducted. There is still time to influence the way that neurological device research is conducted, and it is duty of ethical scientists in this field to understand and correct these problems clearly and quickly so as to prevent harm. An ethical framework that is consistent with current ethical standards and understandings might be created by reviewing the history and development of CRISPR.
ContributorsHislop, Joshua Jamie (Author) / Coursen, Jerry (Thesis director) / Helms Tillery, Stephen (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
An improved system for wireless neurostimulation was investigated through the design and development of sub-millimeter piezoelectric devices. The devices build on prior work in the lab, which was limited by device size and required surgical implantation. A method of manufacturing sub-mm devices was developed, and utilized to construct this new design. The device frequency response was characterized and its resonant modes and output voltages determined through a Fast Fourier Transform. The fundamental thickness mode frequency was found to be 15.4MHz with a corresponding 10.25mV amplitude, and a longitudinal resonant frequency of 3.1Mhz with a corresponding 2.2mV amplitude across a 50Ω resistor. The high miniaturization of the device holds promise for future work for creating an injectable, wireless system for the treatment of neurological disorders.
ContributorsCatchings, Michael Thomas (Author) / Towe, Bruce (Thesis director) / Muthuswamy, Jitendran (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Every year, 3 million older people are treated for fall injuries, and nearly 800,000 are hospitalized, many of which due to head injuries or hip fractures. In 2015 alone, Medicare and Medicaid paid nearly 75% of the $50 Billion in medical costs generated by falls. As the US population continues to age, more adults are beginning to deal with movement related disorders, and the need to be able to detect and mitigate these risks is becoming more necessary. Classical metrics of fall risk can capture static stability, but recent advancements have yielded new metrics to analyze balance and stability during movement, such as the Maximum Lyapunov Exponent (MLE). Much work has been devoted to characterizing gait, but little has explored novel way to reduce fall risk with interventional therapy. Targeting certain cranial nerves using electrical stimulation has shown potential for treatment of movement disorders such as Parkinson’s Disease (PD) in certain animal models. For human models, based on ease of access, connection to afferents leading to the lower lumber region and key brain regions, as well as general parasympathetic response, targeting the cervical nerves may have a more significant effect on balance and posture. This project explored the effects of transcutaneous Cervical Nerve Stimulation (CNS) on posture stability and gait with the practical application of ultimately applying this treatment to fall risk populations. Data was collected on each of the 31 healthy adults (22.3 ± 6.3 yrs) both pre and post stimulation for metrics representative of fall risk such as postural stability both eyes open and closed, Timed-Up-and-Go (TUG) time, gait velocity, and MLE. Significant differences manifested in the postural stability sub-metric of sway area with subject eyes open in the active stimulation group. The additional 8 metrics and sub-metrics did not show statistically significant differences among the active or sham groups. It is reasonable to conclude that transcutaneous CNS does not significantly affect fall risk metrics in healthy adults. This can potentially be attributed to either the stimulation method chosen, internal brain control mechanisms of posture and balance, analysis methods, and the Yerkes-Dodson law of optimal arousal. However, no adverse events were reported in the active group and thus is a safe therapy option for future experimentation.
ContributorsKreisler, Itai Goeta (Author) / Lockhart, Thurmon E (Thesis advisor) / Tyler, William J (Thesis advisor) / Wyckoff, Sarah (Committee member) / Arizona State University (Publisher)
Created2019
Description
Bioimpedance measurements have been long used for monitoring tissue ischemia and blood flow. This research employs implantable microelectronic devices to measure impedance chronically as a potential way to monitor the progress of peripheral vascular disease (PVD). Ultrasonically powered implantable microdevices previously developed for the purposes of neuroelectric vasodilation for therapeutic treatment of PVD were found to also allow a secondary function of tissue bioimpedance monitoring. Having no structural differences between devices used for neurostimulation and impedance measurements, there is a potential for double functionality and closed loop control of the neurostimulation performed by these types of microimplants. The proposed technique involves actuation of the implantable microdevices using a frequency-swept amplitude modulated continuous waveform ultrasound and remote monitoring of induced tissue current. The design has been investigated using simulations, ex vivo testing, and preliminary animal experiments. Obtained results have demonstrated the ability of ultrasonically powered neurostimulators to be sensitive to the impedance changes of tissue surrounding the device and wirelessly report impedance spectra. Present work suggests the potential feasibility of wireless tissue impedance measurements for PVD applications as a complement to neurostimulation.
ContributorsCelinskis, Dmitrijs (Author) / Towe, Bruce (Thesis advisor) / Greger, Bradley (Committee member) / Sadleir, Rosalind (Committee member) / Arizona State University (Publisher)
Created2015