Narcolepsy is a chronic neurological disorder caused by the brain’s inability to regulate sleep wake cycles normally [1]. Narcoleptic patients feel overwhelmingly tired and sleepy. They do not have the ability to carry out normal day time activities, such as work or study, hence proper treatment is essential. In order to provide an accurate diagnosis of the sleep disorder, physicians must analyze the sleep stages of the patient. Sleep staging analysis is the process of extracting sleep information with brain signals known as electrophysiological signals. There are three major electrophysiological signals: Electroencephalograms (EEG), Electro-oculograms (EOG), and Electromyograms (EMG). Through the three signals, physicians and technicians can classify the sleep stages. Although all three signals are important, most physicians and researchers agree that 95% of information can be extracted from EEG signal. With the current technology, patients must go to the hospital and sleep there over night to perform the sleep stage studies. Electrodes are placed on their scalp, eyelids and skin for this examination. Often patients feel that it is very inconvenient and time consuming. Moreover, the technicians are prone to make human errors during the classification of the sleep stages. These errors are a result of fatigue that the technicians experience while doing the long process of classification of the sleep stages, and the complexity and ambiguity of the rules to determine the sleep stages. Our research group has worked together to construct a portable device that will provide advice to the narcolepsy patient for activity planning and medication dosage. In addition, it provides fore-warning to the patients prior to an narcoleptic attack. This device will also perform real-time sleep analysis and alertness assessment through processing of electroencephalogram (EEG) signal. The classification accuracy is extremely important to the development of this device. With high accuracy of the classifier, treatment for the patients can be determined more accurately by the physicians. As a result, the main purpose of the research presented in this thesis is to analyze different classification methodology and to optimize the parameters of each technology to obtain the optimal sleep stage classification results. The thesis will also present the description of the portable device and its components used for the development of the prototype.

Narcolepsy is a chronic neurological disorder caused by the brain’s inability to regulate sleep wake cycles normally [1]. Narcoleptic patients feel overwhelmingly tired and sleepy. They do not have the ability to carry out normal day time activities, such as work or study, hence proper treatment is essential. In order to provide an accurate diagnosis of the sleep disorder, physicians must analyze the sleep stages of the patient. Sleep staging analysis is the process of extracting sleep information with brain signals known as electrophysiological signals. There are three major electrophysiological signals: Electroencephalograms (EEG), Electro-oculograms (EOG), and Electromyograms (EMG). Through the three signals, physicians and technicians can classify the sleep stages. Although all three signals are important, most physicians and researchers agree that 95% of information can be extracted from EEG signal. With the current technology, patients must go to the hospital and sleep there over night to perform the sleep stage studies. Electrodes are placed on their scalp, eyelids and skin for this examination. Often patients feel that it is very inconvenient and time consuming. Moreover, the technicians are prone to make human errors during the classification of the sleep stages. These errors are a result of fatigue that the technicians experience while doing the long process of classification of the sleep stages, and the complexity and ambiguity of the rules to determine the sleep stages. Our research group has worked together to construct a portable device that will provide advice to the narcolepsy patient for activity planning and medication dosage. In addition, it provides fore-warning to the patients prior to an narcoleptic attack. This device will also perform real-time sleep analysis and alertness assessment through processing of electroencephalogram (EEG) signal. The classification accuracy is extremely important to the development of this device. With high accuracy of the classifier, treatment for the patients can be determined more accurately by the physicians. As a result, the main purpose of the research presented in this thesis is to analyze different classification methodology and to optimize the parameters of each technology to obtain the optimal sleep stage classification results. The thesis will also present the description of the portable device and its components used for the development of the prototype.

Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Please refer to full text for abstract.

No description available.

Medical device usability directly impacts the practitioner's ability to perform their diagnostic task in an effective, efficient, and safe manner. A device with poor usability may frustrate the practitioner, increasing the worker's stress level in a high-stress work environment. In addition, a device with poor usability may facilitate operator error, increasing the patient's risk of injury. Designers of healthcare systems and devices face a unique conundrum that has been documented in the literature (Martin, Murphy, Crowe, & Norris, 2006; Martin, Norris, Murphy, & Crowe, 2007; Ward & Clarkson, 2007). Standards require the use of user research techniques, yet patient privacy standards prevent designers from observing users in context. The inability to observe users in their work environment impedes understanding the context-of-use. Since understanding context-of-use is required to ensure usability, further exploration into alternative methods for requirements gathering is needed. This study explored the storytelling as an elicitation method for medical device requirements by comparing the information elicited from nurses during requirements gathering for an infusion pump by two methods: focus groups followed by interviews (Group #1) and focus groups followed by storytelling sessions (Group #2). Results suggest further exploration of storytelling is warranted as Group #2 contributed similar quantity and breadth of information in significantly less time. Results also indicate potential support for the efficacy of storytelling within the healthcare domain as Group #2 participants contributed more distinct context-of-use information with an emphasis on the social context. Contributions of this study include a plan for mixed-method data analysis, a protocol for conducting a storytelling session, and a framework for defining requirements within the healthcare domain. / Master of Science

No description available.

The prevalence and use of medical devices in the home environment continues to grow in the United Kingdom (UK) and Worldwide. It is recognised that such devices offer significant benefits to both patients and the National Health Service in the UK. The design of home use medical devices however represents a considerable challenge to designers and manufacturers alike. Developing devices that are usable and understandable by inexperienced, lay or dexterity impaired users requires an understanding across a breadth of disciplines. Previous research in this field has explored these challenges in attempt to offer support for developers of home use medical devices. There have been very few studies however that have explored whether the design community actually need, want or use such guidance, before considering whether this literature is adopted correctly. Through case studies, an online survey and in depth interviews this thesis suggests that industry practitioners are sceptical of the value of design guidance towards user involvement in home use medical device design. Consequently the practitioners in this research make little or no use of the formal design methods and supportive guidance documents available to them. More typically, practitioners in the home use medical device field use their own personal experiences and knowledge from working in the industry to adapt their own approaches to design. This thesis reports that the greatest challenge to involving users in the design of home use medical devices are the internal corporate and traditionally hierarchical barriers between stakeholders within the design process. In contrast to previous research offering support for designers and developers of home use medical devices this thesis calls for a wider change in design practice to facilitate the application of usability principles. As a conclusion to this thesis, recommendations for further research to address these changes in practice are proposed to industry professionals in the medical device industry. This thesis is submitted as part of the requirement for the Degree of Doctor of Philosophy at Loughborough University.

The purpose of this research was to investigate the application of design processes to the development of novel self-use molecular diagnostic devices for sexually transmitted infections. The argument proposed in this thesis is that the application of design methods at the earliest research stages into miniaturised, low cost, molecular diagnostic technologies will accelerate and improve the process of translating proof of concept diagnostic technologies into usable devices. Concept development requirements and potential issues and barriers to development were identified through interviews with expert stakeholders. These requirements were further refined through a survey of a multidisciplinary diagnostic medical device research group. An action research method was applied to develop a proof of concept prototype to the preclinical trial stage. Through these research studies, a design process model was formulated for use in a research environment. The application of design methods to the proof of concept prototype described in the thesis have resulted in a preclinical trial prototype that exhibits the necessary features for development into a self-use molecular diagnostic device. Issues and barriers were identified and discussed, design guidelines for further development beyond preclinical trial were defined and a generalised design process model for self-use molecular diagnostic devices for sexually transmitted infections was proposed. This research highlights the need for design methods to be applied at the earliest possible stages of the development of novel molecular diagnostic devices.

Guidewires have been used in many operating rooms by vascular surgeons to assist them in positioning and maneuvering through a tortuous stenosis or lesion to a desired location, and to be used as a guide for the implantation of a catheter. Surgeons are tasked with having to insert a guidewire inside a small cavity, which requires a high level of skill and patience. The insertion of the guide wire is controlled by a torque device, which allows a surgeon to advance, rotate and grip the wet hydrophilic coating of the guidewire. Despite its many advantages, the torque device does, in fact, give rise to many time consuming issues that results in delays to the surgical procedure. One main problem in the use of the torque device is that it is introduced through the proximal end of the guidewire. Therefore, it requires the assistance of another individual, the surgical technician, to advance the torque device from the furthest point away from the patient. Once the torque device is in position, it is up to the surgeon to attempt to control the tightening, advancing and loosening of the device all with one hand. The other, free hand is used as a placement hand to secure the positioning of the guidewire within the patient. Another issue arises in the removal of the torque device, which must be loosened with one hand and slid off the same end it was introduced, often resulting in the unwanted ejection of the guide wire tip from within the patient's body. The process must then commence from the start, resulting in loss of valuable time, and be repeated until the distal tip of the guidewire is secure in the desired location and the catheter can now be introduced. The main purpose of this research is to investigate, design, and develop a new guidewire torque device to facilitate in a more controlled manipulation of a guidewire by vascular surgeons. Through in-depth interviews with both surgeons and surgical residents alike, direct observational time in the vascular surgery OR (operating room), and I obtained knowledge used as a design basis for the development of the product. For example, observations of relevant medical procedures were also accomplished at Tampa General Hospital to establish a basis for the design,and to assess current vascular surgery medical procedures. Initial design concepts where created using SolidWorks CAD software. After a period of researching and understanding user needs, an assortment of non-slip adhesives where found to be a viable solution to the problem. A characterization analysis was done on the highest rated non-slip adhesive to further define design parameters, and pave the way for FDA approval and product commercialization.

Surface acoustic wave (SAW) devices find uses in a plethora of applications including but not limited to chemical, biological sensing, and microfluidic actuation. The primary aim of this dissertation is to develop a SAW biosensor, capable of simultaneous detection of target biomarkers in fluid media at concentrations of picogram/ml to nanogram/ml levels and removal of non-specific proteins from sensor surface using the process of acoustic streaming, for potential chemical sensing, medical, and clinical diagnostic applications. The focus is on the development of three dimensional finite element structural and fluid-structure interaction models to study wave propagation and acoustic actuation of fluids in a SAW biosensor. This work represents a significant improvement in understanding fluid flow over SAW devices, over the currently available continuum model of Nyborg. The developed methodology includes use of a novel substrate, namely, Langasite coupled with various combinations of novel multidirectional interdigital transducer (IDT) configurations such as orthogonal, focused IDTs as well as sensor surface modifications, such as micro-cavities. The current approach exploits the capability of the anisotropic piezoelectric crystal to launch waves of different characteristics in different directions, which can be put to the multiple uses including but not limited to sensing via shear horizontal waves and biofouling elimination via Rayleigh wave induced acoustic streaming. Orthogonal IDTs gives rise to constructive interference, thereby enhancing the magnitudes of device displacements and fluid velocities. The net effect is an increase in device sensitivity and acoustic streaming intensity. The use of micro-cavities in the delay path provides a synergistic effect, thereby further enhancing the device sensitivity and streaming intensity. Focused IDTs are found to enhance the device displacements and fluid velocities, while focusing the device displacements and fluid motion at the device focal point, thereby enhancing the SAW device biosensing performance. The work presented in this dissertation has widespread and immediate use for enhancing sensor sensitivity and analyte discrimination capabilities as well as biofouling removal in medical diagnostic applications of SAW sensors. This work also has a broad relevance to the sensing of multiple biomarkers in medical applications as well as other technologies utilizing these devices such as microfluidic actuation.