(Georgia Institute of Technology, 2019-04-24)
Obrien, John James
The Wheelchair In-Seat Activity Tracker (WiSAT) is a sensor-based activity tracker aimed at encouraging in-seat movement among wheelchair users who are at risk of pressure ulcers. Pressure ulcers tend to form in the buttocks or thighs of a wheelchair user due to a lack of pressure redistribution in that part of the body. Pressure ulcers are a serious risk to many wheelchair users due to a plethora of harmful side-effects, such as infection, hospitalization, and long recovery times. However, in-seat movements, such as weight shifts, have been linked with the occurrence of pressure ulcers. WiSAT began as a research tool that enabled researchers to monitor the in-seat activity of wheelchair users during their daily lives through sensor-based reporting, as opposed to relying solely on the self-reporting of research participants. Through the efforts described in this thesis, WiSAT was transformed from a research tool into a consumer product. Specifically, this thesis describes the design, development, and integration of WiSAT’s subsystem through four specific aims:
1. Design and evaluation of a user-interface based upon principles of Health Behavioral Change Theory.
2. Coupling of the Hardware and Smartphone App Subsystems
3. Preparation of the Algorithm Subsystem
4. Integration of the WiSAT Subsystems through Multi-layered Architecture for the WiSAT Smartphone App
(Georgia Institute of Technology, 2006-05-22)
Prabhakara, Sandeep
Ultrasound is a valuable tool to monitor wound healing. In this report, ultrasound is used to determine the features in the B-scans that correspond to a bruise. High frequency ultrasound scans show clear and distinct features that correspond to a laceration or a late stage pressure ulcer. This is because of the extensive damage and the rupture of the epidermis in both the cases. This study assumes significance because it is an effort to find such artifacts in the ultrasound scans of bruises caused by blunt forces where the epidermis remains intact. In this study, the structure of the skin was visualized using a 20 MHz ultrasound scanner. Skin thickness and echogenicity changes may result due to blood extravasations or edema. The thickness and the echogenicity values are plotted against time to determine the trend in the variation of these parameters. We see an intraday and a daily fluctuation of skin thickness and echogenicity albeit with no distinct trend on a day to day basis or between subjects. The results also give us a good estimation of the variation observable in these parameters in the event of an injury. A snapshot analysis is also performed, which describes qualitatively the structural changes in the B-scan of the bruise site compared to the control site. There are six different types of qualitative changes which can appear in the B-scan of a bruised site compared to the control. In the event of an injury, usually, more than one of these changes is manifested in the scan of a bruise.
Skin thickness and echogenicity vary considerably due to a number of physiological factors which can seldom be controlled. Therefore, these parameters can give conclusive evidence of a bruise only if the change between a bruised region and a control region is much greater than the daily, normal variations. Snapshot analysis can help detect a bruise or a deep tissue injury. Further work involves the application of pattern recognition or face recognition algorithms to automate the detection.