Equipment set up for the hemispherical indenter test. The hemispherical indenter is resting on a mattress while a laptop runs a LabVIEW program that is graphing pressure data from each sensor.
While completing my undergraduate degree at the University of Maine in biomedical engineering, I discovered my passion for rehabilitation engineering and assistive technology. I had the opportunity to design and construct a pressure-alternating wheelchair cushion prototype for my senior capstone project.
The project's goal was to create a cushion that relieved pressure on the user’s ischial tuberosities (ITs), or “sit bones”, by cyclically adjusting the pressure within the cushion. While collecting background information for the project, I researched wheelchairs, cushions and pressure injury etiology. All aspects of the project interested me, so I was excited to continue to study those topics and more while in the School of Health and Rehabilitation Sciences (SHRS) Master of Rehabilitation Technology (MRT) program.
I decided to do the two-year plan of study in the MRT program in order to have the flexibility to gain valuable research experience while completing my master’s degree. After being accepted into the program, I discussed my interests and project experiences with Research Scientist Richard Schein. He connected me with Associate Professor Patricia Karg and the Associate Dean for Technology and Innovation and Professor David Brienza at the University of Pittsburgh Tissue Integrity Management (TIM) Laboratory, where I currently work part-time. My capstone experience fits in well with the TIM Lab’s research on wheelchair seating and support surfaces. Before working at the lab, I had briefly read a few International Organization for Standardization (ISO) and American Society for Testing and Materials (ASTM) standards, but I did not fully understand the scope and importance of industry standards for. Since working at the lab, I have seen the behind-the-scenes research that contributes to industry standards, and I have experience following testing protocols and collecting data according to standard procedures.
Eureka Moments in the Lab
2The hemispherical indenter resting on a mattress support surface. Sensors under the surface of the indenter are measuring how much pressure is being applied to the indenter.
My first project at the TIM Lab was getting an indenter for evaluating envelopment and immersion of support surfaces up and running. The indenter represents the overall shape and size of the ITs and gluteal region of a person in a seated position and has sixty-one pressure sensors under the surface that measure pressure as the indenter is lowered onto a support surface. The data collected from the indenter is used to evaluate each support surface’s envelopment, how well it conforms to the contours of the body, and immersion, how far the body sinks into the surface. This information is helpful for assessing the performance of support surfaces related to pressure injury prevention.
I enjoyed this project because I applied the topics I studied for my undergraduate degree and acquired new skills as well. I had some experience with National Instruments LabVIEW, a programming environment used to write programs to interface with data acquisition hardware systems, when I started at the lab. I created a program for the indenter that reads and displays signals from the indenter’s sensors and exports the raw data to Excel for processing. I knew how to code most of the program's functions, but I learned about other functions I did not know LabVIEW was capable of. The wires from the indenter were not long enough for our hardware setup, so I practiced my soldering skills while solving that problem. When debugging the hardware and software, I systematically worked my way through the various hardware and software components of the indenter to find where the errors were coming from. I enjoyed the process of testing a component, eliminating it as a potential source of error and thinking through what else could be causing the issues.
I viewed the project as a large puzzle and working out the solution was exciting! The project's first milestone was when all the sensors were responsive, and the LabVIEW program displayed a live graph of each sensor’s output signal. I was proud of the effort I had put in up to that point and very happy to see the indenter working properly! There were a few small surprises before the indenter was ready to be used for standards testing, but those have all been addressed and today the indenter is running smoothly!
A Curriculum Set Up for Research Success
The MRT curriculum covers various topics related to assistive technology and disability, and I have applied the knowledge and skills I gained during my research experience to my courses. For example, in the Client-Centered Design course (RT 2207), my experience with industry standards helped me develop a verification testing plan for my flexible drawer handle prototype. I had an idea of how I wanted to test my prototype and knew where to look to find applicable standards. In Clinical Applications of Seating and Mobility (RT2209), my research experience supplemented the course readings and lectures on wheelchair cushions and therapeutic support surfaces. The textbook’s descriptions were brief, but my hands-on experience with the cushions and mattresses in the lab helped me understand the surface features and material qualities described in the book.
Getting involved with research is a great way to apply your current skills, get hands-on experience developing new skills and supplement the material covered in the MRT curriculum. If you are considering doing research while in the MRT program, my advice would be to get involved! You never know what projects you may work on and what you may learn next!
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Written by Kacey Roehrich (MS ‘24)
Current Student in the Master of Rehabilitation Technology program
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Published April 3, 2023