RE@CSU

Student Projects

Restoring Reaching to People with High Spinal Cord Injury

Faculty Mentor Eric Schearer

Schearer labInterface to design

Summary. Functional electrical stimulation neuroprostheses are the most promising means for restoring arm and hand functions to people with paralyzed arms. Due to the complexity in controlling the shoulder and elbow, the most advanced neuroprosthesis for controlling reaching movements relies on frequent tuning by a technical expert. However, constant changes in the strength and stiffness of muscles along with the large number of potential reaching movements do not lend well to a strategy based on frequent expert tuning. The objective of this project is to  coordinate electrical stimulation of multiple  muscles  to  evoke  reaching  movements  and  to  expand  and improve upon those reaching movements as a user’s muscles and goals change. The central hypothesis is that person-specific models of muscles’ responses to electrical stimulation can be learned and used to coordinate muscles to evoke reaching movements and that reaching movements can be improved and  expanded  with  tactile  feedback  from  a  nonexpert caregiver.

REU Student Involvement. The student(s) will design, manufacture, and test a wrist-mounted six-axis force sensing device that can be worn by a person with spinal cord injury. A caregiver could communicate corrections in the patient’s arm movements by providing tactile feedback at the wrist-mounted sensing device. We have developed preliminary designs from which the student(s)  can work. The student will conduct a literature search on similar devices, select, manufacture, and assemble the device’s components, create electronic and computing interfaces that read the sensor’s outputs, evaluate the device’s wearability on human subjects, and evaluate its accuracy.

Health Care and Patient Experience. Students will observe experiments with people with high spinal cord injuries at MetroHealth Old Brooklyn Health Center where Dr. Schearer regularly conducts human subjects experiments as a member of the Bioscientific Staff.

 

Balance Training in the Community

Faculty Mentor Ann Reinthal

MDHBT 20,000 leaksHigh tunnel

Summary. Balance is necessary for mobility, and independent mobility is a key to participating in numerous life activities. We are developing more effective interventions to improve balance including an inexpensive harness system that allows individuals to move, not only anteriorly and posteriorly, but also laterally. We hypothesize that the harness system will allow for more risk taking and therefore a higher intensity of safe practice than a non-harnessed environment where falls are possible. A critical gap in rehabilitation, however, is that improvements obtained in the clinical setting do not always transfer to an individual’s real-life activities. One explanation is that clinic-based activities are not similar enough to those in real life, lacking the necessary task and environmental complexity. The proposed project involves transitioning harnessed balance training from the lab into a community setting, specifically community gardening. This transition requires several necessary adaptations which will be the focus of this student project.

REU Student Involvement. The student(s) will develop inexpensive multidirectional harness system designs for several common community garden layouts (raised beds, high tunnels, etc.) and inexpensive active-assist mechanisms to assist during sit to stand and kneeling to stand. In designing the first component, the student will be introduced to several community garden sites, in particular sites where older adults or individuals with disabilities could potentially garden with the proposed adaptations. For the second component, the student will work both in the lab, first with normal and then balance impaired individuals, to develop a robust design.

Health Care and Patient Experience. This project has direct contact with human research subjects as described above and with Dr. Reinthal, who is a licensed physical therapist.

 

The Role of Tissue Properties on Simulated Knee Mechanics

Faculty Mentor Jason Halloran

Halloran labknee ligaments

Summary. Healthy knee mechanics are the result of a complex interaction between the involved tissues. Each tissue (e.g. ligaments, cartilage, meniscus, etc.) serves a purpose and has properties that enable ideal load sharing across the joint. Injury, disease and/or aging alter the overall mechanics of the joint, which can result in pain, loss of mobility and eventually, joint replacement or reconstruction. Knee models have offered one means to understand the load sharing pathway for both healthy and diseased states. Yet, whole joint modeling studies  typically assume properties based on literature reported values, even when it is known that uncertainty is present. Sources of uncertainty include the ability to accurately measure an individual tissue as well as variability across a population of individuals. Despite the prevalence of knee focused simulation studies, few have quantified the contribution of individual properties on predicted outcomes. A formal study that directly addresses this topic would serve two purposes. First, the effects of common modeling assumptions could be revealed and second, the relative importance of those assumptions could be found. This project will utilize already developed models to set up and use a framework for probabilistic simulation of knee mechanics.

REU Student Involvement. Students will explore the role of ligament reference lengths on resulting computational predictions of knee mechanics. Ligament reference lengths are difficult to measure experimentally, especially in the context of whole joint mechanics, and have particular relevance for ligament reconstruction procedures. With regards to rehabilitation engineering, this topic can be related to clinical success, where physicians directly or indirectly influence the load sharing pathway of the knee during many common interventions. Establishing the effect of relevant parameters will help quantify the consequences of clinical decisions and also provides a venue for undergraduate students to learn about the complexity of these problems.

Health Care and Patient Eexperience. REU participants will witness and document the steps in a joint reconstruction surgery (e.g. a total knee replacement or ligament reconstruction) performed by a collaborating physician at St. Vincent Charity Medical Center in Cleveland.

 

Laboratory Balance Training

Faculty Mentor Debbie Espy

load cell project

Summary. Falls are an enormous problem for older adults and adults with disabilities: they risk morbidity and mortality, and even non-injurious falls lead to significant limitations in mobility, independence, and community participation. Evidence shows that balance training can reduce fall risk, and that reactive (being perturbed) training may be more effective that proactive (self- initiated). Proactive training is more typical clinically though because it is perceived as easier and safer. Our research focuses on designing proactive interventions to reduce fall risk. This study involves both testing and training of balance under various conditions: playing challenging, full- body video games on difficult support surfaces (pro-active); being slipped in standing or while walking (reactive). For these activities, participants are in a harness designed to allow freedom of movement to recover their balance independently but which supports their weight and prevents an actual fall if they are not able to recover on their own. A load cell is used to monitor the forces exerted throughout. We will also investigate the impact of the harness on motor learning and the efficacy of the balance training.

REU Student Involvement. The REU student(s) will work on one or more of the following projects. 1) Designing, building, and incorporating a wireless load cell for the gait slip into the current experimental set-up. The current gait slip is limited by the tethered load cell and amplifier. 2) Setting up the instrumentation and writing code to allow online analysis of the load cell signal from the gait, standing, or gaming set ups for in-the-moment decisions about the subjects’ use of the harness as they learn the balance tasks. 3) Equipping the proactive harness system with a simple load cell that can alarm or indicate when the participant loads at greater than a certain force, to encourage decreasing reliance on the harness throughout training.

Health Care and Patient Experience. All three of these would involve iterative testing of the set-up with research participants who will be older adults or adults with conditions that put them at greater risk of falling.  These studies mimic clinical training settings.  The research participants are individuals with conditions that would lead them to receive physical therapy, balance training, and fall risk reduction.

 

Powered Prosthetic Leg Technology

Faculty Mentor Dan Simon

amputee walkingrobotic leg

Summary. The Embedded Control Systems Research Lab develops novel prosthetic leg technology. About two million people in the US are lower-limb amputees, and the number is rapidly expanding because of the increasing prevalence of diabetic vascular disease. Current prosthesis technology does not restore able-bodied gait, and leads to ancillary health problems because of the amputees need to compensate for the technology’s shortcomings. Improved prosthetic leg technology will allow amputees to lead longer, more active, more functional, more healthy, and more fulfilling lives. Recent advances in prosthesis control have demonstrated impressive performance, but control depends heavily on user activity. User activity can be inferred with electromyography (EMG), but EMG is invasive and inconvenient. Also, effective prosthesis controllers require state feedback, but state feedback sensors such as load cells are bulky, heavy, expensive, and prone to malfunction. There is thus an urgent need in the prosthetics field to devise novel approaches to user intent recognition and sensorless control for transfemoral prostheses.

REU Student Involvement. The REU student research will build on current NSF-sponsored prosthesis research at CSU and the faculty mentor’s expertise in computer intelligence to develop new real-time pattern recognition algorithms to classify user activity, relying only on easily-obtained signals such as joint angles. Preliminary results are promising but the approach requires new advances in sensor fusion. REU students will: (1) conduct literature review on pattern recognition; (2) conduct literature review on prosthesis user intent; (3) become familiar with basic evolutionary algorithms; (3) simulate prosthesis user intent recognition with established pattern recognition algorithms; (4) incorporate evolutionary optimization in pattern recognition algorithms for benchmark problems; (5) implement the preceding results for prosthesis user intent recognition; (6) evaluate the advantages and disadvantages of their new algorithms using prosthesis simulation frameworks currently available at CSU.

Health Care and Patient Experience. The REU student(s) will attend amputee clinics at the Cleveland VA. These clinics, currently held every month at the VA, involve training activities and interactions between prosthetists and amputees. These clinics will provide the student with an appreciation of the importance of user intent, and an appreciation of the prosthesis usability issues that are faced by amputees. The student will be expected to reflect on their experiences at the amputee clinics in a structured way, including thinking about how prosthesis user concerns should inform their user intent research.

 

Impact Force Sensing for Walking and Running

Faculty Mentor Hanz Richter

Piezo Shoe

Summary. Real-time measurement of ground reaction forces (GRF) associated with walking and running is critical in human kinetics studies and prosthetic and orthotic device design. GRF is typically measured using instrumented treadmills or force plates attached to a specific area of the walking surface. These methods preclude force data collection during free-range, extended movement, and impose limitations on the kinds of surfaces where walking and running take place. The goal of this project is to develop an instrumented shoe to eliminate these constraints. Based on preliminary studies, which involved one undergraduate student, insole-mounted piezoelectric films  are a viable sensing technology. These films are highly flexible and self-powered, producing output signals solely on the basis of mechanical energy conversion and harvesting. Processing of raw sensor signals to match actual forces is accomplished  by  neural networks.  The intellectual component of the project is focused neural network design, training and validation. Our experience with undergraduate students suggests that young students can grasp the essential concepts necessary to successfully design, train, and validate neural networks.

REU Student Involvement. Students will select piezoelectric film sensors according to ergonomic, economic and engineering criteria. They will determine the optimal distribution of sensors on the insole and prepare interfacing circuitry. Simultaneously, students will read material and receive instruction on neural networks and computer-aided tools that facilitate network training. Training and validation data collection will be carried out using an instrumented treadmill available in the Parker-Hannifin Human Motion and Control Lab at CSU. Network design and training will then be conducted. Principal component analysis for sensor re-selection, embedded design and wireless data transmission are possible extensions to the project, to be carried out in subsequent summers.

Health Care and Patient Experience. The REU student(s) will attend amputee clinics at the Cleveland VA. These clinics, currently held every month at the VA, involve training activities and interactions between prosthetists and amputees. These clinics will provide the student with an appreciation of the importance of user intent, and an appreciation of the prosthesis usability issues that are faced by amputees. The student will be expected to reflect on their experiences at the amputee clinics in a structured way, including thinking about how prosthesis user concerns should inform their user intent research.

 

Identification of feedback control in human movement

Faculty Mentor Ton van den Bogert

Ton projecttreadmill gait analysis

Summary. One of our research goals is to develop methods for identification and quantification of feedback control in human movement. This is motivated by the need to incorporate human-like control in powered prostheses and exoskeletons, but this also has potential clinical applications such as the diagnosis of neural deficits due to aging or disease.

REU Student Involvement. The goal of this student project will be to quantify reflex gains during walking. This will make use of a computer-controlled treadmill which can produce mechanical perturbations in various directions. The human response will be measured by electromyography (EMG). The student will program the system to apply one of several perturbations multiple times at the same time in the gait cycle. This will be done during a protocol of several minutes, randomly picking from a set of perturbations, so that the perturbations remain unexpected. The analysis will include signal processing to determine the EMG envelope, subtracting the baseline to highlight the reflex responses, and mapping the responses as a function of the gait cycle. This will be done in normal healthy participants. If successful, this will be extended to determine the effect of aging.

Health Care and Patient Experience. The REU student(s) will attend amputee clinics at the Cleveland VA. These clinics, currently held every month at the VA, involve training activities and interactions between prosthetists and amputees. These clinics will provide the student with an appreciation of the importance of user intent, and an appreciation of the prosthesis usability issues that are faced by amputees. The student will be expected to reflect on their experiences at the amputee clinics in a structured way, including thinking about how prosthesis user concerns should inform their user intent research.