Simulation of Hemiparetic Function Using a Knee Orthosis with Variable Impedance and a Proprioception Interference Apparatus

• Main Author: Lahiff, Christina-Anne Kathleen
• Format: Others
• Published: Scholar Commons 2017
• Subjects: Hyperextension; Spasticity; Hysteresis; Flexion; Rehabilitation; Mechanical Engineering
• Online Access: http://scholarcommons.usf.edu/etd/6623; http://scholarcommons.usf.edu/cgi/viewcontent.cgi?article=7820&context=etd

Individuals with stroke have neuromuscular weakness or paralysis on one side of the body caused by some muscles disengaging and overexciting other muscles. Hyperextension of the knee joint and complete lack of plantar flexion of the ankle joint are common symptoms of stroke. This thesis encompasses the simulation of hemiparetic function using both a knee orthosis with variable impedance, specifically in terms of stiffness and damping, and the Proprioception Interference Apparatus. The section regarding the knee orthosis with variable impedance focuses on the creation and implementation of a small, lightweight, and adjustable orthotic device to be positioned around the knee of an able-bodied person to simulate hemiparetic gait. Force and range of motion data from able-bodied subjects fitted with the orthosis, inducing hemiparetic gait, was collected using the Computer Assisted Rehabilitation ENvironment (CAREN) system. The four parameters that the design focused on are damping, catch, hysteresis, and stiffness. The main goal of the project was to discern whether this device could be utilized as a viable research instrument to simulate hemiparetic gait. It was hypothesized that the device has the potential to be utilized in the future as a research device to be used on able-bodied persons to study asymmetries in gait and eventually quantify the Modified Ashworth Scale. It was also believed that it could serve as a possible rehabilitation device for people with stroke since it has been designed to induce larger knee flexion as an after effect. However, this would require the proper clinical evaluation and experimentation procedures to be successfully concluded. A comparison between how the dominant leg was affected by the orthosis and how the non-dominant leg was affected was investigated as well. The results show that the device affected the velocities, knee angles, and force profiles of the subject’s gait. The second section involving the Proprioception Interference Apparatus involved the creation and implementation of a haptic apparatus that utilizes vibration as well as transcutaneous electrical nerve stimulation (TENS) in various combinations with and without visual feedback to induce a proprioceptive illusion around the knee joint, as if a subject has a version of hemiparesis. The main goal of the project was to discern whether a device of relatively the same design could be utilized as a viable research instrument to simulate stroke-like balance in able-bodied subjects. Comparison between how the root mean square (RMS) values of each marker location, the average of the standard deviations of the forces, and RMS of the center of pressure affected the various conditions was investigated as well. It was hypothesized and concluded that the RMS values and average of the standard deviations when subjects had no visual feedback would have a significant difference from when they had visual feedback. It was also hypothesized that Proprioceptive Interference Apparatus (PIA) would have a significant effect on the RMS and standard deviation values since it was meant to disrupt the motor control function of the knee, however, this was proved false after data analysis. It was also surmised that the application of the TENS had more of an effect on the RMS and standard deviation values, whether it was used on its own or in combination with the vibrations, than the vibration stimulation alone. However, once again, this was not statistically significant.