Spinal cord injuries (SCI) occur when damage to any part of the spinal cord is sustained. Depending on what vertebrae segment the injury occurs, the patient will develop paraplegia or tetraplegia and have a complete or incomplete spinal cord injury. After sustaining a spinal cord injury, the patient must undergo rehabilitation.

For incomplete SCI patients, part of their rehabilitation is improving their mobility skills through gait training. To assess gait, the methods of the clinical eye and laboratory gait assessment are used. The starting goal of the project was to combine the quickness and easiness of conducting a gait assessment with the clinical eye with the objective data from a laboratory gait assessment into one system. This system consists of Xsens Awinda wireless motion trackers to collect the kinematic data and a user interface to view it.

User research was conducted in the form of questionnaires and focus groups. The research aimed to learn more about how physiotherapists and physicians within Rijndam Revalidatie currently assess gait, what features and parameters they would like in the user interface, and how they would prefer the selected parameters to be visualized (in numbers, graphs, or animations). Three physiotherapists and physicians were also interviewed to better understand the process incomplete SCI patients go through in gait rehabilitation and who is involved in each step.

From the results, a design direction and vision was created: “To develop an easy to use user interface that aids physicians and physiotherapists in selecting interventions for patients with incomplete spinal cord injuries in an objective and time efficient manner through intuitive data visualizations.”

Using design methods and tools, ideas for the data visualizations and the interface layout were formed, selected, and then made into concepts. The layout and visualizations concepts were evaluated through concept test sessions with physiotherapists and physicians. In the sessions, the interface layout was assessed in terms of usability and functionality. The data visualizations were evaluated based on if the participants, who had minimal pre-existing knowledge on gait analysis, could understand them. From the evaluation results, the final design of Gait Vision was created.

Gait Vision is an easy-to-use interface that allows physiotherapists and physicians to assess gait objectively and time-efficiently. It provides more accurate and objective information than can be obtained with the clinical eye, in a way that is more intuitive and comprehensible for clinicians with minimal gait assessment experience than laboratory gait assessment.

An interactive prototype of the final design was developed using Adobe XD. The interface prototype and the visualization concepts were evaluated through conducting individual user tests with seven physicians and physiotherapists. The interface and visualizations were tested with regard to usability, functionality, intuitiveness, and aesthetics. Overall positive feedback was received regarding the interface and visualizations. Testing was also conducted to compare gait assessment with the clinical eye versus with the interface. The interface was found to more objective than the clinical eye.

An implementation plan was developed to ensure Gait Vision survives in the long term. Future recommendations were also made to aid in the continuation of the development of Gait Vision.

Falling is a significant problem for older adults. It can cause severe injury and even death. Furthermore, the fear of falling has a significant influence on the life of the elderly, and therefore they reduce their physical activity. Two new balance assistive devices are being developed to reduce the risk of falling. Both devices use a control moment gyroscope (CMG) to generate a moment to counter the falling motion. One device consists of a single CMG. The other device consists of two CMGs that are coupled such that the gimbals rotate in opposite direction. This is called a scissored pair CMG (SPCMG). The purpose of this study was to examine whether it is possible to design an (SP)CMG with a passive mechanism that exploits gyroscopic precession of gimbal(s) to emulate different types of impedances for balance assistance. To examine this, first, the equations of motion of a CMG and an SPCMG were derived. Next, the equations of motion were used to derive the impedance of the system. The impedance was optimized such that it would simulate the behaviour of a spring, a damper, a mass, a mass-spring-damper system, and a rotational PD controller which is proportional to the XCoM (PDXCoM), a measure of stability. The optimization used a gradient-based algorithm to find the minimum. Multiple optimizations with different random initial guesses were performed to increase the chance to find the global minimum. Two sets of optimizations were performed.
One optimization with and one optimization without bounds on the optimization. The sets parameters that led to the best fit were used in a walking simulation to calculate the moments the device would generate during normal walking. It is shown that it is possible to simulate the dynamics of a spring, a damper, a mass, and a mass-springdamper system with a CMG and an SPCMG. However, it was not possible to replicate the dynamics of the PDXCoM with a CMG and an SPCMG. A walking simulation showed that the generated moments of the (SP)CMG were in the opposite direction of the angular velocity of the human. Therefore, using a passive mechanism to control an (SP)CMG could be used as balance assistance.