Harter, Michelle
(2025)
Computational Modeling of Stability in Locomotion and the Effects of Vestibular Loss.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
The human body is unstable during walking and must be actively controlled. Four major strategies are used to maintain walking stability, including regulating foot placement, modulating lateral ankle roll, adjusting ankle push-off, and controlling trunk posture. These strategies use sensory feedback from the vestibular system, vision, and somatosensation. Deficits in the vestibular system are associated with decreased walking stability and increased fall risk. This dissertation used experimental and computational techniques to gain a greater understanding of how and why walking stability is impacted by vestibular impairment in people with vestibular hypofunction (PwVH) to suggest effective rehabilitation efforts. In Aim 1, I recruited healthy control participants (HCs) and PwVH to evaluate how these cohorts used the four strategies to maintain stability while walking with underfoot perturbations. HCs showed decreased stability following medial perturbations accompanied by decreased step width, increased ankle inversion, increased ankle push-off, and increased rightward trunk sway, with generally opposite changes for lateral perturbations. PwVH showed similar behavior; however, the response magnitudes were dependent on the side of the vestibular lesion and level of functional compensation. PwVH were more destabilized and had less effective trunk responses when perturbations caused acceleration toward the lesion. Additionally, poorly compensated PwVH were more unstable, showed exaggerated trunk and ankle responses, and walked slower. This aim highlighted the biomechanical differences associated with poor stability in PwVH. In Aim 2, I developed a computational model of human walking to understand why PwVH show poor gait stability and suggest mechanisms to improve stability. The model incorporated all stabilization strategies and responded to perturbations similarly to humans. Simulation results showed that exaggerated trunk sway can be attributed to vestibular loss, but poor stability is rather caused by PwVH walking more slowly. Normal trunk sway could be restored by reducing reliance on inaccurate vestibular input and increasing reliance on somatosensation. Stability could be improved by increasing step width. Together, these findings show how walking stability and stabilization strategies are affected in PwVH, why these differences arise, and how these impairments may be addressed through rehabilitation that modifies sensory reliance, walking speed, and the use of stabilization strategies.
Share
| Citation/Export: |
|
| Social Networking: |
|
Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
7 January 2025 |
| Date Type: |
Publication |
| Defense Date: |
22 October 2024 |
| Approval Date: |
7 January 2025 |
| Submission Date: |
7 October 2024 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
168 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Bioengineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
walking stability, vestibular loss |
| Date Deposited: |
07 Jan 2025 21:02 |
| Last Modified: |
07 Jan 2025 21:02 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/46996 |
Metrics
Monthly Views for the past 3 years
Plum Analytics
Actions (login required)
 |
View Item |
![[feed]](/images/feed-icon-32x32.png){kind=icon}