Date of Award
Spring 2021
Document Type
Dissertation - Restricted
Degree Name
Doctor of Philosophy (PhD)
Department
Exercise Science
Program
Exercise and Rehabilitation Science
First Advisor
Hyngstrom, Allison S.
Second Advisor
Schmit, Brian D.
Third Advisor
Wang, Marjorie C.
Abstract
The purpose of this dissertation was to examine balance impairments in people with degenerative cervical myelopathy. We examined the reactive postural responses to mediolateral pulls to the waist under predictable/unpredictable conditions, the contribution of the size of the base of support on postural control, and across pull magnitudes. Assessing reactive balance affords us the ability to assess the person’s response to external perturbations that could cause falls in real life scenarios. Specifically, we quantified whole body motion of the center of mass excursion following pulls and the amplitudes and latencies of several muscles from the lower extremity. Additionally, we made comparisons with clinical measures of balance. In these series of studies, we observed that people with degenerative cervical myelopathy experience larger postural excursions following waist pulls both in standing and walking. In standing, these are associated with increased hip muscular latencies. In walking, people with degenerative cervical myelopathy additionally generate reduced amplitude muscle responses which are also delayed relative to non-myelopathic controls. In response to walking with repeated waist pulls, people with degenerative cervical myelopathy adapt center of mass motion and step width similarly to controls, however, they rely on a more ankle dominant strategy to accomplish this. Together these results suggest that people with degenerative cervical myelopathy would benefit from balance training, strengthening, and training in more powerful responses particularly of the hip musculature. Clinical measures of balance were related to reactive balance in standing. Measures of myelopathic severity, however, were more strongly associated with gait speed, clinical measures of balance during walking with predictable perturbations, and reactive balance during walking with predictable perturbations. This suggests that function of reactive balance per se is underappreciated in current clinical assessments.