Sensorimotor control of walking balance in individuals with and without cerebral palsy
Date
2023
Authors
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Publisher
University of Delaware
Abstract
Individuals with cerebral palsy (CP) are at a high risk of falling, with about 35% reporting daily falls. Falls can occur because of problems in either sensing the motion of the body in space, or in generating an appropriate motor response to the perceived motion. Individuals with CP have well-documented deficits in processing and integrating sensory input, which can play a significant role in balance control. However, the current standard of care for balance problems in CP largely focuses on motor deficits, with limited consideration of sensory impairments. Thus, there is a critical need to investigate the role of sensory processing in balance control in individuals with CP. The overarching goal of this dissertation was to investigate how individuals with CP use sensory information, particularly vision, to control walking balance and whether augmenting their sensory input, specifically, proprioception, can improve their walking balance. ☐ Proprioceptive deficits in individuals with CP are associated with higher reliance on visual feedback to control standing balance. It is not well understood how individuals with CP use visual information for sensorimotor feedback control of balance during walking. In Aim 1, we used visual perturbations to understand how individuals with and without CP integrate visual input for walking balance control. We found that compared to their typically developing (TD) peers, the overall body sway in response to the visual perturbations was magnified and delayed in CP group, implying that they were more affected by changes in visual cues and relied more so on visual information for walking balance control. Also, the CP group showed a dominant proximal foot placement strategy and diminished ankle roll response, suggestive of a reliance on proximal over distal control of walking balance in individuals with CP. ☐ In Aim 2, we investigated the immediate effects of augmenting proprioception through the application of a sensory-centric intervention, such as stochastic resonance (SR) stimulation, on walking balance in individuals with CP and TD. We found that SR application resulted in a small but significant increase in lateral and anterior margin of stability. This implies that with SR, a larger impulse was needed to become unstable. This suggests that SR stimulation, which is known to enhance proprioception, may have improved the CP group’s awareness of body motion during walking. ☐ Lastly, it is not known if visual reliance can be reduced by providing SR stimulation to increase the acuity of proprioceptive feedback. Thus, by upweighting the proprioceptive input, SR can potentially reduce the reliance on visual input for balance control, freeing visual information for high-level tasks like navigation and obstacle avoidance. In Aim 3, we investigated if SR stimulation results in reduced reliance on vision during visually perturbed walking in individuals with CP and TD. We found that the response to visual perturbations was significantly smaller with SR in the CP group, while the TD group did not show any significant change with versus without SR. We propose that SR, by enhancing proprioception, may have led to upweighting of proprioception and downweighing of visual input, leading to a reduced reliance on vision for walking balance control. ☐ Overall, the findings from this dissertation will aid in development of a sensory-based treatment approach and will be a critical addition to the current motor-centric treatments, thus providing a more comprehensive approach to balance rehabilitation in CP.
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Keywords
Sensorimotor control, Walking balance, Cerebral palsy, Proximal foot placement, Proprioception