An Exploration of the Underlying Mechanisms Causing Spasticity in Young People with Cerebral Palsy
Term of Award
Master of Science in Kinesiology (M.S.)
Document Type and Release Option
Thesis (open access)
Copyright Statement / License for Reuse
This work is licensed under a Creative Commons Attribution 4.0 License.
Department of Health and Kinesiology
Committee Member 1
Committee Member 2
Background and Objective(s): Spasticity is a common symptom experienced by individuals with cerebral palsy (CP). Spastic CP is often accompanied by hypertonia. Currently, there is a limited understanding of the contributions of spasticity to hypertonia which can in turn hinder the development of new rehabilitative measure to improve these conditions. Additionally, clinical evaluation of spasticity is limited to observational techniques such as the Ashworth scale. The purpose of this study was to compare differences in passive joint torque in the upper extremity between individuals with severe, spastic CP (MACS III-V) and healthy, age-matched controls at different speeds during passive stretching.
Study Participants & Setting: Six children (Mage = 15.0; SD =2.28) had been previously diagnosed with cerebral palsy, and the remaining six were age-matched controls (Mage =14.2; SD =1.32). The children with CP were classified as high CP (level III-V) based off the Manual Ability Classification System (MACS) scale.
Materials/Methods: Passive stretch torque during elbow flexion and extension were obtained using the Biodex (Biodex Medical Systems Incorporated, Shirley, NY) System 4 isokinetic dynamometer. Each participant went through five repetitions of passive stretch for both arms at four different speeds (90, 120, 150, and 180 deg/s). A comfortable range of motion was set for each participant and they were asked to stay relaxed throughout the entire testing period. Peak and average elbow passive torque due to extension (PTE / ATE) and flexion (PTF / ATF) movement during different stretching speeds were recorded as the outcome variables.
Results: This study observed significant PTF (group X velocity interaction, F(3, 15)= 4.60, p < .05), where the control group had increasing torque values as the velocity increased and the CP group had decreasing torque values as the velocity increased. Average torque during flexion significantly affected by passive stretching velocity in a linear fashion (p < .05) without group by speed interaction (p > .05). We also observed significant group X speed interaction (F(3, 15 )= 5.11, p < .05) for ATE, where both the control and participants with CP had increasing torque values as stretching velocity increased, but participants with CP had a greater increase. Peak torque during extension had no significant interactions to change of stretching velocity between the two groups of participants, but did display a significant linear trend by passive stretching velocity (p < .05).
Conclusions/Significance: Our observations indicate that young people with severe, spastic CP exhibit different joint torque values at different speeds. A more effective rehabilitation plan can be based off the observations in this study. More resistive torque occurred at slower stretching speeds for young people with lower upper extremity function and severe spasticity. For children at higher levels on the MACS, higher speeds appeared to provide less of a hypertonic response, which suggests that power training can be done at faster speeds in order to see improvements.
Carnes, Alexis, "An Exploration of the Underlying Mechanisms Causing Spasticity in Young People with Cerebral Palsy" (2017). Electronic Theses and Dissertations. 1612.
Research Data and Supplementary Material