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Title: Muscle impairment in cerebral palsy : does the current 'standard' method of simulating muscle activations during human walking produce valid results?
Author: Lewis, Andrew Peter
ISNI:       0000 0004 5921 2008
Awarding Body: King's College London
Current Institution: King's College London (University of London)
Date of Award: 2015
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It has been proposed that musculo-skeletal modelling techniques may provide new tools for use in clinical gait analysis to help our understanding of the role of muscles and tendons in movement dysfunction. Sensitivity and validity analyses are necessary and important steps in achieving this goal. The aim of this investigation was to evaluate SimTrack, a workflow for generating muscle driven simulations of movement embedded within the 3D musculo-skeletal modelling software package OpenSim (Delp et al., 2007). Walking in both pathological (cerebral palsy) and typically developing subjects was analysed. If muscle activations can be accurately determined using such techniques, advanced simulation methods may be used to determine the mechanical potential of muscles in these groups and therefore help identify muscles in subjects with cerebral palsy that cannot make significant contribution to support and progression in walking. Ten typically developing adolescents and ten independently ambulant adolescents with cerebral palsy were recruited and the following data collected: MRI of the lower-limbs; 2D-ultrasound of a number of lower limb muscles; 3D motion, electromyography and ground-reaction-force data of the subjects’ walking patterns. The muscle morphology of subjects in the two groups were assessed and this data was used to inform 3D musculo-skeletal models. Each model’s muscle activations were allowed to vary to track the subject’s recorded walking pattern and the sensitivities of these simulated activations to changes in model muscle strength were tested over a normative range. The validity of the simulated activations were then determined by comparison with experimental electromyographic data. In the case group, muscle volumes were found to be smaller (principally in the distal musculature) and physiological cross-sectional areas were found to be larger in the thigh and smaller in the shank than the control group. The musculo-skeletal model was insensitive to changes in muscle strength. All simulated activations were found to be invalid. The results suggest that the application of SimTrack to the understanding of normal and pathological gait may be compromised by an inability to generate valid muscle activations.
Supervisor: Shortland, Adam ; Keevil, Stephen Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available