Force production and control in children with cerebral palsy
Children with cerebral palsy (CP) have an injury to the immature central nervous system that causes a variety of motor deficits resulting in limited mobility, thereby hindering intellectual and social stimulation. The long-term goal of this research is to develop practical and effective therapeutic interventions to increase mobility in children with CP, ultimately enhancing their independence and quality of life. To that end, contributions of this research include the design of a novel isometric experimental system with visual biofeedback to analyze lower extremity force production and control, the assessment of motor capabilities in able-bodied children and children with CP, and the development and implementation of a submaximal force control training paradigm for children with CP.
Motor control assessments in able-bodied children and children with CP included lower extremity force production and submaximal control and postural control. During maximum voluntary contractions, children with CP demonstrated significant alterations to the temporal characteristics of their joint moment profiles and abnormal multi-joint coordination strategies. A submaximal joint moment control task without visual biofeedback revealed that children with CP were unable to produce distinct dorsiflexion contractions. However, when provided with visual biofeedback and a joint moment target, they were able to match target levels as well as able-bodied children, but demonstrated difficulties while moving to the target. During a more complex, endpoint force target acquisition paradigm, children with CP never entered half of the presented targets. The joint moment magnitudes required during this task were no different than those used during the joint moment control task; however, endpoint force targets required simultaneous coordination of the hip, knee, and ankle. A self-initiated weight shift task (dynamic postural control) also revealed deficits in children with CP in that they achieved fewer targets and had decreased movement velocities compared to able-bodied children. Finally, the submaximal force control training paradigm, implemented in a small sample of children with CP, resulted in improved joint moment and endpoint force control, but limited changes in force production and postural control. Collectively, this research characterized neuromotor deficits in children with CP and suggested therapeutic strategies that may promote improved neuromotor control.
0541: Biomedical engineering