Development and clinical application of assessment measures to describe and quantify intra-limb coordination during walking in normal children and children with cerebral palsy

A thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the degree of Doctor of PhilosophyThis thesis investigates coordination of the lower limb joints within the limb during walking. The researcher was motivated by her clinical experience as a paediatric physiotherapist. She observed that the pattern of lower limb coordination differed between normal children and those with cerebral palsy. Many of the currently used interventions did not appear to influence this patterning. As a precursor to evaluating the effectiveness of treatments in modifying coordination, a tool to measure coordination was required. The researcher initially investigated qualitative and then quantitative methods of measuring within limb coordination. A technique was developed that used relative angular velocity of two joints to determine when joints were in-phase, antiphasic or in stasis. The phasic parameters of hip/knee, knee/ankle and hip/ankle joints coordination were quantified. There were some significant differences between normal children and children with cerebral palsy. Asymmetry of these phasic parameters was identified, with children with cerebral palsy being more asymmetrical than normal children. The clinical utility of this technique was tested by comparing 2 groups of children before and after 2 surgical procedures. This showed some significant differences in phasic parameters between pre and post-operative data for one procedure. Low samples sizes mean that further work is required to confirm these findings. Data from this work has been used to calculate sample sizes to give an a priori power of 0.8 and further research is proposed and potential applications discussed. It is hoped that this technique will raise awareness of abnormal intra-limb coordination and allow therapists to identify key interactions between joints that need to be facilitated during walking training

Feasibility of Muscle Synergy Outcomes in Clinics, Robotics, and Sports: A Systematic Review

In the last years, several studies have been focused on understanding how the central nervous system controls muscles to perform a specific motor task. Although it still remains an open question, muscle synergies have come to be an appealing theory to explain the modular organization of the central nervous system. Even though the neural encoding of muscle synergies remains controversial, a large number of papers demonstrated that muscle synergies are robust across different tested conditions, which are within a day, between days, within a single subject and between subjects that have similar demographic characteristics. Thus, muscle synergy theory has been largely used in several research fields, such as clinics, robotics and sports. The present systematical review aims at providing an overview on the applications of muscle synergy theory in clinics, robotics and sports; in particular, the review is focused on the papers that provide tangible information for: (i) diagnosis or pathology assessment in clinics; (ii) robot-control design in robotics; and (iii) athletes’ performance assessment or training guidelines in sports

DETERMINING SELECTIVE VOLUNTARY MOTOR CONTROL OF THE LOWER EXTREMITY IN CHILDREN WITH CEREBRAL PALSY

For physiotherapists working in neuro-paediatric gait-rehabilitation, improving motor control of the lower extremity is a major focus. Nevertheless, our understanding of selective voluntary motor control (SVMC) is in its infancy. This PhD project aimed to contribute to close this gap by investigating the nature of SVMC of the lower extremity in children with cerebral palsy (CP) and providing a psychometric robust yet sensitive measurement instrument for quantifying SVMC. The first study investigated the influence of SVMC and other lower extremity and trunk motor impairments on gait capacity using multiple regression-analyses. Although SVMC was not kept within the final model, these study results revealed the importance of SVMC in relation to muscle strength, trunk control and gait capacity. The aim of the second study was to establish validity and reliability of the German version of the ‘Selective Control Assessment of the Lower Extremity’ (SCALE). Although the psychometric properties of the German SCALE were good, information about its responsiveness is lacking. Accordingly, a systematic review was carried out to identify a SVMC measurement instrument with the highest level of evidence for its psychometric properties and best clinical utility. As the findings showed the absence of appropriate, responsive SVMC measures, the aim of the last study was to modify the existing SCALE to make it more sensitive. Due to the positive findings in relation to the psychometric properties of the SCALE, its procedure was combined with a surface electromyography Similarity Index (SI). The first validity and reliability results of the SCALE-SI are promising and serve as benchmarks when applying the SCALE-SI in future clinical and scientific practice. However, to use the SCALE-SI as an outcome measure for detecting therapy-induced changes of SVMC in children with CP, its responsiveness needs to be evaluated in future studies. Key Words: cerebral palsy, selective voluntary motor control, psychometric properties, lower extremity, gait rehabilitatio