- Identify the hypothesis they are testing in the study. The hypothesis may not be explicitly outlined. If not, write a suitable hypothesis for the study
- Give a brief explanation of why this study was carried out and why the research is important.
Cerebral palsy is a group of permanent, irreversible motor conditions that cause impaired body movement. Surgeon is used to improve limb function. Clinical examination and observational gait analysis that are used for assessing the degree of abnormality are subject to error. Therefore, systematic and instrumented gait analysis is needed and important to the selection of therapeutic treatments.
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Several previous studies was focused on the gait velocity, ground reaction force, and ability to change stride length and walking speed, while the study of the repeatability of kinematic and kinetic data has not been reported (Steinwender, et. al., 2000). This study has filled the gap.
- In a brief synopsis, describe the experimental procedure, so we can understand what they did and how they achieved the results.
Forty children were included in this study, 20 with cerebral palsy and 20 normal children. The normal children had no previous history of any musculoskeletal problems. To monitor the body motion of these children, markers (sensors) were attached to certain cites in their bodies, including heel, lateral malleolus, between the second and third metatarsal heads, lateral femoral condyle, lateral aspect of the greater trochanter, anterior superior iliac spine, sacrum, and the acromion (Steinwender, et. al., 2000).
The children were asked to walk at a self-selected speed for several trials. The kinematic data of their walking motion, including the pelvis, hip, knee and ankle angles, was recorded by a floor-mounted force-plate (Steinwender, et. al., 2000). The kinetic data was recorded by a six-camera video based motion capturing system. Time-distance parameters, including stride length, cadence, and gait velocity, were determined using the kinematic data (Steinwender, et. al., 2000). The repeatability of time-distance parameters was defined by coefficient of variation (CV), the ratio of the standard deviation to the mean value of time-distance parameters (Steinwender, et. al., 2000). The repeatability of kinematic and kinetic parameters was defined as the coefficient of multiple correlation (CMC), the positive square root of the adjusted coefficient of multiple determination (Steinwender, et. al., 2000).
- What are the main findings in the results? Has the work been able to successfully test the hypothesis?
The spastic and normal children both showed more variability in walking velocity than in cadence and stride length (Steinwender, et. al., 2000). In the normal group, a negative correlation was found between the cadence and the stride length, while such a correlation did not exist in spastic children (Steinwender, et. al., 2000). Both the groups demonstrated lower variability in a lower joint range of motion compared to the average joint range of motion (Steinwender, et. al., 2000). The total limb moment was found to show a significantly higher variability in the spastic children than in the normal children (Steinwender, et. al., 2000). The spastic group had more variations (repeatability) in the joint moments within days, while the normal group did it between days (Steinwender, et. al., 2000). As this study was investigating the differences in the gait movement between spastic and normal children, the findings has been able to successfully support the hypothesis that the repeatability of gait kinematic and kinetic variables is different in normal and cerebral palsied children.
- What is the key conclusion of the paper – your own feeling on the main finding/relevance of the work?
Children with cerebral palsy have a less repeatable gait pattern than normal children due to the former’s inability to vary individual joint moments.
- If you were to carry on with this work, based on what you’ve read and your general medical engineering knowledge can you think of an interesting study you would like to do next?
Because muscle weakness has been proposed as a cause of crouch gait in cerebral palsy patients (Steele, et. al., 2012), I would combine three-dimensional gait analysis with muscle strength tests. I would use a dynamometer to measure isometric strength of the leg muscles, following the procedures reported before (Dallmeijer, et. al., 2011). I would then compare the muscle strength between spastic and normal children and figure out whether there is a correlation between muscle strength and joint moments.
Reference
- Steinwender, G. Saraph, V. Scheiber, S. Zwick, E. B. Uitz, C. and Hackl, K., 2000. Intrasubjective repeatability of gait analysis data in normal and spastic children. Clinical Biomechanics, 15, pp.134-139.
- Steele, K. M. van der Krogt, M. M. Schwartz, M. H. Delp, S. L., 2012. How much muscle strength is required to walk in a crouch gait? Journal of Biomechnics, 45(15), pp.2564-2569.
- Dallmeijer, A. J. Baker, R. Dodd, K. J. and Taylor, N. F., 2011. Association between isometric muscle strength and gait joint kinetics in adolescents and young adults with cerebral palsy. Gait & Posture, 33(3), pp.326-332.
