Interpretation of Gait Analysis Data by Means of Synthetic Descriptors and a New Method for the Analysis of the Offset

Abstract

This chapter illustrates the methods and the results of a research project about gait analysis (GA) data interpretation and pattern recognition on subjects with pathology. The chapter begins with a review of the most common synthetic descriptors and methods proposed and in use for the clinical interpretation of GA data. The use and development of synthetic descriptors for GA are encouraged by clinical practice, as a clinical GA exam often results in a long and complex clinical report containing a large number of parameters and curves. Thus, reading and understanding a GA clinical report is not an easy task and requires technical training and a long time. Reducing GA results to synthetic descriptors would make it easier for clinicians to understand the exam and identify walking impairments. The most relevant scientific works that used those methods on subjects with pathology are reviewed as well. In this work, the Gait Profile Score and a recently proposed index, the linear fit method, are implemented and applied to the GA exams of children with cerebral palsy (CP) in order to study gait variation pre- and post-surgical treatment. A novel index is designed, tested, and applied to those subjects as well. The new index, named Offset-Corrected Movement Analysis Profile, takes into account the effects due to offset and allows computing the deviation from normality on tracks purified by the offset. The results provide a detailed biomechanical analysis of the effects of surgical treatment on the walking pattern and the effectiveness of the indices in quantifying gait deviation. The linear fit method showed some limitations that make it unreliable for use with children with CP. Instead, the Offset-Corrected Movement Analysis Profile is able to identify the influence of offset on gait deviation and the direction (sign) of the deviation. Because, in this study, the offset was a significant component of deviation in gait pattern, the Offset-Corrected Movement Analysis Profile was demonstrated as being the most clinically meaningful synthetic method to interpret gait data in children with CP.