A Frequency-based Electromyographic Index for Use in Cerebral Palsy

INTRODUCTION Surface electromyography (sEMG) is a typical part of instrumented gait assessment for the child with cerebral palsy (CP). Numerous methods exist to characterize the sEMG in order to gain insight into the neuromuscular impairments that exist in CP, including the use of muscle onset and offset and amplitude. However, these methods have focused upon one aspect of the sEMG to characterize the signal. The sEMG could potentially be better utilized clinically if multiple characteristics are examined concurrently. The introduction of timefrequency analysis provides a method of extracting more information from the sEMG in CP (Lauer et al 2005), and thus potentially gaining further insight into the neuromuscular system. The purpose of this study was to apply these techniques to the analysis of sEMG during gait in children with CP to derive an index that may be used to track and categorize muscle activity.