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Published on: July 19, 2013
Quantifying muscle coactivation in individuals with incomplete spinal cord injury using wavelets
Sabrina S M Lee1, Tania Lam2, Katherine Pauhl2
1Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada; Department of Physical Therapy and Human Movement Sciences, Northwestern University, 645 N Michigan Avenue, Chicago, IL, USA.
New electromyography analysis reveals frequency-specific differences in muscle coactivation in individuals with incomplete spinal cord injury. These patterns changed after body weight supported treadmill training, suggesting altered motor unit recruitment.
Area of Science:
- Neuroscience
- Biomechanics
- Rehabilitation Science
Background:
- Individuals with incomplete spinal cord injury (iSCI) often exhibit impaired gait and abnormal muscle coactivation.
- Traditional electromyography (EMG) analysis for coactivation overlooks crucial frequency information.
- Motor unit types have distinct frequency components, and muscle fiber characteristics can change post-iSCI, necessitating frequency-aware analysis.
Purpose of the Study:
- To evaluate a novel method for quantifying lower extremity muscle coactivation in iSCI using temporal and frequency EMG components.
- To compare coactivation patterns between individuals with iSCI and able-bodied controls.
- To assess changes in coactivation before and after body weight supported treadmill training in iSCI.
Main Methods:
- Applied frequency decomposition techniques to EMG signals to analyze temporal and frequency components of muscle coactivation.
- Quantified coactivation across a range of frequencies for lower extremity muscles.
- Compared coactivation metrics between iSCI and able-bodied groups and pre- vs. post-intervention.
Main Results:
- Significant differences in EMG intensity correlation coefficients between rectus femoris-biceps femoris and medial gastrocnemius-tibialis anterior were found between iSCI and able-bodied groups (p < 0.01).
- Correlation spectra for medial gastrocnemius-tibialis anterior differed substantially in the iSCI group compared to controls.
- An EMG normalcy score was significantly different (p = 0.002), and ankle muscle coactivation changed post-treadmill training.
Conclusions:
- Frequency-specific differences in muscle coactivation exist between individuals with iSCI and able-bodied individuals.
- Body weight supported treadmill training induced changes in muscle coactivation, particularly in ankle muscles.
- Observed differences likely reflect alterations in motor unit recruitment patterns following iSCI and rehabilitation.
