1316 - Correlation of Spastic Muscle Echointensity and EMG Activity in Stroke Survivors

This pilot study involved 16 chronic stroke patients ( >6-month post stroke) with spastic hemiparesis as defined by Modified Ashworth Scale of >1+ in upper and/or lower extremity (elbow flexors, wrist/finger flexors, hip adductors, knee extensors, and/or plantar flexors).   Five muscles were examined via ultrasound (brachialis, flexor carpi radialis (FCR), rectus femoris, gracilis, and medial gastrocnemius). MUE was assessed by the Heckmatt scale using a 1-4 numerical scale (1 normal-4 very strong echogenicity). EMG activity was recorded using a novel four point scale  based on EMG activity at rest and response to passive stretch.

Results: Brachialis (n=8), FCR (n=7), gracilis (n=4), and medial gastric (n=10) were analyzed.  The rectus femoris was omitted from analysis due to small sample size (n=2). Spearman correlations coefficients (r) were calculated to quantify relationships between MUE and EMG activity separately for each muscle. Statistically significant (p< 0.05) correlations were found for the brachialis (r=-0.690, p=0.029) and FCR (r=-.760, p=0.025) muscles.

Conclusions: This pilot study did not find the expected negative correlation between EMG activity and MUE in all muscles. This suggests that using both techniques together may be more effective than either alone for BoNT dose titration.  An additional study is needed to clarify their relationship and impact on administrating BoNT for post stroke spasticity.