Impact of Seasonal Variations on Spasticity Assessment and Treatment

Abstract

BACKGROUND: Spasticity is treated using intramuscular botulinum toxin injections. Previous reports of worsening of spasticity in cold weather suggest that spasticity levels and botulinum toxin dose may both be influenced by seasonal temperature changes. AIMI: The aim of this study was to determine the effect of seasonal temperature variation on spasticity and botulinum toxin dosage. METHODS: Medical charts of 132 participants in 3 diagnostic groups: (1) stroke (n=60); (2) multiple sclerosis (n=34); and (3) cerebral palsy (n=38) receiving treatment in an outpatient spasticity clinic were reviewed. Age, sex, diagnosis, number of muscles injected, botulinum toxin dose, and spasticity (Modified Ashworth Scale) were collected for summer and winter. Spasticity and botulinum toxin dose were compared between summer and winter using separate paired t-tests for each diagnostic group. RESULTS: The spasticity level, botulinum toxin dosage, and total number of muscles in summer versus winter months were not significantly different (p>0.05) in any diagnostic group. Conclusions: Seasonal temperature variations appear to have no effect on spasticity or botulinum toxin dosage. Performance of spasticity measurements in warm indoor environment may have negated the impact of seasonal temperature differences. Future studies should perform spasticity measurements in temperature controlled rooms to mimic seasonal variations.