Brief report: Preliminary study on evaluation of spasticity in patients with brain lesions using mechanomyography

Background: Electromyography and the modified Ashworth scale (MAS) are among the most effective methods for evaluating spasticity; however, these are often inappropriate for clinical use, owing to the complicated procedure and subjective evaluation outcomes. Methods: A passive stretch reflex test was performed on 10 subjects with brain lesions. Furthermore, mechanomyography and electromyography were conducted on the vastus lateralis muscle (agonist) and semitendinosus muscle (antagonist) of the subjects with brain lesions. A new equation to define the normalized hull area; that is, the mechanomyography (MMG) ratio, was applied to quantify the triaxial motion of the agonist muscle versus antagonist muscles, reflecting the electromyographic firing point of the spastic muscle. Findings: The MMG ratio was proposed, which statistically distinguishes the spastic and normal muscles (p = 0.01) and exhibits a concordance with the conventional mean MAS (r = 0.69, p = 0.01). Interpretation: Patients suspected to have spasticity of 0 to 1+ grade can be quantitatively evaluated using the normalized hull area ratio, which can be used as an additional clinical indicator for spasticity evaluation. Registration of clinical trials: The study was conducted in conformity with the Helsinki declaration principles and performed in the Korea Centers for Disease Control and Prevention, Ministry of Health and Welfare (Republic of Korea); 2010; KCT0002385; A new approach of spasticity measurement using mechanomyography in patients with brain lesions: A randomized pilot study for a parallel randomized controlled trial; October 8, 2015 [Cited on July 21, 2017]; [1 screen]. Available from: https://cris.nih.go.kr/cris/search/search_result_st01_en.jsp?seq=7805&ltype=&rtype=.