Assessing the immediate impact of botulinum toxin injection on impedance of spastic muscle.
This study aimed to investigate the immediate impacts of Botulinum Toxin A (BoNT-A) injections on the inherent electrical properties of spastic muscles using a newly developed electrical impedance myography (EIM) technique. Impedance measures were performed before and after a BoNT-A injection in biceps brachii muscles of 14 subjects with spasticity. Three major impedance variables, resistance (R), reactance (X) and phase angle (θ) were obtained from three different configurations, and were evaluated using the conventional EIM frequency at 50kHz as well as multiple frequency analysis. Statistical analysis demonstrated a significant decrease of resistance in the injected muscles (Multiple-frequency: Rpre=25.17±1.94Ohm, Rpost=23.65±1.63Ohm, p<0.05; 50kHz: Rpre=29.06±2.16Ohm, Rpost=27.7±1.89Ohm, p<0.05). Despite this decrease, there were no substantial changes in the reactance, phase angle, or anisotropy features after a BoNT-A injection. The significant changes of muscle resistance were most likely associated with the liquid injection of the BoNT-A-saline solution rather than the immediate toxin effects on the muscle. This study demonstrated high sensitivity of the EIM technique in the detection of alterations to muscle composition.
Department of Physical Medicine and Rehabilitation, University of Texas Medical School at Houston, and TIRR Memorial Hermann Research Center, Houston, TX, USA . Electronic address: Xiaoyan.li@uth.tmc.edu.
Xiaoyan
X
Li
Department of Physical Medicine and Rehabilitation, University of Texas Medical School at Houston, and TIRR Memorial Hermann Research Center, Houston, TX, USA.
Henry
H
Shin
Department of Physical Medicine and Rehabilitation, University of Texas Medical School at Houston, and TIRR Memorial Hermann Research Center, Houston, TX, USA.
Le
L
Li
Department of Physical Medicine and Rehabilitation, University of Texas Medical School at Houston, and TIRR Memorial Hermann Research Center, Houston, TX, USA.
Elaine
E
Magat
Department of Physical Medicine and Rehabilitation, University of Texas Medical School at Houston, and TIRR Memorial Hermann Research Center, Houston, TX, USA.
Sheng
S
Li
Department of Physical Medicine and Rehabilitation, University of Texas Medical School at Houston, and TIRR Memorial Hermann Research Center, Houston, TX, USA ; Guangdong Work Injury Rehabilitation Center, Guangzhou, Guangdong Province, China.
Ping
P
Zhou
D000328:Adult; D000368:Aged; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage* / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D017097:Electric Impedance; D005260:Female; D006801:Humans; D007267:Injections; D008297:Male; D008875:Middle Aged; D009128:Muscle Spasticity / Q000503:physiopathology*; D009213:Myography
D019274:Botulinum Toxins, Type A
Botulinum Toxin A (BoNT-A); Electrical impedance myography (EIM); Spasticity