Transcranial and spinal cord magnetic stimulation in treatment of spasticity: a literature review and meta-analysis

Abstract

Spasticity is associated with various diseases of the nervous system. Current treatments such as drug therapy, botulinum toxin injections, kinesitherapy, and physiotherapy are not sufficiently effective in a large number of patients. Transcranial magnetic stimulation (TMS) can be considered as an alternative method of treatment. The purpose of this article was to conduct a systematic review and meta-analysis of all available publications assessing the efficacy of repetitive TMS in treatment of spasticity. Search for articles was conducted in databases PubMed, Willey, and Google. Keywords included "TMS", "spasticity", "TMS and spasticity", "non-invasive brain stimulation", and "non-invasive spinal cord stimulation". The difference in scores according to the Modified Ashworth Scale (MAS) for one joint before and after treatment was taken as the effect size. We found 26 articles that examined the TMS efficacy in treatment of spasticity. Meta-analysis included 6 trials comprising 149 patients who underwent real stimulation or simulation. No statistically significant difference in the effect of real and simulated stimulation was found in stroke patients. In patients with spinal cord injury and spasticity, the mean effect size value and the 95% confidence interval were -0.80 and (-1.12, -0.49), respectively, in a group of real stimulation; in the case of simulated stimulation, these parameters were 0.15 and (-0.30, -0.00), respectively. Statistically significant differences between groups of real stimulation and simulation were demonstrated for using high-frequency repetitive TMS or iTBS mode for the M1 area of the spastic leg (P=0.0002). According to the meta-analysis, the statistically significant effect of TMS in the form of reduced spasticity was demonstrated only for the developed due to lesions at the brain stem and spinal cord level. To clarify the amount of the antispasmodic effect of repetitive TMS at other lesion levels, in particular in patients with hemispheric stroke, further research is required.