Effects of intermittent theta burst stimulation on spasticity in patients with multiple sclerosis

Background and purpose: Spasticity is a common disorder and a major cause of long-term disability in patients with multiple sclerosis (MS). Our aim was to evaluate whether a recently developed repetitive transcranial magnetic stimulation protocol, the intermittent theta burst stimulation (iTBS) is effective in modulating lower limb spasticity in MS patients. Methods: Twenty MS patients were pseudorandomized to undergo a 2-week daily sessions of real or sham iTBS protocol. The H/M amplitude ratio of the Soleus H reflex, a reliable neurophysiological index of spinal excitability and the Modified Ashworth Scale (MAS) for spasticity were evaluated by blinded raters before and after the stimulation protocols. Results: Patients receiving real iTBS showed a significant reduction of H/M amplitude ratio and MAS scores 1 week after the stimulation and persisting up to 2 weeks after the end of stimulation protocol. There were no significant effects for sham stimulation. Conclusions: These results show that iTBS, a safe, non-invasive, well-tolerated and feasible protocol, is a promising tool for the treatment of spasticity in MS.