Effects of Intermittent Theta Burst Stimulation on Manual Dexterity and Motor Imagery in Patients with Multiple Sclerosis: A Quasi-Experimental Controlled Study

Background: Intermittent theta burst stimulation (iTBS) is a repetitive transcranial magnetic stimulation (rTMS) protocol that influences cortical excitability and motor function recovery. Objectives: This study aimed to investigate the effects of iTBS on manual dexterity and hand motor imagery in multiple sclerosis (MS) patients. Methods: Thirty-six MS patients were non-randomly assigned into sham (control) or iTBS groups. Then, iTBS was delivered to the primary motor cortex for ten days over two consecutive weeks. The patients' manual dexterity was assessed using the nine-hole peg test (9HPT) and the Box and Block Test (BBT), while the hand motor imagery was assessed with the hand mental rotation task (HMRT). Results: iTBS group showed a reduction in the time required to complete the 9HPT (mean difference = -3.05, P = 0.002), and an increase in the number of blocks transferred in one minute in the BBT (mean difference = 8.9, P = 0.001) when compared to the control group. Furthermore, there was no significant difference between the two groups in terms of the reaction time (P = 0.761) and response accuracy rate (P = 0.482) in the HMRT. Conclusions: When iTBS was applied over the primary motor cortex, it significantly improved manual dexterity, but had no significant effect on the hand motor imagery ability in MS patients.