The Immediate Effects of Intermittent Theta Burst Stimulation of the Cerebellar Vermis on Cerebral Cortical Excitability During a Balance Task in Healthy Individuals: A Pilot Study

Abstract

<b>Objective:</b> This pilot study aimed to investigate the immediate effects of single-session intermittent theta-burst stimulation (iTBS) on the cerebellar vermis during a balance task, which could unveil the changes of cerebral cortical excitability in healthy individuals. <b>Subjects:</b> A total of seven right-handed healthy subjects (26.86 ± 5.30 years) were included in this study. <b>Interventions:</b> Each subject received single-session iTBS on cerebellar vermis in a sitting position. <b>Main Measures:</b> Before and after the intervention, all subjects were asked to repeat the balance task of standing on the left leg three times. Each task consisted of 15 s of standing and 20 s of resting. Real-time changes in cerebral cortex oxygen concentrations were monitored with functional near-infrared spectroscopy (fNIRS). During the task, changes in blood oxygen concentration were recorded and converted into the mean HbO₂ for statistical analysis. <b>Results:</b> After stimulation, the mean HbO₂ in the left SMA (<i>P</i> = 0.029) and right SMA (<i>P</i> = 0.043) significantly increased compared with baseline. However, no significant changes of mean HbO₂ were found in the bilateral dorsolateral prefrontal lobe (<i>P</i> > 0.05). <b>Conclusion:</b> Single-session iTBS on the cerebellar vermis in healthy adults can increase the excitability of the cerebral cortex in the bilateral supplementary motor areas during balance tasks. <b>Clinical Trial Registration:</b> [www.ClinicalTrials.gov], identifier [ChiCTR2100048915].