AUTHOR=Yu Fengyun , Tang Xinwei , Hu Ruiping , Liang Sijie , Wang Weining , Tian Shan , Wu Yi , Yuan Ti-Fei , Zhu Yulian 

TITLE=The After-Effect of Accelerated Intermittent Theta Burst Stimulation at Different Session Intervals

JOURNAL=Frontiers in Neuroscience

VOLUME=Volume 14 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2020.00576

DOI=10.3389/fnins.2020.00576

ISSN=1662-453X

ABSTRACT=Objective: The study aims to investigate the after-effect of 3 sessions of intermittent theta bursts (iTBS) on mototr cortical excitability. The iTBS was induced over the primary motor cortex (M1) at different time intervals.

Methods: The study has a cross-over design. Sixteen participants were assigned to 3 groups and received different accelerated iTBS protocols during each visit: (1) 3 continuous sessions with no interval (iTBS18000); (2) 3 iTBS sessions with 10 minutes intervals (iTBS600×3*10); (3) 3 iTBS sessions with 30 minutes intervals (iTBS600×3*30). As washout period, each visit is separated by at least 7 days. We measured the motor cortical excitability changes and intracortical inhibition. 

Results: A dose of 1800 pulses of accelerated iTBS per day is tolerable. The iTBS1800 led to a reduced cortical excitability; while iTBS600×3*10 and iTBS600×3*30 enhanced cortical excitability to a differential extent. After a total dose of 1800 pulses, iTBS600×3*30 exhibited the longer effect and highest percentage of individuals with enhanced cortical excitability. 

Conclusions: The results suggest that accelerated iTBS protocols at different time intervals result in different motor cortical excitability after-effects.