SOURCE
Brain Stimulation. 13(5):1476-1488, 2020 Sep – Oct.
AUTHORS
Corp DT; Bereznicki HGK; Clark GM; Youssef GJ; Fried PJ; Jannati A; Davies CB; Gomes-Osman J; Stamm J; Chung SW; Bowe SJ; Rogasch NC; Fitzgerald PB; Koch G; Di Lazzaro V; Pascual-Leone A; Enticott PG
BACKGROUND
Many studies have attempted to identify the sources of interindividual variability in response to theta-burst stimulation (TBS). However, these studies have been limited by small sample sizes, leading to conflicting results.
OBJECTIVE/HYPOTHESIS
This study brought together over 60 TMS researchers to form the ‘Big TMS Data Collaboration’, and create the largest known sample of individual participant TBS data to date. The goal was to enable a more comprehensive evaluation of factors driving TBS response variability.
METHODS
118 corresponding authors of TMS studies were emailed and asked to provide deidentified individual TMS data. Mixed-effects regression investigated a range of individual and study level variables for their contribution to iTBS and cTBS response variability.
RESULTS
430 healthy participants’ TBS data was pooled across 22 studies (mean age = 41.9; range = 17-82; females = 217). Baseline MEP amplitude, age, target muscle, and time of day significantly predicted iTBS-induced plasticity. Baseline MEP amplitude and timepoint after TBS significantly predicted cTBS-induced plasticity.
CONCLUSIONS
This is the largest known study of interindividual variability in TBS. Our findings indicate that a significant portion of variability can be attributed to the methods used to measure the modulatory effects of TBS. We provide specific methodological recommendations in order to control and mitigate these sources of variability.
