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Similar effect of intermittent theta burst and sham stimulation on corticospinal excitability: A 5‐day repeated sessions study
Author(s) -
PerellónAlfonso Ruben,
Kralik Magdalena,
Pileckyte Indre,
Princic Matic,
Bon Jurij,
Matzhold Caspar,
Fischer Benjamin,
Šlahorová Petra,
Pirtošek Zvezdan,
Rothwell John,
Kojovic Maja
Publication year - 2018
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.14077
Subject(s) - transcranial magnetic stimulation , stimulation , motor cortex , psychology , primary motor cortex , brain stimulation , neuroscience , evoked potential , medicine , anesthesia
Despite accumulating evidence of inter and intraindividual variability in response to theta burst stimulation, it is widely believed that in therapeutic applications, repeated sessions can have a “build‐up” effect that increases the response over and above that seen in a single session. However, strong evidence for this is lacking. Therefore, we examined whether daily administration of intermittent theta burst stimulation ( iTBS ) over the primary motor cortex induces cumulative changes in transcranial magnetic stimulation measures of cortical excitability, above the changes induced by sham stimulation. Over five consecutive days, 20 healthy participants received either active iTBS or sham stimulation. Each day, baseline measures of cortical excitability were assessed before and up to 30 min after the intervention. There was no significant difference in the rate of response between iTBS and sham stimulation on any of the 5 days. There was no iTBS specific cumulative increase of corticospinal excitability. The likelihood that an individual would remain a responder from day‐to‐day was low in both groups, implying high within‐subject variability of both active and sham iTBS after‐effects. In contrast, we found a high within‐subject repeatability of resting and active motor threshold, and baseline motor‐evoked potential amplitude. In summary, sham stimulation has similar effect to active iTBS on corticospinal excitability, even when applied repeatedly for 5 days. Our results might be relevant to research and clinical applications of theta burst stimulation protocols.