Reproducibility of TMS-Evoked EEG responses.

Abstract: Navigated transcranial magnetic stimulation combined with electroencephalography (nTMS-EEG), allows noninvasive studies of cortical excitability and connectivity in humans. We investigatedthe reproducibility of nTMS-EEG in seven healthy subjects by repeating left motor and prefrontalcortical stimulation with a 1-week interval. TMS was applied at three intensities: 90, 100, and 110% ofsubjects’ motor threshold (MT). The TMS-compatible neuronavigation system guaranteed preciserepositioning of the stimulation coil. The responses were recorded by a 60-channel whole head TMS-compatible EEG amplifier. A high overall reproducibility (r > 0.80) was evident in nTMS-EEGresponses over both hemispheres for both motor and prefrontal cortical stimulation. The results suggestthat nTMS-EEG is a reliable tool for studies investigating cortical excitability changes in the test-retestdesigns. Hum Brain Mapp 30:1387–1396, 2009. VV C 2008 W iley- L iss, I nc. Key words: electroencephalography; motor cortex; prefrontal cortex; reproducibility; transcranialmagnetic stimulation