Examining the feasibility and tolerability of a clinically informed multisite, repetitive transcranial magnetic stimulation protocol

BACKGROUND: Multi-site repetitive transcranial magnetic stimulation (rTMS) has been applied experimentally in the treatment of obsessive compulsive disorder (OCD). NEW METHOD: This study was conducted to systematically evaluate the safety, tolerability and neurocognitive effects of rTMS applied to three cortical regions over a period of three months. NEW METHOD: Twenty healthy participants aged 22-33 years were randomly allocated to receive one session of active or sham stimulation of low and high frequency rTMS applied sequentially to the pre-supplementary motor area, right-dorsolateral prefrontal cortex and left-orbitofrontal cortex totalling 9min. Tolerability and safety was evaluated using a standardised safety questionnaire. Neurocognitive functioning was examined using the Cambridge Neuropsychological Test Automated Battery and measures of verbal fluency from the Delis-Kaplan Executive Functioning Test™ at five time points over three months. RESULTS: The protocol was safe and tolerable. Frequencies of minor adverse effects were higher in active (17 endorsements) than sham (1 endorsement) conditions. No between group differences in neurocognitive functioning were identified over three months. COMPARISON WITH EXISTING METHOD: This study is the first to evaluate the feasibility of low and high frequency parameters applied sequentially in a single session to the three selected cortical regions whilst providing neurocognitive data. CONCLUSIONS: rTMS applied sequentially over three cortical regions was found to be safe and tolerable in healthy individuals with no major neurocognitive effects over three months. Such findings can be used to inform the development of rTMS protocols involving multi-site stimulation for OCD.