No evidence for effects of a high-frequency repetitive transcranial magnetic stimulation series on verbal and figural fluency and TAP task performance in healthy male volunteers.

BACKGROUND Study results on cognitive effects of repetitive transcranial magnetic stimulation (rTMS) in healthy people are inconsistent. Moreover, former trials performed exclusively single-session stimulations. This sham-controlled study analyzed the influence of 9 serial high-frequency rTMS on cognition. METHODS 44 young healthy male volunteers received active or sham rTMS. We evaluated verbal fluency tasks, the Ruff Figural Fluency Test and different Test for Attentional Performance tasks (alertness, go/no-go, divided attention, working memory, flexibility) prior to the first stimulation, immediately (within 5-30 min) after stimulation on day 5 and on day 10 (1 day after the last stimulation). RESULTS Overall, our statistical analyses revealed no significant cognitive effects of serial rTMS. CONCLUSION In this sham-controlled study design, 9 serial rTMS over the left dorsolateral prefrontal cortex (targeted by the 5-cm rule) did neither enhance nor impair the assessed cognitive functions in healthy male volunteers.