Repetitive transcranial magnetic stimulation effects on language function depend on the stimulation parameters

In previous studies it has been shown that picture-naming latencies can be facilitated with both suprathreshold single and repetitive transcranial mag netic stimulation (TMS/rTMS) over Wernicke's area. The aim of this study wa s to investigate whether low-frequency rTMS (1 Hz) or high-frequency rTMS ( 20 Hz) at subthreshold intensities is also capable of influencing picture n aming. In 16 healthy right-hand male subjects, trains of I Hz or 20 Hz were applied over either Wernicke's area, Broca's area, or the primary visual c ortex. The subjects had to name 20 black-and-white line drawings, which wer e shown immediately after rTMS and again 2 minutes later. Naming latency co uld be facilitated only immediately after Wernicke's area stimulation at a frequency of 20 Hz and at an intensity of 55% of the maximal stimulator out put, which was more than the motor threshold. All other stimulation procedu res failed to influence naming latencies. These results indicate that langu age functions can be facilitated in healthy subjects only by high-frequency rTMS with intensities at or above the motor threshold.