Objective: To investigate the effect of repetitive transcranial magnetic stimulation (rTMS) applied over the left prefrontal cortex on the enhancement of verbal working memory in healthy persons. Method: High frequency (10 Hz) rTMS was applied over the left prefrontal cortex with the intensity of 100% resting motor threshold (RMT). A 3-back verbal working memory task was administered before, during (after applying 500 and 1,000 pulses, respectively), and 30 minutes after real or sham rTMS. Results: Real rTMS, compared with sham stimulation, significantly improved working memory performance. Accuracy of response increased significantly after applying 1,000 pulses of real rTMS (p＜0.05). This effect maintained for 30 minutes after completion of stimulation (p＜0.05). The error rate and reaction time did not change with rTMS. There was no noticeable side effect during or after rTMS. Conclusion: 1,000 pulses of 10 Hz rTMS administered to the left prefrontal cortex with the intensity of 100% RMT have positive impact on verbal working memory in healthy persons. Further study is necessary to address this effect of rTMS in patients with cognitive dysfunction. (J Korean Acad Rehab Med 2008; 32: 501-505)
