ABSTRACT
Transcranial magnetic stimulation (TMS) can noninvasively, and relatively painlessly, focally stimulate the brain of awake individuals.1 When TMS pulses are delivered in a periodic repeating pattern, it is referred to as repetitive TMS, or rTMS. rTMS is sometimes modied by the adjectives “fast,” to describe stimulation frequencies greater than 1 Hz, or “slow,” for frequencies of 1 Hz or less.2 Fast rTMS is currently limited to very brief runs of about 25-30 Hz, although some
machines can now reach 50 Hz for brief bursts. Stimulation frequencies faster than this have an increased seizure risk and most modern capacitors cannot keep delivering the needed energy before depleting.3
