Short-term memory: no evidence of effect of rapid-repetitive transcranial magnetic stimulation in healthy individuals.

The effect of rapid-repetitive transcranial magnetic stimulation (rr-TMS) on the immediate verbal and visuospatial memory span was assessed by computerized neuropsychological testing in 11 healthy volunteers. The objective was to test whether rr-TMS may be utilized as a non-invasive tool for evaluation of memory function. The subjects had to memorize series of numbers (Digit-Span test) or the position of cubes (Corsi-Block test) shown to them on a computer screen and actively reproduce them immediately after the presentation. Synchronous with the appearance of each item an rr-TMS train of 550 ms duration was delivered to the left or right anterolateral parietal as well as superior and posterior lateral temporal region at 50 Hz and with approximately 1.0 T stimulation intensity. Statistical comparison of memory performance during rr-TMS and baseline testings without stimulation revealed no significant changes. No adverse effects were observed. Thus, rr-TMS does not affect short-term memory performance in healthy individuals under the stimulation conditions described above.