P79-S Tolerability of repetitive transcranial magnetic stimulation: Analysis of 727 sessions with standardized questionnaires

Background Repetitive transcranial magnetic stimulation (rTMS) is used in both clinical practice and basic research. The aim of our study was to investigate rTMS tolerability using standardized questionnaires. Materials and methods 69 patients (vascular mild cognitive impairment – 36, recurrent depression – 13, post-stroke pain – 8, trigeminal neuralgia – 8, multiple sclerosis – 4) and 12 healthy volunteers were included. Participants received high-frequency rTMS (10 or 20 Hz) over dorsolateral prefrontal cortex (DLPFC, n  = 42), primary motor cortex ( n  = 20), supplementary motor area ( n  = 6) and vertex ( n  = 21). Standardized questionnaires were obtained to assess adverse effects (AEs) during the procedure and within 24 h after. Results 727 sessions were analyzed. The rate of AEs was 56.0% during rTMS and 24.7% within 24 h after procedure. Treatment cessation due to AEs was registered in 3.6% of cases (1 syncope and 2 cases of severe headache). The most common AEs during rTMS included drowsiness (29.9%), headache (22.3%) and contractions of face muscles (13.5%); within 24 h - headache (15.8%), mood changes (8.9%) and concentration difficulties (7.7%). Headache during rTMS was predominantly low intensive (62.9%) and pulsatile (35.2%); after stimulation - moderate intensive (55.3%), pressing (54.4%), developed within 30 min (40.8%) and continued more than 4 h (47.6%). Headache occurred significantly more often during rTMS over DLPFC than other areas ( p Conclusions Mild AEs are common during rTMS and within 24 h, while severe AEs occur rarely. We have also shown distinctive characteristics of headache during and after rTMS, suggesting different underlying mechanisms.