Repetitive transcranial magnetic stimulation in murine models of epilepsy: A systematic review of methodological aspects and outcomes.

Objectives: Clinical studies of repetitive transcranial magnetic stimulation (rTMS) do not provide consistent efficacy results, possibly due to variability in methodological parameters. Our aim is to systematically review preclinical rTMS protocols in murine models of epilepsy, offering insights from might facilitate the optimization of clinical trials.

Methods: We searched MEDLINE, SCOPUS and Web of Science from inception until December 2023, including English-written and peer-reviewed studies with clinical or electroencephalographic (EEG) outcomes.

Results: Among 480 search results, in the 23 eligible studies both mice and rats were used. Epilepsy induction methods included injections of pentylenetetrazole, kainic acid, picrotoxin and lithium-pilocarpine, electrical kindling (amygdala/ventral hippocampus), electroconvulsive shock and genetic models of absence and temporal lobe epilepsy. For motor threshold (MT) definition electromyography with motor evoked potentials and single-pulse TMS were used. Stimulation intensity ranged between 40 % and 200 % of MT or 0.125-2.5 T. High-frequency rTMS (≥5 Hz) demonstrated either no effect on seizure suppression or a rather facilitatory effect, promoting ictogenesis, with the exception of 20-Hz-rTMS coupling with lorazepam for status epilepticus cessation. Low-frequency rTMS (<5 Hz), primarily at 0.5 and 1 Hz, exerted an inhibitory effect on both clinical and EEG parameters on various epilepsy models in most studies and also significantly ameliorated performance in behavioral tests.

Conclusions: rTMS holds potential for effective neuromodulation, that is critically dependent on stimulation frequency and epilepsy type. Translational knowledge gained from preclinical protocols may inform and optimize rTMS application for epilepsy management in future clinical trials.