Transkranielle Magnetstimulation (TMS)- Einflussfaktoren auf die kortikale Erregbarkeit und Retest-Reliabilität der TMS

Transcranial magnetic stimulation (TMS) is a method to determine cortical excitability in humans. The latter is alterable by different influences and it is used in pharmacological studies to determine an effect profile, but also for therapeutic use. Different neurological diseases are accompanied by an altered cortical excitability. In epilepsy, several parameters of inhibition and excitation are altered according to the specific syndrome. The effect of anticonvulsants as a substance acting on the central nervous system to achieve seizure freedom has been studied previously. The included articles dealt with metabolic and genetic influences on the TMS measured cortical excitability as well as their retest-reliability, the quality of repeated measuring with TMS. The prospective study of patients with hypercalcaemia due to an endocrinological disease (primary hyperparathyroidism) could not proof an altered cortical excitability through changes in calcium after successful operation. In another study, we found, after intake of carbamazepine, in healthy participants with a polymorphism of the SCN1A gene, a differential influence on an inhibitory parameter. TMS can therefore contribute to clarify pharmacogenetic influences. The quality of measurements, a good reliability, has been objectively shown for most of the single- and double pulse paradigms in a thoroughly defined group of healthy participants with inclusion of women in the third study. TMS, as a non-invasive tool to measure cortical excitability, is robust and can be used in different fields, especially in combination with other methods as a valuable instrument in neurophysiological research.