[Transcranial magnetic stimulation of patients with a single epileptic seizure]

Transcranial magnetic stimulation (TMS) was performed in 21 patients who had had loss of consciousness of unknown origin, in order to find out whether TMS could help in finding the cause of unconsciousness and to estimate the risk of provoking a seizure in patients who had single fits in the past. Furthermore, EEG recordings with hyperventilation, photostimulation, 24-hour EEG and sleep-deprivation EEG's were carried out as well as CCT or NMR investigation. In 15 patients the loss of consciousness was judged to be due to an epileptic seizure. None of the 21 patients had epileptic potentials in EEG recordings or showed an epileptic seizure during or after TMS, hyperventilation or photostimulation. One patient developed spike-wave activity in the sleep-deprivation EEG, another in the 24-hour EEG. On the basis of our results and previous reports, TMS does not seem to be helpful in the diagnosis of loss of consciousness of unknown origin. However, TMS can be used more liberally than hitherto in the study of motor pathways, in cases with a history of single epileptic seizures.