[Electric-sensoric examination and EEG to localize the focus of symptomatic epilepsy (author's transl)].

Somatosensory cortical evoked potentials (SRAP) have been studied in normal subjects and in epileptic patients. The value of this method with regard to intracerebral localization was compared with the results obtained by EEG, scintigraphy, arteriography and surgical exploration. Contralateral evoked potentials were recorded after electrical stimulation of the dorsum of the foot (spinal segment L5) and the ulnar side of the hand (spinal segment C7 or C8). Details of the methods are published elsewhere (Baust et al., 1972). In cases of symptomatic epilepsy the evoked potentials were abnormal, pathological or absent over the specific cortical area independent of whether there was an EEG focus or not. In cases with a normal EEG the changes in the evoked potentials were seen over that hemisphere which was localized by scintigramm, arteriography or surgery as being the side of the lesions (Fig. 1). The patients investigated here suffered from jacksonian epilepsy or grand mal with focal origin; pathologically the angiomas are to be mentioned in particular where the SRAP alterations, and not the EEG, demonstrate the damaged hemisphere (Fig.2). It can be concluded that the study of somatosensory evoked potentials can give more detailed information than the conventional EEG in cases of symptomatic epilepsy with a normal EEG.