by histopathological examination of the resected tissue. All additional non-invasive diagnostic findings were concordant with the MRI diagnosis. No additional pathology was indicated. At the time of clinical evaluation of these patients, intracranial electrode implantation was deemed necessary to confirm diagnosis prior to resective surgery (cf. Diehl and Luders, 2000). The EEG study was approved by the medical ethics committee of the University of Bonn. Each patient gave written informed consent.
