[Professor Hans Otto Lüders]

Professor Lüders has made significant contributions to Clinical Neurology and particularly to Epilepsy and Clinical Neurophysiology. Some of his most important contributions include the following: 1.He pioneered the use of chronically implanted, large plates of subdural electrodes in the presurgical evaluation of patient who were candidates for epilepsy surgery. These electrodes were used to record epileptic seizures and by electrical stimulation to establish the location of eloquent cortex. Lately he has also advocated the use in the USA of stereotactically implanted depth electrodes for presurgical evaluation of epilepsy patients who had deep seated epileptic foci which were impossible to assess with subdural electrodes. These techniques were imported from Europe. 2.Mapping studies with subdural electrodes led to the discovery of a number of cortical eloquent areas that had not been described before: a. The basal temporal language area located in the dominant fusiform gyrus. b. The "negative motor areas" located in the caudal region of the inferior frontal gyrus (bilaterally) and immediately in mesial frontal pre-SMA region (also bilaterally). He concluded that these "negative motor areas" most likely correspond to praxis regions. c. The dominant posterior fusiform gyrus which plays a crucial role in processing reading material. Stimulation of that area produces "alexia without agraphia". 3.He developed a new classification of epileptic seizures based exclusively on semiological ictal characteristics. With the development of the semiological seizure classification he also defined several new seizure types: a. Dialeptic seizures, b. Hypnopompic seizures, c. Hypomotor seizures. 4.Working with general epilepsy principles, he established the existence of 6 zones that characterize the epilepsies: the epileptogenic zone, the irritative zone, the seizure onset zone, the epileptogenic lesion, the symptomatogenic zone and functional deficit zone. 5.He described the ictal DC (direct current) shift seen at the beginning of focal seizures and its value for localization of the seizure onset zone.