The history of invasive EEG evaluation in epilepsy patients

Modern invasive EEG recording techniques are the result of an interdisciplinary research process between neurologists and neurosurgeons that began in the 19th century. In the beginning, stimulation studies were the basis of our understanding of cortical functions. After the introduction of EEG in humans by Hans Berger and its implementation in diagnostic procedures in epilepsy patients, a new era began when Forster and Altenburger performed the first invasive EEG recording five years later. The fruitful work of Wilder Penfield and Herbert Jasper was the basis of a new understanding of epilepsy and influenced the investigations of the next generation of researchers. The development of stereotactic devices advanced by Jean Talairach and Jean Bancaud was fundamental to the understanding of deep brain functions and pathophysiological processes in epilepsy patients. In subsequent decades, new recording techniques were established and long-term video-EEG-recordings became the gold standard in presurgical evaluation. The development of imaging techniques allowed a combination of structural and electrophysiological data and restricted the indications for invasive evaluations, but also led to new concepts in the diagnostic process, including the epileptogenic network and the pathophysiological understanding of epileptogenic tissue. The following article provides an overview of the history of invasive EEG evaluation in epilepsy from the 19th century until today.