A critical review of the different conceptual hypotheses framing human focal epilepsy.

In the attempt to understand the processes affecting human focal epilepsy, various models that have been proposed as a back drop to which current observations of the clinical manifestations and therapies in this disorder can be tested. There are three main models that are reviewed. The notion of epileptogenicity as described by Penfield and Jasper's epileptogenic zone model postulates that specific regions of cerebral cortex have varying degrees of importance in the generation of focal epilepsy. A variation of this hypothesis comprises the second model put forth by Talairach and Bancaud. In this view the notion of the epileptogenic zone is expanded to incorporate a larger regions of cerebral cortex involved in the seizure propagation. A third concept and more separate hypothesis suggests that all components of the neural network involved in focal epilepsy are equally importance in the initiation and maintenance of the seizure. The various concepts underlying these models are reviewed in this paper and data from clinical and neurophysiologic observations are discussed in the context of these models. We suggest in this paper that the data best supports the epileptogenic zone hypothesis put forth by Penfield and Jasper.