title: The enigma of the latent period in the development of symptomatic acquired epilepsy - Traditional view versus new concepts.
abstract: A widely accepted hypothesis holds that there is a seizure-free, pre-epileptic state, termed the "latent period", between a brain insult, such as traumatic brain injury or stroke, and the onset of symptomatic epilepsy, during which a cascade of structural, molecular, and functional alterations gradually mediates the process of epileptogenesis. This review, based on recent data from both animal models and patients with different types of brain injury, proposes that epileptogenesis and often subclinical epilepsy can start immediately after brain injury without any appreciable latent period. Even though the latent period has traditionally been the cornerstone concept representing epileptogenesis, we suggest that the evidence for the existence of a latent period is spotty both for animal models and human epilepsy. Knowing whether a latent period exists or not is important for our understanding of epileptogenesis and for the discovery and the trial design of antiepileptogenic agents. The development of antiepileptogenic treatments to prevent epilepsy in patients at risk from a brain insult is a major unmet clinical need.
authors.affiliation: Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany. Electronic address: wolfgang.loescher@tiho-hannover.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Löscher
authors.affiliation: Department of Neurology, Yale University, New Haven, CT 06831, USA.
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Hirsch
authors.affiliation: Epilepsy Research Group, 14163 Berlin, Germany. Electronic address: dbschmidt@t-online.de.
authors.forename: Dieter
authors.initials: D
authors.lastname: Schmidt
mesh_terms: D000818:Animals; D001930:Brain Injuries / Q000150:complications / Q000503:physiopathology; D004195:Disease Models, Animal; D004827:Epilepsy / Q000209:etiology* / Q000503:physiopathology / Q000523:psychology; D006801:Humans; D020521:Stroke / Q000150:complications / Q000503:physiopathology
keywords: Animal models; Early and late seizures; Epileptogenesis; Kindling; Temporal lobe epilepsy; Traumatic brain injury