The concept of symptomatic epilepsy and the complexities of assigning cause in epilepsy.

The concept of symptomatic epilepsy and the difficulties in assigning cause in epilepsy are described. A historical review is given, emphasizing aspects of the history which are relevant today. The historical review is divided into three approximately semicentenial periods (1860-1910, 1910-1960, 1960-present). A definition of symptomatic epilepsy and this is followed by listing of causes of symptomatic epilepsy. The fact that not all the causes of idiopathic epilepsy are genetic is discussed. A category of provoked epilepsy is proposed. The complexities in assigning cause include the following: the multifactorial nature of epilepsy, the distinction between remote and proximate causes, the role of nongenetic factors in idiopathic epilepsy, the role of investigation in determining the range of causes, the fact that not all symptomatic epilepsy is acquired, the nosological position of provoked epilepsy and the view of epilepsy as a process, and the differentiation of new-onset and established epilepsy. The newly proposed ILAE classification of epilepsy and its changes in terminologies and the difficulties in the concept of acute symptomatic epilepsy are discussed, including the inconsistencies and gray areas and the distinction between idiopathic, symptomatic, and provoked epilepsies. Points to be considered in future work are listed.