The clinical concept of epilepsy.

This article reviews the history of clinical concepts of epilepsy and its classification, especially in the last 100 years. Throughout its recorded history of 3 to 4 millennia, epilepsy has always been defined by its most dramatic symptoms, for example, falling, motor activity or loss of consciousness, but separation from other causes of the same paroxysmal symptoms has always proved challenging. For over a century there has been some semantic confusion whether to call the various paroxysms fits, convulsions, seizures, or epilepsies. Since the middle of the 19th century a great unresolved debate has continued about whether recurrent seizures or epilepsy should be viewed as a separable symptom of underlying brain disease or as one or more idiopathic diseases or syndromes, with an inherent age-related natural history; or indeed viewed as both a symptom and a disease. A major advance in the 20th century is that vascular theories of epilepsy, which reached their peak with Turner in 1907, have been replaced by electromagnetic discharges, based especially on the work of Todd, Jackson, Berger, Lennox, and the Gibbs, culminating eventually in new ILAE classifications of seizures (1981) and epilepsy syndromes (1989). However 21st century uncertainties about symptomatic versus idiopathic or cross-sectional (seizures) versus longitudinal (epilepsy) approaches to the problem very much reflect similar divergences of view a century ago. More attention is now being directed at interseizure events and processes which may lead either to remission or intractability with associated cognitive and psychosocial consequences. The search for the elusive essence, diathesis or predisposition to epilepsy, including seizure threshold, continues.