The borderland between epilepsy and movement disorders

Abstract

Introduction The term �borderland of epilepsy� was coined by William Richard Gowers in 1907 when he described the borderland as disorders �near it (epilepsy), but not of it� (Crompton and Berkovic 2009). Brief paroxysmal stereotyped events are the cardinal feature in both epilepsy and paroxysmal movement disorders (PMD). A seizure is an abnormal synchronous burst of neuronal activity, with epilepsy defined as a propensity to having seizures. Epilepsy is differentiated from movement disorders by the presence of characteristic ictal and interictal discharges on electroencephalography (EEG) and events may evolve into or be associated with generalized tonic-clonic or other seizures. Cortical involvement is a key factor in epileptic seizures, with the disruption between cortical and subcortical pathways influencing the semiology of the events. Altered functioning of subcortical structures is primarily implicated in generating PMD, although hypersynchronous discharges have not been disproved as the basis for PMD (Berkovic 2000). Unlike generalized or complex partial seizures, movement disorders, in general, do not cause impaired consciousness. However, some seizures may cause very subtle alterations in mentation and in a number of sleep-related movement disorders patients have no recollection of the events. In addition, distinguishing between epilepsy and PMD in patients with developmental delay, impaired cognition, or altered mental status may present even greater difficulty. � Cambridge University Press 2014.