Basic Terminology in Epilepsy

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3865130/

The Commission on Epidemiology and Prognosis (CEP) of the International League Against Epilepsy (ILAE) proposed conceptual and operational definitions of epilepsy and other paroxysmal events. These terms were established by consensus (1), initially in 1993, to provide a common language in the epidemiological, clinical and therapeutical studies and for the daily practice. Some term definitions were questioned during last years, and conceptual modifications were proposed (2). In 2011 CEP – ILAE published a document promoting consistency in methods and definitions (3). We present the useful terms in daily clinical practice:

Epileptic seizure – "a transient occurence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain" – 2005 (2). "The clinical manifestation consist of sudden and transitory abnormal phenomena which may include alterations of consciousness, motor, sensory, autonomic, or psychic events, perceived by the patient or an observer" – 1993 (1).

Status epilepticus – "a single epileptic seizure of more than 30-min duration or a series of epileptic seizures without resumption of baseline central nervous system functions interictally lasting more than 30-min" – 1993 (1).

Epilepsy – operational definition – is still recommended for epidemiological studies. According to this definition epilepsy is "a condition characterized by recurrent (two or more) epileptic seizures, unprovoked by any immediate identified cause. Multiple seizures occuring in a 24-h period are considered a single event. An episode of status epilepticus is considered a single event" – 1993 (1). The 2005 concept (2), defined epilepsy as "a disorder characterized by an enduring predisposition to generate epileptic seizures and by a neurobiologic, cognitive, psychological and social consequences of this condition. The definition requires the occurence of at least one epileptic seizure". This concept is more difficult to manage, consequently it is considered that epilepsy should be recognized by any pshysician but the epilepsy diagnosis should be established by physicians with epileptology expertise.

Nonepileptic events – "clinical manifestations presumed to be unrelated to an abnormal and excessive discharge of a set of neurons of the brain, including: disturbances in brain function (vertigo or dizziness, syncope, sleep and movement disorders, transient global amnesia, migraine, enuresis) and pseudoseizures (non­epileptic sudden behavioral episodes presumed to be of psychogenic origin; these may coexist with true epileptic seizures)" – 1993 (1)