**1. Introduction**

Epilepsy is a chronic disease of the brain estimated to affect 50 million people worldwide according to World Health Organization (WHO) [1]. It is characterized by repetitive, unprovoked epileptic seizures which vary widely in their clinical presentations. Although a meticulous patient history complemented by sound clinical/paraclinical investigations often unveil the underlying cause of epilepsy, the exact etiology remains unknown in about half of cases [2]. Proper diagnosis and treatment of epilepsy are paramount to achieve seizure control and ensure an optimal quality of life for affected individuals.

### **1.1 Definition of epilepsy**

In 2005, the International League Against Epilepsy (ILAE) defined epilepsy as "a disorder of the brain characterized by an enduring predisposition to generate epileptic seizures, and by the neurobiologic, cognitive, psychological, and social consequences of this condition" [3]. An epileptic seizure, on the other hand, refers to "a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain" [3]. While these definitions

remain very conceptual, they are difficult to apply in a real-life clinical setting. Therefore, a Task Force was commissioned to formulate an operational definition of epilepsy; the definition of epilepsy was thus broadened to accommodate three practical circumstances (**Box 1**) [4].

#### **Epilepsy is a disease of the brain defined by any of the following conditions:**


Epilepsy is considered to be resolved for individuals who had an age-dependent epilepsy syndrome but are now past the applicable age or those who have remained seizure-free for the last 10 years, with no seizure medicines for the last 5 years.

#### **Box 1.**

*Operational (practical) clinical definition of epilepsy [4]***.**

Emphasis must be laid on some points in this operational definition. Firstly, the seizures must be unprovoked, and not as a result of an acute, punctual event such as head trauma, substance abuse/withdrawal, metabolic imbalance, infection of the central nervous system or fever. As concerns the minimal risk of recurrence fixed at 60%, it is merely approximative of the likelihood of future seizure (mostly based on paraclinical findings on the electroencephalogram (EEG) or brain imaging [5]) and should not be interpreted as an absolute cut-off [4]. Another point to note is the minimal time difference of 24 hours between the seizures, but without a maximum time interval; in practice, the ILAE maintains the lifetime occurrence of two unprovoked seizures as a diagnostic criterion for epilepsy. Finally, epilepsy syndromes have been elaborately documented by the ILAE; each syndrome is characterized by specific electroclinical and/or genetic features [6].

#### **1.2 Diagnosis of epilepsy**

The diagnosis of epilepsy is essentially clinical. Based on the criteria listed in **Box 1**, the epilepsy diagnosis can be made if an individual fulfills the ILAE criteria. In a hospital setting, the following paraclinical workups can be performed to further investigate the epilepsy diagnosis: EEG, brain imaging (by scan or magnetic resonance), and blood tests (to investigate metabolic or genetic epilepsies).

In field research settings, the ILAE recommends epilepsy assessment using a door-to-door approach [7]. Several tools have been developed for epilepsy screening during epilepsy studies [8–11]; for studies conducted in the sub-Saharan setting in particular, the Institute of Neurological Epidemiology and Tropical Neurology of Limoges (France) developed a questionnaire with the support of the Pan-African Association of Neurological Sciences and the ILAE (Commission on Tropical Diseases, 1993–1997) [11]. This questionnaire was validated in Mauritania (sensitivity: 95.1%; specificity: 65.6%) and has since then been widely used for epilepsy surveys in Africa [11]. It has the advantages of being brief, usable by non-physicians, and diagnosing seizure types other than generalized tonic-clonic episodes (for instance, absences and focal seizures). To ensure accurate outcomes, it is important that a neurologist or physician trained in epilepsy confirms all suspected epilepsy cases clinically, following the ILAE diagnostic criteria.
