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ObjectiveThe International League Against Epilepsy (ILAE) has revised the classification of epilepsies and seizures on several occasions since the original classification published in 1964. It is unclear if these changes have impacted the characterization of epilepsy, including the clinical validity of seizure semiology or epilepsy outcomes in resource poor areas. We aim to address this important knowledge gap.MethodsWe reviewed clinical, seizure semiology and aetiological data of 483 persons with epilepsy identified from a population-based survey in rural Kenya. The seizure semiology and aetiological data were classified using the 1981 (for seizures) and 1989 (for epilepsy) ILAE criteria and then re-classified according to ILAE-2017 criteria. Logistic regression models adjusted for potential confounders were used to measure associations between seizure semiology and different clinical and electroencephalographic features of epilepsy.ResultsFocal (formerly localization-related) and generalized epilepsies were lower in ILAE-2017 (56% and 29%) than ILAE-1989 (61% and 34%), p<0.001 and p<0.001). Combined focal and generalized epilepsy type in ILAE-2017 accounted for 11% of epilepsies. Individual seizure types were statistically similar in both ILAE-1981 and 2017. New classification categories in ILAE-2017 such as unknown seizures and epilepsies were identified, and the proportions were similar to the unclassified category in ILAE-1989, 6% and 5% respectively. The most common causes of epilepsy were symptomatic (76%) in ILAE-1989, with infectious (45%) and structural (36%) causes were highest in ILAE-2017 criteria.SignificanceOur study confirms that the two ILAE classification schemes are broadly consistent, but the introduction of combined onset seizures category in ILAE-2017 significantly reduces the proportion of mutually exclusive focal and generalized seizures. The comprehensive classification of aetiology categories in ILAE-2017 will facilitate appropriate treatment and improve prognosis.

Original publication





Epilepsia open

Publication Date



Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Kilifi, Kenya.