Applicability and contribution of the new ILAE 2017 classification of epileptic seizures and epilepsies.

The aim of the study was to evaluate the clinical applicability of the 2017 ILAE classification of seizures and epilepsies through the analysis of a sample of 100 outpatients with a diagnosis of epilepsy. All clinical charts were reviewed applying both the 1981/1989 and 2017 classifications of seizures and epilepsies, respectively. For most focal seizures, descriptors were required to include all the relevant clinical information. The reclassification of complex partial seizures into focal seizures with impaired awareness with a motor / non-motor onset allowed the inclusion of features of topographic value, although the chronological sequence of awareness impairment was lacking. The use of the term "focal to bilateral tonic-clonic" reduced the number of seizures classified as generalized tonic-clonic seizures (GTCS) by 19%. A subset of GTCS (35%) and absence seizures (12.5%) were reclassified as seizures of unknown onset. Most focal symptomatic epilepsies (92%) were reclassified as focal structural epilepsies, while 27% of idiopathic generalized and 7% of focal cryptogenic epilepsies merged into the category of "epilepsies of unknown type". Major strengths of the new classification are simplicity and the role of the category "unknown onset" to avoid forced categorization. A section assigned to uncertainty reinforces the need for further ancillary studies and periodic diagnostic re-evaluation.