The classification has been revised. Seizures are divided into those of focal, generalized, unknown onset, with subcategories of motor, nonmotor, with retained or impaired awareness for focal seizures.
Levels of classification to aid in the diagnosis include seizure type, epilepsy type (focal, generalized, combined generalized and focal, unknown), and epilepsy syndrome.
This 2017 Cochrane review supports:
The use of carbamazepine and lamotrigine as first-line treatments for adults and children with focal-onset seizures.
The use of levetiracetam as a suitable alternative if carbamazepine and lamotrigine are unsuitable or not tolerated.
Electrical and clinical manifestations of seizures that arise from one portion of the brain. May evolve to bilateral tonic-clonic seizures.
Underlying structural brain abnormalities are known to cause a localized epileptiform focus, but idiopathic cases may occur.
History taking is the most important aspect of diagnosis. Supportive tests, although helpful, need not be abnormal for a diagnosis of focal seizures.
Monotherapy with antiepileptic medication is the preferred treatment. When polytherapy is required, this should be approached rationally, by considering the combination of different mechanisms of action and different adverse-event profiles.
Patients with 2 failed monotherapy trials followed by a failed trial of polytherapy are considered to have refractory focal seizures, and should be evaluated for the possibility of resective epilepsy surgery.
Focal (or partial) seizures refer to the electrical and clinical manifestations of seizures that arise from one portion of the brain. The EEG typically indicates a localized discharge over the area of onset. Focal seizures most commonly arise from the temporal lobe. Simple partial seizures are those in which consciousness is preserved. New terminology suggests that these should now be called "focal aware seizures". Complex partial seizures include memory loss for the clinical event and impaired responsiveness at the time of the event. New terminology suggests that these should now be called "focal impaired awareness seizures". Focal seizures may evolve into secondary generalized seizures. The clinical manifestations of a particular seizure depend on the portion of the brain that is activated. 
In 2009, a task force supported by the International League Against Epilepsy (ILAE) issued a report revising the system of terminology and classification used for the description of individual seizures and epilepsy syndromes.  The clinical definition of epilepsy was revised in 2014 to include any of the following conditions: 1) at least two unprovoked seizures occurring >24 hours apart; 2) one unprovoked seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years; 3) diagnosis of an epilepsy syndrome.  
University of California, San Francisco
VRR is an author of a number of references cited in this monograph. He received honoraria and travel expenses for speaking at educational events hosted by NeuroPace, Inc., manufacturer of the Responsive Neurostimulation (RNS) System, and is a paid consultant for them.
University of California, San Francisco
JDH has received research grant support from UCB Inc, he has done consulting work for Lumetra Healthcare Solutions, California Medical Board, Freshblood Market Consultants, and given expert witness testimony for Actavis and Zydus Inc. He is also on the advisory board for Acorda Therapeutics.
Dr Vikram R. Rao and Dr John D. Hixson would like to gratefully acknowledge Dr Jeffrey Cohen, a previous contributor to this monograph. JC declares that he has no competing interests.
Brigham and Women's Hospital
Associate Professor of Neurology
Harvard Medical School
At the time of review, EB declared that between 2004 and 2009, he received speaking honoraria from UCB Pharma, Novartis, Abbott Laboratories, GlaxoSmithKline, and Pfizer. He received consulting fees from UCB Pharma, Genzyme, and Spherics, and research funding from UCB Pharma. Unfortunately, we have since been made aware that EB is deceased.
Pediatrics and Neurology
Baylor College of Medicine
Comprehensive Epilepsy Program
Texas Children's Hospital
AAW declares that he has no competing interests.
Division of Pediatric Neurology
Columbia University College of Physicians and Surgeons
Muscular and Neurodegenerative Diseases Unit
"G Gaslini" Institute
Federico II University
PS declares that he has no competing interests.
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