title: Prognostic value of intracranial seizure onset patterns for surgical outcome of the treatment of epilepsy.
abstract: OBJECTIVE
  To investigate if intracranial EEG patterns at seizure onset can predict surgical outcome.
  
  
  METHODS
  Ictal onset patterns from intracranial EEG were analysed in 373 electro-clinical seizures and subclinical seizures from 69 patients. Seizure onset patterns were classified as: (a) Diffuse electrodecremental (DEE); (b) Focal fast activity (FA); (c) Simultaneous onset of fast activity and diffuse electrodecremental event (FA-DEE); (d) Spikes; (e) Spike-wave activity; (f) Sharp waves; (g) Alpha activity; (h) Delta activity. Presence of preceding epileptiform discharge (PED) was also studied. Engel and ILAE surgical outcome scales were used.
  
  
  RESULTS
  The mean follow-up period was 42.1 months (SD=30.1). Fast activity was the most common seizure onset pattern seen (33%), followed by (FA-DEE) (20%), DEE (19%), spike-wave activity (12%), sharp-waves (6%), alpha activity (6%), delta activity (3%) and spikes (1%). Preceding epileptiform discharges were present in 75% of patients. FA was associated with favourable outcome (p=0.0083) whereas DEE was associated with poor outcome (p=0.0025). A widespread PED was not associated with poor outcome (p=0.9559). There was no clear association between seizure onset pattern and specific pathology, except possibly between sharp/spike waves and mesial temporal sclerosis.
  
  
  CONCLUSIONS
  FA activity is associated with favourable outcome. DEE at onset was associated with poor surgical outcome. Widespread/bilateral PEDs were not associated with poor or good outcome.
  
  
  CONCLUSIONS
  FA appears to be the best marker for the epileptogenic zone. Surgery should be contemplated with caution if DEE is the first ictal change. However, a widespread/bilateral PED at onset is common and should not discourage surgery.
authors: Department of Clinical Neuroscience, King's College London, Institute of Psychiatry, UK; Department of Clinical Neurophysiology, King's College Hospital NHS Trust, London, UK; Universidad San Francisco de Quito, School of Medicine, Quito, Ecuador.
authors: Diego
authors: D
authors: Jiménez-Jiménez
authors: Department of Clinical Neuroscience, King's College London, Institute of Psychiatry, UK.
authors: Ramesh
authors: R
authors: Nekkare
authors: Department of Clinical Neuroscience, King's College London, Institute of Psychiatry, UK.
authors: Lorena
authors: L
authors: Flores
authors: Department of Clinical Neuroscience, King's College London, Institute of Psychiatry, UK.
authors: Katerina
authors: K
authors: Chatzidimou
authors: Department of Neuropathology, King's College Hospital NHS Trust, London, UK.
authors: Istvan
authors: I
authors: Bodi
authors: Department of Neuropathology, King's College Hospital NHS Trust, London, UK; Serviço de Anatomia Patológica, Hospital Pedro Hispano, Matosinhos, Portugal.
authors: Mrinalini
authors: M
authors: Honavar
authors: Department of Clinical Neurophysiology, King's College Hospital NHS Trust, London, UK.
authors: Nandini
authors: N
authors: Mullatti
authors: Department of Clinical Neurophysiology, King's College Hospital NHS Trust, London, UK.
authors: Robert D C
authors: RD
authors: Elwes
authors: Department of Neurosurgery, King's College Hospital NHS Trust, London, UK.
authors: Richard P
authors: RP
authors: Selway
authors: Department of Clinical Neuroscience, King's College London, Institute of Psychiatry, UK; Department of Clinical Neurophysiology, King's College Hospital NHS Trust, London, UK.
authors: Antonio
authors: A
authors: Valentín
authors: Department of Clinical Neuroscience, King's College London, Institute of Psychiatry, UK; Department of Clinical Neurophysiology, King's College Hospital NHS Trust, London, UK; Departamento de Fisiología, Facultad de Medicina, Universidad Complutense, Madrid, Spain. Electronic address: gonzalo.alarcon@kcl.ac.uk.
authors: Gonzalo
authors: G
authors: Alarcón
mesh_terms: D000328:Adult; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000295:instrumentation / Q000379:methods*; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011379:Prognosis; D012640:Seizures / Q000175:diagnosis* / Q000503:physiopathology* / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult
keywords: Epilepsy surgery; Intracranial EEG; Invasive recordings; Seizure onset; Surgical outcome