title: Postoperative EEG and seizure outcome in temporal lobe epilepsy surgery.
abstract: OBJECTIVE
  To assess the prognostic value of scalp electroencephalogram (EEG) after epilepsy surgery, we investigated whether postoperative EEG abnormalities (interictal epileptiform discharges, IED; interictal slow activity, ISA) were associated with seizure outcome and other patient characteristics after resective surgery in patients with temporal lobe epilepsy (TLE).
  
  
  METHODS
  Sixty-two patients with medically refractory TLE who underwent surgery were studied. Patients were categorized according to etiology (mesiotemporal sclerosis vs. tumors/cortical dysplasias); extent of surgical resection (extensive vs. limited); and amount of preoperative IED on wake EEG (oligospikers, <1 IED/h, vs. spikers). Patients were also classified as seizure-free (SF) or having persistent seizures/auras (not-SF) during follow up visits 1 month and 1 year after surgery. Preoperative 60-min interictal EEGs were evaluated for IED and ISA, and compared to postoperative wake EEGs.
  
  
  RESULTS
  Seizures/auras persisted in 16/62 (25.8%) patients at 1 month and in 8/62 (12.9%) at 1 year follow up. ISA was not significantly related to outcome. Of 42 patients with EEG negative for IED at 1 month, 4 were not-SF; at 1 year, one of 44 such patients was not-SF. IED was significantly associated with seizure/aura persistence in patients categorized as mesiotemporal sclerosis and with extensive surgery. Oligospikers and spikers on preoperative EEG showed no differences in the postoperative seizure outcome, excellent in both cases; moreover, the presence of postoperative IEDs indicated auras/seizures persistence apart from the preoperative EEG spike frequency.
  
  
  CONCLUSIONS
  Our study showed that the presence of IED of postoperatve EEG strongly indicates seizure/aura persistence. Therefore, serial EEGs should be included in postoperative follow up schedules as a crucial tool in evaluating seizure outcome.
authors.affiliation: Epilepsy Surgery Unit, Department of Neurosciences, IRCCS NEUROMED, via Atinense, 18, 86077 Pozzilli (IS), Italy. gdigennaro@neuromed.it
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Di Gennaro
authors.forename: Pier Paolo
authors.initials: PP
authors.lastname: Quarato
authors.forename: Fabio
authors.initials: F
authors.lastname: Sebastiano
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Esposito
authors.forename: Paolo
authors.initials: P
authors.lastname: Onorati
authors.forename: Addolorata
authors.initials: A
authors.lastname: Mascia
authors.forename: Pantaleo
authors.initials: P
authors.lastname: Romanelli
authors.forename: Liliana G
authors.initials: LG
authors.lastname: Grammaldo
authors.forename: Carolina
authors.initials: C
authors.lastname: Falco
authors.forename: Ciriaco
authors.initials: C
authors.lastname: Scoppetta
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Eusebi
authors.forename: Mario
authors.initials: M
authors.lastname: Manfredi
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Cantore
mesh_terms: D000293:Adolescent; D000328:Adult; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology* / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D011184:Postoperative Period; D011300:Preoperative Care; D016896:Treatment Outcome