Prognostic significance of serial postoperative EEG in extratemporal lobe epilepsy surgery.
OBJECTIVE
To assess the prognostic value of postoperative EEG in patients surgically treated for drug-resistant extra-temporal lobe (ET) epilepsy.


METHODS
We studied 63 consecutive patients with ET epilepsy who underwent epilepsy surgery and were followed up for at least 2 years (mean duration of follow-up 6.2 ± 2.3 years, range 2-12). Follow-up evaluations were performed 2, 12, and 24 months after surgery, and included standard EEG (at 2 months) and long-term video-EEG monitoring during both wakefulness and sleep (at 12 and 24 months). Seizure outcome was determined at each follow-up evaluation, and then at yearly intervals. Patients who were in Engel Class I at the last contact were classified as having a good outcome.


RESULTS
Seizure outcome was good in 39 patients (62%). The presence of interictal epileptiform discharges (IED) in postoperative EEG at each time point was found to be associated with poor outcome. The strength of this association was greater for awake plus sleep recording as compared with awake recording alone. In a multiple regression model including all pre- and post-operative factors identified as predictors of outcome in univariate analysis, the presence of early (2 months after surgery) EEG epileptiform abnormalities was found to be independently associated with poor seizure outcome.


CONCLUSIONS
Postoperative IED may predict long-term outcome in patients undergoing resective surgery for ET epilepsy.


CONCLUSIONS
The increase in risk of unfavourable outcome associated with EEG epileptiform abnormalities detected as early as two months after surgery may have substantial practical importance. Serial postoperative EEGs including sleep recording may add further predictive power and help making decision about antiepileptic drug discontinuation.
Epilepsy Surgery Unit, Department of Neurological Sciences, IRCCS NEUROMED Pozzilli (IS), Italy. gdigennaro@neuromed.it
Giancarlo
G
Di Gennaro
Marco
M
De Risi
Pier Paolo
PP
Quarato
Antonio
A
Sparano
Addolorata
A
Mascia
Liliana G
LG
Grammaldo
Giulio N
GN
Meldolesi
Vincenzo
V
Esposito
Angelo
A
Picardi
D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004827:Epilepsy / Q000517:prevention & control; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D011184:Postoperative Period; D011379:Prognosis; D012890:Sleep / Q000502:physiology; D016896:Treatment Outcome; D055815:Young Adult
D000927:Anticonvulsants