Absolute spike frequency as a predictor of surgical outcome in temporal lobe epilepsy.
OBJECTIVE
Frequent interictal epileptiform abnormalities may correlate with poor prognosis after temporal lobe resection for refractory epilepsy. To date, studies have focused on limited resections such as selective amygdalohippocampectomy and apical temporal lobectomy without hippocampectomy. However, it is unclear whether the frequency of spikes predicts outcome after standard anterior temporal lobectomy.


METHODS
Preoperative scalp video-EEG monitoring data from patients who subsequently underwent anterior temporal lobectomy over a three year period and were followed for at least one year were reviewed for the frequency of interictal epileptiform abnormalities. Surgical outcome for those patients with frequent spikes (>60/h) was compared with those with less frequent spikes. Additionally, spike frequency was evaluated as a continuous variable and correlated with outcome to determine if increased spike frequency correlated with worse outcome, as assessed by modified Engel Class outcome.


RESULTS
Forty-seven patients (18 men, 29 women; mean age 40 years at surgery) were included. Forty-six patients had standard anterior temporal lobectomy (24 right, 22 left) and one had a modified left temporal lobectomy. There was no significant difference in seizure outcome between those with frequent (57% Class I) vs. those with less frequent (58% Class I) spikes. Increased spike frequency did not correlate with worse outcome. Greater than 20 complex partial seizures/month and generalized tonic-clonic seizures within one year of surgery correlated with worse outcome.


CONCLUSIONS
This study suggests that absolute spike frequency does not predict seizure outcome after anterior temporal lobectomy unlike in selective procedures, and should not be used as a prognostic factor in this population.
Cooper Medical School of Rowan University, Department of Neurology, Camden, NJ 08103, United States. Electronic address: ngo-ly@cooperhealth.edu.
Ly
L
Ngo
Jefferson Comprehensive Epilepsy Center, Thomas Jefferson University Hospital, Philadelphia, PA, United States.
Michael R
MR
Sperling
Jefferson Comprehensive Epilepsy Center, Thomas Jefferson University Hospital, Philadelphia, PA, United States.
Christopher
C
Skidmore
Jefferson Comprehensive Epilepsy Center, Thomas Jefferson University Hospital, Philadelphia, PA, United States.
Scott
S
Mintzer
Jefferson Comprehensive Epilepsy Center, Thomas Jefferson University Hospital, Philadelphia, PA, United States.
Maromi
M
Nei
D000293:Adolescent; D000328:Adult; D038481:Anterior Temporal Lobectomy / Q000379:methods; D001921:Brain / Q000503:physiopathology* / Q000601:surgery*; D000069279:Drug Resistant Epilepsy / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D004569:Electroencephalography / Q000379:methods; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012815:Signal Processing, Computer-Assisted; D016896:Treatment Outcome; D055815:Young Adult
Epilepsy surgical outcome; Spike frequency; Temporal lobe epilepsy