Identifying potential surgical candidates in patients with evidence of bitemporal epilepsy.
OBJECTIVE
To determine which patients with evidence of medically refractory bitemporal epilepsy are potentially good candidates for surgical therapy.


METHODS
We reviewed 42 adults with intractable seizures who were found to have bitemporal ictal onsets, based on scalp video-EEG long-term monitoring (LTM). All underwent invasive LTM before surgery. Surgical outcomes were classified as seizure free, >75% reduction in seizures, or <75% reduction in seizures, >or=1 year after resection. We related the following factors to outcome: (a). >75% preponderance of interictal scalp EEG discharges to one temporal region; (b). magnetic resonance imaging (MRI) findings; (c). lateralizing deficits on verbal or visual reproduction memory testing; and (d). memory failure with injection contralateral to side of surgery on Wada testing.


RESULTS
Twenty-six (62%) of 42 patients had unilateral ictal onsets based on intracranial studies. Seizure freedom (occurring in 64% of this group), or >75% seizure reduction (found in 12% of subjects) occurred only when at least one of the following three factors was concordant with the side of surgery: preponderance of interictal scalp EEG discharges, unilateral temporal lesion on MRI, or lateralizing verbal or visual reproduction memory deficits on neuropsychological tests (p = 0.004). Seven subjects with bilateral ictal onsets based on intracranial studies had resections based on preponderance of seizures to one side, or other lateralizing noninvasive abnormality. Five of these (all of whom had >or=80% of seizures originating from one side) had >75% reduction in seizures.


CONCLUSIONS
Invasive monitoring to pursue possible surgical therapy for patients with surface EEG evidence of bitemporal epilepsy may be justified only when some lateralizing feature is found in other noninvasive assessments.
Holmes
Mark D
MD
Department of Neurology, University of Washington School of Medicine, Seattle, Washington, USA. mdholmes@u.washington.edu
Miles
Andrew N
AN
Dodrill
Carl B
CB
Ojemann
George A
GA
Wilensky
Alan J
AJ
D000293:Adolescent; D000328:Adult; D000654:Amobarbital; D038481:Anterior Temporal Lobectomy; D004292:Dominance, Cerebral / Q000502:physiology*; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011939:Mental Recall / Q000502:physiology; D008875:Middle Aged; D018670:Monitoring, Ambulatory; D009483:Neuropsychological Tests; D018579:Patient Selection; D013702:Temporal Lobe / Q000503:physiopathology / Q000601:surgery; D016896:Treatment Outcome; D014741:Video Recording
D000654:Amobarbital