Utility of stereoelectroencephalography in preoperative assessment of temporal lobe epilepsy.
Of 269 consecutive patients entered into a preoperative assessment programme for possible surgical treatment of epilepsy, 33 had intracranial recording (SEEG) with combined subdural and depth electrodes for the purpose of localising a suspected temporal site of seizure onset. The findings in these patients are analysed with particular reference to: 1) the criteria of selection for SEEG and their validity; 2) information on SEEG compared with that obtained by less invasive means, including foramen ovale telemetry; 3) information on the use of intracerebral electrodes compared with subdural placements; 4) possible predictors of failure of localisation by SEEG and of surgical outcome. It was concluded that SEEG had usefully contributed to the management of 69% of the patients in whom it was used, establishing a previously unidentified site of seizure onset in 33%, correcting an erroneous localisation in 15%, and establishing inoperability in 21% of patients. No predictors of failure of SEEG or of surgery emerged; thus there was no evidence of unnecessary use of this procedure. Five patients were found with incorrect lateralisation of seizure onset on foramen ovale recording (of a total of 192 foramen ovale telemetries). Localisation of the ictal onset zone either by the distribution of inter-ictal discharges or by the initial ictal changes at subdural electrodes was unreliable, confirming the need for ictal, depth recordings.
Binnie
C D
CD
Department of Clinical Neurophysiology, Maudsley Hospital, London, UK.
Elwes
R D
RD
Polkey
C E
CE
Volans
A
A
D000328:Adult; D001921:Brain / Q000503:physiopathology* / Q000601:surgery; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000379:methods*; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D013686:Telemetry / Q000379:methods*; D016896:Treatment Outcome