Abstracts

Frequent epileptiform interictal discharges on scalp EEG may predict the need for corticoamygdalohippocampectomy.
We retrospectively analyzed 15 consecutive patients seen at West Virginia University Epilepsy Program. All these patients had medically intractable partial seizure disorder, with a typical clinical semiology of mesial temporal lobe epilepsy.
Our typical surgical approach is a selective amygdalohippocampectomy, unless intraoperative electrocorticography points to a neocortical involvement as well.
During the inpatient stay for the video EEG monitoring, a 4-hour sleep deprived spike count was done in all patients. A high (over 350 spikes in the 4 hour period) was found in 4 patients, as compared to an average of 138 in the remaining patients, lateralized to the ipsilateral temporal lobe. The epileptiform abnormalities consisted of high amplitude discharges ([gt] 150 uV) in the ear referential montage, sometimes occurring in bursts with a frequency of 0.2-1 Hz.
In the 4 patients described above, the MRI of the brain showed no evidence of lateral temporal lobe abnormalities, but clear evidence of mesial temporal lobe sclerosis. Intraoperative electrocorticography showed impressive epileptiform discharges from epicortical electrodes placed over the temporal gyrus, occurring independently from the ones emanating from the mesial structures. During the surgery these 4 patients underwent cortical resection in addition to the standard amygdalohippocampectomy.
Macroscopically, prominent scarring was seen over the lateral temporal surface and a history of meningitis was obtained during the initial clinical interview.
Frequent epileptiform interictal discharges consisting of single spike and sharp waves seen during the 4 hour sleep deprived period of video EEG monitoring, may predict the need for corticoamygdalohippocampectomy, rather than selective amygdalohippocampectomy. A history of childhood meningitis was elicited in all these patients.