EEG and Seizure Outcome After Epilepsy Surgery

Suzanne Patrick, Anne Berg, Susan S. Spencer*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


Summary: The significance of the EEG after epilepsy surgery is not fully understood. We investigated the as‐ sociation between postoperative EEG abnormalities and persistent seizures after epilepsy surgery as they relate to pathologic lesions. Among 254 patients who underwent epilepsy surgery between 1987 and 1991, we identified 78 patients who had mesiotemporal sclerosis (MTS) and 47 patients who had low‐grade brain tumors, all of whom had 6‐to 18‐month postoperative follow‐up including EEG. Patients who had other pathology, multiple operations, callosotomy, or hemispherectomy, or who were aged <18 years or who had insufficient EEG data, were excluded. Patients were classified as having persistent seizures or being seizure‐free since operation. EEG abnormalities were abstracted from EEG reports 6–18 months postoperatively. Seizures persisted in 24% of the MTS group and in 27% of the tumor group. Of those with normal EEGs, none of the MTS patients and only 1 of the tumor patients had persistent seizures (p = 0.03 for MTS and p = 0.42 for tumor). Epileptiform discharges and focal slowing were associated with seizure persistence in both groups, but to a significant extent only in the MTS group. In the MTS group, patients who had both epileptiform discharges and focal slowing were more likely to have persistent seizures than were those with either abnormality alone.

Original languageEnglish (US)
Pages (from-to)236-240
Number of pages5
Issue number3
StatePublished - Mar 1995


  • Electroencephalography
  • Epilepsy
  • Neurosurgery
  • Seizure outcome

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology


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