Characteristics of electroencephalographic changes after hemispheric disconnection surgery in patients with drug-resistant epilepsy
TL;DR
No significant association was found between postoperative EEG characteristics and prognosis in patients with DRE who underwent hemispheric disconnection surgery, and dynamic alterations are observed in bilateral EEG recordings.
Abstract
Hemispheric disconnection surgery is a safe and effective therapeutic modality for drug-resistant epilepsy (DRE) secondary to hemispheric or multilobar lesions, while the dynamic evolutionary characteristics of postoperative electroencephalogram (EEG) and its clinical prognostic value remain unclear with no relevant systematic follow-up reports currently available. This study aims to retrospectively analyze EEG changes following hemispheric disconnection surgery in patients with DRE and to assess their clinical significance. We enrolled patients with DRE who underwent hemispheric disconnection surgery. EEG data were collected preoperatively and at 3 months, 1 year, and 2 years postoperatively. We analyzed EEG characteristics (including background activity and interictal and ictal patterns) at each time point and evaluated their correlation with prognosis. Sixteen patients met the inclusion criteria; 14 (87.5%) had no seizure recurrence within the 2-year follow-up period. EEG analysis at postoperative time points showed that: (1) The EEG background activity on the ipsilateral side was dominated by slow waves and low-voltage activity. The proportion of low-voltage background activity gradually increased within 1 year, and slow waves became the predominant pattern thereafter. While, the contralateral background activity normalized within 1 year. (2) Epileptiform discharges on the ipsilateral side initially increased then decreased, accompanied by a reversible burst-suppression-like pattern. Epileptiform discharges on the contralateral side gradually decreased and disappeared in most patients (8/11, 72.7%). (3) In this study, seizure recurrence occurred in 2 patients, which was associated with incomplete disconnection and complications. Seizures were subsequently controlled after reoperation. (4) No postoperative EEG features were significantly correlated with prognosis (all P > 0.05). Following hemispheric disconnection, dynamic alterations are observed in bilateral EEG recordings. A postoperative burst-suppression-like pattern is commonly observed on the ipsilateral side. In this small-sample study, no significant association was found between postoperative EEG characteristics and prognosis.