Long-term electroencephalography follow-up of patients with selective amygdaloid-hippocampectomy

The EEGs of 149 patients with drug-resistant psychomotor epilepsy were analysed before and after amygdalohippocampectomy. The extent of the pre- and postoperative EEG abnormalities was compared. In particular we were interested whether there is a difference in patients with a structural lesion compared to those with no structural lesion, and if so, in which EEG-parameters the difference lies (background activity, homo- and contralateral focal slowing, homo- and contralateral epileptogenic focus, generalized epileptiform abnormalities). Furthermore we studied whether the postoperative clinical outcome correlates with the pre- and postoperative EEG-parameters. In patients with a structural lesion the homolateral focal slowing is preoperatively more pronounced than in patients with no structural lesion. In patients with no structural lesion all other preoperative EEG-parameters are more pathological. The preoperative EEG-parameters are only of limited predictive value for the clinical outcome. The amount of the improvement of postoperative EEG-parameters correlates well with the clinical outcome.