Surgical outcome in a group of low-IQ patients with focal epilepsy

Because a low IQ score indicates global brain damage, several authors consider it a contraindication for resective epilepsy surgery. This study reports the postoperative results of a small group of subaverage-intelligence patients with epilepsy who underwent focal resections.

We report on 16 patients who underwent focal resections (no callosotomy or hemispherectomy). All had IQ's <85 and were >13 years of age at the time of surgery. Low IQ was psychometrically assessed (mean IQ = 70) and confirmed by the patients' educational/occupational status. Clinical characteristics, findings from the preoperative workup, and the surgical treatment are described in detail. Postoperative outcome was evaluated with respect to seizure relief and cognitive/ socioeconomic development.

Three months after surgery, 14 (87%) of 16 patients were completely seizure free, and nine (64%) of 14 were seizure free at the 1-year follow-up. Patients' cognitive abilities and socioeconomic status were mostly unchanged and in some cases improved. Seizure outcome was not related to IQ level, and there was no evidence of multiple epileptic foci in the patients with continued seizures.

A low IQ level does not entail the presence of extended epileptogenic regions or multiple epileptic foci. Seizure-relief rates in our group concurred with the rates in patients of average intelligence, and the cognitive/socioeconomic outcome was favorable. We conclude that focal surgery in intellectually impaired patients can be recommended if the preoperative diagnostics confirm a circumscribed seizure onset.