Abstracts

Epileptic patients undergoing left temporal lobe surgery for seizure control are at particular risk of postoperative verbal memory decline. The question of this study was as to whether this risk is minimized in the presence of atypical language dominance.
Pre- and one year postoperative memory performance was evaluated in 169 patients (92men/77women) who underwent left temporal lobe surgery and who had WADA testing prior to surgery. Verbal memory was assessed by word- list learning paradigm (VLMT). Patients were categorized into a left dominant, bilateral, and right language dominant group according to the Bonn IAT protocol (Brain&Language,48,1994). Results were controlled for reasonable sex differences.
More women (48%) than men (31%) had patterns of atypical language dominance. Seizure outcome was better for men (65% completely seizure free) than for women (48%) and was controlled in subsequent analyses. ANOVA for preoperative measures revealed a significant [acute]sex X dominance[acute] interaction, in that atypically dominant women showed better verbal memory than typically dominant women or men. Repeated measurement ANOVA revealed a significant interaction effect of [acute]surgery X language dominance[acute] indicating that right dominant patients had better verbal memory outcome than patients with bilateral or left language dominance who showed significant memory loss. No effect of sex on memory change was obtained.
Better preserved verbal memory in atypically dominant women before surgery indicates greater profit from atypical dominance in woman than men with regard to the initial damage associated with epilepsy. Later in life no such sex difference is observed indicating that this advantage is fixed to an early time window. For clinical practice it is important to note that only complete right hemisphere language dominance may protect against verbal memory loss after left sided temporal lobe surgery.