Elisabeth Engman

Group versus individual verbal and visuospatial memory outcome following epilepsy surgery was evaluated by a non-parametric method in 25 left and 29 right temporal lobectomy patients. Twenty-five controls were assessed twice. Analyses of change at an individual level evaluated by this statistical approach based on paired-ranks were compared to results with a method based on distances (Reliable Change). The left temporal lobectomy group deteriorated in the two verbal memory variables (p < 0.01 and 0.05). High levels of individual changes unexplained by group patterns were disclosed in the three memory variables analyzed in the patients. Significant individual change, although less pronounced, also occurred in the controls. Group versus individual outcome was adequately distinguished by the non-parametric method. To properly analyze memory change after epilepsy surgery, evaluation at group and individual level ought to combined.

To describe cognitive function preoperatively and cognitive change 2 years postoperatively in 70 consecutive adults in the Göteborg epilepsy surgery series. Analysis of general neurocognitive status and memory for the total group and for three subgroups: 26 patients with seizure onset in dominant temporal lobe, 28 patients with onset in non-dominant temporal lobe and 12 with frontal lobe onset. Preoperative performance was compared with a control group (n=30). Preoperatively, patients were more impaired in general neurocognitive status than controls. Patients in the temporal lobe subgroups performed worse than controls in two memory variables. No postoperative negative change was found at group level. There was a small increase in Full Scale IQ and Performance IQ for the total patient group, and in Performance IQ for the frontal lobe subgroup. At individual level, many patients suffered losses or obtained gains in a number of memory variables without any consistent intra-pattern. Cognitive stability was the main postoperative result. The importance of considering inter- and intra-individual variability of negative as well as positive change is emphasized.