Abstracts

Several investigations have shown an association between Wada memory performance before surgery and material-specific (verbal and visuospatial) memory outcome after surgery on a group level in adult epilepsy surgery patients. There continues to be uncertainty whether these results are applicable to children, and the degree to which Wada memory results may be used to predict memory decline in the individual patient. Thus, we examined the capacity of Wada memory asymmetries to predict postoperative memory decline in children undergoing epilepsy surgery using both group and individual levels of analyses.
Seventy-five children who underwent Wada memory evaluation in both hemispheres, and who subsequently underwent some form of resective epilepsy surgery, served as subjects. Children were classified into one of two groups: 1) Wada Asymmetry group = memory after injection ipsilateral to the side of surgery was greater than memory after contralateral injection, or 2) No Asymmetry group = Wada memory after ipsilateral injection was less than or equal to memory after contralateral injection. There were no significant differences between groups with regard to age, handedness, gender, duration of seizure disorder, side of surgery, location (TL vs. ExTL) of surgery, IQ, preoperative verbal memory, preoperative visuospatial memory, or interval between surgery and postoperative memory assessment. Verbal memory was assessed using Children[apos]s Memory Scale (CMS) Stories and visuospatial memory was assessed using either CMS, Visual Delay Index or Rey Complex Figure.
There were significant interaction effects for both verbal (p = .04) and visuospatial (p = .04) memory tests. Verbal and visuospatial memory scores increased after surgery for children with Wada Asymmetries and decreased after surgery in children who showed No Wada Asymmetries. Group differences were also obtained when the number of individual cases showing postoperative memory change was examined. Significantly more children with Wada Asymmetries had improved verbal (74%) and visuospatial (66%) memory scores pre- to post-surgery than children with No Wada Asymmetries. Significantly more children with No Wada Asymmetries had verbal (64%) and visuospatial (87%) memory scores decline after surgery.
Wada memory asymmetries may be used to measure risk of material-specific memory decline in verbal and visuospatial memory functions following epilepsy surgery in children.