Cognitive Changes after Resective Surgery for Medical Refractory Temporal Epilepsy in Relation to the Side of Surgery

Overview

Goal:
The presentation assesses the relationship of the postsurgery cognitive changes to the side of surgery.

Methods:
In the sample of 41 adult patients (18 left-sided surgery, 23 right -sided), intelligence was evaluated by WAIS-R, memory by WMS-R (in a few patients by WMS). We used a comparison of average values of groups and three methods of reliable change indices (RCI) in individuals (Franzen, Iverson, 2000): standard deviation (±SD), and two methods of reliable difference scores by Chelune et al. (1993) and by Atkinson (1991).

Results:
There were no significant differences between groups in cognitive functions before surgery. On the average 19.7 months after surgery, patients with left-sided surgery have significantly lower general memory than patients with right-sided surgery (p=0.009). The average change between pre- and postsurgical general memory is negative, e.i. worsening (-5.88) in left-sided surgery, and positive, e.i. improving (6.22) in right-sided surgery (p=0.001). In left-sided surgery, 17 patients were evaluated by memory test out of whom, after surgery, 3 patients’ (17.6%) memory declined more than 1 SD. In the right-sided surgery, 23 patients were evaluated, out of whom, after surgery, 6 patients (26.1%) improved more than 1 SD, 1 patient (4.4%) declined more than 1 SD.

Conclusion:
Evaluation of neuropsychological changes relates to efforts to improve patients’ quality of life, dependent not only on epileptological efficiency of surgery, but also on changes in cognitive, especially memory functioning, which are possible after surgery.

Key words:
epilepsy, neurosurgery, cognitive changes-memory, neuropsychology, reliable change indices (RCI).