Predicting post-surgical visuospatial memory performance in people with drug-resistant epilepsy

Although verbal memory decline has been consistently reported following surgery for temporal lobe epilepsy, especially when surgery is performed in the language-dominant hemisphere and targets mesial temporal structures, the relation between the location and the hemisphere of surgery on visuospatial memory, as well as the factors predicting visuospatial memory decline, remains less clear. This study first examines the impact of epilepsy surgery location and laterality on visuospatial and verbal memory performance and then explores the predictors of memory change following surgery.

We retrospectively collected data from 75 individuals who completed the Brief Visuospatial Memory Test-Revised and the Rey Auditory Verbal Learning Test as part of their pre- and post-surgical neuropsychological assessments at our center.

Surgery for mesial temporal lobe epilepsy in the dominant hemisphere was associated with poorer performance on all memory outcomes, whereas mesial temporal lobe epilepsy surgery in the non-dominant hemisphere selectively impaired delayed recall of visuospatial material. A presurgical memory profile combining better visuospatial memory and poorer verbal memory, and the recurrence of seizures after surgery, best predicted visuospatial memory decline after the procedure, whereas verbal memory decline was predicted by better preoperative verbal memory performance in addition to surgery in the dominant hemisphere.

These findings emphasize the relevance of considering presurgical visuospatial and verbal memory performance when attempting to predict visuospatial memory decline following surgery. Limitations to our study include potential selection bias, variability in testing parameters, and a relatively small sample size.