Predicting Memory Decline Following Epilepsy Surgery: A Multivariate Approach

Abstract

Summary:Background: While some patients experience a decline in memory function following an anterior temporal lobe resection, there is considerable individual variation in the extent, nature, and direction of postoperative memory change. Patients with surgically remediable temporal lobe epilepsy differ in etiology, the extent and type of underlying pathology, and on demographic and epilepsy-related variables, all of which may have an impact on their pre-and postoperative neuropsychological functioning. This study examined the relationship between these variables and postoperative memory decline.Methods: Logistic regression was used to examine the effects of age, laterality of surgery, age of onset of epilepsy, underlying pathology and preoperative level of memory function on postoperative verbal learning in 288 patients who had undergone an anterior temporal lobe resection. One hundred twenty-five patients underwent a right temporal lobe resection (RTL), 163 patients underwent a left temporal lobe resection (LTL). Results:In the group as a whole, 25% of the patients demonstrated a significant postoperative deterioration in verbal learning. Postoperative deterioration in verbal learning was significantly associated with higher levels of preoperative function in both the RTL and LTL groups. Older age at the time of the operation and a lower verbal IQ were additional significant predictors for the RTL group. The presence of cortical dysgenesis was a significant predictor of postoperative decline in the LTL group. The logistic regression models accurately identified 3/4 of those who experienced a postoperative decline in memory, using a cutoff of 0.25 or above to identify high risk.Conclusions: Our analyses suggest that the majority of patients with a high risk of significant postoperative memory decline can be reliably identified preoperatively. These models are valuable tools helping patients make an informed decision regarding surgery.

What do patients with epilepsy tell us about language dynamics? A review of fMRI studies

“…There is also evidence that an EZ in or near the hippocampal region but distant from temporal language regions may modulate the lateralization of language representation Hamberger et al, 2007). Compared with patients without HS, patients with HS are more likely to show atypical hemispheric lateralization of language (Pataraia et al, 2004;Powell et al, 2008;Labudda et al, 2010;Richardson, 2010) and have better language functioning (Chelune et al, 1991;Hermann et al, 1995;Davies et al, 1998;Stroup et al, 2003;Gleissner et al, 2004;Baxendale et al, 2006;Lineweaver et al, 2006). As suggested by Knecht (2004), the hippocampus may be crucial to the implementation of hemispheric lateralization for language, and frontotemporal language network functioning may be altered if the hippocampus is injured.…”

Prediction of neuropsychological outcome after resection of temporal and extratemporal seizure foci

“…30 The latter finding is presumed to reflect reduced plasticity or lower compensatory reserve in older adults. 1 Finally, individuals with moderate depressive symptoms before surgery are at greater risk of verbal memory decline following left ATR; this finding is hypothesized to reflect reduced compensatory reserve.…”

Five-Year Neuropsychological Outcome after Stereotactic Radiofrequency Amygdalohippocampectomy for Mesial Temporal Lobe Epilepsy: Longitudinal Study

“…However, a risk of further material-specific memory decline, especially after operations on the language-dominant temporal lobe, has been consistently reported as a side effect of resections [10,11]. Visual memory deficit has profound adverse effects on patients' quality of life [12].…”