Abstracts

Rationale: Visual naming declines occur in 25-60% of adults following dominant anterior temporal lobectomy (ATL). However, few studies have examined naming outcome after other resection types. Study goals were to 1) examine naming outcome following epilepsy surgery as a function of side/site of resection, 2) assess magnitude of postoperative naming decline, and 3) identify factors associated with change (declines or improvements) in postoperative naming ability.Methods: Data were obtained from a neuropsychology registry of adult patients who underwent epilepsy surgery between 1986 and 2012. A total of 783 patients (402 left/381 right; 685 temporal/80 frontal/18 posterior quadrant) met inclusion criteria: IQ 70, pre and postoperative Boston Naming Test scores, right-handed or left hemisphere language dominant per Wada or fMRI, focal resection for epilepsy treatment, and no prior neurosurgery. Patients were classified into naming outcome groups (improved, no change, decline) using reliable change indices ( 5 or more raw points). Chi-square analyses examined differences in naming outcome as a function of surgical resection site, with separate analyses for left and right-sided resections. Magnitude of postoperative decline was examined by categorizing decliners into groups based on degree of change in postoperative naming score (5-10, 11-20, >20 points). Finally, ANOVAs were used to identify factors most associated with naming change.Results: While there was no difference in naming outcome as a function of surgery site in patients with right-sided resections, there was a significant difference following left-sided resections. Naming decline occurred in 36% of patients following left ATL compared to 10-14% in the other surgical groups. A sizable proportion of left ATL patients (14%) showed substantial declines in naming (>11 points). Decline after left ATL was related to later age at seizure onset, higher preoperative naming score, and older age at surgery. These three factors were also associated with the degree of naming decline. In contrast, naming improvements were more common among patients who underwent left frontal resections (21%) than in other left-sided surgical groups (8-14%) and were related to seizure freedom. Among FLE patients with postoperative naming improvements, 89% were seizure-free, whereas all FLE patients with postoperative naming declines continued to have seizures after surgery. Conclusions: Results confirm that naming decline occurs most frequently after left ATL and is associated with later onset age, older age at surgery, and better preoperative naming in these patients. Our findings extend current literature by showing these risk factors are also associated with degree of postoperative naming decline. Interestingly, naming decline was relatively rare following left frontal resection and only occurred with continued seizures. Future studies will explore other potential risk factors for naming decline (e.g., pathology, resection extent) and develop a regression equation to assist clinicians in identifying patients at risk for substantial postoperative naming deficits.