Intraoperative Identification and Preservation of Verbal Memory in Diffuse Gliomas: A Matched-Pair Cohort Study

Recent glioma surgery series with intraoperative electrical stimulation (IES) language mapping have demonstrated high rates of postoperative memory impairment, raising a question regarding the efficacy of this approach to preserve memory.

To evaluate if intraoperative identification and preservation of verbal memory sites with IES mapping in diffuse gliomas in eloquent areas consistently protect patients from long-term postoperative decline in short-term memory.

A cohort of 16 subjects with diffuse low-grade or anaplastic gliomas that were operated with IES and intraoperative evaluation of language and verbal memory (cohort A) was matched by tumor side, pathology, and radiotherapy with a cohort of 16 subjects that were operated with IES and evaluation of language (cohort B). Detailed neuropsychological assessment was performed before and 6 mo after surgery.

Intraoperative memory mapping was a strong predictor of verbal memory prognosis. In cohort A, 4 patients (26.7%) had a decline of at least one of the 4 short-term memory tests evaluated. In cohort B, 11 patients (73.3%) had a decline of at least one of the 4 tests. This difference was statistically significant in multivariate analysis (P = .022; odds ratio = 9.88; 95% confidence interval = 1.39-70.42).

Verbal memory areas identified intraoperatively with the current paradigm are critically involved in verbal memory, as memory impairment can be significantly reduced by adapting the resection to avoid those memory areas. Incorporation of verbal memory evaluation in stimulation mapping protocols might assist in reducing postoperative sequelae and preserving the patient's quality of life.