Predicting memory change after temporal lobectomy for epilepsy

Anterior temporal lobectomy is an accepted and effective treatment for medically resistant seizures. Anterograde verbal memory decline is a common and potentially debilitating morbidity associated with (typically language-dominant) temporal lobectomy.¹ In this issue of Neurology®, Sidhu et al.² have described a functional MRI (fMRI) method that predicts memory change following temporal lobectomy. Review of their data table shows a strong correlation between their memory Lateralization Index (LI) and regression-adjusted change in ability to learn a supraspan word list over serial presentations. Their statistical analysis demonstrated that the LI was the best predictor of change compared to volume of the resected hippocampus, age at onset, duration, and other factors. This group of investigators previously reported a similar finding for a different fMRI technique,³ and their current fMRI method demonstrates involvement of frontal networks in verbal learning that appear useful in predicting postsurgical memory change.