Cortical language mapping using electrical cortical stimulation for Mandarin-speaking patients with epilepsy: A report of six case studies

Abstract

Objective The goal of this study was to summarize the results of language cortex mapping using electrical cortical stimulation with modified language tasks for Mandarin-speaking patients with epilepsy. Methods Electrical currents were delivered through implanted subdural electrodes to six Mandarin-speaking patients before epilepsy surgery. The current intensities inducing any language disturbance during comprehension, repetition, and speech tasks were recorded, and individual cortical mapping was completed to guide subsequent resection, with the distance between mapped language sites and resected zones kept at a minimum of 0.5 cm. Language function was reassessed and followed up after surgery. Results Language cortices were successfully identified in three patients, but demonstrated great variability in distribution. There seemed to be no difference in the intensity threshold that induced language interference. None of the six patients exhibited language deficits postsurgery. Conclusions Electrical cortical stimulation with modified language tasks is valid for identification of cortices underlying Mandarin processing. The great variability in language cortex distribution enhances the necessity of individual language cortical mapping in epilepsy surgery.