Intraoperative Cortical Mapping for Epilepsy Surgery: Advances, Challenges, and Clinical Insights

Abstract

Cortical mapping has revolutionized the field of neurosurgery by enabling precise identification of functional brain regions responsible for essential motor, sensory, language, and cognitive processes. Initially developed to minimize postoperative deficits in brain surgeries, cortical mapping has become particularly valuable in the treatment of drug-resistant epilepsy—a condition where antiepileptic medications fail to provide adequate seizure control. Not only in identifying nerve injury during the surgery, but also in providing functional brain region information involved in epileptic zone affect in preoperative neuronavigation, creating a new gold standard. Neuromonitoring provides a more inexpensive tool of identification compared to functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI).  For such patients, surgical resection of epileptogenic tissue offers a promising path toward improved quality of life, but success hinges on the ability to map functional regions accurately to prevent unintended damage to functional areas. Epilepsy affects millions globally, with many patients experiencing debilitating seizures that impair daily functioning. A multitude of cortical mapping strategies reveals efficacy in identifying epileptogenic zones, spasms, and eloquent cortices by use of single pulse electrical stimulation, recording of the bereitschaftspotential, awake craniotomy paired with direct electrical stimulation, and Electrical Corticography (ECoG). Intraoperative cortical mapping can provide real time insight in changing the surgical resection plan for patients undergoing awake craniotomy. This literature review seeks to examine the current landscape of cortical mapping in epilepsy surgery, analyze the effectiveness of various techniques, and highlight emerging challenges and future directions to improve its accessibility and precision in neurosurgical practice.