Electrocortical Mapping of Language

Cortical mapping for identification of language eloquent cortex is common in epilepsy and tumor surgical centers. This chapter provides a brief history of electrocortical language mapping in the context of a planned surgical resection and then focuses on the pragmatics of knowing why, when, and how to perform this procedure both at the bedside and in the operating room. We summarize the indications for language mapping, pre-mapping procedures, stimulation parameters, general parameters for language testing, types of language tasks that can be used, scoring procedures, methods for separating motor from language effects, and performing mapping in special populations. In addition, we highlight a number of potential pit falls, complications, and logistical challenges that can occur during this procedure. Finally, using a case example, we illustrate how we perform a language mapping procedure at our center. While there is certainly variance in how this procedure is performed across surgical centers, we provide specific pros and cons for many of the standard techniques that are widely used. Regardless of the specific procedures used, we have found that using an integrated multidisciplinary approach that takes advantage of the skill sets and specialized knowledge that neurologists, neurosurgeons, and neuropsychologists bring to the table provides the best outcome.