A technique for mapping cortical areas associated with speech arrest

Background: Awake craniotomy with cortical stimulation is the standard for language mapping in patients with tumors near or within the language cortex. Reliable identification of the speech cortex is difficult, however, and adjunctive pre- and intraoperative techniques have inconsistent reliability. Objectives: We describe a technique based on direct cortical stimulation which localizes speech areas by correlating vocal cord activation in the anesthetized patient with speech arrest in the awake patient. Methods: Direct cortical stimulation is applied to the patient and the vocal cords are visualized by fiberoptic endoscopy. The cortical site that produces vocal cord activation is identified. Once the patient is awakened, cortical stimulation is repeated and sites that produce speech arrest are identified. Results: We have performed this technique in 3 patients and have consistently correlated vocal cord activation with speech arrest in all patients. These areas of activation also correlate with areas of functional MRI BOLD activation obtained from the expressive language paradigms. Conclusions: Colocalization of the site of vocal cord activation in the asleep patient to the site of speech arrest in the awake patient represents an adjunct for defining speech areas. This technique is useful for patients unable to tolerate awake craniotomy.