Literature Review

Stimulation-identified Cortical Naming Sites Pose Unexpected Challenges

Because word production may involve more than one region of the brain, presurgical electrical stimulation mapping may be misleading


 

Before surgeons perform a resection involving the language-dominant hemisphere of a patient with epilepsy, they may do electrical stimulation mapping to identify a patient’s language-dominant hemisphere. Typically they will ask patients to identify objects to help locate the language cortex and then avoid resection in an area of the brain in which electrical stimulation makes it difficult for patients to name said objects. But because word production involves mechanisms that may be centered in more than one area of the brain, Hamberger et al tested locations that have been identified by stimulation as naming sites to look for disparities. Testing patients with refractory temporal lobe epilepsy who had subdural electrodes implanted, they discovered that stimulating naming sites in the superior temporary lobe was more likely to disrupt phonological processing but did not affect a patient’s ability to process semantic information. Stimulating the inferior temporal naming sites was more likely to impair semantic processing.

Hamberger MJ, Miozzo M, Schevon CA, et al. Functional differences among stimulation-identified cortical naming sites in the temporal region. Epilepsy Behav. 2016;60:124-129.

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