Language Localization with Pars Opercularis Stimulation: A Cortico-Cortical Evoked Potential Analysis
Abstract number :
2.043
Submission category :
3. Neurophysiology / 3E. Brain Stimulation
Year :
2021
Submission ID :
1825946
Source :
www.aesnet.org
Presentation date :
12/9/2021 12:00:00 PM
Published date :
Nov 22, 2021, 06:51 AM
Authors :
Kenneth Taylor, PhD - Cleveland Clinic; Krishna Galla – Cleveland Clinic; Anand Joshi – University of Southern California; William Bingaman – Cleveland Clinic; Juan Bulacio – Cleveland Clinic; Richard Leahy – University of Southern California; Dileep Nair – Cleveland Clinic
Rationale: Cortico-cortical evoked potentials (CCEPs) are responses elicited by single pulse electrical stimulation of intracranial electrodes. Stimulation of pairs of SEEG contacts can be employed to evoke measurable signals in both distant and nearby regions as a means of epileptic network analysis. Here we investigate and visualize the strength of connectivity to areas known to be associated with language processing in response to pars opercularis stimulation, in the context of known language lateralization.
Methods: We reviewed 25 patients with medically intractable epilepsy who were implanted with depth electrodes and subsequently underwent CCEPs stimulation as a part of their clinical evaluation prior to surgical intervention. All patients had at least one contact within the pars opercularis and coverage of the frontal, temporal, and parietal lobes. All patients had language lateralization independently confirmed via either fMRI or WADA. Connectivity was assessed by determining the RMS value of the averaged response to stimulation, and then applying a permutation test to the early (10-60ms), late (60-250ms), and very late (250-600ms) periods of the response in order to identify periods of statistical significance. A comparison was then made between the 16 patients with left side language dominance and the 9 patients identified as right side dominant.
Results: The analysis presented here identifies statistically significant periods of response to pars opercularis stimulation. The majority of subjects with left hemispheric language dominance showed significant responses in the supramarginal gyrus, however those with right hemispheric dominance did not. The majority of right hemisphere dominant subjects showed significant responses in the transverse temporal gyrus, this was less common in those with left hemispheric language dominance. The angular gyrus showed no clear connectivity to the pars opercularis in any subject.
Conclusions: The CCEPs RMS and significance measures provide a means to identify hemispheric differences in connectivity patterns from the left pars opercularis. We observe notable differences in connectivity to the supramarginal gyrus and transverse temporal gyrus in the context of language lateralization.
Funding: Please list any funding that was received in support of this abstract.: R01NS089212.
Neurophysiology