Abstract Details

Title Utility of MEG for Functional Language Mapping

Topic Epilepsy/Clinical Neurophysiology (EEG)

Presentation(s) P1 - Poster Session 1 (12:00 PM-1:00 PM)

Poster/Presentation
Number 12-004

Objective This study was performed to determine if Magnetoencephalography (MEG) has adequate predictive value of postoperative language deficits compared to the intracarotid amobarbital procedure (IAP).

Background Epilepsy patients who undergo surgical resections of the dominant temporal lobe are at risk for losing language function. With transient suppression of function, the IAP is used to predict whether resection is likely to lead to language deficits. However, it is invasive with risk of arterial dissection and has issues with test-retest reliability.

Design/Methods 40 patients thought to have localization-related epilepsy underwent both MEG and IAP. Language tasks involving semantic and phonological processing [verb generation (VG) and picture naming (PN)] were performed. MEG data were analyzed by MR-FOCUSS, a current density imaging technique to identify the locations of Wernicke’s and Broca’s activation. A laterality index (LI) was calculated from the MEG solution to determine which hemisphere had more neural activation during these language tasks. Many (N=29) went on to surgery.

Results There was concordance between the IAP and MEG LIs during the PN task in 26 patients (65%), and between IAP and MEG LIs during the VG task in 16 of 22 patients (73%). MEG localization of Broca’s activation during the PN task was concordant with IAP in 18 of 34 patients (53%). MEG localization of Wernicke’s activation during the VG task was concordant with the IAP in 21 of 36 patients (58%). 10% (3/29) of the patients who underwent surgery were noted to have postoperative language deficits.

Conclusions For the patients without intact fluent speech the MEG could provide localization results to guide the resection and improve the surgical outcome.

Authors/Disclosures
PRESENTER	No disclosure on file
Gamaleldin M. Osman, MD (Mayo Clinic)	Dr. Osman has nothing to disclose.
	No disclosure on file
Sarah Madani, MD (Atrius Health)	No disclosure on file
Muhammad O. Salim Khan, DO (Mercy Gilbert Medical Center)	Dr. Salim Khan has nothing to disclose.
Amanda Brown, PhD (Johns Hopkins University School of Medicine)	No disclosure on file
Gregory L. Barkley, MD (Henry Ford Hospital)	No disclosure on file
	No disclosure on file
	No disclosure on file
Susan M. Bowyer, PhD (Henry Ford Hospital)	Dr. Bowyer has nothing to disclose.