Abstract Details

Title Combining fMRI Language Lateralization and Hippocampal Morphometry for Predicting Verbal Memory Outcome after Left Temporal Lobectomy

Topic Epilepsy/Clinical Neurophysiology (EEG)

Presentation(s) S28 - (-)

Poster/Presentation
Number 003

Objective

Background Verbal memory decline is frequent after L-ATL and can be predicted with fair accuracy using an fMRI index of language lateralization. Here, we investigated the predictive value of hippocampal morphometry alone and in conjunction with fMRI.

Design/Methods Participants were 66 left temporal lobe epilepsy patients treated with L-ATL. All patients underwent preoperative fMRI using a semantic decision - tone decision contrast to measure language lateralization. All patients had preoperative and 6-month postoperative verbal memory testing, including a word-list learning and retention measure (Selective Reminding Test) and a story recall test (Wechsler Logical Memory). T1-weighted preoperative MRI scans were analyzed with FreeSurfer software to create automated initial parcellations of the hippocampus, which were then manually edited based on standard landmarks.

Results Unlike fMRI language lateralization, the hippocampal volume measures provided no additional value for predicting postoperative change on the word-list learning test. In contrast, hippocampal volume was superior to fMRI for predicting change on the story memory test, with larger left hippocampal volume (r = -.361, p = .003) and smaller rightward hippocampal asymmetry (r = -.259, p = .037) correlating with greater decline in performance. Left hippocampal volume remained an independent predictor of story memory change after including fMRI and preoperative performance in a multivariate regression model (R2 change = .075, p = .027).

Conclusions Preoperative left hippocampal volume was predictive of postoperative change on a story recall task, whereas rote word-list learning was linked more closely to language lateralization. Encoding of meaningful stories likely engages bihemispheric semantic networks that are partially independent of the language system. Hippocampal morphometry adds predictive value for risk assessment prior to L-ATL surgery.

Authors/Disclosures
Patrick M. Bauer, MD (FROEDTERT NORTH HILLS HEALTH CENTER) PRESENTER	No disclosure on file
	No disclosure on file
David Sabsevitz	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
Manoj Raghavan, MD, PhD (Medical College of Wisconsin)	No disclosure on file
Anthony Traboulsee, MD (University of British Columbia)	Dr. Traboulsee has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Roche. Dr. Traboulsee has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi. Dr. Traboulsee has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi. Dr. Traboulsee has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi. Dr. Traboulsee has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for EMD Serono. Dr. Traboulsee has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Roche. The institution of Dr. Traboulsee has received research support from Roche. The institution of Dr. Traboulsee has received research support from Genzyme. The institution of Dr. Traboulsee has received research support from Consortium of MS Centers. The institution of Dr. Traboulsee has received research support from MS Canada. Dr. Traboulsee has received personal compensation in the range of $500-$4,999 for serving as a Workshop Chair with Consortium of MS Centers.
	No disclosure on file
Jeffrey Binder, MD (Medical College of Wisconsin)	No disclosure on file

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