Dynamics of hemispheric dominance for language assessed by magnetoencephalographic imaging
Article first published online: 20 APR 2012
Copyright © 2012 American Neurological Association
Annals of Neurology
Volume 71, Issue 5, pages 668–686, May 2012
How to Cite
Findlay, A. M., Ambrose, J. B., Cahn-Weiner, D. A., Houde, J. F., Honma, S., Hinkley, L. B. N., Berger, M. S., Nagarajan, S. S. and Kirsch, H. E. (2012), Dynamics of hemispheric dominance for language assessed by magnetoencephalographic imaging. Ann Neurol., 71: 668–686. doi: 10.1002/ana.23530
- Issue published online: 20 APR 2012
- Article first published online: 20 APR 2012
- Accepted manuscript online: 12 JAN 2012 11:15PM EST
- Manuscript Revised: 22 DEC 2012
- Manuscript Received: 23 JUN 2012
- Manuscript Accepted: 9 JAN 2012
- NIH. Grant Numbers: R01DC004855, R01DC006435, R21NS076171, UL1 RR024131
- National Science Foundation. Grant Number: BCS0926196
- UCSF Research Evaluation and Allocation
- Epilepsy Foundation Fellowship
The goal of the current study was to examine the dynamics of language lateralization using magnetoencephalographic (MEG) imaging, to determine the sensitivity and specificity of MEG imaging, and to determine whether MEG imaging can become a viable alternative to the intracarotid amobarbital procedure (IAP), the current gold standard for preoperative language lateralization in neurosurgical candidates.
MEG was recorded during an auditory verb generation task and imaging analysis of oscillatory activity was initially performed in 21 subjects with epilepsy, brain tumor, or arteriovenous malformation who had undergone IAP and MEG. Time windows and brain regions of interest that best discriminated between IAP-determined left or right dominance for language were identified. Parameters derived in the retrospective analysis were applied to a prospective cohort of 14 patients and healthy controls.
Power decreases in the beta frequency band were consistently observed following auditory stimulation in inferior frontal, superior temporal, and parietal cortices; similar power decreases were also seen in inferior frontal cortex prior to and during overt verb generation. Language lateralization was clearly observed to be a dynamic process that is bilateral for several hundred milliseconds during periods of auditory perception and overt speech production. Correlation with the IAP was seen in 13 of 14 (93%) prospective patients, with the test demonstrating a sensitivity of 100% and specificity of 92%.
Our results demonstrate excellent correlation between MEG imaging findings and the IAP for language lateralization, and provide new insights into the spatiotemporal dynamics of cortical speech processing. ANN NEUROL 2012;