AUTHOR=Lin Yicong , Zhang Zhiguo , Zhang Xiating , Yang Yingxue , Huang Zhaoyang , Zhu Yu , Li Liping , Hu Ningning , Zhang Junpeng , Wang Yuping 

TITLE=Lateralization Value of Low Frequency Band Beamformer Magnetoencephalography Source Imaging in Temporal Lobe Epilepsy

JOURNAL=Frontiers in Neurology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2018.00829

DOI=10.3389/fneur.2018.00829

ISSN=1664-2295

ABSTRACT=<p><bold>Objective:</bold> In presurgical evaluation of temporal lobe epilepsy (TLE), selection of the resection side is challenging when bilateral temporal epileptiform discharges or structural abnormalities are present. We aim to evaluate the lateralization value of beamformer analysis of magnetoencephalography (MEG) in TLE.</p><p><bold>Methods:</bold> MEG data from 14 TLE patients were analyzed through beamformer analysis. We measured the hemispherical power distribution of beamformer sources and calculated the lateralization index (LI). We calculated the LI at multiple frequencies to explore the frequency dependency and at the delta frequency to define laterality. LI values ranging from −1 to −0.05 indicated right hemispheric dominance. LI values ranging from 0.05 to 1 indicated left hemispheric dominance. LI values ranging from −0.05 to 0.05 defined bilaterality. We measured the power of beamformer sources with a 9-s duration to explore time dependency.</p><p><bold>Results:</bold> The beamformer analysis showed that 10/14 patients had power dominance ipsilateral to resection. The delta frequency band had a higher lateralization value than other frequency bands. A time-dependent power fluctuation was found in the delta frequency band.</p><p><bold>Conclusions:</bold> MEG beamformer analysis, especially in the delta band, might efficiently provide additional information regarding lateralization in TLE.</p>