Page 198 - MEGIN Book Of Abstracts - 2023

METHODS Clinical and MEG data were analyzed waukee, USA. Electronic address: [email protected]; Depart-
for 121 children with TL and TL+ epilepsy spanning ment of Neurology, Medical College of Wisconsin, Milwaukee,
20 years at the Hospital for Sick Children. Resting-state USA. Electronic address: [email protected]; Department of
connectomes were derived using the weighted phase Neurology, Medical College of Wisconsin, Milwaukee, USA.
lag index from neuromagnetic oscillations. Multidi- Electronic address: [email protected]; Department of Neurol-
mensional associations between patient connectomes, ogy, Medical College of Wisconsin, Milwaukee, USA. Electronic
TL versus TL+ epilepsy, seizure freedom, and clinical address: [email protected]; Department of Neurology,
covariates were performed using a partial least squares Medical College of Wisconsin, Milwaukee, USA. Electronic
(PLS) analysis. Bootstrap resampling statistics were address: [email protected]; Department of Neurology,
performed to assess statistical significance. Medical College of Wisconsin, Milwaukee, USA. Electronic ad-
dress: [email protected]; Department of Neurology, Medical
RESULTS A single significant latent variable represent- College of Wisconsin, Milwaukee, USA. Electronic address:
ing 66% of the variance in the data was identified with [email protected]
significant contributions from extent of epilepsy (TL vs
TL+), duration of illness, and underlying etiology. This ABSTRACT Evaluation of language dominance is an
component was associated with significant bitemporal essential step prior to epilepsy surgery. There is no
and frontotemporal connectivity in the theta, alpha, consensus on an optimal methodology for determining
and beta bands. By extracting a brain score, represen- language dominance using magnetoencephalography
tative of the observed connectivity profile, patients (MEG). Oscillatory dynamics are increasingly recognized
with TL epilepsy were dissociated from those with TL+, as being of fundamental importance for brain function
independent of their postoperative seizure outcome. and dysfunction. Using task-related beta power modu-
lations in MEG, we developed an analysis framework for
SIGNIFICANCE By analyzing 121 connectomes derived localizing and lateralizing areas relevant to language
from MEG data using a PLS approach, we find that processing in patients with focal epilepsy. We examined
connectomic profiling could dissociate TL from TL+ MEG responses from 29 patients (age 42 ± 13 years,
epilepsy. These findings may inform patient selection 15M/14F) during auditory description naming (ADN)
for resective procedures and guide decisions surround- and visual picture naming (PN). MEG data were prepro-
ing invasive monitoring. cessed using a combination of spatiotemporal filtering,
signal thresholding, and ICA decomposition. Beta-band
Keywords: epilepsy, functional connectivity, neuroimag- 17-25Hz power decrements were examined at both
ing, oscillations, phase-locking sensor and source levels. Volumetric grids of anatomi-
cal source space were constructed in MNI space at 8
Epilepsia (2020), Vol. 61, No. 8 (32619065) (10 citations) mm isotropic resolution, and beta-band power changes
were estimated using the dynamic imaging of coherent
sources beamformer technique. A 600 ms temporal-
Mapping language from MEG beta power window that ends 100 ms before speech onset was
modulations during auditory and visual naming selected for analysis, to focus on later stages of word
(2020) production such as phonologic selection and motor
speech preparation. Cluster-based permutation testing
Youssofzadeh, Vahab; Stout, Jeffrey; Ustine, Candida; was employed for patient- and group-level statistical
Gross, William L; Conant, Lisa L; Humphries, Colin J; inferences. Automated anatomic labeling atlas-driven
Binder, Jeffrey R; Raghavan, Manoj laterality indices (LIs) were computed for 13 left and
right language- and motor speech-related cortical
Department of Neurology, Medical College of Wisconsin, Mil- regions. Group localization of ADN and PN consistently
waukee, USA. Electronic address: [email protected]; revealed significant task-related decrements of beta-
Department of Neurology, Medical College of Wisconsin, Mil- power within language-related areas in the frontal,

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