Page 167 - MEGIN Book Of Abstracts - 2023

Magnetoencephalography Imaging Reveals Keywords: atlas-based connectivity, epilepsy, magnetoen-
Abnormal Information Flow in Temporal Lobe cephalography, phase-transfer entropy
Epilepsy (2022)
Brain connectivity (2022), Vol. 12, No. 4 (34210170) (2
Kudo, Kiwamu; Morise, Hirofumi; Ranasinghe, Kamalini citations)
G; Mizuiri, Danielle; Bhutada, Abhishek S; Chen, Jessie;
Findlay, Anne; Kirsch, Heidi E; Nagarajan, Srikantan S
Evaluation of Brain Network Properties in Patients
Medical Imaging Business Center, Ricoh Company Ltd., with MRI-Negative Temporal Lobe Epilepsy: An MEG
Kanazawa, Japan; Memory and Aging Center, Department Study (2021)
of Neurology, University of California, San Francisco, San
Francisco, California, USA; Biomagnetic Imaging Laboratory, Li, Yuejun; Zhu, Haitao; Chen, Qiqi; Yang, Lu; Bao, Xincai;
Department of Radiology and Biomedical Imaging, Univer- Chen, Fangqing; Ma, Haiyan; Xu, Honghao; Luo, Lei;
sity of California, San Francisco, San Francisco, California, Zhang, Rui
USA; Epilepsy Center, Department of Neurology, University of
California, San Francisco, San Francisco, California, USA Department of Magnetoencephalography, Affiliated Nanjing
Brain Hospital, Nanjing Medical University, Nanjing, 210029,
ABSTRACT Background/Introduction: Widespread net- Jiangsu, China; Department of Functional Neurosurgery,
work disruption has been hypothesized to be an impor- Affiliated Nanjing Brain Hospital, Nanjing Medical University,
tant predictor of outcomes in patients with refractory Nanjing, 210029, Jiangsu, China; Library of Xinxiang Medical
temporal lobe epilepsy (TLE). Most studies examining University, Xinxiang, 453003, Henan, China; Department of
functional network disruption in epilepsy have largely Functional Neurosurgery, Affiliated Nanjing Brain Hospital,
focused on the symmetric bidirectional metrics of the Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
strength of network connections. However, a more [email protected]
complete description of network dysfunction impacts
in epilepsy requires an investigation of the potentially ABSTRACT Abnormal functional brain networks of
more sensitive directional metrics of information flow. temporal lobe epilepsy (TLE) patients with structural
Methods: This study describes a whole-brain magneto- abnormalities may partially reflect structural lesions
encephalography-imaging approach to examine rest- rather than either TLE per se or functional compensa-
ing-state directional information flow networks, quanti- tory processes. In this study, we sought to investigate
fied by phase-transfer entropy (PTE), in patients with the brain-network properties of intractable TLE patients
TLE compared with healthy controls (HCs). Associations apart from the effects of structural abnormalities.
between PTE and clinical characteristics of epilepsy The brain network properties of 20 left and 23 right
syndrome are also investigated. Results: Deficits of in- MRI-negative TLE patients and 22 healthy controls
formation flow were specific to alpha-band frequencies. were evaluated using magnetoencephalographic
In alpha band, while HCs exhibit a clear posterior-to-an- recordings in six main frequency bands. A slowing of
terior directionality of information flow, in patients with oscillatory brain activity was observed for the left or
TLE, this pattern of regional information outflow and in- right TLE group vs. healthy controls. The TLE groups
flow was significantly altered in the frontal and occipital presented significantly increased functional connec-
regions. The changes in information flow within the tivity in the delta, theta, lower alpha and beta bands,
alpha band in selected brain regions were correlated and significantly greater values in the normalized
with interictal spike frequency and duration of epilepsy. clustering coefficient and path length, and significantly
Conclusions: Impaired information flow is an important smaller values in the weighted small-world measure
dimension of network dysfunction associated with the in the theta band when compared to healthy controls.
pathophysiological mechanisms of TLE. Alterations in global and regional band powers can be
attributed to spectral slowing in TLE patients. The brain

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