Global and regional functional connectivity maps of neural oscillations in focal epilepsy

Englot, Dario J.; Hinkley, Leighton B.; Kort, Naomi S.; Imber, Brandon S.; Mizuiri, Danielle; Honma, Susanne; Findlay, Anne; Garrett, Coleman; Cheung, Paige L.; Mantle, Mary; Tarapore, Phiroz E.; Knowlton, Robert C.; Chang, Edward F.; Kirsch, Heidi E.; Nagarajan, Srikantan S.

doi:10.1093/brain/awv130

Cited by 202 publications

(201 citation statements)

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“…They found a positive predictive value for an Engel's class Ia outcome in 70 % of the patients who had high coherence in the area of the later resection. More recently [13] looked at the regional and global functional connectivity of MEG coherence in patients with Epilepsy, based on a 1 min resting state scan. This study used a beamforming technique to image the underlying sources.…”

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confidence: 99%

Coherence a measure of the brain networks: past and present

Bowyer

2016

Neuropsychiatr Electrophysiol

252

178

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Brian connectivity describes the networks of functional and anatomical connections across the brain. The functional network communications across the brain networks dependent on neuronal oscillations. Detection of the synchronous activation of neurons can be used to determine the wellbeing or integrity of the functional connectivity in the human brain networks. Well-connected highly synchronous functional activity can be measured by Electroencephalography (EEG) or Magnetoencephalography (MEG) and then analyzed with several types of mathematical algorithms. Coherence is one mathematical method that can be used to determine if two or more sensors, or brain regions, have similar neuronal oscillatory activity with each other. Since the 1960's, coherence has generally been assessed on the similarity of the frequency content across EEG sensors. Recently coherence, after it has been imaged in the brain, has been used to assess how coherent or connected specific locations in the brain are networked together in several different neurological disorders. Statistical analysis can then be performed on the coherence results to verify evidence of normal or abnormal network activity in a patient. In this review we highlight how functional brain connectivity is assessed in Source space using coherence technique measured by MEG.

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confidence: 99%

Coherence a measure of the brain networks: past and present

Bowyer

2016

Neuropsychiatr Electrophysiol

252

178

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“…Keller et al (2015) demonstrated that patients with mesial temporal lobe epilepsy with persistent seizures who underwent amygdalohippocampectomy had significant atrophy of the bilateral dorsomedial and pulvinar thalamic regions. They also found that patients with persistent seizures had alterations of DTI-derived thalamotemporal probabilistic paths bilaterally, relative to those patients who were rendered seizure-free (Englot et al, 2015;Keller et al, 2015;Xu et al, 2014). Another study demonstrated that patients with unsuccessful surgical outcomes in mesial temporal lobe epilepsy demonstrated larger interhemispheric voxel-mirrored homotropic connectivity differences than those patients with successful surgical outcomes (Xu et al, 2014).…”

Section: Discussionmentioning

confidence: 96%

“…Another study demonstrated that patients with unsuccessful surgical outcomes in mesial temporal lobe epilepsy demonstrated larger interhemispheric voxel-mirrored homotropic connectivity differences than those patients with successful surgical outcomes (Xu et al, 2014). Moreover, a magnetoencephalography study revealed that patients with increased regional connectivity within the resection T A B L E 3 Results of multivariate analysis of variables that are predictive of a poor response to antiepileptic drugs site were more likely to achieve postoperative seizure freedom than those with neutral or decreased regional connectivity in focal epilepsy (Englot et al, 2015). These previous studies have suggested that brain connectivity can be a potential biomarker for predicting responses to epilepsy treatment.…”

Section: Discussionmentioning

confidence: 98%

Can we predict drug response by volumes of the corpus callosum in newly diagnosed focal epilepsy?

Kim

Lee

et al. 2017

Brain and Behavior

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Objective: The aim of this study was to investigate whether volumes of the corpus callosum could predict a response to antiepileptic drugs in patients with newly diagnosed focal epilepsy. Methods:Fifty-three patients with newly diagnosed focal epilepsy of unknown etiology and healthy subjects were enrolled in this study. First, we analyzed the differences in the volumes of the corpus callosum between patients with epilepsy and healthy subjects. Second, we divided patients with epilepsy into antiepileptic drug responders and drug nonresponders groups, according to their seizure controls, and evaluated the differences in the volumes of the corpus callosum between the groups. Third, we conducted correlation analyses between the volumes of the corpus callosum and mean diffusion measures in healthy subjects. Results:The volumes of the corpus callosum in patients with epilepsy were significantly lower than those in normal controls (p = .0001). Among epilepsy patients, the volumes of the corpus callosum were significantly lower in antiepileptic drug responders compared with nonresponders (p = .0481), which was the only independent variable for predicting antiepileptic drug response (OR = 10.07, p = .0434). In addition, we found that the volumes of the corpus callosum were significantly correlated with the mean diffusion measures (fractional anisotropy, r = .408, p = .0027; mean diffusivity, r = −0.403, p = .0028) in normal controls. Conclusions:We demonstrated that the volumes of the corpus callosum were different according to antiepileptic drug responses in patients with newly diagnosed focal epilepsy, which might suggest that the volumes of the corpus callosum could be a new biomarker for predicting responses to antiepileptic drugs. K E Y W O R D Santiconvulsants, corpus callosum, epilepsy

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“…This does not rule out a focal onset though, as in true focal epilepsies we can also encounter that the focal disease only reveals itself because of a general lowering of the seizure generating threshold. As much as focal epilepsy can be considered a general brain network disorder (Englot et al, 2015), generalized epilepsies encounter some focal characteristics. Instead of the black-and-white division we might want to put epilepsy syndromes more in a gradual distribution between focal and generalized.…”

Section: See Article Pages Xxx-xxxmentioning

confidence: 99%