Functional connectivity and language impairment in cryptogenic localization-related epilepsy

Vlooswijk, Mariëlle C.G.; Jansen, Jacobus F.A.; Majoie, Marian; Hofman, Paul; Krom, M.C.T.F.M. de; Aldenkamp, Albert P.; Backes, Walter H.

doi:10.1212/wnl.0b013e3181ebdd3e

Cited by 75 publications

(69 citation statements)

References 44 publications

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“…We are aware of one other study using a verbal fluency paradigm to study task‐based connectivity in TLE 10. These authors concluded that, “impaired language function may not necessarily be reflected by altered patterns or levels of cerebral activation, but may be characterized by improperly orchestrated activity in the language network” 10.…”

Section: Discussionmentioning

confidence: 99%

“…While structural “network disease” is unlikely to explain cognitive impairment in all cases,9 the underlying concept can be expanded to incorporate functional network disease as well. From this perspective some of the cognitive deficits in TLE, and indeed in epilepsy more generally, represent alterations in functional networks 9, 10, 11…”

Section: Introductionmentioning

confidence: 99%

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Cognitive impairment in epilepsy: the role of reduced network flexibility

Tailby

Kowalczyk

Jackson

2017

Ann Clin Transl Neurol

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ObjectiveThe dominant model of cognitive impairment in focal epilepsy has emphasised structural bases for cognitive deficits. Current theories of cognition in the healthy brain emphasise the importance of the reweighting of brain network interactions in support of task performance. Here, we explore the hypothesis that cognitive deficits in epilepsy arise through abnormalities of dynamic functional network interactions.MethodWe studied 19 healthy controls and 37 temporal lobe epilepsy (TLE) patients, using a behavioural measure of verbal fluency (the Controlled Oral Word Association Test) and an fMRI verbal fluency paradigm (Orthographic Lexical Retrieval).ResultsBehaviourally, verbal fluency was significantly impaired in TLE. Psychophysiological interaction analyses of the fMRI data, which capture state‐dependent changes in network connectivity, revealed reduced task‐dependent modulations of connectivity from left superior medial frontal cortex to left middle frontal gyrus in TLE patients. Individual differences in verbal fluency among TLE cases was correlated with task‐dependent changes in connectivity from left posterior cingulate to left superior medial frontal cortex, and from left superior medial frontal cortex to a range of right predominant brain areas.InterpretationThese data reveal that the typical pattern of task‐driven shifts in network connectivity is not observed in TLE. Our observations go beyond simple structure‐function associations and suggest that failure of network flexibility can be an important contributor to cognitive impairment in epilepsy.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cognitive impairment in epilepsy: the role of reduced network flexibility

Tailby

Kowalczyk

Jackson

2017

Ann Clin Transl Neurol

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“…Bettus et al (2009) found decreased basal functional connectivity in the left hemisphere in patients with LTLE, and in addition, they also observed increased basal functional connectivity within the right hemisphere in the same patient group. Cognitive impairments in patients with TLE have also been correlated with changes in functional connectivity (Vlooswijk et al, 2010;Waites et al, 2006;Zhang et al, 2009). Liao et al (2010) found both increases and decreases in resting-state functional connectivity in patients with TLE; two regions with significant decreases in connectivity displayed a negative correlation with the duration of epilepsy.…”

Section: Introductionmentioning

confidence: 99%

Functional Networks in Temporal-Lobe Epilepsy: A Voxel-Wise Study of Resting-State Functional Connectivity and Gray-Matter Concentration

et al. 2013

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Temporal-lobe epilepsy (TLE) involves seizures that typically originate in the hippocampus. There is evidence that seizures involve anatomically and functionally connected brain networks within and beyond the temporal lobe. Many studies have explored the effect of TLE on gray matter and resting-state functional connectivity in the brain. However, the relationship between structural and functional changes has not been fully explored. The goal of this study was to investigate the relationship between gray matter concentration (GMC) and functional connectivity in TLE at the voxel level. A voxel-wise linear regression analysis was performed between GMC maps and whole-brain resting-state functional connectivity maps to both the left thalamus (Lthal) and the left hippocampus (LH) in a group of 15 patients with left TLE. Twenty regions were found that exhibited GMC decreases linearly correlated with resting-state functional connectivity to either the LH or the Lthal in the patient group only. A subset of these regions had significantly reduced GMC, and one of these regions also had reduced functional connectivity to the LH in TLE compared to the controls. These results suggest a network of impairment in left TLE where more severe reductions in GMC accompany decreases (LH, Lthal, right midcingulate gyrus, left precuneus, and left postcentral gyrus) or increases (LH to right thalamus) in resting functional connectivity. However, direct relationships between these imaging parameters and disease characteristics in these regions have yet to be established.

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“…[1][2][3][4]6 Graph-theory analysis of resting-state fMRI data from patients with epilepsy also revealed decreased functional nodal topologic properties of the DMN that were positively correlated with disease duration. 8,[11][12][13][14] Regional homogeneity analysis of resting-state fMRI data was even used as a presurgical tool for seizure identification in patients with MR-negative focal epilepsy. 15 Thus, various models of data analysis have helped in understanding epilepsy further, and now there is increasing interest in using these models to reclassify epilepsy as a focal epileptogenic area 10,15 or as a network of seizure-generating areas.…”

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confidence: 99%

Seizure Frequency Can Alter Brain Connectivity: Evidence from Resting-State fMRI

Bharath

Sinha²,

Panda

et al. 2015

AJNR Am J Neuroradiol

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BACKGROUND AND PURPOSE:The frequency of seizures is an important factor that can alter functional brain connectivity. Analysis of this factor in patients with epilepsy is complex because of disease-and medication-induced confounders. Because patients with hot-water epilepsy generally are not on long-term drug therapy, we used seed-based connectivity analysis in these patients to assess connectivity changes associated with seizure frequency without confounding from antiepileptic drugs.

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Functional connectivity and language impairment in cryptogenic localization-related epilepsy

Abstract: Impaired performance on language assessment in epilepsy patients is associated with loss of functional connectivity in the cognitive language networks.

Cited by 75 publications

References 44 publications

Cognitive impairment in epilepsy: the role of reduced network flexibility

Cognitive impairment in epilepsy: the role of reduced network flexibility

Functional Networks in Temporal-Lobe Epilepsy: A Voxel-Wise Study of Resting-State Functional Connectivity and Gray-Matter Concentration

Seizure Frequency Can Alter Brain Connectivity: Evidence from Resting-State fMRI

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