The relationship between white matter abnormalities and cognitive functions in new-onset juvenile myoclonic epilepsy

Ekmekçi, Burcu; Bulut, Hacı Taner; Gümüştaş, Funda; Yıldırım, Adem; Kuştepe, Ali

doi:10.1016/j.yebeh.2016.07.015

Cited by 22 publications

(23 citation statements)

References 30 publications

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“…Moreover, alterations of diffusion parameters in the temporal lobe WM is associated with delayed and immediate memory performances (Riley et al, 2010;Yogarajah et al, 2008). Preliminary data in patients with both idiopathic generalized and focal epilepsy show WM diffusion alterations already at disease onset (Hutchinson et al, 2010;Widjaja et al, 2013), which were shown to correlate with executive functions (Ekmekci et al, 2016). WM diffusion characteristics may thus provide valuable information to predict which patients are at higher risk of developing cognitive deficits, such that they can be prevented through more effective treatments.…”

Section: Relations To Clinical and Cognitive Outcomesmentioning

confidence: 99%

Histological and MRI markers of white matter damage in focal epilepsy

et al. 2018

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Growing evidence highlights the importance of white matter in the pathogenesis of focal epilepsy. Ex vivo and post-mortem studies show pathological changes in epileptic patients in white matter myelination, axonal integrity, and cellular composition. Diffusion-weighted MRI and its analytical extensions, particularly diffusion tensor imaging (DTI), have been the most widely used technique to image the white matter in vivo for the last two decades, and have shown microstructural alterations in multiple tracts both in the vicinity and at distance from the epileptogenic focus. These techniques have also shown promising ability to predict cognitive status and response to pharmacological or surgical treatments. More recently, the hypothesis that focal epilepsy may be more adequately described as a system-level disorder has motivated a shift towards the study of macroscale brain connectivity. This review will cover emerging findings contributing to our understanding of white matter alterations in focal epilepsy, studied by means of histological and ultrastructural analyses, diffusion MRI, and large-scale network analysis. Focus is put on temporal lobe epilepsy and focal cortical dysplasia. This topic was addressed in a special interest group on neuroimaging at the 70th annual meeting of the American Epilepsy Society, held in Houston December 2-6, 2016.

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Section: Relations To Clinical and Cognitive Outcomesmentioning

confidence: 99%

Histological and MRI markers of white matter damage in focal epilepsy

et al. 2018

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“…There are 10 studies published in English that evaluated WM integrity in JME using diverse analytic methods of DTI ( Table 4 ). 8 – 10 , 21 , 22 , 41 , 58 , 97 – 99 Using a whole-brain voxel-wise manner implemented in statistical parametric mapping (SPM; http://www.fil.ion.ucl.ac.uk/spm/ ), Deppe et al 8 first reported significant FA reductions in WM regions associated with the anterior thalamus and prefrontal cortex in a patient group, indicating that JME is associated with WM abnormalities of the thalamofrontal network. A subsequent study by the same group employed a region of interest approach and detected FA reductions in the thalamocortical and frontal WM tracts, corroborating their former findings.…”

Section: White Matter Changesmentioning

confidence: 99%

“… 10 Other DTI studies using either a region of interest or whole-brain voxel-wise approach replicated the findings of disrupted microstructural integrity (reduced FA and increased MD) of the WM tracts, particularly the corpus callosum and frontal WM tracts, emphasizing widespread WM abnormalities in the pathogenetic process that underlies JME. 22 , 58 , 98 , 99 …”

Section: White Matter Changesmentioning

confidence: 99%

Grey and White Matter Alterations in Juvenile Myoclonic Epilepsy: A Comprehensive Review

Kim¹

2017

J Epilepsy Res

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Juvenile myoclonic epilepsy (JME) has been classified as a syndrome of idiopathic generalized epilepsy and is characterized by a strong genetic basis, age-specific onset of seizures, specific types of seizures, generalized spike-wave discharges on electroencephalography, and a lack of focal abnormality on magnetic resonance imaging (MRI). Recently, a wide range of advanced neuroimaging techniques have been utilized to elucidate the neuroanatomical substrates and pathophysiological mechanisms underlying JME. Specifically, a number of quantitative MRI studies have reported focal or regional abnormalities of the subcortical and cortical grey matter, particularly the thalamus and frontal cortex, in JME patients. In addition, diffusion tensor imaging studies have pointed to disrupted microstructural integrity of the corpus callosum and multiple frontal white matter tracts as well as thalamofrontal dysconnectivity in JME patients. Converging evidence from neuroimaging studies strongly suggests that JME is a predominantly thalamofrontal network epilepsy, challenging the traditional concept of JME as a generalized epilepsy. There is also limited evidence indicating extrafrontal and extrathalamic involvement in JME. This systematic review outlines the main findings from currently available MRI studies focusing on grey and white matter alterations, and discusses their contributions to the etiology and pathophysiology of JME. The clinical utility, advantages, and drawbacks of each imaging modality are briefly described as well.

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“…The alterations in VDN-related inter-RSN dynamics may be associated with the attention dysfunction in patients with JME. The SCN, including thalamus, amygdala, hippocampus, caudate, and putamen, is highlighted in cognitive processes such as memory and information monitoring ( 54 ), and is reported with both structural and functional abnormalities in JME ( 4 , 55 – 57 ). Moreover, abnormal FC between the SCN and the DMN in the severe epilepsy of Lennox-Gastaut syndrome has been found in a recent study ( 58 ).…”

Section: Discussionmentioning

confidence: 99%

“…Myoclonic, generalized tonic-clonic and absences, as three common seizure types of IGE, may be evoked either by non-specific factors, such as sleep deprivation and stress, or by specific stimuli like photic stimuli, eye-closure, praxis, and language ( 2 ). Cognitive impairments in attention, memory and language dysfunctions have also been found in JME patients ( 3 , 4 ). Although substantial efforts have been made in the past decade, the fundamental pathogenesis of JME still remains largely unclear.…”

Section: Introductionmentioning

confidence: 99%

Changes in Dynamics Within and Between Resting-State Subnetworks in Juvenile Myoclonic Epilepsy Occur at Multiple Frequency Bands

et al. 2018

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Time-varying connectivity analyses have indicated idiopathic generalized epilepsy (IGE) could cause significant abnormalities in dynamic connective pattern within and between resting-state sub-networks (RSNs). However, previous studies mainly focused on the IGE-induced dynamic changes of functional connectivity (FC) in specific frequency band (0.01–0.08 Hz or 0.01–0.15 Hz), ignoring the changes across different frequency bands. Here, 24 patients with IGE characterized by juvenile myoclonic epilepsy (JME) and 24 matched healthy controls were studied using a data-driven frequency decomposition approach and a sliding window approach. The RSN dynamics, including intra-RSN dynamics and inter-RSN dynamics, was further calculated to investigate dynamic FC changes within and between RSNs in JME patients in each decomposed frequency band. Compared to healthy controls, JME patients not only showed frequency-dependent decrease in intra-RSN dynamics within multiple RSNs but also exhibited fluctuant alterations in inter-RSN dynamics among several RSNs over different frequency bands especially in the ventral/dorsal attention network and the subcortical network. Additionally, the disease severity had significantly negative correlations with both intra-RSN dynamics within the subcortical network and inter-RSN dynamics between the subcortical network and the default network at the lower frequency band (0.0095–0.0195 Hz). These results suggested that abnormal dynamic FC within and between RSNs in JME occurs at multiple frequency bands and the lower frequency band (0.0095–0.0195 Hz) was probably more sensitive to JME-caused dynamic FC abnormalities. The frequency subdivision and selection are potentially helpful for detecting particular changes of dynamic FC in JME.

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The relationship between white matter abnormalities and cognitive functions in new-onset juvenile myoclonic epilepsy

Cited by 22 publications

References 30 publications

Histological and MRI markers of white matter damage in focal epilepsy

Histological and MRI markers of white matter damage in focal epilepsy

Grey and White Matter Alterations in Juvenile Myoclonic Epilepsy: A Comprehensive Review

Changes in Dynamics Within and Between Resting-State Subnetworks in Juvenile Myoclonic Epilepsy Occur at Multiple Frequency Bands

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