Lower myelin‐water content of the frontal lobe in childhood absence epilepsy

Abstract

Objective The frontal lobe in childhood absence epilepsy (CAE) might be affected due to the suggested involvement of the frontal lobe during absence seizures and reports on attentional deficits. Previously, subtle white matter abnormalities have been reported in CAE. However, the impact of one of the most characteristic components of the white matter, the myelin content, remains underdetermined. Therefore, this study investigated whether the myelin content in frontal areas is adversely affected in CAE compared to controls. Methods Seventeen children with childhood absence epilepsy (mean age ± standard deviation [SD], 9.2 ± 2.1 years) and 15 age‐ and sex‐matched controls (mean age ± SD, 9.8 ± 1.8 years) underwent neuropsychological assessment and a magnetic resonance imaging (MRI) examination. T2 relaxometry scans were used to distinguish myelin‐water from tissue water and to determine the myelin‐water fraction (MWF) in the frontal, temporal, parietal, occipital, and insular lobes. A linear regression model including age and sex as covariates was used to investigate group differences. Furthermore, the relationship of MWF with cognitive performance and epilepsy characteristics was determined. Results The frontal lobe revealed a significantly lower myelin‐water content in children with CAE compared to controls over the developmental age range of 6‐12 years (5.7 ± 1.0% vs 6.6 ± 1.1%, P = 0.02). This association was not found for any of the other four lobes (P > 0.10). No significant relation was found between myelin‐water content and cognitive performance or epilepsy characteristics. Significance The lower frontal myelin‐water content of children with CAE in comparison with healthy controls probably reflects an altered neurodevelopmental aspect in CAE, of which the underlying mechanisms still need to be unraveled.

Transcriptomic profiling of high- and low-spiking regions reveals novel epileptogenic mechanisms in focal cortical dysplasia type II patients

“…Conversely, previous studies have indicated that neurological disorders associated with abnormal myelin content are accompanied by a higher susceptibility to epileptic seizures [ 60 – 63 ]. Several studies have indicated that epilepsy is also associated with myelin abnormalities [ 64 – 69 ]. Oligodendrocytes also control potassium accumulation in white matter and seizure susceptibility [ 70 ].…”

Multifrequency Dynamics of Cortical Neuromagnetic Activity Underlying Seizure Termination in Absence Epilepsy

“…The involvement of the cortex during absence seizures in CAE has been reported in many studies ( Tenney et al, 2013 ; Miao et al, 2014a ; Tang et al, 2016 ; Jun et al, 2019 ). Moreover, cortical impairment has also been reported even in the interictal period ( Xiang et al, 2015b ; Qiu et al, 2016 ; Drenthen et al, 2019 ). Previous reports on source changes in the pre-ictal period have demonstrated that SWDs built up gradually rather than occurring suddenly and that the cortex played a leading role in the initiation of absence seizures ( Gupta et al, 2011 ; Jacobs-Brichford et al, 2014 ; Wu et al, 2017b ).…”

In vivo Characterization of MRI-based T1w/T2w Ratios and Covariance Network in Temporal Lobe Epilepsy

“…Previous studies using diffusion tensor imaging have observed widespread microstructural organizational changes, such as reduced fractional anisotropy (FA), which is possibly linked to myelination alterations [27]. Previous work has reported aberrant myelin content in children with epilepsy [28]. Moreover, a recent review also suggested a relationship between pathophysiology of epilepsy and myelin abnormalities [29].…”