Thalamic volume reduction in drug-naive patients with new-onset genetic generalized epilepsy

Abstract

<jats:title>Summary</jats:title><jats:sec><jats:title>Objective</jats:title><jats:p>Patients with genetic generalized epilepsy (<jats:styled-content style="fixed-case">GGE</jats:styled-content>) have subtle morphologic abnormalities of the brain revealed with <jats:styled-content style="fixed-case">magnetic resonance imaging (MRI)</jats:styled-content>, particularly in the thalamus. However, it is unclear whether morphologic abnormalities of the brain in <jats:styled-content style="fixed-case">GGE</jats:styled-content> are a consequence of repeated seizures over the duration of the disease, or are a consequence of treatment with antiepileptic drugs (<jats:styled-content style="fixed-case">AED</jats:styled-content>s), or are independent of these factors. Therefore, we measured brain morphometry in a cohort of AED‐naive patients with <jats:styled-content style="fixed-case">GGE</jats:styled-content> at disease onset. We hypothesize that drug‐naive patients at disease onset have gray matter changes compared to age‐matched healthy controls.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>We performed quantitative measures of gray matter volume in the thalamus, putamen, caudate, pallidum, hippocampus, precuneus, prefrontal cortex, precentral cortex, and cingulate in 29 AED‐naive patients with new‐onset <jats:styled-content style="fixed-case">GGE</jats:styled-content> and compared them to 32 age‐matched healthy controls. We subsequently compared the shape of any brain structures found to differ in gray matter volume between the groups.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>The thalamus was the only structure to show reduced gray matter volume in AED‐naive patients with new‐onset <jats:styled-content style="fixed-case">GGE</jats:styled-content> compared to healthy controls. Shape analysis revealed that the thalamus showed deflation, which was not uniformly distributed, but particularly affected a circumferential strip involving anterior, superior, posterior, and inferior regions with sparing of medial and lateral regions.</jats:p></jats:sec><jats:sec><jats:title>Significance</jats:title><jats:p>Structural abnormalities in the thalamus are present at the initial onset of <jats:styled-content style="fixed-case">GGE</jats:styled-content> in <jats:styled-content style="fixed-case">AED</jats:styled-content>‐naive patients, suggesting that thalamic structural abnormality is an intrinsic feature of <jats:styled-content style="fixed-case">GGE</jats:styled-content> and not a consequence of <jats:styled-content style="fixed-case">AED</jats:styled-content>s or disease duration.</jats:p></jats:sec>