Voxel-Based Morphometry Reveals Gray Matter Network Atrophy in Refractory Medial Temporal Lobe Epilepsy

Abstract

Background: Conventional volumetric studies have shown that brain structures functionally and anatomically related to the hippocampus are smaller in patients with drug-refractory medial temporal lobe epilepsy (MTLE). Objectives: To determine the extent of gray matter atrophy in the brains of patients with MTLE and to examine the pattern of atrophy. Design: We performed a voxel-based morphometric study of 43 consecutive patients with unilateral drugrefractory MTLE (21 patients with right-sided MTLE and 22 patients with left-sided MTLE) whose magnetic resonance images showed signs of unilateral hippocampal atrophy. The data from the patients with MTLE were compared with the data from 49 healthy control subjects to identify differences between groups in gray matter concentration (GMC).

An optimized voxel‐based morphometric study of gray matter changes in patients with left‐sided and right‐sided mesial temporal lobe epilepsy and hippocampal sclerosis (MTLE/HS)

“…In contrast to our results, some studies did not confirm rightward asymmetry and revealed a more widespread neuronal loss in patients with left‐sided MTLE (Bonilha et al., 2004, 2007; Bernhardt et al., 2008; Riederer et al., 2008) or an identical pattern of gray matter decrease in the two subgroups of patients (Bernasconi et al., 2004). These discrepancies among the studies (variations in GMV decreases) probably reflect variations in methodology, for example, the absence of customized templates (Bernasconi et al., 2004), the comparison of contrasts of correlations between patients and controls (Bonilha et al., 2007), the cortical thickness measurements (Bernhardt et al., 2008), or the t ‐test of adjusted local GMV in our study.…”

An optimized voxel‐based morphometric study of gray matter changes in patients with left‐sided and right‐sided mesial temporal lobe epilepsy and hippocampal sclerosis (MTLE/HS)

“…In contrast to our results, some studies did not confirm rightward asymmetry and revealed a more widespread neuronal loss in patients with left‐sided MTLE (Bonilha et al., 2004, 2007; Bernhardt et al., 2008; Riederer et al., 2008) or an identical pattern of gray matter decrease in the two subgroups of patients (Bernasconi et al., 2004). These discrepancies among the studies (variations in GMV decreases) probably reflect variations in methodology, for example, the absence of customized templates (Bernasconi et al., 2004), the comparison of contrasts of correlations between patients and controls (Bonilha et al., 2007), the cortical thickness measurements (Bernhardt et al., 2008), or the t ‐test of adjusted local GMV in our study.…”

Grey matter volume in healthy and epileptic beagles using voxel-based morphometry – a pilot study

“…The hippocampus of Beagles with IE had statistically significant reduced GMV that was even obvious, when all epileptic Beagles were calculated together. This finding is consistent with several human VBM studies about TLE [ 45 , 46 , 49 , 55 , 56 , 69 , 77 ]. Volumetric studies in veterinary medicine also showed hippocampal atrophy in epileptic dogs [ 24 , 44 ].…”

“…Our study also revealed a statistically significant loss of GMV in occipital gyrus in SE and epileptic Beagles. These findings are consistent with several human medicine studies of TLE patients [ 46 , 47 , 49 , 55 , 58 ].…”

Voxel‐based Optimized Morphometry (VBM) of Gray and White Matter in Temporal Lobe Epilepsy (TLE) with and without Mesial Temporal Sclerosis

“…However, contralateral subcortical, cerebellar, and neocortical structures also were affected. These findings are in good agreement with previous studies using optimized VBM in TLE‐MTS (14–17,22). These GM volume reductions were associated with WM volume reductions in the ipsilateral limbic system (parahippocampal gyrus); temporal, frontal, and parietal lobe; and splenium of the corpus callosum.…”

An optimized voxel‐based morphometric study of gray matter changes in patients with left‐sided and right‐sided mesial temporal lobe epilepsy and hippocampal sclerosis (MTLE/HS)

“…In contrast to our results, some studies did not confirm rightward asymmetry and revealed a more widespread neuronal loss in patients with left‐sided MTLE (Bonilha et al., 2004, 2007; Bernhardt et al., 2008; Riederer et al., 2008) or an identical pattern of gray matter decrease in the two subgroups of patients (Bernasconi et al., 2004). These discrepancies among the studies (variations in GMV decreases) probably reflect variations in methodology, for example, the absence of customized templates (Bernasconi et al., 2004), the comparison of contrasts of correlations between patients and controls (Bonilha et al., 2007), the cortical thickness measurements (Bernhardt et al., 2008), or the t ‐test of adjusted local GMV in our study.…”

Grey matter volume in healthy and epileptic beagles using voxel-based morphometry – a pilot study

“…The hippocampus of Beagles with IE had statistically significant reduced GMV that was even obvious, when all epileptic Beagles were calculated together. This finding is consistent with several human VBM studies about TLE [ 45 , 46 , 49 , 55 , 56 , 69 , 77 ]. Volumetric studies in veterinary medicine also showed hippocampal atrophy in epileptic dogs [ 24 , 44 ].…”

“…Our study also revealed a statistically significant loss of GMV in occipital gyrus in SE and epileptic Beagles. These findings are consistent with several human medicine studies of TLE patients [ 46 , 47 , 49 , 55 , 58 ].…”

Voxel‐based Optimized Morphometry (VBM) of Gray and White Matter in Temporal Lobe Epilepsy (TLE) with and without Mesial Temporal Sclerosis

“…However, contralateral subcortical, cerebellar, and neocortical structures also were affected. These findings are in good agreement with previous studies using optimized VBM in TLE‐MTS (14–17,22). These GM volume reductions were associated with WM volume reductions in the ipsilateral limbic system (parahippocampal gyrus); temporal, frontal, and parietal lobe; and splenium of the corpus callosum.…”

An optimized voxel‐based morphometric study of gray matter changes in patients with left‐sided and right‐sided mesial temporal lobe epilepsy and hippocampal sclerosis (MTLE/HS)

“…In contrast to our results, some studies did not confirm rightward asymmetry and revealed a more widespread neuronal loss in patients with left‐sided MTLE (Bonilha et al., 2004, 2007; Bernhardt et al., 2008; Riederer et al., 2008) or an identical pattern of gray matter decrease in the two subgroups of patients (Bernasconi et al., 2004). These discrepancies among the studies (variations in GMV decreases) probably reflect variations in methodology, for example, the absence of customized templates (Bernasconi et al., 2004), the comparison of contrasts of correlations between patients and controls (Bonilha et al., 2007), the cortical thickness measurements (Bernhardt et al., 2008), or the t ‐test of adjusted local GMV in our study.…”

Grey matter volume in healthy and epileptic beagles using voxel-based morphometry – a pilot study

“…The hippocampus of Beagles with IE had statistically significant reduced GMV that was even obvious, when all epileptic Beagles were calculated together. This finding is consistent with several human VBM studies about TLE [ 45 , 46 , 49 , 55 , 56 , 69 , 77 ]. Volumetric studies in veterinary medicine also showed hippocampal atrophy in epileptic dogs [ 24 , 44 ].…”

“…Our study also revealed a statistically significant loss of GMV in occipital gyrus in SE and epileptic Beagles. These findings are consistent with several human medicine studies of TLE patients [ 46 , 47 , 49 , 55 , 58 ].…”

Voxel‐based Optimized Morphometry (VBM) of Gray and White Matter in Temporal Lobe Epilepsy (TLE) with and without Mesial Temporal Sclerosis

“…However, contralateral subcortical, cerebellar, and neocortical structures also were affected. These findings are in good agreement with previous studies using optimized VBM in TLE‐MTS (14–17,22). These GM volume reductions were associated with WM volume reductions in the ipsilateral limbic system (parahippocampal gyrus); temporal, frontal, and parietal lobe; and splenium of the corpus callosum.…”