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The following is a summary of “Brain Hypertrophy in Patients With Mesial Temporal Lobe Epilepsy With Hippocampal Sclerosis and Its Clinical Correlates,” published in the December 2024 issue of Neurology by Zubal et al.
Individuals with mesial temporal lobe epilepsy (mTLE) and hippocampal sclerosis typically experience brain atrophy, but the connection to brain hypertrophy remains unclear.
Researchers conducted a retrospective study to examine brain hypertrophy and the clinical correlates in individuals with mTLE.
They analyzed brain magnetic resonance imaging (MRI) data from 135 individuals with mTLE and hippocampal sclerosis (77 left-sided, 58 right-sided; 82 women; mean age 37 ± 11 years) and 47 healthy volunteers (29 women; mean age 36 ± 11 years) using voxel-based morphometry (VBM), surface-based morphometry (SBM), volumetry, and shape analysis. The findings were validated in a second cohort (18 individuals with mTLE, 18 healthy volunteers), and functional MRI (fMRI) was used to evaluate memory encoding.
The results showed increased contralateral amygdala volume in individuals with left-sided mTLE (1.74 ± 0.16 mL, P<.001) and right-sided mTLE (1.79 ± 0.18 mL, P=.002) compared to healthy volunteers (1.64 ± 0.11 mL and 1.70 ± 0.11 mL, respectively). Validation cohort findings supported the results (1.91 ± 0.20 mL vs. 1.75 ± 0.13 mL, P=.009). In individuals with left-sided mTLE, hypertrophy correlated with poorer verbal memory. In those with right-sided mTLE, that was linked to more frequent focal-to-bilateral tonic-clonic seizures. Contralateral amygdala hypertrophy was also associated with increased right parietal memory encoding activation in 44 individuals with mTLE and 26 healthy volunteers who received fMRI.
They concluded that contralateral amygdala hypertrophy in individuals with mTLE and hippocampal sclerosis may reflect compensatory plasticity, or the effects of seizure spread.
Source: neurology.org/doi/10.1212/WNL.0000000000210182
