MRI volume loss of subcortical structures in unilateral temporal lobe epilepsy

Few studies have examined the relative degree of brain volume loss in both the hippocampi and subcortical structures in unilateral temporal lobe epilepsy (TLE) and their association with clinical seizure correlates. In this study, quantitative MRI volumes were measured in the hippocampus, thalamus, caudate, putamen, and corpus callosum in 48 patients with unilateral TLE (26 right, and 22 left) and compared with the volumes of 29 healthy controls. The ipsilateral hippocampus, corpus callosum, and bilateral thalami exhibited the greatest volume loss, reflected by large to moderate effect size differences compared with controls. Bilaterally, the putamen showed the next highest volume reduction. The contralateral hippocampus and bilateral caudate nuclei showed the least volume reduction, characterized by small effect sizes. Furthermore, clinical seizure characteristics (e.g., duration of epilepsy) exhibited different patterns of association with the volume reductions observed across these structures. Findings suggest that distinct neurodevelopmental features may play a role in the volume abnormality observed in these regions.