Seizure-Related Cortical Volume Alterations in Alzheimer's Disease: A Preliminary Study.

Background and Purpose: Alzheimer's disease (AD) leads to cognitive dysfunction and neuronal loss, both of which can be exacerbated by seizures. For the treatment and diagnosis of AD, it is imperative to identify the cortical characteristics of comorbidities of AD such as seizures. The present study investigated the alterations in cortical volumes in patients with comorbid AD and seizures.

Methods: In this retrospective study, magnetic resonance T1-weighted brain images were collected from six patients with early AD or amnestic mild cognitive impairment without seizures (AD-No Seizure, age: 66.17 ± 4.92 years) and six individuals with seizures (AD-Seizure, age: 80.33 ± 4.63 years). The gray matter volumes estimated from the T1 images were compared between the groups using nuisance variables (e.g., age). Subsequently, a correlation analysis was performed to investigate the relationship between cortical structure and global cognitive function.

Results: AD-Seizure group showed volumetric alterations compared with AD-No Seizure group. In the volumetrically altered regions, correlation analysis revealed that the AD-Seizure group showed a positive correlation between the mini-mental state examination (MMSE) score and cortical volume, with smaller volumes than the AD-No Seizure group in the right parahippocampal gyrus, left angular gyrus, and middle temporal gyrus. The AD-No Seizure group showed negative correlations with MMSE score in the volume of right inferior frontal gyrus and cerebellar culmen and a positive correlation with the volume of the left middle frontal gyrus.

Conclusions: Our findings revealed that smaller temporal region volumes are predictive of cognitive dysfunction in AD patients with seizures. Given that these temporal areas overlap with regions showing abnormal brain activities in AD patients with seizures, these results suggest synergistic effects of AD and seizures on cortical volume and cognitive function.