Authors :
Presenting Author: Hea Ree Park, MD, PhD – Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
Gilsoon Park, PhD – USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of USC, University of Southern California, Los Angeles, California, 90033, USA
Suyeon Seo, MD – Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
Eun Yeon Joo, MD, PhD – Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
Hosung Kim, PhD – USC Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of USC, University of Southern California, Los Angeles, California, 90033, USA
Rationale:
Mesial temporal lobe epilepsy (MTLE) is linked to progressive brain structural changes and cognitive decline, suggesting accelerated brain aging in chronic stages. The brain age index (BAI), determined by subtracting chronological age from brain age predicted from neurobiological data, has emerged as a potential biomarker for pathologic brain aging in various conditions. This study investigated regional BAI in patients with MTLE using structural MRI data and explores its association with surgical outcomes.
Methods:
We retrospectively analyzed T1-weighted MRI data from 217 MTLE patients (age: 34.6±10.5 years) who underwent surgery after MRI scanning and 6,243 healthy controls (age: 37.0±20.6 years). The cerebral cortex was defined into 9 functional regions (sensorimotor, frontoparietal, dorsal attention, ventral attention with language, default mode, salience, auditory, visual, and limbic), based on automated anatomical labeling. For each ROI, we calculated cortical thickness and the ratio of gray matter to white matter intensity as cortical morphometric measurements. The connectivity information obtained from 18 ROIs and two cortical features were used as the input of our model. Separate graph convolutional networks models were trained for each of the 9 regions in both hemispheres, yielding 18 brain ages per individual. BAI was calculated by subtracting chronological age from predicted brain age. We compared the BAIs between MTLE patients and healthy controls, and between ipsilesional and contralesional BAIs within the MTLE group. Association between BAI and disease duration and surgical outcome were evaluated using linear regression.
Results:
MTLE patients exhibited increased BAI across most functional regions on both ipsilateral and contralateral sides of epileptogenic zone (Figure 1). Significantly higher BAI values were observed on the ipsilateral side of the epileptogenic zone, particularly in the dorsal attention and ventral attention/language networks (Table 1). With longer disease duration, BAI increased in the contralateral visual network. While no significant association was found between regional BAI and short-term (two-year) outcomes, higher BAI in the ipsilateral ventral attention/language network, and in the contralateral auditory and frontoparietal networks were significantly associated with poorer long-term (5-year) outcomes.
Conclusions:
This study demonstrates widespread accelerated brain aging in patients with MTLE, particularly in dorsal attention and ventral attention/language areas. We found significant association between long-term surgical outcome and increased BAI in some regions, suggesting potential of BAI as a prognostic biomarker for surgical treatment in MTLE.
Funding:
This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number : RS-2024-00440131)