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Updated: Aug 6, 2026
Anteromesial Temporal Lobectomy for Medically Intractable Temporal Lobe Epilepsy: An Operative Study
Published on: August 15, 2025
Gray matter atrophy associated with duration of temporal lobe epilepsy
Leonardo Bonilha1, Chris Rorden, Simone Appenzeller
1Department of Neuropsychiatry, University of South Carolina, SC 29425, USA.
Abstract:
Hippocampal sclerosis is the most common abnormality associated with medial temporal lobe epilepsy (MTLE). Converging evidence supports that hippocampal sclerosis progresses with time. However, it is unclear whether extrahippocampal atrophy in patients with MTLE, similarly to hippocampal sclerosis, is an unremitting progressive process. In this article, we investigate the relationship between duration of epilepsy and gray matter concentration reduction in patients with MTLE within and outside the hippocampus. We employed a voxel-based morphometry study of MRI of the entire brain of 36 patients with drug refractory MTLE and 49 neurologically healthy age-matched controls. We performed a voxel-based parametric and nonparametric investigation of the association between gray matter concentration, age and duration of epilepsy. We complemented the investigation by extracting the gray matter concentration of regions of interest (ROIs) within the limbic system, and we investigated the association between the gray matter concentration on the ROIs and duration of epilepsy. Patients with MTLE exhibited gray matter concentration reduction that is negatively correlated with the duration of epilepsy within the ipsilateral hippocampus, temporal lobes as well as extratemporal limbic structures that are closely connected with the hippocampus. In conclusion, longer duration of refractory epilepsy was associated with a more intense hippocampal and extrahippocampal atrophy in patients with MTLE. The mechanism of progressive neuronal damage in MTLE may be related to active seizure activity within a limbic network, and early seizure control may prevent further brain atrophy in patients with refractory MTLE.
Insights
Longer epilepsy duration in medial temporal lobe epilepsy (MTLE) correlates with increased brain atrophy, both inside and outside the hippocampus. Early seizure control may prevent further progressive neuronal damage in these patients.
Area of Science:
- Neuroscience
- Radiology
- Epilepsy Research
Background:
- Hippocampal sclerosis is a common finding in medial temporal lobe epilepsy (MTLE).
- Evidence suggests hippocampal sclerosis progresses over time.
- The progressive nature of extrahippocampal atrophy in MTLE remains unclear.
Purpose of the Study:
- To investigate the relationship between epilepsy duration and gray matter reduction in MTLE patients.
- To determine if atrophy extends beyond the hippocampus in MTLE.
- To explore the association between gray matter concentration and epilepsy duration within and outside the hippocampus.
Main Methods:
- Voxel-based morphometry (VBM) study using MRI scans of 36 drug-refractory MTLE patients and 49 healthy controls.
- Parametric and nonparametric analyses to assess gray matter concentration, age, and epilepsy duration.
- Region of interest (ROI) analysis within the limbic system.
Main Results:
- Gray matter concentration reduction negatively correlated with epilepsy duration in MTLE patients.
- Atrophy observed within the ipsilateral hippocampus, temporal lobes, and connected extratemporal limbic structures.
- Longer epilepsy duration was associated with more severe hippocampal and extrahippocampal atrophy.
Conclusions:
- Prolonged duration of refractory MTLE is linked to increased hippocampal and extrahippocampal atrophy.
- Progressive neuronal damage in MTLE may involve seizure activity within the limbic network.
- Early seizure control could potentially mitigate further brain atrophy in refractory MTLE.
