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Published on: August 5, 2014
Longitudinal MRI volumetric evaluation in patients with familial mesial temporal lobe epilepsy
Livia Conz1, Marcia Elisabete Morita, Ana Carolina Coan
1Department of Neurology, University of Campinas, Campinas São Paulo, Brazil.
Introduction:
Studies have shown progressive cerebral damage in patients with refractory mesial temporal lobe epilepsy (MTLE). However, this has not been demonstrated in benign forms of MTLE such as familial mesial temporal lobe epilepsy (FMTLE).
Purpose:
To evaluate progression of hippocampal atrophy (HA) in patients with sporadic mesial temporal lobe epilepsy (SMTLE) and FMTLE by longitudinal Magnetic resonance images (MRIs) acquired with at least 7 months of interval.
Method:
We included 35 patients with FMTLE (25 classified as benign and 10 refractory) and 33 with SMTLE (4 benign and 29 refractory). All MRIs were analyzed by an investigator blind for clinical data. Hippocampal analyses were performed manually in coronal 3 mm thick T1 inversion recovery, using the software Scion Image(®). Volumes were compared to those from a control group, and HA was determined for volumes below two standard deviations from the mean of controls.
Results:
The mean interval between the first (MRI1) and second MRI (MRI2) was 90 months for FMTLE and 45 months for SMTLE group. FMTLE group: volumetry demonstrated HA in 20 patients in MRI1 and in 23 patients in MRI2. There was significant progression of HA in FMTLE patients between MRIs in both benign and refractory FMTLE patients (benign FMTLE: right hippocampus, p = 0.001 and left hippocampus, p < 0.001; refractory FMTLE: right hippocampus, p = 0.022 and left hippocampus, p < 0.010). SMTLE group: volumetry demonstrated HA in 27 patients in MRI1 and in 29 patients in MRI2. In the group analysis, there was a significant reduction of the right (p < 0.0001) and left (p < 0.0001) hippocampal volumes during the follow-up period. Although the mean time between the MRIs in the FMTLE group was twice the time of the SMTLE group, the progression of volume loss was similar in both groups, indicating a slower progression in the FMTLE patients.
Conclusion:
FMTLE patients have progressive hippocampal volume reduction independently of seizure frequency although the progression of HA seems to be slower than in SMTLE.
Insights
Familial mesial temporal lobe epilepsy (FMTLE) patients show progressive hippocampal atrophy, even in benign forms. This brain damage occurs independently of seizure frequency, though at a slower rate than in sporadic MTLE.
Area of Science:
- Neurology
- Neuroimaging
- Epilepsy Research
Background:
- Progressive cerebral damage is documented in refractory mesial temporal lobe epilepsy (MTLE).
- The progression of brain damage in benign forms, such as familial MTLE (FMTLE), remains less understood.
- This study investigates hippocampal atrophy progression in both familial and sporadic MTLE.
Purpose of the Study:
- To longitudinally evaluate hippocampal atrophy (HA) progression in patients with sporadic mesial temporal lobe epilepsy (SMTLE) and familial MTLE (FMTLE).
- To compare the rate of HA progression between FMTLE and SMTLE using serial Magnetic Resonance Imaging (MRI).
Main Methods:
- 35 FMTLE patients (25 benign, 10 refractory) and 33 SMTLE patients (4 benign, 29 refractory) underwent serial MRI scans.
- Manual hippocampal volumetry was performed on T1 inversion recovery MRI scans by an investigator blinded to clinical data.
- Hippocampal volumes were compared to controls, with HA defined as volumes below two standard deviations from the mean.
Main Results:
- Significant progression of HA was observed in both benign and refractory FMTLE patients over a mean follow-up of 90 months.
- SMTLE patients also showed significant bilateral hippocampal volume reduction over a mean follow-up of 45 months.
- Despite a longer interval between scans, FMTLE patients exhibited a similar rate of volume loss compared to SMTLE patients, suggesting slower progression in FMTLE.
Conclusions:
- Familial MTLE patients experience progressive hippocampal volume reduction, irrespective of seizure frequency.
- The rate of hippocampal atrophy in FMTLE appears to be slower compared to SMTLE.
- These findings highlight progressive neurodegeneration in both familial and sporadic forms of MTLE.
