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Published on: November 19, 2012
Hippocampal atrophy and T2-weighted signal changes in familial mesial temporal lobe epilepsy
E Kobayashi1, M D D'Agostino, I Lopes-Cendes
1Department of Neurology, Faculdade de Ciências Médicas, UNICAMP-Campinas, Brazil.
Objective:
To correlate the clinical phenotype with hippocampal volumes (HcVs) and signal changes in patients with familial mesial temporal lobe epilepsy (FMTLE).
Methods:
FMTLE was defined when at least two first-degree relatives in a family had a clinical-EEG diagnosis of MTLE. Hippocampal formation measurements were performed using 1- to 3-mm coronal T1-weighted MRIs. The presence of hyperintense T2 signal was evaluated by visual analysis. For statistical analyses, analysis of variance, chi(2) test, and regression analysis were used.
Results:
A total of 142 patients from 45 unrelated families were studied: 113 individuals with MTLE (80 with good seizure control) and 29 family members with other seizure types. There were 99 patients (69.7%) with hippocampal atrophy (HA). Sixty-seven of the 99 patients with HA also had a hyperintense T2 signal. Hyperintense T2 signal was associated with more severe HA (p = 0.04). Patients with refractory FMTLE had more frequent HA (p = 0.03) and hyperintense T2 signal (p = 0.004) and more severe atrophy (p < 0.0001). Duration of epilepsy correlated with HcV asymmetry index (r(2) = 0.12, p = 0.00008) and with the more atrophic hippocampi but not with contralateral hippocampi.
Conclusion:
In familial mesial temporal lobe epilepsy, seizure severity is variable in affected individuals. Hippocampal atrophy was present in 70% of these patients and 69% of these had an associated hyperintense T2 signal. Although hippocampal atrophy associated with abnormal T2 signal was more frequent and more severe in patients with poor seizure control, it was also frequent in affected individuals across families. These observations suggest that one or more genes resulting in familial mesial temporal lobe epilepsy predisposes both to the clinical features of mesial temporal lobe epilepsy and to the development of hippocampal sclerosis.
Insights
Familial mesial temporal lobe epilepsy (FMTLE) often involves hippocampal atrophy and abnormal T2 signals, particularly in patients with severe seizures. These findings suggest a genetic predisposition to both epilepsy and hippocampal sclerosis in FMTLE.
Area of Science:
- Neurology
- Genetics
- Radiology
Background:
- Familial mesial temporal lobe epilepsy (FMTLE) is a significant neurological disorder.
- Understanding the relationship between clinical presentation and brain imaging findings is crucial for diagnosis and management.
Purpose of the Study:
- To correlate clinical phenotypes with hippocampal volumes and signal changes in patients with familial mesial temporal lobe epilepsy (FMTLE).
Main Methods:
- Defined FMTLE based on clinical-EEG diagnosis in at least two first-degree relatives.
- Measured hippocampal formation volumes using MRI and assessed T2 signal hyperintensity visually.
- Employed ANOVA, chi-squared test, and regression analysis for statistical evaluation.
Main Results:
- Studied 142 patients from 45 families; 113 had mesial temporal lobe epilepsy (MTLE).
- Hippocampal atrophy (HA) was present in 69.7% of patients, with 67% of those showing hyperintense T2 signal.
- Refractory FMTLE correlated with more frequent and severe HA and abnormal T2 signals.
Conclusions:
- Hippocampal atrophy and abnormal T2 signals are common in FMTLE, suggesting a genetic link to hippocampal sclerosis.
- Seizure severity in FMTLE is variable, but imaging abnormalities are frequent across affected family members.
- These findings indicate that genetic factors in FMTLE predispose individuals to both epilepsy and hippocampal sclerosis.
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