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MRI and EEG as long-term seizure outcome predictors in familial mesial temporal lobe epilepsy
Marcia E Morita1, Clarissa Lin Yasuda, Luiz E Betting
1Neuroimaging Laboratory, UNICAMP (University of Campinas), Brazil.
Objective:
To evaluate the natural history and outcome predictors in familial mesial temporal lobe epilepsy (FMTLE).
Methods:
We conducted a longitudinal study of 103 individuals from 17 FMTLE families (mean follow-up: 7.6 years). We divided subjects into 3 groups: FMTLE (n = 53), unclassified seizure (n = 18), and asymptomatics (n = 32). We divided FMTLE patients into 3 subgroups: seizure-free (n = 19), infrequent (n = 17) seizures, and frequent (n = 17) seizures and further reclassified them into favorable and poor outcome. We defined hippocampal atrophy (HA) by visual MRI analysis and performed volumetry in those who had 2 MRIs.
Results:
FMTLE patients with infrequent seizures evolved to either frequent seizures (17.6%) or seizure freedom (23.5%). In the seizure-free group, most remained seizure-free and 21% developed infrequent seizures. All patients with frequent seizures remained in the same status or underwent surgery. Twelve percent of the asymptomatics and 22% of the unclassified-seizure group evolved to FMTLE with infrequent seizures. Predictive factors of poor outcome were presence of HA (p = 0.0192) and interictal epileptiform discharges (p = 0.0174). The relationship between initial precipitating incidents and clinical outcome was not significant although a tendency was observed (p = 0.055). Use of antiepileptic drugs and secondary generalized seizures during the patient's lifetime did not predict poor outcome. We observed progression of HA only in the group with frequent seizures.
Conclusion:
Most patients with FMTLE continued in the same clinical status. However, patients with frequent seizures had progression of HA and none improved except those who underwent surgery. Interictal epileptiform discharges and HA predicted poorer outcome in FMTLE, and there was a tendency in favor of initial precipitating incidents as outcome predictors.
Insights
Familial mesial temporal lobe epilepsy (FMTLE) often persists, with frequent seizures indicating poor prognosis. Hippocampal atrophy and epileptiform discharges predict worse outcomes in FMTLE patients.
Area of Science:
- Neurology
- Epilepsy Research
- Clinical Neuroscience
Background:
- Familial mesial temporal lobe epilepsy (FMTLE) is a distinct epilepsy syndrome.
- Understanding its natural history and predictors of outcome is crucial for patient management.
Purpose of the Study:
- To evaluate the natural history of familial mesial temporal lobe epilepsy (FMTLE).
- To identify predictors of outcome in individuals with FMTLE.
Main Methods:
- A longitudinal study of 103 individuals from 17 FMTLE families over a mean follow-up of 7.6 years.
- Classification into FMTLE, unclassified seizure, and asymptomatic groups, with FMTLE patients further categorized by seizure frequency and outcome.
- Assessment of hippocampal atrophy (HA) via MRI and volumetry.
Main Results:
- Most FMTLE patients maintained their seizure status; frequent seizures often persisted or led to surgery.
- Hippocampal atrophy (HA) and interictal epileptiform discharges were significant predictors of poor outcome (p=0.0192 and p=0.0174, respectively).
- Progression of HA was observed primarily in patients with frequent seizures.
Conclusions:
- Familial mesial temporal lobe epilepsy (FMTLE) typically follows a persistent clinical course.
- Hippocampal atrophy (HA) and interictal epileptiform discharges are key predictors of poorer outcomes in FMTLE.
- Surgical intervention was the main route to improvement for patients with frequent seizures.
