Secondary Generalization Prolonges Seizure Duration in Temporal but not in Frontal Lobe Epilepsies

Purpose: To evaluate the duration of seizures arising from the frontal and temporal lobes in order to better understand spread and inhibitory mechanisms involved.

Methods: We investigated the seizure duration as measured by ictal non-invasive EEG in 233 seizures arising from the temporal and frontal lobes in 41 patients with temporal and frontal lobe epilepsies.

Results: Of the 130 seizures arising from the temporal lobes 13.8%generalized secondarily, compared to 24.3% secondary generalization in 103 seizures of FLE. In TLE patients, the average duration was significantly longer in secondarily generalized seizures (95s) as in non-generalized seizures of TLE patients (62s; p=0.002). In FLE patients, the average duration of non-generalized seizures (66s) did not differ from seizures that generalized secondarily (68s). Secondary generalization of ictal epileptic activity prolonged seizure duration in TLE but not in FLE.

Conclusion: We conclude that in FLE, inhibitory mechanisms are activated earlier than in TLE and, therefore, secondary generalization does not prolong seizure duration in FLE.