How Red Are Red Flags in Lesional Childhood Temporal Lobe Epilepsy? An Electro-Clinico-Anatomical Correlation Analysis of Intracranial Video-EEG Data

Purpose: It is well known that in adults with lesional temporal lobe epilepsies (lTLE), a rapid seizure spread to the frontal lobe can cause frontal or other extratemporal symptoms. In contrast, in children with lTLE, these symptoms are considered as signs for an epileptogenic zone involving more than only the temporal lobe.

Methods: We retrospectively analyzed all patients (n = 10; 8.5–20 years) who received temporal lobe resections following invasive EEG-video-monitoring in our center who had shown (1) exclusively temporal abnormalities on high-resolution MRI and (2) extratemporal seizure semiologies.

Results: Four of the ten patients showed both extratemporal and temporal seizure onsets on invasive recordings; as expected, none became completely seizure-free after the (temporal) resection. In 6/10, however, invasive EEG monitoring showed exclusively temporal seizure onsets and confirmed ictal propagation to the frontal lobe prior to the onset of frontal seizure semiology. Four of the six patients became seizure free after the operation (follow-up: 5–56 m). In one patient who did not become seizure-free after the operation, histology confirms further to the MRI suspicion of focal cortical dysplasia (limbic) encephalitis. The second was incompletely resected to conserve Wernicke’s area.

Conclusion: As in adults, extratemporal semiology in children can indicate an extratemporal epileptogenic zone despite temporal MRI abnormalities. Six of the ten patients in our series did not become seizure free. In the subgroup of patients with exclusively temporal seizure onsets, postoperative seizure outcome was favorable: Four of the six patients became seizure free. This difference corroborates the usefulness of invasive EEG monitoring in children with this constellation, which can “unmask” extratemporal seizure symptoms as rapid propagations from the temporal lobe.