ABSTRACT
OBJECTIVE: Our goals were to study the propagation models in a situation of persistent temporal epileptic seizures with varying degrees of bitemporal excitability and to analyze which propagation models were found at times of high temporal excitability and which occurred with lower levels of excitability. METHODS: A patient with super-refractory status arising from the temporal lobes was studied daily using video-electroencephalography (VEEG), with a large number of electroclinical seizures recorded. The analysis focused on the method and type of seizure propagation and classified them either according to the propagation models described in the literature or as undetermined. RESULTS: Video-EEG monitoring was carried out daily for 310 days. A total of 990 electroclinical seizures were recorded; 135 seizures were recorded during the first week, and 523 were recorded in the first month. From the beginning, the interictal recording showed independent discharges over both temporal lobes. The seizures showed independent onset in both temporal lobes. During periods of the highest number of seizures, certain models of propagation begin to predominate through switch of lateralization, temporal asynchrony, early remote propagation, total contralateral propagation, seizures with nonlocalized onset, or models that are difficult to classify. Conversely, when the condition was brought relatively under control, we observed fewer propagation models with predominantly simple patterns: only hemispheric propagation or graduated sequential propagation with a few nonlateralized onset seizures. CONCLUSIONS: Upon analyzing the seizures, we found that the propagation models vary as the status evolved, with the change reflecting the degree of excitability in the mesial temporal-limbic network at a given time. In clinical practice, these changes in propagation models are more likely to be observed in temporal status that extends over time and with an onset of the seizures in both temporal lobes. SIGNIFICANCE: The analysis of the propagation models may provide information about the excitability of the mesial temporal-limbic network.
ABSTRACT
The purpose of this study was to describe the most common types of discharge propagation in mesial temporal epilepsy and to determine whether there are particular propagation characteristics that suggest a lesser degree of temporal excitability. This is a retrospective and analytical observation study with an open historical cohort of 22 patients with mesial temporal epilepsy among whom 75 complex partial seizures were recorded, with or without secondary generalization. Of the 75 seizures, 64 were of regionalized-lateralized onset, and their distance propagation sequence was analyzed. The onset, localization, and propagation sequence were identified. The patients were classified into three groups according to seizure propagation: group I (G I), with propagation to the ipsilateral hemisphere only; group II (G II), with gradual and sequential ipsilateral and contralateral propagation; and group III (G III), with total hemisphere toward the contralateral propagation. The G I and G II seizures were significantly associated with unitemporal interictal EEGs in comparison with the G III seizures (P = 0.00277). At the same time, the epilepsy was easier to control in G I and II, whereas all the G III patients were intractable (P = 0.0094). The G I and II had a greater tendency to be patients with pure mesial sclerosis than the G III. Most of the mesial temporal seizures observed showed propagation limited to the ipsilateral hemisphere at the onset of the discharge or a graduated sequential propagation. A lesser degree of unitemporal excitability was suggested in both situations, without significant alterations in the propagation times of the ipsilateral and contralateral epileptic discharges and relative preservation of the usual propagation pathways. The reverse situation was suggested among patients with total contralateral propagation seizures.
