Absolute spike frequency and different comorbidities in temporal lobe epilepsy.

OBJECTIVE: The objective of this study was to examine if the absolute number of interictal epileptiform discharges (IED) is related to the presence of different comorbidities and refractivity in patients with temporal lobe epilepsy. METHODS: Analysis with scalp EEG of the IED of 30 patients with temporal epilepsy. The analysis was performed in three selected periods of the record during N2-N3 sleep. We analyzed the number of IED and the sum of the values obtained in the three selected segments to determine the absolute interictal spike frequency. RESULTS: The number of IED for patients varied from 11 to 450. The absolute interictal spike frequency showed a statistically significant relation with the presence of refractivity (p < 0.05), and neurological and/or psychiatric comorbidity (p < 0.05). Patients with an absolute interictal spike frequency ≤ 60 showed little refractoriness and no comorbidity. Patients with an absolute interictal spike frequency > 60 were mostly refractory and with neurological and/or psychiatric comorbidity. No significant relation was found of absolute interictal spike frequency with age at the onset of epilepsy, number of anticonvulsant drugs used, or base pathology (MRI). CONCLUSIONS: The absolute interictal spike frequency is capable of differentiating patients with temporal lobe epilepsy, identifying those with temporal lobe epilepsy according to the severity of the condition. Only those patients with non-frequent spikes (≤60 over the affected temporal lobe) have a low percentage of refractoriness with little or no presence of comorbidity.

Changing patterns of propagation in a super-refractory status of the temporal lobe. Over 900 seizures recorded over nearly one year.

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.

Graduated and sequential propagation in mesial temporal epilepsy: analysis with scalp ictal EEG.

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.

Two types of remote propagation in mesial temporal epilepsy: analysis with scalp ictal EEG.

The purpose of this study was to describe the propagation pattern of ictal discharges, particularly remote patterns from a localized onset in patients with mesial temporal epilepsy, and to determine whether this provides additional information to that obtained from prolonged presurgery scalp EEG monitoring. This is a retrospective and analytical study that included a historical open cohort of 18 patients with mesial temporal epilepsy, among whom 56 regionalized-lateralized onset seizures were recorded. These seizures were analyzed as to whether remote propagation occurred and as to their temporal characteristics. Thirty-eight regionalized-lateralized onset seizures did not show remote propagation, whereas 18 did. Two types of remote propagation were identified, one early and one late, depending on whether the remote propagation occurred before or after 10 seconds had elapsed from the onset of the electroencephalographic seizure. When the seizures were compared according to the type of propagation, those with early remote propagation showed a correlation, not statistically significant, with the intractability of the epilepsy (P = 0.0754), toward independent bitemporal interictal discharges (P = 0.1667), and from the MRI perspective, to occur with temporal lesions other than pure mesial sclerosis (P = 0.6329). Early remote propagation seizures were not associated with nonlateralized onset (P = 0.2682). The only patient in our study with switch of lateralization seizures experienced early remote propagation seizures. Patients with late remote propagation seizures and those without remote propagation showed no statistically significant differences with respect to these variables. Ictal recording with scalp EEG allows for differentiating between early and late remote propagation in patients with mesial temporal epilepsy and regionalized-lateralized onset seizures. Early remote propagation probably identifies a subgroup of these patients with greater uni- or bitemporal hyperexcitability.