The role of the anterior insular cortex in ictal vomiting: a stereotactic electroencephalography study

Ictal vomiting is a rare manifestation most often associated with right temporal lobe epilepsy. The implication of the anterior insula in the occurrence of this symptom has been suggested based on the role of this region in swallowing and on the observation that electrical insular stimulation can elicit nausea and vomiting. We report the first case, to our knowledge, of a patient presenting with ictal vomiting who underwent bilateral intracranial exploration including insular depth electrodes. The seizure onset zone was localized in the left temporomesial structures, but the occurrence of ictal vomiting correlated in time with a discharge affecting exclusively the anterior part of both insular lobes. It is concluded that the occurrence of ictal vomiting reflects a propagation of the discharge to the insular cortex. Observation of this symptom at the very onset of the seizures in a patient with temporal lobe epilepsy is highly suggestive of an insular seizure onset zone.     

Ictal vomiting in association with left temporal lobe seizures in a left hemisphere language-dominant patient

Ictal vomiting is considered a localizing sign indicating nondominant lateralization in patients with partial seizures of temporal lobe origin. We report a case of ictal vomiting associated with left temporal seizure activity in a left hemisphere language-dominant patient with a left mesial temporal glioma. Bilateral mesial temporal depth electrodes helped verify seizure lateralization. Surgery consisting of tumor resection and a left anterior temporal lobectomy and amygdalohippocampectomy resulted in freedom from seizures and episodes of vomiting. This case indicates that ictal vomiting can occur as a manifestation of left temporal onset seizures in left hemisphere-dominant patients.     

Surgical treatment of hypermotor seizures originating from the temporal lobe

PurposeTo describe the characteristics of electroclinical manifestations in patients with hypermotor seizures (HMSs) originating from the temporal lobe.MethodsWe retrospectively reviewed the data of patients who underwent surgical treatments for seizure to identify patients with HMSs of temporal origin. We systematically reviewed patient seizure histories, imaging reports, video-EEG monitoring data, operative records and pathological findings.ResultsEight of the 9 patients reported auras. The ictal behavior included marked agitation in 5 patients and mild agitation in 4 patients. All of the 9 patients exhibited stiffness or dystonia of the upper limb or contralateral limbs during ictus. Seven of the 9 patients completed intracranial recording and at least 3 seizures were recorded for each patient. The intracranial recordings showed ictal activity originating from mesial temporal lobe in 6 patients and the lateral temporal lobe in 1 patient. The time interval of ictal propagation from the temporal to frontal lobe was 15.0 ± 8.3 s. While the time interval from EEG origination to the beginning of hypermotor behavior was 21.0 ± 8.1 s. Brain MRIs revealed hippocampal sclerosis in 3, neoplastic lesion in 1, and normal images in the remaining 5 patients. Patients were followed for 1–5 years after the anterior temporal lobectomy; 7 patients remained seizure-free throughout follow-up.ConclusionSome HMSs can originate from the temporal lobe. In carefully selected patients, surgical resection may lead to good outcomes.     

Low resolution electromagnetic tomography analysis of ictal EEG patterns in mesial temporal lobe epilepsy with hippocampal sclerosis

ObjectiveTo investigate the difference in the spatial distribution of scalp initial ictal discharge (IID) patterns in mesial temporal lobe epilepsy with hippocampal sclerosis (HS–MTLE).MethodsScalp ictal EEG data in 22 seizure-free patients after temporal lobectomy with amygdalo-hippocampectomy were classified as follows: a regular 5–9 Hz rhythm with a restricted temporal/subtemporal distribution (type 1, 11 patients), or an irregular 2–5 Hz rhythm with a widespread fronto-temporal distribution (type 2, 11 patients). EEG data were fragmented into segments of 1.28 s, both at ictal onset and at baseline. The LORETA solution of three frequency bands was compared between ictal and baseline using statistical non-parametric mapping (p < 0.01).ResultsThe LORETA solution of 5–9 Hz in type 2 had wider cortical activity in the ipsilateral fronto-temporal area, compared to type 1 with activation of the ipsilateral focal mesial and lateral temporal regions. The LORETA solution of 10–13 Hz in both types showed increased activity in the fronto-temporal area, which was wider in type 2 than type 1. Increased cortical activity of <5 Hz was not observed in type 1, whereas increased cortical activity was observed in the bilateral anterior frontal area in type 2.ConclusionsThe cortical source distribution in HS–MTLE may depend on scalp IID frequency. The neural generators of 5–13 Hz may be important for the formation of the ictal onset zone in both ictal patterns.SignificanceSpatial distributions in HS–MTLE patients differ with scalp IID frequency.     

The role of the insular cortex in temporal lobe epilepsy

The role of the insular cortex in the genesis of temporal lobe epileptic (TLE) seizures has been investigated in 21 patients with drug-refractory TLE using chronic depth stereotactic recordings of the insular cortex activity and video recordings of ictal symptoms during 81 spontaneous electroclinical seizures. All of the recorded seizures were found to invade the insula, most often after a relay in the ipsilateral hippocampus (19/21 patients). However, 2 patients had seizures that originated in the insular cortex itself. Ictal symptoms associated with the insular discharges were similar to those usually attributed to mesial temporal lobe seizures, so that scalp video-electroencephalographic monitoring does not permit making any difference between ictal symptoms of temporo-mesial and insular discharges. A favorable outcome was obtained after a temporal cortectomy sparing the insular cortex in 15 of 17 operated patients. Seizures propagating to the insular cortex were found to be fully controlled by surgery, whereas those originating in the insular cortex persisted after temporal cortectomy. The fact that seizures originating in the insular cortex are not influenced by temporal lobectomy is likely to explain some of the failures of this surgical procedure in TLE.     

Propagation of human complex-partial seizures: a correlation analysis.

Inter- and intrahemispheric propagation of ictal discharges was analysed in 7 epileptic patients having chronic intracranial electrodes. Five had temporal foci and two had frontal mesial foci. Correlation analysis of seizure discharge was used to detect the emergence of linear relationships between different structures both intra- and interhemispherically. This analysis included mesial and lateral temporal sites, cingulate gyri, anterior ventral and dorsomedial thalamic nuclei during the discharges of 13 ictal episodes. Correlation between temporal mesial structures was found to be low throughout seizure onset. Propagation of paroxysmal activity through the anterior ventral thalamic nuclei and cingulate gyri was observed in all cases with temporal or frontal mesial focus. Propagation of the discharge from the temporal lateral cortex to the contralateral homologue area was observed with a short delay during 4 complex-partial seizures originating in the temporal lobe. These results show that, even though the commissural pathways may have a role in propagation, it is a relatively unimportant one and they suggest that ictal activity during mesial temporal seizures may spread preferentially through the thalamic nuclei and cortical structures.     

Differences between mesial and neocortical magnetic-resonance-imaging-negative temporal lobe epilepsy

ObjectiveThe aim of this study was to assess clinical and electrophysiological differences within a group of patients with magnetic-resonance-imaging-negative temporal lobe epilepsy (MRI-negative TLE) according to seizure onset zone (SOZ) localization in invasive EEG (IEEG).MethodsAccording to SOZ localization in IEEG, 20 patients with MRI-negative TLE were divided into either having mesial SOZ–mesial MRI-negative TLE or neocortical SOZ–neocortical MRI-negative TLE. We evaluated for differences between these groups in demographic data, localization of interictal epileptiform discharges (IEDs), and the ictal onset pattern in semiinvasive EEG and in ictal semiology.ResultsThirteen of the 20 patients (65%) had mesial MRI-negative TLE and 7 of the 20 patients (35%) had neocortical MRI-negative TLE. The differences between mesial MRI-negative TLE and neocortical MRI-negative TLE were identified in the distribution of IEDs and in the ictal onset pattern in semiinvasive EEG. The patients with neocortical MRI-negative TLE tended to have more IEDs localized outside the anterotemporal region (p = 0.031) and more seizures without clear lateralization of ictal activity (p = 0.044). No other differences regarding demographic data, seizure semiology, surgical outcome, or histopathological findings were found.ConclusionsAccording to the localization of the SOZ, MRI-negative TLE had two subgroups: mesial MRI-negative TLE and neocortical MRI-negative TLE. The groups could be partially distinguished by an analysis of their noninvasive data (distribution of IEDs and lateralization of ictal activity). This differentiation might have an impact on the surgical approach.     

24-hour rhythmicity of seizures in refractory focal epilepsy

The occurrence of seizures in specific types of epilepsies can follow a 24-hour nonuniform or nonrandom pattern. We described the 24-hour pattern of clinical seizures in patients with focal refractory epilepsy who underwent video-electroencephalography monitoring. Only patients who were candidates for epilepsy surgery with an unequivocal seizure focus were included in the study. A total of 544 seizures from 123 consecutive patients were analyzed. Specific time of seizures were distributed along 3- or 4-hour time blocks or bins throughout the 24-hour period. The mean age of the subjects was 37.7 years, with standard deviation of 11.5 years, median of 37. The majority were females (70/56%). The majority of patients had a seizure focus located in the mesial temporal lobe (102/83%) and in the neocortical temporal lobe (13/11%). The remaining patients had a seizure focus located in the extratemporal lobe (8/6%). The most common etiology was mesial temporal sclerosis (86/69.9%). Nonuniform seizure distribution was observed in seizures arising from the temporal lobe (mesial temporal lobe and neocortical temporal lobe), with two peaks found in both 3- and 4-hour bins: 10:00–13:00/16:00–19:00 and 08:00–12:00/16:00–20:00 respectively (p = 0.004). No specific 24-hour pattern was identified in seizures from extratemporal location. The 24-hour rhythmicity of seizure distribution is recognized in certain types of epilepsy, but studies on the topic are scarce. Their replication and validation is therefore needed. Our study confirms the bimodal pattern of temporal lobe epilepsy independently of the nature of the lesion. However, peak times differ between different studies, suggesting that the ambient, rhythmic exogenous factors or environmental/social zeitgebers, may modulate the 24-hour rhythmicity of seizures. Characterization of these 24-hour patterns of seizure occurrence can influence diagnosis and treatment in selected types of epilepsy, such as the case of temporal lobe epilepsy, the most common drug-resistant epilepsy.     

Ictal Single Photon Emission Computed Tomography in Occipital Lobe Seizures

Summary: Purpose: Ictal single photon emission computed tomography (SPECT) has been evaluated as an adjunctive localizing technique in temporal lobe epilepsies and, to a lesser degree, in some extratemporal epilepsies. The purpose of this study was to determine whether occipital lobe seizures are associated with distinctive ictal cerebral blood perfusion (rCP) patterns.
Methods : SPECT was used with the tracer ^99mTc HMPAO to image ictal rCP in 6 patients in whom clinical, EEG, and imaging data indicated occipital lobe seizures.
Results : Two patterns of rCP were seen. Four patients had hyperperfusion that was restricted to the occipital lobe, and two patients had hyperperfusion of the occipital lobe and the ipsilateral mesial temporal lobe, with hypoperfusion of the lateral temporal lobe. The latter 2 patients had clinical and surface EEG evidence of temporal lobe involvement in the seizure discharge.
Conclusions : Ictal rCP patterns in occipital lobe seizures are distinct from those in temporal lobe seizures and may vary according to whether or not ipsilateral temporal lobe structures are involved in the ictal discharge.     

Temporal lobe surgery in medically refractory epilepsy: A comparison between populations based on MRI findings

IntroductionHigh resolution MRI findings suggestive of mesial temporal sclerosis (MRI-MTS) correlate with good outcome after surgery. However, a large group of patients present with normal brain MRI (N-MRI) and temporal lobe epilepsy (TLE). We aim to compare pre-operative ictal EEG patterns in predicting surgical outcomes in the population with MRI-MTS vs. N-MRI after selective anterior-mesial temporal lobe (AMTL) resection.Methods241 patients with unilateral anterior ictal EEG findings underwent selective AMTL resection. 143 MRI-MTS and 98 N-MRI patients were identified. Outcome was based on the modified Engel classification, ictal EEG pattern at seizure onset, demographics and MRI findings.ResultsSeizure-free outcome was seen in the MRI-MTS in 79% of patients, compared to 59.1% (p < .005) of the N-MRI group. No significant difference was identified in ictal EEG patterns at presentation between groups. Class I outcome was achieved in 78.9% of patients that had theta rhythm and MRI-MTS compared to 57.9% of patients that had theta rhythm and N-MRI (p < 0.05).Discussion and conclusionSurgical treatment for mesial TLE is effective. Positive MRI suggestive of mesial temporal sclerosis (MTS) predicts better seizure control after surgery. Theta rhythm is the most common ictal pattern and seems to carry the best prognosis for TLE. However, a well-selected group of patients with N-MRI will benefit from surgical intervention, and similar outcome to MRI-MTS patients can be achieved if delta ictal EEG pattern is presented at initial onset. Early referral to an epilepsy center cannot be emphasized enough, even in situations when high-resolution brain MRI is normal.     

The varied semiology of seizures in the context of small anterior temporal encephaloceles

Aims. Small encephaloceles of the anterior temporal pole have been increasingly recognised as an underlying epileptogenic substrate in patients with medically refractory epilepsy. The current report aims to expand on the current knowledge by emphasising that seizure semiology in such patients can vary significantly. Methods. Patients were selected from an epilepsy surgery database between 2012 and 2017. Results. Of the 143 patients who underwent epilepsy surgery, six patients had a temporal encephalocele. Four of these patients had stereo-EEG implantation. Of the four patients studied, each had a seizure semiology discordant with an ictal focus in the temporal lobe. Intracranial EEG assessment demonstrated, irrespective of this semiology, seizures originated from the anterior temporal pole. Seizures were observed to rapidly propagate to the orbitofrontal cortex, insula, temporo-occipital junction, and posterior language regions. Engagement of the mesial temporal structures could occur early or late, however, a good surgical outcome was achieved following a focused lesionectomy in either situation. Conclusion. The major finding was that seizures arising from anterior temporal encephaloceles can have an extra-temporal semiology. The varied clinical semiology and the rapid propagation to seemingly distant cortical regions could be explained by the connectivity of the anterior temporal lobe.     

Ictal urinary urge indicates seizure onset in the nondominant temporal lobe

ARTICLE ABSTRACT: The authors describe six patients with medically refractory temporal lobe epilepsy whose seizures were characterized by an aura of ictal urinary urge. All seizures originated in the nondominant temporal lobe as evidenced from interictal spikes, ictal EEG, and MRI. Ictal SPECT, which was obtained in two patients, showed a hyperperfusion of the insular cortex, indicating a critical role of the insula for the generation of this symptom. Ictal urinary urge represents a new lateralizing sign indicating a seizure onset in the nondominant temporal lobe.     

Insular cortex involvement in mesiotemporal lobe epilepsy: a positron emission tomography study

Somesthetic and emotional symptoms that are common in patients with mesial temporal lobe epilepsy are usually related to hippocampo-amygdalar complex involvement. Recent stereo-electroencephalographic studies have shown a relationship between such symptoms and epileptic insular discharges. To further investigate this problem, we carried out a positron emission tomography study using fluorodeoxyglucose (18F-FDG) and flumazenil (11C-FMZ) in mesial temporal lobe epilepsy patients. The aim of our study was to assess the existence of a cortical insular involvement in order to examine its clinical correlates and the relationship between the postoperative outcome and the insular involvement. Fluorodeoxyglucose and flumazenil-positron emission tomography studies were carried out in 18 patients with mesial temporal lobe epilepsy patients. A statistical parametric mapping (SPM96) was performed to analyze the data in comparison to 18 healthy volunteers. For each set of fluorodeoxyglucose and flumazenil images a group and an individual analysis were performed. In addition, a region of interest analysis was performed to validate the results. Focusing on the metabolic abnormalities, we also investigated the role of insular cortex in the symptoms experienced by the patients and the prognostic value of insular metabolic abnormalities. Highly significant hypometabolism and BZR binding decreases were detected in the insular cortex. Results were similar using the region of interest approach. Insular involvement (mainly ipsilateral to the seizure focus) was present in 60% of the patients. Emotional symptoms correlated with hypometabolism in the anterior part of the ipsilateral insular cortex, whereas somesthetic symptoms correlated with hypometabolism in the posterior part. No relationship between postoperative outcome and ipsilateral insular hypometabolism was found. Unilateral mesial temporal lobe epilepsy is associated with insular hypometabolism and benzodiazepine receptor loss. Our results also suggest that the anterior part of the insular cortex is involved in the emotional symptoms and the posterior insular cortex is involved in the somesthetic symptoms. Hypometabolism located in the insula did not influence postoperative outcome after anterior lobectomy.     

Clinical manifestations of insular lobe seizures: a stereo-electroencephalographic study

PURPOSE: In this study, we report the clinical features of insular lobe seizures based on data from video and stereo-electroencephalographic (SEEG) ictal recordings and direct electric insular stimulation of the insular cortex performed in patients referred for presurgical evaluation of temporal lobe epilepsy (TLE). METHODS: Since our first recordings of insular seizures, the insular cortex has been included as one of the targets of stereo-electroencephalographic (SEEG) electrode implantation in 50 consecutive patients with TLE whose seizures were suspected to originate from, or rapidly to propagate to, the perisylvian cortex. In six, a stereotyped sequence of ictal symptoms associated with intrainsular discharges could be identified. RESULTS: This ictal sequence occurred in full consciousness, beginning with a sensation of laryngeal constriction and paresthesiae, often unpleasant, affecting large cutaneous territories, most often at the onset of a complex partial seizure (five of the six patients). It was eventually followed by dysarthric speech and focal motor convulsive symptoms. The insular origin of these symptoms was supported by the data from functional cortical mapping of the insula by using direct cortical stimulations. CONCLUSIONS: This sequence of ictal symptoms looks reliable enough to characterize insular lobe epileptic seizures (ILESs). Observation of this clinical sequence at the onset of seizures on video-EEG recordings in TLE patients strongly suggests that the seizure-onset zone is located not in the temporal but in the insular lobe; recording directly from the insular cortex should occur before making any decision regarding epilepsy surgery.     

Neural network underlying ictal pouting (“chapeau de gendarme”) in frontal lobe epilepsy

In order to determine the anatomical neural network underlying ictal pouting (IP), with the mouth turned down like a “chapeau de gendarme”, in frontal lobe epilepsy (FLE), we reviewed the video-EEG recordings of 36 patients with FLE who became seizure-free after surgery. We selected the cases presenting IP, defined as a symmetrical and sustained (> 5 s) lowering of labial commissures with contraction of chin, mimicking an expression of fear, disgust, or menace. Ictal pouting was identified in 11 patients (8 males; 16–48 years old). We analyzed the clinical semiology, imaging, and electrophysiological data associated with IP, including FDG-PET in 10 and SEEG in 9 cases. In 37 analyzed seizures (2–7/patient), IP was an early symptom, occurring during the first 10 s in 9 cases. The main associated features consisted of fear, anguish, vegetative disturbances, behavioral disorders (sudden agitation, insults, and fighting), tonic posturing, and complex motor activities. The epileptogenic zone assessed by SEEG involved the mesial frontal areas, especially the anterior cingulate cortex (ACC) in 8 patients, whereas lateral frontal onset with an early spread to the ACC was seen in the other patient. Ictal pouting associated with emotional changes and hypermotor behavior had high localizing value for rostroventral “affective” ACC, whereas less intense facial expressions were related to the dorsal “cognitive” ACC. Fluorodeoxyglucose positron emission tomography demonstrated the involvement of both the ACC and lateral cortex including the anterior insula in all cases. We propose that IP is sustained by reciprocal mesial and lateral frontal interactions involved in emotional and cognitive processes, in which the ACC plays a pivotal role.     

Gender and age influence in daytime and nighttime seizure occurrence in epilepsy associated with mesial temporal sclerosis

ObjectivesThe aim of this study was to analyze the daytime and nighttime seizure distribution during video-EEG monitoring in patients with epilepsy associated with unilateral mesial temporal sclerosis (MTS) and the role of gender, age, and lesion side on 24-hour seizure distribution.MethodsWe studied 167 consecutive adult (age ≥ 16 years) patients with epilepsy associated with unilateral mesial temporal sclerosis that had three or more recorded seizures during continuous video-EEG monitoring with a minimum recording time period of 24 h. Seizure onset time was classified according to occurrence in six 4-hour periods.ResultsSeven hundred thirty-five seizures were evaluated. We observed two higher seizure occurrence periods: 08:01–12:00 (p = 0.001) and 16:01–20:00 (p = 0.03). Significantly fewer seizures were observed between 0:01 and 4:00 (p = 0.01). Nonuniform seizure distribution was noted in women (p < 0.0001), in young patients (less than 45 years of age) (p < 0.0001), and in both patients with left (p = 0.03) and patients with right mesial temporal sclerosis (p = 0.008). Men presented uniform seizure occurrence distribution (p = 0.15). Women had fewer seizures than expected and fewer seizures than men between 0:01–04:00 (p < 0.0001 and p = 0.0015, respectively) and 04:01–08:00 (p = 0.01 and p = 0.03, respectively). Young patients (age < 45 years) had two seizure occurrence peaks, 08:01–12:00 (p = 0.016) and 16:01–20:00 (p = 0.004). Middle-aged/old patients (≥ 45 years) had only one seizure occurrence peak, 08:01–12:00 (p = 0.012). Young patients had more seizures than middle-aged/old patients between 16:01–20:00 (p = 0.04). No differences were noted between left and right MTS.SignificanceWe observed two seizure occurrence peaks: morning and late afternoon/evening. We encountered variations in daytime and nighttime seizure distribution according to gender and age, but not according to side of MTS. Future studies are needed to confirm these findings and to unravel the neurobiological substrate underlying daytime and nighttime variations of seizure occurrence in different age groups and between genders.     

Localizing and lateralizing value of ictal flatulence

ObjectiveAutonomic seizures have been associated with seizure onset in the temporal or insular lobe and consist of variations in blood pressure and heart rate, sweating, flushing, piloerection, hypersalivation, vomiting, spitting, and alterations in bladder and bowel functions. The aim of this study was to evaluate the localizing and lateralizing value of ictal flatulence.MethodsMedical records of patients with focal epilepsies who were monitored at the Interdisciplinary Epilepsy Center Marburg between 2006 and 2009 were reviewed for the occurrence of ictal flatulence. Clinical, electrophysiological, and imaging data were reviewed and compared with data for previously reported cases of ictal flatulence.ResultsTwo patients with ictal flatulence were identified (0.6%). In both patients, ictal flatulence was associated with a seizure pattern in the temporal lobe of the dominant hemisphere. Our cases and previously reported cases point toward activation of insular cortex because of such additional autonomic symptoms as unilateral piloerection, tachycardia, profound sweating, and flushing of the face.ConclusionsIctal flatulence is a rare manifestation of autonomic seizures and a localizing sign for temporal or/and insular lobe epilepsies. In general, ictal flatulence seems to have no lateralizing value.     

Transitional sharp waves at ictal onset – A neocortical ictal pattern

ObjectiveSome seizures are characterized by a transitional sharp wave (TShW) at ictal onset. We evaluated the clinical significance and localizing value of TShW in partial-onset seizures.MethodsWe identified and analyzed all scalp ictal recordings with a TShW at ictal onset in the Vanderbilt Epilepsy Monitoring Unit over a period of 12 months.ResultsA total of 52 ictal discharges in 13 patients started with a TShW. The center of TShW field was concordant with the final localization/lateralization, while that of the subsequent ictal discharge was concordant in only 6 patients. The subsequent rhythmic ictal discharge was non-localizing in 4 patients and misleading in the remaining 3 patients. The final localization was neocortical temporal or frontal in 11 patients, occipito-parietal in one, and undetermined in 1 patient. None of 61 ictal discharges in 15 patients with mesial temporal lobe epilepsy studied in the same time period started with a TShW.ConclusionIn this patient series, the TShW was a marker of neocortical seizure onset. The TShW field provided more accurate localization or lateralization of the ictal focus than the following rhythmic ictal discharge.SignificanceTShW at seizure onset should suggest a neocortical rather than hippocampal seizure onset.     

Role of the frontal lobes in the propagation of mesial temporal lobe seizures.

The depth ictal electroencephalographic (EEG) propagation sequence accompanying 78 complex partial seizures of mesial temporal origin was reviewed in 24 patients (15 from the University of Pittsburgh Epilepsy Center and 9 from UCLA). All patients were monitored with bilateral mesial frontal and mesial temporal depth electrodes and later received anterior temporal lobectomy. Ictal EEG records were categorized according to sequence of spread from the temporal focus to the other regions. Although propagation patterns varied both within and between patients, certain features were notable: (a) It was very common for seizure activity to spread initially to the ipsilateral frontal lobe (observed in 22 of 24 patients). (b) The most common mode of spread (15 of 24 patients) was initiating temporal lobe----ipsilateral frontal lobe----contralateral frontal lobe----contralateral temporal lobe. (c) Occasionally, seizure discharges invaded the frontal lobes but failed to invade the contralateral temporal lobe (2 of 24 patients). (d) Seizure activity occasionally invaded the contralateral temporal lobe prior to invading the frontal lobes (2 of 24 patients). Other notable features included (i) a clear tendency for mesial temporal seizure discharges initially to invade orbitofrontal (as opposed to anterior cingulate) cortex and (ii) the emergence of a period of clear asymmetry in the frontal lobes during which high-amplitude, rapid discharges were present on the side ipsilateral to the initiating temporal lobe. These results suggest that the prefrontal region, especially the orbitofrontal cortex, is strongly influenced by mesial temporal ictal activity. This region appears to be frequently involved in the propagation of seizures initiated in the mesial temporal lobe and may play a role in the interhemispheric propagation of mesial temporal seizures.     

Ictal automatisms with preserved responsiveness in a patient with left mesial temporal lobe epilepsy

PURPOSE: To describe the possible mechanism of ictal automatisms with preserved responsiveness (APRs) in a patient with left mesial temporal lobe epilepsy, which had not been reported previously. METHODS: Ictal EEGs recorded from bilateral foramen ovale electrodes with scalp-sphenoidal electrodes were analyzed in respect to the ictal semiology. RESULTS: The patient had a right hemispheric language dominance in the dextral. Electroclinical analysis revealed that the onset of oroalimentary automatisms coincided with the involvement of the left mesial and lateral temporal structures by spreading ictal discharges. The ictal discharge spreading was limited to the ipsilateral hemisphere throughout the seizure, which explained the intact consciousness and preserved responsiveness of the patient. CONCLUSIONS: This case suggests that APRs take place in seizures originating from the nondominant temporal lobe, during which ipsilateral mesial and lateral temporal structures are diffusely involved without spreading to the contralateral side.