Different localizations underlying cortical gelastic epilepsy: case series and review of literature.

BACKGROUND: Gelastic seizures (GS) are classically observed with hypothalamic hamartomas but they can also be associated with cortical epileptogenic foci. OBJECTIVE: To study the different cortical localizations associated with GS. METHODS: We reviewed the data from all patients with cortical GS investigated in our epilepsy unit from 1974 to 2012 and in the literature from 1956 to 2013. RESULTS: Sixteen cases were identified in our database and 77 in the literature. Investigations provided confident focus localization in 9 and 18, respectively. In our series, the identified foci were located in the mesial temporal structures (2 left, 1 right), lateral temporal cortex (1 right), superior frontal gyrus (1 left), and operculoinsular region [3 right (orbitofrontal or frontal operculum extending into the anterior insula) and 1 left (frontal operculum extending into the anterior insula)]. In the literature, the identified foci (13 right/5 left) were located in the temporal lobe of 4 (1 right inferior, 1 right medial and inferior, 1 right posterior middle, inferior extending posteriorly to the lingual gyrus, and 1 left middle, inferior, and medial), in the frontal lobe of 12 [10 (6 right/4 left) medial (i.e., superior, medial frontal, and/or anterior cingulate gyri), 1 lateral (right anterior inferior frontal gyrus), and 1 right medioposterior orbitofrontal cortex] and in the parietal lobe of 2 (1 left superior parietal lobule and 1 right parietal operculum) patients. CONCLUSION: Ictal laughter is a poorly lateralizing and localizing feature as it may be encountered in patients with a focus in the left or right frontal, temporal, parietal, or insular lobe.

Ictal swearing: a case series and review.

Seizures can manifest with ictal swearing but few studies have investigated the localising value of this epileptic manifestation. In this case series and review of the literature, we attempted to determine whether ictal swearing could help localise the epileptic focus. We review two previously published cases and report eight additional epileptic patients with ictal swearing for whom the epileptic focus was determined based on clinical, structural, electrophysiological, and surgical outcome data. Results indicated that ictal swearing occurs more commonly in male subjects and lateralises to the non-dominant hemisphere, but has poor localisation value, arising either from the frontal, parietal, temporal or occipital lobes in different patients. We discuss the significance of these findings. [Published with video sequences].

Anterior corpus callosotomy in multistep invasive monitoring and surgery for atonic seizures.

Identifying the epileptogenic zone (EZ) in patients with refractory nonlesional frontal lobe epilepsy is frequently challenging. Intracranial EEG (icEEG) recordings are often required to better delineate the EZ, but the presence of an extensive network of connections allowing rapid ictal spread may result in bilateral homologous regional (or extremely diffuse) electrical ictal patterns. Here, we report a case where callosotomy performed after a first nonlateralizing icEEG study allowed for adequate identification of the EZ. The patient, an 18-year-old left-handed woman with daily atonic spells, had synchronous interictal and ictal epileptic activity from both supplementary motor areas (SMAs) during icEEG. Anterior partial callosotomy localized the EZ to the right SMA, as seizures were no longer associated with mirror-image ictal activity over the left SMA. Right SMA resection led to seizure freedom (follow-up of 23 months). This case exemplifies how a partial callosotomy followed by further icEEG recordings may adequately localize the EZ when initial icEEG recordings reveal bilateral synchronous focal or regional ictal activities.

fNIRS-EEG study of focal interictal epileptiform discharges.

Functional near-infrared spectroscopy (fNIRS) acquired with electroencephalography (EEG) is a relatively new non-invasive neuroimaging technique with potential for long term monitoring of the epileptic brain. Simultaneous EEG-fNIRS recording allows the spatio-temporal reconstruction of the hemodynamic response in terms of the concentration changes in oxy-hemoglobin (HbO) and deoxy-hemoglobin (HbR) associated with recorded epileptic events such as interictal epileptic discharges (IEDs) or seizures. While most previous studies investigating fNIRS in epilepsy had limitations due to restricted spatial coverage and small sample sizes, this work includes a sufficiently large number of channels to provide an extensive bilateral coverage of the surface of the brain for a sample size of 40 patients with focal epilepsies. Topographic maps of significant activations due to each IED type were generated in four different views (dorsal, frontal, left and right) and were compared with the epileptic focus previously identified by an epileptologist. After excluding 5 patients due to the absence of IEDs and 6 more with mesial temporal foci too deep for fNIRS, we report that significant HbR (respectively HbO) concentration changes corresponding to IEDs were observed in 62% (resp. 38%) of patients with neocortical epilepsies. This HbR/HbO response was most significant in the epileptic focus region among all the activations in 28%/21% of patients.

The hybrid operculo-insular electrode: a new electrode for intracranial investigation of perisylvian/insular refractory epilepsy.

BACKGROUND: Precise localization of an epileptic focus in the perisylvian/insular area is a major challenge. The difficult access and the high density of blood vessels within the sylvian fissure have lead to poor coverage of intrasylvian (opercular and insular) cortex by available electrodes. OBJECTIVE: To report the creation of a novel electrode designed to record epileptic activity from both the insular cortex and the hidden surfaces of the opercula. METHODS: The hybrid operculo-insular electrode was fabricated by Ad-Tech Medical Instrument Corporation (Racine, Wisconsin). It was used in combination with regular subdural and depth electrodes for long-term intracranial recordings. The hybrid electrode, which contains both a depth and a strip (opercular) component, is inserted after microsurgical opening of the sylvian fissure. The depth component is implanted directly into the insular cortex. The opercular component has 1 or 2 double-sided recording contacts that face the hidden surfaces of the opercula. RESULTS: The hybrid operculo-insular electrode was used in 5 patients. This method of invasive investigation allowed including (2 patients) or excluding (3 patients) the insula as part of the epileptic focus and the surgical resection. It also allowed extending the epileptogenic zone to include the hidden surface of the frontal operculum in 1 patient. There were no complications related to the insertion of this new electrode. CONCLUSION: The new hybrid operculo-insular electrode can be used for intracranial investigation of perisylvian/insular refractory epilepsy. It can contribute to increasing cortical coverage of this complex region and may allow better definition of the epileptic focus.

Postictal breathing pattern distinguishes epileptic from nonepileptic convulsive seizures.

PURPOSE: To examine postictal breathing pattern in generalized convulsive nonepileptic seizures (GCNES) and generalized tonic-clonic seizures (GTCS) and evaluate this feature as a discriminating sign. METHODS: We reviewed the postictal breathing pattern seizures in 23 generalized tonic-clonic seizures in 15 consecutive patients with epilepsy and 24 convulsive nonepileptic seizures in 16 consecutive patients with pure psychogenic seizures. We also analyzed 21 frontal lobe hypermotor seizures (FLHS) in 9 patients with frontal lobe epilepsy. RESULTS: The breathing after GTCS was deep with prolonged inspiratory and expiratory phases, regular, and loud (except for two short seizures). The breathing after GCNES was characterized by increased respiratory rate or hyperpnea with short inspiratory and expiratory phases, as can be noted after exercise. The breathing was often irregular, with brief pauses. The altered breathing lasted longer after GTCS. The two groups differed significantly in loudness of postictal respiration, postictal snoring (only with GTCS), respiratory rate (faster for the GCNES group), and duration of altered breathing (longer after GTCS) (p < 0.00001 for all features). FLHS shared postictal breathing features of GCNES, but had other distinguishing features. CONCLUSIONS: The postictal breathing pattern can help differentiate generalized tonic-clonic seizures from nonepileptic psychogenic seizures with generalized motor activity and may be helpful to the practitioner obtaining a seizure history in the clinic setting or witnessing a seizure.

Musicogenic seizures can arise from multiple temporal lobe foci: intracranial EEG analyses of three patients.

PURPOSE: To determine the ictal-onset zone of musicogenic seizures by using intracranial EEG monitoring. METHODS: Musicogenic seizures in three patients with medically intractable musicogenic epilepsy were first localized by using noninvasive methods including, in one patient, ictal magnetoencephalography (MEG) and magnetic resonance spectroscopy (MRS). The ictal-onset zones in these patients were then further localized using by intracranial EEG monitoring, and the outcomes of the two patients who underwent epilepsy surgery were determined. RESULTS: Patient 1's musicogenic seizures localized to the right lateral temporal lobe, patient 2's originated in the right mesial temporal lobe, and patient 3's arose independently from both mesial temporal lobes. Patients 1 and 2 underwent resective epilepsy surgery and are seizure free (Engel class I). CONCLUSIONS: Musicogenic epilepsy is a heterogeneous syndrome with seizures that can arise from multiple temporal lobe foci. Patients with medically intractable musicogenic epilepsy and with unilateral ictal onset zones may be considered candidates for resective epilepsy surgery.