Ictal bradycardia in a young child with focal cortical dysplasia in the right insular cortex

Heart Rate Variability in Insulo-Opercular Epilepsy

Background: We aimed to evaluate heart rate variability (HRV) changes in insulo-opercular epilepsy (IOE) and after insulo-opercular surgery. Methods: We analyzed 5-min resting HRV of IOE patients before and after surgery. Patients’ SUDEP-7 risk inventory scores were also calculated. Results were compared with age- and sex-matched patients with temporal lobe epilepsy (TLE) and healthy individuals. Results: There were no differences in HRV measurements between IOE, TLE, and healthy control groups (and within each IOE group and TLE group) in preoperative and postoperative periods. In IOE patients, the SUDEP-7 score was positively correlated with pNN50 (percentage of successive RR intervals that differ by more than 50 ms) (p = 0.008) and RMSSD (root mean square of successive RR interval differences) (p = 0.019). We stratified IOE patients into those whose preoperative RMSSD values were below (Group 1a = 7) versus above (Group 1b = 9) a cut-off threshold of 31 ms (median value of a healthy population from a previous study). In group 1a, all HRV values significantly increased after surgery. In group 1b, time-domain parameters significantly decreased postoperatively. Conclusions: Our results suggest that in IOE, HRV may be either decreased in parasympathetic tone or increased globally in both sympathetic and parasympathetic tones. We found no evidence that insulo-opercular surgeries lead to major autonomic dysfunction when a good seizure outcome is reached. The increase in parasympathetic tone observed preoperatively may be of clinical concern, as it was positively correlated with the SUDEP-7 score.

Insular seizures and epilepsies: Ictal semiology and minimal invasive surgery

PURPOSE OF REVIEW

The increased identification of seizures with insular ictal onset, promoted by the international development of stereo-electroencephalography (SEEG), has led to the recent description of larger cohorts of patients with insular or insulo-opercular epilepsies than those previously available. These new series have consolidated and extended our knowledge of the rich ictal semiology and diverse anatomo-clinical correlations that characterized insular seizures. In parallel, some experiences have been gained in the surgical treatment of insular epilepsies using minimal invasive procedures.

RECENT FINDINGS

The large majority of patients present with auras (mostly somatosensory and laryngeal) and motor signs (predominantly elementary and orofacial), an underlying focal cortical dysplasia, and an excellent postoperative seizure outcome. Many other subjective and objective ictal signs, known to occur in other forms of epilepsies, are also observed and clustered in five patterns, reflecting the functional anatomy of the insula and its overlying opercula, as well as preferential propagation pathways to frontal or temporal brain regions. A nocturnal predominance of seizure is frequently reported, whereas secondary generalization is infrequent. Some rare ictal signs are highly suggestive of an insular origin, including somatic pain, reflex seizures, choking spells, and vomiting. Minimal invasive surgical techniques have been applied to the treatment of insular epilepsies, including Magnetic Resonance Imaging-guided laser ablation (laser interstitial thermal therapy (LITT)), radiofrequency thermocoagulation (RFTC), gamma knife radiosurgery, and responsive neurostimulation. Rates of seizure freedom (about 50%) appear lower than that reported with open-surgery (about 80%) with yet a significant proportion of transient neurological deficit for LITT and RFTC.

SUMMARY

Significant progress has been made in the identification and surgical treatment of insular and insulo-opercular epilepsies, including more precise anatomo-clinical correlations to optimally plan SEEG investigations, and experience in using minimal invasive surgery to reduce peri-operative morbidity.

Focal cortical dysplasia with prolonged ictal asystole, a case report

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Focal cortical dysplasia causes refractory epilepsy with falls and syncope.

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FCD is known for ictal bradycardia and ictal asystole.

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Diagnosis and localization of the epileptogenic zone and ictal asystole can be made with simultaneous VEEG and EKG.

Introduction

Cortical dysplasia carries significant morbidities such as seizures and delayed milestones. Focal cortical dysplasia (FCD) causes refractory epilepsy with various seizure types depending on the location and extent of the dysplasia. FCD in the temporal region and the insular cortex may cause ictal bradycardia (IB) and ictal asystole (IA). Video EEG (VEEG) with simultaneous EKG recording can better diagnose these cardiac abnormalities in FCD. We describe a case of refractory epilepsy. The patient’s clinical seizures were usually followed by syncope. VEEG revealed frequent seizures some of which were associated with prolonged ictal asystole.

Results

A 15 years old female was admitted to an epilepsy monitoring unit for VEEG. There were widespread fast abnormal discharges known as FREDs with a frequency of 16–20 Hz. She developed numerous habitual seizures and syncope. Some of these were associated with an EKG change in the form of asystole. The cardiac workup was normal. MRI revealed abnormalities in bilateral insular, temporal, and right parietal lobes.

Conclusion

This case highlights the significance of:●

Fast rhythmic epileptiform discharges (FREDs) in cortical dysplasia.

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Role of video-EEG monitoring.

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Prolonged asystole and the potential role of cardiac intervention in the form of cardiac pacing and cardioneuroablation in decreasing syncope.

Indications, Techniques, and Outcomes of Robot-Assisted Insular Stereo-Electro-Encephalography: A Review

Stereo-electro-encephalography (SEEG) is an invasive, surgical, and electrophysiological method for three-dimensional registration and mapping of seizure activity in drug-resistant epilepsy. It allows the accurate analysis of spatio-temporal seizure activity by multiple intraparenchymal depth electrodes. The technique requires rigorous non-invasive pre-SEEG evaluation (clinical, video-EEG, and neuroimaging investigations) in order to plan the insertion of the SEEG electrodes with minimal risk and maximal recording accuracy. The resulting recordings are used to precisely define the surgical limits of resection of the epileptogenic zone in relation to adjacent eloquent structures. Since the initial description of the technique by Talairach and Bancaud in the 1950's, several techniques of electrode insertion have been used with accuracy and relatively few complications. In the last decade, robot-assisted surgery has emerged as a safe, accurate, and time-saving electrode insertion technique due to its unparalleled potential for orthogonal and oblique insertion trajectories, guided by rigorous computer-assisted planning. SEEG exploration of the insular cortex remains difficult due to its anatomical location, hidden by the temporal and frontoparietal opercula. Furthermore, the close vicinity of Sylvian vessels makes surgical electrode insertion challenging. Some epilepsy surgery teams remain cautious about insular exploration due to the potential of neurovascular injury. However, several authors have published encouraging results regarding the technique's accuracy and safety in both children and adults. We will review the indications, techniques, and outcomes of insular SEEG exploration with emphasis on robot-assisted implantation.

Neurosurgical anatomy of the insular cortex

OBJECTIVE

The purpose of this study was to clarify the morphology of the insular cortex focusing not only on the shape of the insula, but also on sulcal and gyral organization.

PATIENTS AND METHODS

Sixty formalin-fixed adult brain hemispheres had their insula exposed and photographed. The dimensions of each gyrus and sulcus were measured using an image analysis software. The morphometric data obtained was statistically analysed.

RESULTS

The insular cortex shape alternates between triangular and trapezoid, being the triangular shape the most common (75%). The angle between the posterior and inferior peri-insular sulcus in the trapezoid insulae had a mean range of 131.17° (SD = 12.277). A minimum of 3 and a maximum of 6 insular gyri were observed, being 5 the most common total number of gyri observed. The accessory gyrus was present in 66% of the insulae and well-developed in 38% of the cases. A statistical association between the number of gyri in the posterior lobe and the presence of a novel gyrus or a more developed accessory gyrus in the anterior lobe was found (P = 0.006). The posterior short gyrus was the longest of the short gyri (P <  0.001), followed by the anterior short gyrus (P < 0.001). The anterior long gyrus was the largest of the long gyri (P = 0.003). The contribution of each of the short gyri to the formation of the insular apex was inconstant. The most common observed apex arrangement was the combination of the anterior and of the middle short gyri.

CONCLUSIONS

This study makes a strong contribution to the understanding of the insular cortex anatomy, allowing neurosurgeons to be more capable to decide the best approach to this cortical area.

Insular resection may lead to autonomic function changes

OBJECTIVE

The aim of this study was to determine if insular damage is associated with markers of autonomic dysfunction.

METHODS

We studied patients who underwent temporal lobe and/or insular resections for epilepsy surgery between April 2010 and June 2015 at University Hospitals Cleveland Medical Center (UHCMC). Presurgical T1-weighted MPRAGE, standard T1, T2 and FLAIR sequences were compared with postsurgical MRI by a neuroradiologist and classified as type 0 (no involvement of insula), type 1 (minimal involvement of insular margin), type 2 (insular involvement <25%), and type 3 (insular involvement ≥25%). Analysis of heart rate variability (HRV) was carried out in pre- and postoperative video-electroencephalography (vEEG) recording. Time-domain parameters were calculated: (mean of the RR intervals (MNN), root mean square difference of successive RR intervals (RMSSD), standard deviation of the RR intervals (SDNN), and coefficient of variation (CV)). In addition, frequency-domain parameters were calculated: low frequency (LF), high frequency (HF), and low frequency/high frequency (LF/HF).

RESULTS

Twenty-one patients (14 females) with mean age of 36.2 ± 14.4 years (30; 22-75) were studied. Insular involvement was classified as type 0 (4 patients [19%]), type 1 (9 [43%]), type 2 (7 [33%]), and type 3 (1 [5%]). Significant decrease in RMSSD (p = 0.025) and CV (p = 0.008) was seen in insular damage types 2 and 3 compared with no or minimal insular involvement (types 0 and 1). Right-sided resections were associated with increase in LF power (p = 0.010) and the LF/HF ratio (p = 0.017).

CONCLUSIONS

This study indicates that insular resection may lead to autonomic function changes.

How the insula speaks to the heart: Cardiac responses to insular stimulation in humans

Despite numerous studies suggesting the role of insular cortex in the control of autonomic activity, the exact location of cardiac motor regions remains controversial. We provide here a functional mapping of autonomic cardiac responses to intracortical stimulations of the human insula. The cardiac effects of 100 insular electrical stimulations into 47 epileptic patients were divided into tachycardia, bradycardia, and no cardiac response according to the magnitude of RR interval (RRI) reactivity. Sympathetic (low frequency, LF, and low to high frequency powers ratio, LF/HF ratio) and parasympathetic (high frequency power, HF) reactivity were studied using RRI analysis. Bradycardia was induced by 26 stimulations (26%) and tachycardia by 21 stimulations (21%). Right and left insular stimulations induced as often a bradycardia as a tachycardia. Tachycardia was accompanied by an increase in LF/HF ratio, suggesting an increase in sympathetic tone; while bradycardia seemed accompanied by an increase of parasympathetic tone reflected by an increase in HF. There was some left/right asymmetry in insular subregions where increased or decreased heart rates were produced after stimulation. However, spatial distribution of tachycardia responses predominated in the posterior insula, whereas bradycardia sites were more anterior in the median part of the insula. These findings seemed to indicate a posterior predominance of sympathetic control in the insula, whichever the side; whereas the parasympathetic control seemed more anterior. Dysfunction of these regions should be considered when modifications of cardiac activity occur during epileptic seizures and in cardiovascular diseases.

The Insula and Its Epilepsies

Insular seizures are great mimickers of seizures originating elsewhere in the brain. The insula is a highly connected brain structure. Seizures may only become clinically evident after ictal activity propagates out of the insula with semiology that reflects the propagation pattern. Insular seizures with perisylvian spread, for example, manifest first as throat constriction, followed next by perioral and hemisensory symptoms, and then by unilateral motor symptoms. On the other hand, insular seizures may spread instead to the temporal and frontal lobes and present like seizures originating from these regions. Due to the location of the insula deep in the brain, interictal and ictal scalp electroencephalogram (EEG) changes can be variable and misleading. Magnetic resonance imaging, magnetic resonance spectroscopy, magnetoencephalography, positron emission tomography, and single-photon computed tomography imaging may assist in establishing a diagnosis of insular epilepsy. Intracranial EEG recordings from within the insula, using stereo-EEG or depth electrode techniques, can prove insular seizure origin. Seizure onset, most commonly seen as low-voltage, fast gamma activity, however, can be highly localized and easily missed if the insula is only sparsely sampled. Moreover, seizure spread to the contralateral insula and other brain regions may occur rapidly. Extensive sampling of the insula with multiple electrode trajectories is necessary to avoid these pitfalls. Understanding the functional organization of the insula is helpful when interpreting the semiology produced by insular seizures. Electrical stimulation mapping around the central sulcus of the insula results in paresthesias, while stimulation of the posterior insula typically produces painful sensations. Visceral sensations are the next most common result of insular stimulation. Treatment of insular epilepsy is evolving, but poses challenges. Surgical resections of the insula are effective but risk significant morbidity if not carefully planned. Neurostimulation is an emerging option for treatment, especially for seizures with onset in the posterior insula. The close association of the insula with marked autonomic changes has led to interest in the role of the insula in sudden unexpected death in epilepsy and warrants additional study with larger patient cohorts.

Ictal piloerection is associated with high-grade glioma and autoimmune encephalitis-Results from a systematic review

PURPOSE

To comprehensively analyze ictal piloerection (IP) in a large number of subjects.

METHODS

We performed a systematic review on case report studies of patients diagnosed with IP (1929-2017) with additional cases included from the Department of Neurology of University of Pécs, the National Institute of Clinical Neurosciences, and Odense University Hospital. Each included case was characterized regarding patient history, IP seizure characteristics, diagnostic work-up, and therapy. Comparative analyses were also carried out based on sex and pathology.

RESULTS

Altogether, 109 cases were included. We observed a strong male predominance (p < 0.001). The mean age at onset of epilepsy was 39.5 ± 20.7 years (median: 38, IQR:24-57). The seizure onset zone was temporal (p < 0.001), and was lateralized to the ipsilateral hemisphere in unilateral localization (p = 0.001). The seizure was accompanied by cold shiver in 53%, and by other autonomic symptoms in 47% of cases. In 53% of patients, IP never progressed into complex partial or generalized tonic-clonic seizure; 16% of the patients reported occasional, and 31% regular generalization. Seizure frequency was higher among females (median:25/day, IQR:3-60) than among males (median:3/day, IQR:1-11) (p = 0.017). The two most common underlying pathologies were limbic encephalitis (23%) and astrocytoma (23%, among them 64% WHO III-IV astrocytoma).

CONCLUSION

IP was particularly associated with autoimmune encephalitis and high-grade glioma, suggesting IP's particular clinical importance in directing diagnostic work-up.

Insular epilepsy surgery

Since it was originally described nearly 70 years ago, insular epilepsy has been increasingly recognized and may explain failures after apparently well-planned operations. We review the history of awareness of the phenomenon, techniques for its assessment, and its surgical management. Insular epilepsy can mimic features of frontal, parietal, or temporal seizures. It should be considered when a combination of somatosensory, visceral, and motor symptoms is observed early in a seizure. Extraoperative intracranial recordings are required to accurately diagnose insular seizures. Stereo-electroencephalography (EEG) or craniotomy with implantation of surface and depth electrodes have been used successfully to identify insular onset of seizures. Surgical resection of an insular focus may be performed with good success and acceptable risk.

Left-insular damage, autonomic instability, and sudden unexpected death in epilepsy

We analyzed the only two sudden unexpected death in epilepsy (SUDEP) cases from 320 prospectively recruited patients in the three-year Prevention and Risk Identification of SUDEP Mortality (PRISM) project. Both patients had surgically refractory epilepsy, evidence of left insular damage following previous temporal/temporo-insular resections, and progressive changes in heart rate variability (HRV) in monitored evaluations prior to death. Insular damage is known to cause autonomic dysfunction and increased mortality in acute stroke. This report suggests a possible role for the insula in the pathogenesis of SUDEP. The presence of intrinsic insular lesions or acquired insular damage in patients with refractory epilepsy may be an additional risk factor for SUDEP.

Ictal 99mTc-Ethyl Cysteinate Dimer SPECT Findings of a Girl With Refractory Localization-Related Epilepsy Who Developed Transient Ictal Bradycardia

Ictal bradycardia, which is considered to be one of the causes of sudden unexplained death in epilepsy, is rare. A 10-year-old girl with focal cortical dysplasia in her right centroparietal region developed transient ictal bradycardia during cluster seizures. Brain magnetic resonance imaging demonstrated a high signal intensity lesion adjacent to the focal cortical dysplasia lesion. Ictal ^99mTc-ethyl cysteinate dimer single-photon emission computed tomography (SPECT) detected hyperperfusion in an area containing the high signal intensity lesion, which was located close to the insular cortex. Since the hyperperfusion zone observed on SPECT was considered to reflect seizure propagation, it is possible that the ictal bradycardia experienced in the present case was caused by the following mechanism: The repetitive seizure activity caused the high-intensity lesion seen on MRI to expand into the right insular cortex, which controls cardiac rhythm, resulting in ictal bradycardia.

Suppression of the auditory N1-component for heartbeat-related sounds reflects interoceptive predictive coding

Although many studies have elucidated the neurocognitive mechanisms supporting the processing of externally generated sensory signals, less is known about the processing of interoceptive signals related to the viscera. Drawing a parallel with research on agency and the perception of self-generated action effects, in the present EEG study we report a reduced auditory N1 component when participants listened to heartbeat-related sounds compared to externally generated sounds. The auditory suppression for heartbeat sounds was robust and persisted after controlling for ECG-related artifacts, the number of trials involved and the phase of the cardiac cycle. In addition, the auditory N1 suppression for heartbeat-related sounds had a comparable scalp distribution as the N1 suppression observed for actively generated sounds. This finding indicates that the brain automatically differentiates between heartbeat-related and externally generated sounds through a process of sensory suppression, suggesting that a comparable predictive mechanism may underlie the processing of heartbeat and action-related information. Extending recent behavioral data about cardio-visual integration, the present cardio-auditory EEG data reveal that the processing of sounds in auditory cortex is systematically modulated by an interoceptive cardiac signal. The findings are discussed with respect to theories of interoceptive awareness, emotion, predictive coding, and their relevance to bodily self-consciousness.

Definition of a stereotactic 3-dimensional magnetic resonance imaging template of the human insula

BACKGROUND

This study proposes a 3-dimensional (3-D) template of the insula in the bicommissural reference system with posterior commissure (PC) as the center of coordinates.

OBJECTIVE

Using the bicommissural anterior commissure (AC)-PC reference system, this study aimed to define a template and design a method for the 3-D reconstruction of the human insula that may be used at an individual level during stereotactic surgery.

METHODS

Magnetic resonance imaging (MRI)-based morphometric analysis was performed on 100 cerebral cortices with normal insulae based on a 3-step procedure: Step 1: AC-PC reference system-based reconstruction of the insula from the 1-mm thick 3-D T1-weighted MRI slices. Step 2: Digitalization and superposition of the data obtained in the 3 spatial planes. Step 3: Representation of pixels as colors on a scale corresponding to the probability of localization of each insular anatomic component.

RESULTS

The morphometric analysis of the insula confirmed our previously reported findings of a more complex shape delimited by 4 peri-insular sulci. A very significant correlation between the coordinates of the main insular structures and the length of AC-PC was demonstrated. This close correlation allowed us to develop a method that allows the 3-D reconstruction of the insula from MRI slices and only requires the localization of AC and PC. This process defines an area deemed to contain insula with 100% probability.

CONCLUSION

This 3-D reconstruction of the insula should be useful to improve its localization and other cortical areas and allow the differentiation of insular cortex from opercular cortex.

A gut feeling about insular seizures

A 43-year-old man presented to the Prince of Wales Hospital, Sydney, New South Wales, Australia, after experiencing his first tonic-clonic seizure. For the previous 2 years he had undergone gastroenterological investigation of episodes of gagging associated with hypersalivation and lachrymation, occurring three or four times per week. EEG showed epileptiform discharges in the right anterior temporal region; brain MRI revealed a lesion in the right insular cortex. Video-EEG telemetry demonstrated that the episodes of gagging were focal seizures. Antiepileptic drug therapy resulted in no further episodes occurring over the next 10 months.

Anatomofunctional organization of the insular cortex: a study using intracerebral electrical stimulation in epileptic patients

PURPOSE

Different lines of evidence suggest that the insular cortex has many important functional roles. Direct electrical stimulation (ES) of the human insular cortex during surgical procedures for epilepsy, functional imaging techniques, and lesion studies also occasionally induces clinical responses.

METHODS

In this study, we evaluated 25 patients with drug-refractory focal epilepsy by stereotactically implanting at least one electrode into the insular cortex using an oblique approach (transfrontal or transparietal). One hundred twenty-eight insular sites (each situated between two contiguous contacts within the same electrode) were examined within the gyral substructures. We located each stimulation site by fusing preimplantation three-dimensional (3D) magnetic resonance imaging (MRI) images with the postimplantation 3D computed tomography (CT) scans that revealed the electrode contacts.

RESULTS

Sixty-seven stimulations induced at least one clinical response. Stimulation from within the insular cortex evoked 83 responses, without evidence of afterdischarge in the insular or extrainsular regions. We classified the principal responses as sensory (paresthesias and localized warm sensations), motor, pain, auditory, oropharyngeal, speech disturbances (including speech arrest and reduced voice intensity) and neurovegetative phenomena, such as facial reddening, generalized sensations of warmth or cold, hypogastric sensations, anxiety attacks, respiratory accelerations, sensations of rotation, and nausea.

CONCLUSIONS

These findings may indicate a functional specificity for the insular gyri and show the need for exploring this structure during invasive presurgical evaluation of epileptic patients according to seizure manifestations.

Sudden unexpected death in epilepsy

Epilepsy is one of the most common serious neurological conditions worldwide, and sudden unexpected death in epilepsy (SUDEP) is the main cause of epilepsy-related death. Although the exact pathophysiological causes of SUDEP are still unknown, potential risk factors include young age of epilepsy onset, duration of epilepsy, frequently recurrent seizures, winter temperatures and cardiac abnormalities such as arrhythmias during and between seizures. Unfortunately available pharmacological treatment for epilepsy remains limited in seizure control and consequently in SUDEP control, so alternative treatment should be considered in patients with refractory epilepsy. This article will revisit the possible related causes and preventative actions for SUDEP.

Non ruptured MCA aneurysms presenting with insular related symptoms

OBJECTIVE

To present a new semiological description of unruptured middle cerebral artery (MCA) aneurysms.

METHODS

We present a series of three MCA aneurysms presenting with progressive or paroxystic somatosensory symptoms in combination with visceral, motor, language or autonomic symptoms.

RESULTS

A surgical approach was proposed for two aneurysms, and both patients experienced complete resolution of their symptoms. The third aneurysm was successfully excluded by endovascular coiling but the symptoms persisted.

CONCLUSIONS

To our knowledge this is the first description of unruptured aneurysms presenting with insular-related symptoms.

Description of sulcal organization of the insular cortex

PURPOSE

To study the morphology of the gyri and sulci of the insular region.

MATERIALS AND METHODS

This study examined 20 formalin-fixed cerebral hemispheres (10 right and 10 left). Observations described: the peri-insular sulci, anatomical variations in the insular sulci and gyri, and the relationships between the central insular sulcus and the central cerebral sulcus and the anatomy of the insular arteries.

RESULTS

Each insula had a trapezoid shape, surrounded by four peri-insular sulci (anterior, superior, posterior, and inferior). We differentiated the posterior peri-insular sulcus from the inferior peri-insular sulcus. These two sulci have two different axes separated by a clear angle. The central insular sulcus divides the insula into two parts. The anterior insula includes three short gyri and the anterior insular pole. The posterior insula includes two long gyri and the posterior insular pole. This structure defines two intra-insular opercula. In 60% of cases, the superior extremity of the central insular sulcus is in direct continuity with the inferior extremity of the cerebral central sulcus. The superior branch of the middle cerebral artery supplies the majority of the anterior insular gyri, and the inferior branch supplies the majority of the posterior insular gyri.

CONCLUSIONS

This study details the morphology of each insular structure (gyri, sulci and poles), data which could facilitate surgical access to this deep cortical area and assist in future work correlating anatomy with function.

Microsurgery of epileptic foci in the insular region

OBJECT

The insular region has long been neglected in the investigation and treatment of refractory epilepsy. Surgery in the insular region is rarely performed because of the risk of injury to the opercula, the arteries transiting on the surface of the insula, and the deep structures such as the basal ganglia and the internal capsule. This study was undertaken to report the results of insular surgery using modern microsurgical techniques in patients with epilepsy.

METHODS

The authors performed a retrospective study of cases involving patients who underwent surgery for insular lesions associated with epilepsy over the last 10 years. In the majority of patients, intracranial electrodes were implanted with neuronavigation guidance to confirm the localization of the epileptic foci.

RESULTS

Nine patients underwent insular surgery: 7 for refractory epilepsy with no tumor and 2 for tumors associated with seizures. Four of the resections were performed in the left hemisphere. After an average follow-up of 54 months (range 14-122 months), Engel Class IA outcome had been achieved in 6 of 7 cases in the Epilepsy Surgery Group. The remaining patient had an Engel Class III outcome after partial insular resection but later became seizurefree (Engel Class IA) following insular Gamma Knife surgery. Postoperatively, the majority of patients suffered from minor reversible hemipareses that disappeared completely within a few months. There was no surgical mortality.

CONCLUSIONS

Insular surgery is both safe and beneficial when it is well planned and performed with modern microsurgical techniques and good anatomical knowledge. Insulectomy is associated with little permanent morbidity and a high rate of seizure control. To the authors' knowledge, this is the first series of insulectomies predominantly performed for refractory epilepsy since those performed by Penfield.

Apnoea in relation to neonatal temporal lobe haemorrhage

BACKGROUND

Six term newborns presented with apnoea and temporal lobe haemorrhage.

AIM

In this observational study, we described involvement of the limbic system in apnoeic term newborns with temporal lobe injury.

METHODS

Six term newborns presented to the neonatal care unit with apnoea within the first 2 days of life. Ultrasound (US) and MRI of the brain were obtained in the first week of life.

RESULTS

Apnoea was related to temporal lobe haemorrhage in all. During apnoeic periods four had focal epileptic activity on EEG. All lesions were detected first with US. On MRI, haemorrhages were located in the parenchyma, the subdural and/or subarachnoid space. Three haemorrhages were surrounded by infarction in the temporal lobe. In three infants hippocampus and mesial temporal cortex were affected. In two basal temporal cortex only was involved. Vascular anomalies were excluded by MRA, serial MRI or serial US with Doppler imaging.

CONCLUSION

Term infants with seizure associated apnoea may present with haemorrhage and/or infarction to hippocampus, mesial and basal temporal cortex. This study supports the existence and possible disruption of descending influences from the temporal cortex and/or amygdala on brainstem breathing centres in the term newborn.

[Does epilepsy surgery really lower mortality?]

Patients with epilepsy suffer from a two to three fold increased death rate as compared to age and sex matched control population. This increased risk culminate to five fold in patients with drug resistant partial epilepsy eligible for epilepsy surgery, with the majority of deaths classified as sudden unexpected death in epilepsy (SUDEP). The pathophysiology of SUDEP remains uncertain, but all witnessed cases occurred during or immediately after a seizure. Several studies have evaluated the impact of epilepsy surgery on the risk of seizure related death and SUDEP. Four series have concentrated on operated patients, and have compared the death rates in those seizure free and non seizure free post-operatively. Three of these studies reported a significantly lower risk of SUDEP in patients cured by surgery as compared to those still seizing. Four other series have compared the mortality in surgically versus medically treated patients with refractory partial epilepsy. Three of these studies failed to show any significant difference in death or SUDEP rates between operated and and non operated patients. All the above series suffer various types of methological limitations, hampering any definite conclusion regarding the impact of epilepsy surgery on mortality. The launching of novel and large multicentric studies, which address the pitfalls of prior series, should allow to provide conclusive results within the next three years.

Ictal bradycardia and asystole: an uncommon cause of syncope

We report on two patients with recurrent syncope secondary to ictal bradyarrhythmias, triggered by partial epileptic seizures with atypical, stereotyped auras. Ictal bradyarrhythmias are potentially lethal, and likely originate from the involvement of limbic autonomic regions. The appropriate treatment is double-headed, including an antiepileptic drug and the implantation of a pacemaker.

Panayiotopoulos Syndrome: An Important Electroclinical Example of Benign Childhood System Epilepsy

As a result of the converging evidence from multiple large independent studies, Panayiotopoulos syndrome (PS) is now formally recognized as a distinct clinical entity within the spectrum of benign focal epilepsies of childhood. Clinically, PS is manifested by predominantly autonomic seizures and electrographically with multifocal interictal spikes, while the few published ictal recordings have documented onsets of variable lobar topography. These typical electroclinical features do not allow straightforward assignment to a distinctive cortical area, rendering the term "focal"--as we currently understand it--problematic. This is a critical review of the clinical and EEG features of PS, focusing on those characteristics that may shed some light on its so far elusive pathophysiology. We also explore its electroclinical similarities to other idiopathic "focal" epilepsies and its differences to symptomatic focal epilepsies that may also manifest with autonomic ictal symptoms and signs. This methodology allows the formation of a rational hypothesis on the pathophysiology of PS that seems to be emerging as a good model for the so-called "system" (nonsymptomatic) epilepsies, with potentially important taxonomic implications.

The ictal bradycardia syndrome: localization and lateralization

PURPOSE

Previous studies have established the importance of the insular cortex and temporal lobe in cardiovascular autonomic modulation. Some investigators, based on the results of cortical stimulation response, functional imaging, EEG recordings of seizures, and lesional studies, have suggested that cardiac sympathetic and parasympathetic function may be lateralized, with sympathetic representation lateralized to the right insula, and parasympathetic, to the left. These studies have suggested that ictal bradycardia is most commonly a manifestation of activation of the left temporal and insular cortex. However, the evidence for this is inconsistent. We sought to assess critically the predictable value of ictal bradycardia for seizure localization and lateralization.

METHODS

In this study, we reviewed the localization of seizure activity in 13 consecutive patients with ictal bradycardia diagnosed during prolonged video-EEG monitoring at Mayo Clinic Rochester. The localization of electrographic seizure activity at seizure onset and bradycardia onset was identified in all patients. In addition, we performed a comprehensive review of the ictal bradycardia literature focusing on localization of seizure activity in ictal bradycardia cases.

RESULTS

All occurrences of ictal bradycardia in the 13 identified patients were associated with temporal lobe-onset seizures. However, no consistent lateralization of seizure activity was found at onset of seizure activity or at onset of bradycardia in this population. Seizure activity was bilateral at bradycardia onset in nine of 13 patients. The results from the literature review also showed that a predominance of patients had bilateral activity at bradycardia onset; however, more of the ictal bradycardia cases from the literature had left hemispheric localization of seizure onset.

CONCLUSIONS

Ictal bradycardia most often occurs in association with bilateral hemispheric seizure activity and is not a consistent lateralizing sign in localizing seizure onset. Our data do not support the existence of a strictly unilateral parasympathetic cardiomotor representation in the left hemisphere, as has been suggested.

Sudden unexpected death in epilepsy: from mechanisms to prevention

PURPOSE OF REVIEW

To discuss the pathophysiology and potential prevention of sudden unexpected death in epilepsy.

RECENT FINDINGS

Long-term electrocardiogram monitoring over several months has detected ictal asystole in three out of 20 (15%) patients with refractory epilepsy, suggesting that high-risk ictal arrhythmias occur in a greater proportion of patients with refractory epilepsy than previously thought. In case-control studies, sudden unexpected death in epilepsy was found to be associated with frequent generalized tonic-clonic seizures and greater ictal maximal heart rate, especially during nocturnal attacks. Conversely, supervision at night was associated with a lower risk of occurrence. The impact of epilepsy surgery on the risk of death and sudden unexpected death in epilepsy remains unclear, with comparable long-term survival in an epilepsy surgery cohort compared with a matched population of patients with refractory epilepsy who did not undergo surgery. Previous results may have been partly confounded by the association observed between preoperative decreased heart rate variability and poor postoperative seizure outcome.

SUMMARY

Ictal arrhythmias may represent a more prevalent cause of sudden unexpected death in epilepsy than previously thought. No clear recommendations have emerged from the literature regarding the most appropriate therapeutic strategies to prevent the event, apart from the supervision at night of patients with refractory epilepsy.

Does epilepsy surgery lower the mortality of drug-resistant epilepsy?

Drug-resistant epilepsy has proved to be associated with an increased standardized mortality ratio (SMR), primarily due to seizure-related fatalities including sudden unexpected death (SUDEP). Recent studies have suggested that the surgical cure of temporal lobe epilepsy (TLE) was likely to normalize the SMR of patients suffering from refractory TLE. However, these studies raise a number of methodological issues, which have not always been fully addressed. Some conclusions have relied on previously reported data, indicating a SMR of approximately 5, and a SUDEP incidence of 9/1000 patient-years in drug-resistant epilepsy. In fact, as shown in this review, SMR varied considerably, from 2 to 16, in the various series of patients with refractory epilepsy, whereas the average SUDEP incidence in the same populations was calculated at 3.7/1000 patient-years. Other conclusions were based on the comparison of either surgically and medically treated patients, or cured and non-cured operated patients. In both situations, the two groups included a different proportion of excellent and poor surgical candidates. The biological differences that distinguish these two populations might explain part of the differences observed in their mortality rate, regardless of the effect of surgery. In particular, temporal-plus epilepsies involving the insula, the frontal orbital, or the frontal operculum region, might favour ictal arrhythmias, central apnoea and secondary generalization, which in turn would increase the risk of SUDEP. Future studies are thus warranted to specifically address these issues.