SUDEP in Spain: An Epilepsy Monitoring Unit based case series

Insular Role in Blood Pressure and Systemic Vascular Resistance Regulation

OBJECTIVES

The insula is a brain area involved in the modulation of autonomic responses. Previous studies have focused mainly on its heart rate regulatory function, but its role in vascular control is not well defined. Ictal/postictal blood pressure (BP) fluctuations may have a role in the pathogenesis of sudden unexpected death in epilepsy. This study aims to characterize the insular influence on vascular regulation through direct high-frequency electrical stimulation (E-stim) of different insular regions during stereo-electroencephalographic studies.

MATERIALS AND METHODS

An observational, prospective study was conducted, involving people with epilepsy who underwent E-stim of depth electrodes implanted in the insular cortex. Patients with anatomical or electrophysiological insular abnormalities, E-stim producing after discharges, or any elicited symptoms were excluded. Variations of BP and systemic vascular resistance (SVR) during the insular stimuli were analyzed, comparing them with those observed during E-stim of control contacts implanted in cortical noneloquent regions and sham stimulations.

RESULTS

Fourteen patients were included, five implanted in the right insula and nine in the left. We analyzed 14 stimulations in the right insula, 18 in the left insula, 18 in control electrodes, and 13 sham stimulations. Most right insular responses were hypertensive, whereas most left ones were hypotensive. E-stim of the right insula produced a significant BP and SVR increase, whereas the left insula induced a significant BP decrease without SVR changes. The most remarkable changes were elicited in both posterior insulas, although the magnitude of BP changes was generally low. Control and sham stimulations did not induce BP or SVR changes.

CONCLUSION

Our findings on insular stimulation suggest an interhemispheric difference in its vascular regulatory function, with a vasopressor effect of the right insula and a vasodilator effect of the left one.

[Incidence of sudden death in epilepsy (SUDEP): update and limitations]

BACKGROUND

Sudden unexpected death in epilepsy (SUDEP) is in most cases probably due to a fatal complication of tonic-clonic seizures and plays a significant role in the premature mortality of individuals with epilepsy. The reported risks of SUDEP vary considerably depending on the study population, so that an up-dated systematic review of SUDEP incidence including most recent studies is required to improve the estimated SUDEP risk and the counseling of individuals with epilepsy.

OBJECTIVE

To provide an overview of the current research landscape concerning SUDEP incidence across different patient populations and discuss potential conclusions and existing limitations.

MATERIAL AND METHODS

A systematic literature review on SUDEP incidence was conducted in MEDLINE and EMBASE, supplemented by a manual search in June 2023. Out of a total of 3324 publications, 50 were reviewed for this study.

RESULTS

The analyzed studies showed significant heterogeneity concerning cohorts, study design and data sources. Studies conducted without specific criteria and relying on comprehensive registers indicated an incidence of 0.78-1.2 per 1000 patient-years. Research providing incidences across various age groups predominantly show an increase with age, peaking in middle age.

DISCUSSION

Due to varying methods of data collection and incidence calculation, comparing between studies is challenging. The association with age might be due to an underrepresentation of children, adolescents and patients over 60 years.

CONCLUSION

Considering all age groups and types of epilepsy it is estimated that about 1 in 1000 individuals with epilepsy dies of SUDEP annually. With an assumed epilepsy prevalence of 0.6% in Germany, this could lead to more than one SUDEP case daily. Standardization of research methods is essential to gain more profound insights.

Sudden unexpected death in epilepsy: A critical view of the literature

Sudden unexpected death in epilepsy (SUDEP) is a sudden, unexpected, witnessed or unwitnessed, non-traumatic and non-drowning death, occurring in benign circumstances, in an individual with epilepsy, with or without evidence for a seizure and excluding documented status epilepticus in which postmortem examination does not reveal other causes of death. Lower diagnostic levels are assigned when cases met most or all of these criteria, but data suggested more than one possible cause of death. The incidence of SUDEP ranged from 0.09 to 2.4 per 1000 person-years. Differences can be attributed to the age of the study populations (with peaks in the 20-40-year age group) and the severity of the disease. Young age, disease severity (in particular, a history of generalized TCS), having symptomatic epilepsy, and the response to antiseizure medications (ASMs) are possible independent predictors of SUDEP. The pathophysiological mechanisms are not fully known due to the limited data available and because SUDEP is not always witnessed and has been electrophysiologically monitored only in a few cases with simultaneous assessment of respiratory, cardiac, and brain activity. The pathophysiological basis of SUDEP may vary according to different circumstances that make that particular seizure, in that specific moment and in that patient, a fatal event. The main hypothesized mechanisms, which could contribute to a cascade of events, are cardiac dysfunction (included potential effects of ASMs, genetically determined channelopathies, acquired heart diseases), respiratory dysfunction (included postictal arousal deficit for the respiratory mechanism, acquired respiratory diseases), neuromodulator dysfunction, postictal EEG depression and genetic factors.

Telemedicine for Individuals with epilepsy: Recommendations from International League Against Epilepsy Telemedicine Task Force

Worldwide, People with Epilepsy (PWE) are confronted with several barriers to face-to-face consultations. These obstacles hamper appropriate clinical follow-up and also increase the treatment gap for Epilepsy. Telemedicine holds the potential to enhance management as follow-up visits for PWE are focused on more on clinical history and counselling rather than physical examination. Besides consultation, telemedicine can also be used for remote EEG diagnostics and tele-neuropsychology assessments. In this article, the Telemedicine Task Force of the International League Against Epilepsy (ILAE) outlines recommendations regarding optimal practice in utilizing in the management of individuals with epilepsy. We formulated recommendations for minimum technical requirements, preparing for the first tele-consultation and the specificities for follow-up consultations. Special considerations are necessary for specific populations, including paediatric patients, patients who are not conversant with tele-medicine and those with intellectual disability. Telemedicine for individuals with epilepsy should be vigorously promoted with the aim of improving the quality of care and ultimately reduce the wide clinician access related treatment gap across several regions of the globe.

Sequential Semiology of Seizures and Brain Perfusion Patterns in Patients with Drug-Resistant Focal Epilepsies: A Perspective from Neural Networks

Ictal semiology and brain single-photon emission computed tomography have been performed in approaching the epileptogenic zone in drug-resistant focal epilepsies. The authors aim to describe the brain structures involved in the ictal and interictal epileptogenic network from sequential semiology and brain perfusion quantitative patterns analysis. A sequential representation of seizures was performed (n = 15). A two-level analysis (individual and global) was carried out for the analysis of brain perfusion quantification and estimating network structures from the perfusion indexes. Most of the subjects started with focal seizures without impaired consciousness, followed by staring, automatisms, language impairments and evolution to a bilateral tonic-clonic seizure (temporal lobe and posterior quadrant epilepsy). Frontal lobe epilepsy seizures continued with upper limb clonus and evolution to bilateral tonic-clonic. The perfusion index of the epileptogenic zone ranged between 0.439-1.362 (mesial and lateral structures), 0.826-1.266 in dorsolateral frontal structures and 0.678-1.507 in the occipital gyrus. The interictal epileptogenic network proposed involved the brainstem and other subcortical structures. For the ictal state, it included the rectus gyrus, putamen and cuneus. The proposed methodology provides information about the brain structures in the neural networks in patients with drug-resistant focal epilepsies.

Characterization of the Insular Role in Cardiac Function through Intracranial Electrical Stimulation of the Human Insula

OBJECTIVE

The link between brain function and cardiovascular dynamics is an important issue yet to be elucidated completely. The insula is a neocortical brain area that is thought to have a cardiac chronotropic regulatory function, but its role in cardiac contractility is unknown. We aimed to analyze the variability in heart rate and cardiac contractility after functional activation of different insular regions through direct electrical stimulation (E-stim) in humans.

METHODS

This was an observational, prospective study, including patients admitted for stereo-electroencephalographic recording because of refractory epilepsy, in whom the insular cortex was implanted. Patients with anatomical or electrophysiological insular abnormalities and those in whom E-stim produced subjective symptoms were excluded. Variations in heart rate (HR), stroke volume (SV), and cardiac output (CO) were analyzed during insular E-stim and compared with control E-stim of non-eloquent brain regions and sham stimulations.

RESULTS

Ten patients were included, 5 implanted in the right insula (52 E-stim) and 5 in the left (37 E-stim). Demographic and clinical characteristics of both groups were similar. E-stim of both right and left insulas induced a significant decrease of the CO and HR, and an increase of the SV. E-stim of control electrodes and sham stimulations were not associated with variations in cardiac function. Blood pressure and respiratory rate remained unaltered.

INTERPRETATION

Our results suggest a direct chronotropic and inotropic cardiac depressor function of the right and left insulas. The evidence of an insular direct cardiac regulatory function might open a path in the prevention or treatment of heart failure, arrhythmias, and sudden unexpected death in epilepsy. ANN NEUROL 2021;89:1172-1180.

Can We Prevent Sudden Unexpected Death in Epilepsy (SUDEP)?

Sudden unexpected death in epilepsy (SUDEP) remains an important cause of epilepsy-related mortality, especially in patients with refractory epilepsy. The exact cause is not known, but postictal cardiac, respiratory, and brainstem dysfunctions are implicated. SUDEP prevention remains a big challenge. Except for low-quality evidence of preventive effect of nocturnal supervision for SUDEP, no other evidence-based preventive modality is available. Other potential preventive strategies for SUDEP include reducing the occurrence of generalized tonic-clonic seizures using seizure detection devices, detecting cardiorespiratory distress through respiratory and heart rate monitoring devices, preventing airway obstruction (safety pillows), and reducing central hypoventilation using selective serotonin reuptake inhibitors and adenosine and opiate antagonists. However, none of the above-mentioned modalities has been proven to prevent SUDEP. The present review intends to provide insight into the available SUDEP prevention modalities.