The occurrence and characteristics of auras in a large epilepsy cohort

Déjà vu in idiopathic generalized epilepsy: A systematic review

INTRODUCTION

Déjà vu (DV), a French term meaning "already seen," refers to inappropriate sensation of familiarity in the present moment, as if it had been experienced before without a specific recollection of when or where. Traditionally, DV has been closely associated with focal seizures originating from the medial temporal lobe. However, there are occasional reports of DV occurring in idiopathic generalized epilepsies (IGEs). The objective of our study was to assess the presence and frequency of DV in individuals with IGE.

METHODS

We used the Preferred Reporting Items for Systematic Review and Meta-Analysis for protocols (PRISMA-P) and searched PubMed and Embase from January 2000 to July 2022.

RESULTS

5 studies were included with a total of 1177 IGE and 1026 with temporal lobe epilepsy (TLE) patients. The frequency of DV in IGE ranged from 0 to 11 %, and the average was 3 %, compared to 19.6 % in TLE. Broadly, 40 % of patients with IGE reported some type of aura. EEG correlation of DV in IGE was not appropriately evaluated in the studies.

CONCLUSION

Clinicians should be aware that individuals with IGE may experience DV and other types of auras. Recognizing these auras is crucial in order to avoid misdiagnosing IGE as focal epilepsy. This is important to prevent unnecessary investigations and incorrect treatment decisions.

Yield of video electro encephalography for phase 1 pre-surgical evaluation of drug resistant epilepsy in 1200 adults: retrospective study from a tertiary center situated in a lower-middle-income country

INTRODUCTION

Video Electroencephalography (VEEG) is crucial for presurgical evaluation of Drug Refractory Epilepsy (DRE). The yield of VEEG in large volume centers, particularly those situated in Low-and Middle-Income countries (LMIC) is not well studied.

METHODOLOGY

We studied 1200 adults with drug resistant focal epilepsy whose seizures were recorded during VEEG in the epilepsy monitoring unit. VEEG review and analysis was done independently by trained epileptologists. Video EEG and MRI data were examined for concordance in order to generate a hypothesis for the presumed epileptogenic zone.

RESULTS

Analysis of seizure semiology provided information on the symptomatogenic zone in most cases except for 33 (2.75%) patients. A total of 1050 (87.5%) patients showed interictal epileptiform discharges (IEDs) with most (58.3%) showing unilateral IEDs. Most patients (n = 1162, 96.83%) showed ictal EEG discharges of which 951(81.8%) had unilateral ictal onset. Abnormal MRI was seen in 978 (81.5%) patients. Concordance of electroclinical data obtained by analysis of VEEG with MRI abnormality could be established in most patients (63%). Concordance was higher for patients with ictal onset from temporal regions (83.71%) as compared to posterior cortex (55.4%) and frontal regions (43.5%.) CONCLUSION: This study highlights the high yield of VEEG in phase 1 presurgical evaluation in DRE. Systematic evaluation of data from VEEG provided lateralizing and localizing information in most cases. Concordance between VEEG and MRI findings was noted in most patients. These findings support steps to increase referral for pre-surgical evaluation in DRE.

Somatosensory Auras in Epilepsy: A Narrative Review of the Literature

An aura is a subjective experience felt in the initial phase of a seizure. Studying auras is relevant as they can be warning signs for people with epilepsy. The incidence of aura tends to be underestimated due to misdiagnosis or underrecognition by patients unless it progresses to motor features. Also, auras are associated with seizure remission after epilepsy surgery and are an important prognostic factor, guiding the resection site and improving surgical outcomes. Somatosensory auras (SSAs) are characterized by abnormal sensations on one or more body parts that may spread to other parts following a somatotopic pattern. The occurrence of SSAs among individuals with epilepsy can range from 1.42% to 80%. The upper extremities are more commonly affected in SSAs, followed by the lower extremities and the face. The most common type of somatosensory aura is paresthetic, followed by painful and thermal auras. In the primary somatosensory auras, sensations occur more commonly contralaterally, while the secondary somatosensory auras can be ipsilateral or bilateral. Despite the high localizing features of somatosensory areas, cortical stimulation studies have shown overlapping sensations originating in the insula and the supplementary sensorimotor area.

Elucidating the visual phenomena in epilepsy: A mini review

Epilepsy is one of the most recognizable neurological diseases, globally. Epilepsy may be accompanied by various complications, including vision impairments, which may severely impact one's quality of life. These visual phenomena may occur in the preictal, ictal and/or postictal periods of seizures. Examples of epilepsy associated visual phenomena include visual aura, visual hallucinations, transient visual loss and amaurosis (blindness). These ophthalmologic signs/symptoms of epilepsy may be temporary or permanent and may vary depending of the type of epilepsy and location of the seizure foci (occipital or temporal lobe). Some visual phenomena may even be utilized to diagnose the epilepsy type, although solely depending on visual symptoms for diagnosis may lead to mistreatment. Some antiseizure medications (ASMs) may also contribute to certain visual disturbances, thereby impacting its therapeutic efficiency for patients with epilepsy (PWE). Although the development of visual comorbidities has been observed diversely among PWE, there may still be a lack of understanding on their relevance and manifestation in epilepsy, which may contribute to the rate of misdiagnosis and the current scarcity in therapeutic relieve. Therefore, this mini narrative review aimed to discuss the common epilepsy associated visual phenomena, based on the available literature. This review also showcased the relationship between the type of visual complications and the site of seizure onset, as well as compared the visual phenomena between occipital lobe epilepsy and temporal lobe epilepsy. Evaluation of these findings may be crucial in reducing the risk of permanent seizure/epilepsy related vision deficits among PWE.

Epilepsy and the gut: Perpetrator or victim?

The brain and the gut are linked together with a complex, bi-path link known as the gut-brain axis through the central and enteric nervous systems. So, the brain directly affects and controls the gut through various neurocrine and endocrine processes, and the gut impacts the brain via different mechanisms. Epilepsy is a central nervous system (CNS) disorder with abnormal brain activity, causing repeated seizures due to a transient excessive or synchronous alteration in the brain’s electrical activity. Due to the strong relationship between the enteric and the CNS, gastrointestinal dysfunction may increase the risk of epilepsy. Meanwhile, about 2.5% of patients with epilepsy were misdiagnosed as having gastrointestinal disorders, especially in children below the age of one year. Gut dysbiosis also has a significant role in epileptogenesis. Epilepsy, in turn, affects the gastrointestinal tract in different forms, such as abdominal aura, epilepsy with abdominal pain, and the adverse effects of medications on the gut and the gut microbiota. Epilepsy with abdominal pain, a type of temporal lobe epilepsy, is an uncommon cause of abdominal pain. Epilepsy also can present with postictal states with gastrointestinal manifestations such as postictal hypersalivation, hyperphagia, or compulsive water drinking. At the same time, antiseizure medications have many gastrointestinal side effects. On the other hand, some antiseizure medications may improve some gastrointestinal diseases. Many gut manipulations were used successfully to manage epilepsy. Prebiotics, probiotics, synbiotics, postbiotics, a ketogenic diet, fecal microbiota transplantation, and vagus nerve stimulation were used successfully to treat some patients with epilepsy. Other manipulations, such as omental transposition, still need more studies. This narrative review will discuss the different ways the gut and epilepsy affect each other.

Aura: epilepsy vs. functional (psychogenic) seizures

PURPOSE

To compare auras between three groups of people with seizures [i.e., Idiopathic generalized epilepsies (IGE) vs. Temporal lobe epilepsy (TLE) vs. Functional seizures (FS)].

METHODS

All patients, 10 years of age or older, with a diagnosis of IGE, TLE, or FS were prospectively registered in an electronic database and retrospectively studied at the outpatient epilepsy clinic at Shiraz University of Medical Sciences, Shiraz, Iran, from 2008 until 2020.

RESULTS

One thousand and three hundred ninety-one patients were studied (480 with IGE, 617 with TLE, and 294 with FS). Among patients with TLE, 63.5% of individuals reported auras; this figure was 68% in the FS and 12.7% in the IGE groups (p < 0.00001). Odds ratio of having auras in the TLE group compared with the IGE group was 11.96 (95% CI: 8.73-16.39; p = 0.0001). Odds ratio of having auras in the TLE group compared with the FS group was 0.81 (95% CI: 0.61-1.10; p = 0.1840). Odds ratio of having auras in the FS group compared with the IGE group was 14.61 (95% CI: 10.15-21.02; p = 0.0001). The following auras were more frequent among patients with TLE: emotional, cognitive, epigastric, and olfactory/gustatory. The following auras were more frequent among patients with FS: headache and dizziness/vertigo.

CONCLUSION

Auras are not specific to focal epilepsies. Future studies should investigate auras in large cohorts of patients with focal or generalized epilepsies and also those with FS to determine the exact clinical value of each aura.

Ictal injury: Epilepsy vs. functional (psychogenic) seizures

OBJECTIVE

The aim of the current study was to compare the risk and also the types of ictal injuries in three groups of people with seizures [i.e., IGE vs. TLE vs. FS].

METHODS

This was a retrospective study. All patients with an electro-clinical diagnosis of IGE, TLE, or FS were recruited at the outpatient epilepsy clinic at Shiraz University of Medical Sciences, Shiraz, Iran, from 2008 until 2020. Age, sex, age at seizure onset, seizure type(s), and occurrence of ictal injury at any time since the onset of the seizures and its characteristics were registered routinely for all patients at the time of the first visit.

RESULTS

One thousand and one hundred seventy-four patients were studied (481 patients with IGE, 402 people with TLE, and 291 persons with FS). While the groups differed in their demographic and clinical characteristics, the rates of ictal injury did not differ significantly between the groups. Tongue injury was more frequently reported by patients with TLE compared with that by people with IGE or FS. Other types/locations of ictal injury were more or less reported by all three groups of the patients.

CONCLUSION

Ictal injuries may happen with more or less similar rates among people with epilepsy (IGE and TLE) and those with FS. Ictal injury (rate, type, or location) should not be used as a marker for any specific diagnosis among people with seizures.

Evaluation of potential auras in generalized epilepsy from EEG signals using deep convolutional neural networks and time-frequency representation

The general uncertainty of epilepsy and its unpredictable seizures often affect badly the quality of life of people exposed to this disease. There are patients who can be considered fortunate in terms of prediction of any seizures. These are patients with epileptic auras. In this study, it was aimed to evaluate pre-seizure warning symptoms of the electroencephalography (EEG) signals by a convolutional neural network (CNN) inspired by the epileptic auras defined in the medical field. In this context, one-dimensional EEG signals were transformed into a spectrogram display form in the frequency-time domain by applying a short-time Fourier transform (STFT). Systemic changes in pre-epileptic seizure have been described by applying the CNN approach to the EEG signals represented in the image form, and the subjective EEG-Aura process has been tried to be determined for each patient. Considering all patients included in the evaluation, it was determined that the 1-min interval covering the time from the second minute to the third minute before the seizure had the highest mean and the lowest variance to determine the systematic changes before the seizure. Thus, the highest performing process is described as EEG-Aura. The average success for the EEG-Aura process was 90.38 ± 6.28%, 89.78 ± 8.34% and 90.47 ± 5.95% for accuracy, specificity and sensitivity, respectively. Through the proposed model, epilepsy patients who do not respond to medical treatment methods are expected to maintain their lives in a more comfortable and integrated way.

Clinical Analysis of Partial Epilepsy with Auras

Background:

An aura is usually considered to be the initial clinical sign of a seizure. The types of abnormal neuron activities (i.e., localized and generalized firing) play an important role in the diagnosis of epilepsy. The goal of this study was to investigate the types of auras and its correlation with the localization and treatment of epilepsy.

Methods:

The 426 epileptic patients with auras from a single center were reviewed with reference to International League Against Epilepsy (ILAE, 1981) classification; the clinical manifestations and incidence of auras were analyzed in this retrospective study, as well as the results of electroencephalogram (EEG), brain magnetic resonance imaging (MRI) and the treatment methods.

Results:

Among the 426 epileptic patients, six different types of auras were defined, including autonomic auras, sensory auras, mental and affective auras, aura as vertigo, cognitive auras, and unspeakable feelings. Duration of auras ranged from 2 s to 7 min; the median duration of auras was 64.2 s. Abnormal EEG was observed in 297 (69.72%) patients. Moreover, abnormal brain MRI was observed in 125 (29.34%) patients. Nineteen (4.46%) epilepsy patients with auras underwent both surgeries and antiepileptic drugs (AEDs) while others were treated only with AEDs.

Conclusions:

This study suggested that auras played an important role in the diagnosis, classification, and localization of epilepsy. Epileptic aura could help differentiate partial seizure from generalized seizure.

On the nose: Olfactory disturbances in patients with transient epileptic amnesia

OBJECTIVE

While olfactory hallucinations are relatively rare in epilepsy, a high prevalence (up to 42%) has been reported in one form - Transient Epileptic Amnesia (TEA). TEA is characterized by recurring amnestic seizures and is commonly associated with persistent interictal memory deficits. Despite reports of changes in smell, olfactory ability has not been objectively assessed in this group. The aim of this study was to measure olfactory ability in patients with TEA and explore whether olfactory symptoms relate to other clinical variables.

METHODS

Fifty-five participants with TEA were recruited from The Impairment of Memory in Epilepsy project database. The presence of olfactory symptoms was obtained via case notes and clinical interview. Participants completed questionnaires to evaluate their olfaction and memory function subjectively. Olfactory ability was measured using the University of Pennsylvania Smell Identification Test (UPSIT). TEA participants' performance was compared to 50 matched healthy control participants. A subset of TEA participants (n=26) also completed a battery of memory tests including standard neuropsychological measures, and assessment of accelerated long-term forgetting and autobiographical memory.

RESULTS

Olfactory hallucinations were reported in 55% of patients with TEA. A significant reduction in smell identification (UPSIT) was found between patients with TEA and healthy controls (p<0.001). Epilepsy variables, including history of olfactory hallucinations, were not predictive of olfactory ability. Patients reported ongoing memory difficulties and performed below normative values on objective tests. While no correlation was found between objective measures of memory and olfactory performance, subjective complaints of route finding difficulty was associated with UPSIT score.

CONCLUSIONS

Impairments in odor identification are common in patients with TEA and exceed changes that occur in normal aging. Olfactory hallucinations occurs in approximately half of patients with TEA, but do not always coincide with reduced sense of smell. Olfactory impairment and interictal memory problems both occur frequently in TEA but are not closely associated.

Focal interictal epileptiform discharges in idiopathic generalized epilepsy

Are idiopathic generalized epilepsies (IGEs) truly generalized? Do IGEs represent a continuum or rather distinct syndromes? Focal changes in the electroencephalography (EEG) have been reported in IGEs. The aim of this work is to investigate focal interictal epileptiform discharges (IEDs) in IGEs, and their relation to clinical variables. Forty-one IGE patients (classified according to ILAE, 2001) were recruited from a tertiary center (age 23 ± 10.938 years). Their files were reviewed and they were subjected to clinical examination and interictal EEG. Patients with focal IEDs were compared to those without focal IEDs. Nine patients had juvenile myoclonic epilepsy (JME) and 32 had idiopathic epilepsy with generalized tonic-clonic seizures only (EGTCSA). Focal IEDs were found in 20 patients, mostly in the frontal (45.5 %) and temporal (31.8 %) distribution. Patients with focal IEDs were treated with a larger number of combined antiepileptic drugs (AEDs) (p value = 0.022). No significant difference was found between the two groups regarding age, sex, age at onset, epilepsy syndrome, seizure frequency, family history, AEDs used (sodium valproate and carbamazepine) and their doses. Seventeen EGTCSA patients had focal IEDs. They were treated with larger number of combined AEDs (p value = 0.0142). No significant difference was found between the EGTCSA patients with and those without focal IEDs regarding age, sex, age at onset, seizure frequency, family history and AEDs doses. Caution must be applied in the interpretation of interictal focal IEDs. These focal changes may be related to prognosis, however this needs further investigation.

Auras in generalized epilepsy

OBJECTIVE

We studied the frequency of auras in generalized epilepsy (GE) using a detailed semistructured diagnostic interview.

METHODS

In this cross-sectional study, participants with GE were drawn from the Epilepsy Phenome/Genome Project (EPGP). Responses to the standardized diagnostic interview regarding tonic-clonic (grand mal) seizures were then examined. This questionnaire initially required participants to provide their own description of any subjective phenomena before their "grand mal seizures." Participants who provided answers to these questions were considered to have an aura. All participants were then systematically queried regarding a list of specific symptoms occurring before grand mal seizures, using structured (closed-ended) questions.

RESULTS

Seven hundred ninety-eight participants with GE were identified, of whom 530 reported grand mal seizures. Of these, 112 (21.3%) reported auras in response to the open-ended question. Analysis of responses to the closed-ended questions suggested that 341 participants (64.3%) experienced at least one form of aura.

CONCLUSIONS

Auras typically associated with focal epilepsy were reported by a substantial proportion of EPGP subjects with GE. This finding may support existing theories of cortical and subcortical generators of GE with variable spread patterns. Differences between responses to the open-ended question and closed-ended questions may also reflect clinically relevant variation in patient responses to history-taking and surveys. Open-ended questions may underestimate the prevalence of specific types of auras and may be in part responsible for the underrecognition of auras in GE. In addition, structured questions may influence participants, possibly leading to a greater representation of symptoms.