Panayiotopoulos syndrome: a consensus view

Scalp EEG-recorded high-frequency oscillations can predict seizure activity in Panayiotopoulos syndrome

OBJECTIVE

We studied the relationship between the clinical course of Panayiotopoulos syndrome (PS) and high-frequency oscillations (HFOs) captured during interictal scalp electroencephalography (EEG) to determine the feasibility of using HFOs to detect seizure activity in PS.

METHODS

We analyzed the interictal scalp EEGs of 18 children with PS. Age parameters, seizure frequencies, and antiepileptic drugs were compared between the HFO-positive (HFOPG) and HFO-negative (HFONG) groups.

RESULTS

Thirteen patients (72.2%) had HFOs while five patients (27.8%) had no HFOs in 194 interictal EEG records. We found no statistically significant differences in the mean age of epilepsy onset and last seizure, seizure frequency, or frequency of status epilepticus. However, the seizure activity period of the HFOPG was significantly longer than that of the HFONG. Patients with an HFO duration longer than 2 years were intractable to treatment. In most cases, seizures did not occur in the absence of HFOs, even when the spikes remained.

CONCLUSIONS

HFOs are related to the seizure activity period in patients with PS.

SIGNIFICANCE

We propose that HFOs are a biomarker of epileptogenicity and an indicator for drug reduction because seizures did not occur if HFOs disappeared even if the spikes remained.

A reappraisal of interictal EEG characteristics in self-limited epilepsy with autonomic seizures, formerly known as Panayiotopoulos syndrome or early-onset benign occipital epilepsy

PURPOSE

In the 2022 New International Classification of Epilepsy Syndromes, self-limited epilepsy with autonomic seizures (SeLEAS), formerly known as Panayiotopoulos syndrome is recognized as an electroclinical syndrome that is clinically characterized by autonomic seizures and electroencephalographically by multifocal EEG foci. EEG studies were reviewed herein and the suitability of the EEG definition to characterize SeLEAS was assessed.

METHODS AND RESULTS

The EEG findings of SeLEAS studies published to date were reviewed and typical sites of EEG foci and their evolutionary changes with age were analyzed. Although previous studies investigated the details of interictal EEG characteristics in a sufficient number of SeLEAS cases, there were few systematically analyzing cross sectional and longitudinal EEG changes except one study. Despite these limited evidence, I propose the following practical and useful EEG definition. The interictal EEG characteristics of SeLEAS are multifocal EEG foci with age-dependent predominant locations; occipital (O) at 2-5 years old, and occipital and frontopolar (synchronous and independent O and Fp spikes) at 4-7 years old and centro-parieto-temporal (CPT) at 6-10 years old. O EEG foci evolve to multifocal EEG foci with a O-Fp or CPT predominance with age and disappear by 12∼16 years old. O-Fp EEG foci may further evolve to generalized spike-wave complexes and rarely to spike-wave activated in sleep. In rare cases, the EEGs do not have epileptic EEG foci.

CONCLUSION

Interictal EEG foci in SeLAES may have different EEG patterns in terms of location and the mode of appearance depending on the age at which EEG is recorded. O-Fp EEG foci may be a specific EEG pattern indicating a diagnosis of SeLEAS.

Epilepsy in Children With Congenital Heart Disease: Risk Factors and Characteristic Presentations

BACKGROUND

Children with a congenital heart disease (CHD) are at a higher risk of developing epilepsy than the general population, but detailed characteristics of CHD-associated epilepsy have not been clarified. The purposes of this study were to determine the risk factors for developing epilepsy associated with CHD and to elucidate the characteristics of such epilepsy.

METHODS

We performed a retrospective cohort study based on medical records of pediatric patients with CHD who were born between January 2006 and December 2016, underwent cardiac surgery at Okayama University Hospital, and were followed up until at least age three years. Multivariate logistic regression analysis was used to determine factors particularly associated with epilepsy occurrence. In patients who developed epilepsy, clinical data on seizure characteristics were further investigated.

RESULTS

We collected data from 1024 patients, and 41 (4.0%) developed epilepsy. The presence of underlying disease (odds ratio [OR]: 2.413; 95% confidence interval [CI]: 1.150 to 4.883) and the Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery score category 2 (OR: 4.373; 95% CI: 1.090 to 29.150) and category 5 (OR: 10.385; 95% CI: 1.717 to 89.016) were significantly related to epilepsy occurrence. Of the 41 patients with epilepsy, 15 (including nine with hypoplastic left heart syndrome) had focal impaired awareness seizures specified as autonomic seizures with vomiting, which tends to escape detection.

CONCLUSIONS

We clarified the risk factors for developing epilepsy in children with CHD. We also found that autonomic seizure with vomiting is an important symptom in these children.

A Case Report of a 5-Year-Old Girl with Self-Limited Epilepsy with Autonomic Seizures

BACKGROUND

Self-limited epilepsy with autonomic seizures (SeLEAS), formerly known as Panayiotopoulos syndrome (PS), is a common multifocal autonomic childhood epileptic syndrome. SeLEAS affects 6% of children in between the ages of 1 and 15 years who have had one or more afebrile seizures in their lifetime.

CASE

A 5-year-old girl was admitted to the paediatric emergency room (ER) of our hospital due to a reported episode of vomiting during her sleep, followed by central cyanosis perorally of sort duration (<5'), a right turn of her head, and gaze fixation with right eye deviation. She was dismissed after a one-day hospitalization free of symptoms. A month later, the patient was admitted to the paediatric ER of a tertiary health unit due to a similar episode. The patient underwent EEG, which revealed pathologic paroxysmal abnormalities of high-amplitude sharp waves and spike-wave complexes in temporal-occipital areas of the left hemisphere, followed by enhancement of focal abnormalities in temporal-occipital areas of the left hemisphere during sleep. The patient was diagnosed with SeLEAS and started levetiracetam.

CONCLUSIONS

SeLEAS can be easily misdiagnosed as many physicians may not be very familiar with this disease, and, on the other hand, the autonomic manifestations can be easily disregarded as seizures. The physician must always be alert and search beneath the symptoms to find the cause rather than only treat them.

Epilepsy syndromes in cerebral palsy: varied, evolving and mostly self-limited

Seizures occur in approximately one-third of children with cerebral palsy. This study aimed to determine epilepsy syndromes in children with seizures and cerebral palsy due to vascular injury, anticipating that this would inform treatment and prognosis. We studied a population-based cohort of children with cerebral palsy due to prenatal or perinatal vascular injuries, born 1999-2006. Each child's MRI was reviewed to characterize patterns of grey and white matter injury. Children with syndromic or likely genetic causes of cerebral palsy were excluded, given their inherent association with epilepsy and our aim to study a homogeneous cohort of classical cerebral palsy. Chart review, parent interview and EEGs were used to determine epilepsy syndromes and seizure outcomes. Of 256 children, 93 (36%) had one or more febrile or afebrile seizures beyond the neonatal period and 87 (34%) had epilepsy. Children with seizures were more likely to have had neonatal seizures, have spastic quadriplegic cerebral palsy and function within Gross Motor Function Classification System level IV or V. Fifty-six (60%) children with seizures had electroclinical features of a self-limited focal epilepsy of childhood; we diagnosed these children with a self-limited focal epilepsy-variant given the current International League Against Epilepsy classification precludes a diagnosis of self-limited focal epilepsy in children with a brain lesion. Other epilepsy syndromes were focal epilepsy-not otherwise specified in 28, infantile spasms syndrome in 11, Lennox-Gastaut syndrome in three, genetic generalized epilepsies in two and febrile seizures in nine. No epilepsy syndrome could be assigned in seven children with no EEG. Twenty-one changed syndrome classification during childhood. Self-limited focal epilepsy-variant usually manifested with a mix of autonomic and brachio-facial motor features, and occipital and/or centro-temporal spikes on EEG. Of those with self-limited focal epilepsy-variant, 42/56 (75%) had not had a seizure for >2 years. Favourable seizure outcomes were also seen in some children with infantile spasms syndrome and focal epilepsy-not otherwise specified. Of the 93 children with seizures, at last follow-up (mean age 15 years), 61/91 (67%) had not had a seizure in >2 years. Children with cerebral palsy and seizures can be assigned specific epilepsy syndrome diagnoses typically reserved for normally developing children, those syndromes commonly being age-dependent and self-limited. Compared to typically developing children with epilepsy, self-limited focal epilepsy-variant occurs much more commonly in children with cerebral palsy and epilepsy. These findings have important implications for treatment and prognosis of epilepsy in cerebral palsy, and research into pathogenesis of self-limited focal epilepsy.

Self-limited epilepsy with autonomic seizures: A case report

Self-limited epilepsy with autonomic seizures, formerly known as benign occipital epilepsy of childhood or Panayiotopoulos syndrome is a focal epilepsy that is part of the epileptic syndromes with onset during childhood. The objective of this report is to raise awareness about its importance and describe the clinical manifestations, timely diagnosis, and treatment. A pediatric patient admitted with gastrointestinal manifestations is presented. The autonomic manifestations must be considered as part of the clinical spectrum that includes this disease and the digestive and autonomic manifestations that mask the diagnosis, sometimes even in the absence of motor seizures themselves. Electroencephalographic confirmation was performed, avoiding cataloging it in other differential diagnoses.

Drug-resistant epilepsy at the age extremes: Disentangling the underlying etiology

The incidence of epilepsy is highest at the extreme age ranges: childhood and elderly age. The most common syndromes in these demographics - self-limited epilepsies of childhood and idiopathic generalized epilepsies in pediatric age, focal epilepsy with structural etiology in older people - are expected to be drug responsive. In this work, we focus on such epilepsy types, overviewing the complex clinical background of unexpected drug-resistance. For self-limited epilepsies of childhood and idiopathic generalized epilepsies, we illustrate drug-resistance resulting from syndrome misinterpretation, reason on possible unexpected courses of epilepsy, and explicate the influence of inappropriate treatments. For elderly-onset epilepsy, we show the challenges in differential diagnosis possibly leading to pseudoresistance and analyze how drug-resistant epilepsy can arise in stroke, neurocognitive disorders, brain tumors, and autoimmune encephalitis. In children and senior people, drug-resistance can be regarded as a hint to review the diagnosis or explore alternative therapeutic strategies. Refractory seizures are not only a therapeutic challenge, but also a cardinal sign not to be overlooked in syndromes commonly deemed to be drug-responsive.

International League Against Epilepsy classification and definition of epilepsy syndromes with onset in childhood: Position paper by the ILAE Task Force on Nosology and Definitions

The 2017 International League Against Epilepsy classification has defined a three-tier system with epilepsy syndrome identification at the third level. Although a syndrome cannot be determined in all children with epilepsy, identification of a specific syndrome provides guidance on management and prognosis. In this paper, we describe the childhood onset epilepsy syndromes, most of which have both mandatory seizure type(s) and interictal electroencephalographic (EEG) features. Based on the 2017 Classification of Seizures and Epilepsies, some syndrome names have been updated using terms directly describing the seizure semiology. Epilepsy syndromes beginning in childhood have been divided into three categories: (1) self-limited focal epilepsies, comprising four syndromes: self-limited epilepsy with centrotemporal spikes, self-limited epilepsy with autonomic seizures, childhood occipital visual epilepsy, and photosensitive occipital lobe epilepsy; (2) generalized epilepsies, comprising three syndromes: childhood absence epilepsy, epilepsy with myoclonic absence, and epilepsy with eyelid myoclonia; and (3) developmental and/or epileptic encephalopathies, comprising five syndromes: epilepsy with myoclonic-atonic seizures, Lennox-Gastaut syndrome, developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep, hemiconvulsion-hemiplegia-epilepsy syndrome, and febrile infection-related epilepsy syndrome. We define each, highlighting the mandatory seizure(s), EEG features, phenotypic variations, and findings from key investigations.

Genetic Epilepsy Syndromes

PURPOSE OF REVIEW

This article reviews the clinical features, typical EEG findings, treatment, prognosis, and underlying molecular etiologies of the more common genetic epilepsy syndromes. Genetic generalized epilepsy, self-limited focal epilepsy of childhood, self-limited neonatal and infantile epilepsy, select developmental and epileptic encephalopathies, progressive myoclonus epilepsies, sleep-related hypermotor epilepsy, photosensitive occipital lobe epilepsy, and focal epilepsy with auditory features are discussed. Also reviewed are two familial epilepsy syndromes: genetic epilepsy with febrile seizures plus and familial focal epilepsy with variable foci.

RECENT FINDINGS

Recent years have seen considerable advances in our understanding of the genetic factors underlying genetic epilepsy syndromes. New therapies are emerging for some of these conditions; in some cases, these precision medicine approaches may dramatically improve the prognosis.

SUMMARY

Many recognizable genetic epilepsy syndromes exist, the identification of which is a crucial skill for neurologists, particularly those who work with children. Proper diagnosis of the electroclinical syndrome allows for appropriate treatment choices and counseling regarding prognosis and possible comorbidities.

Panayiotopoulos syndrome: Unusual clinical manifestations

PURPOSE

We retrospectively analyzed the electroclinical features, treatment, and outcome of patients with Panayiotopoulos syndrome (PS) who presented with unusual clinical manifestations.

METHOD

A retrospective, descriptive, multicenter study was conducted evaluating 44 patients with PS who had seizures with an unusual semiology. Data from patients with PS seen at eight Argentine centers between April 2000 and April 2019 were collected.

RESULTS

Twelve patients (29.2%) had ictal syncope or syncope-like epileptic seizures. Three children (7.3%) had recurrent episodes of vomiting. Four patients (9.7%) presented with urinary incontinence associated with autonomic signs and consciousness impairment. One child had hiccups with autonomic manifestations followed by eye deviation. One boy had episodes of laughter with autonomic symptoms followed by loss of consciousness. Six patients (14.6%) had hyperthermia without acute febrile illness with autonomic symptoms as the first manifestation. Six others (14.6%) had focal motor seizures characterized by eye and head deviation in four and eyelid blinking in two. Four patients (9.7%) had ictal headache as the initial manifestation followed by nausea and vomiting. Two children (4.8%) had their first seizure while asleep associated with cardiorespiratory arrest. Two children (4.8%) had oral automatisms, such as sucking and chewing. In two children (4.8%) coughing was the initial manifestation followed by emetic symptoms. One patient (2.3%) had vertigo with a sensation of fear, with eye deviation and unresponsiveness. One child started with continuous spikes and waves during slow sleep, behavior disturbances, and emetic symptoms.

CONCLUSION

In this study, evidence of the existence of unusual clinical cases of PS with typical EEG patterns was found. Outcome was excellent.

Neuropsychological and behavioral profiles of self-limited epileptic syndromes of childhood: a cross-syndrome comparison

Childhood epilepsy with centro-temporal spikes (CECTS), Childhood absence epilepsy (CAE) and Panayiotopoulos syndrome (PS) are some of the most common pediatric epileptic syndromes. Despite the relatively benign (self-limited) course of epilepsy, current evidence suggests that these conditions are associated with an increased risk of neuropsychological and behavioral comorbidities. This study provides a cross-epileptic syndromes' comparison reporting on the cognitive and behavioral profile of a cohort of 32 children with CECTS (n = 14), CAE (n = 10) and PS (n = 8), aged 6 to 15 years old. Frequent, although often subclinical cognitive difficulties involving attention, executive functions and academic abilities were found in children with CECTS and CAE, and to a lesser extent in PS. Internalizing symptoms (particularly anxiety) were more common in the PS group compared to CECTS and CAE based on parental reports. Correlational analysis revealed a significant correlation between phonemic fluency and seizure-free interval at the time of evaluation, suggesting a beneficial effect of epilepsy remission on this executive function measure in all the three groups. These results add to existing literature providing further detail on neuropsychological and behavioral peculiarities of children with CECTS, CAE, and PS. Moreover, the need for neuropsychological assessment as part of the standard childhood epilepsy evaluation is stressed. The results are discussed in the context of the current literature, highlighting areas of consensus and controversies related to the clinical management of these epileptic syndromes as well as directions for future research.

Probability of Remission of the Main Epileptic Syndromes in Childhood

AIM

To determine the long-term probability of remission without antiepileptic treatment of common epileptic syndromes and of children without a specific syndromic diagnosis.

PATIENTS AND METHODS

All children less than 14 years old with 2 or more unprovoked seizures seen at our hospital between June 1, 1994, and March 1, 2011 (n = 680), were included and prospectively followed up until August 15, 2020. Syndromic diagnosis was made retrospectively but blinded to subsequent evolution, employing the data available at 6 months after diagnosis and under predefined operational criteria.

RESULTS

The Kaplan-Meier estimate of the probability of achieving a remission period of at least 5 years, with neither seizures nor antiepileptic treatment at 14 years was 97% for well-defined childhood epilepsy with centrotemporal spikes, 82% for uncertain childhood epilepsy with centrotemporal spikes, 85% for well-defined Panayiotopoulos syndrome, 88% for uncertain Panayiotopoulos syndrome, 93% for nonfamilial self-limited infantile epilepsy, 100% for familial self-limited infantile epilepsy, 86% for absence epilepsy, 6% for juvenile myoclonic epilepsy, 71% for cryptogenic West syndrome, 72% for patients with no associated neurologic deficits and no specific syndromic diagnosis, 65% for symptomatic West syndrome, and 40% for patients with associated neurologic deficits and no specific syndromic diagnosis.

CONCLUSIONS

The study results highlight the long-term outcomes of the main epileptic syndromes and also of the patients with no syndromic diagnosis.

Epilepsy: Epileptic Syndromes and Treatment

Epilepsy can now be diagnosed even in the presence of one unprovoked seizure or if the diagnosis of an epilepsy syndrome can be made. Epilepsy syndromes represent a specific set of seizure types and electroencephalographic and imaging features that tend to have age-dependent features, triggers, and prognosis. Epilepsy syndromes are the third and final level of epilepsy diagnosis, after classification of seizure and epilepsy types. Some epilepsy syndromes are self-limiting and pharmacoresponsive and others are pharmacoresistant and associated with poor developmental outcomes (epileptic and developmental encephalopathy). Features and management of 7 common age-dependent pediatric epilepsy syndromes are described.

Recognition of interictal and ictal discharges on EEG. Focal vs generalized epilepsy

INTRODUCTION

The differentiation between focal and generalized epilepsies based on clinical and electroencephalographic features is difficult and sometimes confusing.

OBJECTIVE

To review the EEG findings in patients with focal epilepsy.

METHODS

An extensive literature review was done. We used the following Pubmed and Medline descriptors alone and in different combinations for database searching: focal, partial, epilepsy, electroencephalographic findings, and EEG. Additional filters included review, original articles, and language limited to Spanish and English. Using the above criteria, a total of 69 articles showed the interictal and ictal EEG findings in focal epilepsy.

DEVELOPMENT

Focal epileptiform discharges and persistence of focal abnormalities, characterize the interictal EEG findings in focal epilepsies. To distinguish SBS from primary generalized spike waves are required to note: (a) a lead-in time of at least 2 s, (b) the morphology of the focal triggering spikes clearly differ from that of the bisynchronous epileptiform paroxysms, and (c) the morphology of triggering spikes resemble that of other focal spikes from the same region. Focal and Generalized Epilepsy can coexist. Delayed Lateralization on EEG with inconclusive onset and bizarre semiology confusing semiology should not be confused with generalized onset seizures with focal evolution.

CONCLUSIONS

A close attention to localization and morphology of epileptiform discharges, the correct interpretation of secondary bilateral synchrony, and provocative maneuvers help to correctly identify the EEG findings leading to diagnose focal epilepsies. The presence of generalized epileptiform activity does not rule out the existence of a focal epilepsy.

Case Report: Four Cases of Panayiotopoulos Syndrome Evolving to Juvenile Myoclonic Epilepsy

Panayiotopoulos syndrome (PS) is a self-limited focal epilepsy appearing in childhood. Seizures in PS are self-limiting and do not usually continue into adulthood. Juvenile myoclonic epilepsy (JME) is the most common type of idiopathic generalized epilepsy, developing around puberty and continuing throughout adulthood. We describe four cases of PS in childhood in which JME developed in adolescence. Age at onset ranged from 4 to 8 years for PS, and 11 to 14 years for JME. JME developed after PS subsided, with the interval between last PS seizure and first JME seizure ranging from 1 to 10 years. No link between the two conditions has previously been described. Since PS is considered to show good prognosis and to be self-limiting, long-term observation has been considered unnecessary. No definitive factors were found to predict future evolution to JME in our series, so longer-term follow-up may be warranted for all PS patients.

Sleep and Epilepsy Link by Plasticity

We aimed to explore the link between NREM sleep and epilepsy. Based on human and experimental data we propose that a sleep-related epileptic transformation of normal neurological networks underlies epileptogenesis. Major childhood epilepsies as medial temporal lobe epilepsy (MTLE), absence epilepsy (AE) and human perisylvian network (PN) epilepsies - made us good models to study. These conditions come from an epileptic transformation of the affected functional systems. This approach allows a system-based taxonomy instead of the outworn generalized-focal classification. MTLE links to the memory-system, where epileptic transformation results in a switch of normal sharp wave-ripples to epileptic spikes and pathological high frequency oscillations, compromising sleep-related memory consolidation. Absence epilepsy (AE) and juvenile myoclonic epilepsy (JME) belong to the corticothalamic system. The burst-firing mode of NREM sleep normally producing sleep-spindles turns to an epileptic working mode ejecting bilateral synchronous spike-waves. There seems to be a progressive transition from AE to JME. Shared absences and similar bilateral synchronous discharges show the belonging of the two conditions, while the continuous age windows - AE affecting schoolchildren, JME the adolescents - and the increased excitability in JME compared to AE supports the notion of progression. In perisylvian network epilepsies - idiopathic focal childhood epilepsies and electrical status epilepticus in sleep including Landau-Kleffner syndrome - centrotemporal spikes turn epileptic, with the potential to cause cognitive impairment. Postinjury epilepsies modeled by the isolated cortex model highlight the shared way of epileptogenesis suggesting the derailment of NREM sleep-related homeostatic plasticity as a common step. NREM sleep provides templates for plasticity derailing to epileptic variants under proper conditions. This sleep-origin explains epileptiform discharges' link and similarity with NREM sleep slow oscillations, spindles and ripples. Normal synaptic plasticity erroneously overgrowing homeostatic processes may derail toward an epileptic working-mode manifesting the involved system's features. The impact of NREM sleep is unclear in epileptogenesis occurring in adolescence and adulthood, when plasticity is lower. The epileptic process interferes with homeostatic synaptic plasticity and may cause cognitive impairment. Its type and degree depends on the affected network's function. We hypothesize a vicious circle between sleep end epilepsy. The epileptic derailment of normal plasticity interferes with sleep cognitive functions. Sleep and epilepsy interconnect by the pathology of plasticity.

Neurocognitive and behavioural profile in Panayiotopoulos syndrome

AIM

To determine neurocognitive performance and behavioural problems in children with Panayiotopoulos syndrome.

METHOD

All 18 children (10 females, 8 males; mean age 4y 7mo; SD 1y 10mo) diagnosed with Panayiotopoulos syndrome at the Kempenhaeghe Epilepsy Center in the Netherlands between 2010 and 2017 were analysed retrospectively. All underwent a neuropsychological/behavioural assessment, an academic assessment, and a 24-hour electroencephalogram.

RESULTS

Mean full-scale IQ (93.5; range 76-123; p=0.04) and performance IQ (93.2; range 76-126; p=0.04) were within the normal range, although significantly lower compared to the normative mean. Verbal IQ (96.3; range 76-118) and processing speed (96.1; range 74-114) were not significantly lower. Simple auditory/visual reaction times, visual attention, visual-motor integration, and verbal memory were significantly lower compared to normative values. On average, patients with Panayiotopoulos syndrome were 8 months behind in arithmetic speed and 11 months behind in reading speed for the number of months in school. Behavioural questionnaires revealed significantly higher scores on reported internalizing behavioural problems.

INTERPRETATION

Children with Panayiotopoulos syndrome demonstrated diffuse cognitive dysfunction in full-scale IQ, performance IQ, visual attention, visual-motor integration, and verbal memory. A high incidence of internalizing behavioural problems was reported. This strongly suggests neuropsychological and behavioural comorbidity in children with Panayiotopoulos syndrome.

WHAT THIS PAPER ADDS

Children with Panayiotopoulos syndrome are at risk for cognitive deficits in various cognitive domains. Children with Panayiotopoulos syndrome are also prone to internalizing behavioural problems. Mild-to-severe academic underachievement was present in more than half of the children with Panayiotopoulos syndrome.

Panayiotopoulos syndrome and Gastaut syndrome are distinct entities in terms of neuropsychological findings

BACKGROUND

Although the courses of self-limited focal epilepsies of childhood are considered as benign, a handful of studies suggested that these children may suffer from cognitive problems. Implementing tailor-made educational strategies would aid these children to reach their full potentials. Therefore, it is crucial to understand and differentiate the complete neuropsychological and behavioral profiles of these rather common syndromes. We aimed to examine the distinct cognitive and behavioral profiles of the Panayiotopoulos syndrome (PS) and the Gastaut syndrome (GS), comparatively.

METHOD

Twenty patients with PS, 20 patients with GS, and 20 healthy controls have been recruited. The testing protocol included Wechsler Intelligence Scale for Children-Revised, Conner's Continuous Performance Test, Verbal Fluency Test, Stroop Color and Word Test, Color Trails Test, Tower of London Test, Symbol Digit Modalities Test, California Verbal Learning Test-Children's Version, Rey Complex Figure Test, Benton Face Recognition Test, Benton Judgment of Line Orientation, Peabody Picture Vocabulary Test, Reading and Writing Test, Child Behavior Checklist, Conner's Parent Rating Scale-48, and Behavior Rating Inventory of Executive Function. Demographical, clinical, electrophysiological data, and imaging findings have also been evaluated.

RESULTS

With regard to intelligence, the patients with PS scored less in all scales compared to the healthy controls. However, only the performance IQ (intelligence quotient) scores differed significantly between the patient groups, with the patients with PS scoring lower than the patients with GS. Verbal memory problems were eminent in both of the patient groups; whereas, visual memory was impaired only in the group with PS. Psychomotor speed was affected in both groups. Reading problems were prominent only in the patients with PS. Writing and arithmetic skills were defective in both patient groups. There were no noteworthy behavioral problems in comparison to healthy subjects.

CONCLUSION

Using neuropsychological profiles, this study demonstrated that the GS and the PS are two distinct entities. Cognitive dysfunction is a more prominent and widespread feature of the patients with PS; whereas, the patients with GS suffer only from milder and isolated cognitive problems.

No prevention or cure of epilepsy as yet

Approximately 20% of all epilepsy is caused by acute acquired injury such as traumatic brain injury, stroke and CNS infection. The known onset of the injury which triggers the epileptogenic process, early presentation to medical care, and a latency between the injury and the development of clinical epilepsy present an opportunity to intervene with treatment to prevent epilepsy. No such treatment exists and yet there has been remarkably little clinical research during the last 20 years to try to develop such treatment. We review possible reasons for this, possible ways to rectify the situations and note some of the ways currently under way to do so. Resective surgical treatment can achieve "cure" in some patients but is sparsely utilized. In certain "self-limiting" syndromes of childhood and adolescence epilepsy remits spontaneously. In a proportion of patients who become seizure free on medications or with dietary treatment, seizure freedom persists when treatment is discontinued. We discuss these situations which can be considered "cures"; and note that at present we have little understanding of mechanism of such cures, and cannot therefore translate them into a treatment paradigm targeting a "cure" of epilepsy. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.

Misdiagnosis and pitfalls in Panayiotopoulos syndrome

Panayiotopoulos syndrome (PS) is a frequent (6% among children of 1-15 years) and benign epileptic syndrome, characterized by predominantly autonomic symptoms (emesis, pallor, flushing, cyanosis, mydriasis/miosis, cardiorespiratory and thermoregulatory alterations, incontinence of urine and/or feces, hypersalivation, and modifications of intestinal motility) associated with simple motor focal seizures, which can be followed by secondary generalization. Panayiotopoulos syndrome can be extremely insidious, because it can mimic several condition, such as gastroenteritis, gastroesophageal reflux disease, encephalitis, syncope, migraine, sleep disorders, or even metabolic diseases. This peculiar pleiotropism should be kept in mind by child neurologists and pediatricians and general practitioners, because a wrong diagnosis may lead to inappropriate interventions. The consequences are high morbidity, costly mismanagement, and stress for children and their parents. The availability of electroencephalography (EEG) recording in pediatric Emergency Departments might be useful for a prompt and not-cost-consuming diagnosis. On the other hand, it is important to be aware of the possible, multifaceted, clinical presentations of PS and its clinical, radiological, and neurophysiological features in order to improve both recognition and management.

Epilepsy as a derailment of sleep plastic functions may cause chronic cognitive impairment - A theoretical review

We report on a peculiar way of chronic cognitive impairment associated with interictal epileptic activity during NREM sleep. We review three major groups of epilepsy: mesiotemporal epilepsy (MTLE) involving the epileptic derailment of the hippocampal declarative memory system; childhood developmental epileptic encephalopathies; and the spectrum disorders of the perisylvian communication network with the centrotemporal spike phenomenon, overarching child- and adulthood epilepsies, totaling up the majority of epilepsies in childhood. We outline high impact research-lines on the cognitive harm of epilepsy; causing specific or global cognitive decline through its interference with sleep plastic functions. We highlight the key role of interictal activity in the development of cognitive impairment and the fact that we are unarmed against this harm, antiepileptic pharmaco-therapy being ineffective against the interictal process marked by spikes and high frequency oscillations.

Sleep Related Epilepsy and Pharmacotherapy: An Insight

In the last several decades, sleep-related epilepsy has drawn considerable attention among epileptologists and neuroscientists in the interest of new paradigms of the disease etiology, pathogenesis and management. Sleep-related epilepsy is nocturnal seizures that manifest solely during the sleep state. Sleep comprises two distinct stages i.e., non-rapid eye movement (NREM) and rapid eye movement (REM) that alternate every 90 min with NREM preceding REM. Current findings indicate that the sleep-related epilepsy manifests predominantly during the synchronized stages of sleep; NREM over REM stage. Sleep related hypermotor epilepsy (SHE), benign partial epilepsy with centrotemporal spikes or benign rolandic epilepsy (BECTS), and Panayiotopoulos Syndrome (PS) are three of the most frequently implicated epilepsies occurring during the sleep state. Although some familial types are described, others are seemingly sporadic occurrences. In the present review, we aim to discuss the predominance of sleep-related epilepsy during NREM, established familial links to the pathogenesis of SHE, BECTS and PS, and highlight the present available pharmacotherapy options.

Panayiotopoulos syndrome and benign partial epilepsy with centro-temporal spikes: A comparative incidence study

PURPOSE

To compare the de novo incidence of Panayiotopoulos syndrome (PS, early-onset childhood occipital epilepsy) and a common epilepsy syndrome, benign epilepsy with centro-temporal spikes (BECTS), in children and young people.

METHODS

The incidence of PS and BECTS was recorded over 16 months in a population of children and young people (aged <16 years) living within a specific geographic area and epilepsy network within the North West of England and North Wales and the catchment area of the tertiary paediatric epilepsy centre. Monthly data collection proformas were circulated to the paediatricians and paediatric neurologists responsible for the evaluation of epilepsy in children within this area. This also included monthly reminders of the electro-clinical criteria for these syndromes. EEGs were undertaken in the neurophysiology department of the tertiary paediatric epilepsy centre. The departmental EEG database on all <16 year olds that underwent an EEG during the study period was examined to identify additional patients that may not have been reported via a proforma-reporting system.

RESULTS

The incidence of PS and BECTS was found to be 0.8 and 6.1 per 100,000 <16 year olds, respectively. The ages at seizure onset and diagnosis were similar for BECTS and PS.

CONCLUSION

This study is the first to determine a comparative incidence of PS and BECTS. The findings suggest BECTS is eight times more common than PS and that the incidence of PS is lower than previously suggested.

Occipito-Frontal Sharp Waves-An Under-Recognized Electroencephalogram Pattern in Self-Limited Idiopathic Childhood Focal Epilepsy

We report four children who highlight the potentially under-recognized electroencephalogram pattern of bilaterally synchronous occipito-frontal sharp waves, which may occur in children with Panayiotopoulos type self-limited childhood epilepsy but may be easily confused with the patterns of symptomatic generalized epilepsy. Our patients were young, healthy children who had infrequent, predominantly nocturnal, fairly prolonged seizures characterized by altered consciousness, vomiting, and autonomic features, or in one case nocturnal secondary generalized tonic-clonic convulsion. Their electroencephalograms showed stereotyped abundant sleep-activated sharp waves with maximum negativity in bilateral occipital and frontal greater than centro-temporo-parietal regions. On a "double-banana" bipolar montage, the sharp waves had upward deflections in frontal electrodes, downward deflections at occipital electrodes, and a positive phase reversal in the middle of each chain. The lower-amplitude occipital discharges slightly preceded the frontal discharges, consistent with posterior-to-anterior propagation likely originating from mesial occipital regions. In the proper clinical context, recognizing the electroencephalogram pattern of bilateral occipito-frontal sharp waves affords confidence in a favorable prognosis, presents the option to possibly defer daily treatment with antiepileptic medication, and shifts the emphasis to rescue medication for isolated seizures.

Panayiotopoulos Syndrome with a special emphasis of ictal semiologic features

PURPOSE

The aim was to identify the demographic, electroencephalographic findings, clinical features, especially ictal semiological symptoms of patients diagnosed with Panayiotopoulos Syndrome.

METHOD

The semiologic and EEG findings of 42 patients were reviewed. Statistical analysis was used to determine the frequencies of semiologic features and to define the symptom clusters.

RESULTS

The most common clinical features were nausea (54.8%), vomiting (50.0%), pallor (50.0%), deviation of head and eyes (45.2%), generalized seizures (35.7%), ictal syncope (33.3%) and stomach ache (26.2%). Visual manifestations which were observed in 38.9% of the patients were amaurosis, flashes of colourful lights, flashes of brightful lights, visual hallucinations and blurring of vision. Autonomic status epilepticus was observed in 21.4% of the patients. Cluster analysis of 13 most common symptoms showed a tendency toward 3 clusters. Pallor constituted a subgroup on its own whereas nausea, vomiting, deviation of head and eyes tended to occur together in the second subgroup and the third subgroup included semiologic features some of which were atypical for PS.

CONCLUSIONS

A broad spectrum of typical and atypical clinical features might be observed in patients with PS. Some of the semiologic features of PS might have tendency to occur together. Overlapping of typical autonomic features with some of the atypical features might suggest that PS, RE and ICOE-G were the constituents of the same neurobiological spectrum. Our detailed data might contribute to the awareness of a wide range of variabilites in the electroclinical features of PS.

A study on spike focus dependence of high-frequency activity in idiopathic focal epilepsy in childhood

Objective

Spike foci in benign epilepsy with centrotemporal spikes (BECTS) are related to seizure semiologies, but this relationship is inconspicuous in Panayiotopoulos syndrome (PS). We analyzed spike‐associated high‐frequency activity (HFA) and its relationship to spike foci in the electroencephalograms (EEGs) of patients with BECTS and PS in order to elucidate the pathophysiology of these epileptic syndromes.

Methods

In 35 patients with BECTS and 29 with PS, focal spikes in scalp sleep EEGs were first classified by clustering according to their characteristics, including shape and distribution. For each patient, three or fewer spike clusters were investigated by time‐frequency spectral analysis and single‐dipole analysis using a realistic three‐dimensional head model to explore the relationships between the presence or absence of spike‐associated HFA and the distribution of estimated spike sources.

Results

A total of 159 spike clusters were analyzed (96 in BECTS and 63 in PS). HFA was detected in 73 spike clusters (76.0%) in BECTS and 37 (58.7%) in PS, with a significant difference in the proportion of spike clusters with HFA (p = 0.024 by Fisher's exact test). In BECTS, spikes had relatively uniform distributions, but the proportion of spikes with associated HFA was significantly higher in the spike group with dipoles in the perirolandic areas (42 of 49) than in that with dipoles outside of the perirolandic areas (23 of 36; p = 0.037). In PS, The proportion of spikes with associated HFA was significantly higher in the spike group with dipoles in the occipital lobes (20 of 26) than in that with dipoles outside of the occipital lobes (13 of 33; p = 0.020).

Significance

The proportion of spike‐associated HFA was higher in BECTS than in PS. Particular pathophysiological meaning was indicated in spikes with dipoles in the perirolandic areas in BECTS and in spikes with dipoles in the occipital lobes in PS owing to the high proportions of spike‐associated HFA in these areas.

Long-Term Clinical and Electroencephalography (EEG) Consequences of Idiopathic Partial Epilepsies

Background

Idiopathic partial epilepsies of childhood (IPE) affect a considerable proportion of children. Three main electroclinical syndromes of IPE are the Benign Childhood Epilepsy with Centro-temporal Spikes (BECTS), Panayiotopoulos Syndrome (PS), and Childhood Epilepsy with Occipital Paroxysms (CEOP). In this study we investigated the long-term prognosis of patients with IPE and discussed the semiological and electroencephalography (EEG) data in terms of syndromic characteristics.

Material/Methods

This study included a group of consecutive patients with IPE who had been followed since 1990. Demographic and clinical variables were investigated. Patients were divided into 3 groups – A: Cases suitable for a single IPE (BECTS, PS and CEOP); B: cases with intermediate characteristics within IPEs; and C: cases with both IPE and IGE characteristics. Long-term data regarding the individual seizure types and EEG findings were re-evaluated.

Results

A total of 61 patients were included in the study. Mean follow-up duration was 7.8±4.50 years. The mean age at onset of seizures was 7.7 years. There were 40 patients in group A 40, 14 in group B, and 7 in group C. Seizure and EEG characteristics were also explored independently from the syndromic approach. Incidence of autonomic seizures is considerably high at 2–5 years and incidence of oromotor seizures is high at age 9–11 years. The EEG is most abnormal at 6–8 years. The vast majority (86%) of epileptic activity (EA) with parietooccipital is present at 2–5 years, whereas EA with fronto-temporal or multiple sites become more abundant between ages 6 and 11.

Conclusions

Results of the present study provide support for the age-related characteristics of the seizures and EEGs in IPE syndromes. Acknowledgement of those phenomena may improve the management of IPEs and give a better estimate of the future consequences.

Epidemiology of epilepsy

Epilepsy is a burden affecting no fewer than 50 million patients worldwide. It is a heterogeneous group of disorders comprising both common and very rare forms, thus rendering its epidemiological investigations rather difficult. Moreover, making an epilepsy diagnosis per se can be challenging due to an evolving system of classification, and its dependency on local habits and culture. Any attempt at meta-analyses must consider such biases when pooling data from different centers and countries. Differentiating a contextual seizure from chronic epilepsy is every epileptologist's daily mission, yet it is also crucial for achieving a proper estimation of the epidemiology of epilepsy. Our present objective was to provide an overview of the epidemiology of both syndromic and non-syndromic epilepsy. Most epileptic syndromes tend to be rare and, thus, the feasibility of epidemiological quantification in populations is also addressed. Regarding its prevalence and cost, epilepsy deserves greater attention than it generally receives, as it appears to continue to be a condition under persistent taboos.

Coexistence of fixation-off sensitivity and inverted fixation-off sensitivity in a female child with Panayiotopoulos syndrome: Video-electroencephalography documentation

Fixation-off sensitivity (FOS) is a rare phenomenon elicited by elimination of central vision and fixation, which even in the presence of light induces occipital paroxysms or generalized paroxysmal discharges. It is most commonly encountered in patients with idiopathic childhood occipital epilepsies but may also be observed in cases of symptomatic focal and generalized epilepsies. We describe a female Emirati child with Panayiotopoulos syndrome who exhibited FOS in addition to the reverse phenomenon called "inverted fixation-off sensitivity," in which the electroencephalographic discharges were suppressed by the absence of central vision or fixation and activated by central vision or fixation.

Panayiotopoulos syndrome presenting with respiratory arrest: A case report and literature review

We describe a child with Panayiotopoulos syndrome (PS) who presented with autonomic status epilepticus and developed respiratory arrest requiring intubation and mechanical ventilation. Because of that life-threatening episode and the risk of developing a similar event in subsequent seizures, we decided to initiate our patient on AED treatment. Such life-threatening complications were previously reported in only four children with PS. Although PS is considered to be a benign childhood epilepsy syndrome usually not requiring treatment with antiepileptic drugs, our case and the small number of similar cases in the literature show it is important to realize that it can rarely be associated with life-threatening complications. It is our opinion that children with PS who develop an episode of autonomic status epilepticus and those living in remote areas with no quick access to emergency departments should be initiated on AED therapy to minimize the risk of experiencing a subsequent potentially fatal seizure. We further suggest that the use of benzodiazepines in this syndrome should only be administered during the early stage of the seizure, since administration of this class of drugs during an established autonomic status epilepticus can result in further respiratory depression.

Antiepileptic drug treatment of rolandic epilepsy and Panayiotopoulos syndrome: clinical practice survey and clinical trial feasibility

BACKGROUND

The evidence base for management of childhood epilepsy is poor, especially for the most common specific syndromes such as rolandic epilepsy (RE) and Panayiotopoulos syndrome (PS). Considerable international variation in management and controversy about non-treatment indicate the need for high quality randomised controlled trials (RCT). The aim of this study is, therefore, to describe current UK practice and explore the feasibility of different RCT designs for RE and PS.

METHODS

We conducted an online survey of 590 UK paediatricians who treat epilepsy. Thirty-two questions covered annual caseload, investigation and management practice, factors influencing treatment, antiepileptic drug preferences and hypothetical trial design preferences.

RESULTS

132 responded (22%): 81% were paediatricians and 95% at consultant seniority. We estimated, annually, 751 new RE cases and 233 PS cases. Electroencephalography (EEG) is requested at least half the time in approximately 70% of cases; MRI brain at least half the time in 40%-65% cases and neuropsychological evaluation in 7%-8%. Clinicians reported non-treatment in 40%: main reasons were low frequency of seizures and parent/child preferences. Carbamazepine is the preferred older, and levetiracetam the preferred newer, RCT arm. Approximately one-half considered active and placebo designs acceptable, choosing seizures as primary and cognitive/behavioural measures as secondary outcomes.

CONCLUSIONS

Management among respondents is broadly in line with national guidance, although with possible overuse of brain imaging and underuse of EEG and neuropsychological assessments. A large proportion of patients in the UK remains untreated, and clinicians seem amenable to a range of RCT designs, with carbamazepine and levetiracetam the preferred active drugs.

Gastroesophageal reflux disease vs. Panayiotopoulos syndrome: an underestimated misdiagnosis in pediatric age?

Autonomic signs and symptoms could be of epileptic or nonepileptic origin, and the differential diagnosis depends on a number of factors which include the nature of the autonomic manifestations themselves, the occurrence of other nonictal autonomic signs/symptoms, and the age of the patient. Here, we describe twelve children (aged from ten months to six years at the onset of the symptoms) with Panayiotopoulos syndrome misdiagnosed as gastroesophageal reflux disease. Gastroesophageal reflux disease and Panayiotopoulos syndrome may represent an underestimated diagnostic challenge. When the signs/symptoms occur mainly during sleep, a sleep EEG or, if available, a polysomnographic evaluation may be the most useful investigation to make a differential diagnosis between autonomic epileptic and nonepileptic disorders. An early detection can reduce both the high morbidity related to mismanagement and the high costs to the national health service related to the incorrect diagnostic and therapeutic approaches. To decide if antiseizure therapy is required, one should take into account both the frequency and severity of epileptic seizures and the tendency to have potentially lethal autonomic cardiorespiratory involvement. In conclusion, we would emphasize the need to make a differential diagnosis between gastroesophageal reflux disease and Panayiotopoulos syndrome in patients with "an unusual" late-onset picture of GERD and acid therapy-resistant gastroesophageal reflux, especially if associated with other autonomic symptoms and signs.

Panayiotopoulos syndrome: a case series from Turkey

The aim of the study was to evaluate the demographic, clinical, and EEG characteristics of patients with Panayiotopoulos syndrome (PS) and the course of their illness. Thirty-eight patients followed up with a diagnosis of PS between January 2011 and December 2013 were evaluated. We found high rates of personal history of febrile convulsions, breath-holding spells, and family history of febrile convulsions, afebrile convulsion/epilepsy, migraine, and breath-holding spells. Seizures started before the age of eight in 87% of the patients, and the mean age at seizure onset was 4.6 years. Seizures were sleep-related in 81.5%, and autonomic status was seen in a third of the patients. The number of seizures was between 2 and 10 in 66% of the patients. The most common symptoms were ictus emeticus, eye/head deviation, and altered consciousness. Rolandic features were seen in 26% of the patients, and visual symptoms in 5%. Multifocal epileptiform discharges on EEG were identified in 84% of the patients. Two or more antiepileptic drugs were required in only 13% of the patients. Evolution to electrical status epilepticus in sleep and Gastaut-type epilepsy were seen in patients with more than ten seizures. The high rates of febrile convulsions, afebrile convulsions/epilepsy, migraine, and breath-holding spells in the patients and families suggest the importance of genetic factors and, perhaps, a common pathogenesis. However, the high rates of febrile convulsions and breath-holding spells in patients can be related to a misdiagnosis because of the similar symptoms. Despite its disturbing symptoms, PS is a benign epileptic syndrome requiring multiple antiepileptic drug use only in a small proportion of patients.

Modes of onset of epilepsy and differential diagnosis

Epilepsy has protean manifestations and may be diagnosed when two unprovoked seizures have occurred. This determination is nearly always based on the available history because most seizures have stopped long before patients arrive at medical care. Great care must be taken, even by experts, to correctly interpret the history and there is strong evidence that incorrect diagnoses are frequent. An abnormal EEG cannot rule epilepsy in or out unless an actual seizure is recorded. When the diagnosis of epilepsy is based only on two seizures, the seizures are usually generalized tonic-clonic. Less "severe" seizure types usually occur multiple times before prompting a medical visit. Some patients present with what seems to be a first generalized tonic-clonic seizure but have a history of less severe attacks that have not brought them to medical attention - epilepsy can then be diagnosed. Others present with staring spells, episodes of confusion, body jerks, spasms, drops, loss of speech and social interactions and/or cognitive function, paroxysmal events during sleep, and febrile seizures. This chapter examines and considers the differential diagnoses for each of these modes of presentation. The consequences of a missed alternate diagnosis, such as cardiac arrhythmia, may be profound.

Ictal priapism as an autonomic manifestation of Panayiotopoulos syndrome

Panayiotopoulos syndrome is an idiopathic epilepsy syndrome presenting with a large variety of autonomic symptoms. The mechanism of autonomic symptoms is still not well understood. A neurologically normal 13-month-old boy presented on 2 occasions with complex partial status epilepticus that included significant ictal priapism. Inpatient brain magnetic resonance imaging (MRI) scan showed restricted diffusion-weighted imaging within his left temporal lobe and electroencephalograms (EEGs) left temporal slowing only. An outpatient EEG 6 months later showed abundant multifocal, predominantly posterior, as well as irregular generalized spike-and-slow-wave discharges on normal background consistent with the diagnosis of Panayiotopoulos syndrome. Ictal priapism is a previously undescribed phenomenon that is consistent with parasympathetic manifestations noted in this young boy. Acute postictal MRI and EEG findings suggest that this undeniably fascinating seizure semiological sign may be localized to the left temporal region.

Occipital lobe seizures and epilepsies

Occipital lobe epilepsies (OLEs) manifest with occipital seizures from an epileptic focus within the occipital lobes. Ictal clinical symptoms are mainly visual and oculomotor. Elementary visual hallucinations are common and characteristic. Postictal headache occurs in more than half of patients (epilepsy-migraine sequence). Electroencephalography (EEG) is of significant diagnostic value, but certain limitations should be recognized. Occipital spikes and/or occipital paroxysms either spontaneous or photically induced are the main interictal EEG abnormalities in idiopathic OLE. However, occipital epileptiform abnormalities may also occur without clinical relationship to seizures particularly in children. In cryptogenic/symptomatic OLE, unilateral posterior EEG slowing is more common than occipital spikes. In neurosurgical series of symptomatic OLE, interictal EEG abnormalities are rarely strictly occipital. The most common localization is in the posterior temporal regions and less than one-fifth show occipital spikes. In photosensitive OLE, intermittent photic stimulation elicits (1) spikes/polyspikes confined in the occipital regions or (2) generalized spikes/polyspikes with posterior emphasis. In ictal EEG, a well-localized unifocal rhythmic ictal discharge during occipital seizures is infrequent. A bioccipital field spread to the temporal regions is common. Frequency, severity, and response to treatment vary considerably from good to intractable and progressive mainly depending on underlying causes.

Pediatric focal epilepsy syndromes

Benign epilepsy with centrotemporal spikes, early-onset childhood occipital epilepsy (Panayiotopoulos syndrome [PS]) and late-onset childhood occipital epilepsy (Gastaut type [LOCE-G]) are the principal pediatric focal epilepsy syndromes. They share major common characteristics: the appearance and resolution of electroclinical features are age related, there is a strong genetic predisposition, the clinical course is often mild with infrequent and easy to control seizures, interictal epileptiform activity is disproportionately abundant when compared with the clinical correlate, and tends to potentiate and generalize during sleep. In this review, we outline the relevant pathophysiology underlying this electroclinical spectrum. Then, the initial description of individual syndromes is followed by a summary of overlapping features and intermediate presentations that question the boundaries between these entities and provide the basis for the concept of a childhood seizure susceptibility syndrome. Additionally, we outline the main features of the related epileptic encephalopathies. An outlook on potential future lines of research completes this review.

Autonomic epileptic seizures, autonomic effects of seizures, and SUDEP

Many generalized tonic-clonic seizures are accompanied by profound autonomic changes. However, autonomic seizures and autonomic status epilepticus can also be seen with specific electroclinical syndromes (Panayiotopoulos syndrome), etiologies, and localizations. Such autonomic symptoms may impact cardiorespiratory function. While it is likely that several factors contribute to SUDEP, further study of both ictal respiratory and cardiac changes and underlying neuroanatomical mechanisms involved in autonomic seizure semiology are likely to provide important data to improve our understanding of the pathophysiology of this devastating condition. This paper will review the association between autonomic symptoms and epileptic seizures and will highlight the work of three young investigators. Drs. Lisa Bateman and Brian Moseley will review their work on cardiorespiratory effects of recorded seizures and how this assists in our understanding of SUDEP. Dr. John Millichap will review autonomic seizures and autonomic dysfunctions related to childhood epilepsy and will discuss the importance of expanded research efforts in this field.

Idiopathic focal epilepsies

In this chapter we include a series of epilepsies with onset in pediatric age characterized by focal seizures, idiopathic etiology, normal psychomotor development, and a benign course related to the spontaneous remission of seizures without sequelae. These entities are age-dependent and seizures tend to disappear spontaneously. For these reasons often the drug treatment is not necessary. On the basis of genetic assessment idiopathic focal epilepsies can be divided into two groups: nonautosomal dominant and autosomal dominant. In the group of nonautosomal entities we include benign epilepsy with centro-temporal spikes, Panayiotopoulos syndrome, idiopathic childhood occipital epilepsy described by Gastaut, and benign idiopathic midline spikes epilepsy. Seizures are rare, sometimes prolonged, as autonomic status in Panayiotopoulos syndrome. A common feature is the presence of peculiar EEG interictal paroxysmal abnormalities. In the group with an autosomal dominant mode of inheritance we include benign familial infantile seizures and benign familial neonatal-infantile seizures. These entities are characterized by partial seizures in cluster, self-limited in a brief period during the first months of life. There are no typical interictal EEG abnormalities. In some families a mutation in SCN2A, the gene coding for the 2α subunit of the voltage-gated sodium channel, has been described.

Benign childhood focal epilepsies

The idiopathic focal epilepsies comprise a group of syndromes characterized by focal-onset seizures for which there is no detectable structural brain abnormality and for which there is a proposed functional mechanism for the epilepsy and electroencephalography (EEG) abnormalities. This group includes benign rolandic epilepsy (BRE), benign epilepsy with occipital paroxysms (both early onset and late-onset types), idiopathic photosensitive occipital lobe epilepsy, and some less well-defined syndromes. The limits of the early onset idiopathic occipital epilepsy syndrome are not clear, and perhaps this entity represents part of a larger syndrome group of "autonomic" age-related epilepsies. The term "idiopathic" implies absence of a structural brain lesion and a genetic propensity to seizures. The term "benign" implies that the epileptic seizures are easily treated or require no treatment, show remission without sequelae with ultimate and definitive remission before adulthood, do not have severe or exceedingly disturbing seizures, and have no associated serious intellectual or behavioral disturbances. It may be that a syndrome is benign only when it can be recognized early with reasonable certainty, thereby avoiding unnecessary investigations, overtreatment, and lifestyle restrictions. Although BRE has such characteristic clinical and EEG features to make early recognition possible, this is less constantly so in the other focal idiopathic epilepsy syndromes, where the term "benign" may be inappropriate. Mild and selective neuropsychological impairment may occur even in those with typical syndromes but it is unclear whether such selective deficits outlast the active phase of epilepsy. Sometimes the clinical course may be complicated by obvious cognitive and language impairments. In such cases, the term benign is obviously inappropriate, even when seizures are rare. In most patients with the typical focal idiopathic epilepsy syndromes, medication is not necessary.

Signal change in hippocampus and current source of spikes in Panayiotopoulos syndrome

A 4-year-old girl with Panayiotopoulos syndrome presented with a history of 4 prolonged autonomic seizures. The clinical features of her seizures included, in order of occurrence, blank staring, pallor, vomiting, hemi-clonic movement on the right side, and unresponsiveness. A brain magnetic resonance imaging (MRI) showed a slightly high T₂ signal in the left hippocampus. Interictal electoencephalogram revealed spikes in the occipital area of the left hemisphere. We analyzed the current-source distribution of the spikes to examine the relationship between the current source and the high T₂ signal. The current source of the occipital spikes was not only distributed in the occipital area of both cerebral hemispheres, but also extended to the posterior temporal area of the left hemisphere. These findings suggest that the left temporal lobe may be one of the hyperexcitable areas and form part of the epileptogenic area in this patient. We hypothesized that the high T₂ signal in the left hippocampus of our patient may not have been an incidental lesion, but instead may be related to the underlying electroclinical diagnosis of Panayiotopoulos syndrome, and particularly seizure. This notion is important because an abnormal T₂ signal in the hippocampus may represent an acute stage of hippocampal injury, although there is no previous report of hippocampal pathology in Panayiotopoulos syndrome. Therefore, long-term observation and serial follow-up MRIs may be needed to confirm the clinical significance of the T₂ signal change in the hippocampus of this patient.