Childhood absence epilepsy: Behavioral, cognitive, and linguistic comorbidities

Early alterations of the neuronal network processing whisker-related sensory signal during absence epileptogenesis

OBJECTIVE

Epileptogenesis is the particular process during which the epileptic network builds up progressively before the onset of the first seizures. Whether physiological functions are impacted by this development of epilepsy remains unclear. To explore this question, we used Genetic Absence Epilepsy Rats From Strasbourg (GAERS), in which spike-and-wave discharges are initiated in the whisker primary somatosensory cortex (wS1) and first occur during cortical maturation. We studied the development of both the epileptic and the physiological wS1 circuits during cortical maturation to understand the interactions between them and the consequences for the animals' behavior.

METHODS

In sedated and immobilized rat pups, we recorded in vivo epileptic and whisker sensory evoked activities across the wS1 and thalamus using multicontact electrodes. We compared sensory evoked potentials based on current source density analysis. We then analyzed the multiunit activities evoked by whisker stimulation in GAERS and control rats. Finally, we evaluated behavioral performance dependent on the functionality of the wS1 cortex using the gap-crossing task.

RESULTS

We showed that the epileptic circuit changed during the epileptogenesis period in GAERS, by involving different cortical layers of wS1. Neuronal activities evoked by whisker stimulation were reduced in the wS1 cortex at P15 and P30 in GAERS but increased in the ventral posteromedial nucleus of the thalamus at P15 and in the posterior medial nucleus at P30, when compared to control rats. Finally, we observed lower performance in GAERS versus controls, at both P15 and P30, in a whisker-mediated behavioral task.

SIGNIFICANCE

Our data show that the functionality of wS1 cortex and thalamus is altered early during absence epileptogenesis in GAERS and then evolves before spike-and-wave discharges are fully expressed. They suggest that the development of the pathological circuit disturbs the physiological one and may be responsible for both the emergence of seizures and associated comorbidities.

Therapeutic Options for Childhood Absence Epilepsy

Childhood absence epilepsy (CAE) is a common pediatric generalized epileptic syndrome. Although it is traditionally considered as a benign self-limited condition, the apparent benign nature of this syndrome has been revaluated in recent years. This is mainly due to the increasing evidence that children with CAE can present invalidating neuropsychological comorbidities that will affect them up to adulthood. Moreover, a percentage of affected children can develop drug-resistant forms of CAE. The purpose of this review is to summarize the most recent studies and new concepts concerning CAE treatment, in particular concerning drug-resistant forms of CAE. A Pubmed search was undertaken to identify all articles concerning management and treatment of CAE, including articles written between 1979 and 2021. Traditional anticonvulsant therapy of CAE that is still in use is based on three antiepileptic drugs: ethosuximide which is the drug of choice, followed by valproic acid and lamotrigine. In the case of first line treatment failure, after two monotherapies it is usual to start a bi-therapy. In the case of absence seizures that are refractory to traditional treatment, other antiepileptic drugs may be introduced such as levetiracetam, topiramate and zonisamide.

Childhood absence epilepsy: Electro-clinical manifestations, treatment options, and outcome in a tertiary educational center

Purpose and Background

To evaluate the electro-clinical manifestations and outcomes of children with absence epilepsy at a tertiary center in Saudi Arabia.

Methods

This retrospective study reviewed the medical and EEG records of patients who were diagnosed to have CAE as per the International League Against Epilepsy (ILAE) definition for CAE. The study was conducted in the pediatric neurology clinic of King Khalid University Hospital, King Saud University Medical City, Riyadh, Saudi Arabia, between January 2000 and December 2019. Patients who did not meet (ILAE) criteria, lost follow-up, and those who did not receive treatment at KKUH were excluded. Data regarding the patient's disease, electro-clinical manifestations, anti-seizure medication response, and outcomes were collected.

Results

A total of 35 patients, with an average age at diagnosis of 7 ± 2.1 y, were included in the study; among them, 51.4% were female and approximately 48.6% presented with a family history of epilepsy. Regarding clinical features, all patients experienced staring and altered awareness, 94.2% had less than 20 spells per day at the time of diagnosis, and 65.7% were provoked by the hyperventilation test. Regarding EEG findings, all patients had bilateral, symmetrical, and synchronous discharges in the form of regular 3 Hz spike-and-wave complexes, and 94.3% had a generalized initial ictal discharge. Also, 22.8% had eye fluttering with electrographic seizures. Ethosuximide (ESM) was used as the drug of choice in 45.7% of the patients. Regarding clinical outcomes, 94.3% had their disease clinically controlled, and 80% had a normalized EEG after few months of starting anti-seizure medication. Finally, 37.2% experienced complete remission of epilepsy after 3–5 y; however, one patient developed juvenile myoclonic epilepsy.

Conclusion

This study described the electro-clinical manifestations of patients with childhood absence epilepsy and outcomes. Furthermore, early diagnosis and prompt treatment of childhood absence epilepsy improve treatment outcomes.

Alterations in white matter integrity and asymmetry in patients with benign childhood epilepsy with centrotemporal spikes and childhood absence epilepsy: An automated fiber quantification tractography study

PURPOSE

To investigate whether patients with benign childhood epilepsy with centrotemporal spikes (BECTS) and childhood absence epilepsy (CAE) show distinct patterns of white matter (WM) alterations and structural asymmetry compared with healthy controls and the relationship between WM alterations and epilepsy-related clinical variables.

METHODS

We used automated fiber quantification to create tract profiles of fractional anisotropy (FA) and mean diffusivity (MD) in twenty-six patients with BECTS, twenty-nine patients with CAE, and twenty-four healthy controls. Group differences in FA and MD were quantified at 100 equidistant nodes along the fiber tract and these alterations and epilepsy-related clinical variables were correlated. A lateralization index (LI) representing the structural asymmetry of the fiber tract was computed and compared between both patient groups and controls.

RESULTS

Compared with healthy controls, the BECTS group showed widespread FA reduction in 43.75% (7/16) and MD elevation in 50% (8/16) of identified fiber tracts, and the CAE group showed regional FA reduction in 31.25% (5/16) and MD elevation in 25% (4/16) of identified fiber tracts. In the BECTS group, FA and MD in the right anterior thalamic radiation positively and negatively correlated with the number of antiepileptic drugs, respectively, and MD in the right arcuate fasciculus (AF) positively correlated with seizure frequency. In the CAE group, the LI values were significantly lower in the inferior fronto-occipital fasciculus and the AF.

CONCLUSION

The two childhood epilepsy syndromes display different patterns of WM alterations and structural asymmetry, suggesting that neuroanatomical differences may underlie the different profiles of BECTS and CAE.

Functional reorganization of brain regions into a network in childhood absence epilepsy: A magnetoencephalography study

OBJECTIVE

Epilepsy is considered as a network disorder. However, it is unknown how normal brain activity develops into the highly synchronized discharging activity seen in disordered networks. This study aimed to explore the epilepsy brain network and the significant re-combined brain areas in childhood absence epilepsy (CAE).

METHODS

Twenty-two children with CAE were recruited to study the neural source activity during ictal-onset and interictal periods at frequency bands of 1-30 Hz and 30-80 Hz with magnetoencephalography (MEG) scanning. Accumulated source imaging (ASI) was used to analyze the locations of neural source activity and peak source strength.

RESULTS

Most of the participants had more active source activity locations in the ictal-onset period rather than in the interictal period, both at 1-30 Hz and 30-80 Hz. The frontal lobe (FL), the temporo-parietal junction (T-P), and the parietal lobe (PL) became the main active areas of source activity during the ictal period, while the precuneus (PC), cuneus, and thalamus were relatively inactive.

CONCLUSIONS

Some brain areas become more excited and have increased source activity during seizures. These significant brain regions might be re-combined to form an epilepsy network that regulates the process of absence seizures.

SIGNIFICANCE

The study confirmed that important brain regions are reorganized in an epilepsy network, which provides a basis for exploring the network mechanism of CAE development. Imaging findings may provide a reference for clinical characteristics.

Pretreatment Source Location and Functional Connectivity Network Correlated With Therapy Response in Childhood Absence Epilepsy: A Magnetoencephalography Study

Objective: This study aims to investigate the differences between antiepileptic drug (AED) responders and nonresponders among patients with childhood absence epilepsy (CAE) using magnetoencephalography (MEG) and to additionally evaluate whether the neuromagnetic signals of the brain neurons were correlated with the response to therapy.

Methods: Twenty-four drug-naïve patients were subjected to MEG under six frequency bandwidths during ictal periods. The source location and functional connectivity were analyzed using accumulated source imaging and correlation analysis, respectively. All patients were treated with appropriate AED, at least 1 year after their MEG recordings, their outcome was assessed, and they were consequently divided into responders and nonresponders.

Results: The source location of the nonresponders was mainly in the frontal cortex at a frequency range of 8–12 and 30–80 Hz, especially 8–12 Hz, while the source location of the nonresponders was mostly in the medial frontal cortex, which was chosen as the region of interest. The nonresponders showed strong positive local frontal connections and deficient anterior and posterior connections at 80–250 Hz.

Conclusion: The frontal cortex and especially the medial frontal cortex at α band might be relevant to AED-nonresponsive CAE patients. The local frontal positive epileptic network at 80–250 Hz in our study might further reveal underlying cerebral abnormalities even before treatment in CAE patients, which could cause them to be nonresponsive to AED. One single mechanism cannot explain AED resistance; the nonresponders may represent a subgroup of CAE who is refractory to several antiepileptic drugs.

Therapeutic approach to difficult-to-treat typical absences and related epilepsy syndromes

Introduction: typical absences (TAs), are brief, generalized epileptic seizures of abrupt onset and termination clinically manifesting with impairment of awareness and associated with 3 Hz spike-wave discharges on EEG. TAs may occur in different idiopathic generalized epilepsies (IGE). Despite treatment with adequate anti-seizure medications (ASMs), TAs may persist in ~25% of subjects. This narrative review focuses on the therapeutic approach to difficult-to-treat TAs occurring in the setting of IGE.Areas covered: a literature search was conducted on the topic of treatment of TAs.Expert opinion: ethosuximide (ESX), valproic acid (VPA) and lamotrigine (LTG), alone or in combination, are considered the first-choice drugs. In women of childbearing potential, VPA should be avoided. Alternative therapies (benzodiazepines, levetiracetam, topiramate, or zonisamide) should be considered in subjects unresponsive to monotherapy after the exclusion of pseudo-drug resistance. Newer ASMs such as brivaracetam and perampanel seem to be promising options. Well-conducted clinical trials aimed to evaluate the efficacy of alternative monotherapy (beyond ESX, VPA or LTG) or combination of ASMs on difficult-to-treat TAs, are warranted.

Group I metabotropic glutamate receptor-mediated long term depression is disrupted in the hippocampus of WAG/Rij rats modelling absence epilepsy

Absence epilepsy is frequently associated with cognitive dysfunction, although the underlying mechanisms are not well understood. Here we report that some forms of hippocampal synaptic plasticity are abnormal in symptomatic Wistar Albino Glaxo/Rijswijk (WAG/Rij) rats. Metabotropic Glu 1/5 receptor-mediated long term depression (LTD) at Schaffer collateral CA1 synapses is significantly reduced in symptomatic, 5-6 months old WAG/Rij rats compared to age-matched non epileptic control rats. There were no significant changes in mGlu1/5-dependent LTD in pre-symptomatic, 4-6 weeks old WAG/Rij rats compared to age matched controls. The changes in LTD found in symptomatic WAG/Rij forms are not indicative of general deficits in all forms of synaptic plasticity as long term potentiation (LTP) was unchanged. Immunoblot analysis of hippocampal tissue showed a significant reduction in mGlu5 receptor expression, a trend to an increase in pan Homer protein levels and a decrease in GluA1 receptor expression in the hippocampus of symptomatic WAG/Rij rats vs non-epileptic control rats. There were no changes in mGlu1α receptor or GluA2 protein levels. These findings suggest that abnormalities in hippocampal mGlu5 receptor-dependent synaptic plasticity are associated with the pathological phenotype of WAG/Rij rats. This lays the groundwork for the study of mGlu5 receptors as a candidate drug target for the treatment of cognitive dysfunction linked to absence epilepsy.

Language measurement in childhood epilepsy: A review

The psychosocial well-being of children and adolescents with epilepsy is affected by comorbid language deficits. Little is known about the focus of current research in language and epilepsy. A systematic review of research was conducted to identify gaps in knowledge regarding language and epilepsy. In total, 83 published articles were eligible for inclusion. More studies included samples presenting with focal seizures (k = 39) compared to generalized seizures (k = 10), few included measures of morphology (k = 4). Most studies (k = 66) included samples of participants across a wide age range. Our review indicated t-hat future research should include a greater focus on participants with more diversity in epilepsy etiology (e.g., symptomatic epilepsy), and seizure type (e.g., generalized seizures), assessment of additional areas of language (e.g., morphology), increased focus on early childhood, focused examination of specific developmental stages, and greater use of comparison groups with an alternate epilepsy diagnosis.

The interictal activities load and cognitive performance of children with typical absence epilepsy

Background

The description of childhood absence epilepsy (CAE) a benign self-limited generalized epilepsy has become a matter of debate. The objectives of this work were to evaluate the existence of psychiatric and cognitive impairments among patients with typical CAE and to correlate their possible relation to seizure frequency, duration of epilepsy, IISL, and valproate therapy.

Methods

The study was conducted on 19 typical CAE patients receiving valproate therapy, 11 newly diagnosed CAE patients not receiving AEDs, and 30 healthy control subjects (HCS). Participants were subjected to medical history taking, EEG monitoring, child behavior checklist (CBCL), Stanford Binet Intelligence Scale 5th edition, and computerized psychometric tests that assess cognitive domains and executive functions.

Results

The study revealed a high rate of cognitive and psychiatric dysfunctions in CAE patients. 53.3% of patients had psychiatric problems versus 16.6% in HCS. Attention deficit hyperactive disorder (ADHD) (26.6%), anxiety (16.6%), and depression (6.6%) were the most common psychiatric disorders in the patient group. Withdrawn/depressed symptoms, thought problems, social problems, and attention problems in CAE patients were significantly increased compared to HCS. At the same time, CAE patients perform worse in cognitive scales than HCS with comparable intelligent quotient (IQ) scores.

Conclusion

Cognitive and psychiatric impairments in typical CAE patients appear multifactorial in origin with epilepsy-related factors including the duration of epilepsy and interictal spike load (IISL).

Case Report: Responsive Neurostimulation of the Centromedian Thalamic Nucleus for the Detection and Treatment of Seizures in Pediatric Primary Generalized Epilepsy

Up to 20% of pediatric patients with primary generalized epilepsy (PGE) will not respond effectively to medication for seizure control. Responsive neurostimulation (RNS) is a promising therapy for pediatric patients with drug-resistant epilepsy and has been shown to be an effective therapy for reducing seizure frequency and severity in adult patients. RNS of the centromedian nucleus of the thalamus may help to prevent loss of awareness during seizure activity in PGE patients with absence seizures. Here we present a 16-year-old male, with drug-resistant PGE with absence seizures, characterized by 3 Hz spike-and-slow-wave discharges on EEG, who achieved a 75% reduction in seizure frequency following bilateral RNS of the centromedian nuclei. At 6-months post-implant, this patient reported complete resolution of the baseline daily absence seizure activity, and decrease from 3-4 generalized convulsive seizures per month to 1 per month. RNS recordings showed well-formed 3 Hz spike-wave discharges in bilateral CM nuclei, further supporting the notion that clinically relevant ictal discharges in PGE can be detected in CM. This report demonstrates that CM RNS can detect PGE-related seizures in the CM nucleus and deliver therapeutic stimulation.

Seizures and Epilepsy After Stroke: Epidemiology, Biomarkers and Management

Stroke is the leading cause of seizures and epilepsy in older adults. Patients who have larger and more severe strokes involving the cortex, are younger, and have acute symptomatic seizures and intracerebral haemorrhage are at highest risk of developing post-stroke epilepsy. Prognostic models, including the SeLECT and CAVE scores, help gauge the risk of epileptogenesis. Early electroencephalogram and blood-based biomarkers can provide information additional to the clinical risk factors of post-stroke epilepsy. The management of acute versus remote symptomatic seizures after stroke is markedly different. The choice of an ideal antiseizure medication should not only rely on efficacy but also consider adverse effects, altered pharmacodynamics in older adults, and the influence on the underlying vascular co-morbidity. Drug-drug interactions, particularly those between antiseizure medications and anticoagulants or antiplatelets, also influence treatment decisions. In this review, we describe the epidemiology, risk factors, biomarkers, and management of seizures after an ischaemic or haemorrhagic stroke. We discuss the special considerations required for the treatment of post-stroke epilepsy due to the age, co-morbidities, co-medication, and vulnerability of stroke survivors.

Absence seizures and their relationship to depression and anxiety: Evidence for bidirectionality

Absence seizures (AS), presenting as short losses of consciousness with staring spells, are a common manifestation of childhood epilepsy that is associated with behavioral, emotional, and social impairments. It has also been suggested that patients with AS are more likely to suffer from mood disorders such as depression and anxiety. This systematic review and meta-analysis synthesizes human and animal models that investigated mood disorders and AS. Of the 1019 scientific publications identified, 35 articles met the inclusion criteria for this review. We found that patients with AS had greater odds of developing depression and anxiety when compared to controls (odds ratio = 4.93, 95% confidence interval = 2.91-8.35, p < .01). The included studies further suggest a strong correlation between AS and depression and anxiety in the form of a bidirectional relationship. The current literature emphasizes that these conditions likely share underlying mechanisms, such as genetic predisposition, neurophysiology, and anatomical pathways. Further research will clarify this relationship and ensure more effective treatment for AS and mood disorders.

Etanercept rescues cognitive deficits, depression-like symptoms, and spike-wave discharge incidence in WAG/Rij rat model of absence epilepsy

Pro-inflammatory cytokines have been shown to be associated with the development of seizures in the WAG/Rij rat model of absence epilepsy. Importantly, WAG/Rij rats also exhibit cognitive deficits and depression-like behaviors. It is possible that pro-inflammatory cytokines mediate these comorbid conditions of absence epilepsy given their well-established effects on cognition and affective responses. The current study investigated the potential therapeutic effect of etanercept (tumor necrosis factor inhibitor) on cognitive impairment, depression-like behavior, and spike-wave discharges (SWDs) typically observed in the WAG/Rij rats. Eight-month-old male WAG/Rij rats and Wistar controls were tested in Morris water maze (MWM), passive avoidance (PA), forced swimming, sucrose preference, and locomotor activity tests, and electroencephalogram (EEG) recordings were taken from a separate group of WAG/Rij rats after 8 weeks of etanercept or vehicle treatment. Consistent with earlier work, WAG/Rij rats exhibited cognitive deficits and depression-like behavior. From these, the cognitive deficits and despair-like behavior were rescued by etanercept administration, which also reduced the frequency of SWDs without affecting their duration. Our results support the hypothesis that pro-inflammatory cytokines mediate the absence seizures and comorbid symptoms of absence epilepsy.

Attention deficit/hyperactivity disorder and epilepsy

PURPOSE OF REVIEW

Attention deficit/hyperactivity disorder (ADHD) is a frequent comorbidity in patients with epilepsy and is associated with important psychosocial and academic consequences. Evidence are now available to guide diagnosis and treatment of patients with both ADHD and epilepsy.

RECENT FINDINGS

The prevalence of ADHD varies from 12 to 39% in patients with newly diagnosed epilepsy to 70% in drug-resistant epilepsy. The diagnosis of ADHD requires parent-validated and teacher-validated rating scales, based on the Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV and DSM-V, to confirm the information in the rating scales by interviewing parents and to exclude other causes of symptoms. Treatment with methylphenidate is associated with clinically significant improvement of ADHD symptoms in 60-75% of patients. Recent data reinforce the hypothesis that ADHD medications do not increase risk of seizures, even in patients with epilepsy. Beyond pharmacological management, experts have recommended to include multidisciplinary involvement in transition clinics for patients with both comorbid ADHD and epilepsy.

SUMMARY

Management of ADHD in patients with epilepsy requires implementation of evidence-based data in clinical practice both for diagnosis and treatment. Currently, there is no specific treatment of ADHD associated with epilepsy and its treatment is based on the usual treatments of ADHD, with reassuring data about their safety in epilepsy.

Utility of EEG on attention deficit-hyperactivity disorder (ADHD)

OBJECTIVE

The aim of our study was to analyze electrophysiological findings in patient with Attention Deficit Hyperactivity Disorder (ADHD) by electroencephalography (EEG) recording, estimate the prevalence of epilepsy in ADHD population and assess its clinical characteristics.

METHODS

We conducted a retrospective and analytic study that concerned children with ADHD, followed for at least two-years in the Tunisian National Center for School and University Medicine (NCSUM). All patients recruited underwent at the diagnosis of ADHD, neurological examination and EEG recording in the department of Neurology of Charles Nicolle Hospital. Medical data including family history, ictal semiology and ADHD features were assessed.

RESULTS

Thirty patients were enrolled in our study. Mean age was 12.27 years with a sex ratio of 3.28. Mean age at diagnosis of ADHD was 6.6 years. Attention Deficit Hyperactivity Disordercombined subtype was seen in 18/30 patients, Hyperactive/ Impulsive subtype in 7/30 patients and Inattentive subtype in 5/30 patients. Epilepsy-disease was reported in 20% (Seizures preceded the diagnosis of ADHD in 3/6 cases and appeared after an average of 3.67 years in 3/6 cases). Mean age of seizure onset was 7 years. Seizure-types were generalized (motor 4/6 cases, absence-type (1/6 case)) and focal (1/6 case). Electroencephalography revealed Epileptiform discharges in 30% with frontal and left dominance. Interictal discharges were significantly associated with younger age of onset (p: 0.02), inattentive subtype (p: 0.04) and intellectual disability (p: 0.04). These discharges was not associated with epilepsy.

CONCLUSION

Our results have shown that epileptiform discharges could be used as risk factor for seizures and cognitive impairment which may influence outcome in ADHD population.

Clinical and experimental insight into pathophysiology, comorbidity and therapy of absence seizures

Absence seizures in children and teenagers are generally considered relatively benign because of their non-convulsive nature and the large incidence of remittance in early adulthood. Recent studies, however, show that 30% of children with absence seizures are pharmaco-resistant and 60% are affected by severe neuropsychiatric comorbid conditions, including impairments in attention, cognition, memory and mood. In particular, attention deficits can be detected before the epilepsy diagnosis, may persist even when seizures are pharmacologically controlled and are aggravated by valproic acid monotherapy. New functional MRI-magnetoencephalography and functional MRI-EEG studies provide conclusive evidence that changes in blood oxygenation level-dependent signal amplitude and frequency in children with absence seizures can be detected in specific cortical networks at least 1 min before the start of a seizure, spike-wave discharges are not generalized at seizure onset and abnormal cortical network states remain during interictal periods. From a neurobiological perspective, recent electrical recordings and imaging of large neuronal ensembles with single-cell resolution in non-anaesthetized models show that, in contrast to the predominant opinion, cortical mechanisms, rather than an exclusively thalamic rhythmogenesis, are key in driving seizure ictogenesis and determining spike-wave frequency. Though synchronous ictal firing characterizes cortical and thalamic activity at the population level, individual cortico-thalamic and thalamocortical neurons are sparsely recruited to successive seizures and consecutive paroxysmal cycles within a seizure. New evidence strengthens previous findings on the essential role for basal ganglia networks in absence seizures, in particular the ictal increase in firing of substantia nigra GABAergic neurons. Thus, a key feature of thalamic ictogenesis is the powerful increase in the inhibition of thalamocortical neurons that originates at least from two sources, substantia nigra and thalamic reticular nucleus. This undoubtedly provides a major contribution to the ictal decrease in total firing and the ictal increase of T-type calcium channel-mediated burst firing of thalamocortical neurons, though the latter is not essential for seizure expression. Moreover, in some children and animal models with absence seizures, the ictal increase in thalamic inhibition is enhanced by the loss-of-function of the astrocytic GABA transporter GAT-1 that does not necessarily derive from a mutation in its gene. Together, these novel clinical and experimental findings bring about paradigm-shifting views of our understanding of absence seizures and demand careful choice of initial monotherapy and continuous neuropsychiatric evaluation of affected children. These issues are discussed here to focus future clinical and experimental research and help to identify novel therapeutic targets for treating both absence seizures and their comorbidities.

Warped rhythms: Epileptic activity during critical periods disrupts the development of neural networks for human communication

It is well established that temporal lobe epilepsy-the most common and well-studied form of epilepsy-can impair communication by disrupting social-emotional and language functions. In pediatric epilepsy, where seizures co-occur with the development of critical brain networks, age of onset matters: The earlier in life seizures begin, the worse the disruption in network establishment, resulting in academic hardship and social isolation. Yet, little is known about the processes by which epileptic activity disrupts developing human brain networks. Here we take a synthetic perspective-reviewing a range of research spanning studies on molecular and oscillatory processes to those on the development of large-scale functional networks-in support of a novel model of how such networks can be disrupted by epilepsy. We seek to bridge the gap between research on molecular processes, on the development of human brain circuitry, and on clinical outcomes to propose a model of how epileptic activity disrupts brain development.

Absence epilepsy: Characteristics, pathophysiology, attention impairments, and the related risk of accidents. A narrative review

OBJECTIVE

Absence epilepsy (AE) is related to both cognitive and physical impairments. In this narrative review, we critically discuss the pathophysiology of AE and the impairment of attention in children and adolescents with AE. In particular, we contextualize the attentive dysfunctions of AE with the associated risks, such as accidental injuries.

DATA SOURCE

An extensive literature search on attention deficits and the rate of accidental injuries in AE was run. The search was conducted on Scopus, Pubmed, and the online libraries of the University of Twente and Maastricht University. Relevant references of the included articles were added. Retrospective and prospective studies, case reports, meta-analysis, and narrative reviews were included. Only studies written in English were considered. Date of last search is February 2020. The keywords used were "absence epilepsy" AND "attention"/"awareness", "absence epilepsy" AND "accidental injuries"/"accident*"/"injuries".

RESULTS

Ten retrospective and two prospective studies on cognition and AE were fully screened. Seventeen papers explicitly referring to attention in AE were reviewed. Just one paper was found to specifically focus on accidental injuries and AE, while twelve studies generally referring to epilepsy syndromes - among which AE - and related accidents were included.

CONCLUSION

Absence epilepsy and attention deficits show some patterns of pathophysiological association. This relation may account for dysfunctions in everyday activities in the pediatric population. Particular metrics, such as the risk related to biking in children with AE, should be used in future studies to address the problem in a novel way and to impact clinical indications.

In the eye of the beholder: Using a multiple-informant approach to examine the mediating effect of cognitive functioning on emotional and behavioral problems in children with an active epilepsy

PURPOSE

Childhood epilepsy is often associated with cognitive impairments and psychosocial problems. However, it is not clear which factors mediate symptom severity and child's resilience. Emotional and behavioral problems have been associated with various home and school environments, suggesting that information collected may vary depending on both context and informant. In this study we examined the mediating effect of child's cognitive functions on the association between child and epilepsy-related factors and psychosocial problems. Additionally, the differences in psychosocial problems reported by various informants (parents, teachers) in different school settings were explored.

METHODS

Participants were 155 children with epilepsy (50 % girls), age range 5-18 years who completed a brief neuropsychological battery. Parents completed the Child Behavior Checklist (CBCL) and teachers completed the corresponding Teacher's Rating Form (TRF), to assess a child's emotional and behavior problems.

RESULTS

The cognitive profile of the sample was within average to low-average range. Parents and teachers both reported high levels of emotional and behavioral problems, and teachers reported relatively higher levels of symptoms. A mediation effect of cognition on the association between child and epilepsy-related factors (i.e., number of antiseizure medications and illness duration) and child's emotional and behavioral problems was evident only for teachers' reports.

CONCLUSIONS

The results emphasize that the complex interactions between epilepsy, cognition and psychosocial outcomes are perceived differently in diverse contexts by different informants. The incongruities in informants' perceptions regarding the role of cognition in child's psychological state should be acknowledged and incorporated when planning effective educational and rehabilitation interventions for children with epilepsy.

Psychiatric Comorbidities in Pediatric Epilepsy

PURPOSE OF REVIEW

Psychiatric comorbidities are close to 5-times higher in children and youth with epilepsy (CYE) compared to general population. With epilepsy being one of the most common neurological disorders in children, we provide a timely review of psychiatric issues in CYE.

RECENT FINDINGS

A meta-analysis found a pooled prevalence of anxiety in 18.9% and depression in 13.5% of CYE. Attention deficit hyperactivity disorder (ADHD) is 2.5 to 5.5 times higher in CYE compared to healthy counterparts. Recent evidence highlights that behavioral adverse effects may lead to discontinuation of anti-epileptic drugs (AEDs) in more than 10% of CYE. Up to 70% CYE shows elevation in baseline psychological symptoms after AED initiation. Identifying psychiatric symptoms can be easily accomplished by the routine use of psychiatric screening instruments in CYE clinics, which is associated with improved health-related quality of life (HRQOL). Psychoeducation is a key component for any visit with CYE. There is some evidence of the effectiveness of behavioral psychological interventions for CYE. There are no therapeutic trials of psychotropics in CYE, but treatment recommendations based on the experience in adults with epilepsy and general population are applicable. Early diagnosis and management of psychiatric comorbidities leads to improvement in HRQOL of CYE. This requires routine screening and a multidisciplinary teamwork.

Reading-writing disorder in children with idiopathic epilepsy

Several studies have documented learning disabilities (LDs) in subjects with epilepsy, who have been shown to be at greater risk of mild neuropsychological damage, with the consequent risk of academic failure. This retrospective study aimed to investigate the peculiarities of reading and writing disorders in subjects with idiopathic epilepsy. The reading and writing performance of 35 children affected by reading and writing disorders and idiopathic epilepsy (R/WD + E group) has been compared with the performance of 37 children with only reading and writing disorders (R/WD group). A comparison group of 22 typical developing healthy children (TDC group) was also included in the study. As expected, the TDC group reached better performances in the reading and writing tests administered. Between R/WD + E and R/WD groups, there was a substantial analogy in reading and writing disabilities. The differences between the two clinical groups concern writing ability in sentences dictation and verbal and visuospatial short-term memory in digit span and memory-for-location (MFL) tests.

ADHD: Current Concepts and Treatments in Children and Adolescents

Attention deficit hyperactivity disorder (ADHD) is among the most frequent disorders within child and adolescent psychiatry, with a prevalence of over 5%. Nosological systems, such as the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) and the International Classification of Diseases, editions 10 and 11 (ICD-10/11) continue to define ADHD according to behavioral criteria, based on observation and on informant reports. Despite an overwhelming body of research on ADHD over the last 10 to 20 years, valid neurobiological markers or other objective criteria that may lead to unequivocal diagnostic classification are still lacking. On the contrary, the concept of ADHD seems to have become broader and more heterogeneous. Thus, the diagnosis and treatment of ADHD are still challenging for clinicians, necessitating increased reliance on their expertise and experience. The first part of this review presents an overview of the current definitions of the disorder (DSM-5, ICD-10/11). Furthermore, it discusses more controversial aspects of the construct of ADHD, including the dimensional versus categorical approach, alternative ADHD constructs, and aspects pertaining to epidemiology and prevalence. The second part focuses on comorbidities, on the difficulty of distinguishing between "primary" and "secondary" ADHD for purposes of differential diagnosis, and on clinical diagnostic procedures. In the third and most prominent part, an overview of current neurobiological concepts of ADHD is given, including neuropsychological and neurophysiological researches and summaries of current neuroimaging and genetic studies. Finally, treatment options are reviewed, including a discussion of multimodal, pharmacological, and nonpharmacological interventions and their evidence base.

Neurological disorders in autism: A systematic review and meta-analysis

LAY ABSTRACT

Neurological disorders, such as epilepsy and cerebral palsy, have been reported to occur among individuals with autism beyond chance and may have an impact on daily living across the lifespan. Although there has been research investigating neurological disorders in autism, the findings are not always conclusive. Previous summaries of existing studies have not evaluated the full range of neurological disorders. This study aimed to comprehensively explore the neurological problems appearing in autism to provide updated information that is needed for better healthcare and support in this population. We looked at already published studies focusing on risk or frequency of neurological disorders in autism. Our results suggest that individuals with autism are more likely than the general population to have a range of neurological disorders, including epilepsy, macrocephaly, hydrocephalus, cerebral palsy, migraine/headache, and inborn abnormalities of the nervous system. In order to provide individualized healthcare and support of high quality to individuals diagnosed with autism, health care professionals and other support providers need to be attentive to neurological complications. To further improve our understanding about the link between autism and neurological disorders, future research should follow the neurological health of children who are diagnosed with or are at increased likelihood of autism.

An Overview of Anxiety Disorders and Depression in Children with Epilepsy: A Literature Review

Comorbid psychiatric disorders in children with epilepsy have long been a subject of medical literature. Many studies conducted by pediatric neurologists, neurosurgeons, psychiatrists, and psychologists have revealed that psychiatric disorders, including anxiety disorders and depression, are frequently seen in children and adolescents with epilepsy. Due to various etiologies behind epilepsy, causes, manifestation, and treatment of anxiety and depression all have unique aspects. We think there are multiple reasons behind anxiety disorders and depression in children with epilepsy, varying from the physiological nature of the epilepsy itself to the environmental factors such as family, parenting, and social status. In this article, we aim to review the causes, risk factors, and management of anxiety disorders and depression in children with epilepsy.

Cortical and subcortical volume differences between Benign Epilepsy with Centrotemporal Spikes and Childhood Absence Epilepsy

OBJECTIVE

Benign Childhood Epilepsy with Centrotemporal Spikes (BECTS) and Childhood Absence Epilepsy (CAE) are the most common childhood epilepsy syndromes and they share a similar age-dependence. However, the two syndromes clearly differ in seizures and EEG patterns. The aim of this study is to investigate whether children of the same age with BECTS, CAE and typically-developing children have significant differences in grey matter volume that may underlie the different profiles of these syndromes.

METHODS

Twenty one patients with newly-diagnosed BECTS and 18 newly diagnosed and drug naïve CAE were included and compared to 31 typically-developing children. Voxel-based morphometry was utilized to investigate grey matter volume differences among BECTS, CAE, and controls. We also examined the effect of age on grey matter volume in all three groups. In addition to the whole brain analysis, we chose regions of interest analysis based on previous literature suggesting the involvement of these regions in BECTS or CAE. The group differences of grey matter volume was tested with 2-sample t-test for between two groups' comparisons and ANOVA for three group comparisons.

RESULTS

In the whole brain group comparisons, the grey matter volume in CAE was significantly decreased in the areas of right inferior frontal and anterior temporal compared to BECTS and controls (F_2,67  = 27.53, p < 0.001). In the control group, grey matter volume in bifrontal lobes showed a negative correlation with age (r=-0.54, p < 0.05), whereas no correlation was found in either CAE or BECTS. With ROI analyses, the grey matter volume of posterior thalami was increased in CAE compared to other 2 groups (p < 0.05).

SIGNIFICANCE

This study shows that there are grey matter volume differences between CAE and BECTS. Our findings of grey matter volume differences may suggest that there may be localized, specific differences in brain structure between these two types of epilepsy.

Functional brain network characteristics are associated with epilepsy severity in childhood absence epilepsy

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The functional network of children with childhood absence epilepsy is less efficiently organized in terms of clustering and small-worldness.

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Longer path lengths (i.e. less efficient organization) of the functional network relate to a longer duration of childhood absence epilepsy.

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Longer path lengths of the functional network relate to a higher seizure frequency in childhood absence epilepsy.

While cognitive impairments are not generally considered to be part of the childhood absence epilepsy (CAE) syndrome, some recent studies report cognitive, mainly attentional, deficits. Here we set out to investigate the whole brain functional network of children with CAE and controls. Furthermore, the possible relation of the functional network abnormalities with epilepsy and neurocognitive characteristics is studied.

Seventeen children with childhood CAE (aged 9.2 ± 2.1 years) and 15 controls (aged 9.8 ± 1.8 years) were included. Resting state functional MRI was acquired to study the functional network. Using graph theoretical analysis, three global metrics of the functional network were investigated: the characteristic path length, the clustering coefficient, and the small-worldness. A multivariable linear regression model including age, sex, and subject motion as covariates was used to investigate group differences in the graph metrics. Subsequently, relations of the graph metrics with epilepsy and neurocognitive characteristics were assessed.

Longer path lengths, weaker clustering and a lower small-world network topology were observed in children with CAE compared to controls. Moreover, longer path lengths were related to a longer duration of CAE and a higher number of absence seizure per hour. Clustering and small-worldness were not significantly related to epilepsy or neurocognitive characteristics.

The organization of the functional network of children with CAE is less efficient compared to controls, and is related to disease duration. These preliminary findings suggest that CAE is associated with alterations in the functional network.

Cognitive Function in Genetic Generalized Epilepsies: Insights From Neuropsychology and Neuroimaging

Genetic generalized epilepsies (GGE), previously called idiopathic generalized epilepsies, constitute about 20% of all epilepsies, and include childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy, and epilepsy with generalized tonic-clonic seizures alone (CAE, JAE, JME, and GGE-GTCS, respectively). GGE are characterized by high heritability, likely underlain by polygenetic mechanisms, which may relate to atypical neurodevelopmental trajectories. Age of onset ranges from pre-school years, for CAE, to early adulthood for GGE-GTCS. Traditionally, GGE have been considered benign, a belief contrary to evidence from neuropsychology studies conducted over the last two decades. In JME, deficits in executive and social functioning are common findings and relate to impaired frontal lobe function. Studies using neuropsychological measures and cognitive imaging paradigms provide evidence for hyperconnectivity between prefrontal and motor cortices, aberrant fronto-thalamo-cortical connectivity, and reduced fronto-cortical and subcortical gray matter volumes, which are associated with altered cognitive performance. Recent research has also identified associations between abnormal hippocampal morphometry and fronto-temporal activation during episodic memory. Longitudinal studies on individuals with newly diagnosed JME have observed cortical dysmaturation, which is paralleled by delayed cognitive development compared to the patients' peers. Comorbidities and cognitive deficits observed in other GGE subtypes, such as visuo-spatial and language deficits in both CAE and JAE, have also been correlated with atypical neurodevelopment. Although it remains unclear whether cognitive impairment profiles differ amongst GGE subtypes, effects may become more pronounced with disease duration, particularly in absence epilepsies. Finally, there is substantial evidence that patients with JME and their unaffected siblings share patterns of cognitive deficits, which is indicative of an underlying genetic etiology (endophenotype), independent of seizures and anti-epileptic medication.

Vagal nerve stimulation is effective in pre-school children with intractable epilepsy: A report of two cases

There is lack of prospective evidence regarding vagal nerve stimulator (VNS) in younger children with intractable epilepsy. Here, we report the outcomes of using VNS in two pre-school patients for pediatric intractable epilepsy (VNS-PIE) study. Medical treatment was ineffective in both the patients, and they underwent VNS implantation. Seizure frequency, score on the Gesell scale, and heart rate variability (HRV) were assessed following VNS therapy. After 6 months VNS treatment, the seizure frequency in the two patients decreased by 50% from that at baseline, based on the records in their epileptic diary. Video electroencephalography (EEG) examinations showed that abnormal fast waves diminished in the background in Patient 1, and captured seizure frequency in Patient 2 remarkably decreased. The adaptability, language, and individual and social interaction on their Gesell scales increased slightly, suggesting that VNS had a positive effect on the development of these two children. Moreover, the changes in the different HRV indices indicated improved cardiac autonomic function. In conclusion, these two cases indicated that VNS may not only be a superior therapy for pre-school children with intractable epilepsy, but also may exert a positive effect on their mental development and cardiac autonomic function.

Altered Structural Network in Newly Onset Childhood Absence Epilepsy

BACKGROUND AND PURPOSE

Recent quantitative neuroimaging studies of childhood absence epilepsy (CAE) have identified various structural abnormalities that might be involved in the onset of absence seizure and associated cognitive and behavioral functions. However, the neuroanatomical alterations specific to CAE remain unclear, and so this study investigated the regional alterations of brain structures associated with newly diagnosed CAE.

METHODS

Surface and volumetric magnetic resonance imaging data of patients with newly diagnosed CAE (n=18) and age-matched healthy controls (n=18) were analyzed using Free-Surfer software. A group comparison using analysis of covariance was performed with significance criteria of p<0.05 and p<0.01 in global and regional analyses, respectively.

RESULTS

Compared with control subjects, the patients with CAE had smaller total and regional volumes of cortical gray-matter (GM) in the right rostral middle frontal, right lateral orbitofrontal, and left rostral middle frontal regions, as well as in the right precentral, right superior, middle, left middle, and inferior temporal gyri. The cortex in the right posterior cingulate gyrus and left medial occipital region was significantly thicker in patients with CAE than in controls.

CONCLUSIONS

Patients with CAE showed a reduced bilateral frontotemporal cortical GM volume and an increased posterior medial cortical thickness, which are associated with the default mode network. These structural changes can be suggested as the neural basis of the absence seizures and neuropsychiatric comorbidities in CAE.

Towards a Better Understanding of Cognitive Deficits in Absence Epilepsy: a Systematic Review and Meta-Analysis

Cognition in absence epilepsy (AE) is generally considered undisturbed. However, reports on cognitive deficits in AE in recent years have suggested otherwise. This review systematically assesses current literature on cognitive performance in children with AE. A systematic literature search was performed in Pubmed, Embase, Cochrane and Web of Science. All studies reporting on cognitive performance in children with AE were considered. In total 33 studies were eligible for inclusion. Neuropsychological tests were classified into the following domains: intelligence; executive function; attention; language; motor & sensory-perceptual examinations; visuoperceptual/visuospatial/visuoconstructional function; memory and learning; achievement. Random-effect meta-analyses were conducted by estimating the pooled mean and/or pooling the mean difference in case-control studies. Full-scale IQ in children with AE was estimated at 96.78 (95%CI:94.46–99.10) across all available studies and in case-control studies IQ was on average 8.03 (95%CI:-10.45- -5.61) lower. Verbal IQ was estimated at 97.98 (95%CI:95.80–100.16) for all studies and 9.01 (95%CI:12.11- -5.90) points lower in case-control studies. Performance IQ was estimated at 97.23 (93.24–101.22) for all available studies and 5.32 (95%CI:-8.27–2.36) points lower in case-control studies. Lower performance was most often reported in executive function (cognitive flexibility, planning, and verbal fluency) and attention (sustained, selective and divided attention). Reports on school difficulties, neurodevelopmental problems, and attentional problems were high. In conclusion, in contrast to common beliefs, lower than average neurocognitive performance was noted in multiple cognitive domains, which may influence academic and psychosocial development.

Social cognition and psychopathology in childhood and adolescence

There is a substantial body of research on social cognition in adults with epilepsy, and in broad categories such as focal and generalized epilepsies, but much less has been written about social cognition in children with epilepsy (CWE), and in childhood-onset epilepsy syndromes specifically. In several of these syndromes, autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD), two disorders with social cognitive impairments, are reported. There is strong evidence for social cognitive deficits in juvenile myoclonic epilepsy (JME). There is also a considerable amount of evidence for such deficits in a number of syndromes that may be associated with ASD or ADHD, including West syndrome (WS), Dravet syndrome (DS), and the Landau-Kleffner syndrome (LKS). However, the evidence is of variable quality and incomplete across the range of childhood epilepsy syndromes. In some syndromes, childhood epilepsy substantially increases the risk of severe social cognitive impairment, which may persist after the seizures remit. This paper presents an overview of current research on social cognition in childhood epilepsy, with a particular focus on syndromes with a high prevalence of autistic and behavioral comorbidities. Social cognitive impairments represent a considerable additional challenge for patients and caregivers. Early diagnosis and intervention might significantly improve long-term social cognitive outcomes, highlighting the need for greater awareness among clinicians of this important topic. This article is part of the Special Issue "Epilepsy and social cognition across the lifespan".

Time perception in childhood absence epilepsy: Findings from a pilot study

OBJECTIVES

With this explorative study, we aimed to examine time perception in children with childhood absence epilepsy (CAE) and to compare those children with a matched control group. The study also investigated the association between the neuropsychological performance of the group with CAE and time judgment. We hypothesize that children with CAE could fail in time perception and that this may be because of a common underlying substrate with executive impairments.

METHODS

Thirteen children with CAE, aged 6-13 years, and 17 healthy children were recruited. All children performed the time bisection task; the children with CAE also performed a cognitive and neuropsychological assessment. We performed a univariate analysis using each parameter of the bisection task (bisection point [BP]) and Weber ratio (WR) as dependent variables, the group (patients vs. controls) as fixed factors and age at evaluation and vocabulary scores as covariates. In the subgroup of patients, we correlated bisection task parameters with neuropsychological tests using a nonparametric partial correlation; the analysis has corrected for age at evaluation.

RESULTS

The BP and WR measures differed between controls and patients with CAE. In the subgroup of patients also performing a neuropsychological assessment, we found a correlation between the WR measure and performance on the inhibition test (r = -0.641, p = .025), coding test (r = -0.815, p = .014), and Trail Making Test B (TMT B) (r = 0.72, p = .042).

CONCLUSIONS

We found an altered time perception in a pilot study of a small group of children with CAE. A neurophysiological mechanism underlying CAE seems to influence cognitive and behavioral deficits and time sensibility.

Common psychiatric comorbidities in epilepsy: How big of a problem is it?

Psychiatric illness and epilepsy commonly co-occur in adults and in children and adolescents. Theories of comorbidity are complex, but recurring associations between the conditions suggest overlap that is more than simple co-occurrence. Common underlying pathophysiology may imply that epilepsy itself may constituently include psychiatric symptoms. Conditions such as depression or cognitive difficulties commonly occur and in some cases, are considered to be associated with specific epilepsy characteristics such as localization or seizure type. Regardless of etiologic attributions to psychiatric comorbidity, it is clear today that treatment for epilepsy needs to target psychiatric illness. In many cases, quality-of-life improvements depend more upon addressing psychiatric symptoms than seizures themselves. This article is part of the Special Issue "Obstacles of Treatment of Psychiatric Comorbidities in Epilepsy".

Cognitive impairment in the WAG/Rij rat absence model is secondary to absence seizures and depressive-like behavior

Neuropsychiatric comorbidities are common in patients with epilepsy, remaining still an urgent unmet clinical need. Therefore, the management of epileptic disorders should not only be restricted to the achievement of seizure-freedom but must also be able to counteract its related comorbidities. Experimental animal models of epilepsy represent a valid tool not only to study epilepsy but also its associated comorbidities. The WAG/Rij rat is a well-established genetically-based model of absence epilepsy with depressive-like comorbidity, in which learning and memory impairment was also recently reported. Aim of this study was to clarify whether this cognitive decline is secondary or not to absence seizures and/or depressive-like behavior. The behavioral performance of untreated and ethosuximide-treated (300 mg/kg/day; 17 days) WAG/Rij rats at 6 and 12 months of age were assessed in several tests: forced swimming test, objects recognition test, social recognition test, Morris water maze and passive avoidance. According to our results, it seems that cognitive impairment in this strain, similarly to depressive-like behavior, is secondary to the occurrence of absence seizures, which might be necessary for the expression of cognitive impairment. Furthermore, our results suggest an age-dependent impairment of cognitive performance in WAG/Rij rats, which could be linked to the age-dependent increase of spike wave discharges. Consistently, it is possible that absence seizures, depressive-like behavior and cognitive deficit may arise independently and separately in lifetime from the same underlying network disease, as previously suggested for the behavioral features associated with other epileptic syndromes.

Language function in childhood idiopathic epilepsy syndromes

PURPOSE

To examine the impact of diverse syndromes of focal and generalized epilepsy on language function in children with new and recent onset epilepsy. Of special interest was the degree of shared language abnormality across epilepsy syndromes and the unique effects associated with specific epilepsy syndromes.

METHODS

Participants were 136 youth with new or recent-onset (diagnosis within past 12 months) epilepsy and 107 healthy first-degree cousin controls. The participants with epilepsy included 20 with Temporal Lobe Epilepsy (TLE; M age = 12.99  years, SD = 3.11), 41 with Benign Epilepsy with Centrotemporal Spikes (BECTS; M age = 10.32, SD = 1.67), 42 with Juvenile Myoclonic Epilepsy (JME; M age = 14.85, SD = 2.75) and 33 with absence epilepsy (M age = 10.55, SD = 2.76). All children were administered a comprehensive test battery which included multiple measures of language and language-dependent abilities (i.e., verbal intelligence, vocabulary, verbal reasoning, object naming, reception word recognition, word reading, spelling, lexical and semantic fluency, verbal list learning and delayed verbal memory). Test scores were adjusted for age and gender and analyzed via MANCOVA.

RESULTS

Language abnormalities were found in all epilepsy patient groups. The most broadly affected children were those with TLE and absence epilepsy, whose performance differed significantly from controls on 8 of 11 and 9 of 11 tests respectively. Although children with JME and BECTS were less affected, significant differences from controls were found on 4 of 11 tests each. While each group had a unique profile of language deficits, commonalities were apparent across both idiopathic generalized and localization-related diagnostic categories.

DISCUSSION

The localization related and generalized idiopathic childhood epilepsies examined here were associated with impact on diverse language abilities early in the course of the disorder.

Cognitive profile and academic achievement of children with absence epilepsy

The main aim of this study was to examine the cognitive profile and academic achievement of children with absence epilepsy. It is investigated whether all scale intelligence score, intelligence subscale scores, and academic achievement of the children with absence epilepsy differed from healthy peers and Turkish norm values. Nineteen children with absence epilepsy and 19 healthy children participate in the study. The Wechsler Intelligence Scale for Children-IV (WISC-IV) is used to measure their intelligence scores. A teacher assessment form (Teacher's Report Form (TRF)) is obtained from the participants' teachers for the measurement of academic achievement, and the students' report cards are collected as an additional measure of it. Participants with absence epilepsy have significantly lower scores of total intelligence score (Mean (M) = 76.68, Standard Deviation (SD) = 25.18), verbal comprehension score (M = 81.68, SD = 25.29), perceptual reasoning score (M = 85.47, SD = 20.61), processing speed score (M = 77.95, SD = 18.61), and working memory (M = 83.74, SD = 19.04), which are measured by WISC-IV, than healthy peers (respectively M = 105.84, SD = 16.20; M = 105.47, SD = 18.12; M = 103.63, SD = 12.88; M = 104.05, SD = 12.98; M = 104.74, SD = 18.97) and norm values (M = 100, SD = 10). No difference is observed between the subscale scores of WISC-IV for within group with absence epilepsy. Moreover, they have lower Turkish language (M = 73.65, SD = 19.19) and mathematics (M = 76.26, SD = 22.29) grade report scores than healthy peers (respectively M = 90.76, SD = 12.01; M = 88.64, SD = 15.93). There is no difference between the two groups in terms of the academic achievement obtained from the TRF. It is necessary to support children with absence epilepsy academically. We analyzed whether the current pattern has changed by comparing the intelligent scores and academic achievement of children with absence epilepsy who have recovered after treatment with their healthy peers. In fact, there is no difference between the children with absence epilepsy who have recovered after treatment and their healthy peers in terms of total intelligence score and its subscale scores. Similarly, there is no difference between them in terms of mathematics score on their report. Only the difference in the score of Turkish language continues in the same direction.

Cognitive development in absence epilepsy during long-term follow-up

Absence epilepsy (AE) has been associated with lower than average cognitive functioning, which are clinically relevant in some and may predispose to problems later in life. This study aimed to assess cognitive development during long-term follow-up in children with AE. Thirty-one children with AE, who had undergone two neuropsychological assessments between 2010 and 2017 were analyzed retrospectively. Cognitive measurements were 1.7 ± 0.95 years apart. The difference in neurocognitive test scores was assessed on a group level and on an individual level using reliable change methodology. Results show that sustained attention was lower at the first measurement compared to the normative mean. Sustained attention improved during follow-up and 7 out of 14 children showed improvement after correction for practice effects. Receptive vocabulary showed a decline over time, but did not differ from the normative mean. Significant lower mean group scores were present for performance IQ, perceptual organization, processing speed, simple reaction times, and visual motor integration, while being stable over time in the majority of children. Cognitive development was not associated with seizure freedom. Mild-to-severe academic underachievement was present in 65% and comorbidities that might affect learning in 38%. This study in children with AE showed improvement in sustained attention during long-term follow-up while other cognitive weaknesses persisted over time, regardless of seizure freedom.

Historical trend toward improved long-term outcome in childhood absence epilepsy

We retrospectively analyzed published studies to investigate historical trends in outcome of childhood absence epilepsy (CAE). We included patients based on onset of absence seizures in childhood, 3 Hz bilateral spike-wave discharges on EEG, and availability of seizure-free outcome data. The primary endpoint was seizure-freedom off medications by study publication year. We also analyzed relationships between seizure-freedom and 1. treatment medication, and 2. CAE diagnostic criteria. We included 29 studies published 1945-2013, encompassing 2416 patients. Seizure-freedom off medications was higher for studies after 1985 versus before 1975 (82% versus 35%; p < 0.001). Ethosuximide and valproate were used more commonly after 1985, and patients previously treated with ethosuximide or valproate had higher seizure-freedom off medications than those treated only with other medications (64% versus 32%; χ²>10; p < 0.001). Although differences in diagnostic criteria for early vs. later studies did not reach statistical significance, later studies tended to use normal EEG background (p = 0.09) and absence of comorbid disorders (p = 0.09) as criteria more commonly. These findings demonstrate that seizure-freedom off medications has improved in published CAE studies after 1985. Our results are limited due to retrospective analysis. Further work is needed with prospective, controlled trials to establish factors leading to improved long-term prognosis in CAE.

A Practical Guide to Treatment of Childhood Absence Epilepsy

Childhood absence epilepsy (CAE) is a common pediatric epilepsy syndrome with distinct seizure semiology, electroencephalography (EEG) features, and treatment. A diagnosis of CAE can be obtained during an office visit with a careful history, physical exam including prolonged hyperventilation, and a routine EEG. The treatment of choice for CAE with absence seizures only is ethosuximide. Valproic acid and lamotrigine are also effective treatments for many patients, but when compared to ethosuximide, valproic acid has more adverse effects and lamotrigine is less effective. Attention to predictors of response to treatment, including clinical, electrographic, and genetic factors, is increasing. Refractory CAE occurs in fewer than half of patients, and treatment strategies are available, though efficacy data are lacking. Careful assessment and treatment of psychosocial comorbidities is essential in caring for patients with CAE.

Out of thin air: Hyperventilation-triggered seizures

Voluntary hyperventilation triggers seizures in the vast majority of people with absence epilepsy. The mechanisms that underlie this phenomenon remain unknown. Herein, we review observations - many made long ago - that provide insight into the relationship between breathing and absence seizures.

Vagus nerve stimulation for pediatric patients with intractable epilepsy between 3 and 6 years of age: study protocol for a double-blind, randomized control trial

BACKGROUND

Recent clinical observations have reported the potential benefit of vagus nerve stimulation (VNS) as an adjunctive therapy for pediatric epilepsy. Preliminary evidence suggests that VNS treatment is effective for seizure reduction and mental development in young participants between 3 and 6 years of age who suffer from intractable epilepsy. However, robust clinical evidence for quantifying the difference of the efficacy and safety of VNS treatment in this specific patient population has yet to be reported.

METHODS/DESIGN

A two-armed, multicenter, randomized, double-blind, prospective trial will be carried out to evaluate whether VNS is beneficial and safe for pediatric epilepsy. Pediatric participants aged between 3 to 6 years old with intractable epilepsy will be recruited and randomly assigned to experimental and control groups with a 1:1 allocation using a computer-generating randomization schedule. Before enrollment, informed consent will be signed by the parents of the participants and the study researchers. Participants in the experimental group will receive electrical stimulation over 24 weeks under standard stimulation parameters. Participants in the control group will not receive any stimulation during the 12 weeks of the double-blind period. The guardians of the participants are required to keep a detailed diary to record seizure activity. Outcome assessments including seizure frequency, Gesell Mental Developmental Scale scores, use of antiepileptic drugs and dosages, and adverse events will be collected at baseline, 6, 12, 18 and/or 24 weeks after electrical stimulation is initiated. The effects of treatment will be analyzed with time and treatment group comparisons.

DISCUSSION

This trial will evaluate quantitative differences in efficacy and safety with/without VNS treatment for pediatric participants aged between 3 to 6 years with intractable epilepsy and will explore whether the current age range of VNS therapy can be expanded.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT03062514 , Registered on 23 February 2017.

Sensory coding is impaired in rat absence epilepsy

KEY POINTS

Absence epilepsy is characterized by the occurrence of spike-and-wave discharges concomitant with an alteration of consciousness and is associated with cognitive comorbidities. In a genetic model of absence epilepsy in the rat, the genetic absence epilepsy rat from Strasbourg (GAERS), spike-and-wave discharges are shown to be initiated in the barrel field primary somatosensory cortex that codes whisker-related information, therefore playing an essential role in the interactions of rodents with their environment. Sensory-information processing is impaired in the epileptic barrel field primary somatosensory cortex of GAERS, with a delayed sensory-evoked potential and a duplicated neuronal response to whisker stimulation in in vivo extracellular recordings. Yet, GAERS present no defaults of performance in a texture discrimination task, suggesting the existence of a compensatory mechanism within the epileptic neuronal network. The results of the present study indicate that physiological primary functions are processed differently in an epileptic cortical network.

ABSTRACT

Several neurodevelopmental pathologies are associated with disorganized cortical circuits that may alter primary functions such as sensory processes. In the present study, we investigated whether the function of a cortical area is altered in the seizure onset zone of absence epilepsy, a prototypical form of childhood genetic epilepsy associated with cognitive impairments. We first combined in vivo multichannel electrophysiological recordings and histology to precisely localize the seizure onset zone in the genetic absence epilepsy rat from Strasbourg (GAERS). We then investigated the functionality of this epileptic zone using extracellular silicon probe recordings of sensory-evoked local field potentials and multi-unit activity, as well as a behavioural test of texture discrimination. We show that seizures in this model are initiated in the barrel field part of the primary somatosensory cortex and are associated with high-frequency oscillations. In this cortex, we found an increased density of parvalbumin-expressing interneurons in layer 5 in GAERS compared to non-epileptic Wistar rats. Its functional investigation revealed that sensory abilities of GAERS are not affected in a texture-discrimination task, whereas the intracortical processing of sensory-evoked information is delayed and duplicated. Altogether, these results suggest that absence seizures are associated with an increase of parvalbumin-inhibitory neurons, which may promote the functional relationship between epileptic oscillations and high-frequency activities. Our findings suggest that cortical circuits operate differently in the epileptic onset zone and may adapt to maintain their ability to process highly specialized information.