Neuropsychological impairment in childhood absence epilepsy: Review of the literature

Home recording of 3-Hz spike-wave discharges in adults with absence epilepsy using the wearable Sensor Dot

OBJECTIVE

Home monitoring of 3-Hz spike-wave discharges (SWDs) in patients with refractory absence epilepsy could improve clinical care by replacing the inaccurate seizure diary with objective counts. We investigated the use and performance of the Sensor Dot (Byteflies) wearable in persons with absence epilepsy in their home environment.

METHODS

Thirteen participants (median age = 22 years, 11 female) were enrolled at the university hospitals of Leuven and Freiburg. At home, participants had to attach the Sensor Dot and behind-the-ear electrodes to record two-channel electroencephalogram (EEG), accelerometry, and gyroscope data. Ground truth annotations were created during a visual review of the full Sensor Dot recording. Generalized SWDs were annotated if they were 3 Hz and at least 3 s on EEG. Potential 3-Hz SWDs were flagged by an automated seizure detection algorithm, (1) using only EEG and (2) with an additional postprocessing step using accelerometer and gyroscope to discard motion artifacts. Afterward, two readers (W.V.P. and L.S.) reviewed algorithm-labeled segments and annotated true positive detections. Sensitivity, precision, and F1 score were calculated. Patients had to keep a seizure diary and complete questionnaires about their experiences.

RESULTS

Total recording time was 394 h 42 min. Overall, 234 SWDs were captured in 11 of 13 participants. Review of the unimodal algorithm-labeled recordings resulted in a mean sensitivity of .84, precision of .93, and F1 score of .89. Visual review of the multimodal algorithm-labeled segments resulted in a similar F1 score and shorter review time due to fewer false positive labels. Participants reported that the device was comfortable and that they would be willing to wear it on demand of their neurologist, for a maximum of 1 week or with intermediate breaks.

SIGNIFICANCE

The Sensor Dot improved seizure documentation at home, relative to patient self-reporting. Additional benefits were the short review time and the patients' device acceptance due to user-friendliness and comfortability.

Behavioral and Cognitive Comorbidities in Genetic Rat Models of Absence Epilepsy (Focusing on GAERS and WAG/Rij Rats)

Absence epilepsy is a non-convulsive type of epilepsy characterized by the sudden loss of awareness. It is associated with thalamo-cortical impairment, which may cause neuropsychiatric and neurocognitive problems. Rats with spontaneous absence-like seizures are widely used as in vivo genetic models for absence epilepsy; they display behavioral and cognitive problems similar to epilepsy in humans, such as genetic absence epilepsy rats from Strasbourg (GAERS) and Wistar Albino rats from Rijswijk (WAG/Rij). Depression- and anxiety-like behaviors were apparent in GAERS, but no anxiety and depression-like symptoms were found in WAG/Rij rats. Deficits in executive functions and memory impairment in WAG/Rij rats, i.e., cognitive comorbidities, were linked to the severity of epilepsy. Wistar rats can develop spontaneous seizures in adulthood, so caution is advised when using them as a control epileptic strain. This review discusses challenges in the field, such as putative high emotionality in genetically prone rats, sex differences in the expression of cognitive comorbidities, and predictors of cognitive problems or biomarkers of cognitive comorbidities in absence epilepsy, as well as the concept of "the cognitive thalamus". The current knowledge of behavioral and cognitive comorbidities in drug-naive rats with spontaneous absence epilepsy is beneficial for understanding the pathophysiology of absence epilepsy, and for finding new treatment strategies.

Quantitative MRI reveals widespread, network-specific myelination change during generalized epilepsy progression

Activity-dependent myelination is a fundamental mode of brain plasticity which significantly influences network function. We recently discovered that absence seizures, which occur in multiple forms of generalized epilepsy, can induce activity-dependent myelination, which in turn promotes further progression of epilepsy. Structural alterations of myelin are likely to be widespread, given that absence seizures arise from an extensive thalamocortical network involving frontoparietal regions of the bilateral hemispheres. However, the temporal course and spatial extent of myelin plasticity is unknown, due to limitations of gold-standard histological methods such as electron microscopy (EM). In this study, we leveraged magnetization transfer and diffusion MRI for estimation of g-ratios across major white matter tracts in a mouse model of generalized epilepsy with progressive absence seizures. EM was performed on the same brains after MRI. After seizure progression, we found increased myelination (decreased g-ratios) throughout the anterior portion (genu-to-body) of the corpus callosum but not in the posterior portion (body-splenium) nor in the fornix or the internal capsule. Curves obtained from averaging g-ratio values at every longitudinal point of the corpus callosum were statistically different with p<0.001. Seizure-associated myelin differences found in the corpus callosum body with MRI were statistically significant (p = 0.0027) and were concordant with EM in the same region (p = 0.01). Notably, these differences were not detected by diffusion tensor imaging. This study reveals widespread myelin structural change that is specific to the absence seizure network. Furthermore, our findings demonstrate the potential utility and importance of MRI-based g-ratio estimation to non-invasively detect myelin plasticity.

School performance and psychiatric comorbidity in childhood absence epilepsy: A Danish cohort study

The aim was to determine school performance and psychiatric comorbidity in children with childhood absence epilepsy (CAE). We reviewed the medical records in children with ICD-10 codes for idiopathic generalized epilepsy before 18 years of age, and pediatric neurologists confirmed the International League Against Epilepsy criteria for CAE were met. Control groups were the general pediatric population or children with non-neurological chronic disease. Outcomes were from nationwide and population-based registers on school performance and psychiatric comorbidity. We compared the mean grade point average using linear regression and estimated hazard ratios (HR) using Cox regression for the other outcomes. Analyses were adjusted for the child's sex, and year of birth, and parental highest education, receipt of cash benefits or early disability pension. We included 114 children with CAE with a median age at onset of 5.9 years (interquartile range = 4.5-7.3 years). Compared with both population controls and non-neurological chronically ill children, children with CAE had increased hazard of special needs education (HR = 2.7, 95% confidence interval (CI) = 1.8-4.1, p < 0.0001), lower grade point average at 9th grade by 1.7 grade points (95% CI = -2.5 to -1.0, p < 0.001), increased ADHD medicine use (HR = 4.4, 95% CI = 2.7-7.2, p < 0.001), increased sleep medicine use (HR = 2.7, 95% CI = 1.7-4.3, p < 0.001), and increased psychiatry visits (HR = 2.1, 95% CI = 1.1-4.0, p = 0.03). In conclusion, children with CAE have increased psychiatric comorbidity and a considerable proportion of these children receive special needs education in primary/secondary school, albeit insufficient to normalize their considerably lower grade point average in the 9th grade.

Towards Zebrafish Models of CNS Channelopathies

Channelopathies are a large group of systemic disorders whose pathogenesis is associated with dysfunctional ion channels. Aberrant transmembrane transport of K⁺, Na⁺, Ca²⁺ and Cl^- by these channels in the brain induces central nervous system (CNS) channelopathies, most commonly including epilepsy, but also migraine, as well as various movement and psychiatric disorders. Animal models are a useful tool for studying pathogenesis of a wide range of brain disorders, including channelopathies. Complementing multiple well-established rodent models, the zebrafish (Danio rerio) has become a popular translational model organism for neurobiology, psychopharmacology and toxicology research, and for probing mechanisms underlying CNS pathogenesis. Here, we discuss current prospects and challenges of developing genetic, pharmacological and other experimental models of major CNS channelopathies based on zebrafish.

Temporal and spatial dynamic propagation of electroencephalogram by combining power spectral and synchronization in childhood absence epilepsy

Objective

During the transition from normal to seizure and then to termination, electroencephalography (EEG) signals have complex changes in time-frequency-spatial characteristics. The quantitative analysis of EEG characteristics and the exploration of their dynamic propagation in this paper would help to provide new biomarkers for distinguishing between pre-ictal and inter-ictal states and to better understand the seizure mechanisms.

Methods

Thirty-three children with absence epilepsy were investigated with EEG signals. Power spectral and synchronization were combined to provide the time-frequency-spatial characteristics of EEG and analyze the spatial distribution and propagation of EEG in the brain with topographic maps. To understand the mechanism of spatial-temporal evolution, we compared inter-ictal, pre-ictal, and ictal states in EEG power spectral and synchronization network and its rhythms in each frequency band.

Results

Power, frequency, and spatial synchronization are all enhanced during the absence seizures to jointly dominate the epilepsy process. We confirmed that a rapid diffusion at the onset accompanied by the frontal region predominance exists. The EEG power rapidly bursts in 2–4 Hz through the whole brain within a few seconds after the onset. This spatiotemporal evolution is associated with spatial diffusion and brain regions interaction, with a similar pattern, increasing first and then decreasing, in both the diffusion of the EEG power and the connectivity of the brain network during the childhood absence epilepsy (CAE) seizures. Compared with the inter-ictal group, we observed increases in power of delta and theta rhythms in the pre-ictal group (P < 0.05). Meanwhile, the synchronization of delta rhythm decreased while that of alpha rhythm enhanced.

Conclusion

The initiation and propagation of CAE seizures are related to the abnormal discharge diffusion and the synchronization network. During the seizures, brain activity is completely changed with the main component delta rhythm. Furthermore, this article demonstrated for the first time that alpha inhibition, which is consistent with the brain’s feedback regulation mechanism, is caused by the enhancement of the network connection. Temporal and spatial evolution of EEG is of great significance for the transmission mechanism, clinical diagnosis and automatic detection of absence epilepsy seizures.

Absence seizures during sleep in childhood absence epilepsy: A sign of drug resistance?

BACKGROUND

Childhood absence epilepsy (CAE) is a common pediatric epilepsy syndrome. It is characterized by typical absence seizures and a highly recognizable electroencephalography (EEG) pattern. But little is known about absence seizures during sleep.

CASE REPORT

A 7-year-old female presented with frequent typical absence seizures with 3 Hz generalized spike and wave discharges on EEG. Based on electro-clinical features she was diagnosed with CAE. When she was 8 years old, absence seizures occurred during sleep. She had refractory absence seizures even with valproic acid, lamotrigine, levetiracetam, and perampanel.

CONCLUSION

Absence seizures can occur during sleep in CAE. Absence seizures should be considered, especially when 3 Hz generalized spike and wave discharges last >2 s on EEG during sleep. It may be a sign of drug resistance and poor prognosis.

Multimodal connectome biomarkers of cognitive and affective dysfunction in the common epilepsies

Epilepsy is one of the most common chronic neurological conditions, traditionally defined as a disorder of recurrent seizures. Cognitive and affective dysfunction are increasingly recognized as core disease dimensions and can affect patient well-being, sometimes more than the seizures themselves. Connectome-based approaches hold immense promise for revealing mechanisms that contribute to dysfunction and to identify biomarkers. Our review discusses emerging multimodal neuroimaging and connectomics studies that highlight network substrates of cognitive/affective dysfunction in the common epilepsies. We first discuss work in drug-resistant epilepsy syndromes, that is, temporal lobe epilepsy, related to mesiotemporal sclerosis (TLE), and extratemporal epilepsy (ETE), related to malformations of cortical development. While these are traditionally conceptualized as ‘focal’ epilepsies, many patients present with broad structural and functional anomalies. Moreover, the extent of distributed changes contributes to difficulties in multiple cognitive domains as well as affective-behavioral challenges. We also review work in idiopathic generalized epilepsy (IGE), a subset of generalized epilepsy syndromes that involve subcortico-cortical circuits. Overall, neuroimaging and network neuroscience studies point to both shared and syndrome-specific connectome signatures of dysfunction across TLE, ETE, and IGE. Lastly, we point to current gaps in the literature and formulate recommendations for future research.

Epilepsy is increasingly recognized as a network disorder characterized by recurrent seizures as well as broad-ranging cognitive difficulties and affective dysfunction. Our manuscript reviews recent literature highlighting brain network substrates of cognitive and affective dysfunction in common epilepsy syndromes, namely temporal lobe epilepsy secondary to mesiotemporal sclerosis, extratemporal epilepsy secondary to malformations of cortical development, and idiopathic generalized epilepsy syndromes arising from subcortico-cortical pathophysiology. We discuss prior work that has indicated both shared and distinct brain network signatures of cognitive and affective dysfunction across the epilepsy spectrum, improves our knowledge of structure-function links and interindividual heterogeneity, and ultimately aids screening and monitoring of therapeutic strategies.

Similar Profile and Magnitude of Cognitive Impairments in Focal and Generalized Epilepsy: A Pilot Study

Introduction: Cognitive impairments in epilepsy are not well-understood. In addition, long-term emotional, interpersonal, and social consequences of the underlying disturbances are important to evaluate.

Purpose: To compare cognitive function including language in young adults with focal or generalized epilepsy. In addition, quality of life and self-esteem were investigated.

Patients and Methods: Young adults with no primary intellectual disability, 17 with focal epilepsy and 11 with generalized epilepsy participated and were compared to 28 healthy controls. Groups were matched on age (mean = 26 years), sex, and education. Participants were administered a battery of neuropsychological tasks and carried out self-ratings of quality of life, self-esteem, and psychological problems.

Results: Similar impairments regarding cognitive function were noted in focal and generalized epilepsy. The cognitive domains tested were episodic long-term memory, executive functions, attention, working memory, visuospatial functions, and language. Both epilepsy groups had lower results compared to controls (effect sizes 0.24–1.07). The total number of convulsive seizures was predictive of episodic long-term memory function. Participants with focal epilepsy reported lower quality of life than participants with generalized epilepsy. Lowered self-esteem values were seen in both epilepsy groups and particularly in those with focal epilepsy. Along with measures of cognitive speed and depression, the total number of seizures explained more than 50% of variation in quality of life.

Conclusion: Interestingly, similarities rather than differences characterized the widespread cognitive deficits that were seen in focal and generalized epilepsy, ranging from mild to moderate. These similarities were modified by quality of life and self-esteem. This study confirms the notion that epilepsy is a network disorder.

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.

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.

Epilepsy and other seizure disorders in acute psychiatric inpatients

BACKGROUND

It is well known that patients with epilepsy have a high rate of psychiatric comorbidity. However, studies exploring epilepsy in psychiatric cohorts are scarce. The aim of this study was to examine the prevalence of seizure disorders in acute psychiatric inpatients.

METHODS

This is a cross-sectional study performed in a catchment-area based acute psychiatric department. All patients (age > 18) admitted during September 2011 - March 2012 were eligible for inclusion. Consenting patients were screened for a life-time history of epilepsy or seizures using self-reported questionnaire data and diagnostic codes for epilepsy in hospital and National registries. Patients scoring positive to one or more of these screening criteria underwent a thorough diagnostic validation (chart review), and the seizure disorders were classified as epilepsy, acute symptomatic seizures and/or psychogenic non-epileptic seizures according to current definitions.

RESULTS

A total of 380 out of 591 (64.3%) consecutively admitted patients consented to participate in the study. Eighty-nine patients (23.4%) scored positive to one or more screening criteria. Fifteen (3.9%) were classified with epilepsy, 21 (5.5%) with acute symptomatic seizures and 9 (2.4%) with psychogenic non-epileptic seizures.

CONCLUSIONS

This is the first study to report on the prevalence of seizure disorders in acute psychiatric inpatients. The life-time prevalence of epilepsy in this cohort of patients is five - six times as high as reports in the general population. These findings underscore the need for the clinical psychiatrist to have comprehensive knowledge on the interface between epileptology and psychiatry.

TRIALS REGISTRATION

ClinicalTrials.gov identifier NCT01415323 .

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.

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).

5-HT/GABA interaction in epilepsy

Epilepsy is a neurological condition characterized by synchronous neuronal oscillations (seizures) in the electroencephalogram. Seizures are classified in focal or generalized (depending on the brain territory interested during seizures), and in convulsive and/or not convulsive (depending on the presence or not of involuntary movements). The current pharmacological treatments are mainly based on GABA modulation although different neurotransmitters are also involved in epilepsy, including serotonin. However despite much extensive progress in the understanding of epilepsy mechanisms, still, a percentage of people with epilepsy are pharmaco-resistant calling for the need for new therapeutic targets. Here we review preclinical and human evidence showing that serotonin modulates epilepsy that this likely happens via a major modulation/interaction with GABA.

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.

Network, clinical and sociodemographic features of cognitive phenotypes in temporal lobe epilepsy

This study explored the taxonomy of cognitive impairment within temporal lobe epilepsy and characterized the sociodemographic, clinical and neurobiological correlates of identified cognitive phenotypes. 111 temporal lobe epilepsy patients and 83 controls (mean ages 33 and 39, 57% and 61% female, respectively) from the Epilepsy Connectome Project underwent neuropsychological assessment, clinical interview, and high resolution 3T structural and resting-state functional MRI. A comprehensive neuropsychological test battery was reduced to core cognitive domains (language, memory, executive, visuospatial, motor speed) which were then subjected to cluster analysis. The resulting cognitive subgroups were compared in regard to sociodemographic and clinical epilepsy characteristics as well as variations in brain structure and functional connectivity. Three cognitive subgroups were identified (intact, language/memory/executive function impairment, generalized impairment) which differed significantly, in a systematic fashion, across multiple features. The generalized impairment group was characterized by an earlier age at medication initiation (P < 0.05), fewer patient (P < 0.001) and parental years of education (P < 0.05), greater racial diversity (P < 0.05), and greater number of lifetime generalized seizures (P < 0.001). The three groups also differed in an orderly manner across total intracranial (P < 0.001) and bilateral cerebellar cortex volumes (P < 0.01), and rate of bilateral hippocampal atrophy (P < 0.014), but minimally in regional measures of cortical volume or thickness. In contrast, large-scale patterns of cortical-subcortical covariance networks revealed significant differences across groups in global and local measures of community structure and distribution of hubs. Resting-state fMRI revealed stepwise anomalies as a function of cluster membership, with the most abnormal patterns of connectivity evident in the generalized impairment group and no significant differences from controls in the cognitively intact group. Overall, the distinct underlying cognitive phenotypes of temporal lobe epilepsy harbor systematic relationships with clinical, sociodemographic and neuroimaging correlates. Cognitive phenotype variations in patient and familial education and ethnicity, with linked variations in total intracranial volume, raise the question of an early and persisting socioeconomic-status related neurodevelopmental impact, with additional contributions of clinical epilepsy factors (e.g., lifetime generalized seizures). The neuroimaging features of cognitive phenotype membership are most notable for disrupted large scale cortical-subcortical networks and patterns of functional connectivity with bilateral hippocampal and cerebellar atrophy. The cognitive taxonomy of temporal lobe epilepsy appears influenced by features that reflect the combined influence of socioeconomic, neurodevelopmental and neurobiological risk factors.

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.

Parental report of quality of life in children with epilepsy: A Spanish/French comparison

BACKGROUND

Epilepsy is a chronic neurological condition that affects the quality of life (QoL) of patients and their families. In this study, we compare two sets of reports on QoL that were completed by two samples of parents whose children have epilepsy.

METHOD

Parents of children with various types of epilepsy from Spain (N = 196) and France (N = 219) completed the same QoL questionnaire. Medical variables were recorded from the referred specialist doctor for each patient.

RESULTS

The factors associated with parental reports on QoL were similar in both countries. Parents of children with nonidiopathic generalized or unclassified epilepsy reported poorer QoL and the highest proportion of learning and behavioral problems. However, the intensity of difficulties varied between the two samples.

CONCLUSIONS

This questionnaire made it possible to detect comorbidities and daily life difficulties in children with epilepsy and their families. The type of epilepsy had the same influence on Spanish and French families' ratings of QoL. Families shared the same comorbidities in terms of hyperactivity/attention/sociability problems. Nevertheless, the intensity of reported difficulties varied in both countries, possibly because of differences in cultural and educational environments. This aspect should be further explored in future research.

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.

Epilepsy

Epilepsy is considered a disease characterized by an underlying predisposition to seizures as well as neurobiologic, cognitive, psychologic, and social consequences. It is the most frequent chronic neurologic condition of childhood, affecting 0.5%-1% of children worldwide. It comprises a variety of disorders with many different etiologies, consequently affecting management and outcome. Although the great majority of children have epilepsies that are self-limited and have a good prognosis, it is nevertheless very well recognized that epileptic activity (be it seizures or interictal discharges) can be particularly deleterious to the developing brain acting as a disruptor to normal developmental function. Indeed, epilepsy and neurocognitive and behavioral disorders very frequently coexist, and it can be challenging to understand if there is causality or if they are all the reflection of the underlying brain disorder. Hence, accurate phenotypic and etiologic diagnosis is of utmost importance as it will not only guide decision making with regard to choice of treatment but also enable management of expectations concerning outcome. The current chapter aims to provide a general overview of the fast evolving and vast field of childhood epilepsy from its definition and epidemiology, to its diagnostic challenges, management, and outcome.

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.

Polysomnographic Findings in Fragile X Syndrome Children with EEG Abnormalities

Fragile X syndrome (FXS) is a genetic syndrome with intellectual disability due to the loss of expression of the FMR1 gene located on chromosome X (Xq27.3). This mutation can suppress the fragile X mental retardation protein (FMRP) with an impact on synaptic functioning and neuronal plasticity. Among associated sign and symptoms of this genetic condition, sleep disturbances have been already described, but few polysomnographic reports in pediatric age have been reported. This multicenter case-control study is aimed at assessing the sleep macrostructure and at analyzing the presence of EEG abnormalities in a cohort of FXS children. We enrolled children with FXS and, as controls, children with typical development. All subjects underwent at least 1 overnight polysomnographic recording (PSG). All recorded data obtained from patients and controls were compared. In children with FXS, all PSG-recorded parameters resulted pathological values compared to those obtained from controls, and in FXS children only, we recorded interictal epileptiform discharges (IEDs), as diffuse or focal spikes and sharp waves, usually singles or in brief runs with intermittent or occasional incidence. A possible link between IEDs and alterations in the circadian sleep-wake cycle may suggest a common dysregulation of the balance between inhibitory and excitatory pathways in these patients. The alteration in sleep pattern in children with FXS may negatively impact the neuropsychological and behavioral functioning, adding increasing burn of the disease on the overall management of these patients. In this regard, treating physicians have to early detect sleep disturbances in their patients for tailored management, in order to prevent adjunctive comorbidities.

Single-subject manual independent component analysis and resting state fMRI connectivity outcomes in patients with juvenile absence epilepsy

The quality of fMRI data impacts functional connectivity measures and consequently, the decisions that clinicians and researchers make regarding functional connectivity interpretation. The present study used resting state fMRI to investigate resting state network connectivity in a sample of patients with Juvenile Absence Epilepsy. Single-subject manual independent component analysis was used in two levels, whereby all noise components were removed, and cerebrospinal fluid pulsation components only were isolated and removed. Improved temporal signal to noise ratios and functional connectivity metrics were observed in each of the cleaning levels for both epilepsy and control cohorts. Results showed full, single-subject manual independent component analysis reduced the number of functional connectivity correlations and increased the strength of these correlations. Similar effects were also observed for the cerebrospinal fluid pulsation only cleaned data relative to the uncleaned, and fully cleaned data. Single-subject manual independent component analysis coupled with short TR multiband acquisition can significantly improve the validity of findings derived from fMRI data sets.

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.

The role of task-based neural activation research in understanding cognitive deficits in pediatric epilepsy

Children with epilepsy can experience significant cognitive dysfunction that can lead to academic underachievement. Traditionally believed to be primarily due to the effects of factors such as the chronicity of epilepsy, medication effects, or the location of the primary epileptogenic lesion;, recent evidence has indicated that disruption of cognition-specific distributed neural networks may play a significant role as well. Specifically, over the last decade, researchers have begun to characterize the mechanisms underlying disrupted cognitive substrates by evaluating neural network abnormalities observed during specific cognitive tasks, using task-based functional magnetic resonance imaging (fMRI). This targeted review assesses the current literature investigating the relationship between neural network abnormalities and cognitive deficits in pediatric epilepsy. The findings indicate that there are indeed neural network abnormalities associated with deficits in executive function, language, processing speed, and memory. Overall, cognitive dysfunction in pediatric epilepsy is associated with a decrease in neural network activation/deactivation as well as increased recruitment of brain regions not typically related to the specific cognitive task under investigation. The research to date has focused primarily on children with focal epilepsy syndromes with small sample sizes and differing research protocols. More extensive research in children with a wider representation of epilepsy syndromes (including generalized epilepsy syndromes) is necessary to fully understand these relationships and begin to identify underlying cognitive phenotypes that may account for the variability observed across children with epilepsy. Furthermore, more uniformity in fMRI protocols and neuropsychological tasks would be ideal to advance this literature.

Antiepileptogenic effects of Ethosuximide and Levetiracetam in WAG/Rij rats are only temporary

BACKGROUND

WAG/Rij rats represent a validated genetic animal model of epileptogenesis, absence epilepsy and depressive-like comorbidity. Some treatments (e.g. ethosuximide), using specific protocols, prevent the development of spontaneous absence seizures. Accordingly, ethosuximide increases remission occurrence in children with childhood absence epilepsy in comparison to valproic acid. Considering that in this animal model, antiepileptogenic effects are, in some cases, not retained over time, we studied whether the antiepileptogenic effects of both ethosuximide and levetiracetam (which also possesses antiepileptogenic effects in this and other animal epilepsy models) would be retained 5 months after drug suspension.

METHODS

WAG/Rij rats of ˜1 month of age were treated long-term with one of the two drugs at a dose of ˜80 mg/kg/day for 17 consecutive weeks; 1 and 5 months after drug suspension, the development of absence seizures as well as depressive-like behaviour were assessed by EEG recordings and the forced swimming test (FST).

RESULTS

In agreement with a previous report, both drugs continued to show antiepileptogenic effects 1 month after their discontinuation. Furthermore, ethosuximide improved depressive-like behaviour, whereas in contrast, levetiracetam worsened this symptom. However, none of the drugs maintained their antiepileptogenic effects 5 months after suspension, and in addition, animal behaviour in the FST returned to control conditions.

CONCLUSION

Overall, these results demonstrate that the antiepileptogenic effects of both ethosuximide and levetiracetam on absence seizure development and associated depressive-like behaviour in this model are only temporary.

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.

Lower myelin-water content of the frontal lobe in childhood absence epilepsy

OBJECTIVE

The frontal lobe in childhood absence epilepsy (CAE) might be affected due to the suggested involvement of the frontal lobe during absence seizures and reports on attentional deficits. Previously, subtle white matter abnormalities have been reported in CAE. However, the impact of one of the most characteristic components of the white matter, the myelin content, remains underdetermined. Therefore, this study investigated whether the myelin content in frontal areas is adversely affected in CAE compared to controls.

METHODS

Seventeen children with childhood absence epilepsy (mean age ± standard deviation [SD], 9.2 ± 2.1 years) and 15 age- and sex-matched controls (mean age ± SD, 9.8 ± 1.8 years) underwent neuropsychological assessment and a magnetic resonance imaging (MRI) examination. T2 relaxometry scans were used to distinguish myelin-water from tissue water and to determine the myelin-water fraction (MWF) in the frontal, temporal, parietal, occipital, and insular lobes. A linear regression model including age and sex as covariates was used to investigate group differences. Furthermore, the relationship of MWF with cognitive performance and epilepsy characteristics was determined.

RESULTS

The frontal lobe revealed a significantly lower myelin-water content in children with CAE compared to controls over the developmental age range of 6-12 years (5.7 ± 1.0% vs 6.6 ± 1.1%, P = 0.02). This association was not found for any of the other four lobes (P > 0.10). No significant relation was found between myelin-water content and cognitive performance or epilepsy characteristics.

SIGNIFICANCE

The lower frontal myelin-water content of children with CAE in comparison with healthy controls probably reflects an altered neurodevelopmental aspect in CAE, of which the underlying mechanisms still need to be unraveled.

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.

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.

Preventing cognitive impairment in children with epilepsy

PURPOSE OF REVIEW

Cognitive impairments are common in children with epilepsy. They may already be present before the onset of epilepsy or occur - and even progress - during its course. Many variables contribute to cognitive dysfunction. Those that can be targeted to prevent (further) cognitive impairment will be highlighted in this review.

RECENT FINDINGS

Ideally, but not yet realistically, epileptogenesis is prevented to avert seizures and cognitive impairments in high-risk patients. New and targeted treatments of progressive epileptogenic disorders and precision medicine approaches in genetic epilepsies are increasingly applied. Cognitive outcome benefits from early diagnosis and treatment of epileptic encephalopathy. Ongoing seizures may cause permanent and progressive changes in brain structure and connectivity, suggesting that early seizure control optimizes eventual cognitive functioning. Frequent interictal epileptiform discharges justify treatment in children with cognitive impairments that are otherwise unexplained. Cognitive adverse effects of antiepileptic drugs should be closely monitored and balanced against potential benefits. Finally, early surgical treatment in selected candidates will improve their cognitive outcome.

SUMMARY

Although important determinants of intellectual functioning - including the child's genetic and environmental background and the epileptogenic pathology - may not be modifiable, several variables that contribute to cognitive impairment can be targeted to improve outcome. Early etiological diagnosis, personalized therapies, presurgical evaluation, and strict control of seizures - or in some patients interictal discharges - can prevent (further) cognitive impairments.

Immunotherapy by targeting of VGKC complex for seizure control and prevention of cognitive impairment in a mouse model of epilepsy

Epilepsy is a type of refractory neurologic disorder mental disease, which is associated with cognitive impairments and memory dysfunction. However, the potential mechanisms of epilepsy are not well understood. Previous evidence has identified the voltage gated potassium channel complex (VGKC) as a target in various cohorts of patients with epilepsy. In the present study, the efficacy of an antibody against VGKC (anti-VGKC) for the treatment of epilepsy in mice was investigated. A mouse model of lithium-pilocarpine temporal lobe epilepsy was established and anti-VGKC treatment was administered for 30 days. Memory impairment, anxiety, visual attention, inhibitory control and neuronal loss were measured in the mouse model of lithium-pilocarpine temporal lobe epilepsy. The results revealed that epileptic mice treated with anti-VGKC were able to learn the task and presented attention impairment, even a tendency toward impulsivity and compulsivity. It was also exhibited that anti-VGKC treatment decreased neuronal loss in structures classically associated with attentional performance in hippocampus. Mice who received Anti-VGKC treatment had inhibited motor seizures and hippocampal damage as compared with control mice. In conclusion, these results indicated that anti-VGKC treatment may present benefits for improvements of the condition of motor attention impairment and cognitive competence, which suggests that VGKC may be a potential target for the treatment of epilepsy.

Neurocognitive Comorbidities in Pediatric Epilepsy: Lessons in the Laboratory and Clinical Profile

Children with epilepsy are at risk for a variety of neurocognitive comorbidities. Animal models have increased our understanding about the neurobiological mechanisms underlying the association between seizures and these comorbidities. This article starts with an overview of the current data on animal model research, studying the influence of early-life seizures, followed by a summary of potential cellular and molecular mechanisms by which seizures can affect cognitive development. We then describe specific abnormal neuropsychological profiles that accompany specific pediatric epilepsy syndromes. Finally, we offer a potential guideline to the treatment and management of children with epilepsy and its neurocognitive comorbidities.

Early Life Epilepsies are a Comorbidity of Developmental Brain Disorders

Early-life epilepsies are a series of disorders frequently accompanied by a broad range of morbidities that include cognitive, behavioral, neuromuscular, and sleep disturbances; enteric and other forms of autonomic dysfunction; sensory processing difficulties; and other issues. Usually these morbidities cluster together in a single patient. Rather than these being separate conditions, all, including the seizures, are manifestations or coexpressions of developmental brain disorders. Instead of viewing epilepsy as the disease and the other features as comorbidities, approaching early-life epilepsies as part of the spectrum of developmental brain disorders could have implications for multidisciplinary care models, anticipatory guidance, and counseling of parents, as well as the design of randomized trials and targeting important outcomes. Ultimately, such an approach could improve understanding and help optimize outcomes in these difficult to treat disorders of early childhood.

Disrupted topological organization of structural brain networks in childhood absence epilepsy

Childhood absence epilepsy (CAE) is the most common paediatric epilepsy syndrome and is characterized by frequent and transient impairment of consciousness. In this study, we explored structural brain network alterations in CAE and their association with clinical characteristics. A whole-brain structural network was constructed for each participant based on diffusion-weighted MRI and probabilistic tractography. The topological metrics were then evaluated. For the first time, we uncovered modular topology in CAE patients that was similar to healthy controls. However, the strength, efficiency and small-world properties of the structural network in CAE were seriously damaged. At the whole brain level, decreased strength, global efficiency, local efficiency, clustering coefficient, normalized clustering coefficient and small-worldness values of the network were detected in CAE, while the values of characteristic path length and normalized characteristic path length were abnormally increased. At the regional level, especially the prominent regions of the bilateral precuneus showed reduced nodal efficiency, and the reduction of efficiency was significantly correlated with disease duration. The current results demonstrate significant alterations of structural networks in CAE patients, and the impairments tend to grow worse over time. Our findings may provide a new way to understand the pathophysiological mechanism of CAE.

Altered Effective Connectivity Network in Childhood Absence Epilepsy: A Multi-frequency MEG Study

Using multi-frequency magnetoencephalography (MEG) data, we investigated whether the effective connectivity (EC) network of patients with childhood absence epilepsy (CAE) is altered during the inter-ictal period in comparison with healthy controls. MEG data from 13 untreated CAE patients and 10 healthy controls were recorded. Correlation analysis and Granger causality analysis were used to construct an EC network at the source level in eight frequency bands. Alterations in the spatial pattern and topology of the network in CAE were investigated by comparing the patients with the controls. The network pattern was altered mainly in 1-4 Hz, showing strong connections within the frontal cortex and weak connections in the anterior-posterior pathways. The EC involving the precuneus/posterior cingulate cortex (PC/PCC) significantly decreased in low-frequency bands. In addition, the parameters of graph theory were significantly altered in several low- and high-frequency bands. CAE patients display frequency-specific abnormalities in the network pattern even during the inter-ictal period, and the frontal cortex and PC/PCC might play crucial roles in the pathophysiology of CAE. The EC network of CAE patients was over-connective and random during the inter-ictal period. This study is the first to reveal the frequency-specific alteration in the EC network during the inter-ictal period in CAE patients. Multiple-frequency MEG data are useful in investigating the pathophysiology of CAE, which can serve as new biomarkers of this disorder.

Altered degree centrality in childhood absence epilepsy: A resting-state fMRI study

Modern network studies have suggested that the pathology of many neurological diseases is in fact not equally distributed over the brain but preferentially affects the hub regions. This study aims to investigate how hub regions were affected in Children with Childhood absence epilepsy (CAE) using resting-state fMRI (rs-fMRI). As one important measures obtained from rs-fMRI, degree centrality (DC) calculates the number of direct connections between a given node and the rest of the brain within the entire connectivity matrix of the brain. In this study, twenty-five CAE children and 25 healthy controls were recruited to investigate the DC changes in CAE patients. Compared with healthy controls, children with CAE showed significantly decreased DC in default mode network (DMN, medial prefrontal cortex, posterior cingulate cortex, precuneus and middle temporal cortex) and increased DC in thalamus. Importantly, significant negative correlation between the epilepsy duration and DC was found in precuneus. Our results suggested selective and specific disruption of hub nodes, especially thalamus and the highly connected brain regions within DMN, might underlie the pathophysiological mechanism of CAE.

The Effect of Age and History of Recurrent Otitis Media on Dichotic Listening and Verbal Memory in Children

OBJECTIVES

To explore the possible effects of recurrent otitis media (ROM) in early childhood on binaural processing and verbal memory in school-aged children.

METHODS

Two hundred eleven children, including 31 children with and 180 children without a history of ROM, were examined. A dichotic digit test (DDT) and a forward and backward digit memory span test (DMST) were administered.

RESULTS

A significant difference was observed between age groups among ROM-free children. The ROM-positive group earned significantly poorer results than the ROM-free group in all measurements, except for the right DDT (rDDT) score. Furthermore, a significant correlation was found between the DDT and EA scores with both DMST scores in the ROM-free group. The correlation between the rDDT and forward DMST scores was not significant in the ROM-positive group, and no significant correlation was observed between the EA score and either DMST score.

CONCLUSIONS

Our findings support that a history of OM in early childhood based on a parental survey of children is associated with differences in DDT and DMST outcomes.

Cortical and subcortical brain alterations in Juvenile Absence Epilepsy

Despite the common assumption that genetic generalized epilepsies are characterized by a macroscopically normal brain on magnetic resonance imaging, subtle structural brain alterations have been detected by advanced neuroimaging techniques in Childhood Absence Epilepsy syndrome. We applied quantitative structural MRI analysis to a group of adolescents and adults with Juvenile Absence Epilepsy (JAE) in order to investigate micro-structural brain changes using different brain measures. We examined grey matter volumes, cortical thickness, surface areas, and subcortical volumes in 24 patients with JAE compared to 24 healthy controls; whole-brain voxel-based morphometry (VBM) and Freesurfer analyses were used. When compared to healthy controls, patients revealed both grey matter volume and surface area reduction in bilateral frontal regions, anterior cingulate, and right mesial-temporal lobe. Correlation analysis with disease duration showed that longer disease was correlated with reduced surface area in right pre- and post-central gyrus. A possible effect of valproate treatment on brain structures was excluded. Our results indicate that subtle structural brain changes are detectable in JAE and are mainly located in anterior nodes of regions known to be crucial for awareness, attention and memory.