Epilepsy, cognition, and behavior: The clinical picture

Early-Life Epilepsies and the Emerging Role of Genetic Testing

IMPORTANCE

Early-life epilepsies are often a consequence of numerous neurodevelopmental disorders, most of which are proving to have genetic origins. The role of genetic testing in the initial evaluation of these epilepsies is not established.

OBJECTIVE

To provide a contemporary account of the patterns of use and diagnostic yield of genetic testing for early-life epilepsies.

DESIGN, SETTING, AND PARTICIPANTS

In this prospective cohort, children with newly diagnosed epilepsy with an onset at less than 3 years of age were recruited from March 1, 2012, to April 30, 2015, from 17 US pediatric hospitals and followed up for 1 year. Of 795 families approached, 775 agreed to participate. Clinical diagnosis of the etiology of epilepsy were characterized based on information available before genetic testing was performed. Added contributions of cytogenetic and gene sequencing investigations were determined.

EXPOSURES

Genetic diagnostic testing.

MAIN OUTCOMES AND MEASURES

Laboratory-confirmed pathogenic variant.

RESULTS

Of the 775 patients in the study (367 girls and 408 boys; median age of onset, 7.5 months [interquartile range, 4.2-16.5 months]), 95 (12.3%) had acquired brain injuries. Of the remaining 680 patients, 327 (48.1%) underwent various forms of genetic testing, which identified pathogenic variants in 132 of 327 children (40.4%; 95% CI, 37%-44%): 26 of 59 (44.1%) with karyotyping, 32 of 188 (17.0%) with microarrays, 31 of 114 (27.2%) with epilepsy panels, 11 of 33 (33.3%) with whole exomes, 4 of 20 (20.0%) with mitochondrial panels, and 28 of 94 (29.8%) with other tests. Forty-four variants were identified before initial epilepsy presentation. Apart from dysmorphic syndromes, pathogenic yields were highest for children with tuberous sclerosis complex (9 of 11 [81.8%]), metabolic diseases (11 of 14 [78.6%]), and brain malformations (20 of 61 [32.8%]). A total of 180 of 446 children (40.4%), whose etiology would have remained unknown without genetic testing, underwent some testing. Pathogenic variants were identified in 48 of 180 children (26.7%; 95% CI, 18%-34%). Diagnostic yields were greater than 15% regardless of delay, spasms, and young age. Yields were greater for epilepsy panels (28 of 96 [29.2%]; P < .001) and whole exomes (5 of 18 [27.8%]; P = .02) than for chromosomal microarray (8 of 101 [7.9%]).

CONCLUSIONS AND RELEVANCE

Genetic investigations, particularly broad sequencing methods, have high diagnostic yields in newly diagnosed early-life epilepsies regardless of key clinical features. Thorough genetic investigation emphasizing sequencing tests should be incorporated into the initial evaluation of newly presenting early-life epilepsies and not just reserved for those with severe presentations and poor outcomes.

Ginkgo biloba L. attenuates spontaneous recurrent seizures and associated neurological conditions in lithium-pilocarpine rat model of temporal lobe epilepsy through inhibition of mammalian target of rapamycin pathway hyperactivation

ETHNOPHARMACOLOGICAL RELEVANCE

Ginkgo biloba L. (Ginkgoaceae) has been widely used in traditional medicine for variety of neurological conditions particularly behavioral and memory impairments.

AIM OF THE STUDY

The present study was envisaged to explore the effect of a standardized fraction of Ginkgo biloba leaves (GBbf) in rat model of lithium-pilocarpine induced spontaneous recurrent seizures, and associated behavioral impairments and cognitive deficit.

MATERIALS AND METHODS

Rats showing appearance of spontaneous recurrent seizures following lithium pilocarpine (LiPc)-induced status epilepticus (SE) were treated with different doses of GBbf or vehicle for subsequent 4 weeks. The severity of seizures and aggression in rats were scored following treatment with GBbf. Further, open field, forced swim, novel object recognition and Morris water maze tests were conducted. Histopathological, protein levels and gene expression studies were performed in the isolated brains.

RESULTS

Treatment with GBbf reduced seizure severity score and aggression in epileptic animals. Improved spatial cognitive functions and recognition memory, along with reduction in anxiety-like behavior were also observed in the treated animals. Histopathological examination by Nissl staining showed reduction in neuronal damage in the hippocampal pyramidal layer. The dentate gyrus and Cornu Ammonis 3 regions of the hippocampus showed reduction in mossy fiber sprouting. GBbf treatment attenuated ribosomal S6 and pS6 proteins, and hippocampal mTOR, Rps6 and Rps6kb1 mRNA levels.

CONCLUSIONS

The results of present study concluded that GBbf treatment suppressed lithium-pilocarpine induced spontaneous recurrent seizures severity and incidence with improved cognitive functions, reduced anxiety-like behavior and aggression. The effect was found to be due to inhibition of mTOR pathway hyperactivation linked with recurrent seizures.

The Impact of Electrographic Seizures on Developing Hippocampal Dendrites Is Calcineurin Dependent

Neurobehavioral abnormalities are commonly associated with intractable childhood epilepsy. Studies from numerous labs have demonstrated cognitive and socialization deficits in rats and mice that have experienced early-life seizures. However, the cellular and molecular mechanisms underlying these effects are unknown. Previously, experiments have shown that recurrent seizures in infancy suppress the growth of hippocampal dendrites at the same time they impair learning and memory. Experiments in slice cultures have also demonstrated dendrite growth suppression. Here, we crossed calcineurin B1 (CaNB1) floxed and Thy1GFP-M mice to produce mice that were homozygous for the both the floxed CaNB1 and the Thy1GFP-M transgene. Littermates that were homozygous for wild-type CaNB1 and Thy1GFP-M served as controls. Hippocampal slice cultures from these mice were transfected with an AAV/hSyn-mCherry-Cre virus to eliminate CaNB1 from neurons. Immunohistochemical results showed that CaNB1 was eliminated from at least 90% of the transfected CA1 pyramidal cells. Moreover, the CaN-dependent nuclear translocation of the CREB transcription coactivator, CREB-regulated transcriptional coactivator 1 (CRTC1), was blocked in transfected neurons. Cell attach patch recordings combined with live multiphoton imaging demonstrated that the loss of CaNB1 did not prevent neurons from fully participating in electrographic seizure activity. Finally, dendrite reconstruction showed that the elimination of CaNB1 prevented seizure-induced decreases in both dendrite length and branch number. Results suggest that CaN plays a key role in seizure-induced dendrite growth suppression and may contribute to the neurobehavioral comorbidities of childhood epilepsy.

Enduring Memory Impairments Provoked by Developmental Febrile Seizures Are Mediated by Functional and Structural Effects of Neuronal Restrictive Silencing Factor

In a subset of children experiencing prolonged febrile seizures (FSs), the most common type of childhood seizures, cognitive outcomes are compromised. However, the underlying mechanisms are unknown. Here we identified significant, enduring spatial memory problems in male rats following experimental prolonged FS (febrile status epilepticus; eFSE). Remarkably, these deficits were abolished by transient, post hoc interference with the chromatin binding of the transcriptional repressor neuron restrictive silencing factor (NRSF or REST). This transcriptional regulator is known to contribute to neuronal differentiation during development and to programmed gene expression in mature neurons. The mechanisms of the eFSE-provoked memory problems involved complex disruption of memory-related hippocampal oscillations recorded from CA1, likely resulting in part from impairments of dendritic filtering of cortical inputs as well as abnormal synaptic function. Accordingly, eFSE provoked region-specific dendritic loss in the hippocampus, and aberrant generation of excitatory synapses in dentate gyrus granule cells. Blocking NRSF transiently after eFSE prevented granule cell dysmaturation, restored a functional balance of γ-band network oscillations, and allowed treated eFSE rats to encode and retrieve spatial memories. Together, these studies provide novel insights into developing networks that underlie memory, the mechanisms by which early-life seizures influence them, and the means to abrogate the ensuing cognitive problems.SIGNIFICANCE STATEMENT Whereas seizures have been the central focus of epilepsy research, they are commonly accompanied by cognitive problems, including memory impairments that contribute to poor quality of life. These deficits often arise before the onset of spontaneous seizures, or independent from them, yet the mechanisms involved are unclear. Here, using a rodent model of common developmental seizures that provoke epilepsy in a subset of individuals, we identify serious consequent memory problems. We uncover molecular, cellular, and circuit-level mechanisms that underlie these deficits and successfully abolish them by targeted therapeutic interventions. These findings may be important for understanding and preventing cognitive problems in individuals suffering long febrile seizures.

The Contribution of Cognitive Networks to Depression in Epilepsy

This review poses the question: Does disruption to cognitive brain networks in epilepsy contribute to the problem of comorbid depression? Initial evidence suggests that the network disease that gives rise to seizures has a predilection for the same cognition-related networks that regulate mood, with comorbidity reflective of more extensive disease. Framing both epilepsy and its psychiatric comorbidities in terms of dysfunction in overlapping (cognitive) networks raises the possibility that depression can be a primary feature of the disease in some cases and facilitates an epilepsy classification system where behavioral features of the disorder are embedded in a neurobiological mechanism.

Behavioral disinhibition and antiepileptic treatment in childhood epilepsy: A retrospective cohort study

OBJECTIVE

To test whether specific classes of antiepileptic drugs increase the risk for behavioral disinhibition, a frequent complication of treatment of childhood epilepsy.

METHODS

In a sample of children with active epilepsy and antiepileptic drug (AED) treatment (n = 146, age 4-17 years), we performed a retrospective chart analysis of the occurrence of symptoms indicating reduced behavioral disinhibition following AED treatment. We used a risk-set approach to analyze whether the presence or recent addition of AED categories defined by their mechanism of action were associated with enhanced risk for behavioral disinhibition symptoms.

RESULTS

Mean duration of follow-up was 2,343 days (range 218-6,292, standard deviation [SD] 1,437). Episodes of behavioral disinhibition were reported in 51 (34.9%) children, with variable latencies between latest change and occurrence of behavioral disinhibition symptoms (mean 67 days, range 2-367). Current use of AEDs targeting gamma-aminobutyric acid (GABA) (odds ratio [OR] 1.8, 95% confidence interval [CI] 1.02-3.29, p = 0.04) and SV2A-mediated neurotransmitter release (SV2A)-mediated (2.0, 1.13-3.60, p = 0.02) neurotransmitter release was associated with increased risk for behavioral disinhibition. Restricting the analysis to the 90 days before behavioral disinhibition episode occurrence revealed that only addition of GABAergic AEDs (OR = 26.88, 95% CI = 6.71-107.76, p < 0.001) was associated with behavioral disinhibition. In contrast to our expectations, seizure control was reported to have improved parallel to most behavioral disinhibition episodes.

SIGNIFICANCE

This exploration of behavioral disinhibition in relation to antiepileptic drug treatment indicates that GABA potentiating drugs are specifically associated with behavioral problems during treatment of childhood epilepsy. Behavioral disinhibition episodes often occurred while seizure control improved, which may have reduced alertness for the consequences of AEDs on interictal symptoms. Our findings may be related to the increasing evidence for a role for excitatory actions of GABA in childhood epilepsy.

Etiology, syndrome diagnosis, and cognition in childhood-onset epilepsy: A population-based study

Objective

To evaluate the prevalence of various etiologies of epilepsies and epilepsy syndromes and to estimate cognitive function in cases of childhood‐onset epilepsy.

Methods

A population‐based retrospective registry study. We identified all medically treated children with epilepsy born in 1989–2007 in Finland's Kuopio University Hospital catchment area, combining data from the birth registry and the national registry of special‐reimbursement medicines. We reevaluated the epilepsy diagnoses and syndromes and gathered data on etiologies and cognitive impairment.

Results

We identified 289 children with epilepsy. The annual incidence rate of epilepsies and epilepsy syndromes was 38 in 100,000, and the misdiagnosis rate was 3%. A specific etiology was identified in 65% of the cases, with a structural etiology accounting for 29% and a genetic or presumed genetic etiology for 32%. Most patients with unknown‐etiology epilepsy had focal epilepsy and were of normal intelligence. Intellectual disability was detected in 35% of cases, and only 17% in this group had an unknown etiology for the epilepsy. Electroclinical syndromes (mainly West syndrome) were recognized in 35% of the patients.

Significance

Epilepsy is a complex disease that encompasses many etiologies and rare syndromes. The etiology and specific epilepsy syndrome are important determinants of the outcome and key factors in treatment selection. Etiological diagnosis can be achieved for the majority of children and syndromic diagnosis for only a third.

Early-life status epilepticus induces long-term deficits in anxiety and spatial learning in mice

Background

One of the most devastating aspects of developmental epilepsy is the long-term impact on behavior. Children with epilepsy show a high co-morbidity with anxiety disorders and autism.

Methods

To examine whether early-life status epilepticus results in altered anxiety, repetitive behavior, social behavior, and learning and memory, we induced status epilepticus in male C57BL/6 mice on postnatal day (PD) 10. The mice received intraperitoneal injections of either kainic acid (2mg/kg) or 0.9% normal saline. We also included a nontreated control group. Kainic acid induced status epilepticus for approximately 1.5 hrs. At PD60, the adult mice were then tested in a battery of behavioral tasks, including open field activity, elevated-plus maze, light-dark test, marble burying, social chamber, social partition, conditioned fear, novel object recognition, and Morris water maze.

Results

The early-life seizure group showed consistent increases in anxiety in the open field test (p < 0.05), elevated plus maze (p < 0.05), and light-dark task (p < 0.01). The seizure group showed significant (p < 0.01) impairment in the Morris water maze. There were no differences observed in marble burying, social partition, social chamber, novel object recognition, or delay fear conditioning tasks.

Conclusions

These results demonstrate that a single insult of status epilepticus during the neonatal period is sufficient to cause specific, long-term impairments in anxiety and spatial learning.

Behavioral health in young adults with epilepsy: Implications for transition of care

AIM

Neurodevelopmental and behavioral health disorders commonly occur with epilepsy, yet risk for young adults is unknown. The aim of this study was to determine the distribution and risk characteristics of neurodevelopmental and behavior health comorbidities among young adults with epilepsy compared with those among young adults with migraine and healthy controls.

METHOD

A case-control study examining hospital admission, outpatient, and emergency department (ED) visits for young adults with an ICD-9-CM diagnosis of epilepsy, migraine, or lower extremity fracture (LEF) was conducted. The association of epilepsy, migraine, or LEF with comorbidities was evaluated with univariate and multivariate polytomous logistic regression.

RESULTS

From 2000 to 2013, 29,139 young adults ages 19 to 25years were seen in hospitals and EDs for epilepsy (5666), migraine (17,507), or LEF (5966). Young adults with epilepsy had higher proportions of behavioral health comorbidities (51.8%) compared with controls with migraine (37.6%) or LEF (21.6%). In young adults with epilepsy compared with migraine, the increased risk of having any behavioral health comorbidity was 76%, and neurodevelopmental comorbidity was 297%. After adjustment, young adults with epilepsy showed significantly higher odds of each behavioral health comorbidity compared with controls with migraine and LEF.

INTERPRETATION

Young adults with epilepsy are particularly susceptible to behavioral health and neurodevelopmental disorders. Results are discussed within the context of transition to adult care.

Commonly prescribed drugs associate with cognitive function: a cross-sectional study in UK Biobank

OBJECTIVE

To investigate medications associated with cognitive function.

DESIGN

Population-based cross-sectional cohort study.

SETTING

UK Biobank.

PARTICIPANTS

UK Biobank participants aged 37-73 years who completed cognitive tests at the baseline visit in 2006-2010.

MAIN OUTCOME MEASURES

Cognitive test outcomes on verbal-numerical reasoning test (n=165 493), memory test (n=482 766) and reaction time test (n=496 813).

RESULTS

Most drugs (262 of 368) were not associated with any cognitive tests after adjusting for age, gender, education, household income, smoking, alcohol status, psychostimulant/nootropic medication use, assessment centre, and concurrent diagnoses and medications. Drugs used for nervous system disorders were associated with poorer cognitive performance (antiepileptics, eg, topiramate breasoning(score) -0.65 (95% CI -1.05 to -0.24), bmemory(score) -1.41 (-1.79 to -1.04); antipsychotics, eg, risperidone breaction time(ms) -33 (-46 to -20), negative values indicate poor cognitive performance and vice versa). Drugs used for non-nervous system conditions also showed significant negative association with cognitive score, including those where such an association might have been predicted (antihypertensives, eg, amlodipine breasoning -0.1 (-0.15 to -0.06), bmemory -0.08 (-0.13 to -0.03), breaction time -3 (-5 to -2); antidiabetics, eg, insulin breaction time -13 (-17 to -10)) and others where such an association was a surprising observation (proton pump inhibitors, eg, omeprazole breasoning -0.11 (-0.15 to -0.06), bmemory -0.08 (-0.12 to -0.04), breaction time -5 (-6 to -3); laxatives, eg, contact laxatives breaction time -13 (-19 to -8)). Finally, only a few medications and health supplements showed association towards a positive effect on cognitive function (anti-inflammatory agents, eg, ibuprofen breasoning 0.05 (0.02 to 0.08), breaction time 4 (3, 5); glucosamine breasoning 0.09 (0.03 to 0.14), breaction time 5 (3 to 6)).

CONCLUSIONS

In this large volunteer study, some commonly prescribed medications were associated with poor cognitive performance. Some associations may reflect underlying diseases for which the medications were prescribed, although the analysis controlled for the possible effect of diagnosis. Other drugs, whose association cannot be linked to the effect of any disease, may need vigilance for their implications in clinical practice.

Reprint of: The new approach to classification: Rethinking cognition and behavior in epilepsy

There has been considerable debate surrounding the benefits and drawbacks of the new approach to classifying the epilepsies released by the ILAE Commission on Classification and Terminology (2005-2009). This new approach has significant implications for the way we conceptualize and assess cognition and behavior in epilepsy; however, as yet, there has been limited discussion of these issues in the field. The purpose of this Targeted Review is to spark this discussion by encouraging researchers and clinicians to think about the changes that the new approach may bring. These may include (i) reframing the way we think about the comorbidities of epilepsy, (ii) more precisely characterizing the cognitive and behavioral phenotypes of electroclinical syndromes, (iii) more carefully mapping the longitudinal trajectory of cognitive and behavioral features relative to the timing of seizures, and (iv) considering the links between cognitive, behavioral, and neurological phenotypes in the new classification scheme. It is hoped that such changes will aid translation of the advances in cognitive and behavioral neuroscience into routine clinical practice by providing purer markers of disease and more targeted treatments. A Special Issue canvassing such issues will be forthcoming that will consider current knowledge of the cognitive and behavioral features of the epilepsies from the view of the new classification scheme.

The new approach to classification of focal epilepsies: Epileptic discharge and disconnectivity in relation to cognition

The new classification of epilepsy stratifies the disease into an acute level, based on seizures, and an overarching chronic level of epileptic syndromes (Berg et al., 2010). In this new approach, seizures are considered either to originate and evolve in unilateral networks or to rapidly encompass both hemispheres. This concept extends the former vision of focal and generalized epilepsies to a genuine pathology of underlying networks. These key aspects of the new classification can be linked to the concept of cognitive curtailing in focal epilepsy. The present review will discuss the conceptual implications for acute and chronic cognitive deficits with special emphasis on transient and structural disconnectivity. Acute transient disruption of brain function is the hallmark of focal seizures. Beyond seizures, however, interictal epileptic discharges (IEDs) are increasingly recognized to interfere with physiological brain circuitry. Both concomitant EEG and high-precision neuropsychological testing are necessary to detect these subtle effects, which may concern task-specific or default-mode networks. More recent data suggest that longstanding IEDs may affect brain maturation and eventually be considered as a biomarker of pathological wiring. This brings us to the overarching level of chronic cognitive and behavioral comorbidity. We will discuss alterations in structural connectivity measured with diffusion-weighted imaging and tractography. Among focal epilepsies, much of our current insights are derived from temporal lobe epilepsy and its impact on neuropsychological and psychiatric functioning. Structural disconnectivity is maximal in the temporal lobe but also concerns widespread language circuitry. Eventually, pathological wiring may contribute to the clinical picture of cognitive dysfunction. We conclude with the extrapolation of these concepts to current research topics and to the necessity of establishing individual patient profiles of network pathology with EEG, high-precision neuropsychological testing, and state-of-the-art neuroimaging. This article is part of a Special Issue entitled "The new approach to classification: Rethinking cognition and behavior in epilepsy".

Interictal epileptiform discharges have an independent association with cognitive impairment in children with lesional epilepsy

OBJECTIVES

The relative contribution of interictal epileptiform discharges (IEDs) to cognitive dysfunction in comparison with the underlying brain pathology is not yet understood in children with lesional focal epilepsy.

METHODS

The current study investigated the association of IEDs with intellectual functioning in 103 children with medication-resistant focal epilepsy. Hierarchical multiple regression analyses were used to determine the independent contribution of IED features on intellectual functioning, after controlling for effects of lesional pathology, epilepsy duration, and medication. Exploratory analyses were conducted for language and memory scores as well as academic skills available in a subset of participants.

RESULTS

The results reveal that IEDs have a negative association with IQ with independent, additive effects documented for frequent and bilaterally distributed IEDs as well as discharge enhancement in sleep. Left-lateralized IEDs had a prominent effect on verbal intelligence, in excess of the influence of left-sided brain pathology. These effects extended to other cognitive functions, most prominently for sleep-enhanced IEDs to be associated with deficits in expressive and receptive language, reading, spelling and numerical skills.

SIGNIFICANCE

Overall, IED effects on cognition were of a magnitude similar to lesional influences or drug effects (topiramate use). This study demonstrates an association between IEDs and cognitive dysfunction, independent of the underlying focal brain pathology.

Sleep-dependent memory consolidation in the epilepsy monitoring unit: A pilot study

OBJECTIVE

We sought to examine whether patients with focal epilepsy exhibit sleep dependent memory consolidation, whether memory retention rates correlated with particular aspects of sleep physiology, and how the process was affected by seizures.

METHODS

We prospectively recruited patients with focal epilepsy and assessed declarative memory using a task consisting of 15 pairs of colored pictures on a 5×6 grid. Patients were tested 12h after training, once after 12h of wakefulness and once after 12h that included sleep. EMG chin electrodes were placed to enable sleep scoring. The number and density of sleep spindles were assessed using a wavelet-based algorithm.

RESULTS

Eleven patients were analyzed age 21-56years. The percentage memory retention over 12h of wakefulness was 62.7% and over 12h which included sleep 83.6% (p=0.04). Performance on overnight testing correlated with the duration of slow wave sleep (SWS) (r=+0.63, p<0.05). Three patients had seizures during the day, and 3 had nocturnal seizures. Day-time seizures did not affect retention rates, while those patients who had night time seizures had a drop in retention from an average of 92% to 60.5%.

CONCLUSIONS

There is evidence of sleep dependent memory consolidation in patients with epilepsy which mostly correlates with the amount of SWS. Our preliminary findings suggest that nocturnal seizures likely disrupt sleep dependent memory consolidation.

SIGNIFICANCE

Findings highlight the importance of SWS in sleep dependent memory consolidation and the adverse impact of nocturnal seizures on this process.

Clinical characteristics of patients with epilepsy in a specialist neuropsychiatry service

Neuropsychiatry services provide specialist input into the assessment and management of behavioral symptoms associated with a range of neurological conditions, including epilepsy. Despite the centrality of epilepsy to neuropsychiatry and the recent expansion of neuropsychiatry service provision, little is known about the clinical characteristics of patients with epilepsy who are routinely seen by a specialist neuropsychiatry service. This retrospective study filled this gap by retrospectively evaluating a naturalistic series of 60 consecutive patients with epilepsy referred to and assessed within a neuropsychiatry setting. Fifty-two patients (86.7%) had active epilepsy and were under the ongoing care of the referring neurologist for seizure management. The majority of patients (N=42; 70.0%) had a diagnosis of localization-related epilepsy, with temporal lobe epilepsy as the most common epilepsy type (N=37; 61.7%). Following clinical assessment, 39 patients (65.0%) fulfilled formal diagnostic criteria for at least one psychiatric disorder; nonepileptic attack disorder (N=37; 61.7%), major depression (N=23; 38.3%), and generalized anxiety disorder (N=16; 26.7%) were the most commonly diagnosed comorbidities. The clinical characteristics of patients seen in specialist neuropsychiatry settings are in line with the results from previous studies in neurology clinics in terms of both epilepsy and psychiatric comorbidity. Our findings confirm the need for the development and implementation of structured care pathways for the neuropsychiatric aspects of epilepsy, with focus on comorbid nonepileptic attacks and affective and anxiety symptoms. This is of particular importance in consideration of the impact of behavioral symptoms on patients' health-related quality of life.

Health resource utilization varies by comorbidities in children with epilepsy

OBJECTIVES

Comorbidities in adults with epilepsy have been shown to significantly increase health resource utilization (HRU). The current study aimed to determine whether a similar association exists among children with epilepsy in a universal health insurance system.

METHODS

Health administrative databases in Ontario, Canada were used to evaluate the frequency of neurologist visits, emergency department (ED) visits, and hospitalizations. We evaluated the association between HRU and comorbidities, including depression, anxiety, learning disability, attention deficit hyperactivity disorder (ADHD), and autistic spectrum disorder (ASD), adjusting for age, sex, residence, and socio-economic status.

RESULTS

The frequency of neurology visits was increased by comorbid depression, ASD, and learning disability (adjusted relative risk [aRR]=1.29-2.07; p<.01). The frequency of ED visits was increased by all comorbidities (aRR=1.26-2.83; p<.0001). The frequency of hospitalizations was increased by comorbid depression, anxiety, ASD, and learning disability (aRR=1.77-7.20; p<.0001). Learning disability had the largest impact on HRU. For each additional comorbidity, the frequency of neurology visits, ED visits, and hospitalizations increased by 1.64 to 3.16 times (p<.0001).

CONCLUSIONS

Among children with epilepsy, mental health and developmental comorbidities were associated with increased HRU, and different comorbidities influenced different types of HRU. In addition, we highlight the importance of identifying and managing these comorbidities, as they increased the risks of costly HRU such as ED visits and hospitalizations.

NRSF and BDNF polymorphisms as biomarkers of cognitive dysfunction in adults with newly diagnosed epilepsy

Cognitive dysfunction is a common comorbidity in people with epilepsy, but its causes remain unclear. It may be related to the etiology of the disorder, the consequences of seizures, or the effects of antiepileptic drug treatment. Genetics may also play a contributory role. We investigated the influence of variants in the genes encoding neuron-restrictive silencer factor (NRSF) and brain-derived neurotrophic factor (BDNF), proteins previously associated with cognition and epilepsy, on cognitive function in people with newly diagnosed epilepsy. A total of 82 patients who had previously undergone detailed neuropsychological assessment were genotyped for single nucleotide polymorphisms (SNPs) across the NRSF and BDNF genes. Putatively functional SNPs were included in a genetic association analysis with specific cognitive domains, including memory, psychomotor speed, and information processing. Cross-sectional and longitudinal designs were used to explore genetic influences on baseline cognition at diagnosis and change from baseline over the first year since diagnosis, respectively. We found a statistically significant association between genotypic variation and memory function at both baseline (NRSF: rs1105434, rs2227902 and BDNF: rs1491850, rs2030324, rs11030094) and in our longitudinal analysis (NRSF: rs2227902 and BDNF: rs12273363). Psychomotor speed was also associated with genotype (NRSF rs3796529) in the longitudinal assessment. In line with our previous work on general cognitive function in the healthy aging population, we observed an additive interaction between risk alleles for the NRSF rs2227902 (G) and BDNF rs6265 (A) polymorphisms which was again consistent with a significantly greater decline in delayed recall over the first year since diagnosis. These findings support a role for the NRSF-BDNF pathway in the modulation of cognitive function in patients with newly diagnosed epilepsy.

Gene Mutation Analysis in 253 Chinese Children with Unexplained Epilepsy and Intellectual/Developmental Disabilities

Objective

Epilepsy and intellectual/developmental disabilities (ID/DD) have a high rate of co-occurrence. Here, we investigated gene mutations in Chinese children with unexplained epilepsy and ID/DD.

Methods

We used targeted next-generation sequencing to detect mutations within 300 genes related to epilepsy and ID/DD in 253 Chinese children with unexplained epilepsy and ID/DD. A series of filtering criteria was used to find the possible pathogenic variations. Validation and parental origin analyses were performed by Sanger sequencing. We reviewed the phenotypes of patients with each mutated gene.

Results

We identified 32 novel and 16 reported mutations within 24 genes in 46 patients. The detection rate was 18% (46/253) in the whole group and 26% (17/65) in the early-onset (before three months after birth) epilepsy group. To our knowledge, we are the first to report KCNAB1 is a disease-causing gene of epilepsy by identifying a novel de novo mutation (c.1062dupCA p.Leu355HisfsTer5) within this gene in one patient with early infantile epileptic encephalopathy (EIEE). Patients with an SCN1A mutation accounted for the largest proportion, 17% (8/46). A total of 38% (9/24) of the mutated genes re-occurred at least 2 times and 63% (15/24) occurred only one time. Ion channel genes are the most common (8/24) and genes related to synapse are the next most common to occur (5/24).

Significance

We have established genetic diagnosis for 46 patients of our cohort. Early-onset epilepsy had the highest detection rate. KCNAB1 mutation was first identified in EIEE patient. We expanded the phenotype and mutation spectrum of the genes we identified. The mutated genes in this cohort are mostly isolated. This suggests that epilepsy and ID/DD phenotypes occur as a consequence of brain dysfunction caused by a highly diverse population of mutated genes. Ion channel genes and genes related to synapse were more common mutated in this patient cohort.

Psychometric validation of the Pediatric Symptom Checklist-17 in a pediatric population with epilepsy: A methods study

OBJECTIVE

The purpose of this study was to address critical gaps in behavioral health care of youth with epilepsy by examining the utility of a brief, well-validated screening instrument, the PSC-17, in a pediatric population with epilepsy.

METHOD

One hundred eighty-seven caregivers of youth with epilepsy ages 2-17years completed the PSC-17 for their child/adolescent during a routine epilepsy visit. Demographic and seizure information was abstracted from electronic medical record review.

RESULTS

Confirmatory factor analyses for the PSC-17 revealed an acceptable fit with the 3-factor model, χ(2) (116 [N=187]=204.54, p<0.001, CFI=0.90, TLI=0.88, RMSEA=0.064, SRMSR=0.078). Scale level reliabilities were excellent (0.72-0.85). Interscale correlations were moderate (0.48-0.69). Approximately 1/5th of the sample met clinical cut-offs for the total score of behavioral health concerns. However, an additional 20% of the sample had at least one elevated subscale score despite the total score being in the normative/nonclinical range.

SIGNIFICANCE

The PSC-17 is a brief, free behavioral health screening tool with adequate to strong validity, reliability, and clinical utility for pediatric populations with epilepsy. Clinicians should consider using the 3 PSC-17 subscale scores instead of the total score to guide referrals for further evaluation as the subscales may provide a more accurate picture of functioning in particular domains.

Third International Congress on Epilepsy, Brain, and Mind: Part 2

Epilepsy is both a disease of the brain and the mind. Here, we present the second of two papers with extended summaries of selected presentations of the Third International Congress on Epilepsy, Brain and Mind (April 3-5, 2014; Brno, Czech Republic). Humanistic, biologic, and therapeutic aspects of epilepsy, particularly those related to the mind, were discussed. The extended summaries provide current overviews of epilepsy, cognitive impairment, and treatment, including brain functional connectivity and functional organization; juvenile myoclonic epilepsy; cognitive problems in newly diagnosed epilepsy; SUDEP including studies on prevention and involvement of the serotoninergic system; aggression and antiepileptic drugs; body, mind, and brain, including pain, orientation, the "self-location", Gourmand syndrome, and obesity; euphoria, obsessions, and compulsions; and circumstantiality and psychiatric comorbidities.

Paroxysmal phenomena in severe disabled children with refractory seizures. From clinical to long-video-EEG processing data to re-examine suspect events

To provide an estimate of the occurrence of misdiagnosis in paroxysmal events in institutionalized children with severe disabilities and refractory epilepsy. A multi-step diagnostic survey, from observational to long-term video-EEG monitoring was performed in 46 severe disabled children. Multirater Kappa statistic was used to assess agreement between investigators and to individualize children who remained with dubious events. Subsequently, prolonged EEG-video monitoring analysis was performed in selected children to define phenomena due to seizures. A total of 128 video records were performed, 64 routine video-EEG and 27 long-monitoring video-EEG data were screened for detailed analysis. Thirty (21 female, 9 male) children (65%) with dubious seizures were identified by video records (concordance K=0.63). Of these, in 18 children (39%) seizures were excluded by routine video-EEG monitoring (K=0.86). Twelve children (26%) required accurate investigations with long-term video-EEG. In 5 children (11%), 3 symptomatic and 2 cryptogenic, very short and subtle seizures were confirmed by investigators concordance (K=0.83). Distinguishing paroxysmal phenomena is a challenge in children with severe disabilities; its most remarkable consequence is inappropriate pharmacological treatment and social costs. Our data suggest that the frequency of misdiagnosis could have been underestimated. The clinicians who manage children with severe disabilities and refractory epilepsy must remain alert to risk of an incorrect treatment.

Neurodevelopmental and mental health comorbidities in children and adolescents with epilepsy and migraine: a response to identified research gaps

AIM

To determine the distribution and risk characteristics of comorbid neurodevelopmental and mental health comorbidities among children and adolescents (6-18y) with epilepsy or migraine (i.e. a neurological condition with shared features and potential etiology) compared with lower extremity fracture (LEF).

METHOD

This case-control study involved a subset analysis of surveillance data in South Carolina, USA. Hospital admission, outpatient, and emergency department visits for individuals with an International Classification of Disease, 9th revision Clinical Modification diagnosis of epilepsy (n=6730; 54.5% females, 45.5% males; mean age [SD] 14y 2mo [4y 5mo]); migraine (n=10 495; 74.5% females, 25.5% males; 15y 6mo [2y 6mo]), or LEF (n=15 305; 40.3% females, 59.7% males; 13y 11mo [2y 11mo]) from January 1 2000 to December 31 2011 were identified. The association of epilepsy, migraine, or LEF with any mental health comorbidity was evaluated with univariate and multivariate polytomous logistic regression.

RESULTS

Comorbidities were highly prevalent in children and adolescents, with epilepsy with a rate of 29.7% (95% confidence interval [CI]: 28.6-30.8) for mental health comorbidities and 30.8% (95% CI: 29.7-31.9) for neurodevelopmental comorbidities. The odds of mental health comorbidity was 2.20 (95% CI: 2.02-2.39) for children and adolescents with epilepsy and 1.60 (95% CI: 1.48-1.73) for migraine, in reference to children and adolescents with LEF after adjusting for potential confounders. Prevalence and risk for specific comorbidities are presented.

INTERPRETATION

Neuropathophysiological and psychosocial factors specific to epilepsy may provide more risk for adolescents with epilepsy compared to migraine.

The new approach to classification: rethinking cognition and behavior in epilepsy

There has been considerable debate surrounding the benefits and drawbacks of the new approach to classifying the epilepsies released by the ILAE Commission on Classification and Terminology (2005-2009). This new approach has significant implications for the way we conceptualize and assess cognition and behavior in epilepsy; however, as yet, there has been limited discussion of these issues in the field. The purpose of this Targeted Review is to spark this discussion by encouraging researchers and clinicians to think about the changes that the new approach may bring. These may include (i) reframing the way we think about the comorbidities of epilepsy, (ii) more precisely characterizing the cognitive and behavioral phenotypes of electroclinical syndromes, (iii) more carefully mapping the longitudinal trajectory of cognitive and behavioral features relative to the timing of seizures, and (iv) considering the links between cognitive, behavioral, and neurological phenotypes in the new classification scheme. It is hoped that such changes will aid translation of the advances in cognitive and behavioral neuroscience into routine clinical practice by providing purer markers of disease and more targeted treatments. A Special Issue canvassing such issues will be forthcoming that will consider current knowledge of the cognitive and behavioral features of the epilepsies from the view of the new classification scheme.

Kainate-induced epileptogenesis alters circular hole board learning strategy but not the performance of C57BL/6J mice

Patients with mesial temporal lobe epilepsy (mTLE) frequently show cognitive deficits. However, the relation between mTLE and cognitive impairment is poorly understood. To gain more insight into epilepsy-associated alterations in cognitive performance, we studied the spatial learning of C57BL/6J mice five weeks after kainate-induced status epilepticus (SE). Typically, structural hippocampal rearrangements take place within five weeks after SE. Mice were monitored by exposing them to four tasks with a focus on spatial memory and anxiety: the circular hole board, modified hole board, novel object-placement task, and elevated plus maze. On the circular hole board, animals showed a higher preference for hippocampus-independent strategies after SE. In contrast, no change in strategy was seen on the modified hole board, but animals with SE were able to finish the task more often. Animals did not have an increased preference for a relocated object in the novel object-placement task but showed an increased locomotion after SE. No indications for altered anxiety were found when tested on the elevated plus maze following SE. These data suggest that the circular hole board is a well-suited paradigm to detect subtle SE-induced hippocampal deficits.

Cognitive impairment predicts social disability in persons with epilepsy

Introduction.Cognitive dysfunction is one of the main comorbidities of epilepsy which co-exists with seizures and contributes to the adverse impact of the disease on employment, education and interpersonal relationships. A fundamental question regarding cognitive dysfunction in epilepsy goes as follows: in comparison to seizures, what role does cognitive dysfunction play in causing social disability? The purpose of this review was to evaluate our understanding of the role cognitive impairment plays in social disability in persons with epilepsy (PWE). We systematically searched the medical literature and identified studies which assessed the impact of seizures and cognitive function on some aspect of social disability in PWE.

Results and Discussion.We identified 12 studies which adequately measured all variables in non-surgical cohorts, and 9 studies of cohorts following epilepsy surgery. We found evidence from non-surgical and from surgical series that cognitive variables strongly correlate with levels of social disability.

Conclusions.We conclude that efforts to better understand the origins of cognitive dysfunction in epilepsy and subsequently at developing treatment modalities will be needed in order to reduce the degree of social disability caused by the condition.

Time to focus on brain tumor-related epilepsy trials

Brain tumor-related epilepsy (BTRE) is a common complication of cerebral glioma. It has a serious impact on the patient's confidence and quality of life and can be life threatening. There are significant differences in the management of BTRE and nontumoral epilepsy in adults. Surgery is performed early in management, and resection can be curative. Radiotherapy can also improve seizure frequency. Antiepileptic drugs (AEDs) are started after first seizure but are only effective at stopping attacks in 50% of cases. There are no satisfactory randomized controlled clinical trials, or even good prospective series, to support using one AED over another with respect to efficacy. Guidelines are therefore based on poor levels of evidence. In general, the choice of AED may depend on risk of early side effect (rash, biochemical, or hematological effects) and whether drug interactions with chemotherapy are likely. In patients with suspected low-grade glioma, where use of chemotherapy early in the management is not standard practice and survival in measured in many years, the drug interactions are less relevant, and rational seizure management should focus on drugs with the fewest long-term effects on neurocognition, personality, mood, and fatigue. While intriguing and potentially very important, there is no good evidence that any specific AED has a clinical antitumor effect or improves survival. Development of special interest groups in BTRE within countries, or between countries, may be a model for promoting better BTRE trials in the future.

Matrix metalloproteinase-9 involvement in the structural plasticity of dendritic spines

Dendritic spines are the locus for excitatory synaptic transmission in the brain and thus play a major role in neuronal plasticity. The ability to alter synaptic connections includes volumetric changes in dendritic spines that are driven by scaffolds created by the extracellular matrix (ECM). Here, we review the effects of the proteolytic activity of ECM proteases in physiological and pathological structural plasticity. We use matrix metalloproteinase-9 (MMP-9) as an example of an ECM modifier that has recently emerged as a key molecule in regulating the morphology and dysmorphology of dendritic spines that underlie synaptic plasticity and neurological disorders, respectively. We summarize the influence of MMP-9 on the dynamic remodeling of the ECM via the cleavage of extracellular substrates. We discuss its role in the formation, modification, and maintenance of dendritic spines in learning and memory. Finally, we review research that implicates MMP-9 in aberrant synaptic plasticity and spine dysmorphology in neurological disorders, with a focus on morphological abnormalities of dendritic protrusions that are associated with epilepsy.

The Peptide Network between Tetanus Toxin and Human Proteins Associated with Epilepsy

Sequence matching analyses show that Clostridium tetani neurotoxin shares numerous pentapeptides (68, including multiple occurrences) with 42 human proteins that, when altered, have been associated with epilepsy. Such a peptide sharing is higher than expected, nonstochastic, and involves tetanus toxin-derived epitopes that have been validated as immunopositive in the human host. Of note, an unexpected high level of peptide matching is found in mitogen-activated protein kinase 10 (MK10), a protein selectively expressed in hippocampal areas. On the whole, the data indicate a potential for cross-reactivity between the neurotoxin and specific epilepsy-associated proteins and may help evaluate the potential risk for epilepsy following immune responses induced by tetanus infection. Moreover, this study may contribute to clarifying the etiopathogenesis of the different types of epilepsy.

Developmental dyscalculia in children and adolescents with idiopathic epilepsies in a Brazilian sample

Epilepsy is one of the most prevalent chronic disorders of childhood which can threaten child development and mental health. Among cognitive disorders, dyscalculia is one of the most important. In this study, 39 children and adolescents with idiopathic epilepsy underwent clinical and neuropsychological assessment to determine the intellectual level, math skills, reading and writing performance and neuropsychological profile. It was observed that the mathematical ability was below schooling expectations in a higher frequency than expected. There were no significant differences in mathematical performance among groups divided by number of antiepileptic drugs used, duration of disease and types and frequency of seizures. There was a positive correlation with intelligence quotient and attentional and reading level. These results suggest the existence not only of dyscalculia, but the concurrence of attentional and reading problems for the poor mathematical performance in this population.

Combining Parent–Child Interaction Therapy and Visual Supports for the Treatment of Challenging Behavior in a Child With Autism and Intellectual Disabilities and Comorbid Epilepsy

About one in six children has one or more developmental disabilities, which include autism spectrum disorder (ASD) and intellectual disabilities (ID). Individuals with both ASD and ID are at higher risk of epilepsy, and those with younger onset of seizures are at higher risk of both developmental and behavioral disorders. Young children presenting with developmental and behavioral challenges are often very difficult for caregivers to manage, and challenging behavior results in reduced learning opportunities. Finding effective and efficient interventions to address behavioral issues remains a clinical priority to improve overall outcomes for all children and especially those with developmental disabilities. This case study presents the treatment of a 5-year-old girl diagnosed with ASD, ID, and comorbid epilepsy using Parent–Child Interaction Therapy (PCIT) combined with visual supports (VS). Findings from this case report documented (a) an improvement in behavioral functioning in home, school, and community settings; (b) evidence for the effectiveness of parent-mediated intervention; and (c) support for collaboration and care coordination to improve intervention outcomes.

The challenges and innovations for therapy in children with epilepsy

Major advances have been made in the diagnosis, evaluation and management of children with epilepsy over the past 15 years. There has been a marked increase in genetic diagnoses of a number of key childhood-onset epilepsy syndromes, such as Dravet syndrome, which has been linked to mutations in the SCN1A gene. The reorganization and reclassification of epilepsies, devised by the International League Against Epilepsy, has stimulated specialists to reassess their diagnostic practices; however, many studies have not addressed the global issues in treating children with epilepsy-specifically, the challenges of diagnosis through to optimal, and appropriate, therapeutic management. Also, Class I evidence-based data that are needed as a foundation for the development of treatment guidelines worldwide are lacking. Epilepsy is common, and the impact of this disease crosses age ranges and should be managed at all levels of care from community to quaternary care. In this Review, existing data and new therapeutic management approaches are discussed with the aim of highlighting the incidence of standard practices that may not be based on clinical evidence.

Self-Esteem, Social Phobia and Depression Status in Patients with Epilepsy

INTRODUCTION

The increased risk for psychiatric disorders in epilepsy can be related to a number of clinical, psychosocial and biological factors. Due to the unpredictability of seizures and the possibility that they may occur at any time and in any place, patients with epilepsy may develop social phobia and may have feelings of worthlessness and stigma. These factors decrease their psychosocial function, self-efficacy, and quality of life and even increase the suicide rate. Considering the above-mentioned scientific data, the present study was designed to investigate phobia, self-esteem and depression status in patients with epilepsy.

METHODS

One hundred thirty-two patients (aged 21-52 years) and age- and gender-matched control group of 61 subjects (aged 25-60 years) were included in this study. All patients in both groups were administered the Liebowitz Social Anxiety Scale (LSAS), Coopersmith Self-Esteem Inventory (CSEI), and the Beck Depression Inventory (BDI).

RESULTS

The mean ages of the patient group and the healthy controls were 29.66±11.3 and 32.16±7.99, respectively. There was no statistical significance between the two groups in terms of age and sex (p>0.05). BDI, LSAS and CSEI scores in the patient group were statistically significantly different than in the control group (p<0.05).

DISCUSSION

Our results showed that social phobia, lower self-esteem and depression are important comorbid conditions in epileptic patients. Psychiatric disorders are usually underrecognized and undertreated in patients with epilepsy. Therefore, it is very important to identify and treat the psychiatric comorbid conditions in epilepsy because of their significant burden on patients' quality of life.

Determinants of intelligence in childhood-onset epilepsy: a single-center study

The purpose of this study was to quantify the intelligence of children with epilepsy and to determine the clinical factors associated with intellectual impairment. The medical records of patients diagnosed with childhood-onset epilepsy at a single tertiary medical center in Korea between 2006 and 2011 were retrospectively reviewed. The Korean Education Development Institute-Wechsler Intelligence Scale for Children or Korean Wechsler Intelligence Scale for adults was used to quantify the level of intelligence. Age at seizure onset, etiology, epilepsy duration, number of seizures in the last year, use of antiepileptic drugs, EEG/MRI findings, and epilepsy classification were recorded. The association between clinical factors and the intelligence was determined using logistic regression. Three hundred and twenty-two patients were included in the analysis. One hundred and seventy-six (54.7%) patients had low intelligence (intelligence quotient [IQ]<80) with 18 (5.6%) defined as borderline mental retardation (IQ 70-79), 47 (14.6%) as mild mental retardation (IQ 60-69), and 111 (34.5%) as moderate-to-severe mental retardation (IQ<60). Epilepsy duration, number of seizures in the last year, and epilepsy classification were significantly associated with low intelligence in multivariate logistic regression (p<0.05). However, when analyzed according to etiology, these factors were not associated with low intelligence in children with idiopathic epilepsy. The most important factors associated with low intelligence in childhood-onset epilepsy are the underlying etiology and, in cryptogenic and symptomatic epilepsy, seizure burden. The results of this study underscore the importance of seizure control to alleviate the harmful impact of epilepsy on cognition.

Priorities in pediatric epilepsy research: improving children's futures today

The Priorities in Pediatric Epilepsy Research workshop was held in the spirit of patient-centered and patient-driven mandates for developing best practices in care, particularly for epilepsy beginning under age 3 years. The workshop brought together parents, representatives of voluntary advocacy organizations, physicians, allied health professionals, researchers, and administrators to identify priority areas for pediatric epilepsy care and research including implementation and testing of interventions designed to improve care processes and outcomes. Priorities highlighted were 1) patient outcomes, especially seizure control but also behavioral, academic, and social functioning; 2) early and accurate diagnosis and optimal treatment; 3) role and involvement of parents (communication and shared decision-making); and 4) integration of school and community organizations with epilepsy care delivery. Key factors influencing pediatric epilepsy care included the child's impairments and seizure presentation, parents, providers, the health care system, and community systems. Care was represented as a sequential process from initial onset of seizures to referral for comprehensive evaluation when needed. We considered an alternative model in which comprehensive care would be utilized from onset, proactively, rather than reactively after pharmacoresistance became obvious. Barriers, including limited levels of evidence about many aspects of diagnosis and management, access to care--particularly epilepsy specialty and behavioral health care--and implementation, were identified. Progress hinges on coordinated research efforts that systematically address gaps in knowledge and overcoming barriers to access and implementation. The stakes are considerable, and the potential benefits for reduced burden of refractory epilepsy and lifelong disabilities may be enormous.

Are vesicular neurotransmitter transporters potential treatment targets for temporal lobe epilepsy?

The vesicular neurotransmitter transporters (VNTs) are small proteins responsible for packing synaptic vesicles with neurotransmitters thereby determining the amount of neurotransmitter released per vesicle through fusion in both neurons and glial cells. Each transporter subtype was classically seen as a specific neuronal marker of the respective nerve cells containing that particular neurotransmitter or structurally related neurotransmitters. More recently, however, it has become apparent that common neurotransmitters can also act as co-transmitters, adding complexity to neurotransmitter release and suggesting intriguing roles for VNTs therein. We will first describe the current knowledge on vesicular glutamate transporters (VGLUT1/2/3), the vesicular excitatory amino acid transporter (VEAT), the vesicular nucleotide transporter (VNUT), vesicular monoamine transporters (VMAT1/2), the vesicular acetylcholine transporter (VAChT) and the vesicular γ-aminobutyric acid (GABA) transporter (VGAT) in the brain. We will focus on evidence regarding transgenic mice with disruptions in VNTs in different models of seizures and epilepsy. We will also describe the known alterations and reorganizations in the expression levels of these VNTs in rodent models for temporal lobe epilepsy (TLE) and in human tissue resected for epilepsy surgery. Finally, we will discuss perspectives on opportunities and challenges for VNTs as targets for possible future epilepsy therapies.

Adaptive behavior and later school achievement in children with early-onset epilepsy

AIM

To determine whether early measures of adaptive behavior are predictive of later school difficulties and achievement in otherwise neurotypical (unimpaired) children with onset of epilepsy during the preschool years.

METHOD

In a prospective cohort study, parents completed the Vineland Adaptive Behavior Scales (VABS) for children who were aged 5 years or less at epilepsy diagnosis. Eight to 9 years later, the children were assessed using the Wechsler Intelligence Scales for Children (WISC), the Wide Range Achievement Test (WRAT), and the Child Behavior Checklist (CBCL). Associations of VABS scores with later WRAT and CBCL scores were tested.

RESULTS

A total of 108 neurotypical children (64 males, 44 females; mean age at testing 11 y 11 mo, SD 2 y) were studied. After adjustment for IQ and other factors, there was an increase of 0.15 points (95% confidence interval [CI] 0.03-0.27 points; p=0.03) and 0.14 points (95% CI 0.0-0.28 points; p=0.05) in WRAT reading and spelling scores for each 1-point increment in the VABS communication score. Corresponding numbers for the VABS socialization score were 0.20 (95% CI 0.08-0.32; p=0.005) and 0.17 (95% CI 0.05-0.29; p=0.005).

CONCLUSION

In neurotypical preschool children with epilepsy, early social and communication scores predict later school performance. These findings raise questions about opportunities for early identification and intervention for children at greatest risk.

Characterization of a dopamine transporter polymorphism and behavior in Belgian Malinois

BACKGROUND

The Belgian Malinois dog breed (MAL) is frequently used in law enforcement and military environments. Owners have reported seizures and unpredictable behavioral changes including dogs' eyes "glazing over," dogs' lack of response to environmental stimuli, and loss of behavioral inhibition including owner-directed biting behavior. Dogs with severe behavioral changes may be euthanized as they can represent a danger to humans and other dogs. In the dog, the dopamine transporter gene (DAT) contains a 38-base pair variable number tandem repeat (DAT-VNTR); alleles have either one or two copies of the 38-base pair sequence. The objective of this study was to assess frequency of DAT-VNTR alleles, and characterize the association between DAT-VNTR alleles and behavior in MAL and other breeds.

RESULTS

In an American sample of 280 dogs comprising 26 breeds, most breeds are predominantly homozygous for the DAT-VNTR two-tandem-repeat allele (2/2). The one-tandem-repeat allele is over-represented in American MAL (AM-MAL) (n = 144), both as heterozygotes (1/2) and homozygotes (1/1). All AM-MAL with reported seizures (n = 5) were 1/1 genotype. For AM-MAL with at least one "1" allele (1/1 or 1/2 genotype, n = 121), owners reported higher levels of attention, increased frequency of episodic aggression, and increased frequency of loss of responsiveness to environmental stimuli. In behavior observations, Belgian Military Working Dogs (MWD) with 1/1 or 1/2 genotypes displayed fewer distracted behaviors and more stress-related behaviors such as lower posture and increased yawning. Handlers' treatment of MWD varied with DAT-VNTR genotype as did dogs' responses to handlers' behavior. For 1/1 or 1/2 genotype MWD, 1) lower posture after the first aversive stimulus given by handlers was associated with poorer obedience performance; 2) increased aversive stimuli during protection exercises were associated with decreased performance; 3) more aversive stimuli during obedience were associated with more aversive stimuli during protection; and 4) handlers used more aversive stimuli in protection compared with obedience exercises.

CONCLUSIONS

The single copy allele of DAT-VNTR is associated with owner-reported seizures, loss of responsiveness to environmental stimuli, episodic aggression, and hyper-vigilance in MAL. Behavioral changes are associated with differential treatment by handlers. Findings should be considered preliminary until replicated in a larger sample.

Mammalian target of rapamycin complex 1 activation negatively regulates Polo-like kinase 2-mediated homeostatic compensation following neonatal seizures

Homeostatic plasticity is characterized by compensatory changes in synaptic strength and intrinsic membrane properties in response to chronic changes in neuronal activity. Neonatal seizures are a naturally occurring source of neuronal overactivation and can lead to long-term epilepsy and cognitive deficits. Using a rodent model of hypoxia-induced neonatal seizures that results in a persistent increase in AMPA receptor (AMPAR) function in hippocampal CA1 pyramidal neurons, we aimed to determine whether there was any evidence of an opposing endogenous homeostatic antiepileptic response. Given that this model results in long-term epilepsy, we also examined mechanisms whereby this homeostasis fails. Whole-cell patch-clamp recordings from neurons in slices removed at intervals following seizure onset revealed an initial up-regulation of AMPAR function that was followed by a transient dynamic attenuation of this enhancement by 48-72 h, although AMPAR function was still increased compared with nonseizure control baseline. This secondary down-regulation of enhanced AMPAR function was coincident with a marked transient increase in expression and function of the Polo-like kinase 2 (PLK2), which has previously been implicated in homeostatic down-regulation of neuronal excitability in cell/slice culture models. The effects were transient and at 1 wk AMPAR function once again became up-regulated, simultaneous with a decrease in PLK2 expression and function. This negative regulation was mediated by subacute postseizure increases in mammalian target of rapamycin (mTOR). Application of the mTOR inhibitor rapamycin prevented post-hypoxic seizure impairment of homeostasis, suggesting that homeostatic plasticity mechanisms may be potentially modifiable therapeutic targets in epileptogenesis.

Altered Rolandic gamma-band activation associated with motor impairment and ictal network desynchronization in childhood epilepsy

Epilepsy is associated with an abnormal expression of neural oscillations and their synchronization across brain regions. Oscillatory brain activation and synchronization also play an important role in cognition, perception and motor control. Childhood epilepsy is associated with a variety of cognitive and motor deficits, but the relationship between altered functional brain responses in various frequency ranges and functional impairment in these children remains poorly understood. We investigated functional magnetoencephalographic (MEG) responses from motor cortex in multiple functionally relevant frequency bands following median nerve stimulation in twelve children with epilepsy, including four children with motor impairments. We demonstrated that children with motor impairments exhibit an excessive gamma-band response from Rolandic cortex, and that the magnitude of this Rolandic gamma response is negatively associated with motor function. Abnormal responses from motor cortex were also associated with ictal desynchronization of oscillations within Rolandic cortex measured using intracranial EEG (iEEG). These results provide the evidence that ictal disruption of motor networks is associated with an altered functional response from motor cortex, which is in turn associated with motor impairment.