The relationship between sleep and epilepsy: the effect on cognitive functioning in children

Nonconvulsive status epilepticus complicating epstein-barr virus encephalitis in a child

Children with acute encephalopathy show prolonged electrographic seizure activity consistent with nonconvulsive status epilepticus (NCSE). Pediatric NCSE is a heterogeneous clinical entity with poor outcome and different etiologies, including central nervous system infection, stroke, toxic-metabolic syndrome, and epileptic syndrome. We report a 4-year-old girl with seizure and behavioral changes in whom the analysis of cerebrospinal fluid by polymerase chain reaction was positive for Epstein-Barr virus. We emphasize the importance of electroencephalography (EEG), and particularly, of continuous EEG monitoring for early recognition and appropriate treatment of this condition.

Memory consolidation in children with epilepsy: does sleep matter?

INTRODUCTION

Children with epilepsy have frequent sleep disturbance and challenges in learning and memory. There is little research on the consolidation of memory during sleep in this population. The goal of this pilot study was to determine whether children with epilepsy are able to consolidate memories better after a sleep versus wake period as has been demonstrated in typically developing children.

METHODS

This study was a prospective evaluation of children with epilepsy to determine if sleep improved episodic memory (using word lists) as compared with memory following a wake period of similar duration. The study was conducted in patients in the Epilepsy Monitoring Unit at a single academic health science center. In the sleep recall condition, the learning trials were presented in the evening, and delayed recall of the words was tested in the morning. In the wake condition, the learning took place in the morning, and the delayed recall took place later in the day. Subjects wore an actigraph to evaluate sleep/wake patterns. Data regarding the children's epilepsy, antiepileptic medications, and frequency of interictal epileptiform discharges were also documented.

RESULTS

Ten children (agd 8-17years) participated in the study. For the entire sample, recall after sleep was better than recall after awake (p=0.03), and 7 of the 10 children showed this effect. However, reanalyses removing an outlier showed no difference between the two recall conditions. The mean number of interictal epileptiform discharges was 8.8 during the recall after sleep and 7.8 during the recall after awake. Three children had seizures during the evaluation.

CONCLUSION

In this pilot study, we demonstrated that a small cohort of children with epilepsy, with similar interictal epileptiform discharges during sleep and wake, showed no advantage in memory for a word list after a period of sleep than after a period of being awake. This finding requires further study in a larger cohort. Poor memory consolidation during sleep may contribute to the cognitive deficits in children with epilepsy.

The cooccurrence of interictal discharges and seizures in pediatric sleep-disordered breathing

Studies in the literature data have shown that the prevalence of obstructive sleep apnea (OSA) in children with epilepsy is high and that treatment for OSA leads to a reduction in the number of seizures; by contrast, few studies have demonstrated an increased prevalence of interictal epileptiform discharges (IEDs) or epilepsy in children with sleep-disordered breathing (SDB). The aim of the present study was to confirm the high prevalence of IEDs or epilepsy in a large sample of children with SDB and to collect follow-up data. Children were recruited prospectively and underwent their first video-polysomnography (video-PSG) for SDB in a teaching hospital sleep center. Of the 298 children who fulfilled the diagnostic criteria for sleep-disordered breathing, 48 (16.1%) children were found to have IEDs, three of these 48 children were also found to have nocturnal seizures (two females diagnosed with rolandic epilepsy and a male diagnosed with frontal lobe epilepsy). Only 11 subjects underwent a second video-PSG after 6months; at the second video-PSG, the IEDs had disappeared in six subjects, who also displayed a reduced AHI and an increased mean overnight saturation. Thirty-eight of the 250 children without IEDs underwent a second video-PSG after 6months. Of these 250 children, four, who did not display any improvement in the respiratory parameters and were found to experience numerous stereotyped movements during sleep, were diagnosed with nocturnal frontal lobe epilepsy. Our study confirms the high prevalence of IEDs in children with SDB. Follow-up data indicate that they may recede over time, accompanied by an improvement of sleep respiratory parameters.

Case reports of sleep phenotypes of ADHD: from hypothesis to clinical practice

OBJECTIVE

Five sleep ADHD phenotypes have been hypothesized: (a) the hypo-arousal state of the "primary" form of ADHD, (b) the sleep phase advanced disorder, (c) sleep disordered breathing (SDB), (d) restless legs syndrome and/or periodic limb movements disorder (PLMD), and (e) epilepsy.

METHOD

Five case reports are presented; each child but one underwent video-polysomnography.

RESULTS

The first case report is an example of ADHD and SDB, with improvement of hypersomnolence after resolution of sleep apnea. The second case shows the impact of delayed sleep onset latency in the pathogenesis of ADHD, and the efficacy of melatonin. The third case report describes the association with PLMD, with amelioration after iron supplementation. The other two cases are examples of ADHD and epilepsy, with clinical improvement after antiepileptic treatment was started.

CONCLUSION

A diagnostic and therapeutic algorithm should be designed to find the best first-line treatment for ADHD and sleep problems/epilepsy.

Epileptic encephalopathies in adults and childhood

Epileptic encephalopathies are motor-mental retardations or cognitive disorders secondary to epileptic seizures or epileptiform activities. Encephalopaties due to brain damage, medications, or systemic diseases are generally not in the scope of this definition, but they may rarely accompany the condition. Appropriate differential diagnosis of epileptic seizures as well as subclinical electroencephalographic discharges are crucial for management of seizures and epileptiform discharges and relative regression of cognitive deterioration in long-term followup. Proper antiepileptic drug, hormonal treatment, or i.v. immunoglobulin choice play major role in prognosis. In this paper, we evaluated the current treatment approaches by reviewing clinical electrophysiological characteristics of epileptic encephalopathies.

The sleep phenotypes of attention deficit hyperactivity disorder: the role of arousal during sleep and implications for treatment

About 25-50% of children and adolescents with attention-deficit hyperactivity disorder (ADHD) experience sleep problems. An appropriate assessment and treatment of such problems might improve the quality of life in such patients and reduce both the severity of ADHD and the impairment it causes. According to data in the literature and to the overall complexity of the interaction between ADHD and sleep, five sleep phenotypes may be identified in ADHD: (i) a sleep phenotype characterized mainly by a hypo-arousal state, resembling narcolepsy, which may be considered a "primary" form of ADHD (i.e. without the interference of other sleep disorders); (ii) a phenotype associated with delayed sleep onset latency and with a higher risk of bipolar disorder; (iii) a phenotype associated with sleep disordered breathing (SDB); (iv) another phenotype related to restless legs syndrome (RLS) and/or periodic limb movements; (v) lastly, a phenotype related to epilepsy/or EEG interictal discharges. Each sleep phenotype is characterized by peculiar sleep alterations expressed by either an increased or decreased level of arousal during sleep that have important treatment implications. Treatment with stimulants is recommended above all in the primary form of ADHD, whereas treatment of the main sleep disorders or of co-morbidities (i.e. bipolar disorders and epilepsy) is preferred in the other sleep phenotypes. All the sleep phenotypes, except the primary form of ADHD and those related to focal benign epilepsy or focal EEG discharges, are associated with an increased level of arousal during sleep. Recent studies have demonstrated that both an increase and a decrease in arousal are ascribable to executive dysfunctions controlled by prefrontal cortical regions (the main cortical areas implicated in the pathogenesis of ADHD), and that the arousal system, which may be hyperactivated or hypoactivated depending on the form of ADHD/sleep phenotype.

"Electro-clinical syndromes" with onset in paediatric age: the highlights of the clinical-EEG, genetic and therapeutic advances

The genetic causes underlying epilepsy remain largely unknown, and the impact of available genetic data on the nosology of epilepsy is still limited. Thus, at present, classification of epileptic disorders should be mainly based on electroclinical features. Electro-clinical syndrome is a term used to identify a group of clinical entities showing a cluster of electro-clinical characteristics, with signs and symptoms that together define a distinctive, recognizable, clinical disorder. These often become the focus of treatment trials as well as of genetic, neuropsychological, and neuroimaging investigations. They are distinctive disorders identifiable on the basis of a typical age onset, specific EEG characteristics, seizure types, and often other features which, when taken together, permit a specific diagnosis which, in turn, often has implications for treatment, management, and prognosis. Each electro-clinical syndrome can be classified according to age at onset, cognitive and developmental antecedents and consequences, motor and sensory examinations, EEG features, provoking or triggering factors, and patterns of seizure occurrence with respect to sleep. Therefore, according to the age at onset, here we review the more frequently observed paediatric electro-clinical syndrome from their clinical-EEG, genetic and therapeutic point of views.

Is sleep-related consolidation impaired in focal idiopathic epilepsies of childhood? A pilot study

We investigated sleep-related declarative memory consolidation in four children with focal idiopathic epilepsy. In a population of healthy control children, recall of learned pairs of words was increased after a night of sleep, but not after a daytime wakefulness period. In children with epilepsy (1 case of benign epilepsy with centro-temporal spikes, 1 case of benign childhood epilepsy with occipital paroxysms, and 2 cases of epileptic encephalopathy (EE) with continuous spike and waves during slow-wave sleep, CSWS), recall performance significantly decreased overnight, suggesting impairment in sleep-related declarative memory consolidation. Hydrocortisone treatment in one patient with EE with CSWS resulted in normalization of the sleep EEG together with normalization of overnight memory performance, which was not the case in the other EE/CSWS patient whose sleep EEG was only partially improved. These preliminary results suggest that interictal epileptiform discharges in idiopathic focal epilepsies may disrupt the brain processes underlying sleep-related memory consolidation.

A brief primer on sleep for pediatric and child clinical neuropsychologists

Sleep problems are common in the children seen by pediatric and child clinical neuropsychologists, and these problems have the potential to significantly impact the child and his or her family. All are treatable to some degree, and some respond extremely well to existing treatments. This article provides a brief overview of the impact, nature, screening, and treatment for childhood sleep problems, with a particular emphasis on issues relevant to practicing neuropsychologists.

Psychosocial issues for children with epilepsy

Epilepsy is a pervasive disorder that consists not only of seizures, but of behavioral, academic, and social difficulties. Epilepsy has an impact on the entire family and may have a significant effect on the interrelationships between child and parent. Epilepsy also has a potentially deleterious effect on academic functioning that may be the result of central nervous system dysfunction, seizures, antiepileptic drugs, or child and family response to illness. Early assessment for psychosocial problems and appropriate interventions can be beneficial for the child and family. Particular attention should be paid to periods of transition such as the move from adolescence to adulthood.

The effects of the ketogenic diet on behavior and cognition

Multiple forms of the ketogenic diet (KD) have been successfully used to treat drug-resistant epilepsy, however its mainstream use as a first-line therapy is still limited. Further investigation into its clinical efficacy as well as the molecular basis of activity is likely to assist in the reversal of any resistance to its implementation. In this review we shall attempt to elucidate the current state of experimental and clinical data concerning the neuroprotective and cognitive effects of the KD in both humans and animals. Generally, it has been shown by many research groups that effective implementation of KD exerts strong neuroprotective effects with respect to social behavior and cognition. We will also elucidate the role of KD in the interesting relationship between sleep, epilepsy and memory. Currently available evidence also indicates that, under appropriate control, and with further studies investigating any potential long-term side effects, the KD is also a relatively safe intervention, especially when compared to traditional anti-epileptic pharmacotherapeutics. In addition, due to its neuroprotective capacity, the KD may also hold potential benefit for the treatment of other neurological or neurodegenerative disorders.

Sleep problems in children and adolescents with common medical conditions

Untreated sleep disturbances and sleep disorders pose significant adverse daytime consequences and place children at considerable risk for poor health outcomes. Sleep disturbances occur at a greater frequency in children with acute and chronic medical conditions compared with otherwise healthy peers. Sleep disturbances in medically ill children can be associated with sleep disorders, comorbid with acute and chronic conditions, or secondary to underlying disease-related mechanisms, treatment regimens, or hospitalization. Clinical management should include a multidisciplinary approach with particular emphasis on routine, regular sleep assessments and prevention of daytime consequences, and promotion of healthy sleep habits and health outcomes.

A role for sleep disruption in cognitive impairment in children with epilepsy

Early-onset epilepsy is associated with a poor cognitive outcome, with the cumulative burden of both ictal and interictal epileptiform discharges likely to contribute significantly. Memory consolidation has been shown to occur during sleep in healthy children, with an associated electroencephalographic signature. This may be disrupted in children with epilepsy, who exhibit a high incidence of sleep disorders, whether directly related to their seizures or as a comorbidity. Conversely, seizure semiology may be influenced by sleep. In this review we present clinical and experimental evidence that suggests that the disruption of sleep architecture by epileptiform discharges may be an important factor contributing to cognitive impairment in children with epilepsy.

"Epileptic encephalopathy" of infancy and childhood: electro-clinical pictures and recent understandings

There is growing interest in the diagnosis of cognitive impairment among children with epilepsy. It is well known that status of seizures control has to be carefully investigated because it can be sufficient "per se" to cause progressive mental deterioration conditions. Subclinical electroencephalographic discharges may have subtle effects on cognition, learning and sleep patterns, even in the absence of clinical or sub-clinical seizures. In this respect, electroencephalographic monitoring (long-term and nocturnal recording) and in particular an all night video-polysomnography (V-NPSG) record can be crucial to detect the presence of unrecognized seizures and/or an inter-ictal nocturnal EEG discharge increasing. Epileptic encephalopathies (EE) are a group of conditions in which the higher cognitive functions are deteriorate as a consequence of epileptic activity, which, in fact, consists of frequent seizures and/or florid and prolonged interictal paroxysmal discharges, focal or generalized. AEDs represent the first line in opposing the burden of both, the poor seizures control and the poor interictal discharges control, in the cognitive deterioration of EE affected children. Thus, to improve the long-term cognitive/behavioural prognosis in these refractory epileptic children, it should be taken into account both a good seizures control and a strict sleep control, choosing carefully antiepileptic drugs which are able to control not only seizures clinically recognizable but even the EEG discharges onset and its increasing and spreading during sleep. Here, we review the efficacy and safety of the newer AEDs that, to date, are used in the treatment of EE in infancy and childhood.