Infantile spams without hypsarrhythmia: a study of 16 cases

Three Patients of the Early Onset Epileptic Spasms without Hypsarrhythmia

Epileptic spasms without hypsarrhythmia occur when patients do not display hypsarrhythmia on electroencephalogram (EEG) at the onset and throughout the clinical course. We report three patients of epileptic spasms in patients with early onset, all of whom experienced other types of seizures.We detail three patients (two boys and one girl) of epileptic spasms without hypsarrhythmia, occurring between 1 and 3 months of age, with no abnormalities detected on neurometabolic analysis and brain magnetic resonance imaging. Long-term video-EEG monitoring revealed epileptic spasms with focal onset seizures in two patients, and epileptic spasms followed by generalized tonic-clonic seizures in one patient. Hypsarrhythmia was never observed in repeated EEG examinations. Two patients achieved seizure freedom and improved development through treatment with topiramate alone or in combination with valproate, without requiring hormonal therapies or vigabatrin. The remaining patient achieved seizure freedom following administration of antiseizure medications, including topiramate, after a trial of adrenocorticotropic hormone therapy.We report the cases of three patients with early onset epileptic spasms without hypsarrhythmia. All patients achieved seizure freedom after topiramate treatment. Topiramate may be considered as a relatively effective antiseizure medication for early onset epileptic spasms without hypsarrhythmia.

Electroclinical Features of Infantile Epileptic Spasms Syndrome

Epileptic spasms are a unique, age-dependent manifestation of epilepsies in infancy and early childhood, commonly occurring as part of infantile epileptic spasms syndrome. Developmental stagnation and subsequent decline may occur in children with epileptic spasms, partly due to the abundant high-amplitude interictal epileptiform and slow wave abnormalities. Early recognition and treatment of epileptic spasms, along with the reversal of the electroencephalography (EEG) findings, are critical for improving outcomes. Recognizing hypsarrhythmia and its variations is key to confirming the diagnosis. The various patterns of hypsarrhythmia are not etiology specific, but could indicate the severity of the disease. Several scoring systems have been proposed to improve the inter-rater reliability of recognizing hypsarrhythmia and to assess EEG progress in response to treatment. Ictal patterns during spasms are brief and composed of slow waves, sharp transients, fast activity, and voltage attenuation, either in isolation or more commonly as a combination of these waveforms. Ictal patterns are commonly diffuse, but may be lateralized to one hemisphere in children with structural etiology. A subset of patients with epileptic spasms has a surgically remediable etiology, with readily identifiable lesions on neuroimaging in most cases. Asymmetry in epileptic spasms, concurrent focal seizures, and asymmetric interictal and ictal EEG findings may be present, but a lack of focality in electrophysiological findings is not uncommon. Intracranial EEG features of epileptic spasms have been described, but the utility of intracranial EEG monitoring in surgical candidates with overt focal epileptogenic lesions on magnetic resonance imaging is questionable, and surgery could be performed using noninvasive data.

Epileptic spasms in clusters without hypsarrhythmia in infancy and childhood: A single age-dependent type of epilepsy or well-defined epileptic syndrome?

OBJECTIVE

In this study, we present the electroclinical features and outcomes of 92 patients with epileptic spasms (ES) in clusters without modified or classical hypsarrhythmia that started in either in infancy or in childhood; we compared both groups in terms of electroclinical features, etiology, treatment, evolution, and outcome.

METHODS

Between June 2000 and July 2022, 92 patients met the electroclinical diagnostic criteria of ES in clusters without hypsarrhythmia. Patients with ES associated with other epileptic encephalopathies including West Syndrome, as well as those with the specific etiology of ES and developmental and epileptic encephalopathy associated with CDKL5 were excluded.

RESULTS

The patients were divided into two groups based on the age at ES onset: those with ES onset before (Group 1) and those with ES onset after 2 years of age (Group 2). The features of ES and the type of associated seizures before and after ES onset, as well as the interictal and ictal EEG and electromyography findings were similar in both groups. The etiologies were mainly structural (40.2%), genetic (11.9%), and unknown (44.6%) in majority of the patients in both groups. Thirty-one patients were seizure-free, while in the remaining patients the seizures continued. Nine patients (9.8%) with unilateral structural lesions underwent surgery with good results. The neurological abnormalities and developmental findings prior to ES onset depended on the underlying etiology.

CONCLUSION

Our series of patients may represent a well-defined epileptic syndrome or type of epilepsy with onset in infancy or childhood characterized by ES in clusters without hypsarrhythmia associated with focal and generalized seizures and EEG paroxysms without neurological deterioration.

The vigabatrin-associated brain abnormalities on MRI and their differential diagnosis

Vigabatrin is an anti-epileptic drug that inhibits the enzyme γ-aminobutyric acid (GABA)-transaminase. The anticonvulsant effect of vigabatrin involves increasing GABA levels and attenuating glutamate-glutamine cycling. Vigabatrin indications include infantile spasms and refractory focal seizures. Despite having a significant role in paediatric epileptology, vigabatrin has adverse effects, such as retinal toxicity, in up to 30% of patients after 1 year of use and brain abnormalities on magnetic resonance imaging (MRI). The percentage of patients with brain abnormalities on MRI varies between 22-32% of children using vigabatrin to treat infantile spasms. Risk factors for presenting these imaging abnormalities are cryptogenic infantile spasms, age <12 months old, high dosage, and possible concomitant hormonal therapy. Clinically, these abnormalities are usually asymptomatic. Histopathological analysis reveals white matter vacuolation and intramyelinic oedema. The typical findings of vigabatrin-associated brain abnormalities on MRI are bilateral and have a symmetrical hyperintense signal on T2-weighted imaging, with diffusion restriction, that often compromise the globi pallidi, thalami, subthalamic nuclei, cerebral peduncles, midbrain, dorsal brainstem, including the medial longitudinal fasciculi, and dentate nuclei of the cerebellum. In this article, the authors intend to review the clinical manifestations, histopathological features, imaging aspects, and differential diagnosis of vigabatrin-associated brain abnormalities on MRI.

Infantile Spasms without Hypsarrhythmia and Paroxysmal Eye-Head Movements in an Infant with a Pyridoxine-Dependent Epilepsy due to PLPBP/PLPHP Deficiency

To describe a new phenotype and the diagnostic workup of a vitamin-B6-dependent epilepsy due to pyridoxal 5'-phosphate-binding protein (PLPBP) deficiency in an infant with early-onset epilepsy at the age of 5 years 6 months. Following immediate and impressive clinical response to treatment with pyridoxine, metabolic screening for vitamin-B6-dependent epilepsies and targeted next-generation sequencing (NGS)-based gene panel analysis were performed. Potentially pathogenic variants were confirmed by Sanger sequencing in the patient, and variants were analyzed in both parents to confirm biallelic inheritance. The clinical phenotype and course of disease were compared to the 44 cases reported in the literature, harboring variants in pyridoxal phosphate homeostasis protein (PLPHP) and with cases of vitamin-B6-dependent epilepsy due to other known causative genes. Levels of alpha-aminoadipic semialdehyde in urine and amino acids were normal. Two inherited pathogenic variations in PLPHP were found in compound heterozygosity, including one novel deletion. We here describe a previously unreported individual harboring biallelic pathogenic PLPHP variants presenting with paroxysmal eye-head movements followed by epileptic spasms and an almost normal interictal electroencephalogram, thus expanding the clinical spectrum of PLPBP deficiency. This warrants consideration of vitamin-B6-dependent epilepsies in patients with early-onset epilepsy, including epileptic spasms, and eye movement disorders also beyond the neonatal period even when metabolic screening for vitamin-B6-dependent epilepsies is negative. PLPHP should be included systematically in NGS epilepsy gene panels.

Longitudinal evolution of electroencephalogram (EEG): Findings over five years of follow-up in children with Zika-related microcephaly from the Microcephaly Epidemic Research Group Pediatric Cohort (2015-2020)

OBJECTIVE

To assess the longitudinal evolution of EEG findings in children with Zika related-microcephaly (ZRM) and to evaluate the associations of these patterns with the children's clinical and neuroimaging characteristics.

METHODS

As part of the follow-up of the Microcephaly Epidemic Research Group Pediatric Cohort (MERG-PC) in Recife, Brazil, we performed serial EEG recordings in a subgroup of children with ZRM to evaluate changes in background rhythms and epileptiform activity (EA). Latent class analysis was used to identify patterns in the evolution of EA over time; clinical and neuroimaging findings were compared across the identified groups.

RESULTS

Out of the 72 children with ZRM who were evaluated during 190 EEGs/videoEEGs, all participants presented with abnormal background activity, 37.5% presented with an alpha-theta rhythmic activity, and 25% presented with sleep spindles, which were less commonly observed in children with epilepsy. EA changed over time in 79.2% of children, and three distinct trajectories were identified: (i) multifocal EA over time, (ii) no discharges/focal EA evolving to focal/multifocal EA, and (iii) focal/multifocal EA evolving to epileptic encephalopathy patterns (e.g., hypsarrhythmia or continuous EA in sleep). The multifocal EA over time trajectory was associated with periventricular and thalamus/basal ganglia calcifications, brainstem and corpus callosum atrophy and had less focal epilepsy, whereas the children in the trajectory which evolved to epileptic encephalopathy patterns had more frequently focal epilepsy.

SIGNIFICANCE

These findings suggest that, in most children with ZRM, trajectories of changes in EA can be identified and associated with neuroimaging and clinical features.

Neurobehavioral deficits and a progressive ictogenesis in the tetrodotoxin model of epileptic spasms

OBJECTIVE

Our goal was to determine whether animals with a history of epileptic spasms have learning and memory deficits. We also used continuous (24/7) long-term electroencephalographic (EEG) recordings to evaluate the evolution of epileptiform activity in the same animals over time.

METHODS

Object recognition memory and object location memory tests were undertaken, as well as a matching to place water maze test that evaluated working memory. A retrospective analysis was undertaken of long-term video/EEG recordings from rats with epileptic spasms. The frequency and duration of the ictal events of spasms were quantified.

RESULTS

Rats with a history of epileptic spasms showed impairment on the three behavioral tests, and their scores on the object recognition memory and matching to place water maze tests indicated neocortical involvement in the observed impaired cognition. Analysis of EEG recordings unexpectedly showed that the ictal events of spasms and their accompanying behaviors progressively increased in duration over a 2-week period soon after onset, after which spasm duration plateaued. At the same time, spasm frequency remained unchanged. Soon after spasm onset, ictal events were variable in wave form but became more stereotyped as the syndrome evolved.

SIGNIFICANCE

Our EEG findings are the first to demonstrate progressive ictogenesis for epileptic spasms. Furthermore, in demonstrating cognitive deficits in the tetrodotoxin model, we have met a criterion for an animal model of West syndrome. Animal models will allow in-depth studies of spasm progression's potential role in cognitive regression and may elucidate why early treatment is considered essential for improved neurodevelopmental outcomes in children.

Clinical profile, treatment modalities, and outcomes in patients with infantile spasms: A retrospective study from the United Arab of Emirates (UAE)

BACKGROUND

Infantile spasms (IS) are an epileptic encephalopathy where the prognosis is generally poor, with most patients exhibiting psychomotor retardation or intractable epilepsy. However, it is claimed that early and aggressive treatment is related to better response rate and outcome, especially in patients with idiopathic IS.

OBJECTIVE

To investigate different treatment modalities and outcomes in patients with IS attending a pediatric neurology clinic at a specialized neurology center in Abu Dhabi, United Arab Emirates.

METHODS

Retrospective chart review was done for detailed history, demographic data, etiology, neuro-diagnostic workup, treatment modalities, and the outcomes for all patients diagnosed with IS from September 2014 to September 2019.

RESULTS

Three treatment modalities were identified as 1st line- Prednisolone United Kingdom Infantile Spasms Study (UKISS) (N = 15, 46.8%), Anti-Seizure Medications (ASMs) (N = 12, 37.5%), and Vigabatrin (N = 5, 15.6%). The complete response rate to Vigabatrin as a 1st line treatment showed the highest statistical significance (X² = 7.34, p = 0.007). Patients with idiopathic IS showed a comparable response to treatment to those with symptomatic IS. Additional response to 2nd line treatment with Prednisolone UKISS protocol (25%) and Vigabatrin (15%) was noted in patients who showed partial or no response to the 1st line treatment. None of our patients received Adrenocorticotropic Hormone as treatment. All patients with desirable final outcomes were with idiopathic IS and none were symptomatic.

CONCLUSION

More than a third of our patients showed poor treatment response whenever they were not offered treatment according to the current available protocols. This indicates an urgent need for having a unified treatment protocol that takes into consideration the availability of medications, professional expertise as well as diagnostic workup outside major tertiary care centers in our region.

Status of epileptic spasms: A study of 21 children

OBJECTIVE

We studied cases with long-lasting epileptic spasms (ES) considered as a spasm status analyzing type of epilepsy, epileptic syndrome, etiology, treatment, and outcome in 21 patients.

METHODS

We evaluated the charts of 21 patients seen between June 2006 and July 2017 who met the electroclinical diagnostic criteria of a spasm status. The spasm status was defined as continuous ES lasting 30 min or longer.

RESULTS

The type of ES was mixed in nine patients, flexion in seven, and extension in five. Epileptic spasms were asymmetric in three patients and unilateral in two. They occurred on awakening in all patients, while during sleep they decreased in all and disappeared in three cases. The duration of the spasm status ranged from 40 min to 15 days according to the seizure diaries of patients and video-EEG recordings. Two well-defined subgroups of patients were recognized; the first included patients with West syndrome (WS) and the second other types of severe non-West epilepsy syndromes. The spasm status responded well to oral vigabatrin (VGB) in four patients, oral topiramate (TPM) in three, oral corticosteroids in one, and cannabidiol in another patient. A good response was observed with benzodiazepines in six patients, with phenytoin (PH) in two, and with phenobarbital (PB) in one. Adrenocorticotropic hormone (ACTH) was effective in one patient and the ketogenic diet in two. Prognosis depends on the etiology.

CONCLUSION

In this study we identified patients with WS and other types of severe non-West epilepsy syndromes who had a particular type of long-lasting ES that, in spite of its long duration does not strictly meet the criteria of the International League against Epilepsy (ILAE) classification of status epilepticus, may be considered a spasm status.

Role of Video-EEG in Children

Routine electroencephalogram (EEG) has many limitations, especially the inability to capture reported habitual events in question. A prolonged EEG with synchronized video (video-EEG) overcomes some of these limitations by improving the sensitivity, specificity and the diagnostic yield by attempting to record the habitual events when they are frequent and when indicated. Video-EEG is employed commonly for the diagnosis and classification of epilepsy/epilepsy syndromes, to distinguish between seizures and seizures mimickers, for pre-surgical evaluation and in the management of critically ill children. The duration of recording would vary depending on the indication and frequency of events. Ambulatory EEG is another cost effective and convenient alternative in certain circumstances. However, availability of the machines and expertise, accessibility, affordability and labor intensive nature of the procedure limit widespread use in India. This review explores the role of video-EEG in the management of children with epileptic and non-epileptic paroxysmal events with respect to routine clinical practice in India.

Patterns of Brain Injury in Perinatal Arterial Ischemic Stroke and the Development of Infantile Spasms

INTRODUCTION

Perinatal arterial ischemic stroke (PAIS) underlies approximately 10% of infantile spasms (IS). We aim to identify patterns of brain injury in ischemic stroke that may predispose infants to infantile spasms.

METHODS

Sixty-four perinatal arterial ischemic stroke patients were identified meeting the following inclusion criteria: term birth, magnetic resonance imaging (MRI) showing ischemic stroke or encephalomalacia in an arterial distribution, and follow-up records. Patients who developed infantile spasms (PAIS-IS) were analyzed descriptively for ischemic stroke injury patterns and were compared to a seizure-free control group (PAIS-only). Stroke injury was scored using the modified pediatric ASPECTS (modASPECTS).

RESULTS

The PAIS-IS (n = 9) group had significantly higher modASPECTS than the PAIS-only (n = 16) group (P = .002, Mann-Whitney). A greater proportion of PAIS-IS patients had injury to deep cerebral structures (67%) than PAIS-only (25%).

CONCLUSION

Infarct size was significantly associated with infantile spasms development. Results support theories implicating deep cerebral structures in infantile spasms pathogenesis. This may help identify perinatal arterial ischemic stroke patients at risk of infantile spasms, facilitating more timely diagnosis.

The severe epilepsy syndromes of infancy: A population-based study

OBJECTIVE

To study the epilepsy syndromes among the severe epilepsies of infancy and assess their incidence, etiologies, and outcomes.

METHODS

A population-based cohort study was undertaken of severe epilepsies with onset before age 18 months in Victoria, Australia. Two epileptologists reviewed clinical features, seizure videos, and electroencephalograms to diagnose International League Against Epilepsy epilepsy syndromes. Incidence, etiologies, and outcomes at age 2 years were determined.

RESULTS

Seventy-three of 114 (64%) infants fulfilled diagnostic criteria for epilepsy syndromes at presentation, and 16 (14%) had "variants" of epilepsy syndromes in which there was one missing or different feature, or where all classical features had not yet emerged. West syndrome (WS) and "WS-like" epilepsy (infantile spasms without hypsarrhythmia or modified hypsarrhythmia) were the most common syndromes, with a combined incidence of 32.7/100 000 live births/year. The incidence of epilepsy of infancy with migrating focal seizures (EIMFS) was 4.5/100 000 and of early infantile epileptic encephalopathy (EIEE) was 3.6/100 000. Structural etiologies were common in "WS-like" epilepsy (100%), unifocal epilepsy (83%), and WS (39%), whereas single gene disorders predominated in EIMFS, EIEE, and Dravet syndrome. Eighteen (16%) infants died before age 2 years. Development was delayed or borderline in 85 of 96 (89%) survivors, being severe-profound in 40 of 96 (42%). All infants with EIEE or EIMFS had severe-profound delay or were deceased, but only 19 of 64 (30%) infants with WS, "WS-like," or "unifocal epilepsy" had severe-profound delay, and only two of 64 (3%) were deceased.

SIGNIFICANCE

Three quarters of severe epilepsies of infancy could be assigned an epilepsy syndrome or "variant syndrome" at presentation. In this era of genomic testing and advanced brain imaging, diagnosing epilepsy syndromes at presentation remains clinically useful for guiding etiologic investigation, initial treatment, and prognostication.

Teleneurology based management of infantile spasms during COVID-19 pandemic: A consensus report by the South Asia Allied West syndrome research group

With telehealth services rescuing patients with chronic neurological disorders during the COVID-19 pandemic, there is a need for simplified teleneurology protocols for neurological disorders in children. Infantile spasms is an epileptic encephalopathy where treatment lag is a significant predictor of outcome. It is one such condition where telemedicine can make a remarkable difference when in-person consultations are delayed or are not possible. However, the adverse effect profile of the first-line therapeutic options, the need for frequent follow-up, underdeveloped telemedicine services, lack of a rational protocol, poor awareness about infantile spasms, a lesser level of parental understanding, and scarcity of pediatric neurologists are the major hurdles in developing countries. This paper provides a teleneurology based approach for the management of infantile spasms in developing countries during the COVID-19 pandemic. The cornerstones of this approach include the fundamental principles of management of infantile spasms, decentralization of patient care to local health providers, efforts for improving sensitivity and specificity of diagnosis, early initiation of first-line therapeutic options, and constant motivation of parents and local health providers to be vigilant for therapeutic response, adverse effects of therapy, and infections.

Adrenocorticotropic Hormone Therapy Improved Spasms and Sleep Disturbance in Smith-Magenis Syndrome: A Case Report

Smith-Magenis syndrome (SMS) is a complex disorder characterized by variable mental retardation, sleep disturbances, craniofacial and skeletal anomalies, self-injurious and attention-seeking behaviors, and speech and motor delays. The case of a 14-month-old girl with SMS who was experiencing spasm clusters and sleep disturbances with sleep-wake intervals of 1.5 to 2 h persisting from the neonatal period was examined. The patient's spasms stopped and interictal electroencephalography did not show epileptic discharges after undergoing a high-dose adrenocorticotropic hormone (ACTH) therapy. Moreover, the patient's sleep cycle stabilized 1 month after receiving the ACTH therapy. Dramatic reductions in the patient's self-injurious behaviors were also noted. At 1 year following ACTH treatment, the patient's improved sleep was maintained. High-dose ACTH treatment was considered to contribute to the normal adaptation of the hypothalamic-pituitary-adrenal axis by regulating the release of corticotropin-releasing hormone, resulting in improvement of the patient's infantile spasms and sleep disturbances.

West syndrome: a comprehensive review

Since its first clinical description (on his son) by William James West (1793–1848) in 1841, and the definition of the classical triad of (1) infantile spasms; (2) hypsarrhythmia, and (3) developmental arrest or regression as “West syndrome”, new and relevant advances have been recorded in this uncommon disorder. New approaches include terminology of clinical spasms (e.g., infantile (IS) vs. epileptic spasms (ES)), variety of clinical and electroencephalographic (EEG) features (e.g., typical ictal phenomena without EEG abnormalities), burden of developmental delay, spectrum of associated genetic abnormalities, pathogenesis, treatment options, and related outcome and prognosis. Aside the classical manifestations, IS or ES may present with atypical electroclinical phenotypes (e.g., subtle spasms; modified hypsarrhythmia) and may have their onset outside infancy. An increasing number of genes, proteins, and signaling pathways play crucial roles in the pathogenesis. This condition is currently regarded as a spectrum of disorders: the so-called infantile spasm syndrome (ISs), in association with other causal factors, including structural, infectious, metabolic, syndromic, and immunologic events, all acting on a genetic predisposing background. Hormonal therapy and ketogenic diet are widely used also in combination with (classical and recent) pharmacological drugs. Biologically targeted and gene therapies are increasingly studied. The present narrative review searched in seven electronic databases (primary MeSH terms/keywords included West syndrome, infantile spasms and infantile spasms syndrome and were coupled to 25 secondary clinical, EEG, therapeutic, outcomes, and associated conditions terms) including MEDLINE, Embase, Cochrane Central, Web of Sciences, Pubmed, Scopus, and OMIM to highlight the past knowledge and more recent advances.

The evolving indications of KD therapy

Despite the rapid increase of clinical and basic-science knowledge on ketogenic diet therapies over the past years, it has not always been easy to determine the adequate indications of this treatment. Over the nearly 100 years of use, from being a last resource in the therapeutic algorithm, the diet has become one of the four main treatments for patients with difficult-to-control epilepsy together with antiepileptic drugs, surgery, and vagus nerve stimulation. The use of the diet has also changed. The current paper will briefly discuss the history of the diet together with a review of the literature regarding its most important indications and how they have evolved. The concept of the importance of defining the type of seizure, type of syndrome, and etiology in the selection of patients and timing of diet initiation has been gaining importance. This paper explores how the indications of the diet changed together with the shifting focus of epilepsy teams towards its use in different types of epilepsy and epilepsy syndromes and according to etiologies and as an alternative option in refractory and superrefractory status epilepticus.

Developmental profile at initial presentation in children with infantile spasms

AIM

To describe the baseline developmental profile and influence of clinical and demographic factors on the developmental skills of infants diagnosed with infantile spasms.

METHOD

Ninety-five infants (55 males, 40 females) newly diagnosed with infantile spasms were recruited for a cross-sectional, longitudinal study. All infants underwent Bayley Scales of Infant and Toddler Development assessments in the cognitive, receptive communication, expressive communication, and fine and gross motor developmental domains; they also underwent visual, auditory, and social behaviour assessments. Infants were categorized as 'early' (<6mo) or 'late' (≥6mo) presenters; if presented within 28 days, this was considered as 'early presentation', whereas a delay greater than 28 days was considered as a 'delay in presentation'. Antenatal, perinatal, and postnatal risk factors were identified.

RESULTS

Over 90% of infants showed impairment in all domains, with the majority having severe delay; 99% showed cognitive impairment. Delayed presentation was significantly associated with receptive communication delay (odds ratio [OR]=5.35; 95% confidence interval [CI]=1.05-27.32). Onset at 6 months or less influenced auditory (OR=2.8; 95% CI=1.16-6.8) and visual (OR=3.03; 95% CI=1.22-7.57) behaviours. Neonatal infections impacted both receptive (OR=1.12; 95% CI=1.04-1.2) and expressive communication (OR=1.08; 95% CI=1.02-1.14) delay. Neonatal seizures significantly influenced visual, auditory, and social impairments. Expressive communication and gross motor development shared common perinatal risk factors.

INTERPRETATION

Adverse developmental status at presentation, associated with delayed presentation and neonatal risk factors should alert clinicians to the surveillance of at-risk infants and seek out timely interventions.

WHAT THIS PAPER ADDS

Ninety per cent of infants showed impaired cognitive, communication, and motor skills at presentation. Visual, auditory, and social behaviour impairments were significantly associated with perinatal risks. Visual, auditory, and social behaviour impairments were significantly associated with neonatal seizures.

Hypsarrhythmia is associated with widespread, asymmetric cerebral hypermetabolism

PURPOSE

Hypsarrhythmia is the interictal EEG pattern most often associated with infantile spasms. We set out to evaluate the metabolic impact of hypsarrhythmia among patients with infantile spasms by contrasting regional cerebral metabolic activity among children with and without hypsarrhythmia.

METHODS

Patients with video-EEG confirmed infantile spasms who underwent simultaneous interictal EEG and FDG-PET as part of a surgical evaluation were retrospectively identified. Pons-normalized relative cerebral metabolic activity (RCA) was ascertained in 18 cortical and 6 subcortical pre-specified regions of interest (ROIs).

RESULTS

We identified 63 patients with infantile spasms who underwent simultaneous EEG/PET, including children with hypsarrhythmia (n = 9), high-voltage EEG background (n = 20), and multifocal independent spike discharges (MISD) (n = 34). Among them, a putative epileptogenic zone was identified within the left-hemisphere only (n = 27), right-hemisphere only (n = 20), or assumed to be bilateral (n = 16). After adjustment for age at PET, the presence of hypsarrhythmia was associated with hypermetabolism in 11 of 18 cortical ROI's. After adjustment for lateralized epileptogenic zones, the association between hypsarrhythmia and hypermetabolism was generally stronger within the left hemisphere.

CONCLUSION

Hypsarrhythmia is associated with widespread-and curiously left more than right-elevations in pons-normalized RCA, which is not evident on routine clinical review of individual PET studies. This study suggests that hypsarrhythmia may be a quasi-ictal phenomenon based on widespread and usually bilateral cortical hypermetabolism.

Latitudinal differences on the global epidemiology of infantile spasms: systematic review and meta-analysis

BACKGROUND

Infantile spasms represent the catastrophic, age-specific seizure type associated with acute and long-term neurological morbidity. However, due to rarity and heterogenous determination, there is persistent uncertainty of its pathophysiological and epidemiological characteristics. The purpose of the current study was to address a historically suspected latitudinal basis of infantile spasms incidence, and to interrogate a geographical basis of epidemiology, including the roles of latitude and other environmental factors, using meta-analytic and -regression methods.

METHODS

A systematic search was performed in Ovid MEDLINE and Embase for primary reports on infantile spasms incidence and prevalence epidemiology.

RESULTS

One thousand fifteen studies were screened to yield 54 eligible publications, from which 39 incidence figures and 18 prevalence figures were extracted. The pooled incidence was 0.249 cases/1000 live births. The pooled prevalence was 0.015 cases/1000 population. Univariate meta-regression determined a continental effect, with Europe demonstrating the highest onset compared from Asia (OR = 0.51, p = 0.004) and from North America (OR = 0.50, p = 0.004). Latitude was also positively correlated with incidence globally (OR = 1.02, p < 0.001). Sub-analyses determined a particularly elevated Scandinavian incidence compared to the rest of world (OR = 1.88, p < 0.001), and lack of latitudinal effect with Scandinavian exclusion (p = 0.10). Metrics of healthcare quality did not predict incidence. Multiple meta-regression determined that latitude was the key predictor of incidence (OR = 1.02, p = 0.001).

CONCLUSIONS

This is the first systematic epidemiological study of infantile spasms. Limitations included lack of Southern hemispheric representation, insufficient study selection and size to support some sub-continental analyses, and lack of accessible ethnic and healthcare quality data. Meta-analyses determined a novel, true geographical difference in incidence which is consistent with a latitudinal and/or ethnic contribution to epileptogenesis. These findings justify the establishment of a global registry of infantile spasms epidemiology to promote future systematic studies, clarify risk factors, and expand understanding of the pathophysiology.

West Syndrome: A Review and Guide for Paediatricians

West syndrome (WS), also known as infantile spasms, occurs in infancy with a peak between 4 and 7 months. Spasms, neurodevelopmental regression and hypsarrhythmia on electroencephalogram (EEG) basically define WS. The International League Against Epilepsy commission classifies the aetiologies of WS into genetic, structural, metabolic and unknown. Early diagnosis and a shorter lag time to treatment are essential for the overall outcome of WS patients. These goals are feasible with the addition of brain magnetic resonance imaging (MRI) and genetic and metabolic testing. The present work analysed the medical literature on WS and reports the principal therapeutic protocols of its management. Adrenocorticotropic hormone (ACTH), vigabatrin (VGB) and corticosteroids are the first-line treatments for WS. There is no unique therapeutic protocol for ACTH, but most of the evidence suggests that low doses are as effective as high doses for short-term treatment, which is generally 2 weeks followed by dose tapering. VGB is generally administered at doses from 50 to 150 mg/kg/day, but its related retinal toxicity, which occurs in 21-34% of infants, is most frequently observed when treatment periods last longer than 6 months. Among corticosteroids, a treatment of 14 days of oral prednisolone (40-60 mg/day) has been considered effective and well tolerated. Considering that an early diagnosis and a shorter lag time to treatment are essential for successful outcomes in these patients, further studies on efficacy of the different therapeutic approaches with evaluation of final outcome after cessation of therapy are needed.

The impact of hypsarrhythmia on infantile spasms treatment response: Observational cohort study from the National Infantile Spasms Consortium

OBJECTIVE

The multicenter National Infantile Spasms Consortium prospective cohort was used to compare outcomes and phenotypic features of patients with infantile spasms with and without hypsarrhythmia.

METHODS

Patients aged 2 months to 2 years were enrolled prospectively with new-onset infantile spasms. Treatment choice and categorization of hypsarrhythmia were determined clinically at each site. Response to therapy was defined as resolution of clinical spasms (and hypsarrhythmia if present) without relapse 3 months after initiation.

RESULTS

Eighty-two percent of patients had hypsarrhythmia, but this was not associated with gender, mean age, preexisting developmental delay or epilepsy, etiology, or response to first-line therapy. Infants with hypsarrhythmia were more likely to receive standard treatment (adrenocorticotropic hormone, prednisolone, or vigabatrin [odds ratio (OR) 2.6, 95% confidence interval (CI) 1.4-4.7] and preexisting epilepsy reduced the likelihood of standard treatment (OR 3.2, 95% CI 1.9-5.4). Hypsarrhythmia was not a determinant of response to treatment. A logistic regression model demonstrated that later age of onset (OR 1.09 per month, 95% CI 1.03-1.15) and absence of preexisting epilepsy (OR 1.7, 95% CI 1.06-2.81) had a small impact on the likelihood of responding to the first-line treatment. However, receiving standard first-line treatment increased the likelihood of responding dramatically: vigabatrin (OR 5.2 ,95% CI 2-13.7), prednisolone (OR 8, 95% CI 3.1-20.6), and adrenocorticotropic hormone (ACTH; OR 10.2, 95% CI 4.1-25.8) .

SIGNIFICANCE

First-line treatment with standard therapy was by far the most important variable in determining likelihood of response to treatment of infantile spasms with or without hypsarrhythmia.

A practical, simple, and useful method of categorizing interictal EEG features in children

We introduce a simple scheme of categorizing interictal EEG in patients with pediatric epilepsy. Five patterns of EEG can be determined by using 2 interictal EEG domains: organization of the background activity and a morphology/topography of epileptiform discharges. These patterns relate to commonly recognized categories of pediatric epilepsy: familial epilepsies, genetic generalized epilepsies, self-limited epilepsies, epilepsies with encephalopathy, and focal structural epilepsies. Each group has distinguishable clinical presentations, inheritance patterns, and outcomes. This categorization may be a useful educational tool; it may also guide decisions about further testing and management.

Efficacy and tolerability of high-dose prednisone in Chinese children with infantile spasms

OBJECTIVES

The aim of this study is to preliminarily evaluate the clinical efficacy and safety of high-dose prednisone in the treatment of infantile spasms (IS) in China, and to provide additional choice of the therapy of IS.

METHODS

Twenty patients aged 3-53 months with IS were collected in the Department of Neurology of Jiangxi Children's Hospital from May in 2011 to December in 2012, who were placed on high-dose prednisone (took prednisone tablet of 10mg four times a day) for 2 weeks during admission to our hospital. The assessment of spasms seizure and video-EEG monitoring were preformed before treatment and after 2 weeks and the end of treatment of the regimen (7 weeks), respectively. All of the children were followed-up for 2-14 months.

RESULTS

Among 20 cases, there were 16 cases (80.0%) with complete cessation of spasms after 2 weeks and 13 cases (65.0%) after 7 weeks. There were 19 cases with typical or modified hypsarrhythmia in 20 cases. No matter after 2 or 7 weeks, there were 12 cases showed complete resolution of hypsarrhythmia and 7 cases with only a partial remission of hypsarrhythmia. After a follow-up of 2-14 months, the longest spasm-free interval was 14 months and the shortest one was 11 days. Six cases relapsed in different periods, and the relapse rate was 35.3%. Amongst the main adverse events, there were Cushing's symptoms in 15 cases (75.0%), irritability in 8 cases (40.0%), drosiness in 3 cases (15.0%), high blood pressure in 3 cases (15.0%), and infections in 8 cases (40.0%), but no one stopped the treatment because of the adverse reactions.

CONCLUSION

In total, high-dose prednisone was effective and well-tolerated in children with IS in China. Maybe the regimen will become a new choice in the treatment of IS.

Infantile spasms syndrome, West syndrome and related phenotypes: what we know in 2013

The current spectrum of disorders associated to clinical spasms with onset in infancy is wider than previously thought; accordingly, its terminology has changed. Nowadays, the term Infantile spasms syndrome (ISs) defines an epileptic syndrome occurring in children younger than 1 year (rarely older than 2 years), with clinical (epileptic: i.e., associated to an epileptiform EEG) spasms usually occurring in clusters whose most characteristic EEG finding is hypsarrhythmia [the spasms are often associated with developmental arrest or regression]. The term West syndrome (WS) refers to a form (a subset) of ISs, characterised by the combination of clustered spasms and hypsarrhythmia on an EEG and delayed brain development or regression [currently, it is no longer required that delayed development occur before the onset of spasms]. Less usually, spasms may occur singly rather than in clusters [infantile spasms single-spasm variant (ISSV)], hypsarrhythmia can be (incidentally) recorded without any evidence of clinical spasms [hypsarrhythmia without infantile spasms (HWIS)] or typical clinical spasms may manifest in absence of hypsarrhythmia [infantile spasms without hypsarrhythmia (ISW)]. There is a growing evidence that ISs and related phenotypes may result, besides from acquired events, from disturbances in key genetic pathways of brain development: specifically, in the gene regulatory network of GABAergic forebrain dorsal-ventral development, and abnormalities in molecules expressed at the synapse. Children with these genetic associations also have phenotypes beyond epilepsy, including dysmorphic features, autism, movement disorders and systemic malformations. The prognosis depends on: (a) the cause, which gives origin to the attacks (the complex malformation forms being more severe); (b) the EEG pattern(s); (c) the appearance of seizures prior to the spasms; and (d) the rapid response to treatment. Currently, the first-line treatment includes the adrenocorticotropic hormone ACTH and vigabatrin. In the near future the gold standard could be the development of new therapies that target specific pathways of pathogenesis. In this article we review the past and growing number of clinical, genetic, molecular and therapeutic discoveries on this expanding topic.

Epilepsy with myoclonic atonic seizures: an electroclinical study of 69 patients

Epilepsy with myoclonic-atonic seizures is characterized by myoclonic-atonic, absence, tonic-clonic, and eventually tonic seizures, appearing in previously normal children at ages 18-60 months. We analyzed the electroclinical features, treatment, and outcome of 69 patients with myoclonic-atonic seizures; these patients were followed between 1990 and 2012 at the Juan P. Garrahan Pediatric Hospital, Buenos Aires, Argentina. No structural or metabolic etiology was identified. Based on the electroclinical features and evolution, two groups could be distinguished. The first group of 39 patients with myoclonic and myoclonic-atonic seizures with or without generalized tonic-clonic seizures and absences associated with generalized spike- and polyspike-and-wave paroxysms had excellent prognoses. The second group of 30 patients had myoclonic jerks and myoclonic-atonic seizures associated with other seizure types including tonic seizures; some had myoclonic status epilepticus and cognitive deterioration. The interictal EEG showed frequent generalized spike- and polyspike-and-wave paroxysms. In 16 patients, the seizures remitted within 3.6 years. The two groups were distinguished in retrospect, when enough time had elapsed to evaluate cognitive deterioration and different seizure types. In conclusion, epilepsy with myoclonic atonic seizures is an epileptic syndrome with a broad clinical spectrum and variable prognosis.

Genetic and biologic classification of infantile spasms

Infantile spasms constitute an age-dependent epilepsy, highly associated with cognitive impairment, autism, and movement disorders. Previous classification systems focused on a distinction between symptomatic and cryptogenic etiologies, and have not kept pace with recent discoveries of mutations in genes in key pathways of central nervous system development in patients with infantile spasms. Children with certain genetic syndromes are much likelier to manifest infantile spasms, and we review the literature to propose a genetic classification of these disorders. Children demonstrating genetic associations with infantile spasms also manifest phenotypes beyond epilepsy that may be explained by recent advances in the understanding of underlying biological mechanisms. Therefore we propose a biologic classification of genes highly associated with infantile spasms, and articulate models for infantile spasms pathogenesis based on those data. The two best described pathways of pathogenesis involve abnormalities in the gene regulatory network of gamma-aminobutyric acidergic forebrain development and abnormalities in molecules expressed at the synapse. These genetic and biologic classifications are flexible, and they should encourage much needed progress in syndrome recognition, clinical genetic testing, and the development of new therapies targeting specific pathways of pathogenesis.