Infantile spasms

Response to magnesium sulfate and adrenocorticotropic hormone combination therapy for infantile spasms with failed first-line treatments

Importance

Infantile spasm (IS) is a kind of refractory epilepsy. The first-line treatments for IS are adrenocorticotropic hormone (ACTH), oral corticosteroids, and vigabatrin.

Objective

This study aimed to evaluate the efficacy of magnesium sulfate and ACTH (MgSO4+ACTH) combination therapy in patients with IS who failed first-line treatments.

Methods

In this retrospective study, the clinical data of patients with IS who failed first-line treatments were collected in the Chinese PLA General Hospital. Patients received MgSO4+ACTH combination therapy after first-line treatments failed. The course of treatments was 2 weeks. The therapeutic dose of ACTH and MgSO4 was 2.5 U·kg-1·d-1 and 0.25 g·kg-1·d-1, respectively.

Results

A total of 229 patients with IS who failed the first-line treatments were collected. At the end of the MgSO4+ACTH combination treatment, the seizure-free rate was 48.5% (111/229), and the resolution of hypsarrhythmia on electroencephalogram (EEG) was 72.1% (165/229). About 21.4% (49/229) of patients showed side effects, including infectious diseases, hypokalemia, and diarrhea.

Interpretation

For patients with IS who failed first-line treatments, in terms of the seizure-free rate and resolution of hypsarrhythmia on EEG, MgSO4+ACTH combination therapy can be considered.

Comparison of Efficacy and Safety of Low- Versus High-Dose Oral Prednisolone in Infantile Spasm (IS): An Open Label Randomized Controlled Trial at the Children’s Hospital & Institute of Child Health, Multan, Pakistan

Background: Infantile spasm (IS) is an epileptic syndrome characterized by epileptic spasms, hypsarrhythmia on electroencephalography (EEG), and high risk of neurodevelopmental regression. This study was done to compare the efficacy and safety of the high versus the usual dose in children with IS.

Methodology: This open label randomized controlled trial was conducted at Department of Pediatric Neurology, The Children’s Hospital & Institute of Child Health, Multan, Pakistan, from January 1, 2020 to December 31, 2020. A total of 62 children (31 in each group) aged three months to two years presenting with epileptic spasms (at least one cluster per day) with EEG evidence of hypsarrhythmia were included. All 62 children were randomized to receive either high-dose prednisolone (10mg per dose four times a day) or the usual-dose prednisolone (2mg/kg/day thrice a day) for 14 days. Primary outcome measure was noted in terms of proportion of children who achieved complete, partial, or no response. Secondary outcome measure was proportion of children with adverse effects.

Results: In a total of 62 children, there were 34 (54.8%) male. Overall, mean age was noted to be 9.1±3.4 months. The most common etiology of IS was noted to be hypoxic-ischemic encephalopathy (HIE) in 28 children (45.2%). Significantly better clinical efficacy was reported in high-dose prednisolone group when compared to low-dose prednisolone cases as complete response, partial response and no response were noted in nine (29.0%), eight (25.8%), and 14 (45.2%) patients of low-dose group versus 18 (58.1%), eight (25.8%), and five (16.1%) patients in high-dose group, respectively (p=0.0265). Weight gain was the most frequently reported adverse effects noted in 11 (17.7%) cases. Overall, no statistically significant difference in the frequency of adverse effects (p=0.9573).

Conclusion: In comparison to low-dose prednisolone, high-dose prednisolone was found to be significantly more efficacious among cases of IS. Adverse effect in both treatment groups were relatively low and similar.

High-Dose Prednisolone for Treatment of Infantile Spasms After Presumed Perinatal Stroke

ABSTRACT

BACKGROUND: High-dose prednisone and prednisolone have been increasingly studied as a lower-cost alternative to adrenocorticotropic hormone for the treatment of infantile spasms, but this treatment has not been well studied in children with infantile spasms due to perinatal stroke. METHODS: We identified a girl with new-onset infantile spasms due to presumed perinatal left middle cerebral artery stroke seen in our hospital's pediatric stroke clinic in 2019. RESULTS: This girl developed infantile spasms at 9 months old. She had right hemiplegic cerebral palsy due to her perinatal stroke but had been otherwise previously healthy. Modified hypsarrhythmia was confirmed on prolonged video-electroencephalography. High-dose prednisolone at 8 mg/kg per day was initiated on the sixth day of spasms. She was treated with this dose for 2 weeks and then tapered over 5 weeks. The girl became seizure-free after receiving her first dose of prednisolone and experienced no significant adverse effects during therapy. Routine electroencephalography after completion of prednisolone taper confirmed resolution of modified hypsarrhythmia and no epileptiform discharges. She continued to make excellent development progress during and after treatment. CONCLUSION: This case suggests high-dose prednisolone could be considered for first-line therapy for children with infantile spasms due to perinatal stroke; further study is needed.

Neutrophil to lymphocyte rate and serum prealbumin maybe predictors for abnormal high blood pressure caused by adrenocorticotropic hormone therapy in children with epileptic spasms: two cases report

Epileptic spasms are a catastrophic form of epilepsy. When epileptic spasms occur under 2-year-old, they may be also called “infantile spasms”. Adrenocorticotropic hormone (ACTH) is recommended as first line intervention for the treatment of epileptic spasms without tuberous sclerosis complex. The chief risks of ACTH therapy are immunosuppression and hypertension. We reported rare cases of abnormal high blood pressure in two male epileptic spasms patients during ACTH therapy. Both patients’ blood pressure reached a high blood pressure stage 2 on the 9th day and 10th day of ACTH treatment, respectively. The blood pressure returned to normal range after the drug dosage was reduced or stopped. The lower level of neutrophil%, neutrophil count, and a higher level of lymphocyte%, lymphocyte count and prealbumin than normal range were observed in both patients before ACTH therapy. The neutrophil to lymphocyte rate might be a predictor for high blood pressure among patients treated with ACTH. The rates of both patients were under 0.50 (0.42 for Case 1 and 0.17 for Case 2). We reported the documented cases in two Chinese pediatric patients who suffered from epileptic spasms treated with ACTH resulted in abnormal high blood pressure, which could be predicted by using neutrophil to lymphocyte rate. We also mentioned serum prealbumin might be another predictor. More clinical data is required to elucidate the relationship between serum prealbumin level and blood pressure.

Novel West syndrome candidate genes in a Chinese cohort

AIMS

West syndrome (WS) is a classic form of early infantile epileptic encephalopathy (EIEE) characterized by tonic spasms with clustering, arrest of psychomotor development, and hypsarrhythmia on electroencephalography. Genetic defects play a critical role in the pathology of WS, and 54 EIEE genes have been identified till date. This study was designed to uncover new candidate genes for West syndrome.

METHODS

In this study, we recruited 56 Chinese families with WS of unknown etiology. Whole exome sequencing (WES) was performed to identify Mendelian inheritance rare or novel variants. The association between candidate genes and WS was analyzed from many aspects, including recurrent genes in patients, predicted variant effect on genes, human tolerance to deficient genes, gene expression in the nervous system, coexpression with EIEE genes, mutual interaction with known EIEE proteins, genes related to ion channel or fragile X mental retardation protein function, and mouse models with manifestation of seizures. Genes with supporting evidence from those aspects were defined as highlight candidate genes.

RESULTS

Whole exome sequencing identified 112 candidate variants in 89 genes. Among the candidate genes, 33 were autosomal dominant, 22 were autosomal recessive, and 34 were X-linked. Complex bioinformatic analysis revealed 17 highlight candidate genes: ATP2A2, CD99L2, CLCN6, CYFIP1, CYFIP2, GNB1, GPT2, HUWE1, KMT2D, MYO18A, NOS3, RYR1, RYR2, RYR3, TAF1, TECTA, and UBA1. The majority of highlight candidate genes are calcium-signaling pathway and mental retardation genes.

CONCLUSIONS

This is the first WES study of Chinese WS patients with unknown etiology. This combination of phenotypic and genomic data will enable further testing to elucidate mechanisms underlying the pathogenesis of WS.

Why Are Children With Epileptic Encephalopathies Encephalopathic?

The epileptic encephalopathies are devastating conditions characterized by frequent seizures, severely abnormal electroencephalograms (EEGs), and cognitive slowing or regression. The cognitive impairment in the epileptic encephalopathies may be more concerning to the patient and parents than the epilepsy itself. There is increasing recognition that the cognitive comorbidity can be both chronic, primarily due to the underlying etiology of the epilepsy, and dynamic or evolving because of recurrent seizures, interictal spikes, and antiepileptic drugs. Much of scholars' understanding of the neurophysiological underpinnings of cognitive dysfunction in the epileptic encephalopathies comes from rodent studies. Frequent seizures and interictal EEG discharges in rats lead to considerable spatial and social-cognitive deficits. Paralleling these cognitive deficits are dyscoordination of dynamic neural activity within and between the neural networks that subserve normal cognitive processes.

Diagnosing infantile spasms: Accuracy of the internet

Infantile spasms, one of the catastrophic epilepsies, can be a diagnostic challenge since the clinical manifestations may be subtle and may mimic benign conditions. Because of the rarity of the condition, primary care physicians and pediatricians may never see a case of infantile spasms during their career and may be unfamiliar with the seizure semiology. This is a serious issue since there is evidence that early diagnosis and treatment may improve outcome. Patients and families are increasingly using the internet more than their physician as a source of medical information about epilepsy. The reliance on using the internet for diagnostic information raises concerns about the accuracy of posted material that has not undergone professional review. To assess the quality of information being obtained about infantile spasms, we reviewed written and video content addressing infantile spasms on the internet. A total of 135 websites and 156 videos were reviewed for accuracy. Using the search terms Infantile Spasms and West Syndrome, we report that the majority of the written and video information provided was accurate and provided important and pertinent information. We conclude that internet searches provide accurate and pragmatic information about infantile spasms that has the potential for reducing the delay between the onset of the spasms and medical intervention.

Interictal epileptiform activity and autism

Many individuals with autism have epileptiform discharges on their EEG without having definite clinical seizures. The clinical significance of epileptiform activity in patients with autism is controversial. Some consider it an epiphenomenon of the underlying condition that should be ignored, and others believe that frequent spikes may contribute to the cognitive impairment and advocate treatment. Several studies have reported variable rates of epileptiform activity and variable response to treatment. There is an urgent need to conduct controlled clinical trials to assess the true incidence of epileptiform activity in children with autism, develop a risk assessment model, and study the effectiveness of treatment. This article is part of a Special Issue entitled "Autism and Epilepsy".

Intellectual development before and after the onset of infantile spasms: a controlled prospective longitudinal study in tuberous sclerosis

OBJECTIVE

Infantile spasms (IS) have long been suspected to be a risk factor for impairment in intellectual development, but there are no controlled, prospective longitudinal data in well-characterized conditions to confirm this suspicion. We tested the hypothesis in a longitudinal study of children with tuberous sclerosis (TS), who have a high risk of developing IS.

METHODS

Eleven infants with TS were recruited and studied longitudinally using the Mullen Scales of Early Learning. Seizure histories were assessed using a structured parent interview and by review of medical notes. Intellectual development was examined in relation to the onset and length of exposure to IS and other types of seizures.

RESULTS

Six children developed IS and five children developed other types of seizure disorders. Among those that developed IS, estimated mean IQ dropped significantly (nonparametric test for trend p = 0.002) from 92 (prior to onset of spasms) to 73 (after exposure to IS for a month or less) and 62 (after exposure to IS for more than a month). By contrast, there was no significant drop in estimated IQ among the five infants exposed to other types of seizure disorders (nonparametric test for trend p = 0.9). All six children exposed to infantile spasms developed clinically significant intellectual impairment.

SIGNIFICANCE

These data provide the first clear evidence of clinically significant, dose dependent, impairment in intellectual development following exposure to infantile spasms. The mechanisms underlying this developmental impairment and methods for preventing it require in depth study.

Prenatal corticosteroids modify glutamatergic and GABAergic synapse genomic fabric: insights from a novel animal model of infantile spasms

Prenatal exposure to corticosteroids has long-term postnatal somatic and neurodevelopmental consequences. Animal studies indicate that corticosteroid exposure-associated alterations in the nervous system include hypothalamic function. Infants with infantile spasms, a devastating epileptic syndrome of infancy with characteristic spastic seizures, chaotic irregular waves on interictal electroencephalogram (hypsarhythmia) and mental deterioration, have decreased concentrations of adrenocorticotrophic hormone (ACTH) and cortisol in cerebrospinal fluid, strongly suggesting hypothalamic dysfunction. We have exploited this feature to develop a model of human infantile spasms by using repeated prenatal exposure to betamethasone and a postnatal trigger of developmentally relevant spasms with NMDA. The spasms triggered in prenatally primed rats are more severe compared to prenatally saline-injected ones and respond to ACTH, a treatment of choice for infantile spasms in humans. Using autoradiography and immunohistochemistry, we have identified a link between the spasms in our model and the hypothalamus, especially the arcuate nucleus. Transcriptomic analysis of the arcuate nucleus after prenatal priming with betamethasone but before trigger of spasms indicates that prenatal betamethasone exposure down-regulates genes encoding several important proteins participating in glutamatergic and GABAergic transmission. Interestingly, there were significant sex-specific alterations after prenatal betamethasone in synapse-related gene expression but no such sex differences were found in prenatally saline-injected controls. A pairwise relevance analysis revealed that, although the synapse gene expression in controls was independent of sex, these genes form topologically distinct gene fabrics in males and females and these fabrics are altered by betamethasone in a sex-specific manner. These findings may explain the sex differences with respect to both normal behaviour and the occurrence and severity of infantile spasms. Changes in transcript expression and their coordination may contribute to a molecular substrate of permanent neurodevelopmental changes (including infantile spasms) found after prenatal exposure to corticosteroids.

Prenatal stress exposure hypothesis for infantile spasms

Infantile spasms (IS) are an age-specific epileptic syndrome associated with diverse etiological factors. In recent years, several hypotheses and animal models have been proposed to explain the pathogenesis of IS, but none has elucidated the pathophysiology of IS. In the current case-control study, prenatal stress degree was identified to be higher among the mothers of IS patients than those among the control group. The onset risk of IS increased with the degree of prenatal stress within a certain range. We have recently exposed pregnant rats to forced cold swimming and have given intraperitoneal injection of N-methyl-d-aspartate (NMDA) to rat pups with prenatal stress exposure. Prenatal stress exposure was found to alter the hormonal levels and neurotransmitter receptor expression of developing rats, sensitizing rat pups to develop NMDA-induced spasms and rendering the spasms to be sensitive to adrenocorticotropic hormone therapy. The studies above indicate that prenatal stress plays an important role in the onset of IS. Based on previous hypotheses and the current findings, we propose a prenatal stress exposure hypothesis for IS (also called Zou's hypothesis).

Safety and efficacy of vigabatrin for the treatment of infantile spasms

In 2009, vigabatrin became the first FDA approved medication for the treatment of infantile spasms in the United States. There are few well-designed prospective studies comparing the drug to placebo or other modalities used in the treatment of infantile spasms. The available data have demonstrated that vigabatrin is efficacious in the treatment of infantile spasms regardless of underlying etiology, but that it is particularly beneficial in patients with a diagnosis of tuberous sclerosis. Adrenocorticotropic hormone (ACTH), the only other medication with robust efficacy data, has been used as first line therapy for infantile spasms associated with other etiologies, and in general controls spasms sooner than vigabatrin, though relapse is common with both therapies. Vigabatrin is generally well tolerated. However, use has been associated with permanent loss of peripheral vision in some patients. In children with tuberous sclerosis, vigabatrin should be considered as initial therapy for infantile spasms. It is a viable alternative for patients with suboptimal response, contraindications or intolerance to ACTH.

Pediatric epileptology

Challenges facing children with epilepsy are understanding the neurobiology of pharmacoresistance of epileptic encephalopathies and the development of effective surgical treatment options for those with "non-lesional" epilepsy. Although, understanding the genetics of childhood epilepsy has advanced, an effective treatment intervention has not occurred. Recently, understanding the neurobiology of hamartin and tuberin in the development of epilepsy and cognitive impairment associated with tuberous sclerosis complex allowed the development of sirolimus and everolimus to be used in human clinical trials. In spite of these breakthroughs a large number of children are likely to be outside the scope of interventional therapies. For such patients the burden of seizures is onerous and psycho-social consequences debilitating. Surgical resective options are often limited by the lack of a well defined epileptic lesion. Co-registered synthesis of advanced functional, structural and electrographic seizure onset allows identification of a focus in patients thought to have "non-lesional" epilepsy. Developments of a Pipeline for prospective data sharing are likely to increase understanding and validation of the epileptogenic zone and offer the hope of seizure freedom. Two outstanding young investigators provide a review of their exciting research and its implications in pediatric epilepsy.

Validation of the rat model of cryptogenic infantile spasms

PURPOSE

To determine whether a new model of cryptogenic infantile spasms consisting of prenatal priming with betamethasone and postnatal trigger of spasms by N-methyl-D-aspartate (NMDA) responds to chronic adrenocorticotropic hormone (ACTH) treatment, and has electroencephalography (EEG) signature, efficacy of treatments, and behavioral impairments similar to those in human infantile spasms.

METHODS

Rats prenatally primed with betamethasone on gestational day 15 were used. Spasms were triggered with NMDA between postnatal days (P) 10 and 15 in a single session or in multiple sessions in one subject. The expression of spasms was compared to prenatally saline-injected controls. Effects of relevant treatments (ACTH, vigabatrin, methylprednisolone, rapamycin) were determined in betamethasone-primed rats. In the rats after spasms, behavioral evaluation was performed in the open field and elevated plus maze on P20-22.

KEY FINDINGS

NMDA at P10-15 (the rat "infant" period) triggers the spasms significantly earlier and in greater numbers in the prenatal betamethasone-exposed brain compared to controls. Similar to human condition, the spasms occur in clusters. Repeated trigger of spasms is associated with ictal EEG electrodecrements and interictal large-amplitude waves, a possible rat variant of hypsarrhythmia. Chronic ACTH treatment in a randomized experiment, and chronic pretreatment with methylprednisolone significantly suppress the number of spasms similar to the human condition. Pretreatment with vigabatrin, but not rapamycin, suppressed the spasms. Significant behavioral changes occurred following multiple bouts of spasms.

SIGNIFICANCE

The model of infantile spasms has remarkable similarities with the human condition in semiology, EEG, pharmacologic response, and long-term outcome. Therefore, the model can be used to search for novel and more effective treatments for infantile spasms.

Seizures and intellectual outcome: clinico-radiological study of 30 Egyptian cases of tuberous sclerosis complex

BACKGROUND AND OBJECTIVES

Tuberous sclerosis complex (TSC) is a multi-systemic disorder that involves primarily CNS, skin, kidney and heart. The aim of this study is to determine whether seizures type, interictal EEGs and tubers burden in MRI are correlated to seizure and intellectual outcome, and to identify the clinical risk factors for mental retardation and developing autism in these patients.

METHODS

This was a prospective study that was conducted on 30 Egyptian children with tuberous sclerosis complex (TSC), diagnosed according to the criteria of National Institutes of Health consensus conference revised the diagnostic criteria for TSC. All patients underwent clinical and psychometric evaluation, interictal EEG, and MRI brain.

RESULTS AND CONCLUSIONS

We found that poor intellectual outcome is related to early onset of seizures, infantile spasms, severely epileptogenic EEG findings and tuber burden on the Left side. Autistic behavior is related to seizure type (more with infantile spasms), severely epileptogenic EEG findings, frontal location of tubers and higher number of tubers (>8).

Topiramate in the new generation of drugs: efficacy in the treatment of alcoholic patients

Predicated upon a neuropharmacological conceptual model, there is now solid clinical evidence to support the efficacy of topiramate for the treatment of alcohol dependence. Topiramate treatment can be initiated whilst the alcohol-dependent individual is still drinking - just when crisis intervention is most likely to be needed by a patient with or without his or her family asking the health practitioner for assistance. Because topiramate can be paired with a brief intervention, there is now the exciting possibility of treating most alcohol- dependent individuals in office-based practice or generic treatment settings. Topiramate's additional effects on other impulsedyscontrol disorders make it a particularly interesting compound for the treatment of other comorbid drug or psychiatric disorders. Additionally, future studies should explore whether topiramate can be combined with other putative therapeutic agents to increase its efficacy. One notable clinical challenge in the development of topiramate as a pharmacotherapy to treat alcohol dependence is the determination of the smallest dose that can result in efficacy, thereby achieving the optimum balance between therapeutic benefit and adverse event profile. Animal data do provide support for topiramate's general anti-drinking effects but also indicate that its mechanisms of action might rely on several complex pharmacobehavioral changes. Additional preclinical studies are needed to elucidate more clearly the basic mechanistic processes that underlie topiramate's efficacy as a treatment for alcohol dependence. Preclinical information that topiramate may have differential effects based on genetic vulnerability opens up the possibility of future methods to optimize treatment.

Interictal spikes in developing rats cause long-standing cognitive deficits

Frequent interictal spikes are a common finding in the electroencephalograms of children with epileptic encephalopathies. While it is well recognized that interictal spikes are a biological marker of seizures and can lead to transitory cognitive impairment, whether interictal spikes can result in long-standing adverse effects on learning and memory in children is not known. Here we investigated the consequences of interictal spikes in rat pups without seizures on long-term learning and memory. Rat pups were given a low dose of flurothyl for 4h for 10 days during continuous electroencephalographic monitoring. Rats developed interictal spikes without seizures while age-matched controls under similar testing conditions had few interictal spikes. When rats were tested as adults, there was impairment in reference memory in the probe test of the Morris water maze, reference memory impairment in the four-trial radial-arm water maze and impaired long-term potentiation. Early-life interictal spikes resulted in impaired new cell formation and decreased cell counts in the hippocampus but did not cause an increase in apoptosis. This study, for the first time demonstrates that interictal spikes in rat pups without seizures can result in long-standing spatial cognitive impairment. Our findings suggest that suppressing IIS may be as important as treating seizures during brain development.

Three-week combination treatment with ACTH + magnesium sulfate versus ACTH monotherapy for infantile spasms: a 24-week, randomized, open-label, follow-up study in China

BACKGROUND

Infantile spasms (IS) is an age-specific and severe epileptic encephalopathy that occurs in infancy and early childhood and is usually refractory to conventional antiepileptic drugs. Adrenocorticotropic hormone (ACTH) has been the treatment of choice for IS, but ACTH use has been associated with infection and hypertension. Magnesium ion is an N-methyl-D-aspartic acid (NMDA)-noncompetitive antagonist that might inhibit NMDA activity and has antiepileptic and neuroprotective effects.

OBJECTIVE

This study compared the efficacy and tolerability of ACTH + magnesium sulfate (MgSO(4)) versus ACTH monotherapy for the treatment of IS.

METHODS

This 24-week, randomized, open-label follow-up study enrolled male and female infants with IS. Patients were randomly assigned to receive ACTH 25 U/d + MgSO(4) 0.25 g/kg/d, or ACTH 25 U/d only (control), intravenously for 3 weeks. Efficacy was assessed over a period of 24 weeks based on seizure frequency, EEG, and Gesell testing of psychomotor skills (subscales: language, motor, adaptive, and personal-social skills; measured using a developmental quotient [DQ] ). Tolerability was assessed by monitoring for adverse events using laboratory analysis and clinical evaluation.

RESULTS

Thirty-eight infants were enrolled (23 male, 15 female; median age, 9.2 months; 19 patients per group). At 12 weeks, 14 patients (73.7%) who received ACTH + MgSO(4) and 9 patients (47.4%) in the control group were seizure free. At 24 weeks, seizure-free rates were 12 (63.2%) in the ACTH + MgSO(4) group and 10 (52.6%) in the control group. On EEG, 9 patients (47.4%) in the ACTH + MgSO(4) group achieved complete recovery (normalized EEG), 5 (26.3 %) attained partial improvement (multifocal spike wave), and 5 (26.3%) had no improvement (hypsarrhythmia or modified hypsarrhythmia). At 4 weeks, in the control group, 5 patients (26.3 %) achieved complete recovery, 6 (31.6%) achieved partial improvement, and 8 (42.1%) had no improvement. Of the 12 patients who were seizure free at 24 weeks in the ACTH + MgSO(4) group, 11 (91.7%) had complete recovery (normalized EEG); this rate was 7 of 10 (70.0%) in the control group. In the ACTH + MgSO(4) group, the change from baseline to 24 weeks in mean (SD) personal-social DQ was significant (from 48.6 [6.4] to 65.2 [7.1], respectively; P < 0.05). In the control group, the difference before and after treatment was nonsignificant (47.7 [6.0] vs 49.9 [4.4]). None of the other Gesell test findings were significant versus baseline. The most common AEs included upper respiratory tract infection and pyrexia (both, 3 [15.8%] per group); diarrhea (2 [10.5%] per group); and hypertension, insomnia, and irritability (all, 0 in the ACTH + MgSO(4) group and 2 [10.5%] in the control group). None of the between-group differences in the prevalences of AEs were significant between the 2 groups.

CONCLUSIONS

In this study in infants with IS, the proportions of patients who were seizure free from 4 to 24 weeks were significantly greater in the ACTH + MgSO(4) group compared with the ACTH monotherapy group. Personal-social neurodevelopment was significantly improved from baseline in the group that received combination treatment. Both treatments were generally well tolerated. International Standard Randomized Controlled Trial no. ISRCTN 78654111.

Developing an animal model for infantile spasms: pathogenesis, problems and progress

Infantile spasms (IS), the most common of the early epileptic encephalopathies, afflicts thousands of children each year and results in significant disability. Also known as West syndrome, IS is characterized by intractable stereotyped seizures, poor developmental outcome and a characteristic electroencephalogram (EEG) pattern. IS often progresses into another epileptic encephalopathy known as Lennox-Gastaut syndrome, and continues with the patient being burdened by lifelong epilepsy and varying degrees of mental retardation. Little is known about the biological basis of IS. As the etiologies of IS are diverse, the multiple causes must converge into a final common pathway that results in this specific epilepsy phenotype. Finding a model or models to test this final pathway is necessary both to understand why the greatest susceptibility to seizure development occurs during infancy and early childhood, and what underlies the decreased cognitive potential associated with IS. Furthermore, appropriate models would permit better testing of potential therapies directed specifically at IS. This review will describe the clinical features and etiologies of IS; the ideal features that IS models should contain; and the IS models that exist currently. Finally, we will discuss the limitations of these models and the potential avenues for future research on IS.

Targeted loss of Arx results in a developmental epilepsy mouse model and recapitulates the human phenotype in heterozygous females

Mutations in the X-linked aristaless-related homeobox gene (ARX) have been linked to structural brain anomalies as well as multiple neurocognitive deficits. The generation of Arx-deficient mice revealed several morphological anomalies, resembling those observed in patients and an interneuron migration defect but perinatal lethality precluded analyses of later phenotypes. Interestingly, many of the neurological phenotypes observed in patients with various ARX mutations can be attributed, in part, to interneuron dysfunction. To directly test this possibility, mice carrying a floxed Arx allele were generated and crossed to Dlx5/6(CRE-IRES-GFP)(Dlx5/6(CIG)) mice, conditionally deleting Arx from ganglionic eminence derived neurons including cortical interneurons. We now report that Arx(-/y);Dlx5/6(CIG) (male) mice exhibit a variety of seizure types beginning in early-life, including seizures that behaviourally and electroencephalographically resembles infantile spasms, and show evolution through development. Thus, this represents a new genetic model of a malignant form of paediatric epilepsy, with some characteristics resembling infantile spasms, caused by mutations in a known infantile spasms gene. Unexpectedly, approximately half of the female mice carrying a single mutant Arx allele (Arx(-/+);Dlx5/6(CIG)) also developed seizures. We also found that a subset of human female carriers have seizures and neurocognitive deficits. In summary, we have identified a previously unrecognized patient population with neurological deficits attributed to ARX mutations that are recapitulated in our mouse model. Furthermore, we show that perturbation of interneuron subpopulations is an important mechanism underling the pathogenesis of developmental epilepsy in both hemizygous males and carrier females. Given the frequency of ARX mutations in patients with infantile spasms and related disorders, our data unveil a new model for further understanding the pathogenesis of these disorders.

Vigabatrin in the treatment of childhood epilepsy: a retrospective chart review of efficacy and safety profile

PURPOSE

To review the efficacy, cognitive outcome and safety profile in children treated with vigabatrin (VGB) for infantile spasms (IS) and partial epilepsies related to tuberous sclerosis complex (TSC) and other etiologies.

METHODS

Retrospective review of children followed in the Pediatric Epilepsy Program of Massachusetts General Hospital for Children between May 2001 and March 2006 who were treated with VGB.

RESULTS

Eighty-four children were treated with VGB, 68 of them were treated for IS, and 59 were treated for partial seizures (PS). Etiology (TSC or other) was the only predictive factor for IS control with VGB (p < 0.0003). IS control was achieved in 73% of children with TSC and 27% of children with other etiologies (combined 56%). Partial onset seizures were controlled in 34% of all children, (17% seizure free,17%reduction in seizure frequency >50%) and no predictive factor was found. Shorter time from seizure onset to VGB treatment (p < 0.027) and longer total time on VGB (p < 0.045) was associated with better IQ-developmental quotient (DQ) outcome in children treated for IS, but not with IS control. Adverse events were seen in 13%. Electroretinogram and/or behavioral visual field (VF) testing was done in 52%. VGB was discontinued in one case due to abnormal electroretinogram (ERG) findings.

CONCLUSION

We confirm the efficacy of VGB in the treatment of IS and PS in an American population. VGB may improve cognitive outcome in the absence of complete IS control, but this finding is of uncertain clinical significance. VGB was well tolerated, and ophthalmologic side effects were uncommon.

Time interval from a brain insult to the onset of infantile spasms

The temporal latency between an encephalopathic event and the onset of infantile spasms cannot be determined in the majority of symptomatic cases (e.g. genetic conditions, cerebral malformations). However, we can measure this interval when a previously normal infant sustains brain injury followed by infantile spasms. This information has implications for understanding the underlying pathophysiologic basis for infantile spasms and, also, is germane to allegations that a close temporal relationship between vaccination and the onset of this seizure disorder establishes causation. We identified 19 published cases with sufficient information. The interval between brain injury and the onset of infantile spasms ranged from 6 weeks to 11 months (mean = 5.1 months). A similar temporal latency occurs in children with perinatal cerebral infarction and infantile spasms. We conclude that infantile spasms do not occur acutely following an encephalopathic event. This interval of weeks to months is consistent with prior studies indicating temporal latency between brain injury and the onset of other types of epilepsy, as well as with the previously proposed developmental desynchronization hypothesis. The findings refute claims that a close temporal association between an immunization and the onset of infantile spasms establishes causation.

Recognition and management of pediatric seizures

It is not unusual for the primary care provider to have a child present with unusual paroxysmal events or dermatological lesions that bear further investigation. Although most children with epilepsy are treated and managed by pediatric neurologists, it is imperative that the primary care provider have a clear understanding of associated comorbidities, as well as information on the available anti-epileptic drugs, their side effects, and the need for further monitoring. Those children with epilepsy whose seizures become intractable, failing to be controlled with three or more medications used appropriately at adequate doses, should be referred to a comprehensive epilepsy center for consideration for other treatments. These may include the ketogenic diet, vagal nerve stimulation, or epilepsy surgery.

Role of interictal epileptiform abnormalities in cognitive impairment

The epileptic encephalopathies are conditions in which neurological deterioration is attributable entirely or partly to epileptic activity and is due to very frequent or severe seizures or severely abnormal electroencephalograms (EEGs), or both. Evidence for the concept that seizures or the abnormal EEGs are responsible for the cognitive deterioration is the observation that patients can improve dramatically when therapy eliminates or reduces seizure frequency and improves or normalizes the EEG. For example, children with the syndrome of continuous spike-wave of sleep (CSWS) have electrical status epilepticus during sleep (ESES) and cognitive regression. Although seizures often occur in the disorder, there are indications that the EEG abnormalities are responsible for the cognitive regression. Interictal spikes, which correspond to a large intracellular depolarization with evoked action potentials, in many ways mimic a "miniseizure." Interictal spikes can result in transitory cognitive impairment with the type of deficit dependent on where in the cortex the spike arises. We suggest that interictal spikes, particularly if frequent and widespread, can impair cognitive abilities, through interference with waking learning and memory, and memory consolidation during sleep.

Epilepsy syndromes in infancy

An increasing number of infantile epilepsy syndromes have been recognized. However, a significant number of infants (children aged 1-24 months) do not fit in any of the currently used subcategories. This article reviews the clinical presentation, electroencephalographic findings, evolution, and management of the following entities: early infantile epileptic encephalopathy, early myoclonic epilepsy, infantile spasms/West syndrome, severe myoclonic epilepsy of infancy, myoclonic-astatic epilepsy, generalized epilepsy with febrile seizures plus, malignant migrating partial seizures of infancy, hemiconvulsions-hemiplegia-epilepsy, benign myoclonic epilepsy, and benign familial/nonfamilial infantile seizures. Issues related to their classification are addressed.

Recent advances in the development of treatments for alcohol and cocaine dependence: focus on topiramate and other modulators of GABA or glutamate function

Neuroscientific developments have promulgated interest in developing efficacious medications for the treatment of substance dependence. Previous pharmacological strategies that involve the use of relatively specific medications to alter corticomesolimbic dopaminergic neuronal activity--the critical pathway for expression of the reinforcing effects of abused drugs--have yielded modest efficacy in the treatment of alcohol dependence, and no medication has been established as a treatment for cocaine dependence. Since corticomesolimbic dopaminergic neurons interact with other neurotransmitters that modulate the effects of dopamine in the nucleus accumbens, would it not be possible to control these dopaminergic effects more reliably with a medication that acts contemporaneously on more than one neuromodulator of dopaminergic function? Further, since the long-term use of either alcohol or cocaine results in neuronal adaptations as a result of sensitisation, would the chances of effective therapy not be bolstered by administering a medication that was also able to mitigate these chronic effects? Thus, a new conceptual approach is needed. My proposal is that a medication--in this case topiramate--that principally potentiates inhibitory GABA(A) receptor-mediated input and antagonises excitatory glutamatergic afferents to the corticomesolimbic dopaminergic system should have therapeutic potential in treating either alcohol or cocaine dependence or perhaps both. This is because the principal neurochemical effects of topiramate would not only serve to decrease the acute reinforcing effects of alcohol or cocaine, but might also facilitate cessation of their use following a period of long-term use by decreasing neuronal sensitisation. This overview highlights the scientific concepts and clinical evidence for the development of topiramate in the treatment of alcohol dependence and introduces preliminary evidence to indicate that it might also have utility in treating cocaine dependence. Finally, to place the material on topiramate in context, information has been included on the utility and development of other medications that modulate GABA- or glutamate-mediated neuronal systems for the treatment of alcohol or cocaine dependence.

Progress in the development of topiramate for treating alcohol dependence: from a hypothesis to a proof-of-concept study

Advances in neuroscientific knowledge have evoked interest in developing effective medications for the treatment of alcohol dependence. Pharmacological approaches that involve the use of relatively specific medications at a particular neuronal target to modulate corticomesolimbic dopamine neuronal activity, the critical pathway for expression of the reinforcing effects of abused drugs, have yielded modest efficacy in the treatment of alcohol dependence. A new approach is needed. Because corticomesolimbic dopamine neurons interact with a variety of neurotransmitters that modulate its effects in the nucleus accumbens, it might be possible to more reliably control these dopaminergic effects with a medication that acted contemporaneously on more than one neuromodulator of dopamine function. Additionally, because alcohol use results in neuronal adaptations due to sensitization, the chances of effective therapy might be bolstered by administering a medication that also has utility with mitigating its chronic effects. My proposed conceptual framework suggests that a medication that facilitates inhibitory gamma-aminobutyric acid-A input and antagonizes excitatory glutaminergic afferents to the nucleus accumbens would have pharmacotherapeutic potential in treating the alcohol dependence syndrome because these effects would act contemporaneously to suppress corticomesolimbic dopamine release. Through similar effects, topiramate might also aid chronic drinkers to wean themselves off alcohol and might ameliorate the symptoms of alcohol withdrawal. This commentary highlights the scientific concepts and clinical evidence for the development of topiramate in the treatment of alcohol dependence.

Topiramate-induced neuromodulation of cortico-mesolimbic dopamine function: a new vista for the treatment of comorbid alcohol and nicotine dependence?

Alcohol and nicotine dependence are commonly occurring disorders that together represent the most important preventable causes of morbidity and mortality in the United States. While there have been differences of opinion as to which disorder to treat first when they occur, there is growing evidence that a management strategy addressing both conditions contemporaneously would be optimal. Advances in the neurosciences have demonstrated not only that the reinforcing effects of both alcohol and nicotine are mediated by similar mechanisms resulting in enhanced activity of the cortico-mesolimbic dopamine system, but that their neurochemical interactions can lead to an aggregation of these effects. Despite this striking neurobiological overlap between alcohol and nicotine consumption, few studies have sought to take advantage of this commonality by devising a pharmacological approach that serves to treat both disorders. The results of our proof-of-concept study showed that topiramate is a promising medication for the treatment of both alcohol and nicotine dependence, presumably by its ability to modulate cortico-mesolimbic dopamine function profoundly; however, other mechanisms might also contribute to this effect. Further studies are ongoing to establish and extend topiramate's efficacy in the treatment of each and both disorders.