Infantile spasms

Evolution of Surgical Management for Intractable Epileptic Spasms

The understanding and management of epileptic spasms has considerably evolved since the mid 19th century. The realization that epileptic spasms can be generated from a focal brain lesion played a pivotal role in the development of neurosurgical management for intractable forms of this epilepsy. During pre-surgical planning, the addition of functional FDG PET imaging has further refined the electroencephalographic localization of epileptogenic lesions. In some cases, neurosurgical resection of a focus that is co-localized by the FDG PET scan and electroencephalography can lead to partial or complete reversal of developmental delay along with reduced seizure frequency or seizure freedom. In cases where near-complete hemispheric cortex is implicated in spasm generation, subtotal hemispherectomy has shown encouraging results. Moreover, palliative resection of the major perpetrating focus in carefully chosen patients with bilateral multifocal spasms has also led to favorable outcomes. However, in patients with tuberous sclerosis with high tuber burden, the localizing value of FDG PET imaging may be limited. In such cases, employment of AMT PET technology has become a valuable tool for localization of actively epileptogenic tubers. This article highlights the historic steps in the successful advancements of neurosurgical interventions for the treatment of intractable epileptic spasms.

Compound Heterozygous PIGS Variants Associated With Infantile Spasm, Global Developmental Delay, Hearing Loss, Visual Impairment, and Hypotonia

Glycosylphosphatidylinositol (GPI) is a membrane anchor for cell surface proteins. Inherited GPI deficiencies are a new subclass of congenital disorders of glycosylation. Phosphatidylinositol glycan class S (PIGS) is a subunit of the GPI transamidase which plays important roles in many biological processes. In this study, we present a Chinese boy with infantile spasms (ISs), severe global developmental delay, hearing loss, visual impairment (cortical blindness), hypotonia, and intellectual disability and whose whole-exome sequencing (WES) identified compound heterozygous variants in PIGS (MIM:610271):c.148C > T (p.Gln50^∗) and c.1141_1164dupGACATGGTGCGAGTGATGGAGGTG (p.Asp381_Val388dup). Flow cytometry analyses demonstrated that the boy with PIGS variants had a decreased expression of GPI-APs. This study stresses the importance of including the screening of PIGS gene in the case of pediatric neurological syndromes and reviews the clinical features of PIGS-associated disorders.

Effects of Adrenocorticotropic Hormone Treatment on Heart Muscle in Patients with Infantile Spasm

Background and aim

Infantile spasm (IS) is a common epileptic syndrome of childhood epilepsies. The most effective treatment for IS is adrenocorticotropic hormone (ACTH). We hypothesized that ACTH treatment might change myocardial systolic and diastolic performance and cause cardiovascular side effects. This study aims to evaluate the effects of ACTH treatment on the heart muscle in IS patients.

Materials and methods

Eighteen newly diagnosed patients with IS participated in the study. ACTH (Synacthen® Depot) administered for two months in a total of 18 doses. A twelve-channel-surface electrocardiogram (ECG) and echocardiography performed in all patients before ACTH treatment, the second month after ACTH treatment (end of treatment), and two months later (after treatment). The systolic and diastolic myocardial functions were assessed by conventional and tissue Doppler imaging (TDI).

Results

The mean age of the patients was 8.1 months, and the patient group consisted of five female and 13 male subjects. None of the patients had clinically significant arrhythmia during treatment. After treatment, the mean heart rates of the patients significantly decreased (p=0.02), the systolic and diastolic blood pressures of patients did not change. We observed mild septal hypertrophy and an increase in the left ventricle mass index with ACTH treatment. Septal hypertrophy did not show progression until the fourth month after treatment. After ACTH treatment, patients had higher left ventricular myocardial performance index and lower E′ and A′ values at the mitral lateral annuli, however, these values didn't statistically significant from pretreatment values.

Conclusion

The low dose and short duration ACTH treatment in IS patients may cause subclinical myocardial hypertrophy. ACTH treatment has no significant side effects on cardiac functions.

Non-invasive, multimodal analysis of cortical activity, blood volume and neurovascular coupling in infantile spasms using EEG-fNIRS monitoring

Although infantile spasms can be caused by a variety of etiologies, the clinical features are stereotypical. The neuronal and vascular mechanisms that contribute to the emergence of infantile spasms are not well understood. We performed a multimodal study by simultaneously recording electroencephalogram and functional Near-infrared spectroscopy in an intentionally heterogeneous population of six children with spasms in clusters. Regardless of the etiology, spasms were accompanied by two phases of hemodynamic changes; an initial change in the cerebral blood volume (simultaneously with each spasm) followed by a neurovascular coupling in all children except for the one with a large porencephalic cyst. Changes in cerebral blood volume, like the neurovascular coupling, occurred over frontal areas in all patients regardless of any brain damage suggesting a diffuse hemodynamic cortical response. The simultaneous motor activation and changes in cerebral blood volume might result from the involvement of the brainstem. The inconstant neurovascular coupling phase suggests a diffuse activation of the brain likely resulting too from the brainstem involvement that might trigger diffuse changes in cortical excitability.

Atonic elements combined or uncombined with epileptic spasms in infantile spasms

OBJECTIVE

To study the atonic elements combined or uncombined with epileptic spasms in infantile spasms.

METHODS

The demographic data, clinical characteristics, electroencephalogram (EEG), and polyelectromyography (PEMG) features were analyzed in 12 infantile spasm patients with atonic elements.

RESULTS

A total of 29 EEGs were recorded. Hypsarrhythmia or hypsarrhythmia variants were identified during interictal EEG. Insular or clustered epileptic spasms occurred in all. Three subtypes of atonic elements combined or uncombined with epileptic spasms (spasm-atonic, pure atonic, and atonic-spasm seizures) were observed electroclinically, which could present insularly or in cluster or altered with epileptic spasms in the same cluster. The ictal EEG showed generalized high-amplitude slow waves presenting alone or combined with other patterns. The corresponding PEMG showed an obvious electrical silence alone or preceding or following a crescendo-decrescendo pattern generated from myoelectric burst.

CONCLUSIONS

Atonic elements combined or uncombined with epileptic spasms was a newly noticed phenomenon in infantile spasms, which was artificially divided into three subtypes here. It might be a variant of epileptic spasms or a unique seizure type.

SIGNIFICANCE

Atonic elements combined or uncombined with epileptic spasms was a previously ignored phenomenon in infantile spasms, which should be seriously considered in clinical practice.

Unilobar surgery for symptomatic epileptic spasms

Objective

To assess factors associated with favorable seizure outcome after surgery for symptomatic epileptic spasms and improve knowledge on pathophysiology of this seizure type.

Methods

Inclusion criteria were: (1) age between 6 months and 15 years at surgery; (2) active epileptic spasms; (3) follow‐up after surgery >1 year.

Results

We retrospectively studied 80 children (aged 1.3 ± 2 years at seizure onset; 5.8 ± 4 years at surgery, 11.7 ± 5.7 years at last follow up). Magnetic resonance imaging (MRI) revealed structural abnormalities in 77/80 patients (96.3%; unilateral in 69: 89.6%). We performed invasive recordings in 24 patients (30%). In 21 patients in whom MRI or histopathology detected a lesion, electrodes exploring it constantly captured initial ictal activity at spasm onset. Fifty‐eight patients (72.5%) underwent unilobar and 22 (27.5%) multilobar or hemispheric procedures. At last follow‐up, 49 patients (61.3%) were in Engel class I. Multivariate logistic models showed completeness of resection of the seizure onset zone (OR = 0.016, 95%CI: 0.002, 0.122) and of the MRI visible lesion (OR = 0.179, 95% CI: 0.032, 0.999) to be significantly associated with Engel class IA outcome. Unfavorable outcome was associated with an older age at surgery, when it reflected a longer duration of epilepsy (OR = 1.383, 95% CI: 0.994,1.926).

Interpretation

Data emerging from invasive recordings and the good seizure outcome following removal of discrete epileptogenic lesions support a focal cortical origin of spasms. In patients with discrete epileptogenic lesions, the pragmatic approach to surgery should follow the same principles applied to focal epilepsy favoring, whenever possible, unilobar, one‐stage resections.

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.

Neuronal networks in west syndrome as revealed by source analysis and renormalized partial directed coherence

West syndrome is a severe epileptic encephalopathy of infancy with a poor developmental outcome. This syndrome is associated with the pathognomonic EEG feature of hypsarrhythmia. The aim of the study was to describe neuronal networks underlying hypsarrhythmia using the source analysis method (dynamic imaging of coherent sources or DICS) which represents an inverse solution algorithm in the frequency domain. In order to investigate the interaction within the detected network, a renormalized partial directed coherence (RPDC) method was also applied as a measure of the directionality of information flow between the source signals. Both DICS and RPDC were performed for EEG delta activity (1-4 Hz) in eight patients with West syndrome and in eight patients with partial epilepsies (control group). The brain area with the strongest power in the given frequency range was defined as the reference region. The coherence between this reference region and the entire brain was computed using DICS. After that, the RPDC was applied to the source signals estimated by DICS. The results of electrical source imaging were compared to results of a previous EEG-fMRI study which had been carried out using the same cohort of patients. As revealed by DICS, delta activity in hypsarrhythmia was associated with coherent sources in the occipital cortex (main source) as well as the parietal cortex, putamen, caudate nucleus and brainstem. In patients with partial epilepsies, delta activity could be attributed to sources in the occipital, parietal and sensory-motor cortex. In West syndrome, RPDC showed the strongest and most significant direction of ascending information flow from the brainstem towards the putamen and cerebral cortex. The neuronal network underlying hypsarrhythmia in this study resembles the network which was described in previous EEG-fMRI and PET studies with involvement of the brainstem, putamen and cortical regions in the generation of hypsarrhythmia. The RPDC suggests that brainstem could have a key role in the pathogenesis of West syndrome. This study supports the theory that hypsarrhythmia results from ascending brainstem pathways that project widely to basal ganglia and cerebral cortex.

Outcomes of epileptic spasms in patients aged less than 3 years: single-center United States experience

Retrospective review was performed of children aged <3 years with epileptic spasms at our center from 2004-2010. Short-term (<6 months) and long-term (≥6 months) outcomes were assessed. We included 173 children (104 boys; median age of onset, 6.8 months) with epileptic spasms of known (62%) and unknown (38%) etiology. Treatments included adrenocorticotropic hormone (n = 103), vigabatrin (n = 82), phenobarbital (n = 34), and other agents (n = 121). Short-term treatment with adrenocorticotropic hormone and vigabatrin provided better epileptic spasm control in groups with known and unknown etiology than other agents. At follow-up (6-27 months), 54% of children manifested seizures, and 83% manifested developmental delay. Known etiology was a predictor of poor developmental outcome (P = 0.006), whereas bilateral/diffuse brain lesions predicted both poor development and seizures (P = 0.001 and 0.005, respectively). Initial presentations of epileptic spasms with hypotonia or developmental delay most strongly predicted both seizures and neurodevelopmental outcomes (P < 0.001). In a child presenting with epileptic spasms with developmental delay or hypotonia, no specific treatment may offer superior benefit.

Two female siblings with West syndrome: Familial idiopathic West syndrome with genetic susceptibility and variable phenotypic expression

The West syndrome (WS) is a characteristic form of epilepsy which usually begins in the first year of life. We describe two female siblings, aged 4 and 2 years, respectively, born from third degree consanguineous parents, with infantile spasms and developmental delay. Epileptic spasms had not a good outcome under antiepileptic drug treatment. Clinical and imaging features were of different severity in both siblings. Routine biochemical tests, metabolic investigations, and chromosomal analysis were normal. We analyzed CDKL5 gene by direct sequences and denaturing high-performance liquid chromatography using Transgenomic WAVE system. Analysis of the CDKL5 gene, which is responsible for female patient with WS, did not show any disease-causing mutation. WS has heterogeneous backgrounds, and may be more than one gene is responsible for its familial forms. In this family, consanguinity is observed in parents, which usually suggests that autosomal recessive inheritance is likely.

Statistical mapping of ictal high-frequency oscillations in epileptic spasms

PURPOSE

We assessed 636 epileptic spasms seen in 11 children (median 44 spasms per child) and determined the spatial and temporal characteristics of ictal high-frequency oscillations (HFOs) in relation to the onset of spasms.

METHODS

Electrocorticography (ECoG) signals were sampled from 104-148 cortical sites per child, and the dynamic changes of ictal HFOs were animated on each individual's three-dimensional (3D) magnetic resonance (MR) image surface.

KEY FINDINGS

Visual assessment of ictal ECoG recordings revealed that each spasm event was characterized by augmentation of HFOs. Time-frequency analysis demonstrated that ictal augmentation of HFOs at 80-200 Hz was most prominent and generally preceded those at 210-300 Hz and at 70 Hz and slower. Recruitment of HFOs in the rolandic cortex preceded the clinical onset objectively visualized as electromyographic deflection. The presence or absence of ictal motor symptoms was related more to the amplitude of HFOs in the Rolandic cortex than in the seizure-onset zone. In a substantial proportion of epileptic spasms, seizure termination began at the seizure-onset zone and propagated to the surrounding areas; we referred to this observation as the "ictal doughnut phenomenon." Univariate analysis suggested that complete resection of the sites showing the earliest augmentation of ictal HFOs was associated with a good surgical outcome.

SIGNIFICANCE

Recruitment of HFOs at 80-200 Hz in the rolandic area may play a role in determining seizure semiology in epileptic spasms. Our study using macroelectrodes demonstrated that ictal HFOs at 80-200 Hz preceded those at 210-300 Hz.

Physicochemical characterization of solid dispersions of three antiepileptic drugs prepared by solvent evaporation method

We have investigated the solid dispersion and dissolution profiles of three antiepileptic drugs (carbamazepine (CBZ), oxcarbazepine (OXC) and rufinamide (RFN)) with different aqueous solubilities, prepared by the solvent evaporation method. Solid dispersions of the three drugs in hydroxy-propylmethylcellulose (HPMC), with drug:polymer ratios of 1:4, were prepared and characterized by differential scanning calorimetry (DSC), Fourier transformation infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy. The release mechanism was also investigated and the kinetic order of the solid dispersions was evaluated. It appeared that the dissolution behaviour depended on the physicochemical properties of the drug and drug-polymer interactions. DSC thermographs showed amorphous forms for all drugs confirmed by XRD patterns. The FTIR spectra of CBZ and OXC demonstrated drug interactions with HPMC through hydrogen polymer bonds. Thus, solid dispersions of these drugs had an improved dissolution profile. In contrast, solid dispersions of RUF showed modest enhancement of dissolution, suggesting negligible drug-polymer interactions. The different dissolution behaviour is attributed to the extent of interactions between the polymer hydroxyl group and the drug amide groups.

Long-term outcome of symptomatic infantile spasms established by video-electroencephalography (EEG) monitoring

In this study, we examine the long-term clinical outcome of children with symptomatic infantile spasm. The children between 2 and 18 years of age diagnosed with symptomatic infantile spasms were reviewed. Sixty-eight children (age range, 2-13 years; mean, 4.5 years) met the inclusion criteria. Children who underwent epilepsy surgery were excluded. Age of onset for infantile spasms ranged from 1 to 24 months (mean, 7.1 months). Developmental delay was noted in all; there was seizure freedom in 14 children (20.5%). Infantile spasms were reported as the only seizure type in 10 (14.5%) children older than age 2 years. During the follow-up; symptomatic generalized epilepsy was diagnosed in 23 children (34%) and focal epilepsy in 21 (31%). The long-term outcome of these children remains unchanged in the majority of the children with symptomatic infantile spasms. We could not establish any risk factor that might be related to favorable or adverse outcome.

Patients with West syndrome whose ictal SPECT showed focal cortical hyperperfusion

To clarify the mechanism of clustered spasms in West syndrome (WS), we examined ictal SPECT and EEG, as well as those during the interictal period, in three patients with symptomatic WS who had apparent focal cerebral lesions. For ictal SPECT and EEG, we monitored the patients with EEG, and as soon as we noticed the occurrence of clustered spasms clinically and electroencephalographically, [(99m)Tc]ECD was injected intravenously and flushed thoroughly with saline. In these three patients, regional cerebral blood flow (rCBF) increased during ictus and decreased during the interictal period in the area that coincided with the focal cerebral lesion recognized by CT/MRI. The ictal hyperperfusion of bilateral basal ganglia was also detected in two of the three patients. The ictal EEG showed a diffuse slow wave complex corresponding to a clinical spasm. The sharp waves that preceded the diffuse slow wave complex and the spasm appeared in the same area in which rCBF increased during ictus. None of the patients showed partial seizure before or after clustered spasms clinically or electroencephalographically during the ictal SPECT study. Secondary generalization from a cerebral focus may explain the mechanism of spasms in these patients with WS: focal cortical discharge may primarily generate clustered spasms and trigger the brainstem and basal ganglia structures to produce spasms.

Maternal IgG suppresses NMDA-induced spasms in infant rats and inhibits NMDA-mediated neurotoxicity in hippocampal neurons

Maternal immunoglobulin G (IgG) was derived from Wistar rats that just delivered the new offsprings. We examined the effect of this maternal IgG on infantile spasms induced by N-methyl-d-aspartate (NMDA) in immature rats. Pup animals were treated subcutaneously with 10 mg/kg/day maternal IgG from day 11 to day 15 after birth followed by a single intraperitoneal dose of NMDA (15 mg/kg). Administration of maternal IgG decreased the severity and increased the number of ACTH immunoreactive cells in the cortex of rats with NMDA-induced spasms. Furthermore, maternal IgG inhibited NMDA-induced intracellular LDH activity in cultured hippocampal neurons in a dose-dependent manner. The results indicate that maternal IgG can attenuate NMDA-induced seizures. In infantile spasms, some factors may during pregnancy negatively affect the transfer of maternal IgG from mother to fetus thereby causing a decrease in the amount of protective maternal IgG.

A comparison of seizure outcome after callosotomy in patients with Lennox-Gastaut syndrome and a positive or negative history for West syndrome

PURPOSE

This retrospective study was designed to clarify the role of West syndrome in post-callosotomy seizure outcome in patients with Lennox-Gastaut syndrome.

METHODS

From September 1989 to May 1999, 74 patients diagnosed with Lennox-Gastaut syndrome received anterior corpus callosotomy at Taipei Veterans General Hospital, Taiwan. All patients were followed for more than 4 years after surgery. Among them, 21 (28.4%) patients had a history of West syndrome (Group A) whereas 53 (71.6%) patients did not have a history of West syndrome (Group B). Postoperative seizure outcome was compared for these two patient groups.

RESULTS

A total of 16 (76.2%) patients in Group A (positive history) and 29 (54.7%) patients in group B (negative history) achieved significant improvement in seizures after surgery (e.g., seizure reduction of more than 50%). There was no statistical significance (p=0.088) in the difference in outcome between the two groups.

CONCLUSIONS

A history of West syndrome does not appear to influence post-callosotomy seizure outcome in patients with Lennox-Gastaut syndrome.

Cryptogenic Late-onset Epileptic Spasms: An Overlooked Syndrome of Early Childhood?

PURPOSE

Few reports detailing late-onset epileptic spasms have been published. To determine whether this condition merely represents a late variant of classic West syndrome or exhibits specific features distinct from the latter and related to a later stage of brain maturation, we analyzed the whole population with this specific seizure type, excluding symptomatic cases to avoid the effect of brain lesion.

METHODS

We reviewed the files of the 56 children evaluated for epileptic spasms in clusters having begun at age 12 months or later and analyzed clinical and video-EEG data of the 22 patients (4-17 years; mean, 8.5 years) without obvious cause.

RESULTS

Interictal EEG did not show classic hypsarrhythmia. A temporal or temporofrontal slow wave and/or spike focus could be identified in all cases. Twelve children showed spasms with a tonic component. Ictal EEG revealed generalized high-voltage slow wave followed by diffuse voltage attenuation with superimposed fast activity. All children also exhibited other types of recorded seizures consisting of bursts of spike-waves with temporofrontal predominance, reminiscent of "atypical absences." In contrast with the occurrence of tonic components within a cluster of spasms, no tonic seizure stricto sensu was recorded or reported by the caregivers. In 10 children, treatment (two vigabatrin, seven hydrocortisone, one adrenocorticotropic hormone) achieved complete cessation of seizures and disappearance of focal EEG anomalies, but spasms persisted in 12 children.

CONCLUSIONS

The cryptogenic group in our series without recognized cause and temporal or temporofrontal EEG anomalies seems to represent a type of epileptic encephalopathy intermediary between West and Lennox-Gastaut syndromes, in terms of seizure types and interictal EEG, and could correspond to dysfunction of the maturation process of the temporal lobe, possibly due to an undisclosed lesion.

ACTH therapy for Taiwanese children with West syndrome -- efficacy and impact on long-term prognosis

To study the efficacy of adrenocorticotrophic hormone (ACTH) in treating Taiwanese children with West syndrome (WS) and the impact on long-term prognosis, 66 patients with WS (54 symptomatic and 12 cryptogenic) were collected from 1987 to 1998 in a medical center in Taiwan. A total of 53 patients were enrolled in this study and treated with ACTH at the dosage of 2.5IU/kg daily for 2 weeks with gradual tapering in subsequent 6 weeks. Immediate responses, side effects of ACTH and long-term outcomes of the patients including seizure and developmental status were evaluated during the average follow-up period of 35.6 months. The spasm-free percentage after one or two courses of ACTH treatment was 77.4%. Nine (17%) patients encountered severe side effects such as major infections, which prompted us to stop ACTH. At the end of follow-up, 22 (41.5%) patients had intractable seizures but 25 (47.2%) patients remained seizure free with or without anticonvulsants. The ACTH-responders had a better chance of remaining seizure free (P<0.05). Regarding the long-term developmental outcome, 12 (22.6%) patients had normal or borderline development; two thirds of them belonged to the crytpogenic group. Six (11.3%) patients expired and 24 (45.3%) were severely retarded; all but one of them belonged to the symptomatic group. The prognosis of WS heavily relies on whether a patient is cryptogenic or symptomatic (P<0.001). Good response to therapy or short treatment lag did not favorably affect the developmental outcomes of the symptomatic cases. We conclude that the long-term outcomes of WS in Taiwan were generally poor despite of treatment. Only cryptogenic patients had favorable prognosis. For symptomatic patients, ACTH therapy may be used to control the spasms and decrease the incidence of subsequent epilepsy, but it will not improve developmental outcome. Considering a high percentage of severe side effects in our study, a lower dosage of ACTH with adequate therapeutic efficacy but less side effects should be considered for treating Taiwanese children with WS.

Use of ACTH and prednisolone in infantile spasms: Experience from a developing country

BACKGROUND

Adrenocorticotrophic hormone (ACTH) and prednisone are both used to treat infantile spasms (IS) in West syndrome. In many countries, ACTH is expensive and difficult to obtain whereas, prednisone or prednisolone are cheap, given orally and easily available.

AIMS

The purpose of this retrospective data analysis was to compare the efficacy and cost of ACTH and prednisolone in the treatment of IS from the perspective of a developing country.

METHODS

Patients admitted with West syndrome in Children's Hospital, Islamabad, between January 1995 and December 2001 were included in the analysis. The diagnosis was made after eliciting a history of characteristic seizures and detecting hypsarrhythmia on the EEG. Parents were offered the use of either ACTH administered by intramuscular injection or prednisolone given orally. ACTH was expensive and difficult to obtain whereas prednisolone was cheap and easily available.

RESULTS

One hundred and five children were included in the study. Sixty-three were boys and their age ranged from 2 months to 3 years with a mean of 11 months. Thirty-three children received ACTH injections; 27 showed improvement and 11 remained spasms free after discontinuation of injections. Seventy-two patients were given oral prednisolone, 51 responded and 17 remained spasms free after oral steroids were stopped. Overall outcome was similar in both groups. The cost of ACTH injection was more than 100 times the cost of oral prednisolone.

CONCLUSION

No significant difference was seen in the final outcome in both treatment groups. Since prednisolone is inexpensive, easily available and given orally, it is the preferred mode of therapy.

Pathogenesis of infantile spasms: a model based on developmental desynchronization

Infantile spasms is a severe epileptic encephalopathy of infancy. The fundamental cause is unknown, although a number of predisposing conditions are recognized. In this article, the authors critically review current knowledge concerning the pathophysiologic basis of infantile spasms and propose a new model based on developmental desynchronization. It is suggested that infantile spasms may result from a particular temporal desynchronization of two or more central nervous system developmental processes, resulting in a specific disturbance of brain function. The disturbance of function is postulated to be crucially dependent on an unbalanced maturational pattern, in which certain brain systems become dysfunctional owing to divergent developmental status. An important aspect of this model is the idea that disturbed function of a specific kind can result from multiple causative factors, and so can be associated with a variety of different anatomic and/or biochemical abnormalities. Thus, this concept is compatible with the observed diversity of pathologic findings and multiplicity of etiological associations observed in infantile spasms patients.

PET in pediatric diseases

FDG-PET is being increasingly applied to pediatric conditions, particularly in oncology. PET and PET/CT scanning in children are not currently supported by Centers for Medicare and Medicaid Services unless the disease condition coincides with a reimbursed adult condition. The recent merger of the Children's Cancer Group and the Pediatric Oncology Group to form the Children's Oncology Group creates an opportunity to examine the use of FDG-PET in the management of childhood tumors in multi-institutional, cooperative efforts. The interest in incorporating PET imaging technology in pediatric medicine has been evidenced by several recent review articles summarizing the ongoing progress in this area. Future data will show that FDG-PET provides useful diagnostic information and can play a pivotal role in the clinical management and care of children with disease.

Long-term cognitive outcomes of a cohort of children with cryptogenic infantile spasms treated with high-dose adrenocorticotropic hormone

PURPOSE

To evaluate the outcome of children with cryptogenic infantile spasms treated with high-dose synthetic adrenocorticotropic hormone (ACTH) and the relation between early treatment, within 1 month of onset, and outcome.

METHODS

We assessed the long-term cognitive and seizure outcomes of 37 patients with cryptogenic infantile spasms (onset, age 3 to 9 months) receiving standardized treatment regimen of high-dose tetracosactide depot, 1 mg IM every 48 h for 2 weeks, with a subsequent 8- to 10-week slow taper and followed by oral prednisone, 10 mg/day for a month, with a subsequent slow taper for 5 months or until the infant reached the age of 1 year, whichever came later. Development was assessed before treatment. Seizure outcomes were followed up prospectively. Cognitive outcomes were determined after 6 to 21 years and analyzed in relation to treatment lag and pretreatment regression.

RESULTS

Twenty-two infants were treated within 1 month of onset of infantile spasms, and 15 after 1 to 6.5 months. Normal cognitive outcome was found in all 22 (100%) patients of the early-treatment group, and in 40% of the late-treatment group. Normal cognitive outcome was found in all 25 (100%) patients who had no or only mild mental deterioration at presentation, including four in the late-treatment group but in only three of the 12 patients who had had marked or severe deterioration before treatment.

CONCLUSIONS

Early treatment of cryptogenic infantile spasms with a high-dose ACTH protocol is associated with favorable long-term cognitive outcomes. Once major developmental regression lasts for a month or more, the prognosis for normal cognitive outcome is poor. Further studies are needed on the optimal treatment regimen for this disorder.

Infantile spasms versus myoclonus: is there a connection?

Infantile spasms (IS) is usually classified as a form of "myoclonic epilepsy," but the nosology of this whole group of disorders is unclear. Evidence suggests that the spasms are subcortically mediated, but can be modified by input from the cortex, which is believed to be abnormally excitable and disorganized. The latter features may give rise to hypsarrhythmia. The whole issue of myoclonus rests on the phenotype of IS and precise measurements of the length of electromyographic (EMG) bursts. Based on scant EMG data, it would appear that the bursts during flexor spasms are too long for epileptic myoclonus. The nature of tonic spasms of even longer duration is not myoclonic. However, the infrequent spontaneous myoclonic jerks, which can occur without spasms, and head nodding could represent positive and negative myoclonus, respectively. Data can be collected easily through techniques such as back-averaging to resolve the issue of classification and localization of motor phenomena.

The epidemiology of the epilepsies in children

The epilepsies are a heterogeneous collection of neurological conditions and syndromes characterized by recurrent, unprovoked, paroxysmal seizure activity. There are several types of epileptic seizures and syndromes that are unique to children, including infantile spasms, Lennox-Gastaut syndrome and absence seizures. Febrile seizures and neonatal seizures, while not epilepsy, are relatively common types of seizures in infants and children and are likely markers of risk of later epilepsy. Thus, it is important to consider the epidemiological features of the epilepsies as they occur specifically in infants and children. The purpose of this review is to summarize what is currently known about the epidemiology of the childhood epilepsies and to identify promising areas for further population-based studies. The epilepsies are an important cause of neurological morbidity in children. The average annual rate of new cases (incidence) of epilepsy is approximately 5-7 cases per 10,000 children from birth to age 15 years, and in any given year, about 5 of every 1,000 children will have epilepsy. There is evidence that the incidence of the epilepsies in some populations of children may be decreasing over time, and this possibility merits further investigation. Factors that are known to increase risk of the epilepsies in children include congenital malformations of the central nervous system (CNS), moderate or severe head trauma, CNS infections, certain inherited metabolic conditions, and genetic factors. However, these account for only 25% to 45% of cases, and thus, the etiology of most cases of the epilepsies remains obscure. The paucity of well-controlled etiological studies is due largely to formidable methodological problems in conducting epidemiological studies of the epilepsies. The prognosis for seizure control is generally good, although children with remote symptomatic seizures and those with additional neurological disabilities do less well.

Prolactin levels in cerebrospinal fluid of patients with infantile spasms

Infantile spasms are an age-related epileptic syndrome of infancy and are characterized by the combination of clusters of epileptic spasms and specific electroencephalographic findings. The etiology and the pathogenesis of the disease is still unclear. Prolactin has been thought to be specifically related to epileptic seizures. To investigate the possible mechanism of prolactin secretion in infantile spasms cerebrospinal fluid prolactin levels were examined. Fifteen patients with infantile spasms (10 females and five males), 3-16 months of age, were evaluated and compared with age- and sex-matched control subject. Cerebrospinal fluid samples for prolactin were obtained before and after treatment. The mean prolactin levels in the cerebrospinal fluid of the patients before therapy (3.25 +/- 1.48 ng/mL) was higher than the control group (2.38 +/- 0.89 ng/mL), and the difference between the two groups was statistically significant (P < 0.001). The mean prolactin level in the cerebrospinal fluid of the patients after therapy (4.69 +/- 1.47 ng/mL) was demonstrated to be higher than the mean prolactin level before therapy (3.25 +/- 1.48 ng/mL) and the difference between the two groups was statistically significant (P = 0.037). Elevation of cerebrospinal fluid prolactin levels before and after treatment in patients with infantile spasms provided evidence that the cerebrospinal fluid prolactin level is related with neuronal injury.

Medical treatment of patients with infantile spasms

Infantile spasms are the main feature in West syndrome, an age-related epilepsy syndrome that affects 1 in every 2,000-4,000 infants. The authors provide a comprehensive review of the literature about infantile spasms and their therapy. In the United States, the drug of choice for infantile spasms, at least the cryptogenic cases, has been adrenocorticotropic hormone (ACTH). It is generally considered to be more effective than corticosteroids. Adrenocorticotropic hormone appears to alter long-term prognosis of cryptogenic infantile spasms, and helps in some cases of symptomatic infantile spasm. Vigabatrin has been considered the drug of choice for infantile spasms secondary to tuberous sclerosis, and possibly, according to many neurologists, for all cases of infantile spasm. Recent concerns regarding retinopathy associated with vigabatrin therapy are, however, limiting the use of this drug. Valproic acid benefits 40%-70% of patients who failed a trial of ACTH. Nitrazepam is as effective as ACTH in acutely controlling infantile spasms; however, its long-term effects on prognosis have not been studied. Pyridoxine, lamotrigine, topiramate, zonisamide, ketogenic diet, immunoglobulin therapy, felbamate, and thyrotropin-releasing hormone have all been used for the treatment of infantile spasms, but are usually reserved for cases refractory to vigabatrin and/or ACTH.

West syndrome and other infantile epileptic encephalopathies--Indian hospital experience

Children with infantile epileptic encephalopathies comprising 3.5% of the Pediatric Neurology Clinic registrations in a tertiary care hospital were retrospectively analyzed. Data were retrieved from case records and analyzed for seizure semiology, prenatal and perinatal insults, developmental status and relevant investigations. The various therapeutic modalities and their influence on spasm frequency, long-term development and final seizure status were compared. The two primary outcome variables analyzed included final seizure status and developmental outcome. Of the 94 infantile epileptic encephalopathies, West syndrome was the commonest (55.3%), of which two thirds were symptomatic. Etiological factors were prenatal in 66.6% and perinatal in 33.3%. The initial response to ACTH was good in 54.5% with subsequent relapse in 27.8% and for prednisolone was 52.9 and 44.4%, respectively, compared to 25.3% spasms control with conventional antiepileptic drugs. Disease category of infantile epileptic encephalopathies evolved in 4, i.e. early myoclonic encephalopathy to West syndrome 1, early infantile epileptic encephalopathy to West syndrome 1, West syndrome to Lennox-Gastaut syndrome 2. Psychomotor retardation was seen in 88.2%, with 16.1% having normal development at onset of spasms. Microcephaly was associated with delayed development but did not influence final seizure outcome. Final seizure outcome was poor in children with delayed development at onset (adjusted odds ratio [OR] = 4), delay in diagnosis >12 months (OR = 2.27) and in children with Lennox-Gastaut syndrome (OR = 4.75). ACTH/prednisolone and antiepileptic treatment versus antiepileptics alone showed a good final seizure response in 36.6% versus 20%. Development on follow up was delayed in children with initial psychomotor retardation (OR = 23.4) and abnormal electroencephalogram (OR = 7.46). Perinatal factors constituted one third of symptomatic West syndrome. The use of ACTH/corticosteroids resulted in good initial spasm control though final seizure outcome and development were unaffected. Prednisolone had similar response to ACTH in spasm control but higher subsequent relapse rate. Vigabatrin was useful though often unaffordable. The identification of a neurometabolic etiology, though uncommon, has significant therapy implications. Delay in diagnosis was common and negatively influenced final seizure outcome.

Epidemiologic features of infantile spasms in Slovenia

PURPOSE

To determine the epidemiologic features of infantile spasms (ISs) in Slovenia.

METHODS

Medical records of all children with ISs in Slovenia in the period from 1985 to 1995, based on community pediatrician referrals to four hospitals, including all pediatric EEG laboratories, were retrospectively studied. The outcome was assessed by a follow-up study in 1998.

RESULTS

Forty-seven children with ISs were identified over an 11-year interval. The cumulative incidence was 2.06 per 10,000 live births. Among 29 (61.7%) children with symptomatic etiology, 14 cases had prenatal etiology [tuberous sclerosis (TS), seven; vascular insult, three; cerebral malformations, three; Down syndrome, one child], 14 perinatal and one postnatal cause: anoxic brain damage after cardiac surgery. Cryptogenic and idiopathic etiology were diagnosed in 13 (27.6%) and five (10.6%) of 47 cases, respectively. The age of onset of ISs ranged from 2 to 10 months. As initial treatment, steroids were used in 19 children (remission in 10); vigabatrin in seven (remission in four), and other antiepileptic drugs (AEDs) in 20 children (remission in six). According to the follow-up study, 18 (38.3%) children were seizure free, and 14 of them had normal mental development. Among 29 mentally retarded children (14 severely), 26 belonged to the symptomatic group. Four children died.

CONCLUSIONS

The incidence of ISs in Slovenia is similar to that in some parts of the United States, but lower than that in Finland or Sweden. The outcome depends mainly on etiology. Additional neuroimaging studies are needed for evaluation of cryptogenic cases.

ACTH treatment of infantile spasms: mechanisms of its effects in modulation of neuronal excitability

The efficacy of ACTH, particularly in high doses, for rapid and complete elimination of infantile spasms (IS) has been demonstrated in prospective controlled studies. However, the mechanisms for this efficacy remain unknown. ACTH promotes the release of adrenal steroids (glucocorticoids), and most ACTH effects on the central nervous system have been attributed to activation of glucocorticoid receptors. The manner in which activation of these receptors improves IS and the basis for the enhanced therapeutic effects of ACTH--compared with steroids--for this disorder are the focus of this chapter. First, a possible "common excitatory pathway," which is consistent with the many etiologies of IS and explains the confinement of this disorder to infancy, is proposed. This notion is based on the fact that all of the entities provoking IS activate the native "stress system" of the brain. This involves increased synthesis and release of the stress-activated neuropeptide, corticotropin-releasing hormone (CRH), in limbic, seizure-prone brain regions. CRH causes severe seizures in developing experimental animals, as well as limbic neuronal injury. Steroids, given as therapy or secreted from the adrenal gland upon treatment with ACTH, decrease the production and release of CRH in certain brain regions. Second, the hypothesis that ACTH directly influences limbic neurons via the recently characterized melanocortin receptors is considered, focusing on the effects of ACTH on the expression of CRH. Experimental data showing that ACTH potently reduces CRH expression in amygdala neurons is presented. This downregulation was not abolished by experimental elimination of steroids or by blocking their receptors and was reproduced by a centrally administered ACTH fragment that does not promote steroid release. Importantly, selective blocking of melanocortin receptors prevented ACTH-induced downregulation of CRH expression, providing direct evidence for the involvement of these receptors in the mechanisms by which ACTH exerts this effect. Thus, ACTH may reduce neuronal excitability in IS by two mechanisms of action: (1) by inducing steroid release and (2) by a direct, steroid-independent action on melanocortin receptors. These combined effects may explain the robust established clinical effects of ACTH in the therapy of IS.

West syndrome and other infantile epileptic encephalopathies--Indian hospital experience

Children with infantile epileptic encephalopathies comprising 3.5% of the Pediatric Neurology Clinic registrations in a tertiary care hospital were retrospectively analyzed. Data were retrieved from case records and analyzed for seizure semiology, prenatal and perinatal insults, developmental status and relevant investigations. The various therapeutic modalities and their influence on spasm frequency, long-term development and final seizure status were compared. The two primary outcome variables analyzed included final seizure status and developmental outcome. Of the 94 infantile epileptic encephalopathies, West syndrome was the commonest (55.3%), of which two thirds were symptomatic. Etiological factors were prenatal in 66.6% and perinatal in 33.3%. The initial response to ACTH was good in 54.5% with subsequent relapse in 27.8% and for prednisolone was 52.9 and 44.4%, respectively, compared to 25.3% spasms control with conventional antiepileptic drugs. Disease category of infantile epileptic encephalopathies evolved in 4, i.e. early myoclonic encephalopathy to West syndrome 1, early infantile epileptic encephalopathy to West syndrome 1, West syndrome to Lennox-Gastaut syndrome 2. Psychomotor retardation was seen in 88.2%, with 16.1% having normal development at onset of spasms. Microcephaly was associated with delayed development but did not influence final seizure outcome. Final seizure outcome was poor in children with delayed development at onset (adjusted odds ratio [OR]=4), delay in diagnosis >12 months (OR=2.27) and in children with Lennox-Gastaut syndrome (OR=4.75). ACTH/prednisolone and antiepileptic treatment versus antiepileptics alone showed a good final seizure response in 36.6% versus 20%. Development on follow up was delayed in children with initial psychomotor retardation (OR=23.4) and abnormal electroencephalogram (OR=7.46). Perinatal factors constituted one third of symptomatic West syndrome. The use of ACTH/corticosteroids resulted in good initial spasm control though final seizure outcome and development were unaffected. Prednisolone had similar response to ACTH in spasm control but higher subsequent relapse rate. Vigabatrin was useful though often unaffordable. The identification of a neurometabolic etiology, though uncommon, has significant therapy implications. Delay in diagnosis was common and negatively influenced final seizure outcome.

National survey of West syndrome in Taiwan

In the fall of 2000, the Taiwan Child Neurology Society performed a retrospective survey of West syndrome that occurred in 1998 and 1999 in Taiwan. Questionnaires were sent to the child neurologists in 15 major teaching hospitals or medical centers throughout Taiwan. There were totally 41 cases in these 2 years. Among these 41 cases, 35 had complete data and were enrolled for analysis. The male to female ratio was 1:1.19. The mean age of onset was 6.0+/-4.9 months old. Twenty nine percent were classified as cryptogenic and 71% were symptomatic. Adrenocorticotropic hormone (ACTH) was given to 40% of these patients. The initial response rate was 78.6% and the recurrence rate was 36.4%. For those patients not receiving ACTH, vigabatrin and valproic acid were two of the most common choices. At the final visit, 37% patients remained seizure-free, 29% were still suffering from the same seizure, and 34% changed to other seizure types. The final developmental status was normal in 14%, mildly retarded in 20%, and moderate to severely retarded in 66% of the patients.

How do the many etiologies of West syndrome lead to excitability and seizures? The corticotropin releasing hormone excess hypothesis

West syndrome (WS) is associated with diverse etiological factors. This fact has suggested that there must be a 'final common pathway' for these etiologies, which operates on the immature brain to result in WS only at the maturational state present during infancy. Any theory for the pathogenesis of WS has to account for the unique features of this disorder. For example, how can a single entity have so many etiologies? Why does WS arise only in infancy, even when a known insult had occurred prenatally, and why does it disappear? Why is WS associated with lasting cognitive dysfunction? And, importantly, why do these seizures--unlike most others--respond to treatment by a hormone, ACTH? The established hormonal role of ACTH in human physiology is to function in the neuroendocrine cascade of the responses to all stressful stimuli, including insults to the brain. As part of this function, ACTH is known to suppress the production of corticotropin releasing hormone (CRH), a peptide that is produced in response to diverse insults and stressors.The many etiologies of WS all lead to activation of the stress response, including increased production and secretion of the stress-neurohormone CRH. CRH has been shown, in infant animal models, to cause severe seizures and death of neurons in areas involved with learning and memory. These effects of CRH are restricted to the infancy period because the receptors for CRH, which mediate its action on neurons, are most abundant during this developmental period. ACTH administration is known to inhibit production and release of CRH via a negative feedback mechanism. Therefore, the efficacy of ACTH for WS may depend on its ability to decrease the levels of the seizure-promoting stress-neurohormone CRH.This CRH-excess theory for the pathophysiology of WS is consistent not only with the profile of ACTH effects, but also with the many different 'causes' of WS, with the abnormal ACTH levels in the cerebrospinal fluid of affected infants and with the spontaneous disappearance of the seizures. Furthermore, if CRH is responsible for the seizures, and CRH-mediated neuronal injury contributes to the worsened cognitive outcome of individuals with WS, then drugs which block the actions of CRH on its receptors may provide a better therapy for this disorder.

What are the reasons for the strikingly different approaches to the use of ACTH in infants with West syndrome?

A large body of experience has been compiled in different countries, documenting the efficacy of adenocorticotropic hormone (ACTH) for infantile spasms. This is important, because it may serve as a key for understanding this disorder, as well as for designing better medicines. However, significant discrepancies exist among studies originating in different countries regarding the relative efficacy of small or large ACTH doses. These differences may be caused by a number of factors, including potential genetic or environmental-related differences in the biology of the disorder or associated genetic components that determine responsiveness to ACTH. In addition, striking differences in the preparations used around the world may be responsible. These include bio-availability and extent of blood brain barrier penetration, efficacy in activating the efficacy-mediating 'ACTH receptors', the presence in certain preparations of competing analogs, and others. These issues should not detract from the overall agreement that ACTH might be the most useful medication currently available to treat WS.

Treatment of epilepsy in the multiply handicapped

The medical management of epilepsy in the multi-handicapped patient requires careful evaluation, classification, and pharmacologic treatment. It is estimated that 20-40% of patients with mental retardation and cerebral palsy have epilepsy. This review reports the clinical trial data and personal experience related to the use of newer AEDs in the chronic management of epilepsy syndromes in children and adults, as well as information available on the treatment of seizures in individuals with mental retardation and associated handicaps. Furthermore, clusters of seizures, prolonged seizures and status epilepticus are more commonly seen in the multiply handicapped and mentally retarded population and require special attention. The new antiepileptic drugs felbamate, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, tiagabine, topiramate, vigabatrin and zonisamide show specific advantage in some multiply handicapped patients, be it for seizure control or medication tolerance. Furthermore, new modalities of treatment for prolonged seizures allow better efficacy both outside of hospital and within hospital facilities. The treatment of epilepsy in multi-handicapped and retarded adults and children has significantly advanced in the past few years, and much of this improvement can be attributed to improved knowledge and monitoring of new antiepileptic drugs. Conventional anticonvulsants remain first line therapy for most clinicians, but newer AEDs must broaden the therapeutic option and do allow improved therapy for some multiply handicapped patients.

West syndrome in tuberous sclerosis complex

West syndrome occurs commonly in children with tuberous sclerosis complex and is associated with a grave prognosis for cognitive and seizure outcomes. We sought to determine the epilepsy outcome of children with tuberous sclerosis complex and West syndrome and whether EEG, MRI, or steroid therapy duration were different in those whose epilepsy improved compared with those with intractable seizures. Seventeen patients with tuberous sclerosis complex and West syndrome were identified. For each patient, two sets of clinical evaluations, EEG and MRI data, and treatment information separated by at least 12 months were obtained. The patients were divided into two seizure outcome groups. EEG, MRI, and treatment data were compared between the groups. The intellectual deficiency was either severe (76%) or moderate (24%). Seizure control improved in 10 and worsened in seven, without mortality (follow-up range = 12-216 months). No significant differences in EEG background, MRI findings, or steroid treatment duration were evident between the groups. The difference in EEG-sleep approached statistical significance (P = 0.06). Our findings did not confirm reports of high mortality and poor epilepsy outcome in intellectually deficient children with West syndrome and tuberous sclerosis complex. EEG sleep was the best indicator of seizure control and approached statistical significance. The duration of steroid therapy had no influence on seizure control.

[West syndrome: clinical and electroencephalographic follow up of 70 patients and response to its treatment with adrenocorticotropic hormone, prednisone, vigabatrin, nitrazepam and valproate]

In a retrospective study we assessed the outcome of the criptogenic and symptomatic forms of West syndrome and evaluated the efficacy of adrenocorticotropic hormone, vigabatrin, prednisone, valproate and nitrazepam in the spasms control. Seventy patients were follwed up by 2 years. Twelve (17%) were criptogenics and 58 (83%) symptomatics. In criptogenic group significantly more patients were in regular school classes and with normal motor development, better control of seizure, less tendency to evoluate to Lennox Gastaut syndrome and 83. 3% had control of spasms (72.4% of patients from symptomatic group had control of spasms). Adrenocorticotropic hormone and vigabatrin were the most efective drugs, with 68.75% and 60% of spasms control, respectivelly, when used as first line of therapy and 75% and 50%, respectivelly, as second line of therapy.

The descriptive epidemiology of infantile spasms among Atlanta children

PURPOSE

To determine the population-based epidemiology of infantile spasms (IS) among Atlanta children.

METHODS

By using data from a cross-sectional, population-based surveillance system that included 21 EEG laboratories, we identified children born in 1975-1977 in metropolitan Atlanta with IS. Cumulative incidence up to age 2 years was estimated from the number of children with IS born in the study area in 1975-1977, and age-specific prevalence was calculated from the number of children previously diagnosed with IS who lived in the study area at age 10 years. Data regarding coexisting disabilities were available from the surveillance system for developmental disabilities.

RESULTS

The cumulative incidence of IS was 2.9/10,000 live births; half of the children with IS had cryptogenic IS. The age-specific prevalence of IS was 2.0/10,000 among 10-year-old children. Eighty-three percent of 10-year-old children with a history of IS had mental retardation (MR, IQ < or =70); 56% of children with a history of IS had profound MR (IQ <20). Developmental outcome did not differ between the children with cryptogenic IS and those with symptomatic IS. Among the 10-year-old children with profound MR who were living in Atlanta at age 10 years, 12% had a history of IS. Fifty percent of children with IS developed Lennox-Gastaut syndrome (LGS) before age 11 years.

CONCLUSIONS

The syndrome of IS is rare in the general population, yet a significant percentage of all children with profound MR and severe childhood epilepsy syndromes in the general population have a history of IS.

The origin of hypsarrhythmia and tonic spasms in West syndrome: evidence from a case of porencephaly and hydrocephalus with focal hypsarrhythmia

We report on a 3-year-old girl with West syndrome and with focal hypsarrhythmia. The left hemisphere of the patient was virtually completely defective and continuous hypsarrhythmia was only seen in the residual right frontal cortex, where an interictal single photon emission computed tomography (SPECT) showed hyperperfusion. Despite a focal epileptic pattern, the tonic spasms were quite symmetrical. In our patient, spasms might not require the sensorimotor cortex, but the brainstem containing the descending pathways that control spinal reflexes and other infratentorial structures seem to be essential for the occurrence of spasms. This is in accordance with the result of an ictal SPECT that showed hyperperfusion of the brainstem and cerebellum. These findings suggest that hypsarrhythmia originates from cortical lesions, while subcortical structures may be primarily responsible for the tonic spasms in this patient.

Long-term follow-up study of vigabatrin in pretreated children with West syndrome

A multicentre, long-term, open-label, add-on study of vigabatrin was undertaken in 23 pretreated children with infantile spasms. After 3 months of vigabatrin therapy 11 of the 23 patients had become seizure-free. At this time two-thirds of these 11 children still received other antiepileptic drugs (AEDs) in addition to vigabatrin (mostly valproic acid and/or dexamethasone). After a mean follow-up time of 5 1/4 years (range: 4 1/4-6 1/2) 72% of 18 evaluable patients (two children died, three were lost to follow-up) revealed seizure freedom for at least 1 year. The mean duration of vigabatrin therapy had been 2 1/2 years (range: 2 weeks to 4 3/4 years). Two-thirds of the 18 children continued to take AEDs, three of them undergoing vigabatrin monotherapy. Relapses of infantile spasms had occurred in 14% of the children. The rate of vigabatrin side effects (10%) was low. At follow-up, the EEG of 13 and the 18 patients demonstrated focal or multifocal epileptic discharges. Fifty-five percent had developed another epilepsy (focal epilepsy, secondary generalized epilepsy or myoclonic-astatic epilepsy). With respect to mental functions, three children were normal or slightly retarded, four showed moderate retardation and 11 revealed severe or very severe retardation. This long-term result is comparable to that in ACTH studies with unselected patients. The conclusions are: (1) vigabatrin is an effective drug for the short-term and long-term treatment of refractory infantile spasms; (2) the relapse rate is low; (3) vigabatrin is well tolerated; (4) with respect to secondary epilepsies and mental functions the long-term outcome in these pretreated children is similar to that in earlier studies with ACTH or corticosteroids.

Analysis of childhood epileptic encephalopathies with regard to etiological and prognostic factors

To analyse the clinical characteristics of patients with childhood epileptic encephalopathies, a retrospective study was carried out on paediatric neurology clinic records of a tertiary hospital. Forty-five children with childhood epileptic encephalopathies were identified. Patients were classified according to the international classification of epilepsies and epileptic syndromes, data were collected regarding age at onset, perinatal problems, presence of psychomotor retardation, radiological findings, etiology and response to therapy. Characteristics of responders versus non-responders were compared. The majority had West syndrome (29/45 or 64.4%). Of the total, 37/45 or 82.2% were symptomatic. The etiologic factors identified included perinatal problems in 24/45 or 53.3%, one patient with tuberous sclerosis and one with Aicardi's syndrome. Psychomotor retardation was seen in 95.5%. Cranial CT scan was normal in 11/26 or 42.3%. Abnormalities included infarcts (4/26), generalised atrophy and hydrocephalus (3/26), porencephalic cysts (2/26) and agenesis of corpus callosum, tuberous sclerosis, gliosis and subdural effusion (one each). Mean follow-up was 18 months and 71.4% responded to ACTH. There was no significant difference between responders and non-responders.

West syndrome: etiological and prognostic aspects

West syndrome is a multi-etiological condition. Recent progress in perinatal medicine and the recent development of new neuroimaging techniques may have changed the etiological panorama of West syndrome. Our recent study has disclosed an increasing percentage of the perinatal group and a decreasing percentage of the doubtful group. The increase of the perinatal group is due to an increased proportion of very low-birthweight infants and periventricular leucomalacia (PVL). Among various etiological factors added to the long list of causes of West syndrome, focal cortical dysplasia is another newly emerging etiological factor associated with this syndrome. Patients with unilateral focal dysplasia more commonly have partial seizures, but may show infantile spasms transiently during infancy. They may have partial seizures preceding, in combination with or following infantile spasms. Follow-up MRI is necessary to detect delayed myelination because it is not disclosed at common ages of onset of this syndrome. PET is useful to further differentiate the cryptogenic group. Although West syndrome is regarded as one of the intractable epilepsies, the prognosis differs widely according to etiology. Follow-up PET is also useful to predict seizure and psychomotor prognosis.

West syndrome: cerebrospinal fluid nerve growth factor and effect of ACTH

West syndrome is a strictly age-limited encephalopathy of early infancy with unknown pathogenesis. It is often progressive, leading to mental retardation. Neurotrophic factors are important for the regulation of neuronal survival and differentiation, and their expression is influenced by hormones. Levels of beta-nerve growth factor in the cerebrospinal fluid were examined by two-site enzyme-linked immunosorbent assay method. Human antigen was used as a standard. We present data on largely normal levels of nerve growth factor in the cerebrospinal fluid of infants with cryptogenic etiology, but low or negligible levels in infants with symptomatic etiology, and very high levels in infants with symptomatic postinfectious etiology. Treatment with ACTH led to a greater increase in patients with a good response than in those with a poor response. Low nerve growth factor in patients with symptomatic infantile spasms possibly reflects massive neuronal death. The regression seen in these infants and their poor response to ACTH therapy may be due in part to lack of growth factors supporting neuron survival. This study, previously only demonstrated in animal models, is the first to depict nerve growth factor gene activity in humans as modulated by steroids.

How do cryptogenic and symptomatic infantile spasms differ? Review of biochemical studies in Finnish patients

Infants with cryptogenic infantile spasms seem to differ from those with symptomatic spasms in having a higher cerebrospinal fluid corticotropin content, different levels of corticotropin release after exogenous vasopressin, higher serum levels of progesterone, higher dehydroepiandrosterone: androstenedione ratio (during corticotropin therapy), a higher cerebrospinal fluid gamma-aminobutyric acid content, and higher cerebrospinal fluid nerve growth factor concentrations. It remains to be seen whether the biochemical differences between the two groups are specific or only happen to correlate with the early brain damage. However, these differences would explain many pathophysiologic features of infantile spasms.

An MRI study of the myelination pattern in West syndrome

Using magnetic resonance imaging (MRI), we studied the myelination of the brains of 8 patients with West syndrome. All cases were symptomatic, 2 having severe asphyxia, 1 lissencephaly, 1 Leigh encephalopathy, 2 tuberous sclerosis, 1 multiple anomalies and 1 microcephaly. Myelination of the pons, cerebellum, thalamus, internal capsules, optic radiation, centrum semiovale and cerebral white matter was separately assessed. The 2 cases with tuberous sclerosis exhibited normal myelination patterns, although asymmetry of the cerebral white matter was noted. These cases had a moderate degree of mental retardation and persistent seizures. The other 6 cases exhibited a marked delay of myelination throughout the central nervous system except for the midbrain. These cases had severe psychomotor retardation and persistent seizures. Although the difference in the outcome may simply reflect the different etiological disorders, these results suggest that the myelination pattern is related to the psychomotor retardation but not to the severity of the seizures in West syndrome. Atrophy of the corpus callosum developed during ACTH therapy and disappeared after the therapy. It was thus suggested that the callosal atrophy caused by the ACTH therapy was reversible.