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Background: Two pathologic subtypes based on the presence or absence of balloon cells have been described in cortical dysplasia of Taylor (CDT)., Objective: To determine whether the pathologic subtype has any distinct clinical or MRI features that are relevant to management., Methods: The histopathologic, clinical, and MRI features of 34 children with CDT who underwent epilepsy surgery at Miami Children's Hospital from 1990 to 2001 were investigated., Results: Bizarre neuronal cytomegaly was the primary pathologic feature of 15 patients with the dysplasia-only subtype, and 19 cases showed additional characteristics including balloon cells and marked white matter abnormalities. Both groups presented with severe intractable epilepsy of very-early-onset, multiple daily seizures, cognitive disability, and focal neurologic deficits. The dysplasia-only subtype had higher rates of neonatal onset, hemiparesis, and severe mental retardation (p < 0.05). The MRI features of focal cortical thickening with associated cortical T2 signal change showed excellent sensitivity (94%) and reasonable specificity (73%) for the diagnosis of the balloon cell subtype. The overall surgical outcome was 59% seizure freedom at 2 years., Conclusions: Children with cortical dysplasia of Taylor type have in common a very-early-onset, severe epilepsy with neurologic co-morbidity. Patients with the non-balloon cell pathologic subtype have a more severe phenotype. A trend toward a better outcome in the balloon cell group suggests that preoperative identification of these subtypes may impact surgical planning.

The aim of this study was to adapt the Australian Quality of Life in Childhood Epilepsy Questionnaire (QOLCE) and determine its psychometric properties in a North American population. Participants were North American families with children diagnosed with epilepsy. Parents were asked to complete the American QOLCE (USQOLCE) and the Child Health Questionnaire (CHQ). Seventy-one families completed the USQOLCE. The internal consistency reliability of the subscales was good. USQOLCE subscales correlated highly with theoretically similar subscales contained in the CHQ. Theoretically dissimilar subscales on the two instruments did not correlate as well. USQOLCE correlated significantly with a parental rating of seizure severity and an independent measure of degree of postoperative seizure control. This study demonstrated that the USQOLCE is suitable for a North American population with evidence of its reliability and validity including its sensitivity to seizure burden.

Purpose: Children with tuberous sclerosis complex (TSC) benefit from excisional surgery if seizures can be localized to a single tuber. We evaluated the role of noninvasive studies to localize the epileptogenic tuber/region (ET/R) and the outcome of focal resection., Methods: We identified 21 children with TSC, ages 3 months to 15 years (mean 4.8 years). All had video-(electroencephalogram) EEG and magnetic resonance imaging (MRI) scans, and 18 also had ictal single photon emission-computed tomography (SPECT) studies. An ET/R was localized in 17 patients. Thirteen patients underwent resection guided by intraoperative electrocorticography (n = 7) or subdural monitoring (n = 6)., Results: Interictal EEG revealed a principal spike focus (PSF) that corresponded to the ET/R in 14 children. In seven, PSFs occurred in rhythmic runs. PSFs were not observed remote from the ET/R. Focal polymorphic slowing and attenuation occurred in the region of the PSF in 11 patients. Sixteen patients demonstrated an ictal focus corresponding to the ET/R. Ictal SPECT revealed focal hyperperfusion correlating with the ET/R in 10 patients. Although the MRIs in all children revealed multiple tubers, the ET/R corresponded to a large discrete tuber in 8 patients and a calcified tuber in 13 patients. Patchy calcified tubers were also seen elsewhere in six patients. At a mean follow-up of 26 months, 9 of the 13 children who underwent surgery were seizure-free, one had greater than 75% reduction in seizures, two were unchanged, and one was lost to follow-up. New seizures developed in one child from a contralateral tuber., Conclusions: Surgical resection of an ET/R alleviates seizures in most children with TSC and intractable epilepsy. The scalp EEG and MRI help define the ET/R and improve case selection when ictal SPECT is nonlocalizing.

Introduction and Objectives: The pathological findings in surgical material from children with refractory epilepsy has not offered yet a clear understanding of its role in this condition. The objective of this paper is to report our findings to further expand our knowledge about refractory epilepsy in children., Material and Methods: Results of microscopic examination of the surgical specimen obtained from 80 children, ages 12 or younger, who had surgery for intractable epilepsy at Miami Children's Hospital between 1990 and 1996 were reviewed., Results: Examination was normal only in one. The rest revealed ectopic neurons (1), dysplastic cells with ectopic neurons (2), dyslamination with large neurons (7), dyslamination with ectopic neurons (18), dyslamination with dysplastic cells (10), pachygyria (2), encephalomalacia (9), gliosis with ectopic neurons (10), gliosis without ectopic neurons (3), developmental ectodermal tumor (6), ganglioglioma (2), tumors (3), and Rasmussen encephalitis (4). Lesions were located to the temporal lobe in 34 children. CONCLUSIONS. Extratemporal lesions are more frequent than temporal one, including hyppocampal sclerosis. Ectopic neurons, the most frequent pathological findings, rather than a cause of seizure may be a marker other highly epileptogenic cortical malformations.

The recent advances in the surgical treatment of epilepsy have resulted in great improvement in the overall outcome of these patients. The pediatric group has probably benefited the most as patients who previously were not candidate for this form of treatment are now able to undergo epilepsy surgery with results which are as good as those of adults. In fact, children may now benefit the most, as the control of their epilepsy and our ability to stop their anticonvulsants may allow them to better develop from a psychosocial aspect. Also, because of their plasticity, young children may tolerate surgery involving loss of eloquent cortex without subsequent permanent deficits. The most recent reported results from different centers indicate that 68-90% of patients undergoing temporal lobectomy remain seizure free while the percentage of patients remaining seizure free after extratemporal resections is approximately 50-66%. However, one of the problems with these results is that they vary significantly from one center to another because of the methodology used to evaluate results and the selection of patients depending on the strength of the centers. At present we do not have an optimal method to evaluate results of epilepsy surgery that takes in consideration not only seizure control but also psychosocial outcome. It is our goal to develop such method which will ultimately help us identify the best surgical candidates and predict their outcome.

The relation between hyperventilation (HV)-induced high-amplitude rhythmical slowing (HIHARS) and altered responsiveness without generalized spike and wave activity has not been clearly defined. To test whether altered responsiveness is a nonspecific physiologic response rather than a symptom of generalized epilepsy, we assessed verbal recall ability and motor response testing in 12 healthy nonepileptic children (mean age 9.6 years). Both tasks were administered as a baseline before HV, during HV but before onset of EEG slowing, and during HIHARS. Verbal recall and motor responsiveness remained unchanged during baseline and HV before onset of slowing. During HIHARS, all children exhibited impaired verbal recall (p < 0.005) and 8 of 12 failed to respond to repeated auditory clicks (p < 0.005). Our findings indicate that in a normal setting, responsiveness may be impaired during HV in healthy nonepileptic children.

A 32-month-old child presented in status epilepticus (SE) involving the left side of the body. Fast spin-echo magnetic resonance imaging (FSE-MRI) with hippocampal volumetry performed < or = 24 h after the seizure showed increased T2 signal of the right hippocampus, but no atrophy. Complex partial seizures (CPS) appeared at age 33 months, and three more episodes of SE occurred between 33 and 37 months of age. Follow-up FSE-MRI at 34 and at 45 months of age demonstrated progressive hippocampal atrophy with resolution of the increased T2 signal. Her CPS became intractable and, at age 51 months, she underwent right temporal lobectomy. In the ensuing 5 months, she has had only one major motor seizure. This case demonstrates that acute increased hippocampal T2 signal intensity can occur soon after SE and hippocampal sclerosis (HS) may become evident within months in the setting of recurrent early childhood SE. This observation may support the hypothesis that early childhood SE can lead to HS. Furthermore, this case suggests that years of temporal lobe CPS may not be necessary for development of HS.

Surgical resection for localization-related epilepsy has recently become a generally accepted treatment in children. Evidence of the poor outcome in natural history studies of temporal lobe epilepsy in childhood initiated consideration of surgical intervention. Subsequent favorable outcome following surgery was encouraging. A number of variables differentiate adults with focal seizures from children. Evolving biologic factors modify the clinical and electroencephalographic expression of seizures in childhood. The pathologic substrate is different, and there is a higher incidence of extratemporal epilepsy. Chronic seizures beginning under age 2 years rarely remit, especially when associated with a demonstrable structural lesion. Behavioral consequences of chronic seizures are significant and become a major problem by adolescence if seizures are not controlled. Early surgery results in superior functional outcome, although subtle deficits persist postoperatively. Surgical outcome is as favorable as in adults with improvements in behavioral status and socialization. Abundant data exist to more adequately assess the benefits and risks of surgery in children so that intervention is not deferred longer than it needs to be.

Noninvasive assessment of children with chronic epilepsy is often imprecise and localization of seizure foci requires intracranial electroencephalographic monitoring. Subdural electrodes provide coverage of large areas of neocortex and are ideally suited for evaluating children with intractable epilepsy and to functionally map critical cortex. This report discusses the role of subdural electroencephalography in the evaluation of childhood epilepsy.

Children with well-localized medically resistant seizures are often referred for surgical therapy. In young children, at least three maturational issues play a significant role in the selection process and long-term outcome. First, the early years are a time of exceptionally rapid brain development leading to dynamic changes in the electroencephalogram and the clinical expression of seizures. Many early-onset seizure presentations are also associated with catastrophic outcomes, developmental arrest, or regression. Second, the immature limbic system may be vulnerable to stresses operating in early life, although the consequences may not become apparent for many years. Third, in comparison to the adult, the child's nervous system typically exhibits superior functional recovery after lesioning, but the process of sparing and recovery is often incomplete. An understanding of how these neurobiologic factors influence developmental outcome will ultimately lead to greater selectivity of candidates for early surgery and to improved long-term prognosis.

We assessed the value of therapeutic reevaluation and additional pharmacotherapy in medically intractable children referred for epilepsy surgery. In 21 children with antiepileptic drug treatment omissions, correcting the omission was ineffective in 19 (90%). Two children (10%), both of whom had structural lesions, achieved significant seizure control with high-dose carbamazepine monotherapy. Therapeutic reevaluation is indicated in all medically intractable children prior to epilepsy surgery.

Conventional cortical stimulation based on pulses of fixed duration briefer than the chronaxie rarely elicit responses in infants and young children. We developed a stimulation paradigm that relies on increments in both stimulus intensity and pulse duration. This approach ensures that stimulation parameters converge to the chronaxie by mathematically minimizing the energy required to elicit a response. In six patients, this paradigm successfully elicited clinical responses and/or afterdischarges at thresholds 5-8 mA below the standard paradigm and at up to 64% lower energy levels. Furthermore, three patients under age 5 years who did not respond to maximal fixed duration stimulation demonstrated afterdischarges and clinical responses when longer pulse durations were utilized. These findings indicate that a paradigm based on dual increments is effective for cortical mapping in children. Furthermore, by ensuring responses at lower energy levels, it may be more efficient for mapping the cortex at all ages.

The authors describe the use of intraoperative US for directing placement of depth electrodes for the localization of seizure foci prior to temporal lobectomy. They used this technique in seven patients (six undergoing temporal and one frontal resection), and encountered no complications.

The pitfalls and difficulties in accurately localizing seizure foci are reviewed. Basic issues regarding modeling, volume conduction, inhomogeneities, and corticocortical propagation are discussed, and the limitations of scalp and intracranial recordings are outlined. The ambiguities in interpreting patterns and their significance are highlighted with a concluding commentary on pitfalls in defining the epileptogenic region.

We present a modified EEG montage that detects small interchannel time differences and assists in localizing the epileptogenic focus. Regions with apparently synchronous epileptic discharges are displayed simultaneously in referential and subtraction derivations. The subtraction derivation is a bipolar configuration of two regions of interest that are not necessarily adjacent. The referential derivation reveals the polarity, voltage, and morphology of the two discharges, and the subtraction derivation detects asynchrony; the combined reference-subtraction derivation thus indicates the region that is activated first.

There is little experience with excisional surgery for drug-resistant partial seizures in very young patients. We describe our experience with 5 infants under 1 year of age with malignant partial seizures and deteriorating developmental status. All were experiencing frequent daily seizures that did not respond to 1st-line antiepileptic medications at high therapeutic serum levels and considerable medication toxicity. Three infants had complete resection of epileptic tissue (frontal corticectomy and prefrontal lobectomy) and are seizure-free. Two underwent partial resection (lateral temporal lobectomy, frontal corticectomy with anterior callosotomy) and have experienced a significant reduction in seizure frequency. Surgery did not result in any significant neurologic deficit or lead to compromise of developmental status. From these data, we tentatively conclude that excisional surgery can be performed safely in selected infants with medically uncontrolled malignant partial seizures and may significantly improve long-term seizure status. Referral to a tertiary center specializing in early childhood epilepsy surgical evaluation may be considered in these circumstances.

Differentiating seizures from pseudoseizures frequently is challenging in very young children manifesting repetitive, stereotypic behavior. Using video electroencephalographic recording, we evaluated 60 patients, younger than 10 years of age, with episodic signs and symptoms believed to be seizures despite repeatedly normal routine electroencephalograms. Nine patients (15%) had simple partial and atypical absence seizures. Twenty-four patients (40%) had pseudoseizures presenting as rhythmic movements or staring. Pseudoseizure frequency was greater than the frequency of true seizures; brief staring episodes were common. Motor pseudoseizures usually were of longer duration than true seizures and could be brought on with verbal encouragement. Furthermore, the stereotypic motor presentations were quite different from those of true motor seizures but were difficult to recognize from historic, clinical, and routine electroencephalographic data. Symptomatic patients can be clinically diagnosed by analyzing confirmed episodes with video electroencephalography.

In a retrospective study involving several medical centers we identified 52 patients under age 5 years who met the adult clinical criteria for brain death and had at least one EEG with electrocerebral silence. Of the 52 patients, 31 died spontaneously and 21 were disconnected from the respirator. Repeat EEGs were obtained in 28 patients, and in all electrocerebral silence persisted. The study suggests that clinical criteria similar to those used for adults in the determination of brain death can also be applied to children above age 3 months and that a single EEG with electrocerebral silence is sufficient to confirm brain death in this age group.

A transient expressive aphasia associated with focal slowing in the electroencephalogram, is described in a patient with documented Mycoplasma infection. The hypothesis that ischemia is a mechanism for the transient clinical findings is considered in relation to animal studies.

A patient with the typical craniofacial features and clinical course of Miller-Dieker syndrome (MDS) was found on autopsy to have focal pachygyria rather than lissencephaly. The brainstem and cerebellum were hypoplastic, but thalami and basal ganglia were normal. We believe that MDS is a syndrome in which multiple specific pathways of neuronal migration are affected selectively, such as migration to the neocortex, migration via corpus pontobulbare, and cerebellar migration. However, another migration pathway (via corpus gangliothalamicum) is spared.

Neonatal sleep myoclonus is a benign syndrome characterized by myoclonic jerks occurring only during sleep and presenting in the first month of life. There are no associations with abnormal development, neurologic deficits, or seizures. The electroencephalogram is normal and has no correlation with the myoclonic jerks. The myoclonus is present in all sleep states although its frequency is state dependent and greatest during quiet sleep. It is not associated with an arousal response as previously thought. Transient serotonin imbalance and genetic factors might play a role in the pathogenesis of this disorder.

We describe the clinical, radiologic, and EEG features of 3 children who had dysplastic gangliocytomas of the cerebral hemispheres and drug resistant partial seizures that began in infancy. Following cortical resection, 2 are seizure-free and the third almost seizure-free. The dysplastic gangliocytoma may be an important and surgically remediable cause of very early malignant partial seizures.