Temporal lobe epilepsy in early childhood

Motor seizure semiology

Motor semiology is a major component of epilepsy evaluation, which provides essential information on seizure classification and helps in seizure localization. The typical motor seizures include tonic, clonic, tonic-clonic, myoclonic, atonic, epileptic spasms, automatisms, and hyperkinetic seizures. Compared to the "positive" motor signs, negative motor phenomena, for example, atonic seizures and Todd's paralysis are also crucial in seizure analysis. Several motor signs, for example, version, unilateral dystonia, figure 4 sign, M2e sign, and asymmetric clonic ending, are commonly observed and have significant clinical value in seizure localization. The purpose of this chapter is to review the localization value and pathophysiology associated with the well-defined motor seizure semiology using updated knowledge from intracranial electroencephalographic recordings, particularly stereoelectroencephalography.

Congruence and Discrepancy of Interictal and Ictal EEG With MRI Lesions in Pediatric Epilepsies

Purpose. To evaluate the congruence or discrepancy of the localization of magnetic resonance imaging (MRI) lesions with interictal epileptiform discharges (IEDs) or epileptic seizure patterns (ESPs) in surface EEG in lesional pediatric epilepsy patients. Methods. We retrospectively analyzed presurgical MRI and video-EEG monitoring findings of patients up to age 18 years. Localization of MRI lesions were compared with ictal and interictal noninvasive EEG findings of patients with frontal, temporal, parietal, or occipital lesions. Results. A total of 71 patients were included. Localization of ESPs showed better congruence with MRI in patients with frontal lesions (n = 21, 77.5%) than in patients with temporal lesions (n = 24; 40.7%) (P = .009). No significant IED distribution differences between MRI localizations could be found. Conclusions. MRI lesions and EEG findings are rarely fully congruent. Congruence of MRI lesions and ESPs was highest in children with frontal lesions. This is in contrast to adults, in whom temporal lesions showed the highest congruency with the EEG localization of ESP. Lesional pediatric patients should be acknowledged as surgical candidates despite incongruent findings of interictal and ictal surface EEG.

Downregulation of hyperpolarization-activated cyclic nucleotide-gated channels (HCN) in the hippocampus of patients with medial temporal lobe epilepsy and hippocampal sclerosis (MTLE-HS)

Changes in the expression of HCN ion channels leading to changes in I_h function and neuronal excitability are considered to be possible mechanisms involved in epileptogenesis in kinds of human epilepsy. In previous animal studies of febrile seizures and temporal lobe epilepsy, changes in the expression of HCN1 and HCN2 channels at different time points and in different parts of the brain were not consistent, suggesting that transcriptional disorders involving HCNs play a crucial role in the epileptogenic process. Therefore, we aimed to assess the transcriptional regulation of HCN channels in Medial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) patients. This study included eight nonhippocampal sclerosis patients and 40 MTLE-HS patients. The mRNA expression of HCN channels was evaluated by qRT-PCR, while the protein expression was quantitatively analyzed by Western blotting. The subcellular localization of HCN channels in the hippocampus was explored by immunofluorescence. We demonstrated that the mRNA and protein expression of HCN1 and HCN2 are downregulated in controls compared to that in MTLE-HS patients. In the hippocampal CA1/CA4 subregion and GCL, in addition to a large decrease in neurons, the expression of HCN1 and HCN2 on neuronal cell membranes was also downregulated in MTLE-HS patients. These findings suggest that the expression of HCN channels are downregulated in MTLE-HS, which indicates that the decline in HCN channels in the hippocampus during chronic epilepsy in MTLE-HS patients leads to the downregulation of I_h current density and function, thereby reducing the inhibitory effect and increasing neuronal excitability and eventually causing disturbances in the electrical activity of neurons.

Mesial Temporal Sclerosis in SCN1A-Related Epilepsy: Two Long-Term EEG Case Studies

Patients with temporal lobe epilepsy (TLE) due to mesial temporal sclerosis (MTS) are eligible candidates for resective epilepsy surgery. We report on 2 male patients aged 4 years with suspected TLE due to MTS who were referred for presurgical evaluation. Both patients came to medical attention within the first year of life suffering from febrile status epileptici and subsequent unprovoked seizures. The following years, moderate developmental delay was present. High-resolution magnetic resonance imaging confirmed hippocampal sclerosis. Continuous EEG video monitoring revealed seizure patterns contralateral to the MTS in both patients. Genetic analysis was performed as both the clinical presentation of the patients and EEG video monitoring findings were not consistent with the presence of the hippocampal sclerosis alone and revealed de novo mutations within exon of the SCN1A gene. Resective surgical strategies were omitted due to the genetic findings. In conclusion, both patients suffered from a dual pathology syndrome with ( a) TLE related to MTS resulting most likely from recurrent febrile status in early childhood and ( b) Dravet syndrome, which is most likely the cause of the febrile convulsions leading to the MTS in these 2 patients.

Long-term seizure outcomes after pediatric temporal lobectomy: does brain MRI lesion matter?

OBJECTIVE

There is emerging data that adults with temporal lobe epilepsy (TLE) without a discrete lesion on brain MRI have surgical outcomes comparable to those with hippocampal sclerosis (HS). However, pediatric TLE is different from its adult counterpart. In this study, the authors investigated if the presence of a potentially epileptogenic lesion on presurgical brain MRI influences the long-term seizure outcomes after pediatric temporal lobectomy.

METHODS

Children who underwent temporal lobectomy between 2007 and 2015 and had at least 1 year of seizure outcomes data were identified. These were classified into lesional and MRI-negative groups based on whether an epilepsy-protocol brain MRI showed a lesion sufficiently specific to guide surgical decisions. These patients were also categorized into pure TLE and temporal plus epilepsies based on the neurophysiological localization of the seizure-onset zone. Seizure outcomes at each follow-up visit were incorporated into a repeated-measures generalized linear mixed model (GLMM) with MRI status as a grouping variable. Clinical variables were incorporated into GLMM as covariates.

RESULTS

One hundred nine patients (44 females) were included, aged 5 to 21 years, and were classified as lesional (73%), MRI negative (27%), pure TLE (56%), and temporal plus (44%). After a mean follow-up of 3.2 years (range 1.2-8.8 years), 66% of the patients were seizure free for ≥ 1 year at last follow-up. GLMM analysis revealed that lesional patients were more likely to be seizure free over the long term compared to MRI-negative patients for the overall cohort (OR 2.58, p < 0.0001) and for temporal plus epilepsies (OR 1.85, p = 0.0052). The effect of MRI lesion was not significant for pure TLE (OR 2.64, p = 0.0635). Concordance of ictal electroencephalography (OR 3.46, p < 0.0001), magnetoencephalography (OR 4.26, p < 0.0001), and later age of seizure onset (OR 1.05, p = 0.0091) were associated with a higher likelihood of seizure freedom. The most common histological findings included cortical dysplasia types 1B and 2A, HS (40% with dual pathology), and tuberous sclerosis.

CONCLUSIONS

A lesion on presurgical brain MRI is an important determinant of long-term seizure freedom after pediatric temporal lobectomy. Pediatric TLE is heterogeneous regarding etiologies and organization of seizure-onset zones with many patients qualifying for temporal plus nosology. The presence of an MRI lesion determined seizure outcomes in patients with temporal plus epilepsies. However, pure TLE had comparable surgical seizure outcomes for lesional and MRI-negative groups.

Epilepsy Surgery in Children versus Adults

Epilepsy is one of the most common chronic neurological disorder affecting 6–7 per 1000 worldwide. Nearly one-third of patients with newly diagnosed epilepsy continue to have recurrent seizures despite adequate trial of more than two anti-seizure drugs : drug-resistant epilepsy (DRE). Children with DRE often experience cognitive and psychosocial co-morbidities requiring more urgent and aggressive treatment than adults. Epilepsy surgery can result in seizure-freedom in approximately two-third of children with improvement in cognitive development and quality of life. Understanding fundamental differences in etiology, co-morbidity, and neural plasticity between children and adults is critical for appropriate selection of surgical candidates, appropriate presurgical evaluation and surgical approach, and improved overall outcome.

Focal Seizures in Patients With SCN1A Mutations

The SCN1A gene has been implicated in the etiology of various forms of epilepsy. New research has linked this gene to specific types of epilepsy, all of which present in infancy or early childhood. This study examines the time course and pathology of pediatric patients who have a mutation in the SCN1A gene in order to open a discussion regarding the key trends of this form of epilepsy as well as important clinical considerations in management for patients who present with symptoms relating to the SCN1A mutations. We retrospectively examined 20 patients who presented to the clinic with focal seizures, as well as were positive for an SCN1A genetic mutation. Despite the small sample size, we were able to find important trends in the time course of the disorder as well as important areas of clinical practice that must be taken into consideration for these patients.

An evaluation of lateralizing signs in patients with temporal lobe epilepsy

Resective epilepsy surgery has been accepted as an effective treatment for patients with medically intractable temporal lobe epilepsy (TLE) to control the seizures and to limit cognitive dysfunction. Complete resection of the epileptic zone, and therefore the success of the surgery, depends on the identification of the seizure focus. Reliable lateralizing semiologic signs, together with other presurgical assessments, are of great importance for an accurate identification of the seizure focus. In this respect, this study evaluated the frequency of semiologic signs in medically intractable temporal lobe epilepsy (TLE) together with the lateralizing values and variations according to the age and gender groups. Two hundred seventy-three seizures of 55 patients of the Adult Epilepsy Monitoring Unit of Gazi University Faculty of Medicine with the diagnosis of medically intractable TLE, whose epileptic foci were detected through noninvasive presurgical procedures and seizures were controlled successfully after anterior temporal lobectomy (ATL), were analyzed retrospectively. Seizure semiologies of the patients were evaluated in terms of lateralizing values, and it was inquired whether age/gender causes any variation. Versive head rotation, unilateral dystonic limb posturing, asymmetric tonic limb posturing, and the combination of unilateral hand automatisms and dystonic posturing were determined as the semiologic signs with the highest lateralizing values (90-100%). While hand automatisms were observed frequently in the group with early seizure-onset age (onset age ≤ 2), asymmetric tonic limb posturing was detected as more frequent in the group with later seizure-onset age (onset age > 2; p < .005). In addition to this, semiologic signs were noted to be different between male and female groups; psychic and autonomic auras and ictal emotional signs were associated with women (p < .005).

Advances in radiofrequency ablation of the cerebral cortex in primates using the venous system: Improvements for treating epilepsy with catheter ablation technology

BACKGROUND

Pharmacology frequently fails for the treatment of epilepsy. Although surgical techniques are effective, these procedures are highly invasive. We describe feasibility and efficacy of minimally invasive mapping and ablation for the treatment of epilepsy.

METHODS

Mapping and radiofrequency ablations were performed via the venous system in eleven baboons and three dogs.

RESULTS

Mapping in deep cerebral areas was obtained in all animals. High-frequency pacing was able to induce seizure activity of local cerebral tissue in 72% of our attempts. Cerebral activity could be seen during mapping. Ablative lesions were deployed at deep brain sites without steam pops or sudden impedance rise. Histologic analysis showed necrosis at the sites of ablation in all primates.

CONCLUSION

Navigation through the cerebral venous system to map seizure activity is feasible. Radiofrequency energy can be delivered transvenously or transcortically to successfully ablate cortical tissue in this animal model using this innovative approach.

Surgery for childhood epilepsy

Approximately 60% of all patients with epilepsy suffer from focal epilepsy syndromes. In about 15% of these patients, the seizures are not adequately controlled with antiepileptic drugs; such patients are potential candidates for surgical treatment and the major proportion is in the pediatric group (18 years old or less). Epilepsy surgery in children who have been carefully chosen can result in either seizure freedom or a marked (>90%) reduction in seizures in approximately two-thirds of children with intractable seizures. Advances in structural and functional neuroimaging, neurosurgery, and neuroanaesthesia have improved the outcomes of surgery for children with intractable epilepsy. Early surgery improves the quality of life and cognitive and developmental outcome and allows the child to lead a normal life. Surgically remediable epilepsies should be identified early and include temporal lobe epilepsy with hippocampal sclerosis, lesional temporal and extratemporal epilepsy, hemispherical epilepsy, and gelastic epilepsy with hypothalamic hamartoma. These syndromes have both acquired and congenital etiologies and can be treated by resective or disconnective surgery. Palliative procedures are performed in children with diffuse and multifocal epilepsies who are not candidates for resective surgery. The palliative procedures include corpus callosotomy and vagal nerve stimulation while deep brain stimulation in epilepsy is still under evaluation. For children with "surgically remediable epilepsy," surgery should be offered as a procedure of choice rather than as a treatment of last resort.

Value of neuroimaging in epilepsy: An experience from Pakistan

Purpose:

To detect the possible structural brain lesions in the patients suffering from various kinds of epilepsy during the routine neuroimaging.

Materials and Methods:

Prospective study of 366 epileptic patients conducted at epilepsy clinic, Rawalpindi-Islamabad Pakistan in an outpatient setting. MRI or CT scan of the brain without contrast was advised in all patients to detect any underlying pathology.

Results:

A total 21.31% scans were found to be abnormal. Many cases of familial, idiopathic epilepsy and patients without any neurological deficit were found to have structural brain lesions, which might be responsible for their seizures.

Conclusion:

CT/MRI scan of the brain should be advised in all patients of epilepsy regardless of cause and type of epilepsy. The presence of neurological deficit should not be the sole indication for neuroimaging.

Temporal lobe epilepsy surgery in children versus adults: from etiologies to outcomes

Temporal lobe epilepsy (TLE) is the most common type of medically intractable epilepsy in adults and children, and mesial temporal sclerosis is the most common underlying cause of TLE. Unlike in the case of adults, TLE in infants and young children often has etiologies other than mesial temporal sclerosis, such as tumors, cortical dysplasia, trauma, and vascular malformations. Differences in seizure semiology have also been reported. Motor manifestations are prominent in infants and young children, but they become less obvious with increasing age. Further, automatisms tend to become increasingly complex with age. However, in childhood and especially in adolescence, the clinical manifestations are similar to those of the adult population. Selective amygdalohippocampectomy can lead to excellent postoperative seizure outcome in adults, but favorable results have been seen in children as well. Anterior temporal lobectomy may prove to be a more successful surgery than amygdalohippocampectomy in children with intractable TLE. The presence of a focal brain lesion on magnetic resonance imaging is one of the most reliable independent predictors of a good postoperative seizure outcome. Seizure-free status is the most important predictor of improved psychosocial outcome with advanced quality of life and a lower proportion of disability among adults and children. Since the brain is more plastic during infancy and early childhood, recovery is promoted. In contrast, long epilepsy duration is an important risk factor for surgically refractory seizures. Therefore, patients with medically intractable TLE should undergo surgery as early as possible.

Surgery for temporal lobe epilepsy in children: relevance of presurgical evaluation and analysis of outcome

OBJECT

The authors' goal in this paper was to retrospectively evaluate the relevance of the presurgical workup and the postoperative outcome in children (< 15 years) who undergo surgery for temporal lobe epilepsy (TLE).

METHODS

The authors performed a retrospective analysis of 68 patients (43 boys and 25 girls) who underwent resection for TLE between 2001 and 2010 at a single center and had a minimum postoperative follow-up of 12 months. Presurgical investigations included full clinical evaluation, interictal electroencephalography (EEG), and MRI in all cases; cognitive evaluation in patients older than 5 years; scalp video-EEG in 46 patients; and invasive EEG in 3 patients. Clinical evaluation included a careful assessment of ictal semiology (based on anamnestic reports or video-EEG review), with particular attention to early signs and/or symptoms suggestive of temporal lobe origin of the seizure. Microsurgical resections were performed within the anatomical limits of the temporal lobe, and surgical specimens were processed for histological examination. Postoperative assessment of seizure outcome (Engel classification system) and cognitive performance was conducted at regular intervals. The effect on postoperative seizure outcome (good = Engel Class I; poor = Engel Classes II-IV) of several presurgical and surgical variables was investigated by bivariate statistical analysis.

RESULTS

All patients had at least 1 early sign or symptom suggesting a temporal lobe origin of their seizures. Lateralized interictal or ictal EEG abnormalities were seen in all patients, and they were localized to the temporal lobe in 45 patients. In all cases MRI demonstrated a structural abnormality. Surgery consisted of a tailored anterior temporal lobectomy in 64 patients and a neocortical lesionectomy in 4 patients. Postoperatively, 58 patients (85%) were in Engel Class I. Variables significantly associated with a poor outcome were preoperative sensory motor deficit (p = 0.019), mental retardation (p = 0.003), MRI abnormalities extending outside the temporal lobe (p = 0.0018), history of generalized seizures (p = 0.01) or status epilepticus (p = 0.008), unremarkable histology (p = 0.001), seizures immediately postoperatively (p = 0.00001), and ipsilateral epileptiform activity on postoperative EEG (p = 0.005). At postoperative neuropsychological assessment, the percentage of patients with a pathological score at the final visit invariably decreased compared with that at the preoperative evaluation in all considered cognitive domains.

CONCLUSIONS

Among the study population, a surgical selection based on a noninvasive evaluation was possible in most patients. The invaluable information resulting from the rigorous noninvasive electroclinical and neuroimaging evaluation can lead to excellent surgical results without the use of invasive, time-consuming, and expensive diagnostic tools. The potential reduction of invasiveness-related risks, complexity, and costs of presurgical investigations should hopefully allow for an increase in the number of children with TLE who will receive surgery, particularly in centers with limited technological resources.

Focal epileptogenic lesions

The spectrum of focal epileptogenic lesions and their clinical manifestations in children differ substantially from those seen in adults. In adults, mesial temporal sclerosis is the common lesion in surgical series; but in children, MTS is uncommon, and when it does occur, it exists frequently as dual pathology. The most common lesions in pediatric epilepsy surgery candidates are malformations of cortical development, developmental tumors, or encephalomalacia from infarction, hypoxia, trauma, or infection. Careful analysis of the lesion characteristics on brain MRI is sufficiently predictive of pathology in most cases. Histopathological evaluation remains the gold standard for diagnosis of mass lesions. The electroclinical phenotype of epilepsy in adults is largely determined by the anatomical location of the lesion and its connectivity. In children, in addition to the location of the lesion, the age at onset of the lesion and the age at onset of epilepsy have a major impact on the electroclinical phenotype. Children with congenital or early acquired lesions may manifest with generalized features on EEG and seizure semiology. Experience from various centers has demonstrated that a subset of these children benefit from epilepsy surgery despite a generalized epilepsy phenotype. All children with medically refractory epilepsy and a focal lesion should undergo evaluation for potential epilepsy surgery irrespective of the EEG findings and seizure semiology.

Varying seizure semiology according to age

The clinical manifestations of seizures change in a predictable fashion with advancing age. For focal seizures these changes can be summarized into domains similar to those used in developmental models. These include fine motor, communication, and gross motor manifestations. Instead of socialization the fourth domain for seizure semiology concerns synchronization. Focal seizures in the very young tend to be simpler with fewer fine motor manifestations. Auras are uncommon, even in young children with some linguistic skill and it is often difficult to discern alteration of consciousness. Infantile focal seizures can present with spasms or even diffuse tonic seizures. In terms of synchronization, orderly secondary generalization is rarely seen so that primary generalized clonic seizures are rarely recorded in infants. Amongst so-called "generalized" seizures spasms are most often seen in the first year of life. Absence seizures, myoclonic-astatic and generalized tonic-clonic seizures are all usually not seen until after age 2 years. A full description of the clinical details of seizures is probably the most important part of the epilepsy history. A detailed knowledge of seizure semiology can make the history more effective and also in the identification of the correct seizure classification.

Pediatric temporal lobe epilepsy surgery: resection based on etiology and anatomical location

Advances in electrophysiological assessment with improved structural and functional neuroimaging have been very helpful in the use of surgery as a tool for drug-resistant epilepsy. Increasing interest in epilepsy surgery has had a major impact on adult patients; a refined evaluation process and new criteria for drug resistance combined with refined surgical techniques resulted in large surgical series in many centers. Pediatric surgery has lagged behind this evolution, possibly because of the diverse semiology and electrophysiology of pediatric epilepsy obscuring the focal nature of the seizures and frustrating the treatment of catastrophic epileptic syndromes specific to children. Unfortunately, refractory -epilepsy is more -devastating in children than in adults as it interferes with all aspects of neural development. Nevertheless, during the last few decades, the efforts of a small number of centers with encouraging results in pediatric epilepsy surgery have motivated pediatric neurologists to gain interest. Although well behind in the number of patients compared with that of adults, pediatric series are increasing exponentially. While temporal lobe epilepsy is the focus of interest in adults, with almost 70 % of resections in the temporal lobe, the pediatric epilepsy spectrum is different. Resective or functional surgery techniques devoted to resistant extratemporal epilepsy are the major improvements in pediatric epilepsy surgery. Temporal lobe epilepsy in adults has been studied extensively but only recently has begun to receive attention in children. Several aspects of temporal lobe epilepsy in childhood remain unclear or controversial in terms of seizure semiology and its pathology. This is reflected in the surgical treatment. Information on the major contributors to a favorable outcome, such as type or extent of resection, in terms of seizure control and morbidity is not available as in adult temporal lobe epilepsy. This chapter discusses the major discrepancies between adult and pediatric temporal lobe epilepsy and outlines the current concepts in surgical treatment. The resection strategy based on the different substrates at different locations in the temporal lobe causing seizures is emphasized with respect to available literature.

Temporal lobe epilepsy semiology

Epilepsy represents a multifaceted group of disorders divided into two broad categories, partial and generalized, based on the seizure onset zone. The identification of the neuroanatomic site of seizure onset depends on delineation of seizure semiology by a careful history together with video-EEG, and a variety of neuroimaging technologies such as MRI, fMRI, FDG-PET, MEG, or invasive intracranial EEG recording. Temporal lobe epilepsy (TLE) is the commonest form of focal epilepsy and represents almost 2/3 of cases of intractable epilepsy managed surgically. A history of febrile seizures (especially complex febrile seizures) is common in TLE and is frequently associated with mesial temporal sclerosis (the commonest form of TLE). Seizure auras occur in many TLE patients and often exhibit features that are relatively specific for TLE but few are of lateralizing value. Automatisms, however, often have lateralizing significance. Careful study of seizure semiology remains invaluable in addressing the search for the seizure onset zone.

Temporal lobe epilepsy in children

The temporal lobe is a common focus for epilepsy. Temporal lobe epilepsy in infants and children differs from the relatively homogeneous syndrome seen in adults in several important clinical and pathological ways. Seizure semiology varies by age, and the ictal EEG pattern may be less clear cut than what is seen in adults. Additionally, the occurrence of intractable seizures in the developing brain may impact neurocognitive function remote from the temporal area. While many children will respond favorably to medical therapy, those with focal imaging abnormalities including cortical dysplasia, hippocampal sclerosis, or low-grade tumors are likely to be intractable. Expedient workup and surgical intervention in these medically intractable cases are needed to maximize long-term developmental outcome.

Mesial temporal lobe epilepsy with hippocampal sclerosis: study of 42 children

PURPOSE

We present the electroclinical features, treatment, and evolution of patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS).

MATERIAL AND METHODS

We analyzed the charts of forty-two patients who met the diagnostic criteria of MTLE-HS. The mean follow-up after seizure onset was 10.5 years.

RESULTS

According to age, we defined three groups. The first group included nine patients that started with seizures before 2 years of age. Motor seizures were the hallmark clinical manifestation. All patients of this group also presented with motor arrest and oro-alimentary automatisms. In three of them, the interictal EEG recordings showed bilateral paroxysms predominantly in anterior regions, in addition to focal abnormalities, and two had an apparently generalized ictal pattern. The second group included 17 patients that started with seizures between 2 and 10 years of age. In this group the automatisms were also oroalimentary, but more complex and the patients had less motor manifestations. The interictal EEG recordings showed temporal abnormalities. The ictal EEG recordings showed lateralized abnormalities with a maximum in the temporal electrodes. The third group included 16 patients that started with seizures between 10 and 16 years of age. The most common clinical manifestation was abdominal aura followed by oroalimentary, gestural, and verbal automatisms. The interictal and ictal EEG recordings showed well-localized abnormalities in temporal lobes. Thirty-eight patients underwent surgical treatment. Thirty-five patients are seizure free.

CONCLUSION

MTLE-HS represents a well-defined and distinct symptomatic epileptic syndrome. Surgical treatment was successful in most patients.

Approach to pediatric epilepsy surgery: State of the art, Part I: General principles and presurgical workup

In 1990, the National Institute of Health adopted epilepsy surgery in children as an option when medications fail. In the past few years several concepts have become increasingly recognized as key to a successful approach to epilepsy surgery in children. These include the concepts of neuronal plasticity, the epileptogenic lesion, the ictal onset, symptomatogenic, irritative, and epileptogenic zones. In addition, several techniques have increasingly been utilized to delineate the above areas in an attempt to determine, in each patient, the epileptogenic zone, defined as the zone the resection of which leads to seizure freedom. When seizure semiology (which defines the symptomatogenic zone), ictal EEG (which identifies the ictal onset zone), and structural imaging (which identifies the epileptogenic lesion) can be reconciled to infer the location of the epileptogenic zone, surgery is usually, subsequently, undertaken. When these diagnostic modalities are discordant, not definitive, or when the epileptogenic zone is close to eloquent cortex, invasive EEG, complemented by other imaging techniques may be needed. These include magnetoencephalography, single photon emission tomography, various types of positron emission tomography, various magnetic resonance imaging modalities (functional, diffusion weighted, other) and other emerging and experimental techniques. While MRI, video-EEG, and neuropsychological assessments are well established components of the presurgical evaluation, the use of the new emerging imaging technologies is dictated by the degree of anatomo-electro-clinical correlations, and, awaiting multicentric studies and more detailed guidelines, remains center-dependent.

Successful radiofrequency ablation of the cerebral cortex in pigs using the venous system: possible implications for treating CNS disorders

BACKGROUND

When pharmacotherapy for epilepsy fails, surgical options, although efficacious, are highly invasive. We explored whether ablation of the cerebral cortex can be performed utilizing the cerebral venous system.

METHODS

Mapping and radiofrequency ablation was performed via the venous system in two pigs.

RESULTS

Eight targeted sites were successfully accessed and four targeted sites successfully ablated via the central cerebral venous network.

CONCLUSION

Electrophysiological mapping and radiofrequency ablation of the cerebral cortex can be performed via the cerebral veins.

Mesial temporal sclerosis in children

Mesial temporal sclerosis is the most frequent cause of drug-resistant temporal lobe epilepsy but has a satisfactory response to surgery, and is considered infrequent in children. OBJECTIVE: To evaluate the clinical, electrographic and radiological spectrum of the disease in children. METHOD: Retrospective study by review of charts of 44 children with a diagnosis of mesial temporal sclerosis on magnetic resonance imaging, attended at the "Hospital das Clínicas" of the University of São Paulo Faculty of Medicine. RESULTS: Febrile seizure was identified in the history of 54% of the patients. Injuries at the left side predominated in patients with schooling difficulties (p=0.049), in those with the first seizures between six months and five years (p=0.021) and in those with complex febrile seizure (p=0.032). Thirteen patients were submitted to surgery and of these, eight remained without seizures. CONCLUSION: Febrile seizure may be related in a more direct way to the presence of left-side mesial temporal sclerosis.

Distribution of regional gray matter abnormalities in a pediatric population with temporal lobe epilepsy and correlation with neuropsychological performance

OBJECTIVE

The goals of the work described here were to determine if hippocampal and extrahippocampal atrophy in children with temporal lobe epilepsy (TLE) follows a pattern similar to that in adult patients, and to assess the clinical and neuropsychological relevance of regional brain atrophy in pediatric TLE.

METHODS

Children with symptomatic TLE (n=14: 9 with mesial TLE due to hippocampal atrophy and 5 with TLE due to neocortical lesions), healthy children (n=14), and 9 adults with mesial temporal lobe epilepsy (MTLE) were compared using voxel-based morphometry (VBM) of brain magnetic resonance imaging (MRI). The children underwent a comprehensive neuropsychological battery.

RESULTS

Children with MTLE with unilateral hippocampal atrophy (n=9) exhibited a significant reduction in gray matter in the hippocampus ipsilateral to the seizure origin and significant atrophy in the ipsilateral cingulate gyrus and contralateral middle frontal lobe. Children with TLE (n=14) exhibited a significant reduction in the gray matter of the ipsilateral hippocampus and parahippocampal gyrus. There was a correlation between gray matter volume in children with TLE and scores on several neuropsychological tests. Atrophy in pediatric patients with MTLE was less extensive than that in adults, and involved the hippocampi and the frontal cortex.

CONCLUSIONS

Similar to adult MTLE, pediatric MTLE is associated with hippocampal and extrahippocampal cell loss. However, children display less intense quantifiable gray matter atrophy, which affects predominantly frontal lobe areas. There was a significant association between volume of gray matter in medial temporal and frontal regions and scores on neuropsychological tests. In childhood, TLE and the concomitant cognitive/behavior disturbances are the result of a damaged neural network.

Age-Dependent Seizure Semiology in Temporal Lobe Epilepsy

OBJECTIVE

To examine the effects of age on different aspects of temporal lobe seizure semiology.

METHODS

We performed a video analysis of 605 archived seizures from 155 consecutive patients (age 10 months to 49 years) selected by seizure freedom after temporal lobectomy. Eighty patients had hippocampal sclerosis (HS). Beside semiological seizure classification, we assessed age dependency of several axes of seizure semiology: (1) aura, (2) number of different lateralizing signs, occurrence of ictal (3) emotional signs, (4) autonomic symptoms, (5) automatisms, and (6) secondary generalization as well as (7) the ratio of motor seizure components.

RESULTS

From the 155 patients, 117 reported aura, 39 had ictal emotional signs, 51 had autonomic symptoms, 130 presented automatisms, while 18 patients showed secondary generalization at least once during their seizures. Altogether 369 (median: 2/patient) different lateralizing signs were recorded. Frequency of HS (p < 0.001), ictal automatisms (p < 0.001), secondary generalization (p = 0.014), number of different lateralizing signs (p < 0.001) increased while the ratio of motor seizure component (p = 0.007) decreased by age. Auras, emotional symptoms, and autonomic signs occurred independently of patients' ages. Hippocampal sclerosis adjusted linear models revealed that the frequency of automatisms and secondarily generalized seizures as well as the number of different lateralizing signs are HS-independent significant variables.

CONCLUSION

Our findings support that brain maturation significantly influences the evolution of some important aspects (motor seizures, lateralizing signs) of temporal lobe seizure semiology. Conversely, other aspects (aura, emotional, and autonomic signs) are independent of the maturation process. This is the first report investigating age dependency of epileptic seizure semiology comparing all age groups.

Temporal lobe surgery for intractable epilepsy in children: an analysis of outcomes in 126 children

OBJECTIVE

Temporal lobectomy is a well-established neurosurgical procedure for temporal lobe epilepsy. In this study, we conducted a retrospective review of children with drug-resistant temporal lobe epilepsy to evaluate seizure outcome after temporal lobe surgery.

METHODS

We reviewed the medical records of 126 children who had surgery for temporal lobe epilepsy at The Hospital for Sick Children between 1983 and 2003. The records were examined for preoperative and intraoperative factors that could predict patient outcome after surgery.

RESULTS

The mean age at seizure onset was 5.9 years. The mean seizure duration before surgery was 5.6 years. All patients had preoperative computed tomographic scans, magnetic resonance imaging scans, or both. The mean age at the time of surgery was 13.5 years. Sixty-two patients underwent left temporal resections and 64 patients underwent right temporal resections. The histopathology of the temporal resections revealed low-grade brain tumors in 65 children (52%) and cavernous malformations in four children. Ganglioglioma and astrocytoma were the most common tumors encountered. Mesial temporal sclerosis was found in 16 patients (13%), astrogliosis in 15 patients (12%), and cortical dysplasia in eight patients (7%). Postoperative follow-up of at least 2 years was available for 106 patients and ranged up to 13.0 years. Seventy-four percent of patients had an Engel Class I or II outcome. Patients with temporal lobe lesions had better outcomes compared with those without lesions (P < 0.05). Patients without a history of secondary generalization of seizures also had a better outcome when compared with those with secondary generalization. Complications in the form of contralateral homonymous hemianopsia, dysphasia, and infection were found in 5% of patients. Twelve patients had a second temporal lobe procedure for intractable recurrent seizures. After a second procedure, seven patients returned to a seizure-free state.

CONCLUSION

Temporal lobe resections for epilepsy in children are effective and safe procedures, with a favorable impact on seizure control. Repeat temporal resections for recurrent seizures may also be effective in restoring a seizure-free outcome to children.

Interictal EEG in Temporal Lobe Epilepsy in Childhood

The authors clarified the value of interictal discharges and verified which extratemporal regions may also show epileptiform activity in temporal lobe epilepsy (TLE) in childhood. Thirty consecutive patients aged 3 to 18 years (mean age = 12.16 years; 16 male) with TLE associated with hippocampal atrophy were studied. Each patient had 1 to 15 interictal EEG recordings (mean: 5.6; total = 192 EEGs). Video-EEG monitoring was performed in 20 patients. All patients had MRI. The findings were compared with a control group of 53 consecutive TLE adult outpatients with hippocampal atrophy. Each adult patient underwent 3 to 21 routine EEGs (mean: 10.67; total = 566). Interictal EEGs of children with TLE showed extratemporal epileptiform discharges more frequently than EEGs of adults with TLE. Frontal, parietal, and occipital discharges were more frequently seen in children (P < 0.05). These results suggest a close interaction between temporal and other cerebral regions in children with epilepsy and provide further evidence of the existence of neural networks.

Temporal Lobe Epilepsy in Children: Electroclinical Study of 77 Cases

PURPOSE

Temporal lobe epilepsy (TLE) is probably more difficult to recognize in children than in adults. In fact, ictal symptoms in children are less stereotyped and less obvious, and the neuropathological substrate is more heterogeneous than in adults. The aim of this study is to examine the relationships between etiology, age at onset and electroclinical findings in 77 children with TLE, 32 of whom were surgically treated.

METHODS

Electroclinical study including video-EEG recording of seizures in 77 children with TLE. The investigation focused on the first five initial ictal symptoms.

RESULTS

Age at onset was less than 3 years in 39 cases, between 3 and 6 years in 17 cases and older than 6 years in 21 cases. Auras also occurred in younger children but were more common after the age of 6 years. A peculiar initial ictal semiology consisted in staring with arrest, lip cyanosis, and very slight oral automatisms. In some cases, EEG recordings documented seizures starting independently on both temporal lobes. Based on electroclinical and neuroradiological features, we recognized three subgroups: symptomatic TLE due to cortical malformations or nonevolutive tumors, TLE with mesial temporal sclerosis, and cryptogenic TLE.

CONCLUSIONS

A correct electroclinical and neuroradiological approach allows in several cases early recognition of TLE even when onset is earlier than the age of 6 years. A correct definition of the localization relies primarily on video-EEG recording of the seizures, possibly repeated during follow up in cases lacking obvious neuroradiological correlation.

Relative frequency, clinical, neuroimaging, and postsurgical features of pediatric temporal lobe epilepsy

We describe the relative frequency, clinical features, neuroimaging and pathological results, and outcome after pharmacological or surgical intervention for a series of pediatric patients with temporal lobe epilepsy (TLE) from an epilepsy center in Brazil. The medical records of children younger than 12 years with features strongly suggestive of TLE were reviewed from January 1999 to June 1999. Selected children were evaluated regarding clinical, EEG, and magnetic resonance imaging (MRI) investigation and divided into three groups according to MRI: group 1 (G1, N = 9), patients with hippocampal atrophy; group 2 (G2, N = 10), patients with normal MRI, and group 3 (G3, N = 12), patients with other specific temporal lesions. A review of 1732 records of children with epilepsy revealed 31 cases with TLE (relative frequency of 1.79%). However, when the investigation was narrowed to cases with intractable seizures that needed video-EEG monitoring (N = 68) or epilepsy surgery (N = 32), the relative frequency of TLE increased to 19.11 (13/68) and 31.25% (10/32), respectively. At the beginning of the study, 25 of 31 patients had a high seizure frequency (80.6%), which declined to 11 of 31 (35.5%) at the conclusion of the study, as a consequence of pharmacological and/or surgical therapy. This improvement in seizure control was significant in G1 (P < 0.05) and G3 (P < 0.01) mainly due to good postsurgical outcome, and was not significant in G2 (P > 0.1, McNemar's test). These results indicate that the relative frequency of TLE in children was low, but increased considerably among cases with pharmacoresistant seizures. Patients with specific lesions were likely to undergo surgery, with good postoperative outcomes.

Interictal electroencephalographic findings in children and adults with temporal lobe tumors

OBJECTIVE

To characterize clinical and interictal electroencephalographic aspects of children and adults with temporal lobe epilepsy (TLE) due to tumoral lesions.

METHOD

We performed a retrospective analysis of the clinical and interictal electroencephalographic aspects of 16 children (64 exams) and 12 adults (78 exams) with lesions in the temporal lobe.

RESULTS

The most frequent etiologies were gangliogliomas, DNETs, followed by astrocytomas. Auras occurred in both groups, the most common being epigastric sensation. Other findings such as myoclonias, behavioral arrest and vomiting were more frequent in children. Temporal epileptiform and nonepileptiform activities, mostly unilateral, were found in both groups. Extratemporal epileptiform activities (frontal, parietal, central, occipital and generalized) were also found equally in both groups.

CONCLUSION

Our data show that children and adults with TLE due to expansive lesions present with similar EEG findings.

Treatment options and paradigms in childhood temporal lobe epilepsy

Temporal lobe epilepsy in adults is a relatively homogenous syndrome with hippocampal sclerosis being its most common pathologic substrate. In the pediatric age group, low-grade neoplasms and cortical dysplasia are much more common than hippocampal sclerosis. Pediatric temporal lobe epilepsy has distinct semiologic, electrophysiologic and imaging characteristics as compared with its adult counterpart. The various treatment options for pediatric temporal lobe epilepsy include antiepileptic drugs, resective surgery, vagal nerve stimulation and the ketogenic diet. In spite of the multiple antiepileptic drugs currently available, 5-10% of all newly diagnosed cases will remain intractable to medical therapy and should be referred for presurgical evaluation. Resective surgery offers the best chance of seizure freedom in carefully selected patients. Future areas of research include new drug development, better imaging and localization techniques, and brain stimulation.

Hippocampal Sclerosis in Children with Lesional Epilepsy Is Influenced by Age at Seizure Onset

PURPOSE

Hippocampal sclerosis (HS) is the most common lesion underlying drug-resistant temporal lobe epilepsy. Whether HS is a developmental or acquired pathology remains unclear. Whereas HS has been causally linked to prolonged febrile convulsions in childhood, evidence also exists that it may coexist with extrahippocampal abnormalities, the concept of "dual pathology." The aims of this study were to address whether hippocampal abnormality consistent with HS (a) occurs in children with lesional extrahippocampal epilepsy, (b) is more commonly seen in association with developmental rather than acquired extrahippocampal pathologies, and (c) whether any effect of age at seizure onset is found on the occurrence of HS in lesional extrahippocampal epilepsy.

METHODS

Clinical and histopathologic data of patients having resective surgery for extrahippocampal epilepsy that included the hippocampus were investigated.

RESULTS

Twenty-nine children were retrospectively included in this study, and 21 (72%) of 29 were found to have a hippocampal abnormality consistent with HS. No relation was noted between developmental or acquired extrahippocampal pathologies and the presence of hippocampal abnormality. Children with normal hippocampi on visual histologic assessment had a significantly younger age at seizure onset (p < 0.001). Duration of epilepsy was not correlated with the presence of hippocampal abnormality.

CONCLUSIONS

Hippocampal abnormalities are seen in similar proportions with both acquired and developmental extra-hippocampal pathologies, suggesting that these abnormalities are the result of seizures from the focus that is remote from the hippocampus. In addition, children who have their initial seizure at an early age are less likely to develop seizure-induced hippocampal injury.

Abnormal behavior in children with temporal lobe epilepsy and ganglioglioma

Temporal lobe epilepsy in childhood is characterized by great clinical, electroencephalographic, and etiological diversity. The prognosis after temporal lobe epilepsy surgery in childhood is usually good, with most patients achieving complete seizure control. However, in some children behavior deteriorates postoperatively. We report two girls (2 and 6 years of age) with refractory seizures due to temporal lobe ganglioglioma. They exhibited aggression and hyperactivity since the beginning of their epilepsy. In both patients, behavioral disturbances worsened postoperatively, despite complete seizure control. Patients and parents should be advised about possible behavioral disturbances after epilepsy surgery, especially in the presence of a temporal lobe developmental tumor, even when seizure control is achieved postoperatively.

Analysis of different types of resection for pediatric patients with temporal lobe epilepsy

OBJECTIVE

Resection strategies for the treatment of temporal lobe epilepsy (TLE) are a matter of discussion. Few data on the significance of resection type are available for pediatric patients with TLE.

METHODS

Data for a series of 89 children who were surgically treated for TLE were analyzed. A first cohort of patients were mainly surgically treated with anterior temporal lobectomies. For a second cohort, resections were preoperatively "tailored" to the lesion and presumed epileptogenic area.

RESULTS

The follow-up period was 46 months (range, 14-118 mo). Seventy-seven patients (87%) attained satisfactory seizure control (82% Engel Class I and 5% Class II). For 12 patients (13%), seizure control was unsatisfactory (8% Class III and 5% Class IV). Anterior temporal lobectomies resulted in 94% satisfactory seizure control (33 patients), whereas the success rates were only 74% (20 patients) for amygdalohippocampectomy (AH) (P = 0.023) and 77% (13 patients) for lesionectomy plus hippocampectomy (not significant). All patients who underwent purely lateral temporal lesionectomies became seizure-free (14 patients). Logistic regression revealed the factors of AH (P = 0.021) and left-side surgery (P = 0.017) as significant predictors of unsatisfactory seizure control. Satisfactory seizure control was not dependent on the histopathological diagnoses. There was a low rate of verbal memory deterioration after left-side operations. Neuropsychological deterioration was rare after right temporal resections. Attentional and contralateral functions improved after surgery.

CONCLUSION

Surgery for the treatment of juvenile TLE is successful and safe, but the resection type may influence outcomes. Results after AHs were disappointing, probably because of difficulties in precise localization of the epileptogenic focus among children. Neuropsychological results demonstrated minimal rates of deterioration and significant improvements in contralateral functions. Surgical treatment of juvenile TLE should be encouraged, but the use of especially left AH should possibly be restricted.

Clinical, electroencephalographic, and behavioral features of temporal lobe epilepsy in childhood

This study describes the clinical, electroencephalographic, and behavioral features of 36 children with temporal lobe epilepsy. Patients were divided into two groups: group A, with 6 patients (< 6 years), and group B, with 30 patients (6-18 years). Statistical analysis was performed considering the significance level of .05. Regarding the clinical features of the focal seizures, motor components were more frequently seen in children younger than 6 years of age (P < .01), whereas automatisms were more frequently seen in patients older than 6 years of age (P < .05). Associated myoclonic seizures were more frequent in the younger age group (P < .01). Behavioral disorders such as hyperactivity and aggressiveness and speech delay were more common in the younger age group (P < .05). Temporal lobe epilepsy in children younger than 6 years of age is more frequently associated with motor components, myoclonic seizures, behavioral disorders, and speech delay. Conversely, temporal lobe epilepsy in older patients has frequent automatisms.

Extratemporal resection for childhood epilepsy

There have been relatively few studies reporting the safety, efficacy, and outcome in children undergoing extratemporal resection for epilepsy. We reviewed the pediatric cases of extratemporal resection for intractable epilepsy performed by the Comprehensive Epilepsy Program at the University of Alberta Hospitals between 1988-1998. Thirty-five patients were studied, 14 male and 21 female. The age at operation ranged from 6 months to 16 years. The operations included frontal excisions (12), parietal (8), occipital (4), hemispherectomies or multilobar resections (10), and one removal of a hypothalamic hamartoma. The pathology at surgery included patients with focal cortical dysplasia (8), brain tumors (6), neurocutaneous syndrome (7), Rasmussen's encephalitis (2), porencephalic cysts (4), hypothalamic hamartoma (1), and nonspecific gliosis (6). Twenty-four of 35 patients (68.5%) had an Engel Class I outcome after surgery and an additional six patients (11%) had a significant decrease in seizure frequency (Engel Class III). Complications were observed in two patients (5%) and there were no deaths. Extratemporal resection is a safe and effective treatment for children with intractable epilepsy. Overall, 68% of patients were seizure-free after surgery, although outcome may be dependent on site and pathology. A wide range of developmental pathology was observed including focal cortical dysplasia, brain tumors, and lesions with neurocutaneous syndromes. Many families reported improvement in behavior and psychosocial function after surgery.

Seizure Semiology in the Elderly: A Video Analysis

PURPOSE

To describe the seizure semiology of patients older than 60 years and to compare it with that of a control group of younger adults matched according to the epilepsy diagnosis.

METHODS

Available videotapes of all patients aged 60 years and older who underwent long-term video-EEG evaluation at the Cleveland Clinic Foundation (CCF) between January 1994 and March 2002 were analyzed by two observers blinded to the clinical data. A younger adult control group was matched according to the epilepsy diagnosis, and their seizures also were analyzed.

RESULTS

Fifty-four (3.3%) of the 1,633 patients were 60 years or older at the time of admission. For 21 of them, at least one epileptic seizure was recorded. Nineteen patients had focal epilepsy (nine temporal lobe, two frontal lobe, two parietal lobe, eight nonlocalized), and two patients had generalized epilepsy. Seventy-three seizures of the elderly patients and 85 seizures of the 21 control patients were analyzed. In nine elderly patients and 14 control patients, at least one of their seizures started with an aura. Eleven elderly patients and 19 control patients lost responsiveness during their seizures. Approximately two thirds of the patients in both groups had automatisms during the seizures. Both focal and generalized motor seizures (e.g., clonic or tonic seizures) were seen less frequently in the elderly.

CONCLUSIONS

Only a small percentage of the patients admitted to a tertiary epilepsy referral center for long-term video-EEG monitoring are older than 60 years. All seizure types observed in the elderly also were seen in the younger control group, and vice versa. Simple motor seizures were seen less frequently in the elderly.

Cirurgia para epilepsia na infância: avaliação neuropsicológica e de qualidade de vida

PURPOSE

To perform neuropsychological and quality of life assessments before and after epilepsy surgery in children; to correlate these parameters with clinical findings.

METHOD

Nine children with refractory epilepsy were evaluated before and six months after the surgical treatment with a comprehensive neuropsychological battery and quality of life questionnaire. Children had variable etiologies and surgical procedures.

RESULTS

IQ changes did not occur; two children with temporal lobe epilepsy due to tumor had important behavior impairment after surgery despite complete seizure control; best neuropsychological improvement was seen in the child who had Rasmussen's encephalitis and underwent hemispherectomy. Social aspects, drug side effects, seizure perception and the overall level of quality of life improved after surgery.

CONCLUSION

Quality of life improvement was clearly correlated with seizure control; nevertheless, neuropsychological improvement depended on several factors, such as etiology, type of epilepsy and surgery.

Therapeutics in pediatric epilepsy, Part 2: Epilepsy surgery and vagus nerve stimulation

When antiepileptic drugs fail to relieve seizures adequately in children and adolescents, more invasive therapies such as epilepsy surgery and an implanted device to stimulate the vagus nerve should be considered. Temporal lobectomy is an effective treatment of complex partial and secondarily generalized tonic-clonic seizures arising in the mesial structures or lateral temporal neocortex. Excellent outcomes (seizure free or rare, nondisabling seizures) are achieved in at least 70% of children. The most common adverse effect is a superior quadrant field cut that is usually asymptomatic. Transient and more long-lasting language difficulties have been reported when the surgery involves the dominant temporal lobe. The excellent outcome rate for extratemporal surgery ranges from approximately 20% to 80%, with better results seen in patients with an identifiable lesion. Potential morbidity is related to the region of resected neocortex. Corpus callosotomy is an excellent procedure for palliation but is not a cure for seizures that cause falls, with substantial improvement seen in more than 80% of patients. Potential adverse effects include more intense focal seizures and dysphasia, depending on the developmental level of the individual. Hemispherectomy provides seizure relief in 60% to 80% of patients with hemispherical pathologies such as Sturge-Weber or Rasmussen syndromes. Operative mortality has been reported in the range of 0% to 6%; other morbidities include infection and hydrocephalus. Stimulation of the vagus nerve has reduced partial seizures by 50% or more in approximately one third of patients. No adverse cognitive or systemic effects are associated with use of the implanted vagus nerve stimulator.

A detailed analysis of symptomatic posterior cortex seizure semiology in children younger than seven years

PURPOSE

To analyze the semiology of seizure onset and evolution in young children with posterior cortex epilepsy (PCE), compare this with adult reports, and assess age-related differences.

METHODS

We videotaped and analyzed 110 seizures from 18 patients with PCE, aged 3-81 months. All had a good prognosis after posterior epileptogenic zone removal. Ictal events were categorized by behavioral, consciousness, autonomic, and sensory features, as well as motor patterns, which included myoclonic, tonic, clonic, unclassified motor seizures, and epileptic spasm. A time-scaled data sheet was developed to record each epileptic event as onset, very early, early, or late manifestation.

RESULTS

Patients had a high seizure frequency with < or =100 attacks/day; one third of them showed a cluster tendency. The mean duration of seizures was 67 s. The most common seizure components were motor manifestations (with myoclonic and tonic seizures), but psychomotor (automotor), hypomotor attacks, and isolated auras also were frequently observed. Clinical seizure spread was frequent; auras and visual sensory signs were difficult to record in this age. Typical phenomena during seizures included behavioral changes, ictal vocalization, smile, flush, head nod, oculomotor features, and late-appearing oral automatisms, whereas hypermotor and secondarily generalized tonic-clonic seizures were not seen.

CONCLUSIONS

Our results suggest that PCE in infants and young children is very heterogeneous but shows important age-related features. Compared with adults, children with PCE have shorter but more frequent seizures; they rarely report aura or visual sensory signs, only sporadically develop hypermotor and secondarily generalized tonic-clonic seizures, whereas ictal smile, flush, head nod, and behavioral change are typical features at this age. Because of frequent subtle ictal phenomena, long-term video-EEG monitoring is a useful diagnostic tool with infants and young children with PCE.

Epilepsy surgery. Presurgical evaluation

The presurgical evaluation should result in a clear understanding of whether surgery can be undertaken and its associated risks and potential for benefit. The results of surgery are best when there is congruence in the seizure semiology, the irritative zone on interictal EEG, and the ictal onset zone with the epileptogenic lesion as defined on MRI and PET, and when there is a clear understanding of the ictal onset zone's relationship to eloquent cortex as defined by neuropsychologic evaluation, the intracarotid amobarbital test, and cortical functional mapping.

When should temporal-lobe epilepsy be treated surgically?

Our current knowledge of mesial-temporal-lobe epilepsy (MTLE) is extensive, yet still insufficient to draw final conclusions on the optimal approach to its therapy. MTLE has been well characterised and can usually be identified with noninvasive studies including scalp electroencephalography (EEG) and video monitoring with ictal recording, magnetic resonance imaging, single-photon-emission computed tomography, positron emission tomography, neuropsychological assessment, and historical and clinical data. Sometimes, invasive EEG is needed to confirm mesial-temporal-lobe seizure onset, which, combined with the underlying pathological abnormality (the substrate) of mesial temporal sclerosis (hippocampal neuronal loss and gliosis), defines MTLE. This disorder is the most common refractory partial epilepsy, and also the one most often treated surgically, because medical treatment fails in 75% of cases, and surgical treatment succeeds in a similar percentage. Despite the recent publication of the first randomised trial of surgical treatment for MTLE, questions remain about the neurological consequences of both medical and surgical treatment, the ultimate gains in quality of life parameters, and the precise predictors of success. Long-term follow-up and analyses of multiple factors in large groups of contemporary patient populations will be necessary to fully answer the question, "is temporal lobe epilepsy a surgical disease?" Right now it should be considered one in most cases.

Hypomotor seizures in infants and children

PURPOSE

Hypomotor seizures (characterized by diminished behavioral activity with indeterminate level of consciousness) have been identified as an important seizure type in infants. Our goal was to investigate further the clinical and EEG features of hypomotor seizures.

METHODS

We retrospectively reviewed 110 hypomotor seizures from 34 patients recorded with video-EEG.

RESULTS

Twenty-seven (79%) patients were younger than 48 months, and seven (21%) were aged 4 to 15 years. Seventy-one (64%) seizures had regional or lateralized EEG onset, arising predominantly from temporal or parietal lobe regions. The other 39 (35%) seizures had generalized onset, usually with abrupt onset of diffuse rhythmic high-amplitude theta activity or diffuse electrodecrement and only rarely (two patients) with slow spike-wave complexes or 3-Hz spike-wave complexes. Hypomotor seizures with generalized EEG onset were significantly shorter than those with regional or lateralized onset (p = 0.01, GEE model). Unsustained head or eye movements and subtle mouth automatisms were commonly seen in hypomotor seizures with either focal or generalized onset. Seventeen percent of hypomotor seizures with focal onset evolved to include version of head and eyes or jerking of one arm, whereas 2% of generalized hypomotor seizures evolved to a cluster of spasms.

CONCLUSIONS

Hypomotor seizures may be either focal or generalized. Regional EEG onsets were most often temporal or parietal, suggesting that focal hypomotor seizures may be a bland form of "complex partial" seizures with no or minimal automatisms, seen predominantly in infants. Generalized hypomotor seizures were rarely associated with an ictal pattern of generalized spike-wave complexes, suggesting a different mechanism from absence seizures seen later in life.

Adolescent seizures and epilepsy syndromes

Specific epilepsy syndromes begin during adolescence and create a significant neurologic burden. Knowledge of these syndromes has important treatment and prognostic implications, which usually extend into adulthood. Little is known about the effect of menarche on seizures, even though a relationship of seizures to the menstrual cycle has been observed for many years. In general, puberty is not thought to influence seizure frequency. However, estrogen is thought to activate epileptiform activity; testosterone may decrease seizure activity; and progesterone decreases epileptiform discharges. These effects are mediated by effecting gammaaminobutyric acid (GABA) transmission. Idiopathic generalized epilepsies are the most frequent group with adolescent onset. These are probably polygenic in origin and represent a biologic continuum. Juvenile myoclonic epilepsy (JME) is the most common form. This contrasts with a variety of progressive myoclonic epilepsies that also are first seen in adolescence and have a genetic origin and specific treatments. Finally, although temporal lobe epilepsy associated with hippocampal sclerosis may have its origin in childhood, often the child does not come to surgical evaluation until adolescence or young adulthood. The characteristic clinical history, seizure semiology, and magnetic resonance imaging findings have allowed a discrete epilepsy syndrome to be established. Applying these same criteria to children and adolescents reveals that hippocampal sclerosis is the most common lesion responsible for their intractable temporal lobe epilepsy. Hippocampal sclerosis is probably underdiagnosed in children. The safety and efficacy of epilepsy surgery in the age group is excellent. Knowledge of the epilepsy syndromes that remit before adolescence, may persist into adolescence, or begin in adolescence is central to the treatment of this age group.

Epilepsy surgery in childhood

Epilepsy surgery in childhood can now be more readily considered as a result of enhanced presurgical investigative techniques and safer neurosurgical practice. As in adults, surgery available may be resective (focal resection or hemispherectomy) or functional. The most common procedures are temporal lobectomy and hemispherectomy, with malformative lesions and developmental tumours the next common pathology. The timing of surgery requires careful consideration, and the definition of drug resistance given specific thought in the young child. Presurgical evaluation should be noninvasive where possible, and should include optimised MRI, including 3D data set and video EEG telemetry to document seizures. Detection of temporal lobe abnormalities in temporal lobe epilepsy with MR may be enhanced using quantitative and semiquantitative techniques. Ictal and interictal SPECT may be useful in providing information about the seizure onset zone, if reviewed in conjunction with MR data and video-EEG. Interictal PET is more likely to demonstrate abnormalities relating to structural defects, but may be particularly useful in infants where incomplete myelination may restrict structural information provided by MRI. Neuropsychology testing plays a major role by the determination of verbal and nonverbal function in older children, and in the determination of cerebral dominance. Functional MRI for determination of language or motor cortex may enhance such evaluation, although it is limited to older unsedated children at present. Although the aims of the presurgical evaluation remain similar to adult practice, the range of children presenting is wide, and the aims and likely outcome of surgery require careful evaluation with the family. This aside, the benefits of seizure elimination or reduction in drug-resistant focal epilepsy prior to adolescence, as well as in certain early catastrophic epilepsies of childhood, remain self apparent.

The effect of age on seizure semiology in childhood temporal lobe epilepsy

PURPOSE

Complex partial seizure is the characteristic seizure type observed in epilepsy arising from temporal lobe structures. The seizure evolution in adult patients is quite stereotyped and well characterized, manifesting initially with an aura, behavioral arrest, and oroalimentary and gestural automatism. A greater variability of semiology including motor features with tonic or myoclonic components, as well as a paucity of automatism, has been reported in young children with temporal lobe epilepsy. The aim of our study was to examine in more detail the effects of age on individual ictal features to be able to determine the critical age when lesional temporal lobe seizure semiology undergoes transition from the pediatric to the more adult-type clinical pattern.

METHODS

We performed a video analysis of 83 seizures from 15 children (aged 11-70 months) selected by post-temporal lobectomy seizure-free outcome, looking specifically at the motor and behavioral (nonmotor) manifestations in relation to age of the children.

RESULTS

All of the children younger than 42 months had seizures with early and marked motor features, which included tonic and myoclonic components and epileptic spasms. Parallel with age, the frequency of these motor components decreased, and in five of 11 children older than 3 years, motor features were totally absent. Analyzed quantitatively, we saw a linear and inverse correlation of the ratio of motor components with age at monitoring.

CONCLUSIONS

These findings support the hypothesis that events in brain maturation significantly affect clinical seizure semiology and may override the more typical localizing features seen in adult-type temporal lobe epilepsy. These findings are important to consider in the early diagnosis of childhood temporal lobe epilepsy.

Semiology of temporal lobe epilepsy in children and adolescents. Value in lateralizing the seizure onset zone [corrected]

PURPOSE

To determine the frequency and lateralizing value of clinical seizure symptoms in children and adolescents with drug-resistant temporal lobe epilepsy (TLE).

METHODS

Patients enrolled had to be <18 years of age and seizure free at follow-up for at least 12 months after epilepsy surgery. Patients were assigned to two age groups, children (age<12 years) and adolescents (age>12 and <18 years). Video-tapes were reviewed blinded to patients' demographic data and results of additional investigations by two independent raters. Clinical signs of known lateralizing significance in adults and additional clinical signs without lateralizing value were assessed.

RESULTS

14 patients (eight boys; 2-18 years) fulfilled the inclusion criteria. Inter-observer agreement was excellent (kappa coefficient: 0.82). Compared with adult series, no differences were found concerning overall occurrence of lateralizing signs and lateralizing accuracy. There were age-related differences, however, concerning the occurrence of individual signs: secondary generalization, complex automatisms and version were less frequent in children than in adolescents.

CONCLUSIONS

Clinical signs of lateralizing value can also be found in children and adolescents, provided that the evaluation protocols used consider developmental aspects.

Temporal lobectomy in early childhood: the need for long-term follow-up

We retrospectively identified 15 children ages 12 years and under with anticonvulsant resistant epilepsy who underwent a temporal lobectomy at Children's Hospital, Boston, between 1978 and 1993. Our aim was to study the long-term seizure outcome. Data pertaining to preoperative evaluation, electroencephalography (EEG), neuroimaging, surgery, seizure outcome, and postoperative complications were reviewed. Only patients followed for more than 12 months were included. The average duration of follow-up was 57 months. At the last visit, 47% (7 of 15) of the children were seizure free or only had auras: another 33% (5 of 15) had > 90% reduction in seizure frequency. Three patients had < 90% seizure reduction. Four cases were initially seizure free but had subsequent recurrence between 11 and 28 months after the epilepsy surgery. Factors associated with a good outcome include exclusively focal EEG discharges or an imaging suggestive of a low-grade tumor; factors associated with a poor outcome include generalized EEG discharges and a normal magnetic resonance image. Temporal lobectomy is useful in the treatment of early childhood drug-resistant partial epilepsy, but long-term follow-up is necessary as late seizure recurrence may occur up to 28 months after surgery.