Recent advances in childhood epilepsy

Surgery of epilepsy associated with focal lesions in childhood

OBJECT

Surgery in children with epilepsy is a new, evolving field. The important practical issues have been to define strategies for choosing the most suitable candidates and the type and optimal timing of epilepsy surgery. This study was undertaken to elucidate these points.

METHODS

To identify the factors that correlated with outcome, the authors analyzed a series of 200 children (aged 1-15 years (mean 8.7 years) who underwent surgery between 1981 and 1996 at the Hôpital Necker-Enfants Malades. In 171 cases (85.5%) the epilepsy was medically refractory and was associated with focal cortical lesions. Surgery consisted of resection of the lesion without specifically attempting to identify and remove the "epileptogenic area. "In the group of children whose seizures were medically refractory, the mean follow-up period was 5.8 years. According to Engel's classification, 71.3% of these children became seizure free (Class 1a,) whereas 82% were in Class I. A multivariate statistical analysis revealed that among all the factors studied, the success of surgery in a patient in whom there was a good clinical/electroencephalogram/imaging correlation depended on the patient's having undergone a minimally traumatic operation, a complete resection of the lesion, and a short preoperative seizure duration. After the surgical control of epilepsy, behavior disorders were more improved (31% of all patients) than cognitive function (25%). The patient age at onset, duration and frequency of seizures, intractability of the disease to therapy, and seizure characteristics were correlated with cognitive, behavioral, and academic performance pre- and postoperatively. Multivariate statistical analysis revealed that cognitive dysfunction correlated highly with the duration of epilepsy prior to surgery, whereas behavioral disorders correlated more with seizure frequency.

CONCLUSIONS

These data must be taken into account when selecting patients for surgical treatment and when deciding the timing of surgery. Early surgical intervention allows for optimum brain development.

Surgery in epilepsy associated with focal lesions in childhood

Surgery in children with epilepsy is a new, evolving field. The important practical issues have been to define strategies for choosing the most suitable candidates, as well as the type and the optimum timing of epilepsy surgery. This study was undertaken to illustrate these points.

To identify the factors that correlated with outcome, the authors analyzed a series of 200 children (aged 1–15 years, mean 8.7 years) who underwent surgery at the Hôpital Necker-Enfants Malades between 1981 and 1996. In 171 cases (85.5%) the epilepsy was medically refractory and was associated with focal cortical lesions. Surgery consisted of resection of the lesion without specifically attempting to identify and remove the "epileptogenic area."

In the group of children whose seizures were medically refractory, the mean follow-up period was 5.8 years. According to Engel's classification, 71.3% of these children became seizure free (Ia), whereas 82% were in Class I. A multivariate statistical analysis revealed that among all the factors studied, the success of surgery in a patient in whom there was a good clinical-electroencephalogram-imaging correlation, depended on the patients' having undergone a minimally traumatic operation, a complete resection of the lesion, and a short preoperative seizure duration.

After the surgical control of epilepsy, behavior disorders were more improved (31% of all patients) than cognitive function (25%). The patient age at onset, duration and frequency of seizures, intractability of the disease to therapy, and seizure characteristics, were correlated with cognitive, behavioral, and academic performance pre- and postoperatively. Multivariate statistical analysis revealed that cognitive dysfunction correlated highly with the duration of epilepsy prior to surgery, whereas behavioral disorders correlated more with seizure frequency.

These data must be taken into account when selecting patients for surgical treatment and when deciding the timing of surgery. Early surgical intervention allows for optimum brain development.

Benign focal epileptiform discharges in children after severe head trauma: prognostic value and clinical course

PURPOSE

To assess the occurrence and prognosis of benign focal epileptiform discharges (BFED) in EEG after severe head trauma (SHT) in children.

METHODS

Between January 1987 and December 1994, 47 of 828 children with anamnestic SHT showed a single or dominant epileptic focus in EEG. Spike wave localization and morphology were either suggestive for BFED (group I, 21 children) or were suspected to be symptomatic (group II, 26 children). We analyzed the course of epilepsy and epileptic discharges in EEG, neuroradiologic findings, neurologic outcome, and school adjustment.

RESULTS

After SHT, spike waves appeared immediately (within 72 h) or delayed (maximum 7 years) and disappeared between ages 3 and 14 years in 14 children of group I and between ages 8 and 23 years in 10 of group II. Children with persistent spike waves in group I were all younger than 14 years; in group II, seven were older than 15 years. Computed tomographic (CT) lesions, ipsilateral to the epileptic focus, were seen in 10 children of group I and 15 of group II. Early seizures occurred in nine children of group I and eight of group II and late-onset seizures in one of group I and nine of group II (p = 0.028). Epilepsy developed in three children of group I and 12 of group II and was drug refractory in six children of group II, all with persistent epileptic foci. Regular schools were attended by 14 (67%) children in group I and 12 (48%) of group II.

CONCLUSIONS

Benign focal epileptiform discharges in posttraumatic EEGs have the same favorable prognosis as in benign focal epilepsy and should be handled as recommended for classic benign focal epilepsy.

Neuroimaging of focal malformations of cortical development

Neuroimaging is playing an increasingly important role in the evaluation of patients with malformations of cerebral cortical development. In this review, the authors address optimal neuroimaging of cortical malformations using x-ray computed tomography, single-photon-emission computed tomography, positron emission tomography, magnetic resonance imaging, and magnetic resonance spectroscopy. Initially, the authors discuss the strengths and weaknesses of the various imaging techniques. This is followed by a discussion of the clinical and neuroimaging characteristics of several different imaging manifestations of focal malformations of cortical development, including polymicrogyria, focal subcortical heterotopia, schizencephaly, focally thickened gyri, focally irregular gyri, hemimegalencephaly, and transmural dysplasia. The authors intend that, after reading this review, the reader will have a better understanding of the optimal neuroimaging techniques for evaluating these malformations and their many neuroimaging appearances.

Prognosis of childhood epilepsy in newly referred patients

The aim of this study was to investigate the prognosis of childhood epilepsy and to analyze prognostic factors in addition to remission rate in a follow-up of newly referred patients. Two hundred eighty-one patients were followed for a mean period of 5.3 years. Overall, 253 patients (90%) achieved 1-year remission. The beginning of a 1-year seizure-free period was achieved in 77.9% by 1 year, in 84% by 2 years and in 88.6% by 3 years after onset of treatment. Early onset of seizures, symptomatic etiology, and neurologic handicap predicted a worse prognosis. In 44 of 253 children with complete suppression of seizures for 1 year, relapses occurred within the follow-up period. In one child with a relapse, remission could not be achieved in the 2nd year thereafter. In conclusion, our study shows a good prognosis for most children with epilepsy, especially in patients with idiopathic epilepsy and late onset of seizures and without neurologic dysfunction. Moreover, our data strongly suggest that the long-term pattern of seizure control is largely established during the first 2 years of treatment.

Neuroimaging in pediatric epilepsy

Neuroimaging techniques have advanced the diagnosis, management, and understanding of the pathophysiology underlying the epilepsies. High-resolution ultrasound is an important and useful technique in the investigation of prematures and neonates with seizures. Computed tomography (CT) scans have a diminishing role in the investigation of patients with epilepsy, but in the absence of magnetic resonance imaging (MRI), CT may detect gross structural pathology. MRI is the technique of choice for investigation of patients with seizure disorders. MRI provides excellent anatomic information and tissue contrast, resulting in high sensitivity. MRI studies should be customized to answer the appropriate clinical question. Functional imaging techniques including single photon emission computed tomography (SPECT), positron emission tomography (PET), magnetic resonance spectroscopy, and functional MRI are becoming increasingly important in the investigation and management of patients with seizures. These techniques permit noninvasive assessment of the epileptic substrate, functional status, ictal activity, blood flow changes, metabolism, and neuroreceptors. Application of these new techniques promises to advance our understanding and treatment of seizures in children.

EEG, PET, SPET and MRI in intractable childhood epilepsies: possible surgical correlations

Magnetic resonance imaging (MRI), single photon emission tomography (SPET), and positron emission tomography (PET) using [18F]fluorodeoxyglucose were used in combination with scalp and scalp-video EEGs in a group of 30 pediatric patients with drug resistant epilepsy (DRE) in order to identify patients who could benefit from neurosurgical approach. Seizures were classified according to the consensus criteria of The International League Against Epilepsy. In three patients infantile spasms (IS) were diagnosed; 13 subjects were affected by different types of generalized seizures, associated with complex partial seizures (CPS) in three. In the other 14 patients partial seizures, either simple (SPS) or complex, were present. A localized abnormality was demonstrated in one patient with IS and in three patients with generalized seizures. Of the group of 14 subjects with CPS, MRI and CT were normal in 7, but SPET or PET indicated focal hypoperfusion or hypometabolism concordant with the localization of the EEG abnormalities. In 5 of the other 7 patients anatomical and functional imaging and EEG findings were concordant for a localized abnormality. It can be concluded that functional imaging combined with scalp EEGs appears to be superior to the use of only CT and MRI for selecting children with epilepsy in whom a surgical approach can be considered, in particular when CPS resistant to therapy are present.