Interobserver agreement of the old and the newly proposed ILAE epilepsy classification in children

Do neurologists around the world agree when diagnosing epilepsy? - Results of an international EpiNet study

OBJECTIVE

Previous studies have shown moderate agreement between physicians when diagnosing epilepsy, but have included small numbers. The EpiNet study group was established to undertake multicentre clinical trials in epilepsy. Before commencing trials, we wanted to determine levels of agreement between physicians from different countries and different health systems when diagnosing epilepsy, specific seizure types and etiologies.

METHODS

30 Case scenarios describing six children and 24 adults with paroxysmal events (21 epileptic seizures, nine non-epileptic attacks) were presented to physicians with an interest in epilepsy. Physicians were asked how likely was a diagnosis of epilepsy; if seizures were generalised or focal; and the likely etiology. For 23 cases, clinical information was presented in Step 1, and investigations in Step 2.

RESULTS

189 Participants from 36 countries completed the 30 cases. Levels of agreement were determined for 154 participants who provided details regarding their clinical experience. There was substantial agreement for diagnosis of epilepsy (kappa=0.61); agreement was fair to moderate for seizure type(s) (kappa=0.40) and etiology (kappa=0.41). For 23 cases with two steps, agreement increased from step 1 to step 2 for diagnosis of epilepsy (kappa 0.56-0.70), seizure type(s) (kappa 0.38-0.52), and etiology (kappa 0.38-0.47). Agreement was better for 53 epileptologists (diagnosis of epilepsy, kappa=0.66) than 56 neurologists with a special interest in epilepsy (kappa=0.58). Levels of agreement differed slightly between physicians practicing in different parts of the world, between child and adult neurologists, and according to one's experience with epilepsy.

CONCLUSION

Although there is substantial agreement when epileptologists diagnose epilepsy, there is less agreement for diagnoses of seizure types and etiology. Further education of physicians regarding semiology of different seizure types is required. Differences in approach to diagnosis, both between physicians and between countries, could impact negatively on clinical trials of anti-epileptic drugs.

Type and etiology of pediatric epilepsy in Jordan. A multi-center study

OBJECTIVE

To study types and etiologies of epilepsy in Jordanian pediatric epileptic patients maintained on antiepileptic drugs using customized classification scheme of International League Against Epilepsy (ILAE) (2010) report.

METHODS

This is a cross-sectional, multi-centre study on pediatric epileptic patients on antiepileptic drugs, who were managed in the pediatric neurology clinics at 6 teaching public hospitals in Jordan.

RESULTS

Out of the 663 patients included in the study, (90.2%) had one seizure type, (53%) of this type were focal seizures followed by generalized seizures (41.5%) and spasms (5.5%). Distinctive constellations were found in 11/663 (1.7%) patients. Benign epilepsies with centrotemporal spikes were the most common electro clinical syndromes 60/221 (27.1%). Epilepsies attributed to structural-metabolic causes were documented in 278/663 (41.9%) patients, unknown causes 268/663(40.4%) and genetic causes in 117/663(17.7%). Most common causes of structural-metabolic group were due to perinatal insults (32%) and most common causes of the genetic group were the presumed genetic electro clinical syndromes (93.1%).

CONCLUSION

Our study is on pediatric epilepsy, using customized classification scheme from the ILAE 2010 report which showed interesting results about type and etiology of epileptic seizures from developing country with potential impact on the international level.

Comparison of ILAE 2010 and semiological seizure classification in children with epilepsy

OBJECTIVE

The aim of this study was to compare both ILAE 2010 and semiological seizure classification (SSC) in terms of their applicability and utility and to predict epileptogenic zone in children with epilepsy.

METHODS

Both ILAE 2010 classification and SSC which is a part of five dimensional classification were applied for a total 138 children by dividing into younger (≤6y/o) and older (>6y/o) age groups over the last two years as retrospectively. After the assessment of the seizures types, epilepsy syndromes, and etiologies; the data were also compared to evaluate if having correlation between epileptogenic zone and seizure subtypes in both ILAE 2010 and SSC.

RESULTS

ILAE 2010 indicated that 66.7% of the patients had focal seizures, 15.9% had generalized seizures, and 14.4% had seizures of unknown origin. The SSC revealed that the most frequent seizure type was simple seizures (56.5%), second frequent one was complex motor seizures (46.4%) and dialeptic seizures (39.9%). To predict epileptogenic zone, SSC was found to be more specific than ILAE in terms of the more subgroups of SSC were related to the more subgroups of epileptogenic zone (p<0.05). Furthermore, there was a clear correlation between focal foci and specific seizure types in older ages, while many foci caused to same seizure types and tend to no clear focal foci with generalized onset in younger ages. On the other hand, the relationship between epileptogenic zone and etiology was more remarkable in the five dimensional classification.

SIGNIFICANCE

Preference of seizure classification system is unique for each patient and depends on requirements. Therefore, one dimension cannot be sufficient for evaluation the nature of the seizures in some patients. Furthermore, age related evolution of the seizure types should not be ignored due to ongoing maturation state of the brain. ILAE 2010 and SSC have weak and strong points compared to each other. Semiological seizure classification is more informative in terms of identifying the epileptogenic zone which may be important in specific occasions like pre-surgical work up, while ILAE is simple and easier method which can be applied for seizure description and their characteristics in daily practice.

Inter- and intraobserver agreement of seizure behavior scoring in the amygdala kindled rat

INTRODUCTION

The Racine scale is a 5-point seizure behavior scoring paradigm used in the amygdala kindled rat. Though this scale has been applied widely in experimental epilepsy research, studies of reproducibility are rare. The aim of the current study was, therefore, to assess its interobserver variability and intraobserver variability.

MATERIAL AND METHODS

A video database set was acquired in the course of amygdala kindling of 67 Wistar rats. Six blinded observers received scoring instructions and then viewed a set of 15 random videos (session #1). Next, each observer scored 379 to 1048 additional videos (session #2) and finally scored the same set of 15 videos again (session #3). Scores included the occurrence of seizures (yes or no), the total seizure time (start of stimulus until the absence of seizure behavior), and the highest Racine stage. Interobserver variability and intraobserver variability were assessed in and between sessions #1 and #3 using a 2-way mixed intraclass correlation or Cohen's kappa depending on the variable.

RESULTS

Interobserver agreement in session #1 was 0.664 for seizure occurrence, 0.861 for total seizure time, and 0.797 for the highest Racine stage. In session #3, interobserver agreement on seizure occurrence declined to 0.492, total seizure time declined to 0.625, and agreement for the highest Racine stage was 0.725. Interobserver agreement was scored insufficiently on focal R2 seizures in both sessions (0.287 and 0.182). Intraobserver agreement reached >0.80 agreement for seizure occurrence, highest seizure score, and total seizure time in 3 out of 4 observers. Racine's scale stage 2 seizure scores were only 0.135 in one observer but 0.650, 0.810, and 0.635 in the other observers.

DISCUSSION AND CONCLUSION

Overall, interobserver agreement and intraobserver agreement in scoring with Racine's scale were adequate. However, because interobserver agreement declined after a period of individually scoring videos, we suggest periodic repetition of the standardized instruction in the course of evaluating videos in order to ensure reproducible results.

Autoantibodies to neuronal antigens in children with new-onset seizures classified according to the revised ILAE organization of seizures and epilepsies

PURPOSE

Potentially pathogenic autoantibodies are found increasingly in adults with seizure disorders, including focal seizures and those of unknown cause. In this study, we investigated a cohort of children with new-onset seizures to see whether there were autoantibodies and the relationship to any specific seizure or epilepsy type.

METHODS

We prospectively recruited 114 children (2 months to 16 years) with new-onset seizures presenting between September 2009 and November 2011, as well as 65 controls. Patients were clinically assessed and classified according to the new International League Against Epilepsy (ILAE) organization of seizures and epilepsies classification system. Sera were tested for autoantibodies to a range of antigens, blind to the clinical and classification details.

KEY FINDINGS

Eleven (9.7%) of 114 patients were positive for one or more autoantibodies compared to 3 of 65 controls (4.6%, p = ns). Patients had antibodies to the voltage-gated potassium channel (VGKC) complex (n = 4), contactin-associated protein-like 2 (CASPR2) (n = 3), N-methyl-d-aspartate receptors (NMDARs) (n = 2), or VGKC-complex and NMDAR (n = 2). None had antibodies to glutamic acid decarboxylase, contactin-2, or to glycine, 2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl) propionic acid (AMPA), or γ-aminobutyric acid B receptors. Ten of these 11 patients were classified as having epilepsy according to the new ILAE organization of seizures and epilepsy. Although, there were no significant differences in the demographic and clinical features between antibody-positive and antibody-negative patients, the classification of "unknown cause" was higher in the antibody positive (7/10; 70%) compared with the antibody negative subjects (23/86; 26.7%; p = 0.0095, Fisher's exact test). Furthermore, four of these seven patients with epilepsy (57.1%) were classified as having predominantly focal seizures compared with 12 of the 86 antibody-negative patients (13.9%; p = 0.015).

SIGNIFICANCE

Because autoantibodies were more frequent in pediatric patients with new-onset epilepsy of "unknown cause," often with focal epilepsy features, this group of children may benefit most from autoantibody screening and consideration of immune therapy.