West syndrome: early remission is not assurance of normal final outcome

Interrater and Intrarater Agreement of Epileptic Encephalopathy Among Electroencephalographers for Children with Infantile Spasms Using the Burden of Amplitudes and Epileptiform Discharges (BASED) EEG Grading Scale: Study Design and Statistical Considerations

Background

Infantile spasms are a serious epilepsy syndrome with a poor prognosis. Electroencephalography (EEG) has been a key component in the prognosis and treatment of infantile spasms. This multi-center study protocol is developed to investigate interrater and intrarater agreement of an electroencephalographic grading scale—the Burden of Amplitudes and Epileptiform Discharges (BASED) score among electroencephalographers.

Methods

Thirty children, aged 0–2 years, with infantile spasms who were hospitalized in the Chinese PLA General Hospital will be recruited into this study by stratified sampling. Seven electroencephalographers from different Class A tertiary hospitals will select a 5-min epoch with the most severe epileptiform discharge, score the EEG reports, and provide the basis for the scoring. The 420 (30 × 7 × 2) scoring results provided by electroencephalographers in two rounds can be analyzed statistically using weighted kappa (weighted \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\kappa$$\end{document}κ) statstic, Fless’ kappa (Fless’ \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\kappa$$\end{document}κ) statistic, and intraclass correlation coefficient (ICC) to calculate the interrater and intrarater agreement.

Discussion

We will recruit more electroencephalographers than were included in previous studies to assess the interrater and intrarater agreement in the selection of 5-min EEG epochs, the BASED scores, and the basis for scoring. If the BASED score has an adequate interrater and intrarater agreement, the score will have more significance for guiding the clinical management and for predicting the prognosis of patients with infantile spasms.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40120-022-00382-4.

Evaluation of ten prognostic factors affecting the outcome of West syndrome

The aim of this study is to assess the seizure and developmental outcome and to determine the prognostic factors affecting the outcome of West syndrome in an etiologically well-defined large cohort. Demographic features, treatment modalities, etiology, seizure and developmental outcome of 216 cases with West syndrome were recorded retrospectively. Ten prognostic factors possibly affecting the outcome of West syndrome including (1) gender, (2) age at the onset (3) presence of seizures prior to spasms, (4) presence of asymmetric spasm, (5) presence of abnormal neurological signs, (6) treatment lag, (7) etiology, (8) drug chosen as the initial treatment, (9) response to initial treatment regardless of the kind, (10) development of other seizure types after spasms were evaluated in terms of seizure and developmental outcome. Twelve percent of the cases were developmentally normal at the end of 2-year follow-up. Ongoing seizures requiring antiepileptic drug medication at the last follow-up were noted in 90 % of the cases. Hypoxia (29 %), metabolic disorders (11 %), infectious diseases (9 %) and cerebral developmental disorders (8 %) were the most frequent etiological factors. Five of the ten prognostic factors (presence of seizures prior to spasms, presence of abnormal neurological signs, response to initial treatment regardless of the kind, etiology and development of other seizure types after spasms) were found to be statistically significant prognostic factors predicting the outcome. In conclusion, West syndrome is still a catastrophic epileptic encephalopathy. Preventable causes still constitute a substantial portion of the etiological causes of West syndrome. Therefore, the prevention of avoidable causes is at least as important as the treatment.