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Abstract
Background and Objectives We aimed to determine the population-based cumulative incidence and prevalence of developmental and epileptic encephalopathies (DEEs) and intellectual disability and epilepsy (ID+E) in children. We analyzed the cumulative incidence of specific epilepsy syndromes.
Methods Children younger than 16 years with a DEE or ID+E were ascertained using EEG records from 2000 to 2016 in the Wellington region of New Zealand. Epilepsy syndromes were diagnosed on medical record and EEG review. Point prevalence and cumulative incidence for children with epilepsy and developmental impairment, DEE and ID+E were calculated. Cumulative incidence for each epilepsy syndrome was calculated.
Results The cohort comprised 235 children (58% male) with developmental impairment and epilepsy, including 152 (65%) with DEE and 83 (35%) with ID+E. The median age of seizure onset was 15.4 months (range day 1–15 years). The median follow-up from seizure onset was 7.9 years (range 0–18.2 years). Point prevalence for the broad group of children with epilepsy and developmental impairment was 175/100,000 children (95% CI 149–203; DEE 112 and ID+E 63/100,000 children). Cumulative incidence for DEE was 169/100,000 children (95% CI 144–199) and that for ID+E was 125/100,000 children (95% CI 95.4–165). Cumulative incidence per 100,000 children was as follows: infantile epileptic spasms syndrome 58.2 (95% CI 45.0–75.3), epilepsy with myoclonic-atonic seizures 16.4 (95% CI 9.69–27.7), Lennox-Gastaut syndrome 13.2 (95% CI 4.1–41.9), and Dravet syndrome 5.1 (95% CI 2.1–12.2). Fifty/152 (33%) of children with DEE and 70/83 (84%) with ID+E could not be diagnosed with a known epilepsy syndrome.
Discussion Epilepsy and developmental impairment before the age of 16 years occurs in 1 in 340 children, with 1 in 590 having a DEE and 1 in 800 having ID+E. These individuals require significant health and community resources; therefore, these data will inform complex health service and education planning. Epidemiologic studies have focused on early childhood–onset DEEs. These do not fully reflect the burden of these disorders because 27% of DEEs and 70% of ID+E begin later, with seizure onset after the age of 3 years. Understanding the cumulative incidence of specific syndromes together with the broad group of DEEs is essential for the planning of therapeutic trials. Given trials focus on specific syndromes, there is a risk that effective therapies will not be developed for one-third of children with DEE.
Glossary
- DEE=
- developmental and epileptic encephalopathy;
- DEE-SWAS=
- DEE with spike-and-wave activation in sleep;
- EE-SWAS=
- epileptic encephalopathy with spike-and-wave activation in sleep;
- EEM=
- epilepsy with eyelid myoclonia;
- EME=
- early myoclonic encephalopathy;
- EMAtS=
- epilepsy with myoclonic-atonic seizures;
- FIRES=
- febrile infection–related epilepsy syndrome;
- FS+=
- febrile seizures plus;
- GTCS=
- generalized tonic-clonic seizures;
- ID=
- intellectual disability;
- ID+E=
- ID and epilepsy;
- IESS=
- Infantile epileptic spasms syndrome;
- ILAE=
- International League Against Epilepsy;
- JAE=
- juvenile absence epilepsy;
- JME=
- juvenile myoclonic epilepsy;
- LKS=
- Landau-Kleffner syndrome;
- LGS=
- Lennox-Gastaut syndrome;
- MWW=
- Mann-Whitney-Wilcoxon;
- OR=
- odds ratio;
- PYAR=
- person-years at risk;
- SeLEAS=
- self-limited epilepsy with autonomic seizures
Footnotes
Go to Neurology.org/N for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
Submitted and externally peer reviewed. The handling editor was Associate Editor Barbara Jobst, MD, PhD, FAAN.
- Received July 29, 2022.
- Accepted in final form November 16, 2022.
- © 2022 American Academy of Neurology
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