Related Experiment Video
Updated: Jun 3, 2026
A Behavioral Screen for Heat-Induced Seizures in Mouse Models of Epilepsy
Published on: July 12, 2021
Distribution of febrile seizure duration and associations with development
Dale C Hesdorffer1, Emma K T Benn, Emilia Bagiella
1Gertrude H. Sergievsky Center, Departments of Epidemiology, Biostatistics, and Neurology, Columbia University, New York, NY 10032, USA. dch5@columbia.edu
Insights
Febrile seizures (FSs) in children are best described by two distinct duration populations. This study suggests defining prolonged febrile seizures as lasting 10 minutes or more, associated with developmental delays.
Area of Science:
- Pediatric Neurology
- Epileptology
- Clinical Epidemiology
Background:
- Previous definitions of prolonged febrile seizures (FSs) lacked empirical evidence.
- Defining FS duration is crucial for clinical management and research.
Purpose of the Study:
- To analyze the distribution of first-time FS duration in children.
- To identify factors associated with prolonged FSs.
Main Methods:
- A cohort of 158 children with first FSs was studied.
- FS duration data were modeled using a two-component mixture exponential distribution.
- Logistic regression analyzed associations between prolonged FSs and baseline characteristics.
Main Results:
- The median FS duration was 4.0 minutes.
- Two populations of FS duration were identified: short (82.3%, mean 3.8 min) and long (17.7%, mean 39.8 min).
- Prolonged FSs were linked to developmental delay and younger age at first FS.
Conclusions:
- FS duration follows a bimodal distribution, similar to afebrile seizures.
- Developmental delay and younger age are risk factors for prolonged FSs.
- The findings support defining 10 minutes as the upper limit for a simple FS.
Objective:
In prior studies of febrile seizures (FSs), prolonged FSs were defined, absent empirical evidence, as lasting 10 or 15 minutes or more. We assessed the distribution of FS duration in a cohort with first FSs, and the association between FS duration and baseline characteristics of the children.
Methods:
We calculated the observed cumulative probability, S(t), that a FS would last at least t minutes, S(t) = exp(-t/τ). Data were also fit using a model obtained as the sum of 2 exponential distributions (S[t] = αexp[-t/τ(1) ] + [1 - α]exp[-t/τ(2) ]). After assessing the best fit, the cutoff defining long FS was determined. Logistic regression was used to examine associations between long FSs and baseline characteristics, behavior, and development.
Results:
In 158 children with a first FS, median duration was 4.0 minutes. Duration of FS was best fit by a 2-component mixture exponential model. Using this model, we identified 1 population that accounts for 82.3% of FSs and has a mean duration of 3.8 minutes (short FS) and a second population that accounts for 17.7% of FSs and has a mean duration of 39.8 minutes (long FS). Long FSs were significantly associated with developmental delay (p = 0.010) and delays and younger age at first FS (p = 0.048).
Interpretation:
Like the distribution of afebrile seizure duration in children, the distribution of first FS duration is best modeled by assuming 2 populations. Developmental delay and younger age are associated with prolonged FSs. Our data lend further support to defining 10 minutes as the upper limit for a simple FS.
Related Concept Videos
01:20Seizures l: Introduction
01:13Seizures: Classification
Seizures are typically classified into two main categories: focal and generalized seizures.
Focal Seizures
Focal seizures originate from specific regions of the brain. These seizures are further sub-classified into two types:
01:19Seizures ll: Types
01:22Epilepsy ll: Types
01:24Epilepsy and Seizures: Overview
Various factors can trigger epilepsy, including genetic factors, brain damage, metabolic causes, and unknown etiology. Diagnosis of epilepsy involves electroencephalography (EEG), which...
01:26Patterns of Fever