Developmental delays identified in children with prolonged seizures

A study led by researchers at the UCL Institute of Child Health (ICH) has found that convulsive status epilepticus (CSE), one of the most common seizures to occur in young children, is associated with developmental impairments.

CSE is a prolonged seizure, normally lasting more than thirty minutes, and can occur with or without fever. The incidence of CSE in childhood has been estimated to be around 20 cases per 100,000 per year, according to a previous study in the Lancet. The present research identified developmental delays in children within six weeks of the neurological emergency taking place. The study, published in the journal Epilepsia, also suggests that neurodevelopmental impairments continue to be present one year after CSE.

This is the first time a study of this nature has focused on the period immediately following a CSE seizure and has considered all types, not solely febrile seizures (those that present with a fever). This has proven crucial to the investigation, as most CSE events affect children below the age of three, at a time of critical growth and development for the brain.

Lead author Dr Marina Martinos, UCL Institute of Child Health, explains: “Our study is unprecedented in determining how CSE impacts early childhood development and whether this type of seizure has long-term adverse affects. The overall findings are an important addition to medical evidence.”

Researchers studied 54 children between one and forty-two months of age who had experienced at least one CSE event. CSE episodes were classified as prolonged febrile seizures (PFS) or nonfebrile CSE. All participants underwent neuropsychological assessments and imaging scans within six weeks of the CSE event and again at one year. Developmental skills were measured in children who had seizures and were compared to children without seizures with normal development.

Half of the participants had PFS and the other half had non-febrile CSE, with assessments carried out at an average of 38 days following the seizure. At the one-year follow up, children with nonfebrile PFS had worse developmental outcomes than those with PFS, and children in the PFS group had poorer developmental skills than those in the control group. The authors found that seizure characteristics (e.g. duration) were not a significant predictor of developmental performance.

Dr Martinos concludes: “We found developmental impairments in children following CSE, including those with PFS who normally do not display neurological issues prior to the seizure. The fact that neurodevelopmental impairments are still present at one year after the episode suggests that the CSE event is not having just a transient effect on developmental abilities. The CSE may have a longer lasting impact on future development through a more permanent reorganization of functional brain networks – a reorganization that may have already taken place when we first assess these children.”

Alternatively, the authors comment, these data suggest that the neurodevelopmental impairments observed predate the seizure even in those with no neurological priors.

The authors propose that further studies that include neurocognitive techniques are necessary to enhance understanding of the long-term impact of CSE on child development.