MRI, EEG may predict children’s epilepsy risk after long febrile seizures

By Helen Albert, Senior medwireNews Reporter

Children who have prolonged febrile seizures (FSE) are at increased risk for magnetic resonance imaging (MRI) observed hippocampal injury and abnormal hippocampal and temporal development, show results from the Consequences of Prolonged Febrile Seizures in Childhood (FEBSTAT) study.

The researchers also found that 45.2% of children with FSE had abnormal patterns on encephalography (EEG), with 6.5% showing patterns similar to those with epilepsy.

"Our goal has been to develop biomarkers that will tell us whether or not a particular child is at risk for epilepsy. This could in turn help us develop strategies to prevent the disorder," said lead FEBSTAT investigator Shlomo Shinnar (Albert Einstein College of Medicine, New York City, USA) in a press statement.

Seizures occurring as a result of high fever are common and largely harmless, affecting 3-4% of all children. However, having one or more prolonged febrile seizure of 30 minutes or longer (FSE) is thought to increase a child's risk for later epilepsy by 30-40%.

For FEBSTAT, Shinnar and colleagues recruited 199 children aged 1 month to 5 years who had experienced at least one fever-associated seizure of over 30 minutes. A group of 96 children who had experienced one simple febrile seizure (less than 30 minutes) were enrolled to act as controls.

Overall, 191 children had MRI imaging of the brain and all 199 children underwent EEG. As reported in two papers in Neurology, 11.5% of children in the FSE group had definite MRI observed abnormalities in the hippocampus compared with none in the control group.

In addition, developmental hippocampal and temporal abnormalities were significantly more common in the FSE group than in controls, at 10.5% versus 2.1% and 7.9% versus 1.0%, respectively. But abnormalities in other brain areas were observed at a similar frequency in both groups.

The most common EEG abnormality was focal slowing or weakening, seen in 47 and 25 children with FSE, respectively. Abnormalities on EEG were most pronounced over the temporal area in the majority of the FSE children.

Notably, hippocampal abnormalities on MRI increased the risks for focal slowing or attenuation in children with FSE more than threefold.

"If MRI and EEG findings associated with FSE ultimately do correlate with epilepsy, they could be used to identify kids who are at risk and who might benefit from research on preventative therapies for epilepsy," independent expert Vicky Whittemore (National Institute of Neurological Disorders and Stroke Neuroscience Center, Bethesda, Maryland, USA) told the press.

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