Prolonged neonatal seizures are often due to severe acute brain injuries and are known to be harmful to the brain. No predictors have yet been identified to distinguish at an early time-point between brief and long seizures. We investigated the duration of seizures in neonates to determine the relationship between the duration of a seizure and that of subsequent seizures.

We retrospectively reviewed video-electroencephalogram confirmed seizures of 30 preterm and 36 full-term neonates selected from patients admitted to the neonatal intensive care unit of Parma University Hospital. The duration and relationship between successive seizures were investigated. Statistical models were performed to evaluate the risk of long-lasting ictal events among neonates with seizures.

A positive monotonic relationship between the duration of successive seizures was identified. Most seizures were brief. No significant differences in seizure duration were found between preterm and full-term neonates, although a borderline significance emerged.

Neonatal seizures are usually brief, and as the seizure duration increases, the duration of the subsequent seizures tends to increase. We also suggest that full-term neonates could be at higher risk of experiencing long seizures compared to preterm neonates. In summary, estimating the seizure duration is critical to evaluating the optimal timing of therapeutic interventions and can help to predict how seizures evolve.