Rethinking the definition of neonatal status epilepticus

Neonatal status epilepticus (NSE) is associated with poor survival and adverse neurological outcomes. However, current definitions only partially account for the unique pathophysiology of the neonatal brain and the clinical context of acute symptomatic seizures. To address this gap, international efforts are underway to develop a more specific and context-appropriate definition for the neonatal period. While definite evidence in human newborns is still being gathered, we critically examine three conceptual approaches to defining NSE. We reviewed the relevant literature in order to discuss: 1) outcome-based definitions, 2) definitions based on the likelihood of spontaneous seizure termination, and 3) definitions guided by the decreasing probability of response to antiseizure medication.

Although important knowledge gaps remain, emerging evidence is beginning to shape future directions in research and clinical care. A definition grounded in neonatal-specific mechanisms and clinical realities holds promise for improving neurodevelopmental outcomes in critically ill newborns.

• Historical definition of neonatal status epilepticus (NSE) requires a single seizure (or recurrent seizures without return to baseline neurologic conditions) lasting ≥ 30 minutes. • With continuous monitoring, various definitions of a "high" seizure burden (SB) were preferentially used.

• Evidence is being gathered for definitions based on declining probability of spontaneous seizure termination, on outcome, and on declining probability of drug response.. • Based on our literature review, we propose to consider any single seizure lasting 5 minutes as early NSE.