Objective: Electroencephalographic suppression bursts (SBs) in newborns usually indicate a grave neurodevelopmental syndrome; however, they have heterogeneous etiologies and noteworthy phenotypes and outcomes.
Methods: We studied 22 newborns with electroencephalographic SBs with varied etiologies, electroencephalographic evolution, associated changes of seizure semiology, and neurodevelopmental outcomes.
Results: Five patients had mitochondrial disease, 3 nonketotic hyperglycinemia, 1 citrullinemia, 6 brain structural disease (hydrocephalus with porencephaly: 3, Rubinstein-Taybi syndrome: 1, Aicardi’s syndrome: 1, and Ohtahara syndrome with corpus callosum hypoplasia: 1), 6 severe hypoxic-ischemic encephalopathy (HIE), and 1 SB with an unknown etiology. The outcome was best in patients with unilateral SBs and treatable diseases like citrullinemia: they had mild developmental delays and unilateral SBs with focal structural anomalies. Patients with unilateral SBs had better outcomes, could walk at 3 years old (p<.001), and had better neurodevelopment (p<.001). Their life expectancy was not significantly longer than for patients with bilateral SBs, however.
Conclusion: In patients with predominantly synchronous SBs and without lesions in magnetic resonance images, the etiology is usually metabolic or genetic. Patients with synchronous SBs had worse outcomes; specifically, they usually could not walk. The neurodevelopmental outcomes were relatively better in patients with asynchronous rather than with synchronous SBs.