Electroencephalographic Background and Electrographic Abnormalities in Term and Near-Term Neonates With Hyperbilirubinemia: An Observational Study

Abstract

Background: Neonatal hyperbilirubinemia is a common condition that may progress to bilirubin-induced neurological dysfunction and permanent neurological injury. Electroencephalography (EEG) provides information regarding cerebral electrical activity, brain maturation, background organization, and electrographic seizures. Although abnormalities in sleep–wake cycling have been described in neonates with hyperbilirubinemia, less attention has been given to other EEG abnormalities, including background abnormalities and electrographic seizure activity.

Objective: To characterize EEG background abnormalities, age-related EEG maturation, and electrographic seizure or brief potentially ictal rhythmic discharge (BIRD) activity in term and near-term neonates with hyperbilirubinemia.

Methods: This observational cross-sectional study enrolled 38 term and near-term neonates with hyperbilirubinemia admitted to the neonatal intensive care unit of Cairo University Children’s Hospital. Each infant underwent at least one hour of polygraphic EEG recording together with clinical and laboratory assessment. EEG background amplitude, age-appropriate graphoelements, age-dependent synchrony and continuity, and seizure/BIRD activity were assessed.

Results: Among the 38 analyzed neonates, 31 (81.6%) had normal background amplitude, while 7 (18.4%) had abnormal background amplitude. Age-appropriate graphoelements were present in 36 neonates (94.7%), while abnormalities were identified in 2 (5.3%). Age-dependent synchrony and continuity were normal in 34 neonates (89.5%) and abnormal in 4 (10.5%). Seizure activity or BIRDs were documented in 4 neonates (10.5%). One neonate had electrographic seizure activity without overt clinical seizures. The observed epileptic activity was predominantly localized to the temporal and occipital regions in the representative recordings.

Conclusion: EEG abnormalities involving background activity, age-related organization, and electrographic seizure activity were observed in a subset of term and near-term neonates with hyperbilirubinemia. These findings demonstrate that EEG may identify electrographic abnormalities that are not necessarily evident from clinical examination alone. However, because EEG was performed after treatment had already been initiated and no healthy gestational-age-matched control group was included, the findings should be interpreted as descriptive associations rather than evidence of a direct causal effect of bilirubin on EEG activity.