Effects of perinatal asphyxia on cortical activity in two-year-old children.

Perinatal asphyxia can lead to clinical hypoxic-ischemic encephalopathy (HIE) associated with high morbidity and mortality, but less is known about long-lasting effects of perinatal asphyxia alone (PA). Here, we investigate how PA with versus without clinical HIE affects cortical activity networks at two years of age. Electroencephalographic (EEG) recordings were acquired during sleep from three cohorts of children (PA only (n = 10), PA with mild to moderate HIE (n = 8), and healthy controls (n = 37)), and we assessed the group differences in local cortical function and cortico-cortical networks. Compared with the healthy controls, both PA and HIE were linked to reduced frequency-specific amplitudes. In two-year-old children with PA, the amplitude-related networks were stronger at low frequencies and weaker at higher frequencies, however, two-year-olds with HIE showed decreased connectivity at all frequencies. Likewise, phase-related networks in children with PA were stronger at lower frequencies and weaker at higher frequencies. Local phase-amplitude coupling was affected by PA or HIE in only a few cortical regions. Our findings suggest that PA, even without clinical HIE, may be associated with long-lasting changes to both local cortical activity and the large-scale cortical networks, which could potentially affect normal brain functions.