Maturation of high-density EEG oscillatory visual responses in infants born preterm

Background: Children born preterm are at risk for developmental cerebral visual impairment. Several modalities of visual evoked potentials recording have been used to approach prognosis. The recent development of high-density EEG protocols allows evaluation of the oscillatory content of cortical activities evoked by specific stimulation. We aimed to document maturational EEG changes in response to visual stimulation in infants born preterm. Aim: to document maturational EEG changes in response to visual stimulation in infants born preterm. Material and methods: 12 newborn infants (8 boys/4 girls) born preterm (28-31 weeks of gestation) were recorded at term age and 3 months later using the ActiveTwo system (Biosemi) high-density EEG. Exclusion criteria were craniofacial congenital malformations, known genetic syndrome. No infants had retinopathy, intraventricular hemorrhage or cystic periventricular leukomalacia. We used size-adapted head caps with 64 sintered active Ag/AgCl electrodes positioned according to the 10/20 system. Sampling rate was 2048 Hz. We performed EEGLab analysis of theta, alpha, beta and gamma frequency spatiotemporal contents (incl. event-related spectral perturbation and intertrial coherence) of event related potentials evoked by slow (1Hz) and fast (9Hz) visual flash stimulation. Summed ear lobe potentials were used as reference. We used 1 Hz high-pass filter, 60 Hz low-pass filter and 48-52 Hz notch filter.