Neurophysiologic Assessment of Auditory Brain Maturation and Learning in Extremely Premature Infants † 1291

Abstract

Extremely preterm infants are at risk for cognitive morbidity. Abnormal development of auditory brain pathways may contribute to later auditory processing defects, language delays, or learning disabilities. The purpose of this study was to evaluate developing cognitive pathways in 28 extremely preterm infants (< 29 weeks) compared with 34 healthy control infants using event related potentials (ERPs), an electrophysiologic technique used to test regional maturation of the brain. All infants had normal hearing. Auditory ERPs were obtained during active sleep at 36, 40, and 44 weeks postmenstrual age. Two paradigms were used for all tests. First, to evaluate regional brain maturation, stimuli were a speech sound and a non-speech sound. Second, to evaluate auditory recognition memory, stimuli were voice recordings of the subject's mother and a stranger. For each paradigm, stimuli were alternately presented for a total of 100 trials while brain activity was recorded over midline and lateral electode sites for 2000 msec. Artifact-free trials were cross averaged by stimulus. Averages were analyzed by integrating the area under the curve. For the ERPs elicited by the non-speech sound, a maturational score from 1-5 was assigned (Kurtzberg). Areas were compared for the mother/stranger ERPs using ANOVA. Control infants' ERP patterns were used to evaluate preterm infants' responses. (Study infant's ERP responses will be correlated with language development in follow-up).