Hemisphere differences in speech-sound event-related potentials in intensive care neonates: associations and predictive value for development in infancy

Abstract

Neurodevelopmental delays in intensive care neonates are common but difficult to predict. In children, hemisphere differences in cortical processing of speech are predictive of cognitive performance. We hypothesized that hemisphere differences in auditory event-related potentials in intensive care neonates are predictive of neurodevelopment in infancy, even in those born preterm. Event-related potentials to speech sounds were prospectively recorded in 57 infants (gestational age 24-40 weeks) prior to discharge. The Developmental Assessment of Young Children was performed at 6 and 12 months. Hemisphere differences in mean amplitudes increased with postnatal age (P < .01) but not with gestational age. Greater hemisphere differences were associated with improved communication and cognitive scores at 6 and 12 months, but decreased in significance at 12 months after adjusting for socioeconomic and clinical factors. Auditory cortical responses can be used in intensive care neonates to help identify infants at higher risk for delays in infancy.

Keywords: auditory event-related potentials; lateralization; neonatal intensive care; neurodevelopment; preterm.

Figure 1

Event-potential responses to speech sounds. (A) Electrode clusters on scalp locations. (B) Event-potential responses averaged across all study subjects. Mean amplitudes (in μV) averaged for all 57 patients in the 250- to 400-ms time window were: F3 = 1.48 (±0.19), F4 = 1.31 (±0.19), T5 = −1.1 (±0.11), T6 = −0.5 (±0.11). F3, frontal left; F4, frontal right; T5, temporal left; T6, temporal right.

Figure 2

Hemisphere differences in mean amplitudes responses to speech sounds as a function of postnatal age. (A) Frontal locations. (B) Temporal locations. Line represents linear regression fit.

Figure 3

Associations of hemisphere difference in amplitudes and 6-month developmental scores. Normative sample n = 50; nonnormative sample n = 7 (4 infants with severe white matter injury [grade III or IV intraventricular hemorrhage], 1 infant with Turner syndrome, 2 with unilateral auditory neuropathy). Line represents linear regression fit. DAYC, Developmental Assessment of Young Children.