Related Experiment Video
Updated: May 24, 2026
Infant Auditory Processing and Event-related Brain Oscillations
Published on: July 1, 2015
Influence of gestational age and postnatal age on speech sound processing in NICU infants
Alexandra P F Key1, E Warren Lambert, Judy L Aschner
1Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37203, USA. sasha.key@vanderbilt.edu
Insights
Infant speech sound perception is influenced by both gestational age (GA) and postnatal age (PNA). Brain maturity at birth impacts how infants benefit from early experiences, affecting auditory processing.
Area of Science:
- Neuroscience
- Developmental Psychology
- Speech and Hearing Sciences
Background:
- Infant speech sound perception is crucial for language development.
- Understanding the impact of prematurity on auditory processing is vital.
- Auditory event-related potentials (ERPs) offer insights into neural responses to sound.
Purpose of the Study:
- To investigate the effects of gestational age (GA) and postnatal age (PNA) on speech sound perception in preterm infants.
- To quantify the efficiency of speech perception using auditory event-related potentials (ERPs).
- To determine if brain maturity at birth influences the benefits of postnatal experience.
Main Methods:
- Recorded auditory event-related potentials (ERPs) in 50 NICU infants (24-40 weeks GA) before discharge.
- Presented speech sounds (syllables) including vowel and consonant contrasts.
- Quantified speech perception efficiency by analyzing ERP amplitude differences at specific time windows.
Main Results:
- Both gestational age (GA) and postnatal age (PNA) significantly affected speech sound processing.
- Effects were more pronounced for consonant contrasts than vowel contrasts.
- Increasing PNA enhanced sound discrimination in infants born at or after 30 weeks GA, but not in those born earlier.
Conclusions:
- A minimum level of brain maturity at birth is necessary for infants to benefit from postnatal auditory experiences.
- Both gestational and postnatal ages are critical factors when assessing infant brain responses to speech sounds.
- These findings have implications for early intervention and developmental monitoring in preterm infants.
Abstract:
The study examined the effect of gestational (GA) and postnatal (PNA) age on speech sound perception in infants. Auditory event-related potentials (ERPs) were recorded in response to speech sounds (syllables) in 50 infant NICU patients (born at 24-40 weeks gestation) prior to discharge. Efficiency of speech perception was quantified as absolute difference in mean amplitudes of ERPs in response to vowel (/a/-/u/) and consonant (/b/-/g/, /d/-/g/) contrasts within 150-250, 250-400, 400-700 ms after stimulus onset. Results indicated that both GA and PNA affected speech sound processing. These effects were more pronounced for consonant than vowel contrasts. Increasing PNA was associated with greater sound discrimination in infants born at or after 30 weeks GA, while minimal PNA-related changes were observed for infants with GA less than 30 weeks. Our findings suggest that a certain level of brain maturity at birth is necessary to benefit from postnatal experience in the first 4 months of life, and both gestational and postnatal ages need to be considered when evaluating infant brain responses.
