Changes in brainstem auditory response threshold in preterm babies from birth to late term.

Area of Science:

• Neonatal audiology
• Developmental neuroscience
• Pediatric hearing assessment

Background:

• Infant hearing development is crucial for long-term outcomes.
• Understanding hearing maturation in preterm infants is essential for early intervention.

Purpose of the Study:

• To track hearing threshold changes in preterm infants from 30 weeks postconceptional age to term.
• To determine the prevalence of elevated hearing thresholds in this population.

Main Methods:

• Brainstem Auditory Evoked Response (BAER) testing was performed on 268 infants (30-36 weeks gestation).
• A total of 656 BAER tests were conducted between 30 and 42 weeks postconceptional age.

Main Results:

• The average hearing threshold was 23 dB nHL at 30 weeks postconceptional age, decreasing to approximately 13 dB nHL by term (35-42 weeks).
• Hearing thresholds improved with age, decreasing at rates of 1.24 dB/week (30-36 weeks PCA) and 0.65 dB/week (30-42 weeks PCA).
• At term, 9% of infants exhibited elevated hearing thresholds (>20 dB nHL).

Conclusions:

• Hearing thresholds in preterm infants mature significantly between 30 weeks gestation and term.
• No substantial differences in hearing thresholds were observed between infants born at different gestational ages within the studied range.
• A notable percentage of infants (9%) present with elevated hearing thresholds at term, necessitating audiological follow-up.