Auditory brainstem responses and behavioural responses in pre-term infants.

Area of Science:

• Neonatal audiology
• Developmental pediatrics

Background:

• Preterm infants often experience hearing issues.
• Auditory brainstem responses (ABRs) and behavioral audiometry are key diagnostic tools.

Purpose of the Study:

• Compare ABRs and behavioral thresholds in preterm and full-term infants around 40 weeks post-conceptional age.
• Track hearing changes in preterm infants during the first year of life.
• Investigate if being small-for-dates impacts auditory development.

Main Methods:

• Measured ABR thresholds, latencies (Waves I, V), and I-V interwave latency.
• Assessed behavioral audiometric thresholds using behavioral observation and conditioned orientation-reflex audiometry.
• Included 25 preterm infants (small-for-date and appropriate-for-date) and full-term controls.

Main Results:

• Preterm infants showed normal ABR thresholds and latencies, comparable to full-term controls.
• ABRs were not significantly affected by infants being small-for-dates.
• Behavioral audiometry revealed poorer thresholds in preterm infants (42% AFD, 30% SFD responding at ≤90 dB) compared to full-term infants (all responded at ≤85 dB).
• Most preterm infants' behavioral thresholds normalized by 12 months.

Conclusions:

• Auditory brainstem responses are resilient in preterm infants, even those small-for-dates.
• Behavioral hearing assessment highlights initial auditory delays in preterm infants.
• Early auditory deficits in preterm infants largely resolve by one year of age.