Neonatal auditory brain stem responses from ipsilateral and contralateral recording montages

Area of Science:

• Neuroscience
• Audiology
• Pediatrics

Background:

• Auditory brain stem responses (ABR) are crucial for assessing auditory pathway function in neonates.
• Understanding typical ABR waveforms in infants is essential for accurate hearing and neurological assessments.
• Contralateral ABR recordings in neonates are less understood than ipsilateral ones.

Purpose of the Study:

• To characterize the morphology and amplitude of ipsilateral and contralateral auditory brain stem responses in neonates.
• To compare neonatal contralateral ABR findings with established adult ABR patterns.
• To highlight potential diagnostic challenges arising from neonatal contralateral ABR characteristics.

Main Methods:

• Auditory brain stem responses were recorded from 10 neonates (37-43 weeks gestation) with normal auditory function.
• Both ipsilateral and contralateral recording montages were utilized for each ear.
• Responses were analyzed for waveform morphology and amplitude at various sound levels (e.g., 30 dB nHL).

Main Results:

• Neonatal contralateral ABRs exhibited distinct waveform morphologies compared to ipsilateral responses.
• A prominent positive deflection preceded the ipsilateral wave III, followed by negative waves aligning with ipsilateral wave V.
• The amplitude of contralateral responses was notably small, with clear recordings obtained in only 7 of 20 ears at 30 dB nHL.

Conclusions:

• Neonatal contralateral ABR morphology significantly differs from ipsilateral ABRs and adult contralateral ABRs.
• Interpreting neonatal contralateral ABRs based on adult criteria may lead to misdiagnosis of hearing impairment or neurological issues.
• Careful consideration of unique neonatal contralateral ABR characteristics is vital for accurate clinical interpretation.