Neonatal hearing screening using otoacoustic emissions elicited by maximum length sequences

Area of Science:

• Audiology
• Neonatal Medicine
• Biomedical Engineering

Background:

• Otoacoustic emissions (OAEs) are crucial for objective hearing assessment in newborns.
• Current OAE methods require refinement for improved clinical utility and automatic evaluation.
• Transient evoked OAEs (TEOAEs) are a standard technique, but efficiency can be enhanced.

Purpose of the Study:

• To provide statistical data on OAE measurements in newborns.
• To evaluate the efficacy of maximum length sequences (MLS) for TEOAE recording.
• To identify parameters for objective and automatic response evaluations in neonatal hearing screening.

Main Methods:

• Transient evoked otoacoustic emissions (TEOAEs) were recorded in 129 newborns using maximum length sequences (MLS).
• Stimulus rates of up to 2000/sec were utilized, enabling rapid data acquisition.
• Analysis included signal-to-noise ratio, non-linear responses, time/frequency analysis, and signal power.

Main Results:

• Optimal signal-to-noise ratio (S/N) was achieved with >60% recording rejection.
• Non-linear responses were characterized by level and rate dependencies, with amplitude suppression at higher stimulus rates.
• Time/frequency analysis revealed a consistent falling frequency over time, characteristic of OAEs.
• Emission power analysis confirmed reliable linear recordings in newborns, with stimulus decay within 3 ms.

Conclusions:

• The MLS technique is effective for neonatal TEOAE measurement due to fast recording and noise rejection.
• Findings provide valuable statistical information for interpreting OAE results in newborns.
• The study supports the development of screening equipment with automatic response evaluation for neonatal hearing.