Cross-talk in otoacoustic emission probes

Area of Science:

• Audiology
• Biomedical Engineering
• Acoustics

Background:

• Otoacoustic emissions (OAEs) are crucial for hearing diagnostics.
• Accurate OAE measurements depend on the integrity of specialized probes.
• Internal coupling, or cross-talk, between sound sources and microphones within OAE probes is a potential source of error.

Purpose of the Study:

• To evaluate the internal coupling (cross-talk) of several commercial otoacoustic emission probes.
• To identify the sources of cross-talk in specific probe models.
• To assess the impact of cross-talk on the accuracy of acoustic calibrations.

Main Methods:

• Tested commercial OAE probes (Virtual 330, Etymotic ER-10/ER-10B, Otodynamics ILO88/ILO92).
• Simulated the human ear canal using a test cavity.
• Measured probe response with sound source or microphone inlets blocked to quantify cross-talk.

Main Results:

• Severe cross-talk was found in the Virtual 330 and Etymotic ER-10B probes.
• Sound radiation through flexible silicone tubing was identified as the primary cause of cross-talk.
• Otodynamics ILO88/ILO92 and original Etymotic ER-10 probes demonstrated acceptable cross-talk levels.
• Substituting harder-walled tubing reduced cross-talk in affected probes.

Conclusions:

• Excessive cross-talk in certain OAE probes is primarily acoustic/mechanical, not electromagnetic.
• Artifacts from cross-talk can contaminate collected OAE data.
• Manufacturers should establish and document cross-talk standards for OAE probes.