Predicting hearing aid response in real ears

Area of Science:

• Audiology
• Acoustics
• Biomedical Engineering

Background:

• Individual ear canal acoustics and hearing aid characteristics create significant variations in sound pressure spectra.
• Existing models often lack accuracy at higher frequencies, limiting precise hearing aid fitting.

Purpose of the Study:

• To develop and validate an electrical analog model for predicting sound pressure spectra in the ear canal with hearing aids.
• To assess the model's accuracy for high-frequency hearing aid fitting.

Main Methods:

• An electrical analog model of the ear and hearing aid system was developed.
• Model predictions were verified using an ear simulator (coupler) from 300 Hz to 8000 Hz.
• Measurements were conducted on three hearing aid types across five human ears, comparing predicted vs. measured responses.

Main Results:

• The model and measurement procedure showed good agreement on the coupler (300–8000 Hz).
• Fair agreement between measured and predicted responses was achieved in human ears from 300 Hz to approximately 6000 Hz.
• Probe misalignment was identified as a significant error source; the model is theoretically valid up to 10 kHz.

Conclusions:

• The electrical analog model provides a viable method for predicting hearing aid response in the ear canal, particularly at higher frequencies.
• This study offers a novel solution for high-frequency hearing aid fitting, addressing a gap in previous research.