A probe earmold system for measuring eardrum SPL under hearing-aid conditions

Area of Science:

• Audiology
• Acoustics
• Biomedical Engineering

Background:

• Accurate measurement of sound pressure level (SPL) at the eardrum is crucial for hearing aid fitting.
• Existing methods may be invasive or inaccurate in occluded ear conditions.

Purpose of the Study:

• To develop and validate a miniature probe-microphone assembly integrated with an earmold (PE system) for measuring eardrum SPL.
• To assess the accuracy of the PE system in human ears under hearing-aid conditions.

Main Methods:

• A probe-earmold (PE) system was designed, integrating the probe with the earmold to avoid ear canal intrusion.
• Previous validation was performed using an ear simulator, showing +/- 3 dB accuracy up to 6.0 kHz.
• A behavioral experiment on human ears compared pure-tone thresholds from a conventional earphone to those from the PE system with a hearing aid receiver.

Main Results:

• The PE system demonstrated accurate eardrum SPL measurements up to 6.0 kHz in an ear simulator.
• No statistically significant differences were found between pure-tone thresholds measured by the conventional earphone and the PE system on human ears.
• These findings confirm the simulator data and validate the PE system's accuracy in occluded ears.

Conclusions:

• The developed probe-earmold (PE) system accurately measures sound pressure level (SPL) at the eardrum in occluded ears up to 6.0 kHz.
• The PE system offers a reliable tool for audiological assessments and hearing aid fitting.
• Validation on human ears confirms the utility of the PE system for clinical applications.