Influence of transducer types on bone conduction hearing thresholds

Area of Science:

• Audiology
• Biomedical Engineering
• Hearing Science

Background:

• Bone conduction audiometry relies on transducers with varying properties.
• Current reference equivalent threshold vibratory force levels (RETVFL) in ISO 389-3 are based on limited transducer types (B71, KH70).
• These RETVFL values are applied universally, potentially impacting measurement accuracy.

Purpose of the Study:

• To compare bone conduction hearing thresholds obtained with different transducers.
• To evaluate the consistency of measurements across various frequencies.
• To determine if current RETVFL standards are adequate for all available transducers.

Main Methods:

• A prospective study involving psychometric measurement of hearing thresholds.
• Tested frequencies ranged from 125 Hz to 8000 Hz.
• Utilized three specific bone conduction transducers: Radioear B71, B81, and Präcitronic KH70.

Main Results:

• Significant differences in measured thresholds were observed between transducers at low (125 Hz, 250 Hz) and high (3000 Hz, 4000 Hz, 6000 Hz, 8000 Hz) frequencies.
• Normal hearing participants showed deviations towards lower thresholds with B71 and B81 at 125 Hz and high frequencies.
• Hearing-impaired participants also exhibited significant differences across transducers at tested frequencies.

Conclusions:

• Existing RETVFL values may not be universally applicable across all bone conduction transducers.
• There is a need to re-evaluate and potentially establish specific RETVFL values for individual transducers.
• Accurate audiometric measurements require consideration of transducer-specific characteristics.