High-frequency audiometry. Masking of air- and bone-conduction signals

Area of Science:

• Audiology
• Hearing Science
• Signal Processing

Background:

• Interaural attenuation is crucial for accurate hearing assessments, especially in higher frequencies.
• Understanding bone-conduction masking is vital for diagnosing hearing loss.
• Previous research has limitations in high-frequency bone-conduction assessment.

Purpose of the Study:

• To investigate interaural attenuation for air- and bone-conduction signals across extended frequency ranges.
• To establish minimum masking levels for bone-conduction signals in the high-frequency range (8-16 kHz).
• To provide recommendations for effective high-frequency bone-conduction masking procedures.

Main Methods:

• Measured interaural attenuation for air-conduction (0.25-18 kHz) and bone-conduction (0.25-16 kHz) signals.
• Utilized ear canal occlusion with Koss HV/1A earphones for bone-conduction masking to mitigate acoustic transmission.
• Determined minimum masking levels using 1/3-octave filtered white noise for bone-conduction signals (8-16 kHz).

Main Results:

• Acoustic transmission through the headset necessitates ear canal occlusion for high-frequency bone-conduction masking.
• Minimum masking levels for bone-conduction signals were established between 8-16 kHz.
• Central masking levels were comparable across conventional and high frequencies.
• Cross-masking levels decreased by approximately 10-15 dB above 6 kHz.

Conclusions:

• Ear canal occlusion is essential for accurate high-frequency bone-conduction masking.
• Specific masking level data for high-frequency bone-conduction is now available.
• The findings support the development of improved masking strategies for high-frequency audiometry.