Extended high-frequency audiometry. Air- and bone-conduction thresholds, age and gender variations

Area of Science:

• Audiology
• Hearing Science
• Gerontology

Background:

• Hearing thresholds are typically assessed within conventional audiometric ranges.
• Extended high-frequency hearing (up to 16-18 kHz) is less studied but crucial for understanding age-related changes.
• Normative data for bone-conduction in extended high frequencies are limited.

Purpose of the Study:

• To establish normative air- and bone-conduction hearing thresholds in healthy individuals across a wide age range (8-80 years).
• To investigate the influence of age and frequency on hearing thresholds, particularly in the extended high-frequency range (8-16 kHz).
• To identify gender-specific differences in extended high-frequency hearing thresholds.

Main Methods:

• Audiometric testing including conventional and extended high frequencies (up to 18 kHz for air-conduction, 16 kHz for bone-conduction).
• Inclusion of otologically healthy subjects across diverse age groups (8-14 years to 80+ years).
• Statistical analysis to determine age- and gender-specific thresholds, medians, and ranges, referencing ISO 7029 (1984) for conventional frequencies.

Main Results:

• Conventional air-conduction thresholds were excellent (< or = 10 dB HL) in subjects under 30, aligning with ISO standards for older groups.
• Extended high-frequency bone-conduction thresholds (8-16 kHz) increased with both age and frequency.
• A slight, generally non-significant, trend for higher thresholds in males was observed. Hearing deterioration at high frequencies was evident even in young adults (18-24 years).

Conclusions:

• Age is a significant factor in hearing threshold changes, especially at extended high frequencies.
• Early signs of high-frequency hearing loss can be detected in young adulthood.
• The study provides valuable normative data for extended high-frequency bone conduction, aiding in the early detection of hearing impairments.