Extended high-frequency thresholds in noise-induced hearing loss

Area of Science:

• Audiology
• Occupational Health
• Hearing Science

Background:

• Occupational noise exposure is a significant risk factor for hearing loss.
• Extended high-frequency (EHF) hearing assessment (9-18 kHz) can detect early auditory changes.
• Understanding the interplay between age and noise-induced hearing loss (NIHL) in EHF ranges is crucial.

Purpose of the Study:

• To investigate the presence and characteristics of EHF hearing loss in males with occupational noise exposure.
• To examine the influence of age on EHF hearing thresholds across different grades of conventional NIHL.

Main Methods:

• Audiometric thresholds (air and bone conduction) were measured in conventional frequencies (0.5-8 kHz).
• Air-conduction thresholds were assessed in the extended high-frequency range (9-18 kHz).
• 167 males with occupational noise exposure history were grouped by age and classified by NIHL severity.

Main Results:

• Threshold elevation in the EHF range was observed in all participants, irrespective of age or conventional hearing loss grade.
• An age-related effect on EHF thresholds was only evident in subjects with the mildest grades of conventional NIHL.
• EHF hearing loss is a consistent finding in noise-exposed individuals, with age being a modifying factor in early stages.

Conclusions:

• EHF audiometry is sensitive to occupational noise exposure across all age groups.
• Age plays a role in the progression of EHF hearing loss, particularly in individuals with less severe conventional NIHL.
• Early detection of EHF hearing changes may inform targeted hearing conservation strategies for noise-exposed workers.