Masking and partial masking in listeners with a high-frequency hearing loss

Area of Science:

• Audiology
• Psychoacoustics
• Hearing Science

Background:

• Sensorineural hearing loss (SNHL) affects individuals across a spectrum of severity.
• Understanding auditory perception under masking is crucial for diagnosing and managing hearing impairments.
• Previous research indicates challenges in speech understanding in noise for those with SNHL.

Purpose of the Study:

• To investigate the impact of masking on auditory thresholds in individuals with moderate to moderate-severe SNHL.
• To compare masked thresholds in regions of impaired hearing versus regions with near-normal hearing.
• To explore the dynamic range of hearing under masking conditions for hearing-impaired listeners.

Main Methods:

• Three listeners with SNHL participated in two masking and one partial masking experiment.
• Masking experiments used specific frequencies (fM) and levels (LM) of masker tones.
• Partial masking experiments assessed auditory functions with varying probe tone levels under masking.

Main Results:

• Elevated masked thresholds were observed in SNHL listeners, affecting both impaired and near-normal hearing regions.
• The elevation in masked thresholds in near-normal regions mirrored the elevation in absolute thresholds.
• Partial masking functions were similar between SNHL and normal-hearing listeners, but at higher probe tone levels for SNHL listeners.

Conclusions:

• Higher masked thresholds in SNHL listeners significantly reduce the dynamic range of hearing, particularly in the presence of masking.
• This reduced dynamic range in both impaired and mildly impaired hearing regions may underlie speech perception deficits in noisy environments.
• The findings highlight the complex impact of SNHL on auditory perception beyond absolute threshold measurements.