Excess masking among listeners with a sensorineural hearing loss

Area of Science:

• Audiology
• Psychoacoustics
• Sensorineural Hearing Loss

Background:

• Sensorineural hearing loss can affect frequency selectivity.
• Upward spread of masking is a phenomenon where a masker at one frequency raises the hearing threshold at higher frequencies.
• Quantifying excess masking in hearing-impaired listeners is crucial for understanding auditory processing deficits.

Purpose of the Study:

• To investigate whether individuals with sensorineural hearing loss exhibit increased upward spread of masking compared to normal-hearing listeners.
• To quantify the extent of this excess masking in relation to hearing thresholds in quiet.

Main Methods:

• Three experiments were conducted using hearing-impaired listeners with varying degrees of sensorineural hearing loss.
• Masked thresholds were measured at test frequencies between 500-3000 Hz.
• Excess masking was calculated by comparing actual masked thresholds to expected thresholds derived from thresholds in quiet and normal-hearing listener data.

Main Results:

• Hearing-impaired listeners demonstrated significant excess masking, ranging from 12-15 dB.
• Maximum excess masking occurred when the listener's threshold in quiet matched the average normal masked threshold.
• This excess masking was observed at frequencies above the masker frequency.

Conclusions:

• Listeners with sensorineural hearing loss exhibit abnormal upward spread of masking.
• This finding indicates reduced frequency selectivity in hearing-impaired individuals, even when considering their baseline hearing levels.
• The results highlight a specific auditory processing deficit contributing to communication difficulties in sensorineural hearing loss.