Auditory processing of vowels by normal-hearing and hearing-impaired listeners

Area of Science:

• Auditory Perception
• Psychoacoustics
• Hearing Science

Background:

• Masking patterns reveal how sounds interfere with auditory perception.
• Vowel pulsation patterns (VPPs) can reflect the spectral characteristics of complex sounds.
• Understanding auditory processing in hearing impairment is crucial for developing effective interventions.

Purpose of the Study:

• To investigate masking patterns in normal-hearing and hearing-impaired listeners using synthesized vowel maskers.
• To compare vowel pulsation patterns (VPPs) with the acoustic spectra of the maskers.
• To explore the role of suppression effects in nonsimultaneous masking and their absence in cochlear hearing loss.

Main Methods:

• Utilized the pulsation-threshold procedure to obtain masking patterns.
• Presented synthesized vowel maskers (/a/, /ae/) at varying sound pressure levels, alternating with a sinusoidal probe.
• Obtained simultaneous-masking patterns in a normal-hearing listener for comparison.

Main Results:

• Vowel pulsation patterns (VPPs) in normal-hearing listeners mirrored the acoustic spectra of the vowel maskers.
• Hearing-impaired listeners' VPPs and normal-hearing listeners' simultaneous-masking patterns did not preserve the masker spectra's contour.
• Effects of increased masker level were consistent across both listener groups.

Conclusions:

• Nonsimultaneous masking suppression effects, observed in normal-hearing listeners, appear absent in individuals with cochlear hearing loss.
• Upward spread of masking and a masking function with a slope less than 1.0 explain the effects of masker level.
• Auditory processing differences in hearing impairment impact spectral representation during masking.