title: Suprathreshold auditory processing deficits in noise: Effects of hearing loss and age.
abstract: People with sensorineural hearing loss generally suffer from a reduced ability to understand speech in complex acoustic listening situations, particularly when background noise is present. In addition to the loss of audibility, a mixture of suprathreshold processing deficits is possibly involved, like altered basilar membrane compression and related changes, as well as a reduced ability of temporal coding. A series of 6 monaural psychoacoustic experiments at 0.5, 2, and 6 kHz was conducted with 18 subjects, divided equally into groups of young normal-hearing, older normal-hearing and older hearing-impaired listeners, aiming at disentangling the effects of age and hearing loss on psychoacoustic performance in noise. Random frequency modulation detection thresholds (RFMDTs) with a low-rate modulator in wide-band noise, and discrimination of a phase-jittered Schroeder-phase from a random-phase harmonic tone complex are suggested to characterize the individual ability of temporal processing. The outcome was compared to thresholds of pure tones and narrow-band noise, loudness growth functions, auditory filter bandwidths, and tone-in-noise detection thresholds. At 500 Hz, results suggest a contribution of temporal fine structure (TFS) to pure-tone detection thresholds. Significant correlation with auditory thresholds and filter bandwidths indicated an impact of frequency selectivity on TFS usability in wide-band noise. When controlling for the effect of threshold sensitivity, the listener's age significantly correlated with tone-in-noise detection and RFMDTs in noise at 500 Hz, showing that older listeners were particularly affected by background noise at low carrier frequencies.
authors.affiliation: Medizinische Physik and Cluster of Excellence Hearing4all, Universität Oldenburg, D-26111 Oldenburg, Germany. Electronic address: steffen.kortlang@uni-oldenburg.de.
authors.forename: Steffen
authors.initials: S
authors.lastname: Kortlang
authors.affiliation: Medizinische Physik and Cluster of Excellence Hearing4all, Universität Oldenburg, D-26111 Oldenburg, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Mauermann
authors.affiliation: Medizinische Physik and Cluster of Excellence Hearing4all, Universität Oldenburg, D-26111 Oldenburg, Germany.
authors.forename: Stephan D
authors.initials: SD
authors.lastname: Ewert
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001299:Audiometry; D001308:Auditory Perceptual Disorders; D001309:Auditory Threshold; D005260:Female; D006309:Hearing; D006319:Hearing Loss, Sensorineural / Q000503:physiopathology*; D006801:Humans; D008297:Male; D009622:Noise; D010470:Perceptual Masking; D011571:Psychoacoustics; D013067:Speech Perception / Q000502:physiology*
keywords: Age; Hearing loss; Noise; Suprathreshold processing; Temporal fine structure