title: Spectral and binaural loudness summation for hearing-impaired listeners.
abstract: Sensorineural hearing loss typically results in a steepened loudness function and a reduced dynamic range from elevated thresholds to uncomfortably loud levels for narrowband and broadband signals. Restoring narrowband loudness perception for hearing-impaired (HI) listeners can lead to overly loud perception of broadband signals and it is unclear how binaural presentation affects loudness perception in this case. Here, loudness perception quantified by categorical loudness scaling for nine normal-hearing (NH) and ten HI listeners was compared for signals with different bandwidth and different spectral shape in monaural and in binaural conditions. For the HI listeners, frequency- and level-dependent amplification was used to match the narrowband monaural loudness functions of the NH listeners. The average loudness functions for NH and HI listeners showed good agreement for monaural broadband signals. However, HI listeners showed substantially greater loudness for binaural broadband signals than NH listeners: on average a 14.1 dB lower level was required to reach "very loud" (range 30.8 to -3.7 dB). Overall, with narrowband loudness compensation, a given binaural loudness for broadband signals above "medium loud" was reached at systematically lower levels for HI than for NH listeners. Such increased binaural loudness summation was not found for loudness categories below "medium loud" or for narrowband signals. Large individual variations in the increased loudness summation were observed and could not be explained by the audiogram or the narrowband loudness functions.
authors.affiliation: Project Group Hearing, Speech and Audio Technology of the Fraunhofer IDMT and Cluster of Excellence Hearing4all, Oldenburg, Germany; Medizinische Physik and Cluster of Excellence Hearing4all, Universität Oldenburg, 26111 Oldenburg, Germany. Electronic address: dirk.oetting@idmt.fraunhofer.de.
authors.forename: Dirk
authors.initials: D
authors.lastname: Oetting
authors.affiliation: Medizinische Physik and Cluster of Excellence Hearing4all, Universität Oldenburg, 26111 Oldenburg, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Hohmann
authors.affiliation: Project Group Hearing, Speech and Audio Technology of the Fraunhofer IDMT and Cluster of Excellence Hearing4all, Oldenburg, Germany.
authors.forename: Jens-E
authors.initials: JE
authors.lastname: Appell
authors.affiliation: Project Group Hearing, Speech and Audio Technology of the Fraunhofer IDMT and Cluster of Excellence Hearing4all, Oldenburg, Germany; Medizinische Physik and Cluster of Excellence Hearing4all, Universität Oldenburg, 26111 Oldenburg, Germany.
authors.forename: Birger
authors.initials: B
authors.lastname: Kollmeier
authors.affiliation: Medizinische Physik and Cluster of Excellence Hearing4all, Universität Oldenburg, 26111 Oldenburg, Germany.
authors.forename: Stephan D
authors.initials: SD
authors.lastname: Ewert
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D000368:Aged; D000465:Algorithms; D001307:Auditory Perception / Q000502:physiology*; D001309:Auditory Threshold; D005260:Female; D006310:Hearing Aids; D034381:Hearing Loss / Q000503:physiopathology*; D006319:Hearing Loss, Sensorineural / Q000503:physiopathology; D006320:Hearing Tests; D006801:Humans; D008144:Loudness Perception / Q000502:physiology*; D008297:Male; D055815:Young Adult
keywords: Categorical loudness scaling; Diagnosis; Hearing aid fitting; Hearing impairment; Loudness summation; Recruitment