The effect of basilar-membrane nonlinearity on the shapes of masking period patterns in normal and impaired hearing.
Masking period patterns (MPPs) were measured in listeners with normal and impaired hearing using amplitude-modulated tonal maskers and short tonal probes. The frequency of the masker was either the same as the frequency of the probe (on-frequency masking) or was one octave below the frequency of the probe (off-frequency masking). In experiment 1, MPPs were measured for listeners with normal hearing using different masker levels. Carrier frequencies of 3 and 6 kHz were used for the masker. The probe had a frequency of 6 kHz. For all masker levels, the off-frequency MPPs exhibited deeper and longer valleys compared with the on-frequency MPPs. Hearing-impaired listeners were tested in experiment 2. For some hearing-impaired subjects, masker frequencies of 1.5 kHz and 3 kHz were paired with a probe frequency of 3 kHz. MPPs measured for listeners with hearing loss had similar shapes for on- and off-frequency maskers. It was hypothesized that the shapes of MPPs reflect nonlinear processing at the level of the basilar membrane in normal hearing and more linear processing in impaired hearing. A model assuming different cochlear gains for normal versus impaired hearing and similar parameters of the temporal integrator for both groups of listeners successfully predicted the MPPs.
Wojtczak
M
M
Clinical Psychoacoustics Laboratory, University of Minnesota, Minneapolis 55455, USA. wojtc001@tc.umn.edu
Schroder
A C
AC
Kong
Y Y
YY
Nelson
D A
DA
D001307:Auditory Perception / Q000502:physiology*; D001309:Auditory Threshold / Q000502:physiology; D001489:Basilar Membrane / Q000502:physiology*; D006309:Hearing / Q000502:physiology*; D006316:Hearing Loss, High-Frequency / Q000175:diagnosis*; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis*; D006801:Humans; D008954:Models, Biological; D010470:Perceptual Masking; D013997:Time Factors