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Effect of cochlear damage on the detection of complex temporal envelopes
Christian Füllgrabe1, Bernard Meyer, Christian Lorenzi
1Equipe Perception Auditive, Laboratoire de Psychologie Expérimentale - UMR CNRS 8581, Institut de Psychologie, Université René Descartes - Paris 5, 71 Avenue Vaillant, 92774, Boulogne-Billancourt, France. christian.fullgrabe@psycho.univ-paris5.fr
Hearing Research
|April 10, 2003
Summary
Hearing-impaired listeners show normal complex temporal envelope perception, indicating central non-linearity is key. Cochlear damage does not affect this auditory processing ability.
Area of Science:
- Auditory Neuroscience
- Psychoacoustics
- Hearing Science
Background:
- Complex temporal envelope perception relies on distortion components from peripheral or central non-linearities.
- Understanding the origin of these non-linearities is crucial for diagnosing hearing impairments.
Purpose of the Study:
- To investigate whether cochlear damage affects the detection of complex temporal envelopes.
- To determine if the non-linearity involved in temporal envelope perception is peripheral (cochlear) or central (post-cochlear).
Main Methods:
- Measured first- and second-order amplitude modulation (AM) detection thresholds in normally hearing (NH) and hearing-impaired (HI) listeners.
- Used a 2-kHz pure-tone carrier and varied AM rates (fm: 4-87 Hz; fm': 4-23 Hz).
- Equated detectability and audibility between NH and HI groups to isolate effects of non-linearity.
Main Results:
- First-order AM detection thresholds were normal or better-than-normal in HI listeners at specific rates.
- Second-order AM detection thresholds were identical in both NH and HI listeners across all tested rates.
- Results remained consistent when audibility was equated, not just detectability.
Conclusions:
- Cochlear damage does not impair the detection of complex temporal envelopes.
- The distortion component crucial for temporal envelope perception originates from central non-linearities, not cochlear processes like compression or transduction.