Psychoacoustic consequences of compression in the peripheral auditory system

Area of Science:

• Auditory Neuroscience
• Psychoacoustics
• Nonlinear Dynamics

Background:

• Basilar membrane (BM) responses exhibit compressive nonlinearity at midrange sound levels, particularly near a place's characteristic frequency.
• This nonlinearity is crucial for understanding normal auditory perception and the effects of hearing loss.

Purpose of the Study:

• To demonstrate how basilar membrane compressive nonlinearity explains various auditory phenomena.
• To elucidate how cochlear hearing loss, by linearizing BM responses, alters auditory perception.

Main Methods:

• Theoretical analysis linking basilar membrane nonlinearity to psychoacoustic observations.
• Examination of phenomena such as masking, increment/decrement detection, temporal integration, and complex sound perception.
• Comparison of normal versus impaired cochlear function effects on BM responses.

Main Results:

• Basilar membrane nonlinearity explains excess masking, nonlinear forward masking growth, phase effects in masking, level-dependent detection abilities, and perception of vowellike sounds.
• Cochlear hearing loss leads to more linear BM responses.
• Linearized BM responses account for loudness recruitment, linear masking additivity, linear forward masking growth, and reduced temporal resolution.

Conclusions:

• Basilar membrane compressive nonlinearity is a fundamental mechanism underlying diverse auditory phenomena in normal hearing.
• The linearization of basilar membrane responses in cochlear hearing loss directly explains characteristic perceptual deficits.