Cochlear hearing loss spares amplitude modulation detection but distorts perceived fluctuation depth

Evidence

Provided that the carrier is fully audible, the ability to detect amplitude modulation is generally not adversely affected by cochlear hearing loss and may sometimes be better than normal, depending on whether the comparison is made at equal sound pressure level or equal sensation level (Bacon and Viemeister 1985 ; Bacon and Gleitman 1992 ; Moore et al. 1992 ; Moore and Glasberg 2001 ). When the modulation is clearly audible, a sound with a fixed modulation depth appears to fluctuate more for an impaired ear than for a normal ear, probably because of the effects of loudness recruitment (Moore et al. 1996 ). — Dijk, Pim van, Physiology, Psychoacoustics and…, 816

Categorization

• XREF: The loudness-recruitment mechanism that amplifies perceived modulation connects to the cochlear gain/compression physiology covered in earlier chapters. — connects to: The ear’s just-noticeable amplitude difference depends on signal type, level, and frequency — David Howard, Jamie Angus, coustics and Psychoacoustics, 636
• QUESTION: Why would loudness recruitment make a fixed modulation depth fluctuate MORE rather than simply sound louder overall? Mechanism worth chasing.
• corroborated: 3 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 816