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A Compression System within the Cochlea

Listserve Members,
An implied or stated goal of some hearing aid processing strategies is to compensate for the lost compressive function of the cochlea resulting from sensorineural hearing loss. I am in the process of writing a brief paper (as part of my doctoral coursework) discussing the ability of current devices to actually do this and the pros and cons of even attempting to do so. Initially, I am trying to describe the "compression parameters" of the normal cochlea. I have found substantial physiologic work in various animals suggesting linear function below an initial "compression threshold" of about 20-40 dB SPL and some psychophysical work in humans suggesting an initial "compression threshold"  of 20 dB SPL or less. For midlevel inputs (40-90 to 110 dB SPL or so) a compression ratio of about 5:1 (7:1 to 3:1) has been suggested. For high levels (above 90 to 110 dB) some research suggests linear functioning but I am unclear on which references support this idea. I have not found any references that discuss potential "time constants" for the normal cochlea. I believe some physiologic work on outer hair cells has suggested they can function essentially instantaneously.
In short, I am interested in references that may discuss the compressive nonlinearity of the cochlea in terms of "compression characteristics". In specific, references for a second high level compression threshold and a discussion of "cochlear time constants". Any thoughts or ideas are appreciated.
Ben Hornsby