Hearing loss can compress loudness range while keeping sharp categories

Evidence

Listener HL11 (4th row) has LDL that is within the ranges of a NH listener; the higher threshold level causes the spacing between category boundary curves to be compressed horizontally. Despite this compression, this listener with HL has well-defined perceptual boundaries between categories (i.e., sharply-sloped boundary curves). — Dijk, Pim van, Physiology, Psychoacoustics and…, 2549

Categorization

• XREF: Shows that reduced dynamic range and loss of perceptual resolution (sharpness) are separable dimensions — relevant to physiological accounts of loudness recruitment in cochlear damage.
• QUESTION: What physiological mechanism allows category boundaries to stay sharp despite the compressed range? Suggests peripheral compression need not degrade categorical resolution.