Introduction

This part introduction presents an overview of the key concepts discussed in the subsequent chapters. The part describes efforts to model the abnormal growth of loudness and relate it to other perceptual phenomena, such as loudness summation and intensity discrimination. It suggests that the effects of different types of high-frequency sensorineural loss on the growth of loudness for pure tones can be predicted by a model of loudness summation that has previously been applied to noise-induced hearing loss. The part argues that loudness may actually grow less rapidly with intensity in listeners with sensorineural hearing loss than in listeners with normal hearing, even though their loudness-matching functions have exponents greater than unity. It considers extensions of the “proportional just-noticeable difference theory” developed by R. R. Riesz. The part explores perturbational techniques to evaluate how listeners accomplish intensity discrimination for complex stimuli.