Loss of cochlear compression most harms speech recognition of intensity-attenuated syllables

Evidence

This paper reports an experiment performed to reveal the effects of a loss of compression on the recognition of syllables presented with fluctuating level. The procedure involves using a filterbank with dynamic compression to simulate hearing impairment in normal hearing listeners. The results indicate that, when the compression of normal hearing has been cancelled, it is difficult to hear syllables at low sound levels when they are sandwiched between syllables with higher levels. The hearing losses observed in patients will commonly involve multiple auditory problems and they will interact in complicated ways that make it difficult to distinguished the effects of any one component of auditory processing. The HI simulator shows how a single factor can be isolated using an auditory model, provided the model is sufficiently detailed. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4093

The HI simulator can counteract the cochlear compression in normal hearing (NH) listeners and, thereby, isolate the deficit associated with a loss of compression in speech perception. … The results show that the loss of compression has its largest effect on recognition when the second syllable is attenuated relative to the first and third syllables. This is probably because the internal level of the second syllable is attenuated proportionately more when there is a loss of compression. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4043

Categorization

• QUESTION: What is the cochlear compression mechanism being cancelled here — outer hair cell function producing the compressive nonlinearity? Worth chasing the underlying physiology.
• XREF: Directly relevant to the reader’s whole-book project of understanding hearing physiology and perception; the cochlear compression mechanism it’s isolating connects to other chapters on cochlear nonlinearity.
• corroborated: 2 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 4093; Dijk, Pim van, Physiology, Psychoacoustics and…, 4043