Lost cochlear compression degrades speech formant coding in hearing-impaired listeners

Evidence

Specifically, we describe an experiment designed to examine how the loss of cochlear compression affects the recognition of relatively soft syllables occurring in the presence of louder, flanking syllables of varying levels. The aim is to reveal the role of cochlear compression in multi-speaker environments or those with disruptive background noise. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4046 (#expands, via linked claim)

It is assumed that forward masking occurs during auditory neural processing, and that it operates on peripheral auditory output (i.e. neural firing in the auditory nerve). Since the compression component of the peripheral processing is normal in both the 80 year 100 % condition and the NH ‑30 dB condition, the level difference between syllable 2 and syllables 1 and 3 should be comparable in the peripheral output of any specific condition. In this case, ΔSRT provides a measure of the more central masking that occurs during neural processing. When the compression is cancelled, the level difference in the peripheral output for syllable 2 is greater in the dip conditions. If the central masking is constant, independent of the auditory representation, the reduction of the output level for syllable 2 should be reflected in the amount of masking, i.e. ΔSRT. This is like the description of the growth of masking by Moore ( 2012 ), where the growth of masking in a compressive system is observed to be slower than in a non-compressive system. Moore was describing experiments where both the signal and the masker were isolated sinusoids. The results of the current study show that the effect generalizes to speech perception where both the target and the interference are broadband, time-vary sounds. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4089 (#corroborates, via linked claim)

Categorization

• corroborated: 2 independent passages support this claim
• XREF: connects to: Faster-fluctuating sounds trigger less cochlear compression, trading sensitivity for better dynamic encoding — Dijk, Pim van, Physiology, Psychoacoustics and…, 3637; Cochlear suppression is essential for coding complex sounds but poorly characterized in hearing loss; Loss of cochlear compression alone impairs hearing soft syllables amid louder ones — Dijk, Pim van, Physiology, Psychoacoustics and…, 4046 (+7 more)

Broader Connections

• Loss of cochlear compression alone impairs hearing soft syllables amid louder ones #expands (0.90) — Dijk, Pim van, Physiology, Psychoacoustics and…, 4046
• Loss of peripheral compression alone impairs recognition of low-level syllables between louder ones #expands (0.88)
• Masking grows slower in compressive than non-compressive auditory systems, generalizing to speech #corroborates (0.80) — Dijk, Pim van, Physiology, Psychoacoustics and…, 4089
• Hearing loss reduces cochlear suppression and compressive nonlinearity together #qualifies (0.78) — Dijk, Pim van, Physiology, Psychoacoustics and…, 3878
• Quiet-versus-narrowband-masked AM threshold differences can isolate temporal coding from cochlear compression #complicates (0.75)
• Differential metrics can separate cochlear gain loss from temporal coding deficits in hearing loss #expands (0.75) — Dijk, Pim van, Physiology, Psychoacoustics and…, 5870
• Sensorineural hearing loss compresses the full loudness range into fewer decibels #expands (0.70) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 838