A hearing impairment simulator can isolate cochlear compression loss in normal-hearing listeners

Evidence

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. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4043

The HI simulator is essentially a high-fidelity synthesizer based on the dynamic, compressive gammachirp filter bank (dcGC-FB) (Irino and Patterson 2006 ). It analyses naturally recorded speech sounds with a model of the auditory periphery that includes fast-acting compression and then resynthesizes the sounds in a form that counteracts the compression in a NH listener. They hear speech with little distortion or background noise (Irino et al. 2013 ) but without their normal compression. This makes it possible to investigate recruitment phenomenon that are closely related to loss of cochlear compression (Bacon et al. 2004 ) using NH listeners who have no other auditory problems. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4048

The HI simulator is used to adjust syllable level to simulate the hearing of 80 year old listeners with “normal” presbycusis (80 year 100 %) or a complete loss of compression (80 year 0 %). — Dijk, Pim van, Physiology, Psychoacoustics and…, 4049

The stimuli were generated in two stages: First, three-syllable nonsense words were composed from the recordings of a male speaker, identified as “MIS” (FW03) in a speech sound database (Amano et al. 2006 ), and adjusted in level to produce the dip and constant conditions of the experiment. Second, the HI simulator was used to modify the stimuli to simulate the hearing of two 80 year old listeners, one with average hearing for an 80 year old and one with a complete loss of compression. There was also a normal-hearing control condition in which the level was reduced a fixed 30 dB. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4054

To realize the 80 year 100 % condition, the output level of each channel was decreased until the audiogram of the dcGC-FB (normal hearing) matched the average audiogram of an 80 year old. To realize the 80 year 0 % condition, an audiogram was derived with the dcGC-FB having no compression whatsoever, and then the output level of each channel was decreased until the audiogram matched the audiogram of an average 80 year old. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4077

The HI simulator is used to adjust syllable level to simulate the hearing of 80 year old listeners with “normal” presbycusis (80 year 100 %) or a complete loss of compression (80 year 0 %). — Dijk, Pim van, Physiology, Psychoacoustics and…, 4049

Categorization

• DEFINE: Explains how the HI simulator functions as an experimental isolation tool rather than a simple amplification device.
• QUESTION: Does a ‘100% compression’ simulation of an average 80 year old represent genuine presbycusis, and how valid is the 0% compression condition as a pure loss-of-compression model?
• XREF: Connects to the broader literature on hearing-loss simulation used in the author’s research programme on compression and perception. — connects to: Real-time auditory models enable speech recognition, sound reproduction, and hearing aids — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1564; A filter-bank simulator lets normal-hearing listeners experience controlled hearing-impaired states; Model-based impairment simulation isolates specific cochlear processing components (+3 more)
• corroborated: 9 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 4043; Dijk, Pim van, Physiology, Psychoacoustics and…, 4048; Dijk, Pim van, Physiology, Psychoacoustics and…, 4049 (+2 more)

Broader Connections

• Model-based impairment simulation isolates specific cochlear processing components #expands (0.95)
• Differential metrics can separate cochlear gain loss from temporal coding deficits in hearing loss #corroborates (0.82) — Dijk, Pim van, Physiology, Psychoacoustics and…, 5870
• Quiet-versus-narrowband-masked AM threshold differences can isolate temporal coding from cochlear compression #corroborates (0.80)