Evidence for age-related cochlear synaptopathy in humans unconnected to speech-in-noise intelligibility deficits
abstract Cochlear synaptopathy (or the loss of primary auditory synapses) remains a subclinical condition of uncertain prevalence. Here, we investigate whether it affects humans and whether it contributes to suprathreshold speech-in-noise intelligibility deficits. For 94 human listeners with normal...
| Authors: | , , |
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| Format: | article |
| Status: | Published version |
| Publication Date: | 2019 |
| Country: | España |
| Institution: | Universidad de Salamanca (USAL) |
| Repository: | GREDOS. Repositorio Institucional de la Universidad de Salamanca |
| OAI Identifier: | oai:gredos.usal.es:10366/154984 |
| Online Access: | http://hdl.handle.net/10366/154984 |
| Access Level: | Open access |
| Keyword: | Auditory brainstem response Synaptopathy Auditory deafferentation Noise exposure Speech-in-noise Noise Audiometry, Evoked Response 3213.05 Cirugía de Garganta, Nariz y Oídos 2490 Neurociencias |
| Summary: | abstract Cochlear synaptopathy (or the loss of primary auditory synapses) remains a subclinical condition of uncertain prevalence. Here, we investigate whether it affects humans and whether it contributes to suprathreshold speech-in-noise intelligibility deficits. For 94 human listeners with normal audiometry (aged 12e68 years; 64 women), we measured click-evoked auditory brainstem responses (ABRs), self- reported lifetime noise exposure, and speech reception thresholds for sentences (at 65dB SPL) and words (at 50, 65 and 80 dB SPL) in steady-state and fluctuating maskers. Based on animal research, we assumed that the shallower the rate of growth of ABR wave-I amplitude versus level function, the higher the risk of suffering from synaptopathy. We found that wave-I growth rates decreased with increasing age but not with increasing noise exposure. Speech reception thresholds in noise were not correlated with wave-I growth rates and mean speech reception thresholds were not statistically different for two subgroups of participants (N 1⁄4 14) with matched audiograms (up to 12 kHz) but different wave-I growth rates. Altogether, the data are consistent with the existence of age-related but not noise-related syn- aptopathy. In addition, the data dispute the notion that synaptopathy contributes to suprathreshold speech-in-noise intelligibility deficits. |
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