Loss of auditory sensitivity from inner hair cell synaptopathy can be centrally compensated in the young but not old brain

NEUROBIOLOGY OF AGING

卷:44

Article

Moehrle, Dorit¹  Ni, Kun^1,2  Varakina, Ksenya¹  Bing, Dan¹  Lee, Sze Chim¹  Zimmermann, Ulrike¹  Knipper, Marlies¹  Ruettiger, Lukas¹ 

[1] Univ Tubingen, Dept Otolaryngol Head & Neck Surg, Tubingen Hearing Res Ctr, Mol Physiol Hearing, D-72076 Tubingen, Germany

[2] Shanghai Jiao Tong Univ, Dept Otolaryngol Head & Neck Surg, Shanghai Childrens Hosp, Shanghai 200030, Peoples R China

关键词: Age-related hearing loss;    Presbycusis;    Inner hair cell synaptopathy;    Central compensation;   

DOI  :  10.1016/j.neurobiolaging.2016.05.001

来源: Elsevier

【 摘 要 】

A dramatic shift in societal demographics will lead to rapid growth in the number of older people with hearing deficits. Poorer performance in suprathreshold speech understanding and temporal processing with age has been previously linked with progressing inner hair cell (IHC) synaptopathy that precedes age-dependent elevation of auditory thresholds. We compared central sound responsiveness after acoustic trauma in young, middle-aged, and older rats. We demonstrate that IHC synaptopathy progresses from middle age onward and hearing threshold becomes elevated from old age onward. Interestingly, middle-aged animals could centrally compensate for the loss of auditory fiber activity through an increase in late auditory brainstem responses (late auditory brainstem response wave) linked to shortening of central response latencies. In contrast, old animals failed to restore central responsiveness, which correlated with reduced temporal resolution in responding to amplitude changes. These findings may suggest that cochlear IHC synaptopathy with age does not necessarily induce temporal auditory coding deficits, as long as the capacity to generate neuronal gain maintains normal sound-induced central amplitudes. (C) 2016 The Authors. Published by Elsevier Inc.

【 授权许可】

Free