Varnet Léo, Léger Agnès C, Boucher Sophie, Bonnet Crystel, Petit Christine, Lorenzi Christian
Laboratoire des Systèmes Perceptifs, UMR CNRS 8248, Département d'Études Cognitives, École normale supérieure, Université Paris Sciences & Lettres, Paris, France.
Manchester Centre for Audiology and Deafness, Division of Human Communication, Development & Hearing, School of Health Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom.
Front Aging Neurosci. 2021 Mar 1;13:640522. doi: 10.3389/fnagi.2021.640522. eCollection 2021.
The decline of speech intelligibility in presbycusis can be regarded as resulting from the combined contribution of two main groups of factors: (1) audibility-related factors and (2) age-related factors. In particular, there is now an abundant scientific literature on the crucial role of suprathreshold auditory abilities and cognitive functions, which have been found to decline with age even in the absence of audiometric hearing loss. However, researchers investigating the direct effect of aging in presbycusis have to deal with the methodological issue that age and peripheral hearing loss covary to a large extent. In the present study, we analyzed a dataset of consonant-identification scores measured in quiet and in noise for a large cohort ( = 459, age = 42-92) of hearing-impaired (HI) and normal-hearing (NH) listeners. HI listeners were provided with a frequency-dependent amplification adjusted to their audiometric profile. Their scores in the two conditions were predicted from their pure-tone average (PTA) and age, as well as from their Extended Speech Intelligibility Index (ESII), a measure of the impact of audibility loss on speech intelligibility. We relied on a causal-inference approach combined with Bayesian modeling to disentangle the direct causal effects of age and audibility on intelligibility from the indirect effect of age on hearing loss. The analysis revealed that the direct effect of PTA on HI intelligibility scores was 5 times higher than the effect of age. This overwhelming effect of PTA was not due to a residual audibility loss despite amplification, as confirmed by a ESII-based model. More plausibly, the marginal role of age could be a consequence of the relatively little cognitively-demanding task used in this study. Furthermore, the amount of variance in intelligibility scores was smaller for NH than HI listeners, even after accounting for age and audibility, reflecting the presence of additional suprathreshold deficits in the latter group. Although the non-sense-syllable materials and the particular amplification settings used in this study potentially restrict the generalization of the findings, we think that these promising results call for a wider use of causal-inference analysis in audiology, e.g., as a way to disentangle the influence of the various cognitive factors and suprathreshold deficits associated to presbycusis.
（1）与可听度相关的因素和（2）与年龄相关的因素。具体而言，目前有大量科学文献阐述了阈上听觉能力和认知功能的关键作用，研究发现即使在没有听力计检测到听力损失的情况下，这些能力也会随着年龄增长而下降。然而，研究老年聋中衰老直接影响的研究人员必须应对一个方法学问题，即年龄和外周听力损失在很大程度上是共同变化的。在本研究中，我们分析了一个数据集，该数据集包含了一大群（n = 459，年龄42 - 92岁）听力受损（HI）和听力正常（NH）的听众在安静和噪声环境下的辅音识别分数。为HI听众提供了根据其听力计检测结果进行频率依赖调整的放大装置。根据他们的纯音平均听阈（PTA）、年龄以及扩展言语清晰度指数（ESII，一种衡量可听度损失对言语清晰度影响的指标）预测他们在两种环境下的分数。我们采用因果推断方法并结合贝叶斯建模，以区分年龄和可听度对清晰度的直接因果效应与年龄对听力损失的间接效应。分析表明，PTA对HI清晰度分数的直接影响比年龄的影响高5倍。正如基于ESII的模型所证实的，尽管有放大装置，PTA的这种压倒性影响并非由于残余的可听度损失。更合理的解释是，年龄的边际作用可能是本研究中使用的认知要求相对较低的任务导致的。此外，即使在考虑了年龄和可听度之后，NH听众清晰度分数的方差量仍小于HI听众，这反映出后一组存在额外的阈上缺陷。尽管本研究中使用的无意义音节材料和特定的放大设置可能会限制研究结果的推广，但我们认为这些有前景的结果呼吁在听力学中更广泛地使用因果推断分析，例如，作为一种区分与老年聋相关的各种认知因素和阈上缺陷影响的方法。
