Balaresque Patricia, Delmotte Sébastien, Delehelle Franklin, Moreira Andreia, Saenz-Oyhéréguy Nancy, Croze Myriam, Hegay Tatyana, Aripova Tamara, Le Bomin Sylvie, Mennecier Philippe, Descouens Didier, Cussat-Blanc Sylvain, Luga Hervé, Guevara Angel, D'Amato Maria Eugenia, King Turi, Mollereau Catherine, Heyer Evelyne
Centre de Recherche sur la Biodiversité et l'Environnement (CRBE) UMR5300, CNRS, Université de Toulouse, IRD, Université Paul Sabatier, 118 Route de Narbonne, Bâtiment 4R1, 31062, Toulouse, France.
MAD-Environnement, Nailloux, France.
Sci Rep. 2025 Mar 26;15(1):10475. doi: 10.1038/s41598-025-92763-6.
Hearing remains an underexplored aspect of human evolution. While the growing prevalence of hearing issues worldwide highlights the need to investigate factors beyond age, ototoxic substances, and recreational noise- factors affecting only a subset of the population -the role of environmental influences remains relatively unaddressed. In contrast, hearing and vocalizations have been extensively studied in many vertebrates through the Acoustic Adaptation Hypothesis, which suggests that acoustic communication adapts to the structure of the immediate environment. To explore how the environment shapes the ear's ability to process sound, studying the cochlea is essential since it is responsible for capturing, amplifying, and converting sound waves into electrical signals. Cochlear sensitivity can be measured using Transient-Evoked Otoacoustic Emissions (TEOAE), which assess the cochlea's ability to produce and transmit an acoustic response after sound stimulation. By analyzing TEOAE profiles, we gain valuable insights into how the cochlea responds to external auditory stimuli. We evaluated the influence of both endogenous (age, sex, ear side) and exogenous factors (ethnicity, environment, language) on cochlear sensitivity by collecting TEOAE data from 448 healthy individuals across 13 global populations in Ecuador, England, Gabon, South Africa, and Uzbekistan, living in diverse environments. For each individual, we derived six acoustic metrics from these TEOAE profiles to characterize the amplitude and frequency spectrum of cochlear sensitivity. Our results show that amplitude is primarily influenced by sex (up to 2 dB) and environment (up to 3.6 dB), followed by age and ear side. The frequency spectrum is determined exclusively by exogenous factors, with environment- particularly altitude, and urban versus rural settings -being the most significant. These findings challenge existing assumptions and highlight the need to consider both biological and environmental factors when studying auditory processes.
听力仍然是人类进化中一个未被充分探索的方面。虽然全球听力问题的日益普遍凸显了研究年龄、耳毒性物质和娱乐性噪音之外的因素的必要性（这些因素仅影响一部分人群），但环境影响的作用仍相对未得到探讨。相比之下，通过声学适应假说，在许多脊椎动物中对听力和发声进行了广泛研究，该假说认为声学通讯会适应周围环境的结构。为了探究环境如何塑造耳朵处理声音的能力，研究耳蜗至关重要，因为它负责捕捉、放大并将声波转换为电信号。可以使用瞬态诱发耳声发射（TEOAE）来测量耳蜗灵敏度，TEOAE可评估耳蜗在声音刺激后产生和传输声学反应的能力。通过分析TEOAE图谱，我们能够深入了解耳蜗对外界听觉刺激的反应。我们从厄瓜多尔、英国、加蓬、南非和乌兹别克斯坦的13个全球人群中的448名健康个体收集TEOAE数据，这些个体生活在不同环境中，以此评估内源性因素（年龄、性别、耳朵侧别）和外源性因素（种族、环境、语言）对耳蜗灵敏度的影响。对于每个个体，我们从这些TEOAE图谱中得出六个声学指标，以表征耳蜗灵敏度的幅度和频谱。我们的结果表明，幅度主要受性别（高达2分贝）和环境（高达3.6分贝）影响，其次是年龄和耳朵侧别。频谱完全由外源性因素决定，其中环境——尤其是海拔高度以及城市与农村环境——最为显著。这些发现挑战了现有假设，并强调在研究听觉过程时需要同时考虑生物和环境因素。
