Which hearing impairment influences: our gender, our age, our place of life? To answer this question, a Toulouse team carried out a large study with 450 people from 13 different populations. And age is not the most decisive factor …
A study in published in Scientific reports from the Nature magazine is interested in hearing sensitivity. Gender, environment, age, what does the perception of noises in humans affect? Patricia Balaresque, CNRS researcher at Biodiversity research center and environment (CRBE) in ToulouseGives light on a study that is carried out for 4 years.
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Why is this hearing study important?
Listening is one of the least examined senses from an evolutionary point of view. Medicine is interested, but especially for people with hearing problems, often in population groups of European ancestors. In many countries, we lack information about the characteristics of a healthy hearing in order to understand why and how hearing develops and deteriorates. Our project aims to take into account other factors than medically, in particular organic and ecological consideration.
How did you work with which populations?
We have examined the hearing of 450 people under 13 population groups of five countries around the world (Gabon, Uzbekistan, South Africa, united kingdom and equator) and in contrast environments. Höhenhöhe, steppes, forests and of course the levels, the main lives of the world, differentiate rural and urban environments. We have also taken into account factors such as age, gender and laterality (each one has a LeKohr). For the first time it was the idea of having all of these factors together without a priori on one of them. We used transient acoustic oto emissions: a probe sends noises between 0 and 6000 Hz in the ear, which then reacts to these stimuli. This enables us to reconstruct the sensitivity curve of each individual and to uncover the differences in the difference.
“Between 18 and 55 we lose 2.5 decibels”
What are the main results of the study?
The factor that explains most differences in the listening between individuals is sex with a remarkable difference between 2 dB between men and women in the entire frequency range. In contrast to certain stereotypes, this difference is not limited to certain frequencies, but extends over the whole … No, women do not listen to the frequency of the screaming of babies! This difference cannot be explained at the moment. In fact, there is the traces of cochlea morphology, but it doesn’t explain everything. Other studies indicate another in the utero exposure associated with hormones.
What about the environment?
The environment also plays a crucial role, it is the second factor before age. The most sensitive hearing profiles are in the forest environments, possibly because individuals receive a lot of information and they are important to you or because the hearing is preserved (less noise, pollution, lower consumption of certain drugs). Conversely, we hear less strongly at high heights. Perhaps because of the pressure because the ear is very exposed, protects itself directly, but that cannot explain everything. The city’s hearing is somewhat countless compared to the middle and high frequencies. This trend is observed in birds, which stood up for higher frequencies in the city to stand out from background noise.
How does age come from?
It is gradually. We start losing 0.5 decibels (DB) between 35 and 45 years between 25 and 35 years. We have already lost 1 dB and between 45 and 55 years. We lost 2.5 compared to 18 years. From the point of view of hearing protection in life, it is interesting that the idea would be to pursue a long -term approach and not to say that I will suddenly consult for 60 years. Listening to lifestyle should be set up at a young age.
“The green areas of the green in the city enable them to break the sound dynamics and thus reduce the overall stress.”
How do these results influence our hearing understanding?
This indicates that our approaches to the health of hearing must be adapted according to the living environments of individuals and their own biological characteristics (gender, age). The integration of this knowledge could not only avoid excessive inquiries in women that cause fatigue and stress, but also protect the hearing of men and children in the cinema.
What are the broader effects of these discoveries?
With regard to public health, the adaptation of hearing aids and work environments to the audio specificities of individuals could help reduce stress and improve the quality of life. In urban planning, the protection of natural spaces and thinking about the global development of cities, especially the sound, would better preserve human hearing. Green islands that are required to preserve biological diversity can also be places where sound dynamics can be broken and the overall stress lower.