Have you ever heard a beep after a big concert? We explain the cause.
The ear is a very delicate sensory organ. Partial hearing loss, also called hearing loss, is common, especially in the elderly, but there are factors that can accelerate it dramatically.
In this article we will talk about one of these factors: acoustic trauma .
structure of the ear
Before starting to explain acoustic trauma, let’s put the problem in context. In the inner ear, particularly in the so-called organ of Corti, there are specialized cells of our sensory system.
These specialized cells have cilia, or small elongations of their cell membrane, which allow them to detect variations in the pressure of the environment (the result of vibrations transmitted in the air) and transform this information into nerve impulses that our brain translates into the sound that we hear.
These hair cells of the organ of Corti do not regenerate, so as we lose them we will not recover hearing capacity over time . The lack of regenerative capacity of this part of the ear is to blame for our hearing getting worse with age and there is currently research looking for ways to regenerate these cells to prevent hearing loss.
This process is called mechanotransduction.
Acoustic trauma: what is it and what types are there?
When we are exposed to very strong vibrations or sounds, such as explosions, gunshots or even music, this can cause damage to our hearing, which will vary depending on the type and intensity of the stimulus. We can differentiate four types of acoustic trauma .
1. Barotrauma
Caused by strong and sudden pressure changes, which mainly affect the eardrum (membrane that protects the rest of the ear). We can experience them when traveling by plane or diving.
These barotraumas can cause symptoms such as a perforated eardrum, moderate hearing loss, ear pain, and tinnitus (also known as tinnitus, a high-pitched, persistent sound). This type of acoustic trauma usually resolves itself over time, but in severe cases it can cause permanent damage to our hearing structure.
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2. Shock wave trauma
These injuries cause injuries to the middle and inner ear and occur from close exposure to explosions or gunshots, where the expanding force of the shock wave travels faster than the speed of sound. Those most affected by this type of trauma are military personnel and people in war zones.
In this type of trauma we will also observe hearing loss, ear pain, tinnitus, vertigo and atrial bleeding, if the eardrum has been perforated (which occurs when we are exposed to sounds greater than 180 decibels). In case the perforated eardrum does not regenerate on its own, a tympanoplasty, surgery to restore the eardrum, will be necessary.
3. Acute sound trauma
These injuries occur when we are exposed to loud sounds, for example those above 130 decibels, for a period of time greater than 30 minutes. The symptoms are ear pain, hearing loss, and in some cases, painful hyperacusis.
Painful hyperacusis manifests itself by making the usual sounds of our day to day seem unbearable and cause us pain. Depending on the damage caused and the age of the patient, the symptoms will disappear or not. In these cases, the tinnitus may be permanent.
4. Chronic sound trauma
Acoustic trauma caused by continuous exposure to sounds above 80 decibels, as would be the case, for example, of construction workers who do not use adequate hearing protection or people who frequently use headphones with music that is too loud.
In this category, the symptoms and their severity will vary according to multiple factors, such as the type of sound (high-pitched sounds are more traumatic), the age of the person affected, and the time and frequency of exposure. It occurs because the hair cells are constantly in the process of mechanotransduction and by not resting enough, they end up producing too many toxic products, causing inflammation that ends up killing them.
This type of acoustic trauma causes tinnitus that disappears after rest and hearing loss. Both tinnitus and hearing loss will worsen with continued exposure, eventually becoming irreversible .
common causes
In the causes of acoustic trauma, we will mainly find the following.
1. Firearms and fireworks
The explosions caused by firearms have a very high volume, between 140 and 180 dB . The acoustic trauma will depend on factors such as the type of weapon, its handling (handling close to the ear being more detrimental), the caliber of the ammunition and the number of salvos we have fired.
The more we shoot, the more likely we are to inflict acoustic trauma.
2. Live music
It will have happened to many when going to a concert, having to stay close to the amplifiers. As soon as it ends, the constant buzzing we hear (tinnitus) tells us that we’ve gone too far with rock & roll. Normally concerts do not use volumes that can be too detrimental to our health, but there have been serious cases of acoustic trauma after attending concerts.
The magnitude of the damage depends largely on the distance we maintain from the amplifiers, the type of music we are listening to (more strident music correlates with greater damage) and factors of sensitivity to auditory trauma.
3. Occupational risks
We have already mentioned that construction personnel usually suffer from chronic acoustic trauma in those cases in which they do not wear adequate protection, but they are not the only group affected. This is also the case for people who work in the musical environment, such as artists, DJs or sound technicians. Even if they keep the volume at acceptable levels, occupational accidents in this field, such as an amplifier going bad, can cause serious damage to your hearing.
To avoid this damage, the smartest thing is to avoid excessively loud sound sources and, if this is not possible, to wear all the protection we can to take care of our delicate hearing. In the long run we will appreciate it, even if it is annoying.
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Bibliographic references
- Fligor, B. (2018). Acoustic trauma from recreational noise exposures. AudiologyOnline, Article 23542. Retrieved from http://www.audiologyonline.com
- De Alharilla Ibáñez, M. (2016). Acoustic trauma and sudden deafness. Medical news.
To the classic question “what do you do?” I always answer “basically I am a psychologist”. In fact, my academic training has revolved around the psychology of development, education and community, a field of study influenced my volunteer activities, as well as my first work experiences in personal services.
