Acoustic trauma – causes and symptoms

Anyone who has ever heard a real gunshot or cannon blast, experienced an airbag deploying, or stood too close to an exploding New Year's Eve firecracker knows that some sounds are painful to the ears. Not only that, but some of these loud bangs can even cause significant damage to the ear. Milliseconds are enough to cause this damage.

Below, you can learn more about what is known as "acoustic trauma," from causes and symptoms to treatment and prevention.

What is blast trauma?

Acoustic trauma, or noise trauma, is physical injury or damage caused by noise. In acoustic trauma, the hair cells in the inner ear are damaged because very high sound pressure acts on the ear for a very short time, i.e., approximately 1 to 3 milliseconds. In contrast, prolonged exposure to excessive sound pressure damages the eardrum and ossicles.

Noises that can cause acoustic trauma are at least 140 decibels (dB) loud. By comparison, noises between 40 decibels and 65 decibels are perceived by humans as normal or pleasant. At a volume of approximately 80 decibels or above, the noise is considered to be loud.

Typical risky noises and causes of acoustic trauma include, for example:

• a shot
• a New Year's Eve firecracker
• an airbag deploying
• a burst tire
• a slap in the face
• Loud noises on construction sites
• a nearby lightning strike

These noises generate such high sound pressure that they damage the hair cells in the organ of Corti, the actual hearing organ in the inner ear. As a result, those affected suffer from hearing loss, often in the high-frequency range.

Symptoms: How to recognize blast trauma

Noise trauma can be either acute or chronic. While chronic noise trauma is usually caused by constant and regular exposure to noise, often resulting in permanent hearing loss, acoustic trauma is an acute form of noise trauma triggered by a very short but very loud sound. The following symptoms, among others, may occur after a loud bang:

• earache
• a feeling like "cotton wool in your ears"
• Tinnitus/ringing in the ears (beeping, hissing)
• hearing impairment 
• Hyperacusis (sensitivity to noise)
• hearing loss
• Dizziness, balance disorders

In the case of mild acoustic trauma, most symptoms usually disappear after a short time. In the case of severe acoustic trauma, i.e., when the hair cells in the inner ear have been severely damaged, irreparable hearing damage may occur in some cases, such as tinnitus or permanent hearing loss. 

Acoustic trauma or blast trauma

There are various types of acoustic trauma. These include blast trauma, noise trauma, and explosion trauma.

While acoustic trauma is usually caused by a short, loud bang and the symptoms are mostly as described above, explosion trauma often results in damage or injury to the eardrum due to a very loud, prolonged noise. This can result in combined hearing loss, in which both sound conduction and sound perception are impaired. This can also occur some time after the sound event or worsen over time. 

Noise trauma, on the other hand, occurs when people are exposed to noise over a long period of time or on a permanent basis. It is a typical occupational disease that can lead to hearing loss over time.

Consequences of blast trauma and long-term effects

In many cases, acoustic trauma can improve or disappear. However, it can also damage the hair cells in the inner ear to such an extent that the trauma can no longer be treated.

Possible consequences or long-term effects of acoustic trauma include ringing in the ears or tinnitus, hearing impairment, and hearing loss.

Acoustic trauma diagnosis: When to see a doctor?

It is important that you consult an ENT doctor if you experience typical symptoms of acoustic trauma in order to prevent possible consequences and long-term effects.

The doctor will perform various examinations, such as an otoscopy (ear examination) and hearing tests, to determine whether and to what extent the inner ear has been damaged and whether the patient has difficulty hearing different pitches, for example. The appropriate treatment is then determined based on the diagnosis.

Acoustic trauma treatment

The correct treatment for acoustic trauma is always determined by an ENT doctor. It depends, among other things, on the symptoms and causes.

Explosive trauma medication:

There are various drug treatments for blast trauma. These include, for example, cortisone therapy, oxygen therapy, and what is known as hemorheological infusion therapy.

Hearing aids for acoustic trauma:

Since acoustic trauma can result in hearing loss, hearing aids can help compensate for this in some cases. This allows those affected to hear high-pitched sounds again, for example.

Noiser/Masker:

So-called noise generators or maskers are often used in tinnitus therapy. These are devices that generate a pleasant noise in a specific frequency range in order to reduce or mask the noise in the ear. Noise generators or maskers are sometimes integrated into special hearing aids.

How long does blast trauma last?

The duration of a blast trauma varies from person to person and depends, among other things, on the individual's health, the causes, etc.

In cases of mild acoustic trauma, the symptoms usually subside within a few hours or days. 

In some cases, however, acoustic trauma can also lead to permanent hearing problems. Tinnitus is also possible. If your symptoms have not disappeared after a few days, you should definitely consult an ear, nose, and throat doctor.

Preventing noise-induced hearing loss: Use hearing protection!

There are basically only two ways to effectively protect yourself from blast trauma.

It is best to avoid loud noises, bangs, and noise in general.
If this is not possible, for example, because you work in a profession where loud bangs cannot be avoided, be sure to use hearing protection. This includes various earplugs or noise-canceling headphones.