Acoustic trauma (bang trauma)

When deciding whether to preserve hearing or vision at all costs, if both are not possible, many prefer to do without hearing, as it does not seem to be so important. This opinion is also reflected in daily life, where it is noticeable that hearing is insufficiently protected. Due to this careless handling of the ear, a so-called acoustic trauma occurs far too often, the consequences of which one only becomes aware of when one feels a hearing loss or tinnitus on one's own body.

The acoustic traumas can be divided into a blast trauma, an explosion trauma, an acute noise trauma and an acoustic accident.

The blast trauma

In a blast trauma there is a sound pressure of more than 150dB for a very short moment. The cause can be, for example, a gunshot or a firecracker. The result is a sometimes drastic hearing loss and often also tinnitus. However, since no structures in the inner ear are damaged, the symptoms usually disappear.

The explosion trauma

In the case of an explosion trauma, the sound level is about the same as in the case of a blast trauma, but it has a much longer effect on the ear. This can also damage or even destroy inner ear structures such as the eardrum or the ossicles. Causes include explosions, blows to the face or even the deploying airbag. In addition to acute hearing loss and tinnitus, there is usually also pain. The hearing impairment continues to increase in the course of the disease, and recovery occurs in only a few cases.

Acute noise trauma

In acute noise trauma, the sound pressure level is only slightly above 100 dB, but the noise affects the ear for several minutes to hours. This can be the case, for example, in everyday working life or when going to a disco. The result is bilateral hearing loss and often also tinnitus. Within a few hours or days, however, the symptoms disappear.

The acoustic accident

An acoustic accident can occur even at slightly increased sound pressure levels if the cervical spine is also in an unnatural position. This is typical when working with a drill on the ceiling. Here, too, acute hearing loss and tinnitus occur. In the course of a few hours, however, the symptoms recede completely.

Acoustic trauma is always caused by too high and/or too long sound pressure. This not only causes hearing loss, but often also tinnitus.

Damage to middle and inner ear structures

In acoustic trauma, middle and inner ear structures can be damaged or destroyed. For example, the eardrum can rupture in blast trauma, or the ossicles can be dislocated.

In blast trauma, there can be damage to the inner hair cells. We absolutely need these to process the sound waves entering the ear into electrical signals that can be perceived by the brain.

The symptoms of all acoustic traumas include a loss of hearing and in most cases also a so-called tinnitus. However, the duration of the symptoms and the exact causes vary from case to case.

Acute hearing loss

The hearing loss resulting from trauma varies greatly and is also perceived differently. Some describe it as a reduction in sound, others think they hear everything as if through cotton wool. It is also often described as hearing through a malfunctioning cell phone.

Medical professionals often refer to this type of hearing loss as a C5 depression. This term comes from studies with old audiometers that used C tones in different octaves. The fifth C of the sequence was approximately at a frequency of 4,000 hertz. Our hearing is particularly sensitive in this range, which is why damage is mainly heard here. It becomes noticeable that, for example, sibilant sounds of speech are understood more poorly, even if the brain naturally tries to compensate for the weakness.

Tinnitus

Everyone is familiar with tinnitus, but often only those who suffer from it know exactly what it is. It is an acoustic perception, but it cannot be attributed to a sound source or a sound located in the room. So actually the sound does not exist, but it is still heard. In this sense, it is usually a high-pitched whistling or humming sound. But also a hissing, hissing or knocking is possible.

Depending on the volume and occurrence, the tinnitus is individually different disturbing. Especially a loud and persistent tinnitus can be a very great psychological burden, which in the worst case can even be accompanied by a complete inability to work.

The diagnosis can usually already be made through the anamnesis, in which not only the typical symptoms, but also possible underlying causes are described. A further examination is not necessary in many cases, as the symptoms quickly disappear.

Otoscopic examination of the ear

Nevertheless, an otoscopy should be performed in any case. Everyone knows this from a normal examination, where the eardrum is viewed with an otoscope. Usually, acoustic trauma does not show any injuries, only in the case of blast trauma they may be present.

Quantifying hearing loss with audiometry

Audio audiometry can be used to determine exactly whether hearing loss is present, the frequency range in which it is present, and the severity of the hearing loss. In this way, the damage can be accurately assessed. This is especially important when it comes to treating the hearing loss with a hearing aid.

Especially if the eardrum has been spared, one tries to resort to so-called rheologically active substances in the therapy, which are given as infusions. These should improve the flow properties of the blood, because it is assumed that the blood circulation of the inner ear plays a major role in hearing loss. The same substances are also administered in cases of hearing loss, for example.

Surgical intervention to reconstruct the eardrum

If the eardrum is damaged, surgery may also be considered to reseal it. Sometimes the entire eardrum can be replaced artificially to restore adequate hearing.

Physical therapy of the cervical spine

In the case of an acoustic accident, physical therapy of the cervical spine is particularly helpful in restoring blood flow to the ear. In most cases, further measures can be completely dispensed with.

Overpressure treatment as ultima ratio

If the therapy is unsuccessful, a treatment with overpressure can also be tried. This relieves the inner ear and allows it to recover from the damage. Especially in the case of blast trauma, early treatment in the positive pressure chamber can greatly improve the prognosis.

The prognosis depends mainly on the start of the respective treatment. If the diagnosis is made early and the appropriate therapy can then be started in time, the chances are good that the hearing will recover. Successes are seen within the first four to six weeks. If they fail to appear, one must reckon with chronic damage.

Poor prognosis for tinnitus

However, the prognosis is poor with regard to tinnitus. These disturbing noises remain with a not negligible part of the affected persons, even with the best therapy. However, these are described by the greater part at least as bearable, because the tinnitus is only audible in very quiet situations or is only very quiet.

In many cases, the prevention of acoustic trauma would be very simple. One would only have to protect the hearing from loud noises by taking appropriate protective measures. This means using hearing protection when working with loud machines or even during fireworks.

Unfortunately, however, this is only done far too rarely. Because hearing is only really appreciated when you already suffer from hearing loss or annoying tinnitus!