Acoustic trauma or sonic trauma is damage to the hearing organ caused by exposure to extreme noise and pressure on the ear. It can cause permanent injury and permanently reduce hearing ability.
What is acoustic trauma?
Acoustic trauma, or acoustic trauma, is damage to the hearing organ caused by exposure to extreme noise and pressure on the ear. Acoustic trauma is damage to the hearing organ caused by exposure to noise and pressure for a short period of time. The ear can compensate and withstand a certain amount of pressure and loudness, but if the levels are too high, it will be damaged. The human hearing organ consists of an external part divided into auricle, ear canal and middle ear. The middle ear is separated from the ear canal by an elastic membrane (eardrum). The outer part is also called the sound-conducting apparatus, because this is where sound hits and is transmitted to the inner ear. The inner ear is composed of the cochlea and the organ of balance. The extremely sensitive cochlea receives the sound and sends the signals to the brain; the organ of balance is responsible for registering the position and movements of the head. If strong noise hits the ear, either as a sudden short bang or permanently, it can no longer process these stimuli and acoustic trauma occurs. Depending on the type of noise source, a distinction is made between explosion trauma, bang trauma and noise trauma.
Causes
The cause of acoustic trauma is excessive noise. There are three types. We speak of acoustic trauma when a loudness of more than 150 db acts on the ear for a period of less than 3 ms. This is the case with rifle shots or firecrackers. Blast trauma results from a loudness of more than 150 db lasting longer than 3 ms. Causes of this type of acoustic trauma include blasts or the explosion of an airbag. A slap in the face can also cause blast trauma. Noise trauma results from sustained excessive noise, such as that found at a disco, during construction work, or at rock concerts. In all three types of causes, the hearing organ is injured, triggering acoustic trauma.
Symptoms, complaints and signs
Individuals who have been exposed to a loud bang usually experience acute hearing loss in one or both ears immediately afterward. In addition, tinnitus may occur, which is a persistent, high-frequency noise in the ears. After a blast trauma, there is usually hypersensitivity to sounds. There is dizziness, loss of balance and other symptoms caused by temporary or permanent damage to the eardrum. A severe blast trauma may also be associated with a ruptured eardrum. Then, in addition to the symptoms mentioned above, there is usually pain in the ear, slight bleeding and nausea. In addition, those affected experience rotary vertigo and suffer from jerky eye movements, the so-called nystagmus. If the eardrum injury is very extensive, there may be other symptoms such as facial paralysis. An inflammation of the middle ear can also occur. This is usually manifested by pain in the area of the affected ear canal as well as slight discharge. In exceptional cases, affected individuals suffer permanent hearing loss after a blast trauma. In the absence of treatment, severe acoustic trauma can lead to complete deafness. However, based on the symptoms and complaints mentioned above and a medical history, the trauma can usually be quickly diagnosed and specifically treated.
Diagnosis and course
Acoustic trauma can result in various injuries to the ear. The eardrum may rupture, the ossicles may tear apart, and the windows to the cochlea and organ of balance may also rupture. Often there is ear pain and decreased hearing performance. Ringing in the ears (tinnitus) or balance disorders and dizziness are also possible. After a blast trauma, symptoms often improve a few days after the event, but in about half of the cases, the damage is permanent. The ear usually does not recover from blast trauma and the disorders persist. Noise trauma, i.e., sustained exposure to excessive sound, usually results in permanent hearing loss for certain high frequencies. This is referred to as a high-frequency hearing loss.For the diagnosis of acoustic trauma, the patient’s history and knowledge of the triggering event are important. With a hearing test, the doctor checks the hearing ability and draws a so-called audiogram, in which the hearing ability and hearing loss are shown. Other special tests can be used to determine exactly which parts of the ear were damaged by the acoustic trauma.
Complications
Various complications can occur with acoustic trauma. In the worst case, the ear canal is so severely injured after the acoustic trauma that hearing loss or complete loss of hearing occurs. Hearing loss cannot be readily treated because there is no specific treatment for the eardrum. In many cases, the patient must live with the condition and is dependent on the use of a hearing aid. This can lead to severe limitations in everyday life. Especially in young people, hearing loss can lead to depression and a reduced quality of life. In most cases, after an acoustic trauma, noises occur in the ear. This may be a hissing or a beeping sound. Whether these noises disappear cannot be predicted. Often they occur only temporarily. If the noises are permanent, this can lead to headaches and insomnia in the affected person. This leads to fatigue and a general aggressive mood. In addition, pain in the ear or balance disorders may also occur. The patient complains of dizziness and nausea. After a blast trauma, a doctor should always be consulted to avoid consequential damage.
When should you see a doctor?
Specialist treatment is not necessary for every form of acoustic trauma. After a blast trauma, hearing function is usually restored after a few days. If symptoms persist, treatment by a specialist is advisable. If there is still pain in the inner ear after a trauma, even after hours, a specialist should check whether the sound conduction apparatus is damaged. In addition to stabbing pain and hearing noises, bleeding in the ear is a clear indicator that treatment is needed. These severe forms of acoustic trauma must be treated with medication and healing overseen by a medical professional. Complaints affecting hearing function develop in many over a long period of time rather than as a result of trauma. If the hearing ability decreases permanently, a medical diagnosis clarifies the cause. The specialist determines which parts are damaged by examining the outer ear. If chronic hearing loss is suspected, it is compulsory to report it, as the disease may restrict the person’s ability to work. If necessary, a specialist can determine exactly how severely the hearing is damaged and which frequencies the patient can still perceive.
Treatment and therapy
Treatment for acoustic trauma depends on how severely the ear is damaged. In most cases, a therapy similar to that used for hearing loss is used. Circulation-enhancing infusions and cortisone are administered, and the cortisone is often delivered directly to the inner ear. In the case of blast trauma, treatment is often with positive pressure. This involves placing the patient in a hyperbaric chamber where he or she is exposed to high ambient pressure while breathing pure oxygen. This increases the concentration of oxygen in the blood, which counteracts infections and promotes healing of injured structures. If injuries to the middle ear have occurred during the acoustic trauma, they are treated surgically. In a microsurgical procedure, the ossicles can be restored using a plastic and ruptures (tears) of the eardrum or the windows to the inner ear can be closed. The healing phase of acoustic trauma lasts about six weeks. If symptoms are still present at that time, they must be expected to persist.
Outlook and prognosis
Healing proceeds according to the severity of the damage to the ear. In chronic noise trauma, no improvement in hearing function can be expected. The damaged hair tissue cannot regenerate, and support from hearing aids becomes necessary. Damage caused by short-term exposure to sound has a more positive healing record. Destroyed parts of the sound apparatus such as the eardrum are regenerated by the body or covered surgically and recover after a few weeks.Only in severe cases is there a risk of loss of hearing function. However, if a damaged ear is exposed to high volume levels again after healing, the probability of recurrence of symptoms is higher than in a healthy ear. A common complaint of damaged individuals is the occurrence of chronic ringing in the ears, which is perceived with varying intensity. After trauma or periods of great psychological stress, tinnitus disappears in most cases after a few hours or days. Some ear noises recur after trauma, especially in stressful situations. Treatment by a specialist hardly helps with ringing in the ears, even covering with absorbent cotton is of no use. In severe cases, tinnitus can also plague sufferers for a lifetime.
Prevention
One can prevent acoustic trauma by avoiding places with high noise pollution. At concerts, disco visits or other events with extreme noise, one should protect the ears with special earplugs.
This is what you can do yourself
For successful healing after acoustic trauma, affected individuals should gently restructure their daily lives. Patients themselves contribute a lot to their own quality of life and can alleviate symptoms with simple means. After a blast or explosion trauma, patients should under no circumstances continue to be exposed to noise levels above 85 decibels. The inner ear needs rest to prevent further damage to the damaged sound apparatus. Covering the auricle with absorbent cotton or cloth often helps. Cooling should be avoided, as the reduced blood flow to the skin can interfere with the healing process. In the case of tinnitus or chronic noise trauma, it is primarily the psyche of those affected that is burdened. Many patients drown out disturbing ear noises with headphones and soft music – if only one ear is affected, this method is also suitable during the day. Wearing headphones on both ears would endanger everyday life in road traffic and is prohibited by law on bicycles. The sensitivity to sounds resulting from the inner ear injury and the loss of hearing function in certain frequency ranges also make contact with other people difficult. Openness is the best approach here – if the personal environment knows about the injury, people can be more considerate.
