Tinnitus İn Acoustic Trauma

Time is important for the occurrence of damage to the auditory system due to acoustic traumas. For example, exposure to 90dB begins to cause damage in 8hours, whereas exposure to 120dB can begin to cause damage in 7 to 8 minutes. Heavy traffic produces 80-90 dB, normal conversation produces 60 dB, and headphones of portable music devices (mobile phone, mp3 player, etc.) produce 110 dB at their peak output levels. Ambient noise at a level that would prevent a person from communicating easily with another person may cause an otologic damage that leads to tinnitus as its first sign.

Generally firearms produce sound over 140-dB level. Big-caliber rifles and handguns can produce sound over 175 dB, while a small 22-caliber rifle can produce noise around 140 dB. Reflections of loud noises from the walls in closed areas may increase their trauma creating effects, as a result of their increased echo effects. In addition, modified barrels etc. may cause the gun to produce a louder sound. Protective measures should be taken even if a short time shooting is planned. Hearing and/or tinnitus problems are suffered particularly by hunters, police officers, and military personnel exposed to the noises of big-caliber rifles, hunting rifles, handguns, infantry rifles, rocket launchers, and artillery fire. People engaged in hunting often apply to us during hunting seasons.

The ear, where the problem occurs, is usually the one on the side of the gun barrel during shooting. Accordingly, right handed shooters have often a problem with the right ear. The left ear gets more damage. It is protected partially by the shadow effect of the head. In such cases, generally high-frequency (i.e. sharp sounds) causes hearing loss that can be accompanied by tinnitus. It is important to take protective measures depending on the features of the firearm. If you are a hunter, you can choose a low-caliber single barrel shotgun, pump action shotgun or a semi-automatic rifle. It is important to be careful about the areas, where the shooting takes place, keeping in mind that the effect of sound increases as a result of resonance. Wearing ear protectors that filter the sound and reduce its effect, and keeping the rifle away from the ear when shooting, are of great importance, as well.

Hearing loss or tinnitus after an acoustic trauma is usually temporary, and disappears after 16 to 48 hours. The recovery period can sometimes last up to a week or two. If the tinnitus still continues after a period of one or two weeks, and if it does not lose its severity, it may become permanent. Early treatment increases the chance of success; however, some scientific sources state that the treatment can be delayed for a period of up to a month, in cases of tinnitus caused by acoustic trauma. If it has lasted more than a month, it should be considered to be permanent, and treatment should be started. However, if the level of tinnitus declines significantly with each passing day, you can wait for a while longer.

Besides people mentioned above, musicians, factory workers working in a noisy environment (press operators, mold makers etc.), people who listen to music at low volume levels for a long time, and those who listen to music constantly on headphones are at risk as well. Airbag deployments during traffic accidents produce sound pressure levels of approximately 160-180 dB. People exposed to such sounds are candidates for potential hearing loss and tinnitus.

Another point to take into consideration is music organizations intended for wedding, celebration of circumcision, etc., which are common in our country. High-volume loudspeakers used in activities such as concerts and wedding ceremonies have capacities over 1000 watts. It should also be kept in mind that there are many other sounds that may cause hearing loss and tinnitus, such as the sounds of gunshots and shrill pipes played close to the ear in traditional wedding and engagement ceremonies.

What are the changes that high sound makes in hearing physiology and anatomy?

If we look at the normal hearing physiology, we see that the sound waves strike the eardrum when they reach the ear, and then the eardrum vibrates and delivers the vibration to the three tiny bones (malleus, incus, stapes) located behind the eardrum in the middle ear area, which are interconnected with each other. Because of their arrangement and positions, these tiny bones (ossicles) have the features of absorbing and filtering sharp sounds (up to a certain degree of sound power). Stapes is an ossicle connected with the inner ear structures. The sound is transmitted to the inner ear through these ossicles. There are cells called "hair cells" in the fluid-filled portion of the inner ear. The fluid inside the inner ear waves due to sound transmissions and consequently stimulates the hair cells. These cells are arranged according to certain frequencies, within the structure called cochlea. The cells in the cochlea are stimulated at different frequencies, and then the resultant electrical signals start the hearing process in the brain. These electrical signals are transmitted by the cells called neuron to the pons, cerebellum, brain and then finally to the gyrus in the auditory center of the brain, where all the frequencies are analyzed. There is a highly wide range of sound analysis scale in that section. This section acts just like a computer processor.

In cases such as artillery fire, bombing, rocket launching, etc., the extremely high sound and the pressure caused by its reflection may cause eardrum rupture and partially dislocate the ear ossicles, depending on the openness or closeness of the area, where the activity is carried out. Hearing loss and tinnitus may occur in case of dislocation of the stapes bone at the connection point of the inner ear and middle ear, as a result of an extreme sound trauma, and in cases where the inner ear fluid leaks into the middle ear due to a limited damage to the connection point.

Hearing loss and tinnitus may occur at especially high frequencies, as a result of losing the features of the receptors in the inner ear, due to excessive acoustic trauma. In other words, the sensory microphone part of the auditory system may be malfunctioned.

Pathologies are not limited to these structures. They also include problematic hearing neurons that travel in the brain. The excess electrical charge created by the acoustic trauma may cause tinnitus and deterioration in the structures of the neurons. Sound traumas in the analysis section of the brain may cause frequency defects and impairments.

It should be kept in mind that any point of the auditory system may be responsible for hearing loss and tinnitus caused by exposure to excessively loud sound. Therefore, in those who suffer from hearing loss and tinnitus due to exposure to excessively loud sound, it is not possible to treat hearing loss in late periods but tinnitus can be treated. This is important because the area of the pathology and the status of the damage are important in terms of treatability level. In other words, some of such tinnitus conditions can be treated, depending on the status of the pathology, while some of them cannot be treated.

What are the important pre-treatment tests?

The condition should first be determined very clearly, for being able to decide on the treatment or initiate a treatment. In case of lack of that clearness, it is not possible to know why and how to treat what. Many people exposed to acoustic trauma, who have had tinnitus, ask whether they could be treated. Since phenomena occur at one or several points, the chance of treatment can be determined after performing certain tests. For the clarification of the patient's condition, hearing tests involving high frequency audiograms and specific FMRI examinations are needed. FMRI examination is a technique performed by an advanced MRI device capable of providing sections at the cellular level, which details the of tinnitus and hearing areas and identifies the source of the problem.

Our patients generally confuse routine MRI devices with such devices, and think that the available results of their previous MRI examinations would be adequate in this regard. The specific FMRI (Multiparemetric Functional Magnetic Resonance Imaging procedure) technique is quite different. Beyond the normal MRI techniques, it examines inner ear structures to provide detailed information about the cellular relationships at the neuronal level. Thousands of images are taken at the end of a study that takes about 2 hours. Analyzes of these images provide very important findings. The points creating the tinnitus are identified. This affects the direction of the treatment as well as its chance of success. FMRI is not harmful to the body. Those who carry metal (dental implants, stents, broken tooth plates, etc.) in a medically significant amount, should report them in advance. 
There is information about which medical metals are acceptable for the device Patients, who are eligible in this regard, are accepted for the examination.

How to decide on the treatment, and what can be done?

If the chance of treatment is foreseen, based on the examinations, a number of treatment options for tinnitus is brought to agenda. This will be determined in accordance with the condition of the pathology in the patient. It should not be kept in mind that every acoustic trauma does not involve the same pathological condition. It is possible to perform medical treatments intended for repairing damages, depending on the damages in the auditory paths and the condition of the pathology; treatment procedures for regulating impaired electrical activities; and r-TMS treatments that can provide normal condition. Intratympanic cortisone injections can be used at acute stages. Treatments should be performed after examinations, in accordance with the condition of the pathology. In our studies, we can detect points that create tinnitus, with almost 100% accuracy. After that, we act in accordance with the findings of the patient. If there is a chance of treatment according to the findings, we carry out the treatment procedure. Even if the patient is eligible for the treatment, it should be remembered that the tinnitus treatments are not yet capable of providing 100% success. The benefit rate is 65 - 70%; and besides, there is also the possibility of failure. However, it should be kept in mind that even these rates can be a hope, particularly in the treatment of tinnitus. Therefore, treatments should be tried.

Some part of the information in this text is based on medical literature, while some others have been obtained as a result of our own scientific studies. This text is for information purposes and belongs to Surgeon Dr. A. Ahmet Sirin.All rights reserved.

Note: The content of the page is for information purposes only. Please definitely contact your physician for diagnosis and treatment.