Doctor Audiologist Emel Uğur

Dr. Audiologist Emel Uğur was born in 1982 in Çanakkale. During her 15-year tenure at Istanbul Training and Research Hospital, she primarily worked on Pediatric Audiology (Hearing Loss in Infants and Children), Otological Diseases (Ear Diseases and Hearing Health), and Vestibular System Disorders (Vertigo and Imbalance). In 2015, she joined the Acıbadem Healthcare Group.

About Me

What is Noise-Induced Hearing Loss?

Noise-induced hearing loss is one of the major health problems caused by industrialization and technological advancements. This condition can occur as a result of prolonged, regular, or high-level exposure to noise. Certain occupational groups are particularly at risk. Hearing loss is more frequently observed among individuals working in noisy environments.

• At-risk occupations include construction workers, factory workers, airport personnel, members of the armed forces, musicians, etc.

Chronic exposure to noise leads to damage of the auditory nerves over time. This situation can result in hearing loss as well as other health problems. Non-auditory effects include sleep disturbances and high stress levels.

Government regulatory bodies have developed various regulations and standards to reduce noise exposure. These efforts aim to control noise levels in workplaces and protect employees. Prevention of noise-induced hearing loss is possible through early diagnosis and regular monitoring. In this process, the education of workers and raising awareness are of great importance. There are various methods, such as preventing noise at its source and preventing noise exposure in the worker.

What Causes Noise-Induced Hearing Loss?

Noise-induced hearing loss is a health problem caused by exposure to high sound levels. The occurrence of hearing loss depends on various factors. The loss in question can be temporary or permanent. It also varies depending on the level and duration of the sound exposure.

Occupational noise exposure:

• Mines and factories
• Railway depots
• Construction sites
• Military bases

Environmental noise exposure:

• Highways
• Trains and airplanes
• Nightclubs and sports arenas
• Shooting ranges

These exposures cause damage to the ear structures, reducing hearing ability. Especially sounds of 85 dB and above become inevitable for hearing loss when exposed for long periods. As the sound level increases, the likelihood of permanent hearing loss further increases. Acute sound events such as loud music and explosions can also cause severe hearing damage. Such damages generally occur suddenly and can sometimes be irreversible.

To prevent noise-induced hearing loss, reducing exposure and taking protective measures is essential. This requires greater public awareness about the issue. It is the responsibility of individuals and healthcare institutions to take the necessary steps to protect hearing health.

How Prevalent is Noise-Induced Hearing Loss?

Although it is difficult to determine the exact prevalence of Noise-Induced Hearing Loss (NIHL), this health problem affects millions of people globally. According to the estimates of the World Health Organization, the young population exposed to entertainment sources such as loud music is notably at risk of hearing loss. Individuals between the ages of 12 and 35 fall into this risk group. Moreover, NIHL is more frequently observed among men due to occupational factors. This situation is further reinforced by the following factors:

• Those living in low socioeconomic conditions,
• Occupational groups that are constantly exposed to high noise levels.

Among women, it is thought that hormonal factors may play a role in hearing protection. Research conducted in the United States shows that approximately one in five adults with hearing loss is affected by NIHL. This ratio indicates that NIHL is the second most common occupational disease in the country. If preventive measures are not taken, these rates are expected to increase.

What Happens in the Ear During Noise-Induced Hearing Loss?

During the process of noise-induced hearing loss, a series of biological and mechanical events occur in the ear. The ear collects sound waves and converts these signals into nerve impulses that are transmitted to the brain. The process begins in the outer ear and continues to the inner ear. Noise disrupts this natural process of the ear, leading to various damages.

• The outer ear collects sound waves and directs them to the middle ear. At this stage, the outer ear canal amplifies sounds within a certain frequency range.
• The middle ear converts sound waves into mechanical energy. The eardrum and the chain of ossicles behind it perform impedance matching to transmit the sound energy to the inner ear.
• In the inner ear, sound waves are transformed into fluid movements. These fluid movements stimulate the basilar membrane in the cochlea and produce various responses depending on the frequency of the sound.

The cochlea is the structure that converts sound waves into electrical signals via nerve impulses and transmits them to the brain. Due to the effects of noise, a series of damages occur in the cochlea:

• High-frequency sounds cause more damage at the basal end of the cochlea, while low-frequency sounds affect the apical end.
• The high intensity of the sound increases the pressure on the hair cells, leading to their damage.
• Excessive sound load causes excessive glutamate release at the synaptic connections of the hair cells, subsequently leading to cell death.
• The accumulation of reactive oxygen species damages the cells’ DNA, resulting in permanent hearing loss.

These processes result in either temporary or permanent hearing loss:

• A temporary threshold shift occurs after short-term exposure to high noise levels and usually recovers within a few days.
• A permanent threshold shift occurs as a result of prolonged or repeated high noise exposure and is irreversible.

What Environments Can Cause Noise-Induced Hearing Loss?

Noise-induced hearing loss is especially common in certain environments. The risk of hearing loss increases in places where sound levels that can damage the eardrum are present. Therefore, some environments require particular attention. Firstly, workplaces—especially industrial facilities and construction sites where noise levels are high—pose a significant risk. In such environments, it is essential for workers to use protective headphones.

Additionally, for those living in cities, traffic noise is an important source of danger. Prolonged exposure in areas with heavy traffic flow can lead to hearing problems. Therefore, individuals living in such areas should also be cautious.

• Large event venues such as concert halls and stadiums can have high decibel levels.
• Bars and nightclubs are generally risky environments due to high music volumes.
• Transportation hubs such as airports and train stations are among places constantly exposed to high sound levels.

How is Noise-Induced Hearing Loss Diagnosed?

• The diagnostic process for Noise-Induced Hearing Loss (NIHL) requires a careful evaluation by hearing (audiology) specialists. First, a detailed medical history is taken from the patients and other potential causes of hearing loss are considered. Then, specific audiological tests are performed to determine NIHL.
• Pure-Tone Audiometry: This test provides important information about the frequency and intensity of the hearing loss. A notch observed between 3 and 6 kHz is a typical sign of NIHL, appearing as a result of noise exposure. Finally, the following steps are followed to calculate the degree of hearing loss:

• Hearing thresholds at 500 Hz, 1 kHz, 2 kHz, and 4 kHz are determined for each ear.
• The arithmetic mean of these values is calculated.

• Hearing in Noise Test: This test is used to measure the effectiveness of hearing aids and to evaluate the ability to hear against background noise.
• Speech Audiometry:
  • The Speech Reception Threshold (SRT) determines the threshold at which the patient understands speech,
  • The Word Recognition Score (WR/SDS) evaluates the patient’s ability to discriminate speech.

These tests play a critical role in understanding the degree and type of hearing loss. In particular, low SRT and SDS scores despite normal audiometry results are among the early signs of NIHL.

• Otoacoustic Emissions (OAEs): These are used to objectively assess cochlear health. OAE testing in patients suspected of NIHL offers high sensitivity and specificity.
• Brainstem Evoked Response Audiometry (BERA): This test analyzes auditory brainstem responses to detect synaptopathy. It is particularly used for the diagnosis of hidden hearing loss.

How is Noise-Induced Hearing Loss Treated?

The treatment of noise-induced hearing loss is limited by current technology and medical knowledge. Since hearing loss is a permanent condition, existing treatment methods focus on managing the damage. First, hearing aids offer a basic solution for individuals experiencing hearing loss. These devices amplify sounds in a frequency-specific manner to compensate for the hearing loss. Various types of hearing aids are available and can be adjusted according to the individual’s needs.

For those suffering from noise-induced tinnitus, tinnitus maskers and tinnitus retraining therapy (TRT), as well as neuromodulation applications, can be used. Tinnitus maskers help suppress the ringing sound, while TRT helps strengthen the auditory connections between the brain and the ear.

Additionally, animal studies have shown that magnesium and vitamins may offer protection against hearing loss:

• Vitamin A,
• Vitamin E,
• Vitamin C,
• Vitamin B12.

What are the Complications of Noise-Induced Hearing Loss?

Noise-induced hearing loss can lead to serious issues not only within the auditory system but also in overall health. Chronic exposure to noise can cause an increase in stress hormones, leading to metabolic imbalances. In the long term, this increases the risk of cardiovascular diseases. In addition, sleep disturbances and rest disorders can reduce work performance and lead to accidents. Psychological effects cannot be ignored:

• Depression
• Anxiety disorders
• Lack of concentration
• Tension in relationships

How Can Noise-Induced Hearing Loss be Prevented?

Noise-induced hearing loss is a common health problem, especially in work environments where high sound levels are present. Constant exposure to high decibel levels in the workplace can lead to hearing loss. Taking preventive measures is of great importance to protect hearing health. Both employers and employees should take certain precautions.

• Avoid frequently attending concerts, fireworks shows, and other similar high-sound events
• Avoid environments known to have high sound levels
• Refrain from listening to loud music
• Use protective equipment in noisy work environments

Frequently Asked Questions

Where in the ear does noise-induced hearing loss occur?

Noise-induced hearing loss is the result of damage in the inner ear (cochlea) due to exposure to acute or chronic high levels of noise. It can be temporary or permanent.

The cochlea is the part where the analysis of hearing begins. It is a structure equipped with hair cells that convert sound waves into electrical signals. As a result of noise exposure, these hair cells may be damaged or completely destroyed. Damaged hair cells cannot regenerate, which makes the hearing loss permanent. Therefore, noise-induced hearing loss primarily occurs due to damage to the hair cells in the cochlea.

Does noise-induced hearing loss recover?

Noise-induced hearing loss is related to the duration and intensity of noise exposure. Initially, this type of hearing loss may be temporary and can recover within a few days. Often, tinnitus is more prominent than the hearing loss itself. Primary causes include visiting entertainment venues, attending concerts, being very close to the sound source in noisy environments, or being exposed to sudden explosive noise. Although this condition may be temporary at first, if the individual continues to be in noisy environments, it can become permanent.

Furthermore, when continuously exposed to high levels of noise—especially occupational noise—noise-induced hearing loss can become permanent. Therefore, if protective measures are not taken and early intervention is not provided, recovery is not possible. There is no known treatment for noise-induced hearing loss; hence, it is permanent. The only way to eliminate the life-disrupting barriers caused by the hearing loss is to use hearing aids.

What is the noise level that causes hearing loss?

The noise level that causes hearing loss is determined according to international standards. In line with these standards, the minimum noise level that can damage the hearing system is determined to be 85 dB (decibels). Moreover, these harmful sound waves cover a wide range of frequencies. Therefore, sounds above these values can lead to hearing loss when one is exposed for a long time. Hence, the duration and intensity of noise exposure are critical for hearing health.