Noise-induced hearing loss definition
Noise-induced hearing loss results from very severe and/or long-term noise exposure to the ears, which is why it is also abbreviated as NIHL (=noise-induced hearing loss). The type of hearing loss is classifiable as a sensorineural hearing loss because there is impairment of both sound reception and sound conversion to electrical signals. It can be divided into acute and chronic forms of noise-induced hearing loss:
Acute noise-induced hearing loss
Acute noise-induced hearing loss is differentiated into four subtypes:
- Acute noise-induced hearing loss - occurs with prolonged exposure to a high sound pressure level (> 100 dB)
- Acute acoustic trauma - occurs with sudden, intense sound pressure (> 150 dB)
- Explosive trauma - results from a blast wave (> 150 dB) that damages both the inner ear and eardrum
- Acoustic accident - occurs due to short-term exposure to levels between 90 and 120 dB in the absence of blood flow to the ear (caused by the cervical spine)
Chronic noise-induced hearing loss
With daily noise exposure (> 85 dB) for several hours per day, noise-induced hearing loss can develop over years. Predominantly, hearing loss develops in the context of a job performed in a noisy environment, as well as during noisy hobbies.
Noise Hearing Loss Causes
Noise-induced hearing loss, true to its name, is caused by intensive noise exposure. When sound hits the hair cells of the inner ear, the hair cells naturally bend and straighten against the pressure. However, energy is required for this process. The energy requirement increases with increasing loudness - if the sound intensity is too high, there is no longer a sufficient energy supply. The consequence of this is that the hair cells tire and the affected person gets the impression that he has become accustomed to the loudness. However, the consequence of fatigue is damage or even death of the hair cells.
First, the sensitive hair cells that perceive especially quiet sounds die. Only in the course of further noise pollution, the hearing is increasingly destroyed and the hearing loss worsens. How quickly the die-off proceeds depends on various influencing factors:
- Duration of exposure
- Personal factors, including:
- Consumption of alcohol
- Circulatory weakness
- Inhalation of solvent vapors
The hearing fatigue is thus virtually the first stage at which the hair cells can reestablish themselves given sufficient recovery time, and hearing is reversible. However, with long-term, intense exposure, the second stage is reached and irreversible damage occurs. That is, the hearing cells die irreparably, without the possibility of recovery.
Noise Hearing Loss Diagnosis
HNO physicians or hearing care professionals perform a hearing test for diagnosis. The results will indicate whether hearing impairment exists and what form of hearing loss is present. In the case of noise-induced hearing loss, those affected show the hearing loss
typically especially in a specific frequency range. For a reliable diagnosis, further indications of noise-induced hearing loss are asked for in the amnestic interview in order to draw the distinction from other forms of hearing loss.
Noise hearing loss symptoms
Due to its gradual development, noise-induced hearing loss is often not easy to detect. However, a number of symptoms may raise suspicion:
- Typically, the hearing loss is unilateral (unilateral), only in rare cases bilateral (bilateral)
- The high-frequency range is affected first, other frequencies only later in the course.
- Accordingly, the first thing that is often noticed is that children's and women's voices are no longer understood
- Can occur suddenly, similar to a hearing loss
- Often accompanied by tinnitus
In addition, there are classic symptoms of hearing loss:
- Others are difficult to understand
- It seems as if others are mumbling
- Comprehension limited in noisy environments or outdoors
- Speaking loudly
- Television sound noticeably loud
Noise hearing loss prognosis and treatment
Because the hair cells are irreparably destroyed in noise-induced hearing loss, hearing performance cannot be restored. Thus, the prognosis is: incurable. Hearing aids can help, but only insofar as they raise sounds so that the patient's hearing threshold is exceeded. If the hair cells of a frequency range are completely destroyed, hearing in that range is no longer possible - even with hearing aids. If the damage is severe, the use of a hearing-aid implant is also conceivable, for example, a cochlear implant.
Preventing noise-induced hearing loss
So, the main thing is to prevent noise damage. To do this, the following rules should be observed:
- Do not stay too long in noisy environments
- Allow your hearing sufficient time to recover from noise exposure
- Use hearing protection
- If your hearing is already damaged, resort to an ICP hearing aid for the workplace or noisy hobbies