noise-induced hearing loss
Introduction
Introduction to noise Noise induced deafness (slow-induced deafness) is a slow and progressive sensorineural deafness caused by long-term hearing loss. It is early in auditory fatigue. It can be gradually recovered after leaving the noise environment. It is difficult to recover after a long time. deaf. In addition to hearing damage, noise can also cause headache, dizziness, insomnia, high blood pressure, ECG changes, and can also affect the peristalsis and secretion of the stomach. Therefore, reducing or eliminating noise is a very important issue in today's environmental protection work. Noise is common in people working in highly noisy environments, such as ship engineers, tank drivers, aircraft field personnel, telephone headsets and wireless workers, riveters, blacksmiths, weavers, etc. basic knowledge The proportion of illness: 0.001% Susceptible people: no specific population Mode of infection: non-infectious Complications: blast deafness, sudden deafness
Cause
Noise cause
Damage factor
Long-term operation in the noise environment with noise level greater than 90dB can cause damage to the cochlea. The degree of damage to the cochlea is affected by the following factors.
(1) Time: The longer the work in a noisy environment, the greater the degree of hearing damage.
(2) Noise intensity and nature: high frequency and high intensity are serious to hearing damage. Intermittent noise is more harmful than continuous noise. Vibration plus noise is more harmful than simple noise.
(3) Working environment factors: A narrow workplace is more vulnerable than an open working environment, and the closer it is to the noise source, the more vulnerable it is.
(4) Physical condition: Middle-aged and elderly people are more susceptible to noise damage than young people. Infirm people are more vulnerable than strong ones. Patients with sensorineural hearing loss or otitis media are more susceptible to injury, and their physical physiques are different.
pathology
Under the influence of long-term noise stimulation, the blood vessels of the cochlear vein first appeared blood circulation disorder, the hair cells of the spiral hair were damaged, and the hair cells were damaged. In the severe cases, the inner hair cells were also damaged, followed by the degeneration of the spiral ganglion to the end of the cochlear basal lap and the second. The lesions in the circle are most obvious. Here, close to the tympanic cavity, the blood vessels are thin and susceptible to noise. The cochlear basal ring mainly receives 4000 Hz sound stimulation, so early patients have obvious hearing loss at 4,000 Hz. Some people think that it is related to the resonance of the external auditory canal, because the resonance frequency of the external auditory canal is about 3,000~4,000 Hz.
Prevention
Noise prevention
1. Control the source of noise
This is the most active and fundamental method. In the construction plant and the installation of the machine, various soundproof and shockproof and sound absorbing measures should be adopted. For example, the noise workshop is separated from other workshops, and trees are planted in the middle; the wall and ceiling of the workshop are equipped with sound absorbing materials. The installation density of the machine should be dilute; between the machine and the foundation, the appropriate filling material should be used between the metal surface and the surface; the noise of the pipeline should be protected by the banding method, and the airflow noise can be silenced or expanded. Reduce the noise to within the national protection standards (85 ~ 90dB).
2, reduce contact time
If you take a break in the work room in the soundproof room, or reduce the daily and weekly contact noise time, you can also reduce the incidence. It is also possible to rotate the work according to the actual situation and also reduce hearing damage.
3, ear sound insulation
Wearing earplugs, earmuffs, soundproof caps and other soundproofing equipment, generally in the 80dB noise environment for long-term work should be equipped with simple earplugs; 90dB or more must use protective tools. For the simpler, you can use cotton to close the outer ear canal, and then apply Vaseline, the sound insulation value can reach 30dB.
4. Health monitoring
Hearing should be checked before employment. People with sensorineural deafness and noise sensitivity should avoid working in a strong noise environment. For those who are exposed to noise, the hearing should be checked regularly, and early hearing impairments should be discovered in time and properly treated.
5. Strive for early treatment.
Complication
Noise complication Complications , deafness, deafness, sudden deafness
1. Alzheimer's disease
Deafness is often accompanied by tinnitus or re-vibration, which makes the language discrimination and expression ability of the elderly extremely declining, resulting in the lack of interpersonal communication in the elderly, the character becoming lonely and quirky, and may lead to Alzheimer's disease.
2, children's mental retardation
Deafness causes the newborn to lose the power of "listening" and "speaking", unable to obtain outside information, and the development of the language system is seriously affected. Hearing loss will delay the normal development of their intelligence and language. Lead to children's mental development is not perfect.
Symptom
Noise sputum symptoms Common symptoms Hearing loss Tinnitus, ear palpitations, dizziness, insomnia
The main symptoms are progressive hearing loss and tinnitus. The early hearing loss was at 4000 Hz. Therefore, it had no obvious effect on the normal speech. Only in the audiometer examination, the hearing damage gradually developed to the high and low frequencies, and finally decreased. At this time, the hearing impairment was felt. Tinnitus and deafness can occur at the same time, or can occur alone, often high-pitched tinnitus, disturbing day and night.
Examine
Noise inspection
Examine the external auditory canal and tympanic membrane: perform tuning fork examination and pure tone hearing threshold to find out the nature and extent of deafness. For children and non-cooperative adults, guest observations such as acoustic impedance measurement, auditory brainstem response audiometry and cochlear electrograms are also available.
Hearing test: A sound test can be used on the watch. Before the medication, the test was used to test the hearing, and during the medication, the same watch was used to test the hearing. Pay attention to the position of the table, each time should be placed in the same orientation, and should not be attached to the ear skin or the upper end of the bone should make the watch a certain distance from the auricle. The sound that is heard in this way is the sound transmitted through the air. Otherwise, it is the sound transmitted through the bone, and the actual situation of hearing cannot be faithfully reflected. In the trial, if the hearing loss is found after administration, the possibility of cochlear system poisoning should be considered.
Diagnosis
Noise diagnostic identification
diagnosis
There is a clear history of noise exposure: that is, the history of long-term overtime work in an environment of more than 85 dB(A) as stipulated in the Noise Industry Hygienic Standard for Industrial Enterprises of the People's Republic of China promulgated in 1980. There was no abnormality in the general examination of the ear, nose and throat. Pure tone audiometry is inductive.
The main complaint was bilateral tinnitus and progressive deafness without other pathogenic factors. Hearing tests for those suspected of being paralyzed must use an audiometer that is calibrated by the metrology department according to the International Organization for Standardization ISO-389, ISO/DIS-7566. In a soundproof room with a noise floor of less than 30 dB (A), it is measured by an experienced professional audiologist, according to the rising method specified in ISO/DIS-6180, after the subject has been out of the noise environment for 12-16 hours. The hearing threshold measured for subjects over 40 years old needs to be corrected according to the normal person's age and gender function according to ISO/DIS-7029, and then the average hearing threshold of 500, 1000, 2000 Hz air conduction is calculated to determine the degree of deafness. With level. If the degree of hearing loss in both ears is different, the ear should be graded according to the damage. Since the noise is high to damage the high frequency first, countries have entered the tendency to calculate the average hearing loss by including the hearing threshold of 3000 or 4000 Hz.
Differential diagnosis
Identification with drug-induced deafness, congenital deafness, infectious deafness, senile deafness, and sudden deafness.
