Causes of deafness
Disease. Some diseases may end in deafness.
Noise.Extremely loud noise or prolonged exposure to moderate noise can damage the eardrum and middle ear, causing a decrease in hearing and deafness over time. The main victims of this are people working in noisy environments, as well as lovers and performers of loud pop music.
Congenital deafness.Congenital disorders can range from a total absence of ears to small defects in internal structures. The latter are often treatable by surgery. Congenital deafness can be caused by heredity (genetic defects). It can also be the result of certain infections in the mother during the first months of pregnancy, including rubella, influenza and syphilis. If something about how your child reacts to sounds bothers you, consult your doctor.
Otosclerosis.This is a disease in which a stirrup is stuck in an oval window due to the deposition of a new bone. This affects about one person out of 250, more often men.Surgical intervention can make some improvements, but it's impossible to stop the disease-causing process (although it can stop by itself).
Hearing Aidswork by increasing the sound. If the gain is large enough, the sound can overcome the blockage or damage that led to conductive deafness and break into the inner ear. Sound amplification seems to be able to help in many cases of perceptual deafness. However, sometimes the device can not make speech distinguishable - it only makes senseless sounds louder. The characteristics of the hearing aid depend on:
- frequency range. The sounds of normal speech usually range from 500 to 2000 vibrations per second;
- the degree of amplification;
- the maximum amount of sound that the device is capable of providing. Too loud sound makes speech incomprehensible and / or damages the mechanisms of hearing.
Plug-in receivers are the most common type of hearing aid. They are tailored to the shape of the ear canal and form an excellent stopper. Not a single sound escapes, feedback feedback (echo effect) is minimal or absent, and background noise is also minimal.They can be very small and, if transistors are used, do not need wires or connections. A high level of amplification is possible. The only problem with hearing aids is "reverse acoustic communication". This is a re-amplification of the sound vibrations that have already passed into the ear, but have partly leaked back.
Flat receivers are fitted to the shape of the auricle and held in place by a metal mount. They are usually applied only if there are permanent discharge from the ear or if a serious operation has been carried out on the mastoid bone. Due to poor contact, many sounds are lost, and reverse acoustic coupling generates a large background noise.
Bony conductors amplify sound waves and send them through the bones of the skull, and not through the ear canals. They are inconvenient and not very effective and are usually applied only if some ear disease does not allow the use of plug-in receivers.
Other tools and development
To improve the quality of life of deaf people, telephones with amplifiers, flashing lights instead of telephone and door bells, remote headphones and creeping lines for televisions have been developed.New medical developments include snail implants (which help with nervous conduction deafness) and temporal bone implants (with bone conduction deafness).
Snail implants consisting of one or more electrodes implanted in or near the cochlea, a stimulation receiver implanted in the mastoid process of the temporal bone, and an external speech processor began to be used in the late 1980s. They were thoroughly tested, and it was found that they very successfully cured deep deafness in adults. Miniaturization, frequency manipulation techniques and noise generation masking tinnitus are likely to advance the technology of hearing aids, so that people with hearing impairments, including a growing number of older people, can expect the appearance of devices that exactly match their specific spectrum of deafness and overwhelming interfering background noise.
Each person has a natural rhythm of sleep and wakefulness, based on the daily cycle of rhythms. About a third of his life a person spends in a state close to the unconscious. However, a sleeping person maintains an awareness of aspects of his environment, such as noise and light, and some parts of his brain and body are turned off less than others.
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