The well-known edition of "STAT" informed about new discoveries of American researchers in the field of hearing. It turns out that too intense sounds like those that are heard at concerts of rock performers or in workshops are capable of causing hard-to-detect damage to the human hearing organ.
Due to the fact that the usual ways of quickly determining the health of the hearing aid can not catch such pathology, the hearing can worsen even more, and already irreversibly. Such people after a while start to feel constant noise in the ears and do not perceive conversational speech in a noisy environment.
American researcher Charles Lieberman (Harvard) was so tightly engaged in this problem and dared to designate it as "hidden hearing loss". For a more complete understanding of pathology, the mechanism of perception of sounds in the human ear should be refreshed in memory. We all have the basic organ of hearing - Corti's organ. It is represented by so-called hair cells. Their "cilia" oscillate from the incoming sound wave, thus transforming it into an electrical neural signal. By nerve fibers, signals tend to the brain, and we perceive the world through sounds.
When the hair cells act as a loud sound in all their manifestations, their gradual destruction occurs with a decrease in the auditory function. Of course, hearing impairment can be a consequence of the aging of the body, which is quite natural. But in the case of Lieberman it is necessary to think: is it possible that intense loudness can affect the organ of Corti and without visible destruction of the cells? Veda hearing impairment in some people is not accompanied by changes on the audiogram (a habitual test for fixing the loss of hair cells).
For example, one of rock music fans Matt Garlock (29 years old) and an engineer works so hard about his problems: "When I come home and become surrounded by silence, I feel a ringing in my ears, but it usually takes 2-3 days.
But recently I also returned with a ringing after a couple of noisy parties, but he did not disappear. Then I turned to the doctor, and my audiogram eliminated the hearing changes. " However, Matt himself began to notice that he had to ask questions from people and lean toward them.
In addition to Charles Lieberman, cases of normal audiograms with the clinic for hearing loss in the patient interested in Robert Fayfer (Miami). He said that he met this only with employees of the Air Force, aircraft workers and those young people who like listening to music very loudly.
Lieberman tried to back up his reasoning with animal experiments. He investigated synapses - structures that provide signal transmission between nerve and hair cells. It turned out that even with the loss of half the cells of Kortiev organ changes on the audiogram are not recorded. It's all about the damage to those synapses that directly help signal transmission to the brain. Fortunately, Charles announced the availability of a drug to stimulate the restoration of destroyed synapses and that he himself is a shareholder in the company to develop it.
Now people just have to protect their ears, waiting for the release of such a drug. The researcher, though, has a good hearing for his age (65 years), but some phrases do not disassemble without repetition in a noisy environment. Lieberman writes off this for many years of experience using a circular saw and a grinding machine. "Now - says the scientist - I always use earplugs while caring for my lawn."