In chronic nature of the sound, squeak, high whistle, hum and other noise, heard a man in the absence of the various external sources, becoming a serious problem. Previously, this disorder is trying to cure the effects on the auditory nerve, but in some cases, this resulted in complete deafness, but the ringing in your ears without any changes remained, suggesting that it is not only in the ear and auditory pathways to the analyzer and in the brain. So why the brain is still necessary to create a phantom noise?
Tinnitus is often accompanied by hearing defects, but not in all cases. Such exceptions just knocked all researchers astray. That's why scientists have suggested that the hearing defects exist, they simply can not be determined by standard methods. It was tested 15 people with chronic tinnitus and 18 without it. Out of all no one complained at the hearing. Everybody listen to the recording gave a very loud high-frequency sounds. At this time, the scientists recorded the brain activity of participants.
As it turned out, those who have had ringing in the ears, with respect to audible sounds by the brain had been shown a feature. Probably due to nerve damage fabric is passed from ear to the brain by the auditory nerve, the nerve impulse was slightly weakened. However, activity in the auditory brain areas were discernible in the two groups. The brain is somehow compensated for the weakness of the incoming signal.