The ear receives external sound stimulation, which produces the feeling of hearing sound in the ear, which is a normal auditory function. If there is no sound source in the outside world, but subjectively feel a variety of sounds, this is tinnitus. The mechanism of tinnitus is complex and can occur in a variety of situations, summarized as follows:
The first is physiological tinnitus. Inside the body, vascular pulsation, blood flow, muscle contraction, joint activity, breathing movement, etc., will occur a weak sound, which is closer to the ear, will feel the sound. Normally, due to the outside world has a stronger sound, this weak sound masked, and did not feel out. But if you walk into the soundproof room or in the quiet late at night, sometimes you will feel a faint ringing in the ear, which is physiological tinnitus.
The second is conductive tinnitus. The cause of this kind of tinnitus is the conductive part of the auditory system is impaired, such as swelling of the external auditory canal, blockage, tympanic membrane perforation, invagination, inflammation of the middle ear, adhesion, sclerosis and so on. The impaired conduction reduces the ability to hear external sounds and diminishes its ability to mask the sounds occurring in the body so that they can be felt and become tinnitus. Further, the sound transmitted into the ear through the bone conduction, due to the conduction disorder, the outward escape channel is blocked, and improves the feeling of the sound in the ear, which becomes a low-frequency-based, wind-like whistling sound. We can try ourselves, with a hand over the ears, feel the roaring sound in the ear, this is a typical conductive tinnitus.
The third is neurological tinnitus. The reason is that the sensorineural part of the auditory system is impaired. When the inner ear auditory receptors have a disease, such as drug poisoning, noise trauma, Meniere's disease, etc.; auditory nerve and auditory center suffered trauma or inflammation, poisoning, ischemia, tumors, etc.; as well as a variety of intracranial lesions affecting the auditory nerve or auditory center, tinnitus will occur. This kind of tinnitus is mostly high-frequency cicatrization or piercing shrill. Some systemic diseases can also cause tinnitus, such as hypertension, hypotension, vegetative nerve dysfunction and so on and affect the blood supply, the effect of toxins of certain diseases, endocrine disorders caused by mental tension, anxiety and so on. In terms of life, poor rest, insomnia will also have tinnitus appear after. There are also some deafness, with the current medical technology conditions can not figure out its cause or in the clinical aspects of the examination is not clear, known as the cause of unknown tinnitus.
The fourth is objective tinnitus. Tinnitus is a subjective feeling, but there is a throbbing tinnitus can be heard by others, which is called objective tinnitus. This kind of tinnitus is different from subjective tinnitus, it does have a sound source, but the sound source is not in the outside world, but the body near my ear. One sound source is the middle ear within the small muscles or pharyngeal meatus contracture sound; another sound source is the sound of blood vessel pulsation. Under normal circumstances, the sound of blood vessel pulsation is not felt, but when the blood pressure rises pulsation sound increases, or to the outside to escape obstruction, or the occurrence of aneurysm or arteriovenous fistula and other diseases, blood vessel pulsation sound constitutes tinnitus