The researchers next tested whether tinnitus could be reversed in noise-exposed rats. The animals received VNS paired with various tones other than the tinnitus frequency 300 times a day for about 3 weeks. Rats that received the treatment showed behavioral changes indicating that the ringing had stopped. Neural responses in the brain's auditory cortex returned to their normal levels as well, indicating that the tinnitus had disappeared.
Most people who seek medical help for tinnitus experience it as subjective, constant sound like constant ringing in the ears or a buzzing sound in the ear, and most have some degree of hearing loss. Things that cause hearing loss (and tinnitus) include loud noise, medications that damage the nerves in the ear (ototoxic drugs), impacted earwax, middle ear problems (such as infections and vascular tumors), and aging. Tinnitus can also be a symptom of Meniere's disease, a disorder of the balance mechanism in the inner ear.
The diagnosis of tinnitus is usually based on the person's description.[3] A number of questionnaires exist that may help to assess how much tinnitus is interfering with a person's life.[3] The diagnosis is commonly supported by an audiogram and a neurological examination.[1][3] If certain problems are found, medical imaging, such as with MRI, may be performed.[3] Other tests are suitable when tinnitus occurs with the same rhythm as the heartbeat.[3] Rarely, the sound may be heard by someone else using a stethoscope, in which case it is known as objective tinnitus.[3] Spontaneous otoacoustic emissions, which are sounds produced normally by the inner ear, may also occasionally result in tinnitus.[6]
A common cause of tinnitus is inner ear hair cell damage. Tiny, delicate hairs in your inner ear move in relation to the pressure of sound waves. This triggers cells to release an electrical signal through a nerve from your ear (auditory nerve) to your brain. Your brain interprets these signals as sound. If the hairs inside your inner ear are bent or broken, they can "leak" random electrical impulses to your brain, causing tinnitus.
