According to Tinnitus treatment expert, Tinnitus is the perception of sound in the absence of any real sound. These sounds are heard as periodic or constant noises. Ringing in the ears type noises are usually described as ringing, hissing, humming, buzzing, roaring, chirping or whistling. Tinnitus may be the result of hearing loss, sounds produced by adjacent structures, or other disease processes. While tinnitus has traditionally been thought to be produced in the ear, research has shown that tinnitus is produced by electrical activity in the brain (see the figure below or to the right).
To understand why this happens, we first have to explain how hearing works says tinnitus treatment specialist. See the figure below for the anatomy.
- Sound, which is transmitted as sound waves (vibration of the air), enters the ear canal and reaches the eardrum.
- The sound waves lead to the vibration of the eardrum, which also vibrates the small bones behind the ear drum.
- The vibration motion of the bones makes the fluid in the inner ear or cochlea to vibrate.
- The vibration waves in the inner ear fluid causes the sensory (hair) cells in the inner ear (cochlea) to bend. The hair cells change the movement into electrical signals.
- These electrical signals are transmitted through the hearing (auditory) nerve and up to the hearing part of the brain (auditory cortex), where they are interpreted.
In this way, the pitch (frequency) of a sound is translated to a physical space located in the inner ear. For this reason, we say that the cochlea is “tono-topically” organized, meaning that each spot in the inner ear picks up a certain pitch of sound say tinnitus treatment specialist. If you were to take the inner ear membrane and flatten it out, it would be organized exactly like the keyboard of a piano. This organization is maintained from the inner ear all the way up to the brain.
Tinnitus occurs when there is damage to the inner ear. Further, the “ringing” that we hear approximates to the region of the inner ear that is damaged. If the area of the inner ear that detects high pitch sounds is damaged (for example by loud noise exposure, aging, hereditary, or toxic reasons), we hear a high pitched “ringing”. When the damage corresponds to lower pitches, we hear a “buzz” or a “hum”. Interestingly, most people with tinnitus have a high pitch ringing because the area of the inner ear that detects high frequencies is closest to the middle ear, and is therefore more susceptible to damage from infection, noise damage, aging, and general wear and tear says Tinnitus therapy specialist.
There is one more important concept to understand about why tinnitus happens, and this one is the most counter-intuitive. It has to do with how the brain interprets signals coming from the inner ear. One would expect that when there is silence, the brain is not receiving signals from the inner ear. This is actually not the case. Instead, the brain receives a constant and steady source of information from all areas of the inner ear. The way that the brain interprets sound is by picking up increases in this steady state of background activity in the hearing areas of the brain.