About 25-30 million Americans have tinnitus as a condition, and they experience these noises on a regular, most often daily, basis. About 40 percent of people with tinnitus hear tinnitus noise through 80 percent of their day. And for a smaller group of people—about 1 in 5, tinnitus is disruptive enough to significantly interfere with daily functioning, becoming disabling or nearly disabling.
Objective tinnitus is very rare. It can be heard by a doctor either using a stethoscope or by listening very closely to your ear. It occurs rarely and may due to involuntary muscle contractions or vascular deformities. The sound is often described as pulsating and may be heard in time with your heartbeat. Objective tinnitus usually has a determinable cause and disappears when treated by surgery or other medical intervention.
Tinnitus – a sound in the head with no external source – is not a disease; it is a symptom that can be triggered by a variety of different health conditions. So what causes tinnitus? Common sources include hearing loss, ear wax buildup, ototoxic medications, and ear bone changes. No matter what the cause, the condition interrupts the transmission of sound from the ear to the brain. Some part of the hearing system is involved as well, whether the outer, middle, or inner ear.
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.