Tinnitus

Tinnitus is the sensation of hearing a sound, such as a ringing or roaring, that does not come from your surroundings (nobody else can hear it). The sound may be continuous or intermittent, or it may keep time with your heartbeat. To the person affected with tinnitus, the sound seems to come from one ear or from somewhere in the head. In rare cases, clicking or crackling sounds in the ear can be heard by the doctor as well as by the person with tinnitus.

Normal sounds that come from your surroundings are "heard" when sound waves strike the eardrum. The eardrum vibrates, and those vibrations enter the inner ear, where they stimulate nerve cells to create signals that travel along the acoustic nerve to the brain. The brain then translates the signals into patterns that you recognize as sounds.

Tinnitus occurs when there is no external source of sound waves. For reasons that are not understood, the brain receives signals, either from inside the head or from within the ear, that cause the sensation of hearing a sound.

Tinnitus is most noticeable (and bothersome) when the affected person is in a quiet environment. The condition is often treated by using background noise to mask the ringing or roaring caused by tinnitus.