Tinnitus emissions (SOAEs), which are faint high-frequency tones that are produced in the inner ear and can be measured in the ear canal with a sensitive microphone, may also cause tinnitus. About 8% of those with SOAEs and tinnitus have SOAE-linked tinnitus, while the percentage of all cases of tinnitus caused by SOAEs is estimated at about 4%. Some people experience a sound that beats in time with their pulse, known as "pulsatile tinnitus" or "vascular tinnitus". Pulsatile tinnitus is usually objective in nature, resulting from altered blood flow, increased blood turbulence near the ear, such as from atherosclerosis or venous
Tinnitus masker efficacy of a tinnitus masker may depend on the wearer's capacity to experience "residual inhibition," the temporary suppression of tinnitus in response to particular sound patterns. The mechanism of sound masking can be explained by analogy with light. In a dark room where someone is turning a lamp on and off, the light will be obviously noticeable. However if the overhead lights are turned on, turning on the lamp will no longer be as distracting because it has been "masked". The concept that an external sound could suppress perception of an internal one was first realised clinically in the mid