Tinnitus is when people think they hear something in their ears but there is actually no sound. People with tinnitus actually do "hear" noises that range from a whistle to a crackling noise to a roar. It can happen only occasionally, can occur for a period of days then take a break before recurring again, or it can be constant. The sound can vary in pitch from quiet to unbearably loud, or it can stay the same.
Tinnitus that's continuous, steady, and high-pitched (the most common type) generally indicates a problem in the auditory system and requires hearing tests conducted by an audiologist. Pulsatile tinnitus calls for a medical evaluation, especially if the noise is frequent or constant. MRI or CT imaging may be needed to check for a tumor or blood vessel abnormality.
Atherosclerosis. With age and buildup of cholesterol and other deposits, major blood vessels close to your middle and inner ear lose some of their elasticity — the ability to flex or expand slightly with each heartbeat. That causes blood flow to become more forceful, making it easier for your ear to detect the beats. You can generally hear this type of tinnitus in both ears.