Most of the causes of tinnitus alter neurological activity within the auditory cortex, the portion of the brain responsible for hearing. The transmission of sound is interrupted, so some of the neural circuits fail to receive signals. Instead of causing hearing loss, as you might expect due to the lack of stimulation, the neural circuits begin chattering. First, they chatter alone. Then, they become hyperactive and synchronous. When we experience this deviation, our brains attempt to compensate for the change by interpreting the neurological activity as sound. This can resemble ringing, buzzing, hissing, whistling, or roaring, amongst a variety of other noises.
Most tinnitus is "sensorineural," meaning that it's due to hearing loss at the cochlea or cochlear nerve level. But tinnitus may originate in other places. Our bodies normally produce sounds (called somatic sounds) that we usually don't notice because we are listening to external sounds. Anything that blocks normal hearing can bring somatic sounds to our attention. For example, you may get head noise when earwax blocks the outer ear.
Unfortunately that means tinnitus is a very complicated condition that involves several systems of the body. The good news, though, is that as doctors and researchers have developed a better understanding of the mechanisms behind tinnitus, they’ve also been able to develop new and promising treatments that target the brain rather than the ear — and have more of a chance of actually reversing the problem.
Steven Doerr, MD, is a U.S. board-certified Emergency Medicine Physician. Dr. Doerr received his undergraduate degree in Spanish from the University of Colorado at Boulder. He graduated with his Medical Degree from the University Of Colorado Health Sciences Center in Denver, Colorado in 1998 and completed his residency training in Emergency Medicine from Denver Health Medical Center in Denver, Colorado in 2002, where he also served as Chief Resident.
Tinnitus habituation therapies, such as tinnitus retraining therapy (TRT), involve using low level sounds in a graduated fashion to decrease the perception of tinnitus. This differs from use of masking devices such as described earlier. TRT involves a wearable device that an affected individual can adjust so that the level of sound emitting from the device is about equal to or matches the tinnitus sound. This may be called the “mixing point” because the sound from the device and the tinnitus sound begin to mix together. An affected individual must repeatedly adjust the device so that the sound is at or just below the mixing point. TRT is supported by counseling with a trained professional who can teach the individual the proper techniques to maximize the effectiveness of TRT. Eventually, by following this method, affected individuals no longer need the external sound generating device. Affected individuals will become accustomed to the tinnitus sound (habituation), except when they choose to focus on it. Even then the sound will not be bothersome or troubling. The theory is akin to a person’s ability to ignore sounds such as the hum of air conditioner, the refrigerator motor turning on, or raindrops falling on the roof when driving a car in the rain.
Hair cells can be damaged by exposure to loud noise, which could lead to tinnitus. This can occur gradually as a result of exposure to noises over prolonged periods or may be caused by exposure to louder noises over a shorter period of time. If you are exposed to loud noises, you should always wear ear protection. Find out more about the subject on our How Loud Is Loud article and see if your job or lifestyle could be putting your ears at risk,
People with warning signs should see a doctor right away. People without warning signs in whom tinnitus recently developed should call their doctor, as should people with pulsatile tinnitus. Most people with tinnitus and no warning signs have had tinnitus for a long time. They can discuss the matter with their doctor and be seen at a mutually convenient time.
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.