Although mitochondrial DNA variants are thought to predispose to hearing loss, a study of polish individuals by Lechowicz et al, reported that "there are no statistically significant differences in the prevalence of tinnitus and its characteristic features between HL patients with known HL mtDNA variants and the general Polish population." This would argue against mitochondrial DNA variants as a cause of tinnitus, but the situation might be different in other ethnic groups.
Most people who seek medical help for tinnitus experience it as subjective, constant sound like constant ringing in the ears or a buzzing sound in the ear, and most have some degree of hearing loss. Things that cause hearing loss (and tinnitus) include loud noise, medications that damage the nerves in the ear (ototoxic drugs), impacted earwax, middle ear problems (such as infections and vascular tumors), and aging. Tinnitus can also be a symptom of Meniere's disease, a disorder of the balance mechanism in the inner ear.
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.
Physical exam: Physical examination will focus on the head and neck, and especially the ears, including the auditory canals and tympanic membranes. Since the sense of hearing is conducted through one of the cranial nerves (the short nerves that lead directly from the brain to the face, head and neck), a careful neurologic exam also may be performed. Weakness or numbness in the face, mouth, and neck may be associated with a tumor or other structural abnormality pressing on a nerve. The healthcare professional may listen to the flow in the carotid arteries in the neck for an abnormal sound (bruit), since carotid artery stenosis (narrowing of the artery) can transmit a sound to the ear that may cause tinnitus.
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.