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.
Repeated loud noise exposure can be a cause of tinnitus as well as hearing loss. Loud music may cause short term symptoms, but repeated occupational exposure (for example, musicians, factory and construction workers) requires less intense sound levels to cause potential hearing damage leading to tinnitus. Minimizing sound exposure, therefore, decreases the risk of developing tinnitus. Sound protection equipment, like acoustic ear-muffs, may be appropriate at work and at home when exposed to loud noises.
Assessment of psychological processes related to tinnitus involves measurement of tinnitus severity and distress (i.e., nature and extent of tinnitus-related problems), measured subjectively by validated self-report tinnitus questionnaires. These questionnaires measure the degree of psychological distress and handicap associated with tinnitus, including effects on hearing, lifestyle, health and emotional functioning. A broader assessment of general functioning, such as levels of anxiety, depression, stress, life stressors and sleep difficulties, is also important in the assessment of tinnitus due to higher risk of negative well-being across these areas, which may be affected by or exacerbate the tinnitus symptoms for the individual. Overall, current assessment measures are aimed to identify individual levels of distress and interference, coping responses and perceptions of tinnitus in order to inform treatment and monitor progress. However, wide variability, inconsistencies and lack of consensus regarding assessment methodology are evidenced in the literature, limiting comparison of treatment effectiveness. Developed to guide diagnosis or classify severity, most tinnitus questionnaires have been shown to be treatment-sensitive outcome measures.
Tinnitus can arise anywhere along the auditory pathway, from the outer ear through the middle and inner ear to the brain's auditory cortex, where it's thought to be encoded (in a sense, imprinted). One of the most common causes of tinnitus is damage to the hair cells in the cochlea (see "Auditory pathways and tinnitus"). These cells help transform sound waves into nerve signals. If the auditory pathways or circuits in the brain don't receive the signals they're expecting from the cochlea, the brain in effect "turns up the gain" on those pathways in an effort to detect the signal — in much the same way that you turn up the volume on a car radio when you're trying to find a station's signal. The resulting electrical noise takes the form of tinnitus — a sound that is high-pitched if hearing loss is in the high-frequency range and low-pitched if it's in the low-frequency range. This kind of tinnitus resembles phantom limb pain in an amputee — the brain is producing abnormal nerve signals to compensate for missing input.
Paquette et al (2017) reported a prospective study of 166 patients who had brain surgery involving removal of the medial temporal lobe. The prevalence of tinnitus increased from approximately from 10 to 20% post surgery. This study did not include a control -- a natural question would be -- suppose a different part of the brain were removed. One would also think that drilling of the skull from any source might increase tinnitus. We are presently dubious that the medial temporal lobe suppresses tinnitus.
Other causes of tinnitus include middle ear infections, disorders that block the ear canal (such as an external ear infection [external otitis], excessive ear wax, or foreign bodies), problems with the eustachian tube (which connects the middle ear and the back of the nose) due to allergies or other causes of obstruction, otosclerosis (a disorder of excess bone growth in the middle ear), and temporomandibular disorders. An uncommon but serious cause is an acoustic neuroma, a noncancerous (benign) tumor of part of the nerve leading from the inner ear.
Exposure to loud noise. Loud noises, such as those from heavy equipment, chain saws and firearms, are common sources of noise-related hearing loss. Portable music devices, such as MP3 players or iPods, also can cause noise-related hearing loss if played loudly for long periods. Tinnitus caused by short-term exposure, such as attending a loud concert, usually goes away; both short- and long-term exposure to loud sound can cause permanent damage.