Tinnitus is usually described as a ringing in the ears, but it can also sound like clicking, hissing, roaring, or buzzing. Tinnitus involves perceiving sound when no external noise is present. The sound can be very soft or very loud, and high-pitched or low-pitched. Some people hear it in one ear and others hear it in both. People with severe tinnitus may have problems hearing, working, or sleeping.
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.
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.
The majority of cases of tinnitus are subjective. Objective tinnitus is far less common. However, a diagnosis of objective tinnitus is tied to how hard and well the objective (outside) listener tries to hear the sound in question. Because of this problem, some clinicians now simply refer to tinnitus as either rhythmic or non-rhythmic. Generally, rhythmic tinnitus correlates with objective tinnitus and non-rhythmic tinnitus correlates with subjective tinnitus. Specific forms of tinnitus such as pulsatile tinnitus and muscular tinnitus, which are forms of rhythmic tinnitus, are relatively rare. Pulsatile tinnitus may also be known as pulse-synchronous tinnitus. Properly identifying and distinguishing these less common forms of tinnitus is important because the underlying cause of pulsatile or muscular tinnitus can often be identified and treated.
If the source of the problem remains unclear, you may be sent to an otologist or an otolaryngologist (both ear specialists) or an audiologist (a hearing specialist) for hearing and nerve tests. As part of your examination, you may be given a hearing test called an audiogram. An imaging technique, such as an MRI or a CT scan, may also be recommended to reveal any structural problem.
There's no known cure for tinnitus. Current treatments generally involve masking the sound or learning to ignore it. A research team led by Dr. Michael Kilgard at the University of Texas at Dallas and Dr. Navzer Engineer at MicroTransponder, Inc. set out to see if they could develop a way to reverse tinnitus by essentially resetting the brain's auditory system. Their work was funded in part by NIH’s National Institute on Deafness and Other Communication Disorders (NIDCD).
The results were calculated using a measure called “effect size”, which is a way of quantifying the size of the difference between the two groups. For the difference in quality of life scores between groups, the effect size was calculated to be 0.24. This can be interpreted as a “small” effect. In other words, treatment including CBT gave a small improvement in quality of life compared with usual care.