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.
Individuals were recruited from within and around Hamilton, Ontario via online announcements and audiology clinics. Applicants were initially interviewed via telephone to screen for all inclusion and exclusion criteria for the study in order to determine whether they qualified for on-site screening. The on-site screening, and characterization of participants’ hearing thresholds and tinnitus profiles were conducted in a lab at McMaster University using a computer-based tinnitus assessment tool. Participants were randomly allocated to the treatment or placebo-control group. The assignment of the treatment or placebo music package was completed by a distributor site independent of the research study site. Participants and research personnel were blinded to which music package the participants received.
Now make your toes as tight as you can, really scrunch them up. Hold them like this for a moment – and relax. Now do the same with your ankles, then your calf muscles, your thighs… work all the way up your body to your head, making sure you tense, hold for a moment, and then release the tension. Once you’ve done this with your whole body, focus again on your breathing – notice the rhythm, it should be even and calm.
No matter what the cause, the condition interrupts the transmission of sound from the ear to the brain. Some of the neural circuits no longer receive signals. Strangely, this does not cause hearing loss. Instead, when neural circuits don’t receive stimulation, they react by chattering together, alone at first and then synchronous with each other. Once the nerve cells become hyperactive and occur at the same time, they simulate a tone the brain “hears” as tinnitus. Analogous to a piano, the broken “keys” create a permanent tone without a pianist playing the keys.
Ringing-in-the-ears or a fullness-of-the-head sensation are the most common symptoms of tinnitus. While ringing is the most common experience, the noise can also sound like a buzzing, hissing or whizzing sound. It can range from a low pitch to a high pitch and may be soft or loud at times. For some, tinnitus seems to get louder at night, just before sleep when no other sounds are competing with it. Tinnitus can remain constant or come and go intermittently. In severe cases, the ringing in the ears is loud enough to interfere with work or daily activity, whereas those with mild tinnitus can experience soft ringing that is no more than a minor annoyance.