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.
Cochlear Implants. These implants are a treatment option for patients that have a severe hearing loss along with tinnitus. Cochlear implants are designed to bypass any damaged parts of the inner ear and send the electrical signals sound makes directly to the auditory nerve. By bringing in outside noise, these implants can effectively mask your tinnitus, as well as stimulate your neural circuits to change.
A common cause of tinnitus is inner ear hair cell damage. Tiny, delicate hairs in your inner ear move in relation to the pressure of sound waves. This triggers cells to release an electrical signal through a nerve from your ear (auditory nerve) to your brain. Your brain interprets these signals as sound. If the hairs inside your inner ear are bent or broken, they can "leak" random electrical impulses to your brain, causing tinnitus.