When we hear, sound waves travel through the ear into the cochlea, our hearing organ in the inner ear. The cochlea is lined with thousands of tiny sound-sensing cells called hair cells. These hair cells change the sound waves into electrical signals. The hearing nerve then sends these electrical signals to the hearing part of the brain, which analyses them and recognises them as sound.
When there does not seem to be a connection with a disorder of the inner ear or auditory nerve, the tinnitus is called nonotic (i.e. not otic). In some 30% of tinnitus cases, the tinnitus is influenced by the somatosensory system, for instance people can increase or decrease their tinnitus by moving their face, head, or neck. This type is called somatic or craniocervical tinnitus, since it is only head or neck movements that have an effect.
Most tinnitus is "sensorineural," meaning that it's due to hearing loss at the cochlea or cochlear nerve level. But tinnitus may originate in other places. Our bodies normally produce sounds (called somatic sounds) that we usually don't notice because we are listening to external sounds. Anything that blocks normal hearing can bring somatic sounds to our attention. For example, you may get head noise when earwax blocks the outer ear.
It is important to note that existing hearing loss is sometimes not directly observable by the patient, who may not perceive any lost frequencies. But this this does not mean that hearing damage has not been done. A trained audiologist or other hearing health professional can perform sensitive audiometric tests to precisely measure the true extent of hearing loss.
Tinnitus sufferers most often cite stress as the cause of their condition. While it’s true noises are perceived more acutely when you are tense, there is no scientific basis for saying stress causes tinnitus. But the reverse is definitely true — hearing a constant noise in your ears can certainly cause stress and anxiety, and even lead to depression in some cases.
Most people with tinnitus also have hearing loss. Hence, hearing aids can be an effective part of any sound therapy. Hearing aids alone can provide partial or total relief from tinnitus. If you’re experiencing challenges with your hearing as well as tinnitus, a combination of a hearing solution with built-in sound generators can often be prescribed. You can expect improved levels of hearing which also helps to minimise the effects of the condition in the same way that sound therapy might.
Cochlear implants are sometimes used in people who have tinnitus along with severe hearing loss. A cochlear implant bypasses the damaged portion of the inner ear and sends electrical signals that directly stimulate the auditory nerve. The device brings in outside sounds that help mask tinnitus and stimulate change in the neural circuits. Read the NIDCD fact sheet Cochlear Implants for more information.
Age-Related Hearing Loss: Also known as presbycusis, age-related hearing loss results from the cumulative effect of aging on hearing. This permanent, progressive, and sensorineural condition is most pronounced at higher frequencies. It commonly impacts people over the age of 50, as all people begin to lose approximately 0.5% of the inner ear’s hair cells annually starting at age 40.
This personalized solution offers a selection of tinnitus relief sounds to support common management approaches. The flexible programming provides sound stimulation through select auditory options that can ease the effects of tinnitus. The sounds offer a variety of customized options and are used in conjunction with tinnitus retraining therapy to provide instructional counseling.
Another example of somatic tinnitus is that caused by temperomandibular joint disorder. The temporomandibular joint (TMJ) is where the lower jaw connects to the skull, and is located in front of the ears. Damage to the muscles, ligaments, or cartilage in the TMJ can lead to tinnitus symptoms. The TMJ is adjacent to the auditory system and shares some ligaments and nerve connections with structures in the middle ear.
It’s been found that exposure to very loud noises can contribute to early hearing loss and ear problems. Loud sounds can include those from heavy machinery or construction equipment (such as sledge hammers, chain saws and firearms). Even gun shots, car accidents, or very loud concerts and events can trigger acute tinnitus, although this should go away within a couple days in some cases. (5)
Tinnitus is commonly accompanied by hearing loss, and roughly 90% of persons with chronic tinnitus have some form of hearing loss (Davis and Rafaie, 2000; Lockwood et al, 2002). On the other hand, only about 30-40% of persons with hearing loss develop tinnitus. According to Park and Moon (2004), hearing impairment roughly doubles the odds of having tinnitus, and triples the odds of having annoying tinnitus.
Hyperactivity and deep brain stimulation. Researchers have observed hyperactivity in neural networks after exposing the ear to intense noise. Understanding specifically where in the brain this hyperactivity begins and how it spreads to other areas could lead to treatments that use deep brain stimulation to calm the neural networks and reduce tinnitus.
Hearing loss: Probably the most common cause for tinnitus is hearing loss. As we age, or because of trauma to the ear (through noise, drugs, or chemicals), the portion of the ear that allows us to hear, the cochlea, becomes damaged. Current theories suggest that because the cochlea is no longer sending the normal signals to the brain, the brain becomes confused and essentially develops its own noise to make up for the lack of normal sound signals. This then is interpreted as a sound, tinnitus. This tinnitus can be made worse by anything that makes our hearing worse, such as ear infections or excess wax in the ear.
Take medication for a thyroid disorder, if necessary. Tinnitus can be related to both hyperthyroidism, or an overactive thyroid, and hypothyroidism, or an underactive thyroid. Your doctor can check for swelling or lumps in your thyroid gland, which is in your throat, and order blood screens to test its function. If they find an issue, they’ll prescribe medication to regulate your thyroid hormone levels.
Some patients question the value of treatments that fall short of an absolute cure. ATA believes patients should do everything possible to lessen the burden of tinnitus until a definitive cure is found. An appropriate analogy may be the use of ibuprofen for a headache. Ibuprofen itself does not cure the underlying cause of most headaches, but it does reduce the pain that makes headaches feel so awful. Likewise, the most effective tinnitus treatment tools address the aspects of tinnitus that so often make the condition feel burdensome: anxiety, stress, social isolation, sound sensitivity, hearing difficulties, and perceived volume.
Tinnitus remains a symptom that affects the lives of millions of people. Research is directed not only at its treatment, but also at understanding why it occurs. Research by doctors at the University at Buffalo, The State University of New York, Dalhousie University (Canada), and Southeast China University have published research using electrophysiology and functional MRI to better understand what parts of the brain are involved in hearing and the production of tinnitus. Their research has found that much larger areas of the brain are involved with the process of hearing than previously believed, which may help direct future diagnostic and therapeutic options.
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.