Along the path a hearing signal travels to get from the inner ear to the brain, there are many places where things can go wrong to cause tinnitus. If scientists can understand what goes on in the brain to start tinnitus and cause it to persist, they can look for those places in the system where a therapeutic intervention could stop tinnitus in its tracks.
It’s the same mechanism that’s happening in people who feel a phantom limb sensation after losing a limb, explains Susan Shore, PhD, a professor of otolaryngology, molecular physiology, and biomedical engineering at the University of Michigan in Ann Arbor. With tinnitus the loss of hearing causes specific brain neurons to increase their activity as a way of compensating, she explains. “These neurons also synchronize their activity as they would if there were a sound there, but there is no external sound,” she adds.
Note however that tinnitus nearly always consists of fairly simple sounds -- for example, hearing someone talking that no one else can hear would not ordinarily be called tinnitus -- this would be called an auditory hallucination. Musical hallucinations in patients without psychiatric disturbance is most often described in older persons, years after hearing loss.
An assessment of hyperacusis, a frequent accompaniment of tinnitus, may also be made. The measured parameter is Loudness Discomfort Level (LDL) in dB, the subjective level of acute discomfort at specified frequencies over the frequency range of hearing. This defines a dynamic range between the hearing threshold at that frequency and the loudnes discomfort level. A compressed dynamic range over a particular frequency range is associated with subjectve hyperacusis. Normal hearing threshold is generally defined as 0–20 decibels (dB). Normal loudness discomfort levels are 85–90+ dB, with some authorities citing 100 dB. A dynamic range of 55 dB or less is indicative of hyperacusis.
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.
According to the American Tinnitus Association, this complex audiological and neurological condition is experienced by nearly 50 million Americans. (2) Older adults, men, people who smoke or use drugs, and those with a history of ear infections or cardiovascular disease have the highest risk for developing tinnitus. Most experts believe that it’s not a disorder itself, but rather one symptom of another underlying disorder that affects auditory sensations and nerves near the ears. However, there are tinnitus treatment options out there to treat those symptoms.
Ototoxic drugs can also cause subjective tinnitus, as they may cause hearing loss, or increase the damage done by exposure to loud noise. Those damages can occur even at doses that are not considered ototoxic. Over 260 medications have been reported to cause tinnitus as a side effect. In many cases, however, no underlying cause could be identified.
Loud noise is the leading cause of damage to the inner ear. Most patients with noise trauma describe a whistling tinnitus (Nicholas-Puel et al,. 2002). In a large study of tinnitus, avoidance of occupational noise was one of two factors most important in preventing tinnitus (Sindhusake et al. 2003). The other important factor was the rapidity of treating ear infections.
There are eight main causes of tinnitus that when avoided or removed from your life can help improve your tinnitus dramatically. Ironically, these 8 causes do not affect everyone in the same way. Some people will have no reaction to some of these tinnitus causes, while others will have a severe reaction. There’s no clear answer to why this is, but the condition is a growing one with one in five individuals who reach the age of fifty-five suffering from tinnitus.
What does he mean by “ends up in the brain”? Essentially, something that causes even temporary hearing damage — such as exposure to very loud noise or a blow to the head — can change activity patterns in the brain in ways that cause the ringing. Even though some damage or problem in the ear triggered tinnitus to begin with, you continue to hear the sound you do because of a signal from the brain.
As a hearing healthcare provider, I regularly get asked about a cure for tinnitus. Trust me, if there was one, I would be using it! I have had tinnitus for more than seven years. It makes it hard to sleep, to concentrate, to read a book. Basically, anything that is normally done in quiet became a struggle for me. (To see how tinnitus is affecting you, take our free tinnitus test.)
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.
Temporomandibular joint (TMJ) syndrome is a disorder that causes symptoms like pain, clicking, and popping of the jaw. TMJ is caused by injury to the temporomandibular joint. Stress, poor posture, jaw trauma, genetic predisposition, and inflammatory disorders are risk factors for the condition. A variety of self-care measures (application of ice, use of over-the-counter pain medication, massage, relaxation techniques) and medical treatment options (dental splint, Botox, prescription medications, surgery) are available to manage TMJ. The prognosis of TMJ is good with proper treatment.
The exact biological process by which hearing loss is associated with tinnitus is still being investigated by researchers. However, we do know that the loss of certain sound frequencies leads to specific changes in how the brain processes sound. In short, as the brain receives less external stimuli around a specific frequency, it begins to adapt and change. Tinnitus may be the brain’s way of filling in the missing sound frequencies it no longer receives from the auditory system.
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.
Tinnitus can be caused by a variety of less common underlying conditions or injuries. If you have tinnitus, start your treatment path by seeking out a hearing healthcare professional who specializes in tinnitus diagnostics so they can help identify the underlying cause. If the common causes for tinnitus are ruled out, the practitioner will refer you to another specialist for further evaluation. Listed below are related medical specialties who might be able to help you determine the cause of your tinnitus.
Tinnitus can be triggered by a variety of different causes, and it varies dramatically from person to person. Some of the causes result in permanent tinnitus that may require treatment, while others result in temporary tinnitus that disappears on its own. Common causes of tinnitus include hearing loss, wax buildup, stress, exposure to loud noises, certain disorders, and certain medications. To learn more about the various causes of tinnitus, check out our page What Causes Tinnitus?
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.
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.
The yearlong Dutch trial gave adults with tinnitus a standard package of care or a programme which added cognitive behavioural therapy (CBT) to elements of standard therapy for tinnitus. CBT is a type of therapy that challenges people’s negative assumptions and feelings to help them overcome their worries. Compared with those given usual care, the group receiving specialised treatment reported improved quality of life, and reduced severity and impairment caused by tinnitus.
As their name suggests, maskers conceal tinnitus through other sounds. They look similar to hearing aids, but they won’t enhance your hearing. In this way, they’re like band-aids, covering up the problem instead of actually solving it. In addition, some people find maskers frustrating, because they can soften important sounds, like speech. We do not recommend maskers for long-term use as they do not work in re-wiring the brain.
To keep the brain activated and aware, Kilgard’s therapy involves stimulating the vagus nerve, which is actually a pair of nerves that runs inside the neck and into the brain. “All the stuff you brains learns about your body — it all comes in through the vagus nerve,” he says. “We trick the brain into thinking it’s learning something important by stimulating this nerve in the neck.”