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.
The researchers next tested whether tinnitus could be reversed in noise-exposed rats. The animals received VNS paired with various tones other than the tinnitus frequency 300 times a day for about 3 weeks. Rats that received the treatment showed behavioral changes indicating that the ringing had stopped. Neural responses in the brain's auditory cortex returned to their normal levels as well, indicating that the tinnitus had disappeared.
Acoustic neural stimulation is a relatively new technique for people whose tinnitus is very loud or won’t go away. It uses a palm-sized device and headphones to deliver a broadband acoustic signal embedded in music. The treatment helps stimulate change in the neural circuits in the brain, which eventually desensitizes you to the tinnitus. The device has been shown to be effective in reducing or eliminating tinnitus in a significant number of study volunteers.
Superior semicircular canal dehiscence syndrome is another not uncommon cause of pulsatile tinnitus. The superior semicircular canal is one of three canals found in the vestibular apparatus of the inner ear. The vestibular apparatus helps to maintain equilibrium and balance. In this syndrome, a part of the temporal bone that overlies the superior semicircular canal is abnormally thin or absent. Superior semicircular canal dehiscence syndrome can affect both hearing and balance to different degrees.
^ Jump up to: a b c Han BI, Lee HW, Kim TY, Lim JS, Shin KS (March 2009). "Tinnitus: characteristics, causes, mechanisms, and treatments". Journal of Clinical Neurology. 5 (1): 11–19. doi:10.3988/jcn.2009.5.1.11. PMC 2686891. PMID 19513328. About 75% of new cases are related to emotional stress as the trigger factor rather than to precipitants involving cochlear lesions.
Tinnitus is the perception of sound when no actual external noise or sound is present. It is often referred to as “ringing” in the ears. I have even heard some people call it “head noises.” While ringing sounds are very common, many people will describe the sound they hear as buzzing, hissing, whistling, swooshing, and clicking. In some rare cases, tinnitus patients report hearing music. I hear about 2,000 crickets all going at once!
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.
The degree of loudness or annoyance caused by tinnitus varies greatly from one individual to another. Loudness and annoyance do not always covary. An individual with loud tinnitus may not be troubled, while an individual with soft tinnitus may be debilitated. Most individuals with subjective tinnitus have hearing loss that shows up in a standard clinical audiogram. Tinnitus can sometimes worsen or sometimes improve over time.
Pulsatile tinnitus: This problem usually is related to blood flow, either through normal or abnormal blood vessels near the ear. Causes of pulsatile tinnitus include pregnancy, anemia (lack of blood cells), overactive thyroid, or tumors involving blood vessels near the ear. Pulsatile tinnitus also can be caused by a condition known as benign intracranial hypertension (an increase in the pressure of the fluid surrounding the brain).
Tinnitus is a ringing, buzzing, hissing, swishing, clicking, or other type of noise that seems to originate in the ear or head. Most of us will experience tinnitus or sounds in the ears at some time or another. According to the National Institute on Deafness and Other Communication Disorders (NIDCD), about 10% of adults in the U.S. - nearly 25 million Americans - have experienced tinnitus lasting at least five minutes in the past year. Tinnitus is identified more frequently in white individuals, and the prevalence of tinnitus in the U.S. is almost twice as frequent in the South as in the Northeast.
Other potential sources of the sounds normally associated with tinnitus should be ruled out. For instance, two recognized sources of high-pitched sounds might be electromagnetic fields common in modern wiring and various sound signal transmissions. A common and often misdiagnosed condition that mimics tinnitus is radio frequency (RF) hearing, in which subjects have been tested and found to hear high-pitched transmission frequencies that sound similar to tinnitus.
Some patients choose to get involved in “tinnitus retraining,” which involves wearing a device in the ears that provides soothing music or noise, along with undergoing counseling. The goal is to help your body and brain learn to get accustomed to tinnitus noise, which reduces your negative reactions to unwanted sounds. Support and counseling during the process can be helpful for reducing anxiety. Researchers are now learning more about the benefits of coherent cognitive behavioral therapy interventions to help treat distress associated with tinnitus. (3)
Most of the causes of tinnitus alter neurological activity within the auditory cortex, the portion of the brain responsible for hearing. The transmission of sound is interrupted, so some of the neural circuits fail to receive signals. Instead of causing hearing loss, as you might expect due to the lack of stimulation, the neural circuits begin chattering. First, they chatter alone. Then, they become hyperactive and synchronous. When we experience this deviation, our brains attempt to compensate for the change by interpreting the neurological activity as sound. This can resemble ringing, buzzing, hissing, whistling, or roaring, amongst a variety of other noises.
Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.
Tinnitus that's continuous, steady, and high-pitched (the most common type) generally indicates a problem in the auditory system and requires hearing tests conducted by an audiologist. Pulsatile tinnitus calls for a medical evaluation, especially if the noise is frequent or constant. MRI or CT imaging may be needed to check for a tumor or blood vessel abnormality.
Although there’s no proven cure for tinnitus, there are treatments that help make it easier to ignore. For example, you can wear devices in your ear(s) that produce soothing therapeutic noises to shift your focus away from the tinnitus. Other devices produce constant, soft noise to mask the tinnitus. Tinnitus sufferers who also have hearing loss sometimes find relief simply by wearing properly fitted hearing aids.