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.
Between 2007 and 2011, the researchers recruited 492 Dutch adults who had been diagnosed with tinnitus. The patients had to fulfil several criteria, including having no underlying disease that was causing their tinnitus, no other health issues that precluded their participation, and to have received no treatment for their tinnitus in the five previous years. Some 66% of adults originally screened for the study participated after screening.
^ Jump up to: a b Schecklmann, Martin; Vielsmeier, Veronika; Steffens, Thomas; Landgrebe, Michael; Langguth, Berthold; Kleinjung, Tobias; Andersson, Gerhard (18 April 2012). "Relationship between Audiometric Slope and Tinnitus Pitch in Tinnitus Patients: Insights into the Mechanisms of Tinnitus Generation". PLOS One. 7 (4): e34878. Bibcode:2012PLoSO...734878S. doi:10.1371/journal.pone.0034878. PMC 3329543. PMID 22529949.
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.
A wealth of research has gone into understanding the mechanisms of tinnitus due to the increased concern in our ageing and noise exposed society through the support of organizations such as the Tinnitus Research Institute, the American Tinnitus Association and even the US Department of Defense. This research has helped us to understand not only why and how this phantom percept can develop, but also sheds light on why it may sound like a hiss for one person and a high pitched tone for another.7 In addition, neuroscientists have shown connections between the limbic system (where emotions are processed) and the auditory system; it is not uncommon for tinnitus to increase during times of stress or negative emotions.5 As such, the effective tinnitus treatment strategies should be enjoyable and positive, and should account for the variability in what tinnitus sounds like for each patient.
In persons with pulsatile tinnitus, additional tests maybe proposed to study the blood vessels and to check the pressure inside the head. Gentle pressure on the neck can be performed to block the jugular vein but not the carotid artery. The Valsalva maneuver reduces venous return by increasing intrathoracic pressure. If there is a venous hum, this usually abates or improves markedly. If the pulsation is arterial, these tests have no effect.
Some tinnitus sufferers have experienced relief through hearing aids, but studies indicate that such benefits are limited to those with low-frequency tinnitus.8 For those with a tinnitus pitch above 5–6 kHz or those with a hissing or buzzing tinnitus, the benefits of hearing aids are more limited or even nonexistent. This makes sense from a neuroscience point of view, as the hearing aid will typically not be making up for hearing loss at frequencies above 6–8 kHz; this prevents any possible effects on tinnitus types that are caused by changes to higher frequency regions in the auditory system. While hearing aids are essential to improving the lives of the hearing impaired, they are not typically the best option for tinnitus; especially when used alone.
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.