This document is not written for or intended for use in legal proceedings.
Tinnitus (pronounced "tin-it-tus") is an abnormal noise in the ear (note that it is not an "itis" -- which means inflammation). Tinnitus is common -- nearly 36 million Americans have constant tinnitus and more than half of the normal population has intermittent tinnitus. Another way to summarize this is that about 10-15% of the entire population has some type of constant tinnitus, and about 20% of these people (i.e. about 1% of the population) seek medical attention (Adjamian et al, 2009). Similar statistics are found in England (Dawes et al, 2014) and Korea (Park and Moon, 2014).
The prevalence of tinnitus depends on the questions you ask. Nemholt et al (2019) reported that the prevalence of "any tinnitus" was 66.9% in Danish children aged 10-16. We believe them -- it just shows you get what you ask for. This means that standardized questions are necessary to compare apples to apples.
About six percent of the general population has what they consider to be "severe" tinnitus. That is a gigantic number of people ! Tinnitus is more common with advancing age. In a large study of more than 2000 adults aged 50 and above, 30.3% reported having experienced tinnitus, with 48% reporting symptoms in both ears. Tinnitus had been present for at least 6 years in 50% of cases, and most (55%) reported a gradual onset. Tinnitus was described as mildly to extremely annoying by 67%.(Sindhusake et al. 2003)
Tinnitus can come and go, or be continuous. It can sound like a low roar, or a high pitched ring. Tinnitus may be in both ears or just in one ear. Seven million Americans are so severely affected that they cannot lead normal lives.
The most common types of tinnitus are ringing or hissing ringing, whistling (high pitched hissing) and roaring (low-pitched hissing). Some persons hear chirping, screeching, or even musical sounds.
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.
Another way of splitting up tinnitus is into objective and subjective. Objective tinnitus can be heard by the examiner. Subjective cannot. Practically, as there is only a tiny proportion of the population with objective tinnitus, this method of categorizing tinnitus is rarely of any help. It seems to us that it should be possible to separate out tinnitus into inner ear vs everything else using some of the large array of audiologic testing available today. For example, it would seem to us that tinnitus should intrinsically "mask" sounds of the same pitch, and that this could be quantified using procedures that are "tuned" to the tinnitus.
Epidemiology of Tinnitus:
|Distribution of Persons with tinnitus|
|Population||Percent with Tinnitus||Percent with Hearing Loss||Reference|
|"pediatric"||22%||Chan et al, 2017|
|Older than 50||20%||Moller, 2007|
|65-70||12%||35%||Adams et al, 1999|
With respect to incidence (the table above is about prevalence), Martinez et al (2015) reported that there were 5.4 new cases of tinnitus per 10,000 person-years in England. We don't find this statistic much use as tinnitus is highly prevalent in otherwise normal persons. It seems to us that their study is more about how many persons with tinnitus were detected by the health care system -- and that it is more a study of England's health care system than of tinnitus.
Chan et al (2017) compared pediatric to adult tinnitus, and stated that "This study distinguishes pediatric tinnitus from adult tinnitus in terms of lower association with underlying hearing loss, lower likelihood of reported anxiety, and higher likelihood of improvement and resolution. " So it is good to be young.
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.
Less commonly, tinnitus may be accompanied by hyperacusis (an abnormal sensitivity to sound).
|Structures of the ear. Most tinnitus is due to damage to the cochlea (#9 above)|
Henry et al (2005) reported that noise was an associated factor for 22% of cases, followed by head and neck injury (17%), infections and neck illness (10%), and drugs or other medical conditions (13%). The rest of their patients could not identify an event.
Park and Moon (2004) reported the odds ratio for tinnitus according to many factors. They examined results from 10,061 Koreans.
|Chronic otitis media||1.53|
Thus it can see that there are numerous factors that are weakly correlated with tinnitus, and that hearing impairment is the most strongly associated. It is surprising that TMJ's correlation is nearly as high as hearing impairment, and more than depression or stress. Other studies have similar results (Lee et al, 2016)
It is very well accepted that tinnitus often is "centralized" -- while it is usually initiated with an inner ear event, persistent tinnitus is associated with changes in central auditory processing (Adjamian et al, 2009). Sometimes this idea is used to put forth a "therapeutic nihilism" -- suggesting that fixing the "cause" -- i.e. inner ear disorder -- will not make the tinnitus go away. This to us seems overly simplistic -- while it is clear that the central nervous system participates in perception of sounds, and thus must be a participant in the "tinnitus" process, we think that it is implausible that in most cases that there is not an underlying "driver" for persistent tinnitus.
Supporting the idea that central reorganization is overestimated as "the" cause of tinnitus, a recent study by Wineland et al showed no changes in central connectivity of auditory cortex or other key cortical regions (Wineland et al, 2012). Considering other parts of the brain, Ueyama et al (2013) reported that there was increased fMRI activity in the bilateral rectus gyri, as well as cingulate gyri correlating with distress. Loudness was correlated with values in the thalamus, bilateral hippocampus and left caudate. In other words, the changes in the brain associated with tinnitus seem to be associated with emotional reaction (e.g. cingulate), and input systems (e.g. thalamus). There are a few areas whose role is not so obvious (e.g. caudate). This makes a more sense than the Wineland result, but of course, they were measuring different things. MRI studies related to audition or dizziness must be interpreted with great caution as the magnetic field of the MRI stimulates the inner ear, and because MRI scanners are noisy.
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.
Another way to look at it is to look at the areas of the body that can initiate tinnitus.
Most tinnitus comes from damage to the inner ear, specifically the cochlea (the snail like thing on the right of figure 1, labeled '9').
In pulsatile tinnitus, people hear something resembling their heartbeat in their ear. Click on the link above for more details.
In our opinion, people are very quick to blame drugs for their tinnitus, but it is rare that this is borne out.
Many medications also can cause tinnitus (see list below). Generally this is thought to arise from their effect on the cochlea (inner ear).
Drugs that commonly cause or increase tinnitus -- these are largely ototoxins.
- NSAIDS (motrin, naproxen, relafen, etc)
- aspirin and other salicylates
- Lasix and other "loop" diuretics
- "mycin" antibiotics such as vancomycin (but rarely macrolides such as azithromycin)
- quinine and related drugs
- Chemotherapy such as cis-platin
Antidepressants are occasionally associated with tinnitus (Robinson, 2007). For example, Tandon (1987) reported that 1% of those taking imiprimine complained of tinnitus. In a double-blind trial of paroxetine for tinnitus, 3% discontinued due to a perceived worsening of tinnitus (Robinson, 2007). There are case reports concerning tinnitus as a withdrawal symptom from Venlafaxine and sertraline (Robinson, 2007). In our clinical practice, we have occasionally encountered patients reporting worsening of tinnitus with an antidepressant, generally in the SSRI family.
Often people bring in very long lists of medications that have been reported, once or twice, to be associated with tinnitus. This unfortunate behavior makes it very hard to care for these patients -- as it puts one into an impossible situation where the patient is in great distress but is also unwilling to attempt any treatment. Specialists who care for patients with ear disease, usually know very well which drugs are problems (such as those noted above), and which ones are nearly always safe.
As tinnitus is essentially subjective, malingering of tinnitus as well as psychological causes of tinnitus is certainly possible. In fact, auditory hallucinations (such as hearing voices) are common in schizophrenia.
In malingering, a person claims to have tinnitus (or more tinnitus), in an attempt to gain some benefit (such as more money in a legal case). See this page concerning malingering of hearing symptoms.
There is a high correlation between anxiety depression and the annoyance/severity of tinnitus (Pinto et al, 2014).
Persons with tinnitus should be seen by a physician expert in ear disease, usually an otologist or a neurotologist.
There should be an examination of the ears with an otoscope. Wax should be removed, and the examiner should note whether the ear drum is intact, inflamed, scarred, or whether it is moving.
The eyes should be examined for papilloedema (swelling of a portion of the back of the eye called the "optic disk") as increased intracerebral pressure can cause tinnitus. Because papilloedema is so rare, and tinnitus is so common, it is very unusual to find this dangerous condition.
The TMJ joints of the jaw should be checked as about 28% of persons with TMJ syndrome experience tinnitus. TMJ is very common too.
Inspection of the eardrum may sometimes demonstrate subtle movements due to contraction of the tensor tympani (Cohen and Perez, 2003). Tensor tympani myoclonus causes a thumping. Another muscle, the stapedius, can also make higher pitched sounds. See this page for more. Opening or closing of the eustachian tube causes a clicking. The best way to hear "objective tinnitus" from the middle ear is simply to have an examiner with normal hearing put their ear up next to the patient. Stethoscopes favor low frequency sounds and may not be very helpful.
|Type of middle ear tinnitus||Sound||Ear Drum|
|Tensor tympani||Thump, inaudible to examiner||Indentation|
|Stapedius||Tick, can be heard by examiner||
|ETD||Click, can be heard by examiner||Nothing|
|Cartoon of the middle ear showing muscles that attach to ossicles (ear bones), and ear drum. The stapedius is attached to the stapes (of course -- horseshoe object above), while the tensor tympani is attached to the ear drum. While useful, be aware that there are multiple errors in this illustration from Loyola Medical School. With permission, from: http://www.meddean.luc.edu/lumen/meded/grossanatomy/dissector/mml/images/stap.jpg|
Based on tests, tinnitus can be separated into categories of cochlear, retrocochlear, central, and tinnitus of unknown cause.
Patients with tinnitus often undergo the tests listed above.
The audiogram sometimes shows a sensorineural deficit. This may be due to true loss of hearing, or due to masking from the tinnitus.
Tinnitus matching is helpful to identify the frequency and intensity of the tinnitus. This is a simple procedure in which the audiologist adjusts a sound until a patient indicates that it is the same as their tinnitus. Most patients match their tinnitus to the region of their hearing loss (Konig et al, 2006; Mahboubi et al, 2012). Unfortunately, the "gap detection test", does not work to confirm tinnitus in humabs (Boyen et al, 2015).
ABR (ABR) testing may show some subtle abnormalities in otherwise normal persons with tinnitus (Kehrle et al, 2008). The main use of ABR (ABR test) is to assist in diagnosing tinnitus due to a tumor of the 8th nerve or tinnitus due to a central process. A brain MRI is used for the same general purpose and covers far more territory, but is roughly 3 times more expensive. ABRs are generally not different between patients with tinnitus with or without hyperacusis (Shim et al, 2017).
The physician may also request an OAE test (which is very sensitive to noise induced hearing damage), an ECochG (looking for Meniere's disease and hydrops, an MRI/MRA test (scan of the brain), a VEMP (looking for damage to other parts of the ear) and several blood tests (ANA, B12, FTA, ESR, SMA-24, HBA-IC, fasting glucose, TSH, anti-microsomal antibodies).
We occasionally recommend neuropsychological testing using a simple screening questionnaire -- depression, anxiety, and OCD (obsessive compulsive disorder) are common in persons with tinnitus. This is not surprising considering how disturbing tinnitus may be to ones life (Holmes and Padgham, 2009). Persons with OCD tend to "obsess" about tinnitus. Treatment of these psychological conditions may be extremely helpful.
Branstetter and Weissman (2006) reviewed the radiological evaluation of tinnitus. They favor contrast-enhanced MRI to detect tumors of the inner ear area. Of course, tumors are a very rare cause of tinnitus, as tinnitus is at least 100 times more common than tumors of the inner ear area.
Causes that can be seen on radiological testing of continuous tinnitus include: (Branstetter and Weissman)
Microvascular compression of the 8th nerve is not a significant cause of tinnitus (Gultekin et al. 2008).
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.
A difficulty with most tinnitus is that it is subjective. Certainly one could pretend to have tinnitus, or claim to have more or less tinnitus than is true.
One would think that tinnitus would obscure perception of sound at the frequency of tinnitus, and thus be measurable through an internal masking procedure, but this approach has not been helpful.
Recent studies involving attempts to objectify tinnitus are below:
Holmes and Padgham (2009) reviewed the impact of tinnitus on persons lives. Severe tinnitus is associated with anxiety, distress, sleep disturbance, and sometimes depression.
Disrupted sleep is the most significant complaint, and affects between 25-50% of tinnitus patients.
Poor attention and concentration are commonly reported. About 42% of survey respondents reported that tinnitus interfered with their work.
Tinnitus often has negative effects on personal relationships.
We this is a big subject and we have split this material to another page on tinnitus treatment. Briefly, the algorithm that we use in our practice to diagnose and treat tinnitus is here (a PDF graphic). After a diagnostic step, there are many branch points involving treatment trials.
As of 6/2018, a visit to the National Library of Medicine's search engine, Pubmed, revealed more than 4,000 research articles with tinnitus in their title, published. In spite of this gigantic effort, very little is presently known about tinnitus, and effective treatment is generally unavailable.
Plein et al (2015) suggested that the quality of published studies concerning clinical trials for tinnitus were suboptimal, and in fact, only 20% of 147 had a low risk of bias. The author of this page feels happy that at least someone is doing trials on this difficult situation ! Any kind of trial is better than no effort at all.