From: Eur Arch Otorhinolaryngol. 2011 Dec 23. [Epub ahead of print]

Tinnitus has been defined as a phantom auditory perception. Research indicates the necessity to make a distinction between the physical symptom and the subjective severity of the tinnitus symptom, since especially the latter seems to vary among patients. The relationship between tinnitus severity and psychological variables has been well established. Anxiety is considered to be an important variable for understanding the differences in the subjective tinnitus severity. Although many studies confirm the relationship between anxiety and tinnitus severity, most studies do not take the possibility of shared method variance and content overlap between questionnaires into account. Furthermore, anxiety is a broad concept and contains both a cognitive and somatic dimension.

Research including both dimensions of anxiety in tinnitus population is rare. According to the authors two conditions must be fulfilled before theorization on the relation is useful: (1) the presence of clinically relevant cognitive and/or somatic anxiety, (2) evidence of a substantial or “real” relationship. In this sample, almost 60% reported more than average cognitive anxiety and 40.8% reported clinical relevant somatic anxiety. After controlling for content overlap between the questionnaires used, the relation between tinnitus severity and cognitive and somatic anxiety remains significant. Two hypothetical models concerning this relationship that deserve future research attention are described in this article.

Tinnitus is a common problem in the population. With the aging of the population, the prevalence of tinnitus will increase. The prevention of tinnitus should focus on hearing impairment screening, otitis media treatment, and noise exposure reduction.

From: PLoS One. 2011;6(11):e27379

Tinnitus is the perception of sound in the absence of an auditory stimulus. Averaged over all age groups 5–15% of the western population experience some form of tinnitus. Many people can cope with chronic tinnitus, but about 1–2% of the population experience significant impairments in their quality of life due to their tinnitus.

The prevalence of chronic tinnitus increases with increasing age, peaking at 14.3% in people between 60 and 69 years of age. The increase in tinnitus prevalence with age is at least partly explained by the fact that hearing loss is an important risk factor for tinnitus and hearing loss prevalence also increases with age.

Neuroplastic processes play a crucial role both in the generation of tinnitus and in the amount of suffering. Imaging studies reveal that neuroplastic changes in the central auditory system are generating the tinnitus percept and that coactivation of nonauditory structures in the frontal cortex and the limbic system are involved in tinnitus related distress.

Studies in animals and humans have shown that the mechanisms of cortical plasticity change over the lifetime with a tendency of decreased and less efficient neuroplastic potential as demonstrated by decreased induction and maintenance of long-term-potentiation and reduced long-term depression-like effects with advancing age.

With these changes in the neuroplastic potential across the life span, age may not only have an influence on the incidence of tinnitus, but also on tinnitus related distress. A first hint for such a relation is given by a large epidemiological study demonstrating that people with bothersome tinnitus are elder than those with non-bothersome tinnitus. Considering that tinnitus duration also influences its annoyance the authors focused here especially on the role of tinnitus onset. In detail the authors hypothesized that the age of tinnitus onset may influence the perceived tinnitus related distress. More specifically, they assumed that early tinnitus onset is associated with less distress than later tinnitus onset.

The main finding of this analysis is an influence of the age at tinnitus onset on tinnitus related distress. Higher age at tinnitus onset is associated with higher tinnitus related distress. To the authors knowledge this is the first report about an influence of age of tinnitus onset on tinnitus severity. This effect is independent from the age at tinnitus assessment, the duration of tinnitus and the type of tinnitus onset (gradual versus abrupt).

A large variety of different variables have been identified in the past as contributing factors to tinnitus distress, among them tinnitus loudness, hearing loss, vertigo/dizziness, hyperacusis, depression, anxiety and personality factors. This study adds “age of onset” as an additional influencing factor underscoring the relevance of time related aspects in the pathophysiology of tinnitus. Earlier studies identified age and tinnitus duration as relevant factors. Age is strongly influencing tinnitus prevalence and tinnitus duration plays an important role for response to treatment. Though the effect of age of onset is statistically highly significant, it is rather small. However, considering the many variables, which exert a known influence on tinnitus related distress, this is not surprising.

Even though we cannot derive direct implications of the results on the clinical management of tinnitus patients, they may be relevant for a better understanding of both physiologic changes of brain function with increasing age and the pathophysiologic mechanisms involved in the generation of tinnitus distress. Many aspects of brain structure, brain function and brain plasticity are changing with age in a complex way. These changes also involve adaptive and compensatory neural mechanisms. Both the generation of tinnitus and the amount of tinnitus distress are thought to depend on adaptive and compensatory brain mechanisms. In this context higher tinnitus distress at higher age of onset suggests an age-related decline in the efficiency of this compensatory mechanism for tinnitus. Thus the finding is in line with the observation that a decrease of cognition is related to higher tinnitus related distress. Future studies are invited to further characterize the interactions between age related changes in neuroplastic potential, cognitive function and their influence on tinnitus distress.

Tinnitus related distress is influenced by many variables such as tinnitus loudness, hearing loss, vertigo/dizziness, hyperacusis, depression, anxiety and personality factors. Here the authors suggest that the age at tinnitus onset might be an additional factor. Patients with a later onset of tinnitus in their life report greater distress than patients with an early tinnitus onset. The decline of neuroplasticity with advancing age might be an underlying mechanism for this observation.

From: Curr Med Res Opin. 2011 Jun 23. [Epub ahead of print]

About 10% of the population experiences tinnitus, a common and distressing symptom characterized by the perception of sound in the absence of external stimuli. There is, however, marked heterogeneity in etiology, perception, and extent of distress among those who experience tinnitus. Reactions to tinnitus vary from simple awareness to severe irritation; some people have difficulty in hearing because of the loudness of the noise. Severe tinnitus causes many, often psychological, symptoms (e.g., tension, frustration, impaired concentration, disrupted sleep). For some, tinnitus is temporary, for others it is longstanding. Although many people adjust successfully, others are disabled by tinnitus; approximately 5% experience persistent and severe symptoms affecting their lifestyle and significantly reducing their quality of life. Because tinnitus is poorly understood and no single therapeutic approach is effective for all patients, many patients are told that ”nothing can be done” and they must ”learn to live with it.”

Tinnitus, often referred to as ‘ringing in the ears’, is highly prevalent. However, patients may also present with a number of other symptoms.

To review the broad range of symptoms of tinnitus, to evaluate their impact on patient quality of life and to explore methods of diagnosis and assessment. An electronic literature search was performed in PubMed between September and December 2010.

Accumulating evidence suggests that the symptoms of tinnitus are not confined to the characteristic ‘ringing in the ears’, but instead encompass wide-ranging symptoms that include emotional components such as sleep disturbance, anxiety, depression, irritation, and concentration difficulties.

Patients with tinnitus experience a spectrum of distressing symptoms that impact their quality of life and there is a clear need for action. Clinicians need to recognize and diagnose tinnitus that occurs with other wide-ranging symptoms to ensure that these symptoms are identified and patients receive effective treatment.

Tinnitus, a widespread, often intractable condition, affects millions of people; there is considerable debate about its causes. Tinnitus is distressing and may be severe enough to affect lifestyle and quality of life. Affected patients need considerable support and advice on healthcare options, encouragement to try different treatments and recognition that help and hope are available. Though patients may have to learn to live with tinnitus, the most important thing is that they recognise that help is available.

Recently, in Tinnitus in elderly patients and prognosis of mild-to-moderate congestive heart failure: a cross-sectional study with a long-term extension of the clinical follow-up, BMC Medicine 2011, 9:80,

Tinnitus is the perception of a sound that cannot be attributed to an external source. It is a nonspecific symptom generally referable to a largely unknown dysfunction of the hearing system. A comprehensive definition has been proposed to differentiate normal ear noises from pathological tinnitus defined as a head noise lasting at least five minutes and that occurs more than once per week. A distinction can also be made between subjective and objective tinnitus. The former is more common and refers to an individual sound that is perceived only by the patient. From the epidemiological point of view, tinnitus affects a remarkable number of adults and is frequently associated with a hearing loss of various degrees as expression of a cochlear disorder.

In the United Kingdom approximately 4.7 million of patients are affected by tinnitus and about 5% of them have experienced a severe and persistent disorder that affects their quality of life. The American Tinnitus Association has reported a prevalence of about 19% (37 to 40 million), which increases with age and the degree of hearing impairment. The prevalence of tinnitus has been reported to be higher in men than in women, and this difference might be related to higher hearing thresholds in the male population. Interestingly, only 1% of patients under 45 years of age experience tinnitus, while the prevalence is about 12% in those 60 to 69 years of age and 25 to 30% in those who are >70. Similar data recently have also been reported in a large cross-sectional study carried out with participants in the 1999 to 2004 US National Health and Nutrition Examination Surveys.

Several anatomical regions could contribute to the generation of tinnitus, even if a causative relationship between neurophysiological functions and tinnitus generation has not yet been demonstrated. Moreover, several pathophysiological hypotheses have recently been proposed to explain the genesis of different kinds of tinnitus: from genetic to iatrogenic, from neurological to vascular. However, a final and unique explanation is not actually available. In this complex scenario, tinnitus associated clinical conditions, such as vascular diseases, middle ear diseases, diabetes, hypertension, autoimmune disorders, and degenerative neural disorders with or without concomitant hearing loss, a functional component leading to an impaired regulation of the peripheral vascular tone can be demonstrated.

For that reason, at least partly, tinnitus could be the expression of a circulatory impairment of the microcirculation of the inner ear resulting from a detrimental feedback loop between the control of systemic blood pressure and the reflex activation of the neurohumoral system (for example, sympathetic nervous system and renin-angiotensinaldosterone system. Accordingly, any clinical condition leading to a reduction in systemic and/or regional blood flow at the ear level can trigger the onset of tinnitus or promote its exacerbation in patients already affected by this disorder.

Chronic heart failure could be an ideal biological model to test the vascular disregulatory hypothesis of tinnitus since it is often associated with a reduced cardiac output, as well as with a reflex activation of vasoconstrictive systems, including the sympathetic nervous system and RAAS. The prevalence of chronic heart failure is significantly increased in the elderly population, who also have a higher rate of tinnitus and afford researchers with a reliable clinical setting to investigate the circulatory origin of hearing disorders.

To date, this is the first large, cross-sectional, clinical study supporting an association between tinnitus and chronic heart failure control in elderly patients. Data suggest that the onset of tinnitus might be affected by the degree of decline in LV function and is probably the consequence of an insufficient autoregulatory mechanism at the level of the circulation of the inner ear. These data can have some important clinical implications including the possibility that the onset and/or worsening of tinnitus can antedate the destabilization of chronic heart failure. This would allow for the early identification of patients who deserve a more aggressive management of heart failure or an adjustment of drug treatment, including a cautious administration of NSAIDs. If confirmed by larger prospective studies, this evidence would indirectly contribute to improve the quality of life of patients with chronic heart failure and might reduce the rate of hospitalization, as well as the huge economic burden of the management of chronic heart failure.

From: World J Biol Psychiatry. 2011 May 13. [Epub ahead of print]

Depressive symptoms are common in individuals with tinnitus and may substantially aggravate their distress. The mechanisms, however, by which depression and tinnitus mutually interact are still not fully understood.

Here the authors review neurobiological knowledge relevant for the interplay between depression and tinnitus. Neuroimaging studies confirm the existence of neural circuits that are activated both in depression and tinnitus. Studies of neuroendocrine function demonstrate alterations of the HPA-axis in depression and, more recently, in tinnitus.

Studies addressing neurotransmission suggest that the dorsal cochlear nucleus that is typically hyperactive in tinnitus, is also involved in the control of attention and emotional responses via projections to the locus coeruleus, the reticular formation and the raphe nuclei. Impaired hippocampal neurogenesis has been documented in animals with tinnitus after noise trauma, as in animal models of depression.

Finally, from investigations of human candidate genes, there is some evidence to suggest that variant BDNF may act as a common susceptibility factor in both disorders.

These parallels in the pathophysiology of tinnitus and depression argue against comorbidity by chance and against depression as pure reaction on tinnitus. Instead, they stand for a complex interplay between tinnitus and depression. Implications for tinnitus treatment are discussed

From: Mil Med. 2011 Apr;176(4):461-7.

The association between military service and symptoms of hearing loss including tinnitus is well known, with a number of countries strengthening hearing conservation programs for their serving defense personnel. In many cases of occupation related hearing loss, the problem is attributed to noise exposure alone. Although noise is the most common preventable cause of irreversable sensorineural hearing loss in the general population, focusing solely on noise ignores a number of other potential causes of ototoxicity. A number of chemical compounds are known or suspected to have the ability induce ototoxic effects, including solvents, heavy metals, pesticides and asphyxiants such as carbon monoxide.

Although many occupational studies indicate a possible likely relationship between chemical exposures and hearing impairment, the exact nature of any effects in humans has proved difficult to establish. In particular, the impact of nonwork factors such as the ageing process and noisy recreation activities is difficult to assess. Tobacco smoking is a further confounding factor as cigarette smoke contains a number of known or suspected ototoxic chemicals, including hydrogen cyanide, carbon monoxide, cadmium and lead. A substantial body of research demonstrates that smoking behaviors impact negatively on hearing, particularly at high frequencies, although there is no clear relationship between tinnitus and smoking.

Of considerable concern are the effects noted in the literature arising from simulteneous exposure to one or more ototoxic factors. When exposure to noise is accompanied by exposure to one or more ototoxic substances, the impact on hearing has been demonstrated in several studies to be greater than that predicted by the sum of individual effects.

The objective of this study was to investigate the effect of chemical and environmental exposures during deployment on tinnitus among Australian Defence Force personnel previously deployed to Bougainville and East Timor. Participants were asked to self-report recent occurrence and severity of “ringing in the ears,” and identify any chemical and environmental exposures during their deployment. Self-reported exposure to loud noises, heavy metals, intense smoke, engine exhaust, solvents and degreasing agents, and chemical spills increased the risk of self-assessed moderate or severe tinnitus.

Daily exposure to 4 or more ototoxic factors was associated with 2- to 4-fold increase in the risk. In addition to loud noises, chemical exposures may also play a role in the development of tinnitus among Australian Defence Force personnel serving overseas.

From: J Am Acad Audiol. 2000 Mar;11(3):115-24

The symptoms and signs of severe tinnitus and chronic pain have many similarities and similar hypotheses have been presented regarding how the symptoms are generated. Pain and tinnitus have many different forms. The severity of the symptoms of both varies within wide limits, and it is not likely that all forms have the same pathology. Some individuals with severe tinnitus perceive sounds to be unpleasant or painful. This may be similar to what is known as allodynia, which is a painful sensation of normally innocuous stimulation of the skin. Many individuals with chronic pain experience a worsening of their pain from repeated stimulation (the “wind-up” phenomenon). This is similar to the increasingly unpleasant feeling from sounds that are repeated that many individuals with severe tinnitus experience. There are also similarities in the hypotheses about the generation of pain and tinnitus. Although less severe tinnitus may be generated in the ear, it is believed that severe tinnitus in many cases is caused by changes in the nervous system that occur as a result of neural plasticity. Acute pain caused by tissue injury is generated at the site of injury but chronic pain is often generated in the central nervous system, yet another similarity between chronic pain and severe tinnitus. The changes in the nervous system consist of altered synaptic efficacy including opening of dormant synapses. For pain, this is believed to occur in the wide dynamic range neurons of the spinal cord and brain stem. Less is known about the anatomic location of the changes that cause severe tinnitus but there are indications that it may be the inferior colliculus. It is also possible that other auditory systems than the classical ascending pathways may be involved in severe tinnitus.

In, Similarities between chronic pain and tinnitus, Am J Otol. 1997 Sep;18(5):577-85.

The authors review hypotheses about the mechanisms of chronic pain and to compare them with that of tinnitus. Hypotheses about the pathophysiology of severe tinnitus and chronic pain have been of mainly two kinds: one of which claims that pathology located in the periphery (the ear for tinnitus, and peripheral nerves for pain) can explain the symptoms, while the other claims that the symptoms are caused by changes in the function of nuclei of the central nervous system.

A search of the literature from the past 35 years was used leading to conclude that there is considerable evidence that both chronic pain and some forms of tinnitus are caused by changes in the central nervous system and that the anatomic location of the physiologic abnormality causing the symptoms of chronic pain and some forms of tinnitus is not the same location to which the symptoms are referred, i.e., the ear for tinnitus and the location of injury for pain. Such changes in the central nervous system may have been induced by peripheral processes such as tissue damage, but the changes can persist a long time after complete healing of a peripheral lesion. Different forms of tinnitus may respond to different treatments as is the case for chronic pain. If the different forms of tinnitus cannot be separated, then the results of studies of the efficacy of different kinds of drugs may be misleading.

In, Tinnitus and pain. Prog Brain Res. 2007;166:47-53, It was noted, tnnitus has many similarities with the symptoms of neurological disorders such as paresthesia and central neuropathic pain. There is considerable evidence that the symptoms and signs of some forms of tinnitus and central neuropathic pain are caused by functional changes in specific parts of the central nervous system and that these changes are caused by expression of neural plasticity. The changes in the auditory nervous system that cause tinnitus and the changes in the somatosensory systems that cause central neuropathic pain may have been initiated from the periphery, i.e. the ear or the auditory nerve for tinnitus and receptors and peripheral nerves in the body for pain. In the chronic condition of tinnitus and pain, abnormalities in the periphery may no longer play a role in the pathology, but the tinnitus is still referred to the ear and central neuropathic pain is still referred to the location on the body of the original pathology. In this chapter the authors discuss specific similarities between tinnitus and pain, and compare tinnitus with other phantom disorders. Since much more is known about pain than about tinnitus, it is valuable to take advantage of the knowledge about pain in efforts to understand the pathophysiology of tinnitus and find treatments for tinnitus.

In The role of neural plasticity in tinnitus. Prog Brain Res. 2007;166:37-45, There is considerable evidence that expression of neural plasticity plays a central role in the development of the abnormalities that cause many forms of tinnitus. Expression of neural plasticity can change the balance between excitation and inhibition, promote hyperactivity, and cause re-organization of specific parts of the nervous system or redirection of information to parts of the nervous system not normally involved in processing of sounds (such as the non-classical, or extralemniscal pathways). The strongest promoter of expression of neural plasticity is deprivation of input, which explains why tinnitus often occurs together with hearing loss or injury to the auditory nerve.

Related Source: Prevalence and Characteristics of Tinnitus Aamong US Adults

From: Int J Audiol. 2011 Feb 10. [Epub ahead of print]

To assess the prevalence of tinnitus along with factors potentially associated with having tinnitus. Data were from the Beaver Dam Offspring Study, an epidemiological cohort study of aging. After a personal interview and audiometric examination, 3267 participants were classified as having tinnitus if in the past year they reported having tinnitus of at least moderate severity or that caused difficulty in falling asleep.

The prevalence of tinnitus was 10.6%. In a multivariable logistic regression model adjusting for age and sex, the following factors were associated with having tinnitus: hearing impairment, currently having a loud job, history of head injury, depressive symptoms, history of ear infection, history of target shooting, arthritis, and use of NSAID medications. For women, ever drinking alcohol in the past year was associated with a decreased risk of having tinnitus.

These results suggest that tinnitus is a common symptom in this cohort and may be associated with some modifiable risk factors.

From: Int J Environ Res Public Health. 2010 Aug;7(8):3071-9. Epub 2010 Aug 4.

Tinnitus is a perception of sound without an external source. This perception can be induced by various dysfunctions on several levels of the peripheral or central auditory pathway. Regardless of the original cause, all patients complain of hearing a tinnitus tone on either one (unilateral) or both sides (bilateral) of the head or ears. Depending on the case, tinnitus tone may have low, medium or high frequency and be either relatively quiet (0–3 dB), going up to relatively loud (more than 16 dB). Tinnitus may take acute (up to 3 months), sub-acute (4–12 months) or a chronic turn (longer than a year). Regarding the level of disturbance, tinnitus can be classified as compensated (low-level distress) or decompensated (high-level distress). The major problem in patients with decompensated tinnitus is sleep interference, because the tinnitus tone keeps the patients awake. Other diseases that follow include depression, a variety of phobias, anxiety disorders, problems with concentration and in extreme cases—suicide. In other words, decompensated tinnitus seriously reduces the quality of life. Approximately 30 per 100 adults experience tinnitus, whereas about 1–5 persons per 100 suffer from tinnitus and seek medical help. In the Western world, tinnitus has a big economic impact.

The onset of tinnitus can have various basis such as neurologic, traumatic, infectious or drug-related, however, the major cause of tinnitus is a hearing loss. Hearing loss is usually caused by the aging process (presbycusis) or by the overexposure to noise (noise-induced hearing loss). Occupational noise, together with environmental noise pollution, are two major factors contributing to the noise-induced hearing loss. Newly emerging noise-induced hearing loss victims are adolescents who inappropriately use MP3 or MP3-like personal players (too long/too loud, using earphone-insert type headphones). Between 57% and 76% of tinnitus patients were shown to have noise-induced hearing loss. These, and a lot of other data, strongly indicate coexistence of both hearing dysfunctions. Based on the above data the authors put forward a hypothesis that the degree of hearing loss could negatively influence the severity of tinnitus. To test the hypothesis we used a retrospective study using data acquired from 531 tinnitus patients. This data were randomly collected on the admission of patients who reported to the day ward of Tinnitus Center at the Charité – Universitätsmedizin in Berlin between January 2008 and March 2010. The authors have analyzed general audiometric and tinnitus-oriented psychometric parameters.

The present work was aimed at analyzing the association between noise, the grade of the noise-induced hearing loss and the severity of tinnitus. The results partially corroborate the findings of others by demonstrating a strong bond between the noise-induced hearing loss and tinnitus. In fact, the authors have shown that 83% of patients with chronic and sub-acute forms of tinnitus have a high-frequency hearing loss, which is a substantially higher percentage than the 57% to 63% previously reported. The sample size in all studies was roughly similar, as were the age and gender distribution. However, there was a major difference in the duration of tinnitus between our and the other studies. In a previous study, 49% of tinnitus patients had suffered from tinnitus for a time shorter than one year – a group classified as acute and sub-acute tinnitus. In another previous study, there were 38% of patients with acute (duration of less than three months) and 36% of patients with sub-acute tinnitus (between four and twelve months). Of the authors patients, none suffered from acute tinnitus. Based on the above evidence, one is tempted to cautiously speculate that the tinnitus associated with hearing loss has a greater chance of chronification than the tinnitus without hearing loss. Obviously, more studies are needed to validate this observation. In the other study, subgroups of patients with tinnitus were indentified who were actively looking for a remedy. This group was called “Tinnitus Seeking Help Group”. Intriguingly, 100% of the “Tinnitus Seeking Help Group” suffered from the noise-induced hearing loss. This observation supports the authors records and suggests similarities between the noise-induced hearing loss, “Tinnitus Seeking Help Group” and patients in this study, who also were actively looking for help.

The authors found a significant correlation between the mean hearing loss and the tinnitus loudness. The fact that the loudness of tinnitus is increased in patients with coexisting hearing loss has been already known, but the observation of the dependency of tinnitus loudness on the severity of the hearing loss is a new one. Our study gives a base for the explanation of how the degree of noise-induced hearing loss indirectly affects the severity of tinnitus by influencing negatively the loudness of tinnitus. In agreement with this, the degree of hearing loss correlated positively with two subscales (“intrusiveness” and “auditory perceptional difficulties”) of the Tinnitus Questionnaire. These particular items of the questionnaire regard the ability to communicate, which is an integral part of the quality of life. There is a known negative association between tinnitus distress and the quality of life. The most affected areas of life are social activities like communication and social life. With the increased distress of tinnitus, patients withdraw from their normal social life and avoid contacts with others, consistent with the decompensated form of tinnitus. Interestingly, the authors found that the patients suffering with decompensated tinnitus had a greater degree of hearing loss than the patients with compensated tinnitus.

Noise pollution and occupational noise were demonstrated to induce asymmetric hearing loss, with the left side being affected more than the right one. Although the analyses demonstrated no statistically significant differences in the hearing loss between the left and the right sides, the authors found that left sided tinnitus is more distressing than the right sided one. Moreover, patients with the left sided tinnitus had more complaints in the somatic subscale than the right sided tinnitus patients. This could be attributed to neuroanatomic differences between the left and right parts of the auditory system.

Noise, either occupational or environmental noise pollution, is a major preventable cause of the hearing loss and therefore of chronic tinnitus. The consequences of noise exposure last for life, as the sensory auditory epithelium never regenerates. The price to pay for the noise exposure includes not only a limited ability to hear but also increased chance to develop chronic decompensated tinnitus, which separates the affected persons from normal social activities and significantly decreases the quality of life.

This study demonstrates that the chain of events started by overexposure to noise not only induces the hearing loss but also tinnitus with its co-morbidities, finally resulting in a decreased quality of life.

From: Am J Med. 2010 Aug;123(8):711-8

Tinnitus, derived from the Latin word tinnire meaning “to ring,” is the perception of noise in the absence of an acoustic stimulus. It is a common condition that is usually subjective, perceived only by the patient, and therefore diagnosis and monitoring rely on self-report. Data from the 1996 National Health Interview Survey (NHIS) showed tinnitus was experienced by approximately 35-50 million adults in the US, with 12 million seeking medical care, and 2-3 million reporting symptoms that were severely debilitating. Cases and proposed etiologies of tinnitus are clinically heterogeneous and, although several treatment options have been tried, no single cure exists for the condition.

Patients who experience tinnitus often report significant associated morbidities. Lifestyle detriment, emotional difficulties, sleep deprivation, work hindrance, interference with social interaction, and decreased overall health have been attributed to tinnitus. Although causative relations are yet unknown, patients with tinnitus can have increased risk for depression, anxiety, and insomnia.

A limited number of risk factors for tinnitus have been suggested, the best described of which include increasing age, hearing loss, and loud noise exposure. These associations merit further exploration in a large cohort. Furthermore, the relations between tinnitus and other demographic and health factors are minimally characterized in the current literature. Therefore, the authors examined the relation between tinnitus and several potential risk factors using data from the National Health and Nutrition Examination Survey (NHANES), a large nationally representative survey.

The overall prevalence of tinnitus in the US was 25.3%, corresponding to a national estimate of 50 million adults. This prevalence is consistent with the upper range of the overall estimate previously reported from the NHIS (35-50 million). Similar to data from the Beaver Dam cohort, the prevalence of tinnitus in our study increased with age until the age of 60-69 years, after which it decreased with increasing age. This inverse relationship between age and tinnitus in older age groups has been demonstrated in several previous studies. One possible mechanism for this observation is that tinnitus may be associated with other conditions that confer a selective mortality disadvantage among individuals with tinnitus. The possibility also exists, however, that late symptomatic improvement may be part of the natural history of tinnitus.

The results of this study showed that non-Hispanic blacks and Hispanics had lower prevalence of any and frequent tinnitus than non-Hispanic whites. Although decreased prevalence in hearing loss has been reported previously in non-Hispanic blacks and Hispanics compared with non-Hispanic whites, this study is the first to report this association between race/ethnicity and tinnitus. The fact that significant associations between race/ethnicity and tinnitus were maintained in participants without hearing impairment suggests a mechanism for tinnitus that is independent of hearing impairment.

The significant associations between tinnitus and smoking and hypertension in this study suggest that vascular disease might have a greater contribution to the etiology of tinnitus than previously reported. Associations between cigarette smoking and hearing loss have previously been suggested, but data on the association between smoking and tinnitus remains scant. The data from the authors showed that current and past smoking confer increased odds of experiencing tinnitus. Although multiple past studies have analyzed the relation between cardiovascular disease and tinnitus, information on the association between hypertension and tinnitus has, up to now, been limited to cases of pulsatile tinnitus from vascular etiologies. These cases likely represent a minority of patients with tinnitus, as most patients with tinnitus present with subjective, sensorineural tinnitus.

Loud noise exposure is generally considered an important risk factor for developing tinnitus. In this study, history of leisure-time, occupational, and firearm noise exposure were all associated with increased odds of tinnitus. The relation between noise exposure and frequent tinnitus, however, differed depending on the presence or absence of hearing impairment. Occupational noise exposure was associated with increased odds of frequent tinnitus in participants with hearing impairment, while leisure-time noise exposure was associated with increased odds of frequent tinnitus in participants without hearing impairment. Occupational noise exposure has been reported to be strongly associated with both tinnitus and hearing loss, possibly due to its chronic effects on inner hair cell, outer hair cell, and acoustic nerve function. However, after an acute acoustic trauma, tinnitus is reported in the initial stages in 90% of the cases, and often persists even when the hearing loss is temporary. The differential vulnerability of cochlear and central components to duration and intensity of noise exposure may explain the variability between tinnitus and hearing loss in noise-exposed subjects.

These results demonstrate an important relation between tinnitus and mental health, as both anxiety and major depressive disorder were associated with increased odds of tinnitus. Participants with a history of either major depressive disorder or generalized anxiety disorder had greater than twice the odds of reporting any tinnitus compared with those not affected by these disorders. In addition, participants with a history of generalized anxiety disorder had >6 times the odds of reporting tinnitus compared with unaffected participants. Although this study is the first nationally representative study to find an association between tinnitus and mental health disorders, numerous smaller studies have reported similar associations. The cause for these associations is not yet known. Tinnitus can result in sleep deprivation, decreased work productivity, and overall lifestyle detriment. These factors might cause psychological distress and bring about or worsen symptoms of anxiety and depression. Major depressive disorder and generalized anxiety disorder, on the other hand, may exacerbate tinnitus, and their treatment might alleviate tinnitus.

Several strengths and limitations of this study should be considered. Data from NHANES is comprehensive and nationally representative, drawing from a large and diverse sample of participants. The study is, however, cross-sectional, making causative relationships impossible to determine. Tinnitus is most often a subjective complaint without a means of objective diagnosis. Therefore, comparisons between participants and studies are difficult. But, during the period of this study, consistency was maintained in assessing the presence and quality of tinnitus among participants.

In conclusion, these results offer insight into the prevalence of tinnitus and identify potentially vulnerable groups. We have demonstrated that, although the prevalence of tinnitus is generally higher at older ages, it also is frequently reported in young adults. Likewise, the potential risk factors for developing tinnitus are significant even in the younger adults. Therefore, opportunities may exist to prevent tinnitus, starting at a younger age. As no known cure exists for tinnitus, it is important to investigate potentially modifiable risk factors for tinnitus. Future research should examine the prospective relations between smoking, hypertension, noise exposure, and mental health conditions and tinnitus.

Clinical Significance:
•Tinnitus is a very common and potentially disabling condition, but few risk factors for its development are currently known.
•The relations between tinnitus and other demographic and health factors are minimally characterized in the current literature.
•Because tinnitus currently has no known cure, identifying potentially vulnerable groups and establishing potential risk factors in a large, nationally representative study is important for decreasing the burden of this condition.

From: Eur Arch Otorhinolaryngol. 2010 Jun 25. [Epub ahead of print]

The aim of this work is to study the characteristics of tinnitus both in normal hearing subjects and in patients with hearing loss. The study considered tinnitus sufferers, ranging from 21 to 83 years of age, who were referred to the Audiology Section of Palermo University in the years 2006-2008. The following parameters were considered: age, sex, hearing threshold, tinnitus laterality, tinnitus duration, tinnitus measurements and subjective disturbance caused by tinnitus. The sample was divided into Group1 (G1), 115 subjects with normal hearing, and Group2 (G2), 197 subjects with hearing loss. Especially for G2, there was a predominance of males compared to females; the highest percentage of tinnitus resulted in the decades 61-70 and >70 with a significant difference for G2 demonstrating that the hearing status and the elderly represent the principal tinnitus-related factors.

The hearing impairment resulted in most cases of sensorineural hearing loss type and was limited to the high frequencies; the 72.1% of the patients with sensorineural hearing loss had a high-pitched tinnitus, while the 88.4% of the patients with a high-frequency sensorineural hearing loss had a high-pitched tinnitus. As to the subjective discomfort, the catastrophic category was the most representative among G1 with a significant difference between the two groups; no correlation was found between the level of tinnitus intensity and the tinnitus annoyance confirming the possibility that tinnitus discomfort is elicited by a certain degree of psychological distress as anxiety, depression, irritability and phobias.

In Auris Nasus Larynx. 2010 Apr 27. Characteristics of tinnitus with or without hearing loss: Clinical observations in Sicilian tinnitus patients. It was concluded that the hearing status and the elderly represent the principal tinnitus related factors; moreover tinnitus characteristics differ in the two groups for tinnitus pitch. There is, in fact, a statistically significant association between high-pitched tinnitus and high-frequency sensorineural hearing loss suggesting that the auditory pathway reorganization induced by hearing loss could be one of the main source of the tinnitus sensation.

In Eur Arch Otorhinolaryngol. 2008 Nov;265(11):1295-300. Tinnitus with or without hearing loss: are its characteristics different? This study confirmed that tinnitus is most frequently associated with hearing loss. The characteristics of tinnitus in normal hearing subjects, except for the subjective judgment of tinnitus intensity, the pitch and the inhibition, are significantly different for those observed in subjects with hearing loss. The association of tinnitus and hearing deficit seems to increase the perceived severity of the symptom.