Tinnitus


Tinnitus is a condition when a person hears a ringing sound or a different variety of sounds when no corresponding external sound is present and that other people cannot hear. The word tinnitus comes from the Latin tinnire, "to ring".
Tinnitus is usually associated with hearing loss and decreased comprehension of speech in noisy environments. It is common, affecting about 10–15% of people. Most tolerate it well, and it is a significant problem in only 1–2% of people.
Rather than a disease, tinnitus is a symptom that may result from a variety of underlying causes and may be generated at any level of the auditory system as well as outside that system. The most common causes are hearing damage, noise-induced hearing loss, or age-related hearing loss, known as presbycusis. Other causes include ear infections, disease of the heart or blood vessels, Ménière's disease, brain tumors, acoustic neuromas, migraines, temporomandibular joint disorders, exposure to certain medications, a previous head injury, and earwax. In some people, it interferes with concentration, and can be associated with anxiety and depression. It can suddenly emerge or increase during a period of emotional stress. It may have a frequent occurrence in those with depression.
The diagnosis of tinnitus is usually based on a patient's description of the symptoms they are experiencing. Such a diagnosis is commonly supported by an audiogram, and an otolaryngological and neurological examination. How much tinnitus interferes with a person's life may be quantified with questionnaires. If certain problems are found, medical imaging, such as magnetic resonance imaging, may be performed. Other tests are suitable when tinnitus occurs with the same rhythm as the heartbeat. Rarely, the sound may be heard by someone other than the patient by using a stethoscope, in which case it is known as "objective tinnitus". Occasionally, spontaneous otoacoustic emissions, sounds produced normally by the inner ear, may result in tinnitus.
Measures to prevent tinnitus include avoiding chronic or extended exposure to loud noise, and limiting exposure to drugs and substances harmful to the ear. If there is an underlying cause, treating that cause may lead to improvements. Otherwise, typically, tinnitus management involves psychoeducation or counseling, such as talk therapy. Sound generators or hearing aids may help. No medication directly targets tinnitus.

Signs and symptoms

Tinnitus is often described as ringing, but it may also sound like clicking, buzzing, hissing, or roaring. It may be soft or loud, low- or high-pitched, and may seem to come from either one or both ears, or from other parts of the head. It may be intermittent or continuous. In some individuals, its intensity may be changed by shoulder, neck, head, tongue, jaw, or eye movements.

Course

Due to variations in study designs, data on the course of tinnitus shows few consistent results. Generally, prevalence increases with age in adults, and the ratings of annoyance increase with persistence at follow up.

Adverse psychological effects

Although it is an annoying condition to which most people adapt, persistent tinnitus may cause anxiety and depression in some people. Tinnitus annoyance is more strongly associated with the psychological condition of the person than the loudness or frequency range of the perceived sound. Psychological problems such as depression, anxiety, sleep disturbances, and concentration difficulties are common in those with strongly annoying tinnitus. One study found that complications can also include cognitive decline and difficulty communicating, and 45% of people with tinnitus in that study had an anxiety disorder at some time in their lives. Severe cases may lead some to consider suicide; while suicidal behavior is complex, tinnitus can be a risk factor. In a cross-sectional analysis, 15.75% of the 292 patients that attended a 2019 Tinnitus and Hyperacusis Clinic in the United Kingdom "expressed that they have been bothered by suicidal and self-harm ideations within the last 2 weeks."
Psychological research has focused on the tinnitus distress reaction to account for differences in tinnitus severity. The research indicates that among the cohort studied, conditioning at the initial perception of tinnitus linked it with negative emotions, such as fear and anxiety.

Types

Commonly tinnitus is classified into "subjective and objective tinnitus". Tinnitus is usually subjective, meaning that the sounds the person hears are not detectable by means currently available to physicians and hearing technicians. Subjective tinnitus has also been called "tinnitus aurium", "non-auditory", or "non-vibratory" tinnitus.
In rare cases, tinnitus may be heard by someone else using a stethoscope. Even more rarely, in some cases it may be measured as a spontaneous otoacoustic emission in the ear canal. This is classified as "objective tinnitus", also called "pseudo-tinnitus" or "vibratory" tinnitus.

Subjective tinnitus

Subjective tinnitus is the most frequent type. It may have many causes, but most commonly it results from hearing loss. When it is caused by disorders of the inner ear or auditory nerve, it can be called "otic". These otological or neurological disorders include those triggered by infections, drugs, or trauma. A cause is traumatic noise exposure that damages the sensory cilia, or hair cells, in the inner ear. Some evidence suggests that long-term exposure to noise pollution from heavy traffic may increase the risk of developing tinnitus.
When there does not seem to be a connection with a disorder of the inner ear or auditory nerve, tinnitus may be called "non-otic". In 30% of cases, tinnitus is influenced by the somatosensory system; for instance, people can increase or decrease their tinnitus by moving their face, head, jaw, or neck. This type is called somatic or craniocervical tinnitus, since it is only head or neck movements that have the effect.
Some tinnitus may be caused by neuroplastic changes in the central auditory pathway. In this theory, the disturbance of sensory input caused by hearing loss results in such changes, as a homeostatic response of neurons in the central auditory system, causing tinnitus.
When some frequencies of sound are lost to hearing loss, the auditory system compensates by amplifying those frequencies, eventually producing sound sensations at those frequencies constantly, even when there is no corresponding external sound.

Hearing loss

The most common cause of tinnitus is hearing loss. Hearing loss may have many different causes, but among those with tinnitus, the major cause is cochlear injury.
In many cases, no underlying cause is identified.
Ototoxic drugs also may cause subjective tinnitus, as they may cause hearing loss, or increase the damage done by exposure to loud noise. This damage may occur even at doses not considered ototoxic. More than 260 medications have been reported to cause tinnitus as a side effect.
Tinnitus may also occur from the discontinuation of therapeutic doses of benzodiazepines. It may sometimes be a protracted symptom of benzodiazepine withdrawal and may persist for many months. Medications such as bupropion may also cause tinnitus.

Associated factors

Factors associated with tinnitus include:
A specific type of tinnitus, objective tinnitus, is characterized by hearing the sounds of one's own muscle contractions or pulse, typically a result of sounds that have been created by the movement of jaw muscles or sounds related to blood flow in the neck or face. This type of tinnitus is sometimes caused by an involuntary twitching of a muscle or a group of muscles or by a vascular condition. In some cases, tinnitus is generated by muscle spasms around the middle ear.
Spontaneous otoacoustic emissions —faint high-frequency tones that are produced in the inner ear and may be measured in the ear canal with a sensitive microphone—may also cause tinnitus. About 8% of those with SOAEs and tinnitus have SOAE-linked tinnitus, while the percentage of all cases of tinnitus caused by SOAEs is estimated at 4%.

Pediatric tinnitus

Children may be subject to pulsatile or continuous tinnitus, involving anomalies and variants of the vascular parts affecting the middle/inner ear structures. CT scans may be used to check the integrity of the structures, and MR scans may evaluate nerves and potential masses or malformations. Early diagnosis may prevent long-term impairments to development.

Pulsatile tinnitus

Some people experience a sound that beats in time with their pulse, known as pulsatile tinnitus or vascular tinnitus. Pulsatile tinnitus is usually objective in nature, resulting from altered blood flow or increased blood turbulence near the ear, such as from atherosclerosis or venous hum, but it may also arise as a subjective phenomenon from an increased awareness of blood flow in the ear.
The differential diagnosis for pulsatile tinnitus is wide and includes vascular etiologies, tumors, disorders of the middle ear or inner ear, and other intracranial pathologies. Vascular causes of pulsatile tinnitus include venous causes, arterial causes, or dural arteriovenous fistula or arteriovenous malformations.
Pulsatile tinnitus may also indicate vasculitis, or more specifically, giant cell arteritis. Pulsatile tinnitus may also be caused by tumors such as paragangliomas, or hemangiomas. Middle ear causes of pulsatile tinnitus include patulous eustachian tube, otosclerosis, or middle ear myoclonus. The most common inner ear cause of pulsatile tinnitus is superior semicircular canal dehiscence. Pulsatile tinnitus may also indicate idiopathic intracranial hypertension. Pulsatile tinnitus may be a symptom of intracranial vascular abnormalities and should be evaluated for irregular noises of blood flow.