tinnitus tinnitus tinnitus is a variety of sound that is heard when no corresponding external sound is present. nearly everyone experiences faint "normal tinnitus" in a completely quiet room; but it is of concern only if it is bothersome, interferes with normal hearing, or is associated with other problems. the word tinnitus comes from the latin tinnire, "to ring". in some people, it interferes with concentration, and can be associated with anxiety and depression. tinnituspronunciation/ˈtɪnɪtəs/ or /tɪˈnaɪtəs/ specialtyotorhinolaryngology, audiologysymptomshearing sound when no external sound is presentcomplicationspoor concentration, anxiety, depressionusual onsetgradualcausesnoise-induced hearing loss, ear infections, disease of the heart or blood vessels, ménière's disease, brain tumors, inner ear tumors, emotional stress, traumatic brain injury, excessive earwaxdiagnostic methodbased on symptoms, audiogram, neurological examtreatmentcounseling, sound generators, hearing aidsfrequency~12.5% 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. it can trigger a fight-or-flight response, as the brain may perceive it as dangerous and important. 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 (tumors on the auditory nerves of the ear), migraines, temporomandibular joint disorders, exposure to certain medications, a previous head injury, and earwax. it can suddenly emerge during a period of emotional stress. it is more common 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 (mri), 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 ototoxic drugs and substances. 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 the head itself. 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 decreases with duration. 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. 45% of people with tinnitus have an anxiety disorder at some time in their lives. psychological research has focused on the tinnitus distress reaction to account for differences in tinnitus severity. the research indicates that 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 can be heard by someone else using a stethoscope. even more rarely, in some cases it can be measured as a spontaneous otoacoustic emission (soae) 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 can 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" (from the greek word for ear). these otological or neurological disorders include those triggered by infections, drugs, or trauma. a frequent cause is traumatic noise exposure that damages 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 can 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, or neck. this type is called somatic or craniocervical tinnitus, since it is only head or neck movements that have an 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 can also occur from the discontinuation of therapeutic doses of benzodiazepines. it can 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: ear problems and hearing loss: conductive hearing loss acoustic shock loud noise or music middle ear effusion otitis otosclerosis eustachian tube dysfunction sensorineural hearing loss excessive or loud noise; e.g. acoustic trauma presbycusis (age-associated hearing loss) ménière's disease endolymphatic hydrops superior canal dehiscence acoustic neuroma mercury or lead poisoning ototoxic medications neurologic disorders: arnold–chiari malformation multiple sclerosis head injury giant cell arteritis temporomandibular joint dysfunction metabolic disorders: vitamin b12 deficiency iron deficiency anemia psychiatric disorders depression anxiety disorders other factors: vasculitis some psychedelic drugs can produce temporary tinnitus-like symptoms as a side effect: 5-meo-det diisopropyltryptamine (dipt) benzodiazepine withdrawal intracranial hyper or hypotension caused by, for example, encephalitis or a cerebrospinal fluid leak objective tinnitus 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. it is sometimes caused by an involuntary twitching of a muscle or a group of muscles (myoclonus) or by a vascular condition. in some cases, tinnitus is generated by muscle spasms around the middle ear. spontaneous otoacoustic emissions (soaes)—faint high-frequency tones that are produced in the inner ear and can 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 can evaluate nerves and potential masses or malformations. early diagnosis can 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 can also arise as a subjective phenomenon from an increased awareness of blood flow in the ear. rarely, pulsatile tinnitus may be a symptom of potentially life-threatening conditions such as carotid artery aneurysm or carotid artery dissection. pulsatile tinnitus may also indicate vasculitis, or more specifically, giant cell arteritis. pulsatile tinnitus may also indicate idiopathic intracranial hypertension. pulsatile tinnitus can be a symptom of intracranial vascular abnormalities and should be evaluated for irregular noises of blood flow (bruits). pathophysiology tinnitus may be caused by increased neural activity in the auditory brainstem, where the brain processes sounds, causing some auditory nerve cells to become overexcited. the basis of this theory is that many with tinnitus also have hearing loss. three reviews in 2016 emphasized the large range and possible combinations of pathologies involved in tinnitus, which result in a great variety of symptoms and specifically adapted therapies. diagnosis the diagnostic approach is based on a history of the condition and an examination of the head, neck, and neurological system. typically an audiogram is done, and occasionally medical imaging or electronystagmography. treatable conditions may include middle ear infection, acoustic neuroma, concussion, and otosclerosis. evaluation of tinnitus can include a hearing test (audiogram), measurement of acoustic parameters of the tinnitus like pitch and loudness, and psychological assessment of comorbid conditions like depression, anxiety, and stress that are associated with severity of the tinnitus. one definition of tinnitus, in contrast to normal ear noise experience, is that tinnitus lasts five minutes at least twice a week. however, people with tinnitus often experience the noise more frequently than this. tinnitus can be present constantly or intermittently. some people with constant tinnitus might not be aware of it all the time, but only, for example, during the night when there is less environmental noise to mask it. chronic tinnitus can be defined as tinnitus with a duration of six months or more. audiology since most people with tinnitus also have hearing loss, a pure tone hearing test resulting in an audiogram may help diagnose a cause. an audiogram may also facilitate fitting of a hearing aid in those cases where hearing loss is significant. the pitch of tinnitus is often in the range of the hearing loss. psychoacoustics acoustic qualification of tinnitus includes measurement of several acoustic parameters like frequency in cases of monotone tinnitus or frequency range and bandwidth in cases of narrow band noise tinnitus, loudness in db above hearing threshold at the indicated frequency, mixing-point, and minimum masking level. in most cases, tinnitus pitch or frequency range is between 5 khz and 10 khz, and loudness between 5 and 15 db above the hearing threshold. another relevant parameter of tinnitus is residual inhibition: the temporary suppression or disappearance of tinnitus following a period of masking. the degree of residual inhibition may indicate how effective tinnitus maskers would be as treatment. an assessment of hyperacusis, a frequent accompaniment of tinnitus, may also be made. hyperacusis is related to negative reactions to sound and can take many forms. one parameter that can be measured is loudness discomfort level (ldl) in db, the subjective level of acute discomfort at specified frequencies over the frequency range of hearing. this defines a dynamic range between the hearing threshold at that frequency and the loudness discomfort level. a compressed dynamic range over a particular frequency range can be associated