34 TInnitus Flashcards
What is tinnitus?
What is tinnitus?
Tinnitus is an involuntary perception of sound that originates in the head and is not attributable to a perceivable external source. The word tinnitus is derived from the Latin tinnire, which means to ring. Tinnitus is often described as a “ringing” sound in the ear, but also includes descriptions such as buzzing, humming, roaring, hissing, and chirping. Tinnitus is a symptom and not a disease in itself.
What is the prevalence of tinnitus?
What is the prevalence of tinnitus?
It is generally accepted that about 10% to 15% of the population suffers from some degree of tinnitus, while 1% to 2% report that tinnitus has a severely negative impact on quality of life.
How can tinnitus be classified?
How can tinnitus be classified?
Tinnitus has historically been classified as either objective (audible to an observer other than the patient) or subjective (perceptible by the patient alone). More useful classification includes description of tinnitus as either pulsatile or nonpulsatile, or categorization by location of injury or generation (external ear, middle ear, sensorineural, or central).
What are somatosounds?
What are somatosounds?
A more specific term for many forms of objective tinnitus, somatosounds are objective sounds that are created by the body and potentially audible to the examiner. Examples of somatosounds include perception of myoclonic contractions of the tensor tympani or pulsatile variations in blood flow in vessels near the ear.
What are the proposed mechanisms to explain subjective tinnitus?
What are the proposed mechanisms to explain subjective tinnitus?
Both central and peripheral mechanisms have been proposed to explain the origin of tinnitus, but the exact cause remains unclear. Most tinnitus is associated with a cochlear abnormality, although not all patients with tinnitus have associated measurable changes in hearing. It has been proposed that sensory deprivation at the periphery leads to alterations in neural function at higher levels and persistence of these neural changes may contribute to the subjective perceptions of tinnitus. Tonotopic maps in the auditory cortex have been shown to reorganize in animal studies after sensory deprivation in a manner similar to somatosensory cortical organization changes after amputation, leading to the description of tinnitus as a “phantom limb” perception of the auditory cortex.
How is tinnitus evaluated?
How is tinnitus evaluated?
No objective test is available to definitively verify tinnitus or identify its cause in most cases. An evaluation of tinnitus consists of a thorough case history, complete otologic exam, and an audiometric evaluation. Evaluation may also consist of administration of one of several validated questionnaires, such as the Tinnitus Handicap Inventory, the Tinnitus Handicap Questionnaire, or the Tinnitus Severity Index. Though these surveys provide little objective data, they can help to quantify the severity of impact on quality of life and may be used to track changes in tinnitus perception across various therapy modalities. Additional studies, such as imaging or vestibular evaluation, may be indicated depending on the initial presentation and differential diagnosis.
What is tinnitus matching and what is its value in assessment and treatment of subjective tinnitus?
What is tinnitus matching and what is its value in assessment and treatment of subjective tinnitus?
Tinnitus matching is an audiometric evaluation that generally consists of pitch matching, loudness matching, and minimal suppression level (the amount of masking required to subjectively mask an individual’s tinnitus). These more objective measures of tinnitus have little validity or clinical application, as tinnitus loudness, pitch, and maskability typically bear no relationship to the severity of the patient’s experience or ability to benefit from treatment. Some treatment modalities, including individualized sound stimulation devices, may rely on pitch matching or minimum suppression levels to create customized listening programs targeted at masking an individual’s tinnitus.
What signs or symptoms are suggestive of a vascular cause of tinnitus?
What signs or symptoms are suggestive of a vascular cause of tinnitus?
A pulsatile or throbbing quality that parallels the heartbeat should raise the index of suspicion.
- A reddish or blue mass behind the tympanic membrane may indicate a glomus tumor arising within the middle ear or a dehiscence of the jugular bulb or carotid artery.
- Arteriovenous malformations are uncommon but may occur between the occipital artery (passing medial to the mastoid process) and the transverse sinus.
- Venous hum may represent one of the more common causes of vascular tinnitus. It may signify impingement of the jugular vein by the second cervical vertebrae or suggest an underlying high-output cardiac condition, such as anemia*, *exercise*, *pregnancy*, or *thyrotoxicosis.
What is the imaging study of choice for nonpulsatile tinnitus?
What is the imaging study of choice for nonpulsatile tinnitus?
MRI with gadolinium is the study of choice to exclude a vestibular schwannoma or other neoplasm of the cerebellopontine angle.
What is the imaging study of choice for pulsatile tinnitus?
What is the imaging study of choice for pulsatile tinnitus?
Pulsatile tinnitus suggests a vascular neoplasm, vascular anomaly, or vascular malformation (although the cause may be as simple as transient otitis media). Glomus tumors are the most common type of vascular neoplasm. Most neoplasms and anomalies are best seen on bone windows of CT studies. Dural vascular malformations are often elusive on all cross-sectional imaging studies, and conventional angiography may be necessary to make this diagnosis. Flow-sensitive MR images show vascular loops compressing the eighth cranial nerve. Carotid dissections, aneurysms, atherosclerosis, and fibromuscular dysplasia can be identified on both MR/MR-angiographic studies and CT/CT-angiographic studies.
Other causes such as otosclerosis and Paget’s disease may be seen on CT scan. Idiopathic intracranial hypertension often shows characteristic findings of empty sella, thinning of the bony skull base, and prominent arachnoid pits. Multiple sclerosis is a rare cause of pulsatile tinnitus and is best seen on MR studies.
What causes of tinnitus are associated with pathology of the external ear canal?
What causes of tinnitus are associated with pathology of the external ear canal?
Foreign bodies and cerumen accumulation often cause tinnitus. Hair, insects, and other small objects may come in contact with the tympanic membrane and motion may cause the perception of sound. The mandibular condyle is in close proximity with the external ear canal and disorder of the temporomandibular joint may result in a somatosound perception. Thorough case history and a careful examination are important to help rule out these causes, which often may be easily treated.
What is palatal myoclonus?
What is palatal myoclonus?
Palatal myoclonus is the regular, rhythmic contraction of the soft palate and pharyngeal musculature. The muscles involved are the tensor veli palatine, levator veli palatine, salpingopharyngeus, and superficial pharyngeal constrictor.
How can palatal myoclonus be evaluated?
How can palatal myoclonus be evaluated?
The best way to detect palatal myoclonus is by using flexible nasopharyngoscopy in the awake patient to visualize the palate from a superior perch in the nasopharynx. Examining the palate from an oral cavity approach may lead to temporary extermination of the myoclonus while the mouth is stretched open. From a practical approach, both methods of examination should be used.
What is stapedial myoclonus?
What is stapedial myoclonus?
The rhythmic contractions of the stapedius muscle of the middle ear are known to cause a clicking tinnitus. The tensor tympani may also demonstrate a similar middle ear myoclonus.
How can stapedial myoclonus be evaluated?
How can stapedial myoclonus be evaluated?
Myoclonus of the stapedius or tensor tympani musculature is best detected using audiometric immitance testing. Changes in middle ear impedance can be objectively measured in the absence of external stimuli and often correlated subjectively by the patient with the perception of clicking.
What systemic diseases are associated with myoclonus?
What systemic diseases are associated with myoclonus?
Multiple sclerosis, cerebrovascular accidents, intracranial neoplasms, trauma, syphilis, malaria, various psychogenic causes, and other degenerative processes.
Describe the relationship between hearing loss and tinnitus.
Describe the relationship between hearing loss and tinnitus.
Most patients with tinnitus (about 85%) present with some degree of hearing loss, though not all patients with hearing loss develop tinnitus and all patients with tinnitus do not have abnormal hearing. About 10% of patients with tinnitus present with normal hearing.
What objective changes in otologic function have been found in patients with tinnitus and clinically “normal” hearing?
What objective changes in otologic function have been found in patients with tinnitus and clinically “normal” hearing?
Recent studies have found that tinnitus patients with hearing thresholds within audiometrically normal limits demonstrate significantly smaller amplitudes of wave I of the ABR than individuals with similar thresholds that do not have tinnitus (Schaette, 2013). This suggests that possible early cochlear damage causing reduced neuronal input may be a contributing factor to the development of tinnitus, even in patients with clinically normal hearing.
What is the relationship between noise exposure and tinnitus?
What is the relationship between noise exposure and tinnitus?
With brief, isolated exposure to loud noise, most individuals experience temporary partial loss in hearing sensitivity and tinnitus that disappears within hours or days of the exposure. Repetitive excessive exposure to noise increases the risk of these changes becoming permanent.
What is hyperacusis? What is the relationship between hyperacusis and tinnitus?
What is hyperacusis? What is the relationship between hyperacusis and tinnitus?
Hyperacusis is decreased tolerance to sound stimuli of normally comfortable sound level and pitch. Individuals who suffer from hyperacusis often report that typically soft stimuli or sounds of a certain pitch are unbearable or painful. Some researchers believe that tinnitus and hyperacusis are two manifestations of the same alterations in auditory processing associated with decreased cochlear input and that almost all patients with hyperacusis eventually experience tinnitus.
Which medications commonly cause tinnitus?
Which medications commonly cause tinnitus?
Tinnitus is a known potential side effect of many medications (for a complete list, see Table 34-1). The medications more commonly associated with tinnitus as a side effect are salicylates and aminoglycosides.
What are the effects of high-dose salicylates on tinnitus and hearing?
What are the effects of high-dose salicylates on tinnitus and hearing?
High serum concentrations of salicylates and some nonsteroidal anti-inflammatory drugs (NSAlDs) cause a flat, bilateral hearing loss and tinnitus. The hearing loss is a mild to moderate sensorineural hearing loss of about 20 to 40 dB. Incidence rate of salicylate-induced ototoxicity is less than 1%. Salicylates act as competitive inhibitors of chloride at the anion binding site of prestin, the motor protein of the outer hair cell, resulting in reversible alteration in outer hair cell function. Both hearing loss and tinnitus are reversible within 24 to 72 hours of discontinuation of the offending medication.
What percentage of patients with acoustic neuromas have tinnitus as the presenting symptom?
What percentage of patients with acoustic neuromas have tinnitus as the presenting symptom?
Ten percent of patients with acoustic neuromas present with tinnitus; however, over 80% have tinnitus at some point during the course of the disease.
How is auditory stimulation used in the treatment of tinnitus?
How is auditory stimulation used in the treatment of tinnitus?
Various methods of treatment involve the use of auditory stimulation. Most early forms of treatment relied on tinnitus masking, or the use of external sound stimuli to cover up or mask the tinnitus. Environmental sounds generators, radios, televisions, fans, and custom devices worn like hearing aids with broadband masking generators have all been used with varying degrees of success. Hearing aids have also been shown to aid in tinnitus reduction when the pitch of the tinnitus is within the amplification range of the device. Individualized sound stimulation devices focus on providing an enriched acoustic environment to compensate for hearing loss with musical stimuli of customized frequency spectrum.
