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.
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.
