Tinnitus

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• Sequential and coexisting bilateral suboccipital cavernous sinus arteriovenous fistulas successfully treated with unilateral transvenous coil embolization: illustrative case
• Noise and the risk of tinnitus: A two-sample Mendelian randomized study
• Optimal Dosing of Nortriptyline-Topiramate and Verapamil-Paroxetine Combinations in Tinnitus Treatment
• Complex Cerebral Artery Anomaly Rete-like Formation of the Terminal Carotid and Middle Cerebral Arteries with Bilateral A1 Segments Fenestrations
• Subdural Hematoma Presenting with Tinnitus After Spinal Anesthesia for Cesarean Section: A Case Report
• Endovascular Treatment of Direct Carotid-Cavernous Fistula in a Patient with Loeys-Dietz Syndrome
• Innovation under pressure: Managing a complex carotid-jugular fistula in a war-zone limited-resources area

May be either subjective (heard only by patient) or objective (e.g. cranial bruit, can be heard by the examiner as well, usually with a stethoscope placed over the cranium, orbit, or carotid arteries in the neck). Objective tinnitus is almost always due to vascular turbulence (from increased flow or partial obstruction).

Tinnitus is the conscious, usually unwanted perception of sound that arises or seems to arise involuntarily in the ear of the affected individual. In most cases there is no genuine physical source of sound. This nonpulsatile tinnitus is caused by a hearing malfunction.

see Pulsatile tinnitus.

see Non-pulsatile tinnitus.

Tinnitus Etiology.

Tinnitus may be an accompaniment of sensorineural hearing loss or congenital hearing loss, or it may be observed as a side effect of certain medications (ototoxic tinnitus).

Tinnitus is usually a subjective phenomenon, such that it cannot be objectively measured. The condition is often rated clinically on a simple scale from “slight” to “catastrophic” according to the difficulties it imposes, such as interference with sleep, quiet activities, and normal daily activities.

Tinnitus and hearing loss in the adult can have profound effects on the quality of life. The imaging workup for tinnitus and hearing loss in adults follows otoscopic exam and audiometry testing. CT and MR imaging have different and often complementary roles in the evaluation of tinnitus and hearing loss depending on the clinical scenario and the suspected underlying cause. Imaging can often identify the cause and evaluate the extent of disease for surgical planning ¹⁾.

Tinnitus Handicap Inventory.

see Tinnitus treatment.

Bayesian models of brain function such as active inference and predictive coding offer a general theoretical framework with which to explain several aspects of normal and disordered brain function. Of particular interest to a study is the potential for such models to explain the pathology of auditory phantom perception, i.e. tinnitus. To test this framework empirically, Hullfish et al., performed an fMRI experiment on a large clinical sample (n = 75) of the human chronic tinnitus population. The experiment features a within-subject design based on two experimental conditions: subjects were presented with sound stimuli matched to their tinnitus frequency (TF) as well as similar stimuli presented at a control frequency (CF). The responses elicited by these stimuli, as measured using both activity and functional connectivity, were then analyzed both within and between conditions. Given the Bayesian-brain framework, they hypothesized that TF stimuli will elicit greater activity and/or functional connectivity in areas related to the cognitive and emotional aspects of tinnitus, i.e. tinnitus-related distress. They conversely hypothesize that CF stimuli will elicit greater activity/connectivity in areas related to auditory perception and attention. They discuss this results in the context of this framework and suggest future directions for empirical testing ²⁾.

Rodent models of tinnitus are commonly used to study its mechanisms and potential treatments. Tinnitus can be identified by changes in the gap-induced prepulse inhibition of the acoustic startle reflex (GPIAS), most commonly by using pressure detectors to measure the whole-body startle reflex (WBS). Unfortunately, the WBS habituates quickly, the measuring system can introduce mechanical oscillations and the response shows considerable variability.

Wallace et al. have instead used a motion tracking system to measure the localized motion of small reflective markers in response to an acoustic startle reflex in guinea pigs and mice. For guinea pigs, the pinna had the largest responses both in terms of displacement between pairs of markers and in terms of the speed of the reflex movement. Smaller, but still reliable responses were observed with markers on the thorax, abdomen and back. The peak speed of the pinna reflex was the most sensitive measure for calculating GPIAS in the guinea pig. Recording the pinna reflex in mice proved impractical due to removal of the markers during grooming. However, recordings from their back and tail allowed us to measure the peak speed and the twitch amplitude (area under curve) of reflex responses and both analysis methods showed robust GPIAS. When mice were administered high doses of sodium salicylate, which induces tinnitus in humans, there was a significant reduction in GPIAS, consistent with the presence of tinnitus. Thus, measurement of the peak speed or twitch amplitude of pinna, back and tail markers provides a reliable assessment of tinnitus in rodents ³⁾