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  • Updated 05.14.2024
  • Released 09.17.2001
  • Expires For CME 05.14.2027

Subjective tinnitus

Introduction

Overview

The author explains the clinical presentation, pathophysiology, diagnostic work-up, and management of subjective tinnitus. Studies have demonstrated that subjective tinnitus is associated with hyperactivity of the auditory cortices integrated in a global network of long-range cortical connectivity involving the prefrontal cortex, orbitofrontal cortex, and the parieto-occipital region; signals from the global network on the temporal areas correlate with the subjective strength of the tinnitus distress. Although pharmacologic treatments have generally been disappointing in patients with subjective tinnitus, anecdotal reports suggest that low-dose carbamazepine can relieve symptoms in patients with specific auditory hyperactivity disorders of the eighth nerve (eg, so-called "typewriter tinnitus" and "paroxysmal staccato tinnitus") possibly resulting from neurovascular compression akin to trigeminal neuralgia and hemifacial spasm.

Key points

• Subjective tinnitus is a perceived sensation of sound that occurs in the absence of external acoustic stimulation and cannot be heard by the examiner. Most tinnitus is subjective.

• One third of adults experience tinnitus during their lives; at least 10% of those develop prolonged tinnitus requiring medical evaluation.

• The tinnitus associated with Meniere syndrome is typically low-pitched (below 1000 Hz, and usually 125 to 500 Hz). When associated with middle-ear disease (including otosclerosis), it is typically low- or mid-range in frequency (250 to 2000 Hz); when associated with acoustic trauma or noise exposure, it is typically around 4000 Hz; when associated with presbycusis, acoustic neuroma, ototoxicity, and other sensorineural causes, it is typically high-pitched (2000 Hz and greater); and when associated with normal hearing, tinnitus of any frequency can occur.

• Tinnitus is frequently associated with depression (in up to half of patients) as well as anxiety, annoyance, anger, frustration, and insomnia.

• Although subjective tinnitus may occur with a wide variety of lesions of the external ear, middle ear, cochlea, auditory nerve, or central nervous system, it occurs most commonly as a result of cochlear dysfunction.

• The most commonly identified causal factor for subjective tinnitus is noise-induced hearing loss. The prevention of noise-induced hearing loss is essential, as most cases of subjective tinnitus cannot be cured, and many are refractory to treatment.

• An important treatable cause of subjective tinnitus is otosyphilis.

• Unilateral subjective tinnitus associated with progressive sensorineural hearing loss should suggest the possibility of an acoustic neuroma or other eighth nerve lesion.

• Anecdotal reports suggest that low-dose carbamazepine, although not generally effective for subjective tinnitus, can relieve symptoms in patients with specific auditory hyperactivity disorders of the eighth nerve (eg, so-called "typewriter tinnitus" and "paroxysmal staccato tinnitus") possibly resulting from neurovascular compression akin to trigeminal neuralgia and hemifacial spasm.

Historical note and terminology

The word tinnitus is derived from the Latin tinnire, which means “to ring.” Subjective tinnitus is a perceived sensation of sound that occurs in the absence of external acoustic stimulation and cannot be heard by the examiner. Subjective tinnitus is usually described as ringing, buzzing, roaring, or clicking. It is distinct from objective tinnitus (ie, tinnitus heard by the examiner) as well as more complex sounds characteristic of auditory hallucinations (eg, voices and music). Most tinnitus is subjective.

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