Tinnitus

Tinnitus is perception of sound in one or both ears without an external stimulus. Usually, tinnitus is heard only by the patient (subjective tinnitus). Rarely, it is caused by some internal sound (almost always a vascular bruit or related to cervical or temporomandibular joint arthritis) that may be heard by the examiner as well (objective tinnitus). Diagnosis is based on history and examination and audiometry in most patients, but Hct or Hb, magnetic resonance angiography and magnetic resonance venography, and brain MRI are indicated in all patients with pulsatile tinnitus. Treatment for tinnitus caused by sensorineural hearing loss starts with patient education and a well-fitted hearing aid. Tinnitus attributed to other underlying disorders may be ameliorated by treating the underlying disorder.

Geriatric Essentials

• Tinnitus in the elderly is usually subjective, bilateral, and continuous.
• Tinnitus in the elderly is usually caused by sensorineural hearing loss.
• Tinnitus in the elderly may be a sign of undiagnosed or undertreated depression or anxiety.

About 15 to 20% of all adults report spontaneous tinnitus lasting > 5 min, and 10 to 14% have prolonged (ie, more than just transient) tinnitus. About 25% of elderly adults have prolonged tinnitus. Tinnitus is bothersome but does not impair function; consequently, people who have tinnitus usually do not seek treatment. Of those who do seek treatment, most are satisfied with reassurance after their evaluation. However, tinnitus is extremely bothersome to about 14% of adult patients and interferes with daily activities in about 4 to 6%.

Etiology

Usually, tinnitus results from hearing loss, and all types of hearing loss can cause subjective tinnitus. Because the prevalence of hearing loss increases with aging, so does the prevalence of tinnitus.

Tinnitus may also be caused by disorders that do not cause hearing loss and by certain drugs (see Table 129-1). Vascular disorders (eg, anemia or disorders that alter blood flow in vessels close to the ear) may cause objective tinnitus by generating detectable sounds (eg, venous hum). Depression, often associated with significant life stress (ie, retirement, death of a spouse, problems with sexual function), may aggravate tinnitus of any type.

Pathophysiology

The pathophysiology of tinnitus resulting from hearing loss is unknown but may resemble that of phantom limb sensation, in which sensations are perceived to originate from an amputated limb. Auditory deprivation, regardless of cause, may lead to the generation of a perceived sensation (tinnitus) by central auditory structures. In support of this theory, tinnitus most commonly affects people whose hearing loss is acquired. According to another theory, tinnitus resembles crosstalk between telephone wires: Patchy loss of myelin from the auditory nerve results in signals crossing from one auditory fiber to another.

Symptoms and Signs

Tinnitus manifests similarly in elderly and younger patients. Tinnitus is usually subjective, bilateral, and continuous. However, both subjective and objective tinnitus can be unilateral or episodic. Subjective tinnitus is described as a ringing, buzzing, hissing, or whistling sound that resembles bells, crickets, or a variety of complex sounds. Objective tinnitus often has a pulsatile quality. In most elderly patients, sensorineural hearing loss coexists. Elderly patients with long-standing hearing loss may seek treatment only when tinnitus becomes bothersome.

Diagnosis

History and physical examination may help distinguish subjective from objective tinnitus, determine the cause, or suggest a testing strategy. The patient should be asked about onset (ie, acute, subacute, chronic), quality (ie, continuous or intermittent, bilateral or unilateral, whether it is pulsatile), exacerbating factors (eg, quiet surroundings, stress), alleviating factors (eg, background noise), and effects on normal activities (eg, insomnia, distraction). Hearing status; history of exposure to ototoxic drugs (eg, salicylates, aminoglycosides, cisplatin, quinine); and history of occupational, military, or recreational noise exposure are determined. Determining whether tinnitus is related to depression is sometimes necessary. Clues linking the two include insomnia that the patient relates to the tinnitus, early awakening, and a disproportionately high level of distraction ascribed to the tinnitus.

Examination of the ear may detect a perforated tympanic membrane or middle ear effusion. Tuning fork tests may distinguish between sensorineural hearing loss and conductive hearing loss. Auscultation of the precordium and neck and over the temporal bone may detect a bruit in patients complaining of pulsatile tinnitus that matches their heartbeat.

Audiometry, including pure-tone air and bone thresholds and speech audiometry, should be done in all patients with tinnitus. If sensorineural hearing loss is asymmetric or if tinnitus is considerably worse in one ear, the physician should look for a retrocochlear abnormality (eg, acoustic neuroma). For the oldest old with multiple comorbid disorders that limit function and for those >= 65 with life-threatening comorbid disorders, auditory brainstem response (ABR) or brainstem auditory evoked response (BAER) testing may be sufficient to screen for lesions that warrant treatment as long as residual hearing is adequate to obtain a reliable test result. Patients with a normal ABR should have a repeat hearing test, ABR test, or both in 6 to 12 mo. For all other patients, particularly those with other symptoms (eg, vertigo), gadolinium-enhanced MRI with fine cuts through the internal auditory canals should be done.

Hb or Hct is required if tinnitus is pulsatile because treating anemia may stop pulsatile tinnitus. Other blood tests are useful only if indicated by other symptoms or signs (eg, if a hyperdynamic state resulting from hyperthyroidism is suspected). If the patient has a carotid bruit and ipsilateral pulsatile tinnitus, ultrasonography of the carotid system is indicated to rule out arterial obstruction, aneurysms, and vascular neoplasms. If a vascular mass (a glomus tumor or high-positioned jugular bulb) is detected in the middle ear, high-resolution CT of the temporal bone is required to determine the origin of the mass. If patients have subjective or objective pulsatile tinnitus and no other causes detected (eg, no anemia or carotid obstruction), magnetic resonance angiography (MRA) and magnetic resonance venography (MRV) of the cerebral vasculature as well as brain MRI should be done. If MRA, MRV, or MRI is normal (or when MRI cannot be done) in patients with objective arterial pulsatile tinnitus, cerebral angiography is required because MRA and MRV may not show dural arteriovenous malformations and fibromuscular dysplasia.

Treatment

For patients with tinnitus caused by sensorineural hearing loss, the most effective treatment is usually a well-fitted, well-adjusted hearing aid, which greatly reduces tinnitus for many patients. Reassuring patients with tinnitus caused by sensorineural hearing loss that no life-threatening underlying disorder exists may alleviate anxiety.

Treating underlying disorders other than sensorineural hearing loss may cure or alleviate tinnitus (see Table 129-1).

Regardless of cause, patients bothered by tinnitus primarily at night benefit from a white-noise generator at bedside (or a radio tuned to an interband FM frequency). Tinnitus maskers, worn in the ear similarly to hearing aids, generate a band of noise corresponding to the patient's tinnitus and are occasionally helpful.

Biofeedback is effective for selected patients who have distressing tinnitus unrelieved by other measures. Patients with tinnitus and depression or anxiety require appropriate counseling and drug treatment.

This topic was last updated June 2006.