Tinnitus is the perception of sound in the ears or head, where no external source of the sound exists. It is usually subjective, meaning only the patient can hear it, and is associated with hearing loss on the affected side. Its prevalence increases with age, so that about 10% of people aged over 60 experience some form of tinnitus.
Clinical examination of the ears, cranial nerves and neck is recommended, but routine brain imaging is not. Blood tests are rarely helpful in tinnitus. Acoustic neuromata are a rare cause of unilateral tinnitus. It can be caused by medications used to treat hypertension, but is generally not caused by the hypertension itself.
Medications and surgery have generally been found to be ineffective: the most effective remedies are tinnitus retraining therapy and tinnitus maskers. Early referral to audiology is therefore recommended.
It can be divided into two main types:
This is by far the most common type of tinnitus, where there is no acoustic stimulus. Common causes are:
- Otological: noise-induced and other forms of hearing loss, presbyacusis, otosclerosis, impacted cerumen, ear infection, Ménière's disease.
- Neurological: head injury, multiple sclerosis, acoustic neuroma and other similar tumours.
- Infectious: meningitis, syphilis.
- Drug-related: salicylates, non-steroidal anti-inflammatory drugs (NSAIDs), aminoglycosides, loop diuretics, cytotoxicity.
- Jaw disorders: temporomandibular joint dysfunction.
Many cases of tinnitus have no identifiable cause.
Many doctors are concerned that their patient with tinnitus could have an acoustic neuroma (also known as a vestibular schwannoma) but in fact acoustic neuromata are rare, with an incidence of just 1 per 100,000 people per year. They also tend to present with unilateral sensorineural hearing loss, not necessarily with tinnitus. Overall, only 2% of patients with unilateral tinnitus along with sensorineural hearing loss will prove to have a vestibular schwannoma.
This is rare and occurs when there is actually a noise to be heard being generated within the head. These can be:
- Pulsatile: due to movement of blood - eg, carotid stenosis, vascular anomalies or tumours, valvular heart disease, high cardiac output states.
- Muscular or anatomical: palatal myoclonus, spasm of tympanic muscles, patulous Eustachian tube.
- Spontaneous: otoacoustic emissions.
The prevalence of tinnitus goes up with age: it occurs in 1.6% of people aged 18-44; 4.6% of people aged 45-64; and 9% of people aged over 60.
However, it is thought to occur in children who have co-existing hearing problems. Because tinnitus is difficult for children to describe, it is hard to obtain accurate data. The question 'can you hear a noise inside your ears or head?' has been answered 'yes' by over a third of school-age children, which seems like an unnaturally high prevalence.
It is the most prevalent service-related disability for US military veterans receiving compensation, resulting in nearly 1 million veterans receiving disability awards.
Data from the 1980s involving small numbers of patients showed that those with tinnitus report depression at a far higher rate than non-tinnitus patientsalthough more recent data have shown only a weak association between tinnitus and depression. There is no firm association between tinnitus and suicide.
Patients often take a long time before seeking medical attention. Most common sounds are:
The condition is reported to be unilateral in 22%, equal in both ears in 34% and one side dominant in the rest, usually the left.
Examination and investigations
- Thorough examination of the head, neck, ears and jaw should be made. Although most patients with tinnitus will have a normal clinical examination, it is important to check for:
- Impacted earwax (which can sometimes cause tinnitus and is easily rectified).
- Carotid bruit (in the case of pulsatile tinnitus).
- Cranial nerve defects (which can signify a neoplasm in the brainstem or posterior nasopharynx).
- Otitis media (although of course the patient will have ear pain too).
- Masses or glands up in the neck, or behind the ear (which can signify a neoplasm).
- A formal hearing test is recommended. This is because hearing loss is commonly associated with tinnitus and may be the cause of it. Treating the hearing loss with a hearing aid may help to alleviate the tinnitus.
- Hypertension is not thought to cause tinnitus. However, slightly more people with tinnitus have hypertension than do not. This may be because of the ototoxicity of the drugs used to treat the hypertension (ACE-inhibitors, diuretics, calcium-channel blockers, potassium-sparing diuretics and aspirin all have a weak association with tinnitus).
- Routine brain imaging for bilateral tinnitus is not recommended.
- The history should include an enquiry about depression or anxiety, which can worsen tinnitus. Alleviating the underlying emotional health problem can help with the tinnitus.
Although patients report sound as being loud, hearing tests demonstrate that they are at an intensity that is only just louder than the softest sound audible at that frequency - usually above 3 kHz.
- Explanation and reassurance that the condition will not progress and that there are no sinister findings.
- There is a strong association between tinnitus and stress; relaxation techniques or relaxing background music can distract or mask some tinnitus.
- Tinnitus retraining therapy shows improvement in 75-82% of patients. It links negative emotional associations with tinnitus-related neural activity[10, 11]. It may take over a year to complete the therapy, with a goal of habituating the patient to the tinnitus rather than abolishing it. Results are sustained in the long term.
- Masking devices can be used in those patients who obtained relief from masking during the hearing test. Tinnitus maskers create and deliver constant low-level white noise to the ear. Patients should be advised to wear the device during their waking hours, but successful wearers may wear the device while sleeping.
The high success rates of retraining therapy and masking therapy, compared to medications and surgery, along with the low risk of side-effects, emphasises the importance of early referral to audiology for patients with troubling symptoms.
Patients who have experienced tinnitus for a while are often desperate for a treatment to help alleviate the noise. The doctor is often equally as desperate. Some older studies have made tentative suggestions that selective serotonin reuptake inhibitors (SSRIs), tricyclics or nasal lidocaine can help tinnitusbut many of the proposed treatments, when subjected to placebo-controlled trials, were found to be ineffective.
This led to 2014 guidance from a US tinnitus development group to recommend against:
- Intratympanic medication
- Ginkgo biloba
- Transcranial magnetic stimulation
Small case series have shown equivocal benefit from microvascular decompression of the cochlear nerve. The current available data show that, in patients with severe tinnitus and associated findings on imaging, about 18% show total relief after surgery, 46% have no improvement, but 3% are rendered worse.
Further reading and references
; British Tinnitus Association, February 2017
; Asymmetric hearing loss: rule 3,000 for screening vestibular schwannoma. Otol Neurotol. 2009 Jun30(4):515-21. doi: 10.1097/MAO.0b013e3181a5297a.
; Tinnitus: its causes, diagnosis, and treatment. BMJ. 1993 Jun 5306(6891):1490-1.
; Clinical practice guideline: tinnitus. Otolaryngol Head Neck Surg. 2014 Oct151(2 Suppl):S1-S40. doi: 10.1177/0194599814545325.
; Tinnitus in children and associated risk factors. Prog Brain Res. 2007166:179-91. doi: 10.1016/S0079-6123(07)66016-6.
; Chronic tinnitus: association with psychiatric diagnoses. J Psychosom Res. 198731(5):613-21.
; Relationship between tinnitus severity and psychiatric disorders. Psychosomatics. 2006 Jul-Aug47(4):282-8. doi: 10.1176/appi.psy.47.4.282.
; Tinnitus and suicide. Clin Otolaryngol Allied Sci. 1994 Feb19(1):50-4.
; Tinnitus - a study of its prevalence and characteristics. Br J Audiol. 1989 Feb23(1):53-62.
; Positive Association between Tinnitus and Arterial Hypertension. Front Neurol. 2016 Oct 57:171. doi: 10.3389/fneur.2016.00171. eCollection 2016.
; Patient-based outcomes in patients with primary tinnitus undergoing tinnitus retraining therapy. Arch Otolaryngol Head Neck Surg. 2002 Oct128(10):1153-7.
; Long-term clinical trial of tinnitus retraining therapy. Otolaryngol Head Neck Surg. 2005 Nov133(5):774-9.
; Long-Term Improvement in Tinnitus after Modified Tinnitus Retraining Therapy Enhanced by a Variety of Psychological Approaches. Audiol Neurootol. 2009 Aug 415(2):69-80.
; Long-term effectiveness of ear-level devices for tinnitus. Otolaryngol Head Neck Surg. 2006 Jan134(1):132-137.
; Emerging pharmacotherapy of tinnitus. Expert Opin Emerg Drugs. 2009 Aug 27.
; Microvascular decompression operations. Prog Brain Res. 2007166:397-400. doi: 10.1016/S0079-6123(07)66038-5.