Sudden hearing loss without any apparent cause, contrasting against a noise induced hearing loss as a result of exposure to excessive workplace noise, has been the subject of research into causes and finding better treatments with fewer side effects.To date, a standard treatment is to use oral steroids, but recent studies suggest that administering by injection can produce equally effective results.

The condition affecting one ear, occurs suddenly in less than 72 hours, although intermittent symptoms of tinnitus (ringing, whistling or rushing sounds), sometimes accompanied by intense pressure or ‘fullness’, dizziness or vertigo can be experienced in the preceding weeks. Although the condition can occur at any age, the highest incidence, affecting both males and females, are aged 45 to 55.

Around a quarter to a third of all individuals who suffer sudden hearing loss will find their condition will improve by itself although hearing might not return exactly to a normal level. Prompt treatment has shown that the chances of improvement rise to half or more in many cases.

Loss of hearing is commonly attributable to being either conductive, in which sound vibrations are blocked from reaching the inner ear, e.g. by ear wax, or sensorineural, when sound vibrations reach the inner ear but hearing damage to the hair cells means signals are no longer able to reach the brain.

However, the direct cause of sudden hearing loss has yet to be adequately understood. Several different explanations have been put forward, including varieties of impaired blood flow to the inner ear such as vascular insufficiency, embolism, thrombosis, or viral infection. In addition, no single test is available and a clinical diagnosis must carefully deliberate over the symptoms present and consider all possible causes before advising a treatment type.

Typical treatment is via oral steroids, which can be accompanied by a variety of side effects such as insomnia, weight gain and an increase in blood sugar levels. New comparison studies have been conducted, which treated patients with sudden hearing loss with a either a two-week course of oral steroids or four steroid injections spaced out over two weeks, delivered through the eardrum and into the middle ear.

Prior to the study, a hearing test showed that patients suffered at least a 50 decibel hearing loss in one of their ears. Test results conducted two months following the study showed that patients treated with oral steroids had an average 30.7 decibel improvement, compared to a 28.7 decibel improvement in those treated with injections, and thus the latter appeared to be equally effective.