Ask the Audiologist

Sudden Hearing Loss

Sudden hearing loss syndrome is defined as a sudden decrease or loss of hearing in one or both ears. This may be preceded or accompanied by a static sound or ringing in the ears and/or dizziness up to 12 hours before or at the time the hearing loss occurs. Since a sudden hearing loss can be caused by a tumor of the inner ear, blockage of the blood supply to the inner ear, or a leak of inner ear fluid, it must be stressed that if any sudden change in hearing is noted, it is imperative to be seen within 24-48 hours by an ear, nose and throat doctor (Otolaryngologist).

Possible Causes
As there is often no clear cut etiology, the following are possible contributory causes: sudden pressure changes in the ear during airplane travel and scuba diving, unusual physical exertion or strain, previous ear surgery, recent upper respiratory infection, drugs such as birth control pills and antibiotics that are toxic to the ears, smoking, and acoustic trauma (sudden or prolonged loud noise exposure). In a majority of cases, the exact etiology is unknown and the underlying pathology is suspected to be due to problems with inner ear circulation. It is well known that patients have a better chance of recovery of the recent loss of hearing when seen early in the course of their ailment.

Assessment
An initial assessment of the patient who reports sudden hearing loss will include the following: History and ear, nose and throat examination, blood tests and audiological evaluation. Depending on the outcome of those tests, further tests may be recommended such as the auditory brainstem response test and a MRI scan of the inner ear.

The history may alert the ear, nose and throat doctor to situations which may have caused the loss, such as upper respiratory infection, air travel, scuba diving, history of smoking, the taking of birth control pills or other ototoxic medications and existing medical disorders.

The ear, nose and throat examination will show any abnormalities such as excessive wax in the outer ear canal, infection or fluid in the middle ear, or perforation of the eardrum.

Blood tests check for elevated levels of triglycerides and/or cholesterol, syphilis, infection, diabetes, thyroid and kidney disorders, inner ear infections and auto immune disease.

Audiological Evaluation
An Audiological evaluation will determine the degree, type and location of the hearing loss, whether it is a loss of the middle ear, inner ear or auditory nerve. In addition, testing will be completed to determine the ability to discriminate speech in quiet as well as in noise. Immittance testing may also be completed to assess the physical status of the eardrum and middle ear muscle reflexes. Special auditory tests, such as the auditory brainstem response test which measures the brain's responses to sound, and x-rays or an MRI scan, can serve to confirm the diagnoses or at least to rule out some possible causes for the symptoms.

Treatment
Treatment of sudden hearing loss varies, depending on the suspected cause. The patient may be given medicine to increase circulation of the inner ear and to reduce excessive fluid buildup in the middle or inner ear. Carbogen therapy, which increases the amount of oxygen to the inner ear, may be started if there is a suspected circulation problem of the inner ear. A specific regimen is indicated if there is fluid buildup in the middle or inner ear and surgery may be required for an inner ear tumor or a leak of inner ear fluid. The patient may be advised to stop the use of birth control pills, smoking, drugs, alcohol, caffeine, or to restrict the amount of strenuous activity, as well as to watch his intake of fats and cholesterol.

Prompt Action
In summary, anyone who notices any sudden diminution in hearing, regardless if there are any accompanying symptoms (fullness in the ears, ringing or dizziness), should be seen by their ear, nose and throat doctor within 24-48 hours. Recovery of the hearing loss depends not only upon the early diagnosis of the cause of the hearing loss, but also on the early initiation of appropriate treatment.