Cochlear implantation, a new technology that allows those with severe hearing-impairment to hear, is a form of surgery for patients with profound bilateral deafness who cannot benefit from conventional hearing aids.

Cochlear implantation involves a collaboration between specialists in otology (ear surgery) and speech, language, and hearing, and has offered patients suffering from a years of deafness a dramatic change - the chance to hear again.

The operation, which is usually done on an outpatient basis, involves implanting an electronic device behind the ear through the mastoid bone. The implant has an electrode array that is tunneled into the inner ear, next to the hearing nerve. When connected to an external microprocessor that resembles a hearing aid, the implant analyzes incoming sounds and produces a series of electrical impulses that directly stimulate the hearing nerve.

Cochlear implant surgery has achieved splendid results in properly selected patients, and is suitable for treating profoundly deaf adults and children one year of age and older. Certain patients have been able to gain the ability to hold conversations, often without lipreading; to speak on the telephone; and to hear environmental sounds.

Cochlear implant surgery requires a highly-trained team of specialists to provide the necessary postoperative programming of the implanted device and the rehabilitation that patients need on entering the world of sound.

How It Works
First, it is important to understand how the normal ear works. Sound waves enter the ear canal and vibrate the ear drum (tympanic membrane). Those vibrations are carried through the three small bones of the middle ear - the hammer (malleus), the anvil (incus), and the stirrup (stapes). The stirrup passes the vibrations to the inner ear fluids within the cochlea. Fluid waves travel through two-and-a-half turns of the cochlea, bending the cochlear hair cells as it passes. The cochlea has an array of hair cells, and each hair cell is tuned to a certain frequency, like the keys on a piano. The hair cells are like the spark plugs of the inner ear, and when stimulated by incoming sound, they initiate a signal within their corresponding nerve ending that is then sent to the brain where the sound is recognized.

Most deafness is caused by loss of hair cells. However, the nerve endings are still purposeful in most of these cases; thus, it is possible for cochlear implants to work. A cochlear implant is an electronic device that restores auditory sensation by stimulating the auditory nerve electrically, bypassing the hair cells. Cochlear implantation is appropriate for patients 12 months of age and older with severe hearing impairment who cannot benefit from hearing aids. The implant provides a wide range of auditory information needed for recognizing speech, music, and environmental sounds.

How Otosclerosis Causes Hearing Loss
In normal hearing, sound (which is the vibration of air) causes the eardrum to vibrate, and those impulses are carried to the inner ear through three small bones (malleus, incus, and stapes).
The stapes vibrates like a piston and transforms the air vibrations of sound into fluid vibrations in the inner ear or cochlea. The fluid vibrations in the cochlea are captured by nerves which transmit the sensation of sound to the brain.

Otosclerosis is a genetic disorder that affects the bone of the inner ear. The character of the bone changes from dense ivory to brittle and chalky. This abnormal bone forms around the base of the stapes and prevents it from vibrating properly, causing a decrease in hearing.

How Otosclerosis Is Detected

Otosclerosis causes a characteristic type of hearing loss, which is mechanical or “conductive.”  This can be identified by a hearing test. Besides hearing loss, otosclerosis sometimes causes ringing or noise in the ear and dizziness or imbalance.

Who Gets Otosclerosis

Otosclerosis is usually first detected in the young adult years when the hearing loss first develops. If left alone, the hearing loss gets slowly worse over time. Both ears are usually involved to some extent. However, in some individuals, only one ear is affected.

Otosclerosis is a hereditary disorder; the tendency to develop otosclerosis is carried in the genes and handed down from parent to child. Sometimes it skips generations, so that not all family members are affected. It tends to affect females more than males.

How Otosclerosis Can Be Treated

Treatment options include surgery or a hearing aid. Either treatment is elective. No medication has been shown to be effective in restoring hearing.

Stapedectomy surgery has been performed since the 1950s and has provided excellent results to many patients over the years.

How Stapedectomy Surgery Is Performed

The procedure is usually performed in hospital, in the operating room, on an outpatient basis. The operation is done through a microscope because the hearing bones are very small.

The operation is performed through the natural ear opening. An incision is made, and the eardrum is raised up away from the bone. The stapes is separated from the incus bone, and then the stapes is removed.

A prosthesis made of plastic or wire is then inserted into the ear in place of the stapes. This prosthesis conducts the vibrations of sound to the inner ear. In this way, hearing is restored.

Care Required After Surgery
Hearing usually starts to return about a week after surgery and can improve for up to three months after surgery. A clot forms and is removed from the ear after one week.

Patients usually go home the same day as the surgery and are encouraged to rest for the first week. Light activity, like walking, is permissible. Strenuous activity, such as jogging or lifting heavy objects, should be avoided for about three weeks. Patients who have desk jobs may return to work after one week. Patients who have jobs which require physical activity or lifting usually may return to work after about two weeks.

It is important to avoid getting the ear wet after surgery. Showering is allowed, but the ear must be covered with a cotton ball with Vaseline. Blowing the nose should be avoided for one week. Airplane trips should be avoided for at least three weeks.

Chances of Success

In general, the operation is successful in restoring hearing in 9 out of 10 cases. In most cases, the gain in hearing is permanent. In about 1 out of 10 cases, there is no improvement in the hearing. There are about 2 chances out of 100 of having permanent hearing loss. There is about 1 chance out of 100 that hearing loss would be so severe that a hearing aid could not be used in the ear.

Risks of Stapedectomy

Any surgery performed on the body has certain risks. While most of these risks are not common, it is important to mention them before deciding to have a surgical operation. It is important for patients to understand that no surgeon can ever guarantee results. Surgical risks can include the following:

• Hearing loss: As mentioned above, surgery usually, but not always, results in improvement in hearing. Further loss of hearing or compete deafness is uncommon but may occur
• Dizziness: Temporary dizziness may occur after surgery. It usually passes within one week, and limitation of movement is recommended until it subsides. Rarely is dizziness prolonged
• Alteration of taste: An unusual taste or dry mouth on the side of surgery may occur. This is usually temporary, but may last a few months. In rare instances this is permanent
• Eardrum perforation: Small tears may occur when handling the eardrum. Sometimes a second, smaller operation is necessary to repair a perforation
• Infection: Infection in the ear resulting in a loss or hearing or perforation of the eardrum may rarely occur
• Tinnitus: Tinnitus, or ringing in the ear, may continue after surgery. In rare cases it may get worse after surgery
• Facial weakness: The facial nerve is an important structure that travels near the stapes. Temporary facial weakness is an uncommon complication. Permanent facial weakness rarely occurs
• Anesthesia complications: Any type of anesthesia may cause complications, but these are fortunately quite rare. The anesthesiologist will discuss this before the time of surgery

Sudden hearing loss is defined as a loss of hearing that begins for no apparent reason and develops over 24 hours or less. The hearing loss arises in the hearing organ of the inner ear (cochlea) or in the hearing nerve. Despite the fact that this is a relatively common disease, much is still unknown about its cause, treatment, and prognosis.

The possible mechanisms of sudden hearing loss include viral infection, stroke or loss of blood flow (ischemia) to the inner ear, or membrane rupture of the inner ear. Occasionally, another underlying ear problem can present with sudden hearing loss, such as Meniere’s disease (a derangement of fluid balance in the inner ear), autoimmune inner ear disease (AIED, an antibody directed at the tissues of the inner ear), or a tumor of the hearing nerve (acoustic neuroma). Tumors are decidedly rare, occurring in about 2 percent of cases, and can be ruled out by MRI. AIED runs an up-and-down course and usually involves both ears. Meniere’s disease causes fluctuating hearing, tinnitus, and vertigo, and the diagnosis becomes obvious over time.

Patients with sudden hearing loss should undergo audiogram, laboratory testing, and MRI.  Based on the results of these tests, a cause can be presumed, and the appropriate treatment is started. Virus is the most common cause. Steroids (cortisone), taken orally over one to two weeks, are often, but not always, beneficial. There has been recent enthusiasm for injecting steroids directly into the ear, a procedure whose value is still under investigation. Steroid injection achieves higher doses in the inner ear fluids, but it is not clear what the best dose is, and how often it should be given. Antivirals have also been used, but two well-controlled studies have failed to show any benefit. Stroke or ischemia can be treated with blood thinners. Inner-ear membrane rupture is treated with bedrest; in certain cases, surgical exploration and patching of the inner-ear membrane may be recommended, a procedure with low risk but uncertain benefit. AIED is treated with steroids or immune suppressants, Meniere’s disease with diuretics and low-salt diet, and acoustic neuroma with surgery or radiotherapy.

The chance that the hearing will recover is never certain, but there are a few predictive factors. Severe or profound losses have a lower chance of recovery than milder losses.  Vertigo, when it accompanies the hearing loss, is a poor prognostic sign. Treatments are most effective when started as early as possible after the onset of the loss; unfortunately, some patients don’t regain their hearing.

Sudden hearing loss is a distressing disease that begins without warning. Most cases are viral, and most patients are treated with steroids. This disease continues to be vexing for both doctor and patient, and because the cause cannot often be determined, the treatment is not always effective, and the prognosis is usually not known. 

A Bone Conduction Hearing Aid and a Bone Anchored Hearing Aid (BAHA) are for those requiring a hearing aid who have good inner ear "nerve" function, but cannot use a conventional hearing aid. The BAHA required a minor surgical procedure.

Some examples of assistive listening devices include:

• Telephone devices for the deaf (TDD)
• Infra-red listening devices for the theater, movies, television
• Alerting devices such as lights flashing when the doorbell or telephone rings; the bed shaking when the alarm clock or smoke detector sounds
• Telephone amplifiers