Sensorineural Hearing Loss

What is sensorineural hearing loss?

Sensorineural hearing loss occurs when something damages the inner ear, the auditory (hearing) nerve, or the parts of the brain that process sound.

How the ear works

The ear is made up of 3 main parts:

1. Outer ear
2. Middle ear
3. Inner ear
   

• The outer ear extends from the outside part of the ear, which you can touch, to the ear drum. Sound waves enter the ear through the outer ear. The outer ear directs sound toward the ear drum, which separates the outer ear from the middle ear.
• When sounds reach the ear drum, they pass through to the middle ear, which is normally filled with air. Inside the middle ear, there are three small bones that connect to form a chain. The first bone is connected to the ear drum and the last bone is connected to a small membrane called the oval window. When sound hits the ear drum, the 3 tiny bones are set in motion, and the last one pushes on the oval window.
• The inner ear has the fluid-filled cochlea. Tiny nerve endings, called sensory hair cells, line the cochlea. Hair cells change sound waves into nerve impulses. These signals travel along the auditory nerve to the brain. The brain processes the nerve signals and makes meaning of the sound.

Causes of sensorineural hearing loss

Sensorineural hearing loss includes 2 types of hearing loss: sensory hearing loss and neural hearing loss.

• Sensory hearing loss occurs when the cochlea or the tiny hair cells are damaged.
• Neural hearing loss occurs when there is damage to the hearing nerve or to the part of the brain responsible for hearing.

Sensorineural hearing loss usually starts in the high frequencies (high pitches). As more damage occurs, the hearing in the lower frequencies may become worse.

Sometimes it is hard to know whether the problem is sensory, neural, or both. That is why we often use the general term sensorineural hearing loss.

Sensorineural hearing loss can have many different causes. For children with cancer or other illnesses, sensorineural hearing loss can be caused by treatments or the effects of the disease.

Chemotherapy

The most common types of chemotherapy that cause hearing loss are platinum-based medicines such as cisplatin or carboplatin.

Chemotherapy drugs can be absorbed into the fluid that surrounds the hair cells. This causes damage to the hair cells and keeps them from working properly. The hair cells cannot send signals to the brain, and it is harder to hear certain sounds.

Radiation

Radiation can cause sensorineural hearing loss in 2 different ways. Radiation may damage the hair cells, like chemotherapy does. Radiation can also damage the area of the brain that interprets sound or can harm the nerves that send signals between the hair cells and the brain.

Surgery or tumors

Surgery can damage nerves or brain areas involved in hearing. The hearing nerve can be bruised or even cut. Pressure from swelling (edema) or a tumor can keep the hearing nerve from working properly.

Treatment for sensorineural hearing loss

If your child is at risk for hearing loss or has symptoms of hearing loss, the first step is to see an audiologist. An audiologist is a health care provider who specializes in hearing care. A hearing test can help determine the type of hearing loss and how severe it is. Your audiologist and doctor will help develop the best plan for your child’s hearing needs. If a hearing aid or other device is needed, an audiologist can help select the right device and fit it for your child.

Learn more about Audiology and Hearing Care.

Find more information on hearing loss including types of hearing loss, symptoms of hearing loss, and ways to cope with hearing loss.