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Some people may develop hearing problems as a late effect of treatments for cancer during childhood. Treatments that can lead to hearing damage or loss include certain chemotherapy drugs, other medicines and radiation therapy.
The ears collect sound, process it and send signals to the brain. They also help with balance. Each ear is made up of 3 main parts.
The outer ear includes the visible part of the ear, which collects sound. It also includes the ear canal, where wax is made. Earwax helps fight infections by collecting dirt to keep the ear canal clean.
The middle ear has the eardrum. Sound waves are turned into vibrations as they move through the eardrum to the inner ear. The middle ear also contains the Eustachian tube. It lies in the skull base between the nasal cavity and the inner ear. It connects to the upper part of the throat. The Eustachian tube balances the air pressure in the ear so that it is the same on both sides of the eardrum.
The inner ear has the cochlea, which is a small, curled tube that is filled with liquid and lined with tiny hairs. When sound reaches the cochlea, the vibrations cause the hairs to move, creating nerve signals that are transmitted to the brain.
Hearing loss may be conductive, sensorineural or mixed (both conductive and sensorineural).
Conductive hearing loss
Conductive hearing loss occurs when sound from the environment can’t travel to the inner ear because there is a problem with the outer or middle ear.
Conductive hearing loss is usually caused by problems with the Eustachian tube in the middle ear (called Eustachian tube dysfunction). If it doesn’t open enough, the pressure in the middle ear changes. If it stays closed, fluid will fill the middle ear.
Conductive hearing loss can be treated. Hearing usually returns to normal after the problem causing hearing loss is treated.
Sensorineural hearing loss
Hearing loss occurs when there is damage to the cochlea or auditory nerve in the inner ear or the part of the brain that processes sound.
High-pitch sounds are usually the first to be affected if there is sensorineural hearing loss. Middle- and lower-pitch sounds can also be affected. Sensorineural hearing loss is usually permanent.
Hearing problems may occur as a late effect of treatments for some childhood cancers, including:
- brain or spinal cord cancers (central nervous system, or CNS, tumours)
- germ cell tumours (a cancer of the reproductive cells)
- neuroblastoma (a cancer of the nervous system)
- osteosarcoma (a type of bone cancer)
- retinoblastoma (a cancer of the retina of the eye)
The risk of developing a hearing problem after treatment for a childhood cancer is related to:
- the child’s age during treatment (children younger than 4 years old at the time of treatment have a greater risk for hearing problems)
- some chemotherapy drugs
- taking other medicines, such as certain antibiotics and diuretics
- receiving radiation to the head
Some chemotherapy drugs, such as cisplatin (Platinol AQ) and carboplatin (Paraplatin, Paraplatin AQ), can damage the cochlea in the inner ear. This damage may cause permanent hearing loss or changes in balance.
Radiation therapy may cause earaches or difficulty hearing if the ear is in the treatment area. Earaches and hearing problems happen if radiation hardens earwax, irritates tissue or swells the Eustachian tube so that fluid builds up in the inner ear. These problems may be temporary and can go away a few months after radiation therapy is finished.
High doses of radiation can cause more permanent hearing problems and hearing loss. These problems may develop if radiation changes the little bones inside the middle ear or causes Eustachian tube dysfunction.
Signs and symptoms of hearing problems include:
- hearing loss
- ringing or tinkling sounds in the ears (called tinnitus)
- difficulty hearing or being easily distracted by background noise
- not paying attention to sounds such as voices or environmental noise
- dizziness or vertigo
- difficulty with language development
- hard, crusty earwax
Tell your doctor or healthcare team if you or your child develops these symptoms after treatment for a childhood cancer.
An audiologist is a health professional who tests for hearing loss and treats people with hearing disorders. An audiologist will monitor a child’s hearing during treatment to diagnose any hearing loss. If hearing loss occurs, the dose of the chemotherapy drug or radiation may be lowered. Children who are treated for cancer will also have follow-up exams to check for hearing loss after treatment is finished.
Hearing loss is usually diagnosed with the following tests.
The audiologist will use an otoscope to do an otoscopic exam of the ear. The otoscope allows the doctor to look at the ear canal and the eardrum to check for signs of infection or hearing loss. Sometimes the doctor will release a puff of air into the ear canal to check if the eardrum moves. The eardrum will move in a healthy ear.
A hearing exam is done before treatment with drugs that may cause hearing problems or radiation to the head. This test provides doctors with a baseline that they can check the child’s hearing against during and after treatment to see if their hearing is affected.
A hearing exam tests the child’s ability to hear different sounds. Sounds vary based on the intensity (volume or loudness) and the pitch (speed of sound vibrations). Many different types of tests can be used to check a child’s hearing. Tests are chosen based on the child’s age and level of understanding.
An audiologist will regularly check a child’s hearing to look for very subtle changes. For example, hearing loss sometimes happens in only one ear or only in the very high pitches.
If the results of the hearing exam are normal, it may be repeated every 2–5 years or if symptoms of hearing loss develop.
Find out more about hearing exam.
Hearing loss can affect a child’s ability to communicate and carry out daily activities. Younger children who have hearing problems are at higher risk for problems with learning, language development and social functioning and for difficulties in school.
If hearing loss develops, the child will be evaluated by an audiologist or otologist. An otologist is a doctor who specializes in hearing disorders.
Depending on the age of the child when hearing loss occurs, speech therapy and special education may be needed to address specific learning needs caused by the hearing loss. Speech and language therapy with a speech-language pathologist helps children overcome hearing problems. This may include the use of hearing aids and other assistive devices.
You can try the following tips to help you communicate with a child who has trouble hearing:
- Get the child’s attention before speaking.
- Use simple sentences.
- Reword something if the child doesn’t understand.
- Use gestures and facial expressions to add meaning to words.
- If one ear has better hearing than the other, approach the child from the side with the good ear.
- Limit background noise or bring the child to a quiet area to talk to them.
- Protect hearing from further damage. For example, limit the child’s exposure to loud sounds like noisy toys or loud music through headphones.
All people who are treated for childhood cancer need regular follow-up. The healthcare team will develop a follow-up plan based on the type of cancer, how it was treated and your needs.
Any childhood cancer survivor treated with chemotherapy that can cause hearing problems, such as cisplatin and carboplatin, or radiation therapy to the ear area should have a yearly physical exam.
The child may continue to have hearing tests on a yearly basis. They may visit a speech-language pathologist following treatment on an outpatient basis as necessary.
Tell your healthcare team if you were treated for childhood cancer. It is important that they know your treatment history.