Can CMV cause hearing loss?


When your baby isn’t feeling well or has a health problem, it can be very scary. Sometimes these health issues can be related to conditions that developed before birth.

A very common virus that a baby can get in the womb is cytomegalovirus (CMV). When a baby gets CMV before birth, it is called congenital CMV.

According to Centers for Disease Control and Prevention (CDC), congenital CMV is the leading infectious cause of sensorineural hearing loss in children. Nearly 1 in 200 babies are born with congenital CMV. Of these, 1 in 5 has lasting health effects, including hearing loss.

Some babies born with congenital CMV who suffer from hearing loss may be born with the hearing loss, while others may have developed it during childhood.

Read on to learn more about CMV and sensorineural hearing loss in children.

Sensorineural hearing loss is the most common type of permanent hearing loss, according to the American Speech-Language-Hearing Association.

This type of hearing loss occurs when the inner ear does not develop properly or is injured.

The ear is made up of three main parts: the outer ear, the middle ear and the inner ear. If a child has congenital CMV, it can affect the development of the inner ear, leading to sensorineural hearing loss.

The inner ear includes a structure called the cochlea which is filled with fluid and has microscopic hairs. When sound waves enter the inner ear, they vibrate the fluid in the cochlea. This vibration moves the tiny hairs in the cochlea and converts sound into electrical signals. These signals are then sent through the nerves to the brain for you to hear the sound.

If part of the inner ear fails to develop or is damaged, sound signals cannot reach the brain, resulting in hearing loss.

Signs of sensorineural hearing loss can vary depending on the age of the child and the severity of the hearing loss.

According to CDCsigns of hearing loss in a baby include:

  • does not have a startle reaction when loud noises occur
  • does not turn around to face a sound after 6 months
  • does not say a single word at 1 year old
  • may seem to hear one sound but not another
  • turn their heads when they see you but not when you call them

Signs of hearing loss in children include:

  • has delayed or unclear speech
  • often ask people to repeat what they said
  • listens to TV or music at a high volume
  • can’t keep up with simple requests

CMV is a form of Herpesviridaevirus. It is a very common infection and individuals can contract it at any time. Many people have no symptoms or effects of CMV.

If a person first contracts CMV during pregnancy, it can be passed to the baby through the placenta. When a baby catches CMV in the womb, it is called congenital CMV.

CMV can cause hearing loss; however, not all babies or children who receive CMV will have hearing loss. Many babies and children with CMV will have mild symptoms or no symptoms.

Although many people with CMV have no symptoms, CMV is still the primary cause non-hereditary hearing loss.

Babies usually have a newborn hearing assessment while they are in the hospital after birth. If this screening shows signs of hearing loss, the baby will be checked again and should have additional tests as they get older.

Children who access health care as they get older will also have routine hearing screenings during annual physical exams with their pediatrician. The American Academy of Pediatrics recommends that all children have a more extensive hearing screening at ages 4, 5, 6, 8, and 10. Children with signs of hearing loss need more frequent screening.

A hearing evaluation for an infant or child with hearing loss due to CMV may include these tests:

Auditory Automated Brainstem Response (AABR)

This test uses a computer, electrodes attached to your child’s head, and a wand or headphones that emit sound into your child’s ear. The AABR test measures markers or responses that your child’s brain does or does not make to these sounds.

Otoacoustic emissions (OAE)

This test is used for children who cannot respond, so it is given to babies and very young children. The OAE test uses small headphones inserted into the ear. Clicking sounds are sent to the ear.

When sounds reach the cochlea, if they vibrate the tiny hairs, very faint sounds called otoacoustic emissions will bounce back to the middle ear. There, the earpiece will measure them.

A hearing assessment for a child may include the AABR, OAE and other tests such as:

Behavioral audiological assessment

This test measures how a child reacts to sounds at different levels. It usually takes place in a soundproof booth or room, and a child will look towards a sound or be prompted to respond when they hear a sound.


This test uses a puff of air delivered into the ear to move the eardrum while a machine records the movements. Because the child must sit still for this test, it is not usually given to very young children.

Tuning fork tests

Tuning fork tests literally use a tuning fork to help determine if there is hearing loss and if the hearing loss is sensorineural. There are two tuning fork tests:

  • Weber’s test. In this test, a tuning fork is struck and placed in the middle of the child’s forehead. If the sound is louder in one ear that does not have hearing loss, the hearing loss in the other ear is likely sensorineural hearing loss.
  • Rinné’s test. This test is primarily used to identify conductive hearing loss. In this test, the tuning fork is struck and placed against the bone behind the ear until the sound stops, then the tuning fork is moved in front of the ear canal. If sound is heard or louder in front of the ear, the hearing loss is likely sensorineural. If sound is heard longer over bone, the cause of hearing loss is likely conductive.

Although there is no cure for sensorineural hearing loss, some children diagnosed with congenital CMV at birth may benefit from antiviral medications. This, according to the CDCmay help reduce the severity of sensorineural hearing loss caused by CMV.

Some options may help children with sensorineural hearing loss, including:

Cochlear implants

Cochlear implants are devices that send signals to the cochlear nerve and help restore the perception of sound and speech in people with sensorineural hearing loss. The device consists of two parts:

  • a receiver, called an electrical network, which is implanted inside the inner ear
  • a microphone or transmitter worn behind the ear

Children born with sensorineural hearing loss can have a cochlear implant when they are very young – between 6 months and 1 year sometimes.

Hearing aids

Hearing aids are devices that help make sounds louder or change sounds so they can be heard by some children with sensorineural hearing loss. There are several types of hearing aids, but most are worn on the ear.

Bone Conduction Hearing Aids

These devices, sometimes called bone-anchored hearing aids (BAHAs), can be used to help children with certain types of sensorineural hearing loss. They send sound through the bone to the middle and inner ear. They can be surgically implanted, magnetic or worn as an outer wrap.

Other therapies

In addition to devices to help improve hearing, children with sensorineural hearing loss can benefit from services and training to help improve their communication skills, such as:

It is important that children with hearing loss receive services as early as possible to ensure that they develop good social and communication skills.

Some children with congenital CMV may have hearing loss at birth, while others may develop it later in childhood or later in life.

Children with congenital CMV may benefit from antiviral medications. For some children, antiviral drugs can help reduce the level of sensorineural hearing loss they have, according to the CDC.

Sensorineural hearing loss is permanent, but some devices can help improve hearing.

Congenital CMV is the leading cause of non-hereditary sensorineural hearing loss in infants. Children with CMV are at risk for hearing loss at birth or as they age. They should have routine hearing tests throughout their lives.

Sensorineural hearing loss cannot be cured, but options such as hearing aids, cochlear implants, and others can help improve hearing. Children with sensorineural hearing loss will also benefit from therapies to help improve their communication and social skills.


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