Hearing Problems in Children

Hearing Problems in Children

Normal hearing is initially needed to understand spoken language and then, later, to produce clear speech.

But many children develop hearing difficulties at birth or during infancy and the toddler years which result in consequences like speech and language difficulty, social and societal problems etc. Hence, if your child experiences hearing loss during infancy and early childhood, it demands immediate attention.

Here is an excerpt from a video interview of Dr K V Sreedhar, Consultant ENT, Head & Neck Surgeon at OMNI Hospitals, Visakhapatnam on ‘Hearing Problems in Children’.

Q. How does an ear work?

A. The ear consists of three main compartments – the outer ear, middle ear and inner ear.

The outer ear comes in all types of shapes and sizes. This structure helps to give each of us our unique appearance. The medical term for the outer ear is the auricle or pinna. The ear canal starts at the outer ear and ends at the eardrum. The canal is approximately an inch in length. The eardrum is about the size of a dime and is the same size in the newborn baby as in the adult. The space inside the eardrum is called the middle ear. The medical term for all three bones together is the middle ear ossicles.

Next to the middle ear in the bone of the skull is a small compartment which contains the hearing and balance apparatus known as the inner ear. The inner ear has two main parts. The cochlea, which is the hearing portion, and the semicircular canals are the balance portion.

The outer ear captures sound waves. The sound travels down the ear canal and hits the eardrum. The eardrum vibrates which causes the ossicles (middle ear bones) to vibrate. A piston action of the ossicles creates a wave in the fluid in the inner ear. The fluid wave stimulates the hair cells in the cochlea and an electrical impulse is sent through the eighth cranial nerve to the brain.

The balance system works by sending continuous electrical impulses to the brain. Moving the head causes the fluid in the semi-circular canals to shift. This, in turn, changes the electrical impulses to the brain. The brain uses this information to make any adjustments the body needs for balance.

Q. What is hearing loss?

A. Hearing loss can be something that happens suddenly if you’re exposed to a loud sound or bang. It can also happen slowly over a long period of time, which is often the case with age-related hearing loss.

Hearing loss means you have lost the ability to hear certain sounds. Maybe you can no longer hear high-pitched tones, like the voices of women or children. Or maybe you can’t pick out a single voice if there is a lot of conversation in the background.

Sometimes hearing loss is temporary, like a ringing in your ears after a noisy concert. Most often, it is permanent because the mechanisms that help you hear have been damaged.

Q. When should hearing ability in children be evaluated?

A. Approximately 2 to 4 of every 1,000 babies are born with some degree of hearing loss, making it one of the most common birth defects.

Hearing problems may be suspected in children who are not responding to sounds or who are not developing their language skills appropriately. It is important to remember that not every child is the same, and children reach milestones at different ages.

Below are some milestones that can be used to evaluate hearing in children:

– Birth to 3 months:

Reacts to loud sounds with a startle reflex
Is soothed and quieted by soft sounds
Turns head to you when you speak

– 3 to 6 months:

Looks or turns toward a new sound
Responds to no and changes in tone of voice
Imitates his/her own voice

– 6 to 10 months:

Responds to his/her own name, telephone ringing, someone’s voice, even when not loud
Knows words for common things (cup, shoe) and sayings (bye-bye)
Makes babbling sounds, even when alone

– 10 to 15 months:

Plays with own voice, enjoying the sound and feel of it
Points to or looks at familiar objects or people when asked to do so
Imitates simple words and sounds; may use a few single words meaningfully

– 15 to 18 months:

Follows simple directions, such as give me the ball without being shown
Uses words he/she has learned often
Uses 2 -3 word sentences to talk about and ask for things

– 18 to 24 months:

Understands simple yes-no questions (Are you hungry?)
Understands simple phrases (in the cup, on the table)
Enjoys being read to

– 24 to 36 months:

Understands not now and no more
Chooses things by size (big, little)
Follows two-step commands

Q. Can a newborn be assessed for hearing loss?

A. Yes, a newborn can and should be evaluated for hearing loss as soon as possible using the below,

– Birth to 3 months:

Reacts to loud sounds with a startle reflex
Is soothed and quieted by soft sounds
Turns head to you when you speak
Is awakened by loud voices and sounds
Smiles in response to voices when spoken to
Seems to know your voice and quiets down if crying

Q. What are the types of hearing loss in children?

A. If your child has been diagnosed with hearing loss, it means that something with your child’s ears, the nerves that come from the ears, or the part of the brain that controls hearing is not working as well as it should.

Hearing loss can range from mild, where only some sounds are not heard, to profound, where nothing is heard. No matter the severity of the hearing loss, it can affect your child’s educational and social development in significant ways.

Types of hearing loss:

Conductive Hearing Loss:

It occurs when sound is blocked or reduced as it travels to the inner ear. This may be due to an obstruction or abnormality of the outer or middle ear. Once sound reaches the inner ear, hearing is within normal limits.

Sensorineural Hearing Loss (SNHL):

It occurs when there is damage to the inner ear (cochlea), or to the nerve pathways from the inner ear to the brain. This is the most common type of permanent hearing loss.

Mixed Hearing Loss:

This is a combination of a conductive hearing loss and sensorineural hearing loss. A mixed hearing loss occurs when sound is unable to be transmitted from the outer or middle ear to the inner ear normally, and there is damage to the inner ear (cochlea) or auditory nerve.

Auditory Neuropathy Spectrum Disorder (ANSD)

This type of hearing loss happens when the cochlea receives the sound, but the auditory nerve carries jumbled electrical signals to the brain (dyssynchrony). This means that instead of a smooth transition of information from the cochlea to the brain, the signals are not timed correctly so information is not relayed to the brain in a consistent manner.

Q. How often should a child’s hearing be tested?

A. A child can be tested for hearing when they are born immediately and then every year until they reach the age of 5.

Q. Does medication cause hearing problems?

A. While medications are taken for their established benefits, all medication has side-effects that you should be aware of before taking. Hearing loss is most commonly associated with six different categories of medications.

The following may be associated with permanent hearing loss:

– Aminoglycoside antibiotics
– Platinum-based chemotherapy

Some medications that are more likely to cause temporary hearing loss:

– Loop diuretics
– Quinine
– Salicylates
– Vinca alkaloids

Q. Is hearing loss hereditary?

A. About 50% of hearing losses present at birth (congenital hearing loss) is caused by genetic factors passed down from one or both parents. In many cases, a child’s hearing loss may exist alongside other conditions as part of a syndrome.

Another 25% of congenital hearing losses occur because of environmental factors during pregnancy or birth. These hearing losses may stem from an infection contracted during pregnancy (such as cytomegalovirus or rubella), a lack of oxygen (anoxia), or issues related to low birth weight and prematurity. Hearing loss may also be caused by life saving medications given to infants in the NICU or from acquired infections, like meningitis.

The remaining 25% of congenital hearing losses are idiopathic, which means the cause is unknown.

Q. What percentage of childhood hearing loss can be prevented?

A. About 25% of childhood hearing loss can be prevented.

Q. What are the treatments for childhood hearing loss?

A. Hearing loss treatment will depend on the child’s symptoms, age, and general health. It will also depend on how severe the condition is.

Managing hearing loss may include 1 or more of the following:

Hearing aids:

Electronic or battery-operated devices that can amplify and change the sound. A microphone receives the sound and changes it into sound waves. The sound waves are then changed into electrical signals.

Cochlear implants:

A surgically placed device that helps to send electrical stimulation to the inner ear. Only children with hearing loss too severe for hearing aid use are candidates for this type of device.

Training in sign language, lip-reading, and other language approaches:

There are many different types of language approaches. These include sign language and lip-reading.

Q. What are hearing aids?

A. Hearing aids are small, battery-powered devices that are worn on the ears to help children with permanent hearing loss hear more clearly. They pick up speech and other sounds through tiny built-in microphones, make them louder, and play them into a child’s ears. Modern hearing aids are “digital.” This means that audiologists use computers to tell the digital chip inside of hearing aids how much loudness to add at different frequencies or pitches.

Hearing aids can improve the ability of a child with hearing loss to speak more clearly, communicate with friends and family, and understand their teachers at school.

Q. What are hearing implants and what are the types?

A. A hearing implant is a hearing device that is typically implanted into the ear. The types of hearing implants are – cochlear implants, bone conduction devices, middle ear implants and brain stem implants.

There are different types of hearing implants. The one which is most relevant for a person with hearing loss depends on the cause and the type of hearing loss. But in all cases, hearing implants are relevant when a person with a hearing loss would not benefit properly from the sound amplification of hearing aids or for some reason is unable to wear hearing aids.

The common types of hearing implants are:

– Cochlear implants (CI):

Cochlear implants (CI) make it possible for people to hear and understand sounds even if they have damaged hair cells in the inner ear and have a severe or a profound hearing loss.

– Bone conduction devices:

Bone conduction devices convert sounds into vibrations that are sent directly into the inner ear via the bones in the head. Bone conduction devices bypass the outer ear and the middle ear. There are active and passive bone conduction devices. With an active device, the skin stays intact.

– Middle ear implants (MEI)

A middle ear implant (MEI) picks up sounds and converts them into vibrations which are sent to the middle ear and further into the inner ear.

– Auditory brainstem implants (ABI)

An auditory brainstem implant (ABI) is an implant that converts sounds into signals that are sent directly to the brain, bypassing the non-functioning or non-existent auditory nerve.

Q. What are some precautions that can be taken to avoid hearing problems in children?

A. Some of the simple things you can do to help stop loud noises from permanently damaging your child’s hearing are:

– Avoid loud noises
– Protect hearing during loud events and activities
– Get hearing tests done once in a year