Parents who are told that their child is deaf or hard of hearing can display a wide range of emotions and reactions. One of the first steps in understanding hearing loss is to understand how we hear, the types of hearing loss, and what we hear. It is also helpful to explore how hearing changes and milestones to watch for as children grow.
Note: This page includes contributions from both the babyhearing.org and ta team that originally created a site on 'raising deaf kids' (see
How We Hear
Sounds are all around us.
We hear when these sounds pass through the outer, middle and inner parts of our ears, sending thousands of tiny vibrations up to our brain for interpretation.
First sound travels through the outer ear canal and makes the eardrum move. When the eardrum moves, the three middle ear bones vibrate. This vibration creates movement of fluid in the inner ear also known as the cochlea.
The fluid movement causes sensory receptors in the coiled shaped cochlea, to send a signal along the auditory nerve to the brain—and this is how we hear.
Hearing loss may be located in the outer, middle and/or inner ear. There are 3 types of hearing loss:
Conductive hearing loss is caused by a problem in the outer or middle ear resulting in sound being unable to travel to the inner ear properly. Many instances of conductive hearing loss can be treated with medicine or surgery. Causes of conductive hearing loss can include wax in the ear canal, fluid in the middle ear or a hole in the eardrum.
Sensorineural hearing loss is caused by a problem in the inner ear. Sensorineural hearing loss usually cannot be cured with medicine or surgery, but hearing aids or cochlear implants can help in most cases. In young children, sensorineural hearing loss can occur due to:
Mixed hearing loss is a combination of conductive and sensorineural hearing loss. An example of mixed hearing loss is when children with sensorineural hearing loss also have middle ear problems (such as fluid in the middle ear). This can make hearing loss worse.
Unilateral hearing loss is when hearing loss is only in 1 ear.
Progressive hearing loss is when the hearing loss gets worse over time.
Fluctuating hearing loss is when the hearing loss changes. It may sometimes be worse and sometimes better.
People with hearing in the average range can hear from about 0 dB to 140 dB. Here's how loud those sounds can be:
People with hearing in the average range can hear sounds as low as 20 Hz. Some can hear as high as 20,000 Hz. Here's how high or low those sounds can be:
Interact with the Listen Up! infographic below to hear how noisy different sounds are in our environment:https://www.nidcd.nih.gov/health/listen-infographic
The timelines below show the ages at which most hearing babies have developed these skills.Just remember, all children are different. They may not do all of these things on time. If you think your child has a hearing loss, talk to your doctor.
Your child can hear things even before she's born.
A child's hearing changes a lot until 4 to 8 years old.Based on the typical growth for the following age ranges, your child may:
From birth to 3 months:
From 3 to 6 months:
From 6 to 12 months:
By 12 months:
From 12 to 18 months:
By 18 months:
By 2 years:
By 2 ½ years:
By 3 years:
To learn more about how your baby's speech, language, and hearing changes with age, visit the links below to find useful handouts from www.boystownresearchhospital.org. If you have concerns that your child is not meeting these milestones, talk to your child's physician about scheduling a hearing evaluation with a pediatric audiologist.