The Four Types of Hearing Loss
A person’s auditory system consists of the outer ear, middle ear, inner ear and acoustic nerve. When one of these parts is not working in an optimal way, a hearing loss can occur. While hearing loss can range from mild to profound, there are four classifications that all hearing losses fall under.
The four types of hearing loss are sensorineural, conductive, mixed (sensorineural and conductive) and auditory neuropathy spectrum disorder (ANSD). While most children at CCHAT have sensorineural hearing loss, CCHAT sees students with all four types and is equipped to provide service for each of these children.
Sensorineural Hearing Loss
In a sensorineural hearing loss, a person is having issues in the inner ear (cochlea) or acoustic nerve. Damage to these structures can occur due to exposure to loud noises, illness (meningitis), ototoxic medications, or it can happen simply due to genetics or the aging process.
Sensorineural hearing loss is permanent, and treatments include the use of hearing aids and cochlear implants.
Conductive Hearing Loss
A conductive hearing loss occurs when something prevents sound from passing through the outer or middle ear and into the inner ear. This can occur when earwax or fluid builds up in the ear canal, or when there is damage to the eardrum or bones in the middle ear (ossicles). There may also be a birth defect that prevents sound waves from entering the ear to stimulate the acoustic nerve, such as atresia or microtia.
A person dealing with conductive hearing loss has multiple options for treatment, depending on the specific issue. Treatments may include surgery to repair structural abnormalities, a procedure to remove blockages, or the implementation of a hearing aid, cochlear implant or bone-anchored hearing aid (BAHA).
Mixed Hearing Loss
In some cases, a person may be suffering from both a sensorineural and conductive hearing loss. In this instance, the issue is classified as a mixed hearing loss. Mixed hearing loss affects both the inner ear and outer or middle ear, and as such, it can lead to a more profound hearing loss.
Treatments will vary depending on the severity of the hearing loss, but in addition to a surgical procedure, hearing aids and cochlear implants may be necessary.
Auditory Neuropathy Spectrum Disorder
Sometimes sound is able to enter an ear normally and reach the acoustic nerve, but there is a problem when the sound is transmitted to the brain. This hearing loss is known as auditory neuropathy spectrum disorder (ANSD).
ANSD can occur for a variety of reasons. In some cases, the hair cells of the inner ear are damaged and are unable to properly transmit sound information to the brain. Sometimes a genetic mutation is the cause of this hearing loss, and other times damage that occurs to the auditory nerve can lead to ANSD.
People with ANSD may seem to have normal hearing sensitivity on a hearing test, but they may struggle to understand spoken words. In some cases, a hearing aid or cochlear implant paired with a hearing-assistive technology (HAT) system can help mitigate the negative effects of this hearing loss. However, more severe cases, in which the person has great difficulty understanding speech, may require the use of a visual communication technique, like sign language or a picture exchange communication system (PECS).
Talk to Your Audiologist
If you suspect your child may be dealing with hearing loss, it is important to consult your audiologist as soon as possible. Your audiologist will be able to diagnose the type of hearing loss and recommend the proper form of treatment. Many hearing loss cases can be treated, and the sooner you receive a professional diagnosis, the earlier you can begin a path to communication that works best for your child.
To learn more about the hearing tests and audiology services that CCHAT can provide, visit our Hearing Tests for Children page.