Understanding the Four Types of Hearing Loss: Causes, Treatments, and Solutions

What is Hearing Loss? Understanding the Auditory System

A person’s auditory system consists of the outer ear, middle ear, inner ear, and acoustic nerve. When one of these parts is not functioning optimally, a hearing loss can occur. While hearing loss can range from mild to profound, there are four classifications that all hearing losses fall under, and each may have a different cause.

The Four Types of Hearing Loss Explained

The four primary types of hearing loss are sensorineural, conductive, mixed (a combination of sensorineural and conductive), and auditory neuropathy spectrum disorder (ANSD). While most children at CCHAT have sensorineural hearing loss, CCHAT serves students with all four types and is equipped to provide services tailored to each of these children. 

Sensorineural Hearing Loss: Causes and Treatment Options

Factors Leading to Inner Ear and Nerve Damage

In a sensorineural hearing loss, a person has issues in the inner ear (cochlea) or the acoustic nerve. Damage to these structures can occur due to exposure to loud noises, illness (such as 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: Understanding the Blockages

Common Causes and Available Treatments for Outer and Middle Ear Issues

A conductive hearing impairment 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: Combining Sensorineural and Conductive Factors

How Dual Hearing Loss Impacts Treatment Approaches

In some cases, a person may be experiencing both 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; in addition to a surgical procedure, hearing aids and cochlear implants may also be necessary. 

Auditory Neuropathy Spectrum Disorder: A Unique Hearing Challenge 

Causes and Strategies for Managing ANSD

Sometimes sound can 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 various 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 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-assistie 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). 

When to Consult an Audiologist: Importance of Early Diagnosis

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.