Essentially, the auditory nerve is responsible for sending vibrations (sound signals) to the brain. Keep in mind; the auditory nerve is by far not the only part of the ear that enables us to hear sounds. Various other ear parts also play a role. They all work together to facilitate this complex hearing process and send the vibrations to the brain for processing.

What is the auditory system?

The auditory system - one of the major body systems - is responsible for the sense of hearing. The hearing system is composed of several different parts and sections. For successful hearing to occur, all of these components have to function correctly.

Here are the components of the auditory system: 

Peripheral auditory system

Outer ear - pinna, ear canal
The pinna, the only visible part of the ear, has a unique spiral shape. It is the first part of the outer ear's anatomy that reacts to sound. The pinna's function is to act as a funnel and direct sound deeper into the ear. As the sound vibrations enter through the pinna, the opening connecting to the ear canal amplifies them, making the sound easier to hear. 
Middle ear - eardrum, hammer, anvil, and stirrup
Seemingly, the eardrum has little to do with hearing, but it actually participates in the hearing process. Although the eardrum's primary role is to act as a shield - to protect the middle and the inner ear - it also serves as a soundboard inside the ear canal. Every time vibration reaches the eardrum, three tiny bones behind it vibrate. These tiny bones are often called hammer, anvil, and stirrup. Every time sound enters the inner ear, these bones vibrate one after another. 
Inner ear - cochlea, organ of corti, auditory nerve
(more about the inner ear below)

Central auditory system

The auditory nerves run from the cochlear nucleus to the nucleus in the brainstem. From there, the neural impulses proceed to the temporal lobe, where the primary auditory cortex is located.

How does the auditory nerve work?

The auditory nerve, located in the inner ear, behind the cochlea, connects to the semi-circular canals and vestibular organ. The cochlea is a small snail-shaped bone structure in the inner ear that, together with some other components, makes up fifty percent of the system that controls hearing. 

The cochlea is where the transformation of sensory information takes place from waveform into the neural form. The cochlear duct contains the organ of Corti. When you hear sound, the cochlea (a fluid-filled sac) begins to vibrate.
Then, the basal membrane part of the cochlea passes the vibration to the auditory nerve through the organ of corti. This organ is a bunch of cells that are referred to as hair. The inner hair cells of the organ of corti are specialized sensory cells that transmit information about sounds through the nervous system to the brain and turn the vibrations into electric neural signals. 

Behind the vestibule, there are three semi-circular, bony canals inside the inner ear. Interestingly, each canal makes a ninety-degree angle with the other canal. Inside each semi-circular canal are the corresponding semi-circular ducts of the membranous labyrinth. 

As you can see, the auditory nerve is not the only part of the ear that helps us hear. The hearing process allows us to hear, differentiate high-frequency and low-frequency sounds, determine the sound's volume and the direction the sound is coming from. 

Damage to the auditory nerve

If your auditory nerve becomes damaged, it can have severe consequences, including permanent hearing loss. The term "neural hearing loss" refers to hearing loss brought on by a damaged auditory nerve, and either diseases or medical conditions can cause it. 
To prevent losing your hearing due to an illness, the key is early detection. Thankfully, your hearing can likely be restored - either fully or partially - depending on the degree of damage to the nerve. 

How do doctors diagnose auditory nerve dysfunction?

If you have suffered hearing loss, it is critical to get your ears examined by a hearing professional. While hearing loss can have multiple causes, your doctor can run some tests to see if auditory nerve damage is at the root of your symptoms.
Auditory neuropathy (AN) or auditory neuropathy spectrum disorder (ANSD) describes a condition that consists of a clear group of auditory irregularities. Your diagnosis may be auditory neuropathy if you have a normal cochlear function but no auditory brainstem response. This is typically the case when the inner ear successfully detects sound but has difficulty sending sound from the ear to the brain. To diagnose this condition, doctors generally find abnormally functioning vestibulocochlear nerve with normally working outer hair cells.
AN can affect people of all ages. Although it is unknown how many people are impacted by this condition, experts believe it plays an important role in many deafness and hearing impairment cases.  

The vestibulocochlear nerve, or the eighth cranial nerve, consists of the vestibular nerve and cochlear nerve. Besides hearing loss, people suffering from auditory neuropathy may also demonstrate vestibular neuropathy.

What causes auditory neuropathy?

Multiple factors can cause auditory neuropathy. One such cause is damaged inner hair cells. Another possible cause is damage to the auditory neurons that transmit sound information to the brain. Other contributing factors may be genetic mutations or damage to the auditory system. 

Finally, some people with auditory neuropathy have neurological diseases that cause issues outside of the hearing system. Examples of such disorders are Charcot-Marie-Tooth syndrome and Friedreich's ataxia.
The information contained in this article is for educational and informational purposes only. You should not use the information as a substitute for, nor should it replace, professional medical advice. If you have any questions about your health, you should always consult with a physician or other health-care professional.