The V111 cranial nerve is the auditory nerve or vestibulocochlear nerve which carries the sound wave from inner ear to the brain. It is also involved in balancing of the body. This sensory nerve has two branches. The cochlear branch is involved in carrying the sound while the vestibular branch ascertains maintaining proper balance of the body.
Damage to inner nerve thus can affect both the balance and hearing. Several factors such as head trauma, infection, tumor, exposure to loud noise can cause this damage. Since inner ear nerve damage is irreversible, early detection is essential for a better treatment outcome.
Main Causes Of Inner Ear Nerve Damage
There are several factors that can cause damage to the inner nerve. Below are given the causes of inner nerve damage:
- Injury: Injury to the head is one of the major causes of hearing impairment. Especially a closed injury to the temporal bone can damage the auditory nerve. This nerve passes from brain through a grove in the temporal bone towards the inner ear. Further down it divides into two branches, the cochlear and the vestibular. Even a small fracture to the temporal bone can cause affect the nerve functioning.
- Infection: Infection in the middle ear known as otitis media can cause damage to the tiny sensory endings of the auditory nerve called the hair cells. This can lead to hearing loss or compromise with the balance mechanism.
- Loud noise: Long term exposure to loud sounds as in factory setup or rock music can cause damage to the inner nerve of ear. People working in mines, quarries, textile factories, and those who work with machines that produce very high level of sound than the tolerated limit are susceptible to auditory nerve damage.
- Tumors: Brain tumor can compress the branches of auditory nerve and cause hearing loss as well as imbalance. Acoustic neuroma is one such tumor which can lead to ear nerve damage.
- Medications: Certain medications can cause sensotineural damage. This may include strong antibiotics taken for long time or NSAID’s medicines that are used to alleviate pain and inflammation.
Symptoms Of Inner Ear Nerve Damage
The three main symptoms that may be indicative of ear nerve damage are hearing loss, vertigo, vomiting, and tinnitus.
- Hearing loss: Hearing loss can be frustrating and embarrassing for a person. It can lead him to isolation. Permanent hearing loss can occur when there is damage to the sensory nerve ending of the auditory nerve. It does not transmit proper signals the brain. It may be sudden in onset or an ongoing process. People suffering from this condition often complain of people mumbling but they do not understand what is being said. Aging can be one of the reasons aside from injury, viral infections such as chickenpox and mumps.
- Tinnitus: Tinnitus is a sound that a person hears which is not coming from any environmental source. This phantom sound can be heard as constant ringing in the ears, roaring, clicking or buzzing sound. Patient may experience this sound in one ear or both the ears. Tinnitus is subjective meaning that only the person with nerve damage can hear the sound. People around him cannot hear.
- Vertigo: It is an abnormal sense of motion where the patient feels as if the surrounding around him is spinning. However, in actuality it is not moving. In many cases there is associated vomiting and nausea.
Treatment For Inner Ear Nerve Damage
Ear nerve damage in majority of cases is permanent, especially if it is sensory ear nerve damage. However, hearing loss is not complete in majority of cases. If the underlying trigger is detected and corrected, partial hearing can still be preserved. For example if the offending agent is some medication, complete stoppage of the trigger can reverse the damage.
If the cause is benign tumor compressing the nerve, surgical removal of the tumor is helpful to preserve hearing and prevent damage. If the dizziness is due to acoustic neuroma which is caused by viral infection resolution typically occurs within 10 to 12 days.