Can damaged ear nerves be restored?

The auditory nerve is composed of the cochlear nerve and the vestibular nerve, which pass through the internal auditory canal to the inner ear, so they can often be damaged at the same time, manifesting as symptoms of both hearing and balance. Although the two are two different components of the same nerve, their responses to the cause of the disease are not quite consistent.

Hearing aids are used to amplify sound to help people with conductive or sensorineural hearing loss, especially those with hearing loss in normal speech frequencies. Hearing aids can also help patients with mainly high-frequency hearing loss or hearing loss in one ear. Hearing aids use microphones to collect sound, amplifiers to increase the volume, and speakers to transmit the amplified sound. Patients with severe hearing loss who still cannot hear sounds even with hearing aids can undergo cochlear implant surgery. The implant consists of an electrode inserted into the cochlea and an internal driver placed in the skull, connected to an external driver, a speech processor, and a microphone. The microphone collects sound waves, and the processor converts the sound waves into electrical impulses, which are transmitted to the internal driver through the external driver and then to the electrode. The electrode current stimulates the auditory nerve.

Cochlear implants do not convert sounds like a normal cochlea, and have different degrees of effect on different patients. They can help some patients lip read, some patients distinguish certain words, and some patients listen to the phone. Cochlear implants can also help deaf people hear and distinguish environmental sounds and alarm signals, such as doorbells, telephones, and alarm clocks. Cochlear implants are more effective for people whose hearing loss has occurred recently or who have used hearing aids successfully.

Damage to the auditory nerve

Noise can damage the auditory nerve

The pathway of sound conduction is as follows: sound signals pass through the external auditory canal - eardrum vibration - auditory ossicles (malleus, stapes, incus) - inner ear fluid vibration - cochlear hair cells produce electrical impulses - auditory nerve - central sound receptors in the brain, and then we hear the sound. If there is a problem in any part of this process, no sound may be heard. In the past, industrial noise was the main factor affecting hearing, but with the invention of the Walkman, music has become the culprit causing damage to the auditory nerve. Exposing music for a long time and at a high volume can damage hearing by damaging the hair cells, auditory nerve fibers, auditory neurons in the inner ear and causing spasm of the microvessels in the inner ear.

There are two main types of damage to hearing caused by sound: one is sudden loud noise, such as setting off firecrackers; the other is chronic noise, which occurs when working under high noise for a long time and the hearing is damaged unknowingly.

pressure

Stress is likely to cause sudden deafness, a type of sensorineural hearing loss, which is characterized by a sudden loss of hearing in one ear, and may be accompanied by tinnitus, a feeling of stuffiness in the ear, etc. Pathogenesis: Stress, fatigue, emotional excitement, viral infection and other factors lead to increased secretion of adrenaline in the body, spasm and contraction of small arteries in the inner ear microcirculation, leading to ischemia and hypoxia of the inner ear, causing inner ear lesions, damage to the sound-sensing part of the inner ear, and hearing loss.

drug

Commonly used antibiotics that can damage the auditory nerve include streptomycin, dihydrostreptomycin, gentamicin, kanamycin, puromycin, neomycin, vancomycin, tobramycin, and kasugamycin. Some other commonly used drugs can also damage the auditory nerve and cause deafness, such as aspirin, furosemide, propranolol, uric acid, quinidine and anticonvulsants. If these drugs are used in combination, the incidence of adverse drug reactions will increase due to drug interactions.

disease

Otitis media, acoustic neuroma, otosclerosis, etc. are all diseases that may directly cause hearing loss. Through early treatment, most people can avoid deafness. Causes of cochlear nerve damage: Common causes include neuritis, meningitis, trauma, poisoning, tumors, arteriosclerosis, certain genetic diseases, and middle ear and inner ear diseases. Causes of vestibular nerve damage: poisoning, blood circulation disorders (basilar artery sclerosis, hypertension, etc.), neuritis, tumors, trauma, demyelinating disease, inner ear disease, etc. Due to different causes, the pathogenesis is also different, which may be demyelination, inflammatory cell infiltration, cell degeneration and compression.

Genetics

50% of deafness is hereditary, which means congenital auditory nerve damage and has a genetic basis. Some children are born with the ability to hear and later lose their hearing. Cochlear implant technology can convert external sounds into electronic sound signals that directly act on the auditory nerve. Through training, children can speak and live like normal children.