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If a person’s hearing aid is disturbed, then he is not able to normally perceive the sounds of the world around him. Sensorineural hearing loss is one of the most common causes of hearing loss (about 75% of all cases of hearing loss). The disease leads to damage to the auditory nerve. Often it is not possible to restore hearing.
Anatomy of the auditory nerve
The auditory nerve belongs to the 8th pair of cranial nerves.
Features of the development of sensorineural hearing loss and their relationship with the anatomy of the auditory nerve can be traced in such moments as:
The auditory nerve has a fibrous structure, which is represented by plexuses of nerve fibers. They are unevenly distributed. Along the edge of the trunk are fibers that are responsible for the transmission of low-frequency sounds. Fibers running in the center transmit high-pitched sounds. Therefore, with sensorineural hearing loss, in the first place, a person ceases to distinguish precisely low tones.
Since the vestibular part of the eighth pair of cranial nerves go along with the auditory pair, with the development of sensorineural hearing loss, people often suffer from dizziness, nausea, and poor balance.
In the early stages of the development of pathology, complete deafness is not observed, since the nerve trunk is damaged gradually.
If the auditory nerve suffers from a lack of oxygen for a long time, it begins to die. This will lead to the fact that deafness will be irreversible.
With sensorineural hearing loss, the part of the auditory nerve that is outside the brain is affected. Therefore, a person deafs most often in one ear. Although sometimes the pathological process develops from two sides at once.
Disease classification
Depending on the concentration of the pathological process, the following types of sensorineural hearing loss are distinguished:
Unilateral lesion (observed most often).
Bilateral pathology. It, in turn, can be symmetrical and asymmetric. With a symmetrical lesion, both ears begin to perceive sounds equally poorly. With asymmetric hearing loss, hearing impairment has a different degree of severity.
Depending on the rate of progression of the disease, the following types are distinguished:
Sudden hearing loss that develops within 12 hours. Symptoms may persist for 14-21 days.
Acute hearing loss that develops within 3 days. Its maximum duration is 5 weeks.
Subacute hearing loss that develops in 7-21 days. Symptoms of the disease persist for 1-3 months.
Chronic hearing loss that develops in 1-3 weeks and persists for more than 3 months. Sometimes hearing can never be restored.
Degrees of sensorineural hearing loss
Depending on the frequency of sounds a person can perceive, the degrees of hearing loss differ:
From 25 to 39 dB – 1 degree of hearing loss. A person hears a whisper at a distance of 3 meters, and conversational speech at a distance of 6 meters.
From 40 to 54 dB – 2 degree of hearing loss. He distinguishes a whisper at a distance of a meter, and colloquial speech at a distance of 4 m.
From 55 to 69 dB – 3 degree of hearing loss. A person does not distinguish a whisper at all, and colloquial speech – at a distance of 1 m.
From 70 to 89 dB – 4 degree of hearing loss. A person hears only loud speech if someone shouts directly into his ear.
Above 90 dB – complete deafness. The person does not hear speech at all.
Causes of sensorineural hearing loss
With sensorineural hearing loss, the nerve always receives less nutrition and is pinched by some structures, for example, edematous tissues, a growing tumor, etc.
Such violations may be due to the following reasons:
Transferred infections. Some viruses and microbes can damage the nervous tissue, which leads to irreversible consequences. Therefore, hearing loss can be the result of SARS, herpes, influenza, mumps, meningitis, neurosyphilis.
Vascular pathologies: atherosclerosis, impaired circulation in the vertebrobasilar basin, hypertension, diabetes mellitus. All these diseases lead to the fact that hearing receptors receive less nutrition and oxygen. They gradually begin to lose their function and the person becomes deaf. In addition, microcirculation of blood in the structure of the nerve trunk is disturbed.
Diseases of the spine. These include spondylosis, uncovertebral arthrosis, spondylolisthesis, accompanied by the development of vertebral artery syndrome.
Injuries received: TBI, trauma to the hearing aid due to exposure to loud sounds, barotrauma, which occurs with sudden pressure drops. Most often, it is the receptors of the auditory nerve that are injured, but with strong blows to the temple area, its trunk can be damaged.
Poisoning by chemicals. Alcohol, nicotine, arsenic, mercury, benzene, aniline, hydrogen sulfide, fluorine can damage the auditory nerve and lead to the development of hearing loss. In this regard, drugs such as Streptomycin, Gentamicin, Vancomycin are dangerous. Amikacin, Cisplatin, Endoxan, Quinidine and malaria drugs.
Irradiation of the body. Sensorineural hearing loss rarely develops due to exposure to radiation. This can happen when patients undergo radiation therapy for the treatment of cancerous tumors, as well as when in contact with a radiation source during emergencies. Radiation can destroy any tissue in the human body, but nerves are rarely affected.
Sometimes the cause of sensorineural hearing loss cannot be determined. In this case, they speak of an idiopathic form of the disease.
Symptoms of sensorineural hearing loss
The first symptom of acoustic neuritis is hearing loss. First, a person begins to hear worse low tones, such as bass. As the pathology progresses, the audibility of high-frequency sounds worsens.
About 92% of patients complain of tinnitus, which can occur on one or both sides. The timbre of noise differs, one tone passes into another. In this case, the ears with neuritis of the auditory nerve do not hurt, unless the violation develops due to the injury.
Other symptoms of sensorineural hearing loss include:
Dizziness.
Unsteadiness of gait.
Deterioration of coordination.
Nausea, which may result in vomiting.
Diagnostics
Patients with suspected sensorineural hearing loss are hospitalized. A preliminary diagnosis is made on the basis of the patient’s complaints.
In the conditions of a specialized hospital, he is prescribed a number of examinations:
Speech study of hearing. The doctor stands at a distance of 6 meters from the patient and begins to whisper the words in a low tone, and then with high sounds. If a person does not hear what the doctor is saying, then he begins to come closer to him. Normally, the patient should hear a whisper already at a distance of 6 meters.
Hearing test using a tuning fork. This is an instrument that makes sounds of different frequencies. With the help of a tuning fork, a Rinne test is performed (if hearing deteriorates, the test result will be negative) and a Weber test (a healthy ear will hear sounds better).
Hearing study using the audiometry method. For the test, a device called an audiometer is used. The patient is offered to listen to sounds of different frequencies, and the device will register the tones that he hears. Based on the data obtained, a curve is built that displays the function of hearing. There are several types of audiometry: tone suprathreshold audiometry, the method of auditory sensitivity to ultrasound, speech audiometry.
If a tumor growing in the temporal region is suspected, the patient is referred for computed tomography. Another diagnostic method that specifies the cause is ultrasound of the vessels of the vertebrobasilar basin.
Treatment
Therapy largely determines the form of neuritis of the auditory nerve. Therefore, these areas need to be considered separately.
Treatment of acute form
Patients with this diagnosis are immediately hospitalized. In this case, it is necessary to exclude any factors that damage his hearing, including loud sounds.
Drug therapy is reduced to the appointment of drugs such as:
Hormonal agents and drugs that contribute to the normalization of blood microcirculation. They are administered intravenously, in a hospital setting. The course of treatment is a week.
Vitamin E, ascorbic acid are used in treatment, as they have pronounced antioxidant properties.
If the course of treatment with some remedy should be extended, then it is no longer administered intravenously, but is prescribed for oral administration.
Treatment of chronic and subacute form
To stop the progression of the disease, it is required to implement the following measures:
Creation of a protective auditory mode for the patient.
Treatment of diseases that led to the development of neuritis.
The use of a treatment regimen that is prescribed for an acute form of the disease. With chronic hearing loss, it is practiced 2 times a year.
If hearing loss worsens the quality of human life, then it is advisable to use special devices that allow you to bring it back to normal.
Adaptation of patients with sensorineural hearing loss
Hearing loss is a serious problem. However, there are effective methods that allow such people to adapt in society.
They include:
Hearing aids special devices. Each person can receive such treatment absolutely free of charge if he is diagnosed with 2 or 3 degrees of hearing loss. Hearing aids can be behind the ear or in the ear. With their help, a person begins to hear normally.
Implant middle ear, which can help people with 3 degrees of hearing loss. It is implanted in the event that it is not possible to use an external hearing aid.
cochlear implant. Such a drug is implanted in patients with 4 degrees of hearing loss, provided that other methods of treatment have been ineffective. In addition, a person, at his own request and at his own expense, can go to a private clinic, where he will be operated on. The implant acts like a person’s own ear, transmitting signals to the auditory nerve trunk and then to the brain.
The sooner treatment is started, the more effective it will be. Therefore, when the first signs of hearing loss appear, you should seek medical help.
Answers to popular questions
Is it possible to cope with neuritis of the auditory nerve using traditional medicine methods? No, they are not effective. However, some physiotherapeutic methods, for example, endaural electrophoresis with Dibazol, Nicotinic acid and other drugs, massage, and current treatment, allow speeding up recovery.
Is hearing restored after therapy? In 93% of cases, in patients with acute hearing loss, hearing is restored within the first 30 days from the start of treatment. If the disease has a chronic course, then the prognosis worsens.
What can replace a hearing aid? You can resort to the method of vibrosound stimulation, to pedagogical activation of hearing, to electroreflexotherapy. They allow you to restore the receptors of the damaged nerve, but their effectiveness is lower than when wearing a hearing aid. In addition, these techniques are not widely used in Russia.
Is the disease inherited? Hearing loss can be transmitted with syphilis, with congenital otosclerosis, and with a progressive labyrinth.
How to improve vestibular function in neuritis? It is possible to use nootropic drugs, as well as anticholinesterase agents, for example, Neuromidin.