Auditory perception disorder is expressed in a decrease in the ability of the hearing organs to detect, recognize and perceive speech. Hearing loss (ICD code 10 H90) refers to partial hearing loss, while complete loss of the ability to hear is called deafness.
Loss of their functions by the organs of hearing can develop under the influence of both endogenous and exogenous factors. However, in the end, such a process leads to a violation of auditory perception, when a person cannot hear and distinguish speech. Hearing impairment hinders communication and significantly impairs a person's quality of life.
Diagnostic method
Cerebral evoked potentials are a modern way of testing the performance and functioning of various analyzers, including auditory ones in the cerebral cortex. This diagnostic method makes it possible to record the responses of auditory analyzers to the impact of externalartificially created stimuli.
How is fixation done?
The process of fixing auditory evoked potentials occurs by means of microelectrodes that are brought directly to the nerve endings of a certain area of the cerebral cortex. The size and diameter of microelectrodes do not exceed one micron, which explains their name. The devices are straight rods consisting of high-resistance insulated wire with a sharp recorder end. The microelectrode is fixed and connected to the received signal amplifier. The received information is displayed on the monitor screen and reflected in the data on the magnetic tape.
Non-invasive method
The described method belongs to the category of invasive. However, there is also a non-invasive method for obtaining auditory evoked potentials. In this case, the electrodes are not passed through the cells of the cerebral cortex, but are attached to the neck, knees, torso and scalp.
Classification of responses
Diagnosis through auditory evoked potentials allows you to study the work of the sensory systems of the brain, as well as mental processes. The responses received in response to the impact of an artificial stimulus are usually classified depending on the speed of their receipt into:
- Short latency - up to 50 milliseconds.
- Medium latent - 50-100 milliseconds.
- Long latency - over 100 milliseconds.
Acoustic auditory evoked potentials result from stimulation of the auditory cortexsound clicks occurring alternately. Sound is delivered first to the patient's left ear and then to the right. The speed of receiving the signal is reflected on a special monitor, on the basis of which the decoding of the received indicators is carried out.
Auditory and visual potentials allow diagnosis and confirmation of damage to the optic nerves and tracts, as well as lesions of the hearing organs, both central and peripheral.
Often the method is used to test hearing in children as the most reliable in identifying a pathological process.
Tinnitus as a sign of hearing impairment
Many wonder why tinnitus and what to do.
This common symptom, also called tinnitus, is not an independent pathology, but only indicates the presence of diseases of the acoustic system or hearing organs. Experts believe that tinnitus may be a sign of the following diseases:
- Hypertension or hypotension.
- Osteochondrosis, localized in the cervical region.
- Inflammatory process in the ear, including otitis.
- Hearing loss (ICD code 10 H90) of sensorineural type.
- Ménière's disease.
- Vascular atherosclerosis.
- State of stress.
- Pathologies of the thyroid gland, diabetes mellitus and other diseases of the endocrine system.
- Multiple sclerosis.
- Using certain medications, including diuretics, Aspirin, antibiotics, tricyclic antidepressants, etc.
- Acoustic injury.
Whybuzzing in the ears and what to do, it is important to find out in a timely manner.
Most diseases can be diagnosed by evoked potentials. It is necessary to identify the cause of tinnitus, since the treatment and the effectiveness of the therapeutic measures taken will depend on this. Among the causes leading to the appearance of tinnitus, a special place is occupied by acoustic neuroma, the symptoms and treatment of which we will consider in detail below.
Neuroma: Description
The disease is a neoplasm of a benign type. The diagnosis of "acoustic neuroma" is made in every tenth case of the appearance of tumors in the brain. The neoplasm is not prone to malignancy and metastasis and, in general, is not dangerous to human life. Not in all cases, the decision is made to surgically remove the tumor. If it stops progressing and growing, the choice is made in favor of waiting tactics.
The causes of acoustic neuroma are well understood. Most often, along with neurinoma, type 2 neurofibromatosis is fixed, when a patient regularly and inexplicably develops benign tumors in the nervous system. By the end of life, this pathology provokes a complete loss of vision and hearing.
Most often, neurinoma occurs in the fair sex. There are no preventive measures for this disease, the patient is required to be attentive to their own he alth and consult a doctor at the first sign of hearing loss.
Stages
Neurinoma develops in stages, like any tumor neoplasm. Pathology goes through the following stages:
- The first is characterized by the size of the tumor, not exceeding two centimeters. The disease passes in a latent form and can be manifested by motion sickness in transport, as well as dizziness of unknown origin.
- The second stage is accompanied by tumor growth up to three centimeters and the first pronounced signs of the disease, the patient experiences asynchrony of movements, facial distortion, a sharp decrease in speech perception by ear, and visual impairment.
- The third stage is registered when the tumor reaches a size of more than four centimeters. It becomes difficult for the patient to move evenly, there is strabismus and impaired auditory and visual function.
Symptoms of neuroma
Signs of neurinoma appear in stages, depending on the progress of the growth of the tumor and the stage of its development. The most characteristic symptoms of an acoustic nerve tumor are:
- Decrease in the quality of auditory perception. This is the first and very important symptom of the disease. Hearing impairment is mild and not always noticed by the patient. A person may complain of a hum and noise in the ears, which is a reaction of the cochlea and auditory nerve to squeezing them with a growing tumor.
- Dizziness. Most often, it is noted simultaneously with a decrease in auditory perception. This is due to the pressure of the neoplasm not only on the nerve responsiblefor hearing, but also for the one that is responsible for the vestibular apparatus. After dizziness, a vestibular crisis may follow, accompanied by nausea and vomiting, pain in the head, chaotic horizontal eye movements, which are already detected during diagnostic measures.
- Soreness and parasthesia. At the initial stage of the development of neuroma, the patient feels numbness of a part of the face, as well as goosebumps and tingling, reminiscent of the situation after a long stay in a static position. After that, a pain syndrome is manifested, characterized by dull and aching pains, which can be taken by the patient for dental or caused by neuralgic disorders. The pain syndrome eventually takes on a permanent character and radiates to the occipital region, in the direction on which the neurinoma was detected.
- Paresis. Occurs when squeezing an overgrown neurinoma of the facial nerve. With paresis, the affected area slows down movement, a person expresses emotions with effort, in some cases the symptom is accompanied by paralysis. In addition, part of the tongue loses sensation, resulting in increased salivation.
- Weakness of the muscles responsible for the process of chewing food. Manifested simultaneously with paresis. In some cases, complete atrophy of the masticatory muscles occurs.
Symptoms and treatment of acoustic neuroma are interrelated.
Further symptoms depend on the direction in which the neuroma grows. If the tumor grows back and up, the cerebellum is compressed. In this case, it becomes difficult for the patient to move smoothly, it is difficult to maintain one positionfor a long time and keep the balance. When the neuroma grows back and down, the vagus and glossopharyngeal nerves are compressed. This leads to difficulty in pronouncing sounds, swallowing, loss of sensation in the back of the tongue. In some cases, the speech function is completely lost, the affected area of the tongue atrophies.
At the last stage of damage to the auditory nerve, intracranial pressure increases, which causes visual impairment, blind spots appear in several areas. In addition, there is vomiting of unknown origin, pain in the head, concentrated in the occipital or frontal part of the head. Painkillers usually don't do the trick.
Therapy
Timely treatment will prevent the consequences of neurinoma. Therapy in the later stages may be accompanied by complications in the form of damage to the facial nerve, hearing or paralysis of facial muscles.
Where to buy a hearing aid? This is a common question. More on that later.
Treatment of neuroma is carried out by several methods that can be combined or interchanged in the absence of the effect of therapy.
Expectant tactics
If the acoustic neuroma does not show a tendency to grow and was discovered by chance, the decision to surgically remove it is not made. The specialist prescribes regular visits and examinations several times a year. If the tumor has not grown in two years, the examination beginscarried out every year or when signs of neoplasm progress are detected. In addition, expectant management is chosen in the case of an elderly patient, since the operation in this case is life-threatening. Even in the case of slow tumor growth, the specialist often decides to wait. To reduce the intensity of symptoms, the patient is prescribed painkillers and anti-inflammatory drugs, as well as diuretics to relieve swelling.
Radiation therapy
It is prescribed in case of contraindications for surgical intervention or when the neuroma is small and can be destroyed by radiation. The procedures are carried out in a course, and even if the neoplasm is not completely destroyed, it may decrease and stop growing.
Surgical removal of this pathological tumor
If, after irradiation, the tumor began to increase in size, and the patient's body allows the operation, doctors decide on the surgical removal of the neuroma. The procedure is performed under general anesthesia. In the future, antibiotics are prescribed to prevent infectious complications.
General recovery after tumor removal can be up to one year. The patient will stay in the hospital for at least two weeks after the operation. In some cases, a recurrence of a neuroma is not excluded, when tumor cells remain in the patient's body.
Hearing aid
If hearing is permanently lost or there is a partial impairment of speech perception, the patient may be advised to wear a hearing aid. Where to buy it? The device is made to order in specialized clinics or stores, taking into account the diagnosis and the degree of hearing loss.
In childhood, it is very important to diagnose hearing impairment in time, as timely detection will help to avoid complications in the child's later life. Today, there are quite a few modern and non-invasive methods for detecting auditory disorders, which are widely used in medical practice.
We looked at what evoked potentials are.
