Doppler ultrasound of extracranial vessels- study of the condition of the carotid and vertebral arteries. Provides information important for diagnosis and treatment in case of cerebrovascular insufficiency, various types of headaches, dizziness (especially associated with turning the head) or instability when walking, attacks of falls and/or loss of consciousness.

Transcranial Doppler ultrasound- a method for studying blood flow in the vessels of the brain. Used in diagnosing the condition of cerebral vessels, the presence of vascular anomalies, impaired outflow of venous blood from the cranial cavity, identifying indirect signs of increased intracranial pressure

Doppler ultrasound of peripheral vessels- study of blood flow in the peripheral vessels of the arms and legs. The study is informative for complaints of pain in the extremities during exercise and lameness, chilliness in the arms and legs, changes in the color of the skin of the arms and legs. Helps in the diagnosis of obliterating diseases of the vessels of the extremities, venous pathology (varicose and post-thrombophlebitis diseases, incompetence of venous valves).

Ultrasound Dopplerography of the ocular vessels- allows you to assess the degree and nature of blood flow disturbance in the fundus during blockage of the arteries of the eye, with hypertension, with diabetes mellitus.

Ultrasound diagnosis of vascular diseases using duplex scanning is a fast, highly informative, absolutely safe, non-invasive research method. Duplex scanning is a method that combines the capabilities of visualizing vascular structures in real time with the characteristics of blood flow in a given vessel under study. This technology in some cases can exceed the accuracy of X-ray contrast angiography.

DS most widely used in the diagnosis of diseases of the branches of the aortic arch and peripheral vessels. Using the method, you can evaluate the condition of the vascular walls, their thickness, narrowing and degree of narrowing of the vessel, the presence of inclusions in the lumen, such as a blood clot, atherosclerotic plaque. The most common cause of narrowing of the carotid arteries is atherosclerosis, less often - inflammatory diseases; Congenital anomalies of vascular development are also possible. Of great importance for the prognosis of atherosclerotic lesions of cerebral vessels and the choice of treatment is the determination of the structure of the atherosclerotic plaque - whether it is relatively “stable”, dense or unfavorable, “soft”, which is a source of embolism.

DS allows you to assess the blood circulation of the lower extremities, the sufficiency of blood inflow and venous outflow, the condition of the valvular apparatus of the veins, the presence of varicose veins, thrombophlebitis, the condition of the compensation system, etc.

Echo-encephalography- a method of studying the brain using ultrasound. The study allows us to determine gross displacements of the midline structures of the brain, expansion of the cerebral ventricles, and identify signs of intracranial hypertension. The advantages of the method are complete safety, non-invasiveness, high information content for diagnosing intracranial hypertension, possibility and convenience for dynamic studies, and use for assessing the effectiveness of therapy.

Electroencephalography (EEG). EEG is a method of recording the bioelectrical activity of the brain. Electroencephalography(EEG) often plays a decisive role in the diagnosis of diseases manifested by attacks of loss of consciousness, convulsions, falls, fainting, and vegetative crises.

EEG is necessary in the diagnosis of diseases such as epilepsy, narcolepsy, paroxysmal dystonia, panic attacks, hysteria, and drug intoxication.

EEG Power Spectral Analysis- quantitative analysis of the state of bioelectrical activity of the brain, associated with the ratio of various rhythmic components and determination of their individual severity. This method allows you to objectively assess the characteristics of the functional state of the brain, which is important when clarifying the diagnosis, prognosis of the course of the disease and developing treatment tactics for the patient.

EEG mapping- graphical display of the power distribution of dynamic electric fields reflecting the functioning of the brain. In a number of diseases, bioelectrical activity can change in strictly defined areas of the brain, the ratio of activity of the right and left hemispheres, the anterior and posterior parts of the brain responsible for different functions is disrupted. EEG mapping helps the neurologist to gain a more complete understanding of the participation of individual brain structures in the pathological process and the disruption of their coordinated activity.

Our clinic for diagnostics (research) of the nervous system has a new portable sleep research system "Embletta" (Iceland). This system allows you to record snoring, breathing, movement of the chest and abdominal walls, blood oxygen saturation and objectively determine whether there are pauses in breathing during sleep. Unlike other sleep study methods, you will not need to travel to a special sleep laboratory to conduct this study. A specialist from our clinic will come to your home and install the system in a familiar and comfortable environment for you. The system itself will record your sleep indicators without the participation of a doctor. When there are no distractions, your sleep is closest to normal, which means you will be able to register all the symptoms that worry you. When identifying signs of sleep apnea syndrome, the most effective treatment is by creating continuous positive pressure in the airways. The method is called CPAP therapy (an abbreviation of the English words Continuous Positive Airway Pressure - constant positive pressure in the respiratory tract).

Slow potentials- a method that allows you to get an idea of ​​the level of energy expenditure of the brain. The method is important when examining patients with muscular dystonia, Parkinson's disease, chronic cerebrovascular insufficiency, asthenia, and depression.

Evoked potentials of the brain - evoked potentials (EP) - bioelectrical activity of the brain that occurs in response to the presentation of visual, auditory stimuli, or in response to electrical stimulation of peripheral nerves (median, tibial, trigeminal, etc.).

Accordingly, visual EPs, auditory EPs and somatosensory EPs are distinguished. Registration of bioelectrical activity is carried out by surface electrodes applied to the skin in various areas of the head.

Visual VPs - make it possible to assess the functional state of the visual pathway along the entire length from the retina to the cortical representation. VEPs are one of the most informative methods for diagnosing multiple sclerosis, damage to the optic nerve of various etiologies (inflammation, tumor, etc.).

Visual evoked potentials are a research method that allows you to study the visual system, determine the presence or absence of damage from the retina to the cerebral cortex. This study helps in the diagnosis of multiple sclerosis, retrobulbar neuritis, etc., and also allows us to determine the prognosis of visual impairment in diseases such as glaucoma, temporal arteritis, diabetes mellitus and some others.

Auditory VPs- allow you to test the function of the auditory nerve, as well as accurately localize the lesion in the so-called stem cerebral structures. Pathological changes in EP of this modality are found in multiple sclerosis, tumors of deep localization, acoustic neuritis, etc.

Auditory evoked potentials - method for studying the auditory system. The information obtained through this method has great diagnostic value, as it makes it possible to determine the level and nature of damage to the auditory and vestibular system along its entire length from the ear receptors to the cerebral cortex. This study is necessary for people suffering from dizziness, hearing loss, noise and ringing in the ears, and vestibular disorders. The method is also useful in examining patients with pathologies of the ENT organs (otitis media, otosclerosis, sensorineural hearing loss)

Somatosensory EPs- contain valuable information about the conductive function of the pathways of the so-called somatosensory analyzer (receptors of muscles and joints, etc.). The use of this technique is most justified when diagnosing damage to the central nervous system (for example, multiple sclerosis), as well as damage to the brachial plexus.

Evoked somatosensory potentials - the method allows you to study the state of the sensitive system from the receptors of the skin of the hands and feet to the cerebral cortex. Plays an important role in the diagnosis of multiple sclerosis, funicular myelosis, polyneuropathy, Strumpel's disease, and various diseases of the spinal cord. The method is important in excluding a severe progressive disease - amyotrophic lateral sclerosis. This study is necessary for people with complaints of numbness in the arms and legs, impaired pain, temperature and other types of sensitivity, instability when walking, and dizziness.

Trigeminal VPs- (with stimulation of the trigeminal nerve) are a recognized method for assessing the functional state of the trigeminal nerve system. The study of trigeminal VP is indicated for neuropathy, trigeminal neuralgia, and headaches.

Trigeminal evoked potentials- study of the trigeminal nerve system - the nerve that provides sensitivity in the face and head. The method is informative in cases of suspected diseases such as trigeminal neuropathy (traumatic, infectious, compression, dysmetabolic origin), trigeminal neuralgia, and is also valuable in the study of patients with neurodental disorders, migraines, and facial pain.

Evoked cutaneous sympathetic potentials- a method for studying the state of the autonomic nervous system. The ANS is responsible for functions such as sweating, vascular tone, respiratory rate and heart rate. Its functions can be impaired either in the direction of decreasing its activity or increasing it. This is important in the diagnosis and treatment of autonomic disorders, which can be a manifestation of both primary (benign, inorganic) diseases (for example, local palmar hyperhidrosis, Raynaud's disease, orthostatic syncope) and serious organic diseases (Parkinson's disease, syringomyelia, vascular myelopathy ).

Transcranial magnetic stimulation- a method for studying various levels of the nervous system responsible for movement and strength, allows you to identify disorders from the cerebral cortex to the muscles, and assess the excitability of nerve cells in the cerebral cortex. The method is used in the diagnosis of multiple sclerosis and movement disorders, as well as for an objective assessment of the degree of damage to the motor pathways during paresis and paralysis (after a stroke, spinal cord injury).

Determination of conduction velocity along motor nerves- a study that provides information about the integrity and function of the peripheral motor nerves of the arms and legs. It is performed for patients who complain of decreased strength/weakness in muscles or muscle groups, which may be a consequence of damage to peripheral motor nerves when they are compressed by spasmodic muscles and/or osteoarticular structures, with polyneuropathies of various origins, and with limb injuries. The results of the study help develop treatment tactics and determine indications for surgical intervention.

Determination of conduction velocity along sensory nerves- a technique that allows you to obtain information about the integrity and functions of the peripheral sensory nerves of the arms and legs, identify hidden disorders (when there are no symptoms of the disease), determine indications for preventive therapy, and in some cases, exclude the organic nature of the disease. It is extremely important in the diagnosis of neurological manifestations and complications of diabetes mellitus, alcoholism, chronic and acute intoxication, viral damage to peripheral nerves, metabolic disorders and some other pathological conditions. The study is carried out for patients who complain of numbness, burning, tingling and other sensory disturbances in the arms and legs.

Blink reflex- the study is carried out to assess the speed of impulses in the trigeminal-facial nerve system, in order to study the functional state of the deep structures (stem) of the brain. The method is indicated for people suffering from facial pain, suspected damage to the trigeminal or facial nerves, or neurodental problems.

Exteroceptive suppression of voluntary muscle activity- the method is based on the assessment of the trigeminal-trigeminal reflex, which makes it possible to examine the sensory and motor fibers of the trigeminal nerve and the associated brain structures. The method is highly informative for diseases of the trigeminal nerve, facial and headaches, other chronic pain syndromes including pathology of the temporomandibular joint, as well as various polyneuropathies.

Electroneuromyography (ENMG). Electroneuromyography is a study of the biopotentials of muscles (nerves) using special electrodes at rest and during functional activation.

Electroneuromyography refers to electrodiagnostic studies and is in turn divided into needle EMG, stimulation EMG and electroneurography. The method makes it possible to diagnose diseases of the peripheral nervous system, manifested by numbness, pain in the limbs, weakness, increased muscle fatigue, and paralysis. ENMG is also informative for a number of other diseases: neuritis of the trigeminal, facial nerves, facial hemispasm, etc.

Study of F-wave, H-reflex- special methods for assessing the integrity and functions of spinal cord segments, spinal nerve roots, nerve fibers responsible for maintaining muscle tone. These studies are used for the objective diagnosis of radicular syndromes (so-called “radiculitis”), compression of the spinal nerves, increased muscle tone (eg, spasticity after a stroke, rigidity in Parkinson’s disease).

Methods for studying the nervous system

The main methods for studying the central nervous system and the neuromuscular system are electroencephalography (EEG), rheoencephalography (REG), electromyography (EMG), which determine static stability, muscle tone, tendon reflexes, etc.

Electroencephalography (EEG) - a method for recording electrical activity (biocurrents) of brain tissue for the purpose of objective assessment of the functional state of the brain. It is of great importance for diagnosing brain injury, vascular and inflammatory diseases of the brain, as well as for monitoring the functional state of an athlete, identifying early forms of neuroses, for treatment and for selection into sports sections (especially boxing, karate and other sports related with blows to the head).
When analyzing data obtained both at rest and under functional loads, various external influences in the form of light, sound, etc.), the amplitude of the waves, their frequency and rhythm are taken into account. In a healthy person, alpha waves predominate (oscillation frequency 8-12 per 1 s), recorded only when the subject’s eyes are closed. In the presence of afferent light impulses with open eyes, the alpha rhythm completely disappears and is restored again when the eyes are closed. This phenomenon is called the fundamental rhythm activation reaction. Normally it should be registered.
In 35-40% of people in the right hemisphere, the amplitude of alpha waves is slightly higher than in the left, and there is also some difference in the frequency of oscillations - by 0.5-1 oscillations per second.
With head injuries, the alpha rhythm is absent, but oscillations of high frequency and amplitude and slow waves appear.
In addition, the EEG method can diagnose early signs of neuroses (overwork, overtraining) in athletes.

Rheoencephalography (REG) - a method for studying cerebral blood flow, based on recording rhythmic changes in the electrical resistance of brain tissue due to pulse fluctuations in the blood supply of blood vessels.
The rheoencephalogram consists of repeating waves and teeth. When assessing it, the characteristics of the teeth, the amplitude of the rheographic (systolic) waves, etc. are taken into account.
The state of vascular tone can also be judged by the steepness of the ascending phase. Pathological indicators are deepening of the incisura and an increase in the dicrotic tooth with a shift downward along the descending part of the curve, which characterizes a decrease in the tone of the vessel wall.
The REG method is used in the diagnosis of chronic disorders of cerebral circulation, vegetative-vascular dystonia, headaches and other changes in the blood vessels of the brain, as well as in the diagnosis of pathological processes resulting from injuries, concussions and diseases that secondary affect blood circulation in the cerebral vessels (cervical osteochondrosis , aneurysms, etc.).

Electromyography (EMG) - a method for studying the functioning of skeletal muscles by recording their electrical activity - biocurrents, biopotentials. Electromyographs are used to record EMG. The removal of muscle biopotentials is carried out using surface (overhead) or needle-shaped (injected) electrodes. When studying the muscles of the limbs, electromyograms are most often recorded from the muscles of the same name on both sides. First, resting EM is recorded with the entire muscle in the most relaxed state, and then with its tonic tension.
Using EMG, it is possible to determine at an early stage (and prevent the occurrence of muscle and tendon injuries) changes in muscle biopotentials, to judge the functional capacity of the neuromuscular system, especially the muscles most loaded in training. Using EMG, in combination with biochemical studies (determination of histamine, urea in the blood), early signs of neuroses (overfatigue, overtraining) can be determined. In addition, multiple myography determines the work of muscles in the motor cycle (for example, in rowers, boxers during testing). EMG characterizes muscle activity, the state of the peripheral and central motor neuron.
EMG analysis is given by amplitude, shape, rhythm, frequency of potential oscillations and other parameters. In addition, when analyzing EMG, the latent period between the signal for muscle contraction and the appearance of the first oscillations on the EMG and the latent period for the disappearance of oscillations after the command to stop contractions are determined.

Chronaximetry - a method for studying the excitability of nerves depending on the time of action of the stimulus. First, the rheobase is determined - the current strength that causes the threshold contraction, and then the chronaxy. Chronancy is the minimum time for a current of two rheobases to pass, which gives the minimum reduction. Chronaxy is calculated in sigmas (thousandths of a second).
Normally, the chronaxy of various muscles is 0.0001-0.001 s. It has been established that proximal muscles have less chronaxy than distal ones. The muscle and the nerve that innervates it have the same chronaxy (isochronism). Synergistic muscles also have the same chronaxy. On the upper limbs, the chronaxy of the flexor muscles is two times less than the chronaxy of the extensor muscles; on the lower limbs, the opposite ratio is observed.
In athletes, muscle chronaxy sharply decreases and the difference in chronaxy (anisochronaxy) of flexors and extensors may increase due to overtraining (overfatigue), myositis, paratenonitis of the gastrocnemius muscle, etc.

Stability in static position can be studied using stabilography, tremorography, Romberg test, etc.
Romberg test reveals imbalance in a standing position. Maintaining normal coordination of movements occurs due to the joint activity of several parts of the central nervous system. These include the cerebellum, vestibular apparatus, conductors of deep muscle sensitivity, and the cortex of the frontal and temporal regions. The central organ for coordinating movements is the cerebellum. The Romberg test is carried out in four modes with a gradual decrease in the support area. In all cases, the subject's hands are raised forward, fingers spread and eyes closed. “Very good” if in each pose the athlete maintains balance for 15 seconds and there is no body swaying, trembling of the hands or eyelids (tremor). For tremor, a “satisfactory” rating is given. If the balance is disturbed within 15 s, the test is assessed as “unsatisfactory”. This test is of practical use in acrobatics, gymnastics, trampolining, figure skating and other sports where coordination is important.

Determination of balance in static poses
Regular training helps improve coordination of movements. In a number of sports (acrobatics, artistic gymnastics, diving, figure skating, etc.) this method is an informative indicator in assessing the functional state of the central nervous system and neuromuscular system. With overwork, head injury and other conditions, these indicators change significantly.
Yarotsky test allows you to determine the sensitivity threshold of the vestibular analyzer. The test is performed in the initial standing position with eyes closed, while the athlete, on command, begins rotational movements of the head at a fast pace. The time of head rotation until the athlete loses balance is recorded. In healthy individuals, the time to maintain balance is on average 28 s, in trained athletes - 90 s or more. The sensitivity level threshold of the vestibular analyzer mainly depends on heredity, but under the influence of training it can be increased.
Finger-nose test. The subject is asked to touch the tip of his nose with his index finger with his eyes open and then with his eyes closed. Normally, there is a hit, touching the tip of the nose. In case of brain injuries, neuroses (overwork, overtraining) and other functional conditions, there is a miss (miss), trembling (tremor) of the index finger or hand.
Tapping test determines the maximum frequency of hand movements.
To carry out the test, you must have a stopwatch, a pencil and a sheet of paper, which is divided into four equal parts by two lines. Dots are placed in the first square for 10 seconds at maximum speed, then a 10-second rest period and the procedure is repeated again from the second square to the third and fourth. The total duration of the test is 40 s. To evaluate the test, count the number of dots in each square. Trained athletes have a maximum frequency of wrist movements of more than 70 in 10 seconds. A decrease in the number of points from square to square indicates insufficient stability of the motor sphere and nervous system. The decrease in the lability of nervous processes occurs in steps (with an increase in the frequency of movements in the 2nd or 3rd squares) - indicating a slowdown in the processes of processing. This test is used in acrobatics, fencing, gaming and other sports.

Nervous system research, analyzers.
Kinesthetic sensitivity is examined with a hand dynamometer. First, the maximum force is determined. Then the athlete, looking at the dynamometer, squeezes it 3-4 times with a force equal to, for example, 50% of the maximum. Then this effort is repeated 3-5 times (pauses between repetitions are 30 s), without visual control. Kinesthetic sensitivity is measured by the deviation from the obtained value (in percent). If the difference between the given and actual effort does not exceed 20%, kinesthetic sensitivity is assessed as normal.

Muscle tone study.
Muscle tone is a certain degree of normally observed muscle tension, which is maintained reflexively. The afferent part of the reflex arc is formed by conductors of muscle-articular sensitivity, carrying impulses from proprioceptors of muscles, joints and tendons to the spinal cord. The efferent part is the peripheral motor neuron. In addition, the cerebellum and extrapyramidal system are involved in the regulation of muscle tone. Muscle tone is determined by V.I. tonometer. Dubrovsky and E.I. Deryabina (1973) in a calm state (plastic tone) and tension (contractile tone).
An increase in muscle tone is called muscle hypertension (hypertonicity), no change is called atony, a decrease is called hypotension.
An increase in muscle tone is observed with fatigue (especially chronic), with injuries and diseases of the musculoskeletal system (MSA) and other functional disorders. A decrease in tone is observed with prolonged rest, lack of training in athletes, after removal of plaster casts, etc.

Reflex Research .
Reflex is the basis of the activity of the entire nervous system. Reflexes are divided into unconditioned (innate reactions of the body to various exteroceptive and interoceptive stimuli) and conditioned (new temporary connections developed on the basis of unconditioned reflexes as a result of the individual experience of each person).
Depending on the site of evocation of the reflex (reflexogenic zone), all unconditioned reflexes can be divided into superficial, deep, distant and reflexes of internal organs. In turn, superficial reflexes are divided into cutaneous and mucous membranes; deep - tendon, periosteal and articular; distant - for light, auditory and olfactory.
When examining abdominal reflexes, to completely relax the abdominal wall, the athlete needs to bend his legs at the knee joints. Using a blunt needle or quill pen, the doctor makes a line irritation 3-4 fingers above the navel parallel to the costal arch. Normally, contraction of the abdominal muscles on the corresponding side is observed.
When examining the plantar reflex, the doctor stimulates along the inner or outer edge of the sole. Normally, there is flexion of the toes.
Deep reflexes (knee, Achilles tendon, biceps, triceps) are among the most constant. The knee reflex is caused by striking the quadriceps tendon below the kneecap with a hammer; Achilles reflex - hitting the Achilles tendon with a hammer; the triceps reflex is caused by a blow to the triceps tendon above the olecranon; biceps reflex - with a blow to the tendon in the elbow bend. The blow with a hammer is applied abruptly, evenly, precisely on a given tendon.
With chronic fatigue, athletes experience a decrease in tendon reflexes, and with neuroses - an increase. With osteochondrosis, lumbosacral radiculitis, neuritis and other diseases, a decrease or disappearance of reflexes is observed.

Studies of visual acuity, color perception, visual field.
Visual acuity is examined using tables located at a distance of 5 m from the subject. If he distinguishes 10 rows of letters on the table, then visual acuity is equal to one, but if only large letters, the 1st row, are distinguished, then visual acuity is 0.1, etc. d. Visual acuity is of great importance when selecting for sports.
So, for example, for divers, weightlifters, boxers, wrestlers with vision of -5 and below, sports are contraindicated!
Color perception is studied using a set of colored strips of paper. With injuries (lesions) to the subcortical visual centers and partially or completely to the cortical zone, color recognition is impaired, most often red and green. If color vision is impaired, auto and cycling and many other sports are contraindicated.
The field of view is determined by the perimeter. This is a metal arc attached to a stand and rotating around a horizontal axis. The inner surface of the arc is divided into degrees (from zero at the center to 90°). The number of degrees marked on the arc shows the boundary of the field of view. The boundaries of the normal field of vision for white color: internal - 60°; lower - 70°; upper - 60°. 90° indicates deviations from the norm.
Evaluation of the visual analyzer is important in team sports, acrobatics, artistic gymnastics, trampolining, fencing, etc.
Hearing examination. Hearing acuity is examined at a distance of 5 m. The doctor pronounces the words in a whisper and offers to repeat them. In case of injury or illness, hearing loss is observed (auditory neuritis). Most often observed in boxers, water polo players, shooters, etc.
Research of analyzers. A complex functional system consisting of a receptor, an afferent pathway and a zone of the cerebral cortex where this type of sensitivity is projected is referred to as an analyzer.
The central nervous system (CNS) receives information about the external world and the internal state of the body from reception organs specialized in the perception of irritations. Many reception organs are called sense organs, because as a result of their irritation and the receipt of impulses from them in the cerebral hemispheres, sensations, perceptions, ideas arise, that is, various forms of sensory reflection of the external world.
As a result of information from receptors entering the central nervous system, various acts of behavior arise and general mental activity is built.

Concentration and stability attention is determined using the “mangled lines” blank test technique. There are 25 intertwined lines on the form, starting on the left and ending on the right. On the left, the lines are numbered. The subject visually traces the progress of each line, putting down the number on the right

under which the line began on the left. The task is assessed based on the time it takes to complete it and the number of errors, determined using a standard form.

Attention span can be explored using the “number arrangement” technique. The subject receives a form with the image of two squares, divided into 25 cells each. The cells in the upper square contain various two-digit numbers in a random order; the cells in the lower square are free. The subject’s task is to sequentially fill the cells of an empty square with the numbers that are written in the upper square, in ascending order, for 2 minutes. The test is carried out using a standard. The number of entered numbers and the number of errors are counted. If only 12-13 cells are correctly filled, we can talk about insufficient attention; filling 17-18 cells or more indicates a good amount of attention. The percentage of incorrect answers in relation to the total number of numbers placed is also calculated.

To assess ability switching attention, the following technique is used. In a square of 49 cells, numbers from 1 to 25 are printed in random order in black and from 1 to 24 in red. The subject names, showing first in forward order, all the black numbers, and then in reverse order - the red ones. When the test takes less than 4 minutes, we can talk about a good result, more than 4 minutes - about an insufficient level of switching attention,

Study memory involves assessing the ability to remember a certain amount of information. The “memory for numbers” test assesses the ability to directly memorize. The subject is presented with a table with 10 two-digit numbers within 3 seconds, after which he must write down the remembered numbers within 1 minute. Reproducing them after 30 or 40 minutes allows us to judge long-term memory. When assessing the results, the total number of numbers that the subject remembers is taken into account.

The “memory for numbers” test can be replaced with the “memory for words” test. At the same time, the researcher reads out 10 words in an even voice, which are not complex and are not logically related to each other. After reading, the subject must reproduce them. Memory is assessed using a 4-point system: memorizing 8-10 words (numbers) indicates excellent memory, 6-7 - good, 4-5 - satisfactory, less than 4 - poor.

For registration speed and simple visual (auditory) motor reaction A universal chronoreflexometer is used. The subject sits in front of the remote unit of the device, which receives light or sound signals and has a built-in button that stops the electronic time counter. The subject, holding his finger on the button, must press it as quickly as possible after the signal is given. The researcher sits in front of the control panel and by pressing a key (toggle switch) gives one or another signal. After the subject presses the button, the signal turns off, and the counter records the hidden reaction time in milliseconds. You can give a series of 10 consecutive signals, then calculating the average latent period of a simple motor reaction.

The study of the mobility of nervous processes in the visual or auditory analyzer is also carried out to assess the functional state of the central nervous system. To determine the critical flicker fusion frequency (CFFF), the subject is presented with a series of light signals, the flicker speed of which is changed using a potentiometer. The subject must set the minimum flickering frequency at which the light signal is perceived by him as continuous.

Determination of the critical frequency of fusion of sound vibrations is carried out as follows: the subject is given sound pulses from a generator through headphones, the frequency of which can smoothly change. Pulses are supplied with a gradual increase in their frequency to a maximum. The subject establishes the moment when individual sound impulses merge into a solid tone.

Electroencephalography (EEG) refers to objective instrumental methods for studying the functional state of the central nervous system and is a recording of the bioelectrical activity of the brain.

Normal physiology: lecture notes Svetlana Sergeevna Firsova

7. Methods for studying the central nervous system

7. Methods for studying the central nervous system

There are two large groups of methods for studying the central nervous system:

1) experimental method, which is carried out on animals;

2) a clinical method that is applicable to humans.

To the number experimental methods classical physiology includes methods aimed at activating or suppressing the nerve formation being studied. These include:

1) method of transverse section of the central nervous system at various levels;

2) method of extirpation (removal of various parts, denervation of the organ);

3) method of irritation by activation (adequate irritation - irritation with an electrical impulse similar to a nervous one; inadequate irritation - irritation with chemical compounds, graded irritation with electric current) or suppression (blocking the transmission of excitation under the influence of cold, chemical agents, direct current);

4) observation (one of the oldest methods of studying the functioning of the central nervous system that has not lost its significance. It can be used independently, and is often used in combination with other methods).

Experimental methods are often combined with each other when conducting experiments.

Clinical method aimed at studying the physiological state of the central nervous system in humans. It includes the following methods:

1) observation;

2) method of recording and analyzing electrical potentials of the brain (electro-, pneumo-, magnetoencephalography);

3) radioisotope method (investigates neurohumoral regulatory systems);

4) conditioned reflex method (studies the functions of the cerebral cortex in the mechanism of learning and the development of adaptive behavior);

5) questionnaire method (assesses the integrative functions of the cerebral cortex);

6) modeling method (mathematical modeling, physical modeling, etc.). A model is an artificially created mechanism that has a certain functional similarity with the mechanism of the human body being studied;

7) cybernetic method (studies control and communication processes in the nervous system). Aimed at studying organization (systemic properties of the nervous system at various levels), management (selection and implementation of influences necessary to ensure the functioning of an organ or system), information activity (the ability to perceive and process information - an impulse in order to adapt the body to environmental changes).

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Methods of studying taijiquan Movements in taijiquan gymnastics are quite complex, and they often involve turning the body, various movements of the legs, changing directions, and much more. Those who begin to practice, usually paying attention to their hands, forget about their feet,

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Briefly about the history of the study of dysbiosis The smallest organisms have been of interest to scientists for a long time. Researchers have been studying the role of microbes living in the environment, as well as on the surface of the human body (skin and mucous membranes) and in some organs, since the end of the 19th century.

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Methods for studying the functions of the digestive tract The study of the secretory and motor activity of the gastrointestinal tract is carried out both in humans and in experiments on animals. Chronic studies play a special role, when the animal is first

The study of the central nervous system includes a group of experimental and clinical methods. Experimental methods include cutting, extirpation, destruction of brain structures, as well as electrical stimulation and electrical coagulation. Clinical methods include electroencephalography, evoked potentials, tomography, etc.

Experimental methods

1. Cut and cut method. The method of cutting and switching off various parts of the central nervous system is done in various ways. Using this method, you can observe changes in conditioned reflex behavior.

2. Methods of cold switching off brain structures make it possible to visualize the spatio-temporal mosaic of electrical processes in the brain during the formation of a conditioned reflex in different functional states.

3. Methods of molecular biology are aimed at studying the role of DNA, RNA molecules and other biologically active substances in the formation of a conditioned reflex.

4. The stereotactic method consists in introducing an electrode into the animal’s subcortical structures, with which one can irritate, destroy, or inject chemicals. Thus, the animal is prepared for a chronic experiment. After the animal recovers, the conditioned reflex method is used.

Clinical methods

Clinical methods make it possible to objectively assess the sensory functions of the brain, the state of the pathways, the brain’s ability to perceive and analyze stimuli, as well as identify pathological signs of disruption of the higher functions of the cerebral cortex.

Electroencephalography

Electroencephalography is one of the most common electrophysiological methods for studying the central nervous system. Its essence lies in recording rhythmic changes in the potentials of certain areas of the cerebral cortex between two active electrodes (bipolar method) or an active electrode in a certain zone of the cortex and a passive electrode superimposed on an area remote from the brain.

Electroencephalogram is a recording curve of the total potential of the constantly changing bioelectrical activity of a significant group of nerve cells. This amount includes synaptic potentials and partly action potentials of neurons and nerve fibers. Total bioelectrical activity is recorded in the range from 1 to 50 Hz from electrodes located on the scalp. The same activity from the electrodes, but on the surface of the cerebral cortex is called electrocorticogram. When analyzing EEG, the frequency, amplitude, shape of individual waves and the repeatability of certain groups of waves are taken into account.

Amplitude measured as the distance from the baseline to the peak of the wave. In practice, due to the difficulty of determining the baseline, peak-to-peak amplitude measurements are used.

Under frequency refers to the number of complete cycles completed by a wave in 1 second. This indicator is measured in hertz. The reciprocal of the frequency is called period waves. The EEG records 4 main physiological rhythms: ά -, β -, θ -. and δ – rhythms.

α – rhythm has a frequency of 8-12 Hz, amplitude from 50 to 70 μV. It predominates in 85-95% of healthy people over nine years of age (except for those born blind) in a state of quiet wakefulness with eyes closed and is observed mainly in the occipital and parietal regions. If it dominates, then the EEG is considered as synchronized.

Synchronization reaction called an increase in amplitude and a decrease in frequency of the EEG. The EEG synchronization mechanism is associated with the activity of the output nuclei of the thalamus. A variant of the ά-rhythm are “sleep spindles” lasting 2-8 seconds, which are observed when falling asleep and represent regular alternations of increasing and decreasing amplitude of waves in the frequencies of the ά-rhythm. Rhythms of the same frequency are:

μ – rhythm, recorded in the Rolandic sulcus, having an arched or comb-shaped waveform with a frequency of 7-11 Hz and an amplitude of less than 50 μV;

κ - rhythm, noted when applying electrodes in the temporal lead, having a frequency of 8-12 Hz and an amplitude of about 45 μV.

β - rhythm has a frequency from 14 to 30 Hz and a low amplitude - from 25 to 30 μV. It replaces the ά rhythm during sensory stimulation and emotional arousal. The β rhythm is most pronounced in the precentral and frontal areas and reflects a high level of functional activity of the brain. The change from ά - rhythm (slow activity) to β - rhythm (fast low-amplitude activity) is called desynchronization EEG is explained by the activating influence on the cerebral cortex of the reticular formation of the brainstem and the limbic system.

θ – rhythm has a frequency from 3.5 to 7.5 Hz, amplitude from 5 to 200 μV. In a waking person, the θ rhythm is usually recorded in the anterior regions of the brain during prolonged emotional stress and is almost always recorded during the development of the phases of slow-wave sleep. It is clearly registered in children who are in a state of displeasure. The origin of the θ rhythm is associated with the activity of the bridge synchronizing system.

δ – rhythm has a frequency of 0.5-3.5 Hz, amplitude from 20 to 300 μV. Occasionally recorded in all areas of the brain. The appearance of this rhythm in a awake person indicates a decrease in the functional activity of the brain. Stably fixed during deep slow-wave sleep. The origin of the δ - EEG rhythm is associated with the activity of the bulbar synchronizing system.

γ – waves have a frequency of more than 30 Hz and an amplitude of about 2 μV. Localized in the precentral, frontal, temporal, parietal areas of the brain. When visually analyzing the EEG, two indicators are usually determined: the duration of the ά-rhythm and the blockade of the ά-rhythm, which is recorded when a particular stimulus is presented to the subject.

In addition, the EEG has special waves that differ from the background ones. These include: K-complex, λ - waves, μ - rhythm, spike, sharp wave.

K - complex- This is a combination of a slow wave with a sharp wave, followed by waves with a frequency of about 14 Hz. The K-complex occurs during sleep or spontaneously in a waking person. The maximum amplitude is observed in the vertex and usually does not exceed 200 μV.

Λ – waves- monophasic positive sharp waves arising in the occipital area associated with eye movements. Their amplitude is less than 50 μV, frequency is 12-14 Hz.

M – rhythm– a group of arc-shaped and comb-shaped waves with a frequency of 7-11 Hz and an amplitude of less than 50 μV. They are registered in the central areas of the cortex (Roland's sulcus) and are blocked by tactile stimulation or motor activity.

Spike– a wave clearly different from background activity, with a pronounced peak lasting from 20 to 70 ms. Its primary component is usually negative. Spike-slow wave is a sequence of superficially negative slow waves with a frequency of 2.5-3.5 Hz, each of which is associated with a spike.

sharp wave– a wave that differs from background activity with an emphasized peak lasting 70-200 ms.

At the slightest attraction of attention to a stimulus, desynchronization of the EEG develops, that is, a reaction of ά-rhythm blockade develops. A well-defined ά-rhythm is an indicator of the body’s rest. A stronger activation reaction is expressed not only in the blockade of the ά - rhythm, but also in the strengthening of high-frequency components of the EEG: β - and γ - activity. A decrease in the level of functional state is expressed in a decrease in the proportion of high-frequency components and an increase in the amplitude of slower rhythms - θ- and δ-oscillations.

Method for recording impulse activity of nerve cells

The impulse activity of individual neurons or a group of neurons can be assessed only in animals and, in some cases, in humans during brain surgery. To record neural impulse activity of the human brain, microelectrodes with tip diameters of 0.5-10 microns are used. They can be made of stainless steel, tungsten, platinum-iridium alloys or gold. The electrodes are inserted into the brain using special micromanipulators, which allow the electrode to be precisely positioned to the desired location. The electrical activity of an individual neuron has a certain rhythm, which naturally changes under different functional states. The electrical activity of a group of neurons has a complex structure and on a neurogram looks like the total activity of many neurons, excited at different times, differing in amplitude, frequency and phase. The received data is processed automatically using special programs.

Evoked potential method

The specific activity associated with a stimulus is called an evoked potential. In humans, this is the registration of fluctuations in electrical activity that appear on the EEG with a single stimulation of peripheral receptors (visual, auditory, tactile). In animals, afferent pathways and switching centers of afferent impulses are also irritated. Their amplitude is usually small, therefore, to effectively isolate evoked potentials, the technique of computer summation and averaging of EEG sections that was recorded during repeated presentation of the stimulus is used. The evoked potential consists of a sequence of negative and positive deviations from the baseline and lasts about 300 ms after the end of the stimulus. The amplitude and latency period of the evoked potential are determined. Some of the components of the evoked potential, which reflect the entry of afferent excitations into the cortex through specific nuclei of the thalamus, and have a short latent period, are called primary response. They are registered in the cortical projection zones of certain peripheral receptor zones. Later components that enter the cortex through the reticular formation of the brainstem, nonspecific nuclei of the thalamus and limbic system and have a longer latent period are called secondary responses. Secondary responses, unlike primary ones, are recorded not only in the primary projection zones, but also in other areas of the brain, connected by horizontal and vertical nerve pathways. The same evoked potential can be caused by many psychological processes, and the same mental processes can be associated with different evoked potentials.

Tomographic methods

Tomography– is based on obtaining images of brain slices using special techniques. The idea of ​​this method was proposed by J. Rawdon in 1927, who showed that the structure of an object can be reconstructed from the totality of its projections, and the object itself can be described by many of its projections.

CT scan is a modern method that allows you to visualize the structural features of the human brain using a computer and an X-ray machine. In a CT scan, a thin beam of X-rays is passed through the brain, the source of which rotates around the head in a given plane; The radiation passing through the skull is measured by a scintillation counter. In this way, X-ray images of each part of the brain are obtained from different points. Then, using a computer program, these data are used to calculate the radiation density of the tissue at each point of the plane under study. The result is a high-contrast image of a brain slice in a given plane. Positron emission tomography– a method that allows you to assess metabolic activity in different parts of the brain. The test subject ingests a radioactive compound, which makes it possible to trace changes in blood flow in a particular part of the brain, which indirectly indicates the level of metabolic activity in it. The essence of the method is that each positron emitted by a radioactive compound collides with an electron; in this case, both particles mutually annihilate with the emission of two γ-rays at an angle of 180°. These are detected by photodetectors located around the head, and their registration occurs only when two detectors located opposite each other are excited simultaneously. Based on the data obtained, an image is constructed in the appropriate plane, which reflects the radioactivity of different parts of the studied volume of brain tissue.

Nuclear magnetic resonance method(NMR imaging) allows you to visualize the structure of the brain without the use of X-rays and radioactive compounds. A very strong magnetic field is created around the subject's head, which affects the nuclei of hydrogen atoms, which have internal rotation. Under normal conditions, the rotation axes of each core have a random direction. In a magnetic field, they change orientation in accordance with the lines of force of this field. Turning off the field leads to the fact that the atoms lose the uniform direction of the axes of rotation and, as a result, emit energy. This energy is recorded by a sensor, and the information is transmitted to a computer. The cycle of exposure to the magnetic field is repeated many times and as a result, a layer-by-layer image of the subject’s brain is created on the computer.

Rheoencephalography

Rheoencephalography is a method for studying the blood circulation of the human brain, based on recording changes in the resistance of brain tissue to high-frequency alternating current depending on the blood supply and allows one to indirectly judge the amount of total blood supply to the brain, the tone, elasticity of its vessels and the state of venous outflow.

Echoencephalography

The method is based on the property of ultrasound to be reflected differently from brain structures, cerebrospinal fluid, skull bones, and pathological formations. In addition to determining the size of the localization of certain brain formations, this method allows you to estimate the speed and direction of blood flow.

Study of the functional state of the human autonomic nervous system

The study of the functional state of the ANS is of great diagnostic importance in clinical practice. The tone of the ANS is judged by the state of reflexes, as well as by the results of a number of special functional tests. Methods for clinical research of VNS are conditionally divided into the following groups:

• Patient interview;
• Study of dermographism (white, red, elevated, reflex);
• Study of vegetative pain points;
• Cardiovascular tests (capillaroscopy, adrenaline and histamine skin tests, oscillography, plethysmography, determination of skin temperature, etc.);
• Electrophysiological tests – study of electro-skin resistance using a direct current apparatus;
• Determination of the content of biologically active substances, for example catecholamines in urine and blood, determination of blood cholinesterase activity.