Cognitive functions of the brain: the structure of cognition. Cognitive functions: what is it and what disorders are possible? What does cognitive function mean?

The structure of the body is the same in all people, which cannot be said about mental abilities. One person literally grasps everything “on the fly” and is able to store a huge amount of information in his memory, while another does not succeed. The reason lies in the functioning of the brain, or more precisely in its cognitive functions. Let's consider what it is, under the influence of what factors violations arise and how they are expressed.

Literally translated from Latin, cognitio means “cognition.” And the higher ones are called cognitive brain functions, allowing a person to perceive, process and store received information. Thanks to this, people are able to interact with the environment and society.

These functions include:

1. Visual perception. With the help of this function, a person distinguishes and recognizes different stimuli. This is what makes it possible to understand what the people and objects around you look like, and also to understand the difference between, for example, a TV remote control and shoes.
2. Attention. Speaking in simple words, this function helps a person in the implementation of brain and motor activities. Thanks to her among external factors, such as sounds, smells and images, as well as internal ones, such as thoughts and emotions, a person concentrates on what will happen to him in this moment healthy.
3. Memory. This difficult process, which encodes, stores and reproduces received information. It is closely related to the ability to concentrate, since without this it is impossible to obtain information in full.
4. Executive abilities. This can also be classified as cognitive functions, since they are responsible for the relationship between fixing information and its further use. Such abilities are provided by the activity of the prefrontal cortex in the brain.
5. Speech. This communication system allows people to communicate with each other and also formulate their thoughts in a connected manner. Various people are involved in the process brain regions, located mostly in the left hemisphere.

In other words, the cognitive functions of the brain help to perceive everything that surrounds a person, formulate an idea about it and record it in memory.

Causes of brain dysfunction

Impairment of cognitive functions is considered a sure symptom that disorders in brain activity have occurred. They can be functional, when such a phenomenon is temporary, and organic, characterized by irreversible processes.

The first category includes violations provoked by the following factors:

• overwork;
• severe or prolonged stress;
• emotional and mental overload.

Organic disorders arise against the background various diseases when the process of transmitting impulses in the brain “goes wrong”.

Such a violation can be caused by:

• diabetes mellitus;
• disorders in metabolism and homeostasis processes;
• hypothyroidism;
• hypertension;
• disorders of blood circulation in the brain;
• myocardial infarction;
• traumatic brain injury;
• Alzheimer's or Parkinson's disease;
• obesity;
• use in large doses alcohol or drugs.

Cognitive functioning disorders are classified according to severity. They can be:

1. Light. In this case, the deviations are insignificant, the person has problems with memory and attention, as well as rapid fatigue.
2. Moderate. About a tenth of these disorders gradually develop into Alzheimer's disease. Over time, symptoms increase, the ability to think and remember deteriorates, and speech problems develop.
3. Heavy. Typically, these disorders occur in old age and are characterized mental disorders. A sign of this condition is disorientation in space, when a person gradually turns into a child, losing basic skills.

Attention! In the latter case, patients need care and constant intake of supportive medications. They are no longer able to care for themselves.

How to improve your mental abilities

Improving a person’s cognitive functions is facilitated by activities such as physical training and education, when he regularly acquires any new knowledge and skills. Nutrition and daily routine also affect brain activity. In addition, we need good rest and communication associated with positive emotions. There are also a number of drugs that can improve cognitive performance.

Fish fat

Everyone has known about the benefits of this product since childhood, despite the popular saying that “nothing scares the world more than the hated fish oil.” The polyunsaturated compounds present in it fatty acid, such as docosahexaenoic acid and eicosapentaenoic acid, have a beneficial effect on the heart, blood vessels and nervous system. They also help balance blood pressure and prevent the formation of blood clots. In addition, these enzymes can influence the balance of triglycerides, increased content which leads to the development of diabetes.

Acceptance of funds based on fish oil will be beneficial at any age. For a premature baby or small child positive influence is to improve visual acuity, increase cognitive abilities and normal brain development. In elderly patients, taking fish oil and other formulations containing polyunsaturated fatty acids reduces the risk of senile dementia.

Vitamin B complex

The formulation “B vitamins” combines a number of elements that have a positive effect on the human body. Without these enzymes normal functioning its impossible. As a result of taking complexes, a number of positive effects, which are provided by the specified microelements.

Let's find out more about this:

• memory improves by increasing the level of thiamine (B1) in the blood;
• indicators are restored blood pressure, blood clotting is normalized due to the content of pyridoxine (B6) in vitamin complexes;
• cholesterol and triglyceride balances are normalized, the production of omega-3 acids is activated, and the risk of vascular diseases is reduced thanks to niacin (B3);
• degradation processes slow down and the severity of memory impairment decreases thanks to cobalamin (B12);
• the amount of homocysteine ​​in the blood decreases - this is a protein, the increased content of which leads to atherosclerosis and cardiovascular diseases, as well as memory disorders, this effect is provided by folic acid (B9).

Lecithin and choline

Many people mistakenly consider lecithin and choline to be the same substance. In fact, these are closely related enzymes that affect the condition of the liver and nervous system.

Lecithin is a fatty compound that is produced by the human body. But you can get this enzyme from food, animal and plant. It contains liver, eggs, soy products, peanuts and wheat germ. This component is also found in ice cream, mayonnaise sauces, chocolate and margarine.

Choline is a component of acetylcholine that is present in the brain. It is necessary for adequate functioning of memory and muscle activity. You can get this enzyme from food by eating liver, egg yolks, soy, grape juice, cabbage and peanuts.

Lecithin and choline are part of many vitamin complexes, both group B and other multicomponent supplements.

Plant extracts

Among the products based on plant extracts that help improve brain functionality, the following stand out:

1. Gotu Kola. This plant contains many compounds that help protect the heart, blood vessels and brain matter. Preparations based on it help improve emotional state human, normalization intracranial pressure, strengthening memory, attention and intellectual capabilities.
2. Ginkgo biloba. This plant component is used in medicine in the treatment of various diseases associated with the functions of blood vessels and the brain. Drugs based on it help improve memory and thinking even in patients with Alzheimer's disease. And also with the help of these tools you can prevent a number of disorders that affect cognitive function.
3. Maritime pine extract or Pycnogenol. This connection is powerful antioxidant, and also prevents protein adhesion. It is used to protect the brain matter, and it also has a beneficial effect on nerve cells, helps prevent stroke. Reception similar drugs helps normalize mental activity, improve memory and eliminate forgetfulness.

It is important to realize that innate abilities cannot be improved even with the help of highly effective drugs. The described means will only help them to develop fully, and will also protect them from disorders that negatively affect cognitive functions.

Sometimes we forget where we left our keys. Looking for them around the apartment all day, we are surprised at our absent-mindedness and inattention, not even suspecting that these may be the first symptoms of a disorder normal operation brain. So-called cognitive disorders often appear in older people. But it also happens that young people and even children suffer from them.

Cognitive disorders. What it is?

First, let's look deeper into our brains. Gray cells perform many of their duties thanks to their active work we move physically and develop mentally. Important in the life of every person are the cognitive functions of the brain, without which we could not learn. the world. First of all, with their help we perceive, understand and process the information received in the process of cognition. This is one of the manifestations of higher nervous activity, without which a person would never be a person.

Based on this, we can conclude: cognitive disorders are disorders of an individual’s cognitive function. This is not only forgetfulness, but also a deterioration in performance and intellectual work. If you notice these symptoms in yourself or your loved ones, contact your doctor immediately. After all, at first, mild forgetfulness can gradually develop into a loss of the ability to think and reason clearly; you will not remember the basic events of the day. Then there will be disorientation in space, partial amnesia, and the ability to take care of oneself in everyday life will disappear.

Risk factors

Even if you are still far from retirement, you are not immune from this trouble, which can suddenly fall on your head, namely on what is in the middle of it - the brain. The main risk factors for cognitive impairment are severe traumatic brain injury and poisoning - in this case, the disease will be temporary, from several days to 2-3 years.

A person can get a more severe form of the disease with Parkinson’s, Alzheimer’s, vascular diseases. In this case, the disorder of cognitive functions will be progressive. Vascular diseases are the main and most common cause of loss of the ability to perceive the world around us.

Firstly, it is dangerous in this regard arterial hypertension, atherosclerotic lesions blood vessels, strokes. Secondly, the cause of cognitive disorders can be various kinds of circulatory and metabolic disorders during diabetes mellitus, hepatic and renal failure. Thirdly, a risk factor for the development of the disease is insufficient intake of vitamins E and B12 during alcohol or drug abuse.

Main symptoms

The first warning sign will be problems at work. At first, you are simply too lazy to work, you feel tired, your brain literally refuses to think and analyze. New data is not perceived, and it becomes difficult to draw conclusions. In more severe forms speech functions are impaired: a person cannot formulate a thought, it is difficult for him to find words and simply speak.

Cognitive disorders primarily affect memory. First, you forget recent events, and then memories from your youth and childhood lose clarity and are completely erased from your brain. Another symptom, but less common, is attention problems. A person is unable to concentrate on assigned tasks and goals. He constantly loses the thread of the conversation, asks again, asks to repeat this or that phrase.

All these manifestations indicate that you need to immediately contact a neurologist. Only qualified specialist can deliver accurate diagnosis and prescribe correct and effective treatment.

Mild cognitive impairment

It is a pathology of the brain, which is characterized by vascular dementia. If not treated in time, the disease goes through several stages of development: starting with minor memory impairment and ending with complete dementia. With a mild form of the disease, the patient cannot maintain attention on one subject for a long time, is unable to long time carry out mental work, feels increased fatigue.

All of these disorders have a direct connection with cerebrasthenic syndrome, which is a type of psychopathological condition. Development indicator brain activity is within the norm or deviates slightly from it. Mild cognitive impairment is usually noticed only by the patient himself; other people attribute the manifestations of the disease to simple absent-mindedness or increased fatigue At work. It is easy to cure, in contrast to the most severe cognitive disorders, which imply the patient’s dementia and complete disorientation in life.

Mild cognitive impairment

Between mild and severe disorders, doctors diagnose and moderate form diseases. A person’s cognitive functions become less pronounced, weaker than the norm for his age, but they do not yet develop into dementia. The patient will find that it is difficult for him to count, remember phrases and even words just spoken by his interlocutor, and navigate the area. From such violations found on early stages, easy to get rid of with the help of ordinary medications. Treatment of cognitive disorders is prescribed by a neurologist, taking into account consultations with a psychiatrist and other specialists.

Moderate disorders occur in 20% of people over 65 years of age. Moreover, 60% of such patients develop dementia in the next few years. In a third of cases, mild cognitive impairment is of a mild nature. People do not even notice any violations or deviations for a long time.

If a child gets sick

Oddly enough, even children can experience all the inconveniences and hardships of this disease. Usually, in the youngest patients, the cause of disorders is elementary vitamin deficiency. Eating canned, sweet and other harmful products, the child ignores vegetables and fruits, healthy cereals, meat and fish. As a result, it doesn't get everyone essential vitamins. As a result, cognitive disorders develop in children: poor performance at school, the inability to repeat or reproduce what they saw, heard or read, lack of concentration and intense thinking in class.

Today, this disease is very common among schoolchildren and adolescents. 20% of the total number of children suffers. Parents need to pay attention to their son or daughter’s performance at school, and if there is a noticeable deterioration, then adjust the student’s daily diet and include more healthy and micronutrient-rich food in the menu. If cognitive impairments are the consequences of injuries and illnesses, then you cannot do without the help of a doctor.

Treatment

Cognitive therapy for personality disorders directly depends on the cause of the disorder. In any case, it should be aimed at correction pathological changes in brain activity. In addition to the fact that doctors treat the underlying disease, to improve cognitive functions they can prescribe drugs with neuroprotective properties: Semax, Glycine, Ceraxon, Cavinton, Nootropil and others.

Be sure to prescribe medications for hypercholesterolemia. This prevents the development of cognitive impairment and serves to prevent their further progress. If the patient has severe dementia, then they may prescribe the drugs "Nicergoline", "Galantamine", "Memantine", "Donepezil". Cognitive psychotherapy personality disorders also helps relieve general state sick. He is recommended to follow a cholesterol-free diet: eat seafood, vegetables and fruits, milk and cottage cheese. Smoking and drinking alcohol should be completely avoided.

Neurologists' opinion

They claim that they are very useful activity for cognitive impairment is solving a crossword puzzle. Such leisure is gymnastics for the brain. By solving, remembering, comparing, we not only prevent the development of deviations, but also treat them if they have already manifested themselves. Doctors also advise reading poetry and memorizing them, drawing, knitting, and making crafts. These classes will rehabilitate your “gray cells” and complement the general prescribed therapy.

Neurologists say: if you find yourself with the mildest symptoms of the disease, then you can safely take the drug “Glycine” according to the instructions. Also drink vitamin complexes, ginkgo biloba and Nootropin, only in this case the dosage is determined by a specialist. Besides, cognitive therapy anxiety disorders will help improve the condition and serve as a disease prevention. Remember that self-medication often ends in exacerbation of the problem or even fatal. Therefore, at the first signs of cognitive impairment, immediately visit a specialist.

Today in our article we will talk about such an important function, which is called cognitive functions. In fact, these are the most important functions in everyone’s life, because it is thanks to them that a person can think, compose meaningful speech, express his thoughts in writing, make plans and holistically perceive the world around him.

In other words, we will consider what distinguishes man from animals, making him human.

Definition

The term “cognitive” itself is a scientific term, so it is not very often found in everyday vocabulary. And yet, this term reveals such human abilities that are familiar to everyone. It is cognitive functions that help a person find connections with the environment and build his ideas about the world as a whole.

Cognitive functions, also known as cognitive functions, are brain processes, they are aimed at ensuring that the individual can interact with others.

Human life largely depends on such a unique and important skill as the ability to remember and store information. Of course, the point of view according to which only memory is included in this definition is erroneous.

Cognitive functions are complex mechanism, this is the interconnection of complex mental processes, the level of which differs among different people.

It is important that they can be developed and trained, but it is also important to remember that these processes can be disrupted due to various factors and personality disorders.

Naturally, the ability to perceive, store and reproduce information is very important, but these processes are impossible alone; the interrelation of different processes is important here.

Higher brain functions

In order to better understand this issue, it is necessary to consider cognitive functions separately.

1. One of the most important functions is attention. It can be characterized as the ability to concentrate mental processes on a specific object. Each person has individually expressed characteristics of this process, such as:
   • Sustainability;
   • Concentration;
   • Way to switch;
   • Concentration;
   • Volume.

   All these characteristics change the quality of attention in different people. It is because of them that it turns out that some people easily remember something, while others cannot concentrate their attention. But all these characteristics can also be developed by working on yourself.

2. Other important function– this is a person’s perception. It is compiled based on information that a person receives from the senses in the form of unified images. For this function, constancy is important, in other words, an object that is perceived by a person regardless of changing conditions is always perceived as the same. For example, a person can recognize an acquaintance no matter how he is dressed or where he is. Animals are deprived of this quality, which is why a dog cannot recognize its friend who will be standing in the dark or if he is wearing different clothes.
3. Gnosis is the ability to recognize, visually identify images and compare them to categories.
4. Memory is this cognitive function makes it possible to capture, save and right time reproduce previously received information.
5. Intelligence is already the ability to “work” with the information received: to analyze, compare facts, evaluate, generalize, and so on.
6. Speech is a unique skill through which people can communicate using symbolic signs.
7. Praxis is a complex of abilities that form and include motor skills in a person’s activities and help him build, learn and automate the sequence of his movements.

Below we will look at some of the functions in more detail. Since they are deeper and broader concepts, it will also help to better understand the nature of cognitive impairment.

A few words about intelligence

Speech and intelligence can be distinguished as cognitive functions of the brain. After all, thanks to this, a person can pronounce meaningful sounds that develop into speech. The cognitive functions of the brain give an individual the opportunity to conduct a monologue even without a speech apparatus, only pronouncing words in his thoughts.

Using symbols that correspond to sounds in humans, appears and written language. And how rich a person is lexicon and whether he can construct more complex phrases is related to his intelligence. One could even say that it is a person's unified cognitive ability, which relies on human functions such as attention, perception, memory and representation.

It was intelligence that separated humans and animals. However, intelligence itself is general concept, the implementation of which requires a number of mental functions, such as: the ability to plan, predict different events, taking as a basis environment and gained experience.

In order to determine a person’s intelligence, it is necessary to take into account such person’s abilities as: learning ability, logical thinking, ability to analyze various information, as well as compare and find patterns in different phenomena.

And to characterize intelligence, the breadth and depth of thinking, logic, flexibility of mind, criticality and evidence of one’s conclusions are taken as a basis.

One of the important components of intelligence is erudition. Many people mistakenly assume that erudition and intelligence are the same thing, but this is far from true. Since an erudite merely has a large stock of knowledge, however, without intelligence, a person cannot use this “baggage” in any way, draw logical conclusions, and so on.

In order to measure intelligence today there are a number of tests. These tests are created based on a proven pattern, which says that if a person can solve certain type tasks, then he will successfully cope with other tasks.

Praxis or unique human ability

Humans have a number of important and unique cognitive abilities, one of which is praxis. This is a person’s ability to maintain a conscious sequence of his actions and movements. Praxis is the ability that appears in a person in infancy by giving the baby a rattle on his hand, thereby the parents lay the foundation for this function.

There are several types of praxis:

• Finger - when a person learns to use his fingers, then, as a result, gestures appear.
• Symbolic is already a complex of gestures that give an idea of ​​what a particular person wants to say. This is in some way reminiscent of the principle by which deaf people communicate: thanks to a set of special gestures, they can communicate without words.

Violation of this function in humans can lead to a number of undesirable consequences.

It’s probably no secret to anyone that each function is associated with a specific part of the brain. And this is natural, because every separate function has its localization in the brain. This represents separate areas of the brain that have a group of neurons, and they in turn are responsible for a certain type of nerve transmission.

For example, cognitive functions are located in the cerebral cortex. There are 3 sections:

1. Sensory – which processes signals emanating from the senses.
2. Motor – which is responsible for motor functions different parts human body.
3. Associative - it can be considered a kind of intermediary that provides communication between the sensory and motor areas.

They are responsible for thinking, both logical and abstract, for speech, planning their movements. frontal lobes cerebral cortex.

Processing of information obtained with the help of visual analyzers is carried out in the occipital lobe, while information received from hearing aids is analyzed in the temporal lobe.

There are more ancient areas of the brain that help provide basic skills for human survival.

Human memory, smell and emotions are expressed through the limbic system.

The thalamus provides redirection of impulses from different organs: vision, hearing, balance and tactile senses.
The hippocampus helps remember new information.

Awareness of one’s own “I”, consciousness, in the adaptation of the individual and in the feelings of existence - important role midbrain.

And all departments are closely connected with each other and interact by transmitting impulses by neurotransmitters: serotonins, dopamine, adrenaline, acetylcholine, etc. These neurotransmitters themselves can inhibit or accelerate cognitive tasks in humans.

From the above, it becomes clear that any disturbances: blood flow, brain damage or tumors in one area or another can cause cognitive disorders in a person.

Cognitive disorders

Even the slightest injuries can ultimately lead to various cognitive impairments. Naturally, these disorders vary in severity from mild to severe.

If you look closely at the reasons for the appearance of these violations, the factors leading to the violations can be divided into:

1. Degenerative diseases - Parkinsonism, Alzheimer's disease.
2. Vascular diseases - heart attack, stroke, atherosclerosis.
3. Metabolic problems - hypoglycemia, hepatic or renal encephalopathy, drug use (benzodiazepines, anticholinergics), hypo- or hyperthyroidism.
4. Neuroinfections.
5. Various brain injuries.
6. Brain tumor.

As for the type of violation, it will depend on the location of the influencing factor. However, this does not mean that if a violation occurs, you should give up. Not at all, because violations light form and even moderate severity Even older people can recover if correct and timely measures are taken and treated.

A few final words

Cognitive functions are abilities that are associated with the human brain and are dependent on human body generally. This is precisely the reason why in various violations, damage to the brain or body and under the influence of strong emotions, disruptions in the quality of cognitive functions are observed. When these failures reach noticeable limits, these decreases in quality are called cognitive impairment.

And this, in turn, affects a person’s entire life, affecting his various spheres: from simple everyday life to the social and professional spheres of the individual.

Fortunately, today there are many ways to combat cognitive impairment. Therefore, if you feel that you have some problems, minor impairments in cognitive functions: memory lapses, difficulties with perception, etc., then you need to fight it using one method or another.

Man differs from animals in the presence of higher nervous activity. The ability to think, communicate using meaningful speech, express it in writing, as well as perform directed actions, plan and holistically perceive reality are combined into cognitive functions.

What do cognitive functions include?

Cognitive or cognitive functions are those brain processes that are aimed at interacting with other people and the world around us. Human life is extremely dependent on the ability to remember and store information, to correctly compare known facts, assume the consequences of their actions. The degree of development of such mental processes is individual; they can be trained, but can be disrupted under the influence of various factors.

It is a mistake to believe that cognitive functions are only memory (see). The ability to perceive, store and reproduce information is important, but it is impossible without other processes.

Attention is one of these functions, which is characterized by the ability to concentrate mental processes on a specific object. Each individual has the following characteristics:

• sustainability;
• switchability;
• concentration;
• concentration;
• volume.

The function of perception is the construction of integral images based on information received from the senses. Perception is characterized by constancy: an object is defined as the same regardless of changes external conditions. This ability is not typical for animals: a dog may consider a familiar person a stranger if he is in the shadows or wears unfamiliar clothes.

Find out why this happens with age: causes.

Cognitive abilities include praxis - the ability to produce a conscious sequence of actions or movements. The ability begins to be mastered as early as infancy when a rattle is placed in a child’s hand for the first time. Then finger praxis develops - the ability to manipulate one’s fingers, and gestures appear.

A special place is occupied by symbolic praxis - these are various gestures by which one can understand what a person wants to say, imitation of holding a telephone receiver, driving a car, drinking from a glass. The language of the deaf is roughly based on this principle: performing a special set of gestures allows you to communicate without words.

Connection of functions with parts of the brain

What are cognitive functions based on their location in the brain? They are thought of as special areas of the brain with groups of neurons responsible for a specific type of nerve transmission. Impaired blood supply, damage or tumor growths in these areas lead to impairment of the cognitive functions of the brain.

Cognitive functions are formed in the cortex. It is divided into three zones:

• sensory – involved in processing signals from the senses;
• motor – provides movement of different parts of the body;
• associative – provides a connection between the two previous ones, determines a behavioral reaction based on impulses from the sensory zone.

The frontal lobes of the cortex provide logical, speech, and movement planning. Analysis centers are located in the parietal sensory sensations. Data processing visual analyzer conducts the occipital lobe, and the temporal lobe conducts hearing.

Older parts of the brain provide basic survival skills. The limbic system is memory, smell, emotions. The thalamus is responsible for redirecting impulses from the organs of hearing, vision, balance and tactile sense. Memorizing new information occurs thanks to the hippocampus.

The midbrain plays a role in consciousness and self-awareness, feelings of existence, and adaptive behavior. The interaction of all departments and the transmission of impulses occurs thanks to neurotransmitters:

• serotonin;
• dopamine;
• GABA;
• adrenalin;
• acetylcholine.

It often happens that they slow down or speed up cognitive tasks.

Reasons for violation

The severity of the disorders can vary: from mild to severe. Factors influencing the development of pathology are:

1. Degenerative diseases: , Parkinson's.
2. Pathologies associated with blood vessels: heart attack and stroke, atherosclerosis.
3. Metabolic disorders: hypoglycemia, hepatic or renal encephalopathy, drug use (benzodiazepines, anticholinergics), hypo- or hyperthyroidism.
4. Neuroinfections.
5. Head injuries.
6. Brain tumors.
7. Pathology of cerebrospinal fluid outflow.

The type of violation will depend on the location of the damaging factor. Mild or moderate cognitive impairment, even after a stroke in the elderly, can recover with proper treatment.

Cognitive functions: definition, impairment syndromes 2

Diagnosis of cognitive impairment 9

Treatment of cognitive disorders 13

Conclusion 19

Literature 20

Annex 1(neuropsychological tests) 26

Appendix 2(instructions for use of the drug Tanakan) 31

Management of patients with cognitive impairment.

V. V. Zakharov, A. B. Lokshina

Cognitive functions: definition, disorder syndromes.

The second half of the 20th century was characterized by significant changes in the age structure of the population, with a tendency towards an increase in the population of elderly and senile people. In 2000, there were about 400 million people in the world over the age of 65. It is expected that by 2025 this age group may increase to 800 million. These demographic trends increase the relevance of geriatric research. Today, doctors of various specialties need to know and take into account in their practice those physiological and psychological characteristics that characterize older people. Since age is the strongest and most independent risk factor for disorders of higher brain (cognitive) functions, the number of patients with these disorders is increasing simultaneously with the increase in the number of elderly people in the population.

Higher brain or cognitive functions (CF) include the most complex functions of the brain, with the help of which the process of rational cognition of the world is carried out and targeted interaction with it is ensured. Cognitive (cognitive) functions include:

- perception of information - gnosis;

- information processing and analysis – thinking, including the ability to generalize, identify similarities and differences, formal logical operations, establish associative connections, make inferences;

remembering and storing information – memory;

information exchange - speech

purposeful physical activity (praxis).

CF disorders significantly reduce the quality of life of patients and their relatives and are the cause of serious socio-economic losses suffered by society as a whole. According to statistics, up to one third of middle-aged people express dissatisfaction with their memory, and at least 50% of those over 65 years of age.

Cognitive impairment is a subjective and/or objective deterioration of higher brain functions compared to the initial more high level due to organic pathology of the brain, affecting the effectiveness of learning, professional, everyday and social activities. Cognitive impairments, along with other neurological disorders (motor, sensory, autonomic) are important and often the leading (and, in some cases, the only) manifestations of organic brain pathology. Essentially, any brain injury can cause cognitive impairment of varying severity.

When assessing cognitive disorders, as well as when analyzing other neurological disorders, it is important to determine their severity and qualitative characteristics, which depend primarily on the location of the brain lesion, the severity of development, dynamics, and connection with the state of other brain functions. Of great importance for nosological diagnosis, prognosis and therapeutic tactics is the assessment of the severity of cognitive impairment. According to the classification proposed by N.N. Yakhno, severe, moderate and mild cognitive impairment are distinguished.

Under severe cognitive impairment refers to persistent or transient disturbances of CF of various etiologies, which are so pronounced that they lead to difficulties in the patient’s usual everyday, professional and social activities. Severe cognitive impairments include dementia, delirium, severe aphasia, apraxia or agnosia, Wernicke-Korsakoff encephalopathy, etc. The most common type of severe cognitive impairment is dementia.

Dementia (dementia) is an acquired persistent impairment of CF as a result of an organic brain disease, manifested by disorders in two or more cognitive areas (memory, attention, speech, etc.) with normal consciousness and level of wakefulness, leading to difficulties in everyday life, social or professional life. patient activity.

At the stage of dementia, the patient completely or partially loses his independence and autonomy, and with moderate and severe dementia, he often needs outside care.

To diagnose dementia, the criteria most often used are the International Classification of Diseases, 10th revision (ICD-10) (Table 1) and DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th edition) (Table 2 ).

Dementia is a polyetiological syndrome that develops in various diseases of the brain. There are more than 100 diseases that are accompanied by dementia at one stage or another in the pathological process (Figure 1). However, the undisputed leaders in the list of causes of dementia in the elderly are Alzheimer's disease (AD),cerebrovascular insufficiency, mixed dementia (AD + cerebrovascular insufficiency) and dementia with Lewy bodies. These diseases underlie 75-80% of dementia in old age.

Figure 1. Most common reasons dementia

Dementia is the result of long-term progression of degenerative or vascular diseases of the brain. Moreover, in most cases, clinically defined symptoms are formed even before the onset of disturbances in daily activities, i.e., before the onset of dementia. In recent years, in the world literature, increasing attention has been paid to the problem of non-dementia forms of cognitive impairment in old age, which include mild and moderate cognitive impairment.

Moderate cognitive impairment (MCI) is an acquired impairment in one or more cognitive domains compared to a previous higher level as a result of an organic brain disease that goes beyond age norm, but not leading to loss of independence and independence in everyday life.

With MCI syndrome, there is no everyday, social and professional maladjustment. However, there may be difficulties in carrying out the most complex and unusual activities.

The prevalence of MCI in older age groups is very high and reaches 11-17% among people over 65 years of age. In a significant percentage of cases, MCI is progressive and eventually transforms into dementia. The incidence of only one form of dementia - AD - among elderly people with MCI reaches 10-15% per year, which is significantly higher than the statistical average (1-2%).

There are three main clinical variants of MCI syndrome:

amnestic variant(monofunctional variant of MCI with memory impairment). B clinical picture memory impairments for current events predominate, which are gradually progressive. This type of MCI usually transforms into AD over time.

MCI with multiple cognitive impairment(multifunctional variant of MCI). It is characterized by the presence of combined damage to several CFs: memory, spatial orientation, intelligence, praxis, etc. This type MCI may be noted on initial stages various brain diseases, for example, vascular brain failure, Parkinson's disease, frontotemporal dementia, etc.

MCI with impairment of one of the cognitive functions with intact memory(monofunctional variant of MCI without memory impairment) . Possible options of this syndrome with a predominance of speech or praxis disorders. This type of MCI syndrome can be observed in the early stages of neurodegenerative diseases such as primary progressive aphasia, corticobasal degeneration, dementia with Lewy bodies, etc.

Current diagnostic criteria for MCI syndrome are shown in Table 3.

Along with MCI syndrome, in our opinion, it is advisable to distinguish even milder cognitive impairments that are noted in the earliest stages of neurological diseases. Mild cognitive impairment (MCI) are predominantly neurodynamic in nature: such characteristics of cognitive processes as the speed of information processing, the ability to quickly switch from one type of activity to another are affected, RAM. At this stage, cognitive impairment does not interfere with professional and social activities, but can be identified based on the patient's subjective assessment and through in-depth neuropsychological testing.

Thus, mild cognitive impairment should be understood as a subjective and/or objective decrease in cognitive functions caused by age-related or pathological changes in the brain, which does not affect everyday, professional and social activities.

Our proposed diagnostic criteria for MCI are shown in Table 4.

As noted above, the causes of cognitive dysfunction in old age are diverse. It may be based on natural involutive changes in the brain associated with age, vascular and degenerative diseases of the brain. Emotional disorders, various somatic diseases, infectious, inflammatory diseases, traumatic brain injury, dysmetabolic disorders, brain tumors, etc. can contribute to the development of cognitive impairment. The main causes of cognitive impairment are shown in Table 5.

Diagnosis of cognitive impairment.

Both in Russia and in other countries of the world, there are several serious problems associated with insufficient diagnosis of cognitive impairment. This, firstly, is due to insufficient awareness of the population. Many people believe that a decline in memory and other cognitive functions is normal in old age. That is why patients and their relatives may not see a doctor until the stage of development of extremely severe disorders, when self-care skills are completely lost. Obviously, with such severity of disorders, the possibilities of helping patients are very limited. Meanwhile, at the present stage of development of medicine and pharmacology, therapy for cognitive impairment in the early stages of the development of the pathological process has a significant chance of success.

Another reason for the late diagnosis of cognitive impairment is insufficient knowledge by neurologists, psychiatrists, gerontologists and doctors of other specialties of methods for diagnosing this type of neurological disorder. Today, there is an obvious objective need for doctors of various specialties to master simple clinical and psychological research methods: the so-called dementia screening scales, which are listed in the Appendix. These scales are easy to use, take little time, and provide a quantitative assessment of the results obtained. The use of psychometric scales allows us to assess the dynamics of cognitive impairment, including during therapy. Dementia screening scales should be used in all patients complaining of memory impairment and decreased mental performance.