A study of cognitive function

In the clinical practice of a neurologist, the assessment of cognitive functions includes the study of orientation, attention, memory, counting, speech, writing, reading, praxis, and gnosis.

Orientation

The study of the patient's ability to navigate his own personality, place, time and current situation is carried out in parallel with an assessment of his state of consciousness.

• Orientation to one's own personality: the patient is asked to state his name, address of residence, profession, and marital status.
• Orientation to the place: ask the patient to say where he is now (city, name of the medical institution, floor) and how he arrived here (by transport, on foot).
• Orientation in time: ask the patient to name the current date (day, month, year), day of the week, time. You can ask the date of the nearest upcoming or past holiday.

Further examination of the patient's mental functions is carried out if it is established that he is in a clear consciousness and is able to understand instructions and questions asked of him.

Attention

Human attention is understood as both the ability to comprehend many aspects of stimulating effects at any given moment in time, and a non-specific factor ensuring selectivity, selectivity of the flow of all mental processes as a whole. Neurologists often use this term to denote the ability to focus on certain sensory stimuli, distinguishing them from others. It is customary to distinguish between fixation of attention, switching attention from one stimulus to another, and maintaining attention (necessary to complete a task without signs of fatigue). These processes can be voluntary and involuntary.

The ability to concentrate and hold attention is severely impaired in states of acute confusion, suffers to a lesser extent in dementia, and is generally not impaired in focal brain lesions. Concentration is tested by asking the patient to repeat a series of numbers or to cross out a certain letter for some time, which is written on a piece of paper in random alternation with other letters (the so-called proofreading test). Normally, the subject correctly repeats 5-7 numbers after the researcher and crosses out the desired letter without errors. In addition, to assess attention, the patient can be asked to count to ten in forward and backward order; list the days of the week, months of the year in forward and backward order; arrange the letters that make up the word "fish" in alphabetical order or pronounce this word by sounds in reverse order; report when the required sound is found among the sounds named in random order, etc.

Read also: Attention Deficit Disorder

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Memory

The term “ memory ” refers to the process of cognitive activity, which includes three components: acquisition and coding (memorization) of information; its storage (retention) and reproduction (retrieval).

In accordance with the concept of the temporary organization of memory, the following types are distinguished: immediate (instantaneous, sensory), short-term (working) and long-term.

• Tests assessing immediate memory are similar to tests assessing attention and involve the patient immediately recalling a series of numbers or words that the subject has not previously learned. For example, the patient may be asked to repeat the following series of numbers after the examiner (say them slowly and clearly): 4-7-9, 5-8-2-1, 9-2-6-8-3, 7-5-1-9-4-6, 1-8-5-9-3-6-7, 9-3-8-2-5-1-4-7. The patient is then asked to repeat the series of numbers, saying them in the reverse order in which they were previously said. Normally, a healthy adult of average intelligence can easily recall a series of seven numbers in a forward sequence and five numbers in a reverse order. The patient may also be asked to name three objects that are not logically related to each other (e.g., "table-road-lamp") and asked to immediately repeat these words.
• To assess short-term memory, the patient's ability to learn new material and recall recently learned information is examined. Verbal and non-verbal (visual) memory is tested using the following tests.
  • The subject is asked to list what he ate for breakfast.
  • They tell the patient their first and middle name (if he didn’t know them before) and after a while ask him to repeat it.
  • The patient is told three simple words (for example, denoting a name, time of day, item of clothing) and immediately asked to repeat them. If the patient makes a mistake, attempts are repeated until he or she correctly names all three words (the number of attempts is recorded). After 3 minutes, the subject is asked to recall these three words.
  • The patient is asked to remember a sentence. The phrase is read aloud slowly and clearly and the patient is asked to repeat it. If he makes a mistake, the attempts are repeated until the patient copes with the task. The number of attempts is recorded. The patient can also be asked to reproduce short phrases added by the doctor (the patient repeats them aloud, starting with the first, then the second and subsequent ones, for example: "One special original"; "Two kind wild porcupines"; "Three fat quiet tarantulas"; "Four turtles scratched the skull of an eccentric"; "Five quails sang pleasantly, having eaten a hearty dinner." If the patient repeated the first four phrases without errors, then the memory can be considered good.
  • The patient is shown a picture of several objects and asked to remember them; then, after removing the picture, they are asked to list these objects and the number of errors is noted. It is also possible to show a picture of a number of objects and then ask the subject to find these objects in another set of images.
• Long-term memory is assessed by asking the patient about autobiographical, historical, and cultural events (specific questions depend on the patient's supposed level of education). For example, you can ask him to name his date and place of birth; place of study; name of his first teacher; date of marriage; names of parents, spouse, children, and their birthdays; name of the country's president; well-known historical dates (the beginning and end of the Great Patriotic War); names of major rivers and cities in Russia.

Read also: Memory impairment

Check

Disorders of counting and counting operations that occur in patients with organic brain damage are called "acalculia". Primary (specific) acalculia occurs in the absence of other disorders of higher brain functions and is manifested by a disorder of ideas about numbers, their internal composition and digit structure. Secondary (non-specific) acalculia is associated with primary disorders of recognizing words denoting numbers and figures, or with a disordered development of an action program.

Assessment of numeracy in clinical neurological practice is most often limited to tasks involving performing arithmetic operations and solving simple arithmetic problems.

• Serial Counting: The patient is asked to perform a serial subtraction of seven from 100 (subtract seven from 100, then successively subtract seven from the remainder 3-5 more times) or three from 30. The number of errors and the time required for the patient to complete the task are noted. Errors in completing the test can be observed not only in acalculia, but also in concentration disorders, as well as in apathy or depression.
• If the patient has cognitive impairments when solving the above-mentioned problems, he is offered simple problems on addition, subtraction, multiplication, division. It is also possible to offer solutions to everyday problems with arithmetic operations: for example, to calculate how many pears can be bought for 10 rubles if one pear costs 3 rubles, how much change will be left, etc.

Ability to generalize and abstract

The ability to compare, generalize, abstract, form judgments, and plan refers to the so-called "executive" mental functions of a person associated with the voluntary regulation of all other areas of mental activity and behavior. Various disorders of executive functions (for example, impulsivity, limited abstract thinking, etc.) in a mild form are possible in healthy individuals as well, therefore, the main importance in diagnostics is given not to determining the type of disorders of executive functions, but to assessing their severity. In neurological practice, only the simplest tests are used to assess executive functions. During the examination, it is important to obtain information about the premorbid characteristics of the patient. The patient is asked to explain the meaning of several well-known metaphors and proverbs ("golden hands", "don't spit in the well", "the slower you go, the further you will get", "wolf appetite", "a bee flies from a wax cell for a field tribute", etc.), to find similarities and differences between objects (an apple and an orange, a horse and a dog, a river and a canal, etc.).

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Speech

When talking to a patient, they analyze how he understands the speech addressed to him (sensory part of speech) and reproduces it (motor part of speech). Speech disorders are one of the complex problems of clinical neurology, it is studied not only by neurologists, but also by neuropsychologists, speech therapists. Below we consider only the main issues of speech disorders, helping topical diagnostics.

Speech may suffer relatively isolated from other higher brain functions in focal lesions of the brain or simultaneously with other disorders in the cognitive sphere in dementias. Aphasia is a disorder of already formed speech that occurs in focal lesions of the cortex and adjacent subcortical region of the dominant hemisphere (left in right-handers) and is a systemic disorder of various forms of speech activity with preservation of elementary forms of hearing and movements of the speech apparatus (i.e. without paresis of the speech muscles - lingual, laryngeal, respiratory muscles).

Classical motor aphasia (Broca's aphasia) occurs when the posterior sections of the inferior frontal gyrus of the dominant hemisphere are affected, and sensory aphasia (Wernicke's aphasia) occurs when the middle and posterior sections of the superior temporal gyrus of the dominant hemisphere are affected. In motor aphasia, all types of oral speech (spontaneous speech, repetition, automated speech) are impaired, as well as writing, but the understanding of oral and written speech is relatively intact. In Wernicke's sensory aphasia, both the understanding of oral and written speech and the patient's own oral and written speech are impaired.

In neurological practice, speech disorders are diagnosed by assessing spontaneous and automated speech, repetition, naming objects, speech comprehension, reading and writing. These studies are conducted on patients with speech disorders. When examining a patient, it is important to determine the dominance of his hemispheres, that is, to find out whether he is right-handed or left-handed. Here it can be mentioned that, according to neurophysiologists, the left hemisphere provides the functions of abstract thinking, speech, logical and analytical functions mediated by the word. People in whom the functions of the left hemisphere prevail (right-handed) are drawn to theory, purposeful, able to predict events, motor active. In patients with functional dominance of the right hemisphere of the brain (left-handed), concrete thinking, slowness and taciturnity, a tendency to contemplation and memories, emotional coloring of speech, and musical ear prevail. The following tests are used to determine the dominance of the hemisphere: determining the dominant eye with binocular vision, clasping the hands together, determining the strength of clenching a fist with a dynamometer, folding the arms on the chest (the "Napoleon pose"), applauding, pushing leg, etc. In right-handed people, the dominant eye is the right, the thumb of the right hand is on top when clasping the hands together, the right hand is stronger, it is also more active when applauding, when folding the hands on the chest, the right forearm is on top, the right leg is the pushing leg, and in left-handed people, everything is the opposite. Often, a convergence of the functional capabilities of the right and left hands is observed (ambidexterity).

• Spontaneous speech is examined when meeting the patient, asking him questions: “What is your name?”, “What do you do for a living?”, “What is bothering you?”, etc. It is necessary to pay attention to the following disorders.
  • Changes in the speed and rhythm of speech, which manifests itself in slowing down, intermittent speech, or, on the contrary, in its acceleration and difficulty stopping.
  • Disturbances in the melody of speech (dysprosody): it can be monotonous, inexpressive, or acquire a “pseudo-foreign” accent.
  • Speech suppression (complete absence of speech production and attempts at verbal communication).
  • The presence of automatisms (“verbal emboli”) - frequently, involuntarily and inappropriately used simple words or expressions (exclamations, greetings, names, etc.), which are the most resistant to elimination.
• Perseverations (“getting stuck”, repetition of a syllable or word that has already been pronounced, which occurs when attempting verbal communication).
• Difficulty in finding words when naming objects. The patient's speech is hesitant, full of pauses, contains many descriptive phrases and words of a substitutive nature (like "well, how is it there...").
• Paraphasias, i.e. errors in pronouncing words. There are phonetic paraphasias (inadequate production of phonemes of the language due to simplification of articulatory movements: for example, instead of the word "store" the patient pronounces "zizimin"); literal paraphasias (replacement of some sounds with others, similar in sound or place of origin, for example "bump" - "bud"); verbal paraphasias (replacement of one word in a sentence with another, reminiscent of it in meaning).
• Neologisms (linguistic formations used by the patient as words, although there are no such words in the language he speaks).
• Agrammatisms and paragrammatisms. Agrammatisms are violations of grammar rules in a sentence. The words in a sentence do not agree with each other, syntactic structures (auxiliary words, conjunctions, etc.) are shortened and simplified, but the general meaning of the message being conveyed remains clear. With paragrammatisms, the words in a sentence formally agree correctly, there are enough syntactic structures, but the general meaning of the sentence does not reflect the real relationships between things and events (for example, "Hay dries peasants in June"), as a result, it is impossible to understand the information being conveyed.
• Echolalia (spontaneous repetition of words or combinations of words spoken by the doctor).
• To assess automated speech, the patient is asked to count from one to ten, list the days of the week, months, etc.
  • To assess the ability to repeat speech, the patient is asked to repeat after the doctor vowels and consonants (a, o, i, y, b, d, k, s, etc.), oppositional phonemes (labial - b/p, anterior lingual - t/d, z/s), words (house, window, cat; groan, elephant; colonel, admirer, ladle; shipwreck, cooperative, etc.), series of words (house, forest, oak; pencil, bread, tree), phrases (a girl is drinking tea; a boy is playing), tongue twisters (there is grass in the yard, there is firewood on the grass).
  • The ability to name objects is assessed after the patient names the objects shown to him (watch, pen, tuning fork, flashlight, piece of paper, body parts).
• The following tests are used to assess understanding of oral speech.
  • Understanding the meaning of words: they name an object (hammer, window, door) and ask the patient to point it out in the room or in a picture.
  • Understanding verbal instructions: the patient is asked to perform one-, two-, and three-component tasks in sequence ("Show me your left hand," "Raise your left hand and touch your right ear with the fingers of this hand," "Raise your left hand, touch your right ear with the fingers of this hand, and stick out your tongue at the same time"). Instructions should not be reinforced with facial expressions and gestures. The correct execution of commands is assessed. If the subject has difficulties, the instructions are repeated, accompanied by facial expressions and gestures.
  • Understanding logical and grammatical structures: the patient is asked to follow a series of instructions containing genitive case constructions, comparative and reflexive forms of verbs or spatial adverbs and prepositions: for example, show a key with a pencil, a pencil with a key; put a book under a notebook, a notebook under a book; show which object is lighter and which is lighter; explain who is referred to in the expressions "mama's daughter" and "dochkina mama", etc.
• To assess the writing function, the patient is asked (having provided him with a pen and a sheet of paper) to write his name and address, then write down several simple words ("cat", "house"); a sentence ("A girl and a boy are playing with a dog") from dictation and copy the text from a sample printed on paper. In most cases, patients with aphasia also suffer from writing (i.e., agraphia is present - the loss of the ability to write correctly while maintaining the motor function of the hand). If the patient can write but does not speak, he most likely has mutism, but not aphasia. Mutism can develop in a wide variety of diseases: with severe spasticity, paralysis of the vocal cords, bilateral damage to the corticobulbar tracts, and is also possible in mental illnesses (hysteria, schizophrenia ).
• To assess reading, the patient is asked to read a paragraph from a book or newspaper, or to read and follow instructions written on paper (for example, “Go to the door, knock on it three times, come back”), and then assess the correctness of its implementation.

For neurological diagnostics, it is very important to be able to distinguish motor aphasia from dysarthria, which is typical for bilateral lesions of the corticonuclear tracts or nuclei of the cranial nerves of the bulbar group. With dysarthria, patients say everything, but pronounce words poorly, especially difficult to articulate are the speech sounds "r", "l", and hissing sounds. Sentence construction and vocabulary are not affected. With motor aphasia, the construction of phrases and words is impaired, but at the same time the articulation of individual articulate sounds is clear. Aphasia also differs from alalia - underdevelopment of all forms of speech activity, manifested by speech impairment in childhood. The most important signs of various aphasic disorders are summarized below.

• In motor aphasia, patients generally understand other people's speech, but have difficulty choosing words to express their thoughts and feelings. Their vocabulary is very poor, and may be limited to just a few words ("embolic words"). When speaking, patients make mistakes - literal and verbal paraphasias, try to correct them, and often get angry with themselves for not being able to speak correctly.
• The main signs of sensory aphasia include difficulties in understanding other people's speech and poor auditory control of one's own speech. Patients make many literal and verbal paraphasias (sound and word errors), do not notice them and get angry with the interlocutor who does not understand them. In severe forms of sensory aphasia, patients are usually verbose, but their statements are not very clear to others ("speech salad"). To identify sensory aphasia, you can use the Marie experiment (the patient is given three sheets of paper and asked to throw one of them on the floor, put another on the bed or table, and return the third to the doctor) or Ged's experiment (the patient is asked to put a large coin in a small cup, and a small one in a large one; the experiment can be complicated by placing four different cups, the same number of coins of different sizes and asking the patient to place them).
• With foci at the junction of the temporal, parietal and occipital lobes, one of the variants of sensory aphasia may arise - the so-called semantic aphasia, in which patients do not understand the meaning of individual words, but the grammatical and semantic connections between them. Such patients cannot, for example, distinguish between the expressions "father's brother" and "brother's father" or "the cat ate the mouse" and "the cat was eaten by the mouse."
• Many authors distinguish another type of aphasia - amnestic, in which patients find it difficult to name various objects shown, forgetting their names, although they can use these terms in spontaneous speech. Usually such patients are helped if they are prompted with the first syllable of the word denoting the name of the object shown. Amnestic speech disorders are possible with different types of aphasia, but most often they occur with damage to the temporal lobe or parietal-occipital region. Amnestic aphasia should be distinguished from a broader concept - amnesia, that is, a memory disorder for previously developed ideas and concepts.

Praxis

Praxis is understood as the ability to perform sequential sets of conscious voluntary movements to perform purposeful actions according to a plan developed through individual practice. Apraxia is characterized by the loss of skills developed through individual experience, complex purposeful actions (everyday, industrial, symbolic gesticulation, etc.) without pronounced signs of central paresis or movement coordination disorders. Depending on the localization of the lesion, several types of apraxia are distinguished.

• Motor (kinetic, efferent) apraxia is manifested by the fact that the sequential switching of movements is disrupted and disorders of the formation of motor links that form the basis of motor skills occur. A characteristic disorder of smoothness of movements, "getting stuck" on individual fragments of movements and actions (motor perseverations). Observed with a lesion in the lower sections of the premotor region of the frontal lobe of the left (in right-handed people) hemisphere (with damage to the precentral gyrus, central paresis or paralysis develops, in which apraxia cannot be detected). To detect motor apraxia, the patient is asked to perform the "fist-edge-palm" test, that is, to hit the surface of the table with a fist, then with the edge of the palm, and then with the palm with straightened fingers. This series of movements is asked to repeat at a fairly fast pace. A patient with damage to the premotor region of the frontal lobe experiences difficulties in performing such a task (loses the sequence of movements, cannot perform the task at a fast pace).
• Ideomotor (kinesthetic, afferent) apraxia occurs when the inferior parietal lobe is damaged in the area of the supramarginal gyrus, which is classified as a secondary field of the kinesthetic analyzer cortex. In this case, the hand does not receive afferent feedback signals and is unable to perform fine movements (at the same time, a lesion in the area of the primary fields of the postcentral gyrus causes a gross disturbance of sensitivity and afferent paresis, in which the ability to control the opposite hand is completely lost, but this disorder is not classified as apraxia). Apraxia is manifested by a disturbance of fine differentiated movements on the side opposite to the lesion: the hand cannot assume the pose necessary to perform a voluntary movement, adapt to the nature of the object with which the specified manipulations are performed (the "spade hand" phenomenon). The search for the necessary pose and errors are characteristic, especially if there is no visual control. Kinesthetic apraxia is revealed when performing simple movements (both with real objects and when imitating these actions). To reveal it, you should ask the patient to stick out his tongue, whistle, show how to light a match (pour water into a glass, use a hammer, hold a pen to write with it, etc.), dial a phone number, comb his hair. You can also ask him to close his eyes; fold his fingers into some simple figure (for example, "goat"), then destroy this figure and ask him to restore it independently.
• Constructive apraxia (spatial apraxia, apractognosia) is manifested by a violation of the coordination of joint hand movements, difficulty in performing spatially oriented actions (difficulty making the bed, getting dressed, etc.). There is no clear difference between performing movements with open and closed eyes. Constructive apraxia, which is manifested in the difficulty of constructing a whole from individual elements, also belongs to this type of disorder. Spatial apraxia occurs when the lesion is localized in the junction of the parietal, temporal and occipital regions (in the angular gyrus of the parietal lobe) of the cortex of the left (in right-handers) or both hemispheres of the brain. When this zone is damaged, the synthesis of visual, vestibular and cutaneous-kinesthetic information is disrupted and the analysis of action coordinates is impaired. Tests that reveal constructive apraxia include copying geometric figures, drawing a clock face with the arrangement of numbers and hands, and building structures from cubes. The patient is asked to draw a three-dimensional geometric figure (e.g., a cube); copy a geometric figure; draw a circle and arrange the numbers in it as on a clock face. If the patient has completed the task, he is asked to arrange the hands so that they show a certain time (e.g., "a quarter to four").
• Regulatory ("prefrontal", ideational) apraxia includes disorders of voluntary regulation of activity directly related to the motor sphere. Regulatory apraxia is manifested in the fact that the execution of complex movements is impaired, including the execution of a series of simple actions, although the patient can perform each of them separately correctly. The ability to imitate is also preserved (the patient can repeat the doctor's actions). At the same time, the patient is unable to make a plan of sequential steps necessary to perform a complex action, and is unable to control its implementation. The greatest difficulty is simulating actions with absent objects. For example, a patient finds it difficult to show how to stir sugar in a glass of tea, how to use a hammer, comb, etc., while he performs all these automatic actions with real objects correctly. Starting to perform an action, the patient switches to random operations, getting stuck on fragments of the started activity. Echopraxia, perseverations and stereotypies are characteristic. Patients are also distinguished by excessive impulsiveness of reactions. Regulatory apraxia occurs when the prefrontal cortex of the frontal lobe of the dominant hemisphere is damaged. To identify it, patients are asked to take a match out of a matchbox, light it, then put it out and put it back in the box; open a tube of toothpaste, squeeze a column of paste onto a toothbrush, and screw the cap on the tube of toothpaste.

Gnosis

Agnosia is a disorder of recognizing objects (items, faces) while preserving elementary forms of sensitivity, vision, and hearing. There are several types of agnosia - visual, auditory, olfactory, etc. (depending on which analyzer the disorder occurred). In clinical practice, optical-spatial agnosia and autotopagnosia are most often observed.

• Optospatial agnosia is a disorder of the ability to perceive spatial features of the environment and images of objects ("farther-closer", "bigger-smaller", "left-right", "top-bottom") and the ability to navigate in external three-dimensional space. It develops with damage to the superior parietal or parietal-occipital regions of both hemispheres or the right hemisphere of the brain. To identify this form of agnosia, the patient is asked to draw a map of the country (in an approximate version). If he cannot do this, they draw the map themselves and ask them to mark the location of five large, not well-known cities on it. The patient can also be asked to describe the route from home to the hospital. A manifestation of opto-spatial agnosia is considered to be the phenomenon of ignoring one half of the space (unilateral visual-spatial agnosia, unilateral spatial neglect, hemispatial neglect, hemispatial sensory inattention). This syndrome manifests itself in difficulty in perceiving (ignoring) information coming from one hemisphere of the surrounding space, in the absence of primary sensory or motor deficit in the patient, including hemianopsia. For example, the patient eats only the food that is on the right side of the plate. The phenomenon of ignoring is associated mainly with damage to the parietal lobe, although it is also possible with temporal, frontal and subcortical localization of the pathological process. The phenomenon of ignoring the left half of space is most common with damage to the right hemisphere of the brain. The following tests are used to identify the syndrome of ignoring (it should be emphasized that they are applicable only if the patient does not have hemianopsia).
  • The patient is given a lined notebook sheet and asked to divide each line in half. In the case of neglect syndrome, a right-handed person will place marks not in the middle of the lines, but at a distance of three-quarters from its left edge (that is, he divides only the right half of the lines in half, ignoring the left).
  • The patient is asked to read a paragraph from a book. If there is ignoring, he can only read the text located on the right half of the page.
• Autotopagnosia (asomatognosia, body scheme agnosia) is a disorder of recognizing parts of one's body and their location in relation to each other. Its variants include finger agnosia and disorder of recognizing the right and left halves of the body. The patient forgets to put clothes on the left limbs and wash the left side of the body. The syndrome most often develops with damage to the upper-parietal and parietal-occipital regions of one (usually the right) or both hemispheres. To detect autotopagnosia, the patient is asked to show the thumb of the right hand, the index finger of the left hand, touch the left ear with the right index finger, and touch the right eyebrow with the index finger of the left hand.