Symptoms of cognitive impairment

Symptoms of dementia are made up of cognitive, behavioral, emotional disorders and disturbances in daily activities.

Cognitive impairment is the clinical nucleus of any dementia. Cognitive impairment is the main symptom of this condition, therefore their presence is necessary for the diagnosis.

Cognitive functions (from English cognition - "cognition") - the most complex functions of the brain, through which a rational knowledge of the world and interaction with it. Synonyms for the term "cognitive functions" are "higher brain functions," "higher mental functions," or "cognitive functions."

Usually cognitive include the following functions of the brain.

• Memory is the ability to capture, save and repeatedly reproduce the information received.
• Perception (gnosis) is the ability to perceive and recognize information coming from outside.
• Psychomotor function (praxis) - the ability to compose, save and execute motor programs.
• Speech is the ability to understand and express your thoughts with words.
• Intelligence (thinking) - the ability to analyze information, generalize, identify similarities and differences, make judgments and conclusions, solve problems.
• Attention is the ability to distinguish the most important information from the general information flow, to concentrate on current activities, to support active mental work.
• Regulation of voluntary activity - the ability to arbitrarily choose the purpose of the activity, build a program to achieve this goal and monitor the implementation of this program at various stages of activity. Insufficient regulation leads to a reduction in initiative, stopping current activities, increased distraction. Such disorders are usually referred to as "dysregulatory disorders".

By definition, dementia is a polyfunctional disorder, therefore it is characterized by the simultaneous insufficiency of several or all cognitive abilities at once. However, various cognitive functions suffer in varying degrees - depending on the causes of dementia. Analysis of the characteristics of cognitive disorders plays an important role in establishing an accurate nosological diagnosis.

The most frequent form of cognitive disorders with dementia of different etiology is memory impairment. Expressed and progressive memory impairment, first to recent, and then to distant life events - the main symptom of Alzheimer's disease. Disease debuts with memory disorders, then they are joined by violations of spatial praxis and gnosis. Part of the patients, especially younger than 65-70 years, also develop speech disorders of the type of acoustic-mnestic aphasia. To a lesser degree, violations of attention and regulation of voluntary activity are expressed.

At the same time, violations of the regulation of voluntary activity become at the initial stages the main clinical characteristics of vascular dementia, dementia with Levi bodies, and diseases with a predominant lesion of the subcortical basal ganglia (Parkinson's disease, Huntington's disease, etc.). Disorders of spatial gnosis and praxis are also present, but they have a different nature and therefore do not lead, in particular, to disorientation on the terrain. Mark memory disorders, usually expressed in a moderate degree. Dysphagic disorders are not characteristic.

For frontotemporal lobar degeneration (frontal-temporal dementia), the most typical combination of disregulatory cognitive disorders and speech disorders is of the type of acoustic-mnestic and / or dynamic aphasia. At the same time, memory for life events remains safe for a long time.

With dismetabolic encephalopathy, the dynamic characteristics of cognitive activity suffer the most: the speed of reaction, the activity of mental processes, characterized by increased fatigue and distraction. Often this is combined with various disorders of the "sleep-wake" cycle.

Emotional disorders in dementias are most prevalent and expressed in the initial stages of the pathological process and gradually regress in the future. Emotional disorders in the form of depression occur in 25-50% of patients with the initial stages of Alzheimer's disease and in most cases of vascular dementia and diseases with a predominant lesion of the subcortical basal ganglia. Very disturbing disorders are also characteristic, especially in the early stages of Alzheimer's disease.

Behavioral disorders - a pathological change in the behavior of the patient, which causes concern to himself and / or those around him. Like emotional disorders, behavioral disorders are not necessary for diagnosing dementia, but they are very common (approximately 80% of patients). Behavioral disorders usually develop at the stage of mild or moderate dementia.

The most common behavioral disorders include the following.

• Apathy is the reduction of motivation and initiative, the absence or reduction of any productive activity of the patient.
• Irritability and aggression.
• Aimless motor activity - walking from corner to corner, vagrancy, shifting things from place to place, etc.
• Sleep disorders - daytime sleepiness and psychomotor agitation at night (the so-called sunset syndrome).
• Eating disorders - decreased or increased appetite, changes in eating habits (for example, increased cravings for sweets), giperoralizm (constant chewing, sucking, smacking, spitting, eating non-edible objects, etc.).
• Uncriticality is the loss of a sense of distance, indiscreet or tactless questions and comments, sexual incontinence.
• Delusions are persistent false conclusions. The most typical are delirium damage (relatives rob or plot something evil), jealousy, doubles (the spouse was replaced by a very similar ill-natured person), delusions like "I'm not at home".
• Hallucinations are more often visual, in the form of images of people or animals, less often auditory.

Disorders of daily activities are the integral result of cognitive and behavioral symptoms of dementia, as well as other neurological disorders associated with the underlying disease of the brain. The term "violation of daily activities" is understood as disorders of professional, social and everyday adaptation of the patient. The presence of violations of daily activities is indicated by the impossibility or significant difficulties at work, by interacting with other people, performing household duties, and in severe cases - in self-service. The presence of violations of daily activities indicates a greater or lesser loss of independence and independence for patients, with the need for outside help.

To the field of daily activity include the following activities:

• professional - the ability to effectively continue to perform their work;
• social - the ability to interact effectively with other people;
• instrumental - the ability to use household appliances;
• self-service - the ability to dress, perform hygienic procedures, eat food, etc.

The timing and sequence of occurrence of various symptoms of dementia are due to the nature of the underlying disease, but some of the most common patterns can be traced.

As a rule, dementia is preceded by the stage of mild cognitive impairment (MCI). Under moderate cognitive impairment, it is customary to understand the decline in cognitive abilities, which clearly exceeds the age limit, but does not significantly affect daily activity.

Modified diagnostic criteria for the syndrome of moderate cognitive impairment (Touchon J., Petersen R., 2004)

• Cognitive impairment according to the patient and / or his immediate environment (the latter is preferable).
• Signs of the recent deterioration of cognitive abilities compared to the individual norm for this person.
• Objective evidence of cognitive impairment, obtained with the help of neuropsychological tests (reduction of the results of neuropsychological tests by no less than 1.5 standard deviations from the average statistical norm).
• There are no violations of the daily activities typical for the patient, but there may be difficulties in complex activities.
• Dementia is absent - the result of a brief scale of assessment of mental status is not less than 24 points,

At the stage of moderate cognitive impairment, the patient complains of a memory impairment or a decrease in mental capacity for work. These complaints are confirmed by neuropsychological research: they reveal objective cognitive impairments. However, cognitive disorders at this stage are expressed to a small extent, so that they do not introduce a significant restriction of the daily activity usual for the patient. Difficulties in complex and unusual activities are possible, but patients with moderate cognitive impairment remain able to work, they are independent and independent in social life and everyday life, do not need outside help. Criticism to their condition is most often preserved, so patients, as a rule, are adequately alarmed by changes in their cognitive status. Often, moderate cognitive impairment is accompanied by emotional disorders in the form of anxiety and depression.

Progression of violations and the appearance of difficulties in the usual types of activities for the patient (normal work, interaction with others, etc.) indicate the formation of the syndrome of mild dementia. At this stage, patients are fully adapted within their apartment and the nearest area, but experience difficulties at work, when orienting in unfamiliar terrain, driving a car, performing calculations, making financial transactions and other complex activities. Orientation in place and time, as a rule, is preserved, but because of memory disorders, the exact date can be mistakenly determined. Part of the criticism for its condition is lost. The range of interests is narrowing, which is due to the inability to support more complex intellectually active activities. Behavioral disorders are often absent, while anxiety-depressive disorders are very common. Very characteristic is the sharpening of premorbid personality traits (for example, a thrifty person becomes greedy, etc.).

The emergence of difficulties within their own home is a sign of the transition to the stage of moderate dementia. First, there are difficulties in using household appliances (the so-called violations of the instrumental daily activities). Patients are trained to prepare food, use a TV, telephone, door lock, etc. There is a need for outside help: first only in individual situations, and then most of the time. In the stage of moderate dementia patients are usually disoriented in time, but are oriented in place and self. There is a significant reduction in criticism: patients in most cases deny the presence of any memory impairment or other higher brain functions. Behavioral disorders that are capable of reaching considerable levels of severity: irritability, aggression, delusions, inadequate motor behavior, etc. Are very characteristic (but not necessary). As the pathological process progresses further, difficulties arise in self-service (dressing, performing hygienic procedures).

Severe dementia is characterized by the almost complete helplessness of the patient in most everyday situations, which necessitates constant external help. At this stage, nonsense and other behavioral disorders gradually regress, which is associated with an increasing intellectual insufficiency. Patients are disoriented in place and time, there are pronounced violations of praxis, gnosis and speech. Significant severity of cognitive disorders makes differential diagnosis between different nosological forms of dementia very difficult at this stage. Neurological disorders such as gait and pelvic disorders are associated. The final stages of dementia are characterized by loss of speech, inability to walk independently, urinary incontinence and neurological symptoms of decortication.

The main stages of dementia development:

• moderate cognitive impairment;
• violation of professional and social activities;
• reduction of criticism, personality change;
• violation of instrumental daily activities;
• formation of behavioral disorders;
• violation of self-service;
• loss of speech, pelvic disorders, urinary incontinence;
• decortication.

Characteristics of the main stages of cognitive deficits

Stage	Cognitive functions	Emotional and behavioral disorders	Daily Activity
Moderate cognitive impairment	Violent violations with strong criticism	Anxiety-depressive disorders	Not violated
Mild dementia	Expressed violations with reduced criticism	Anxious and depressive disorders. Personality changes	Violated professional and social activity. At home, the patient is independent
Moderate dementia	Expressed violations with reduced criticism. Disorientation in time	Delirium, aggression, aimless motor activity, sleep and appetite disorders, faux pas	The instrumental daily activity is disrupted. Sometimes he needs help
Severe dementia	Rough violations. Disorientation in place and time	Regress delirium, lack of initiative	Interruption of self-service. Constantly in need of help

[1], [2], [3], [4]