Cognitive impairment

Cognitive impairment

Dementia (from Latin de - "loss", mentos - "mind", synonym - dementia) - acquired stable polyfunctional cognitive impairment (impairment of memory, intelligence, mental performance, etc.), expressed to a large extent, determined against a background of clear consciousness , causing organic damage to the brain.

The acquired nature of cognitive impairment in dementia indicates that this condition develops as a result of any brain injury that has occurred during life. Dementia is a decrease in intelligence compared with the initially higher level. This dementia differs from the initial underdevelopment of cognitive functions (oligophrenia).

Stability violations imply that they are present for a certain long time. Thus, according to the recommendations of the International Classification of Diseases of the Tenth Revision (ICD-10), the diagnosis of "dementia" is valid with a duration of cognitive disorders of at least 6 months. Before this time the diagnosis can be formulated presumably.

Polyfunctional nature of violations implies the simultaneous suffering of several cognitive functions, for example, memory and speech, memory and intelligence or memory, intelligence and speech, etc. In this case, the violation of each cognitive function is expressed to a large extent.

A significant degree of violations implies the fact that they have a negative impact on everyday life, that is, cause difficulties in at least one of the following areas: professional activity, hobbies and hobbies, interaction with other people, everyday life, self-service. In the absence of such difficulties, one should not speak of dementia, but of non-essential (light or moderate) cognitive impairments.

Cognitive disorders in dementia are revealed against a background of clear consciousness, that is, they are not related to the confusion of consciousness. A patient with dementia demonstrates memory and attention disorders, being in a state of active wakefulness. This dementia differs from delirium.

By definition, the underlying cause of dementia is always organic damage to the brain. It is important to note that it is not always primary, that is, it is not always associated with direct anatomical damage to the cerebral structures. The brain can suffer again in relation to somatic pathology. Pathogenetic mechanisms of damage in such cases are systemic dysmetabolic disorders (the so-called dismetabolic encephalopathy, for example, in hypothyroidism).

It should be noted that severe depression sometimes leads to severe cognitive impairment in the absence of organic brain damage. The terms "pseudodementia" and "depressive pseudodement" are used to denote such states.

Epidemiology of cognitive impairment

The prevalence of dementia is at least 5% among people over 65 years of age and increases many times in older age groups. In 2006, 21 million patients with dementia were officially registered in the world.

Classification of cognitive impairment

By severity, cognitive impairment is divided into mild, moderate and severe. Dementia is one of the types of severe cognitive impairment.

• Severe people consider disorders of cognitive functions that limit daily activities and lead to partial or complete loss of independence and independence of the patient. In addition to dementia, severe cognitive disorders are noted in delirium (often transient) and depressive pseudodementia. Severe cognitive impairment should also include severe monofunctional disorders, for example, coarse aphasia, apraxia and others, which limit daily activities.
• Moderate cognitive impairment is a mono- or polyfunctional defect, subjectively perceived and attracting the attention of others, but not causing a patient's disadaptation, that is, loss of independence and independence. In this case, the patient may experience difficulties in complex and unusual for him activities. In more than half of cases, moderate cognitive impairments are transformed into dementia over time. Thus, this syndrome is usually noted in the pre-existing stages of progressive brain diseases.
• Light cognitive impairment is a subjective and / or objective decrease in cognitive abilities in comparison with the individual baseline level, which does not cause any difficulties in daily activity, including in its most complex forms. Light cognitive impairment does not always represent a pathological symptom. In some cases, they may be the result of natural age-related involuntary changes in the brain (so-called age-related memory impairment, or age-related cognitive impairment).

Symptoms of cognitive impairment

The clinical picture of dementia is 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.

Symptoms of cognitive impairment

The causes of cognitive impairment

Dementia is a polyethological syndrome that develops in various brain diseases. There are several dozens of nosological forms within which dementia syndrome can develop. The most common of these are Alzheimer's disease, dementia with Levy bodies, cerebral vascular insufficiency, frontotemporal degeneration, diseases with predominant lesion of subcortical basal ganglia ("subcortical dementias"). These nosological forms respond not less than 80% of dementia in old age.

Causes of cognitive impairment

Diagnosis of cognitive impairment

The first stage of the diagnosis of dementia is to identify cognitive impairment and assess their severity (syndromic diagnosis). For the study of cognitive functions, clinical methods (collection of complaints, anamnesis of the patient) and neuropsychological tests are used. Ideally, every patient with cognitive complaints should undergo a detailed neuropsychological study, but in practice this is hardly possible. Therefore, neurologists, psychiatrists and doctors of other specialties are recommended to use the so-called screening scales of dementia, which take relatively little time and are quite simple in carrying out and interpreting. Most often use a short scale of assessment of mental status and a test drawing hours.

Diagnosis of cognitive impairment

A echenie dementia and other cognitive impairment

The choice of therapeutic tactics depends on the cause (nosological diagnosis) and the severity of cognitive impairment. In the stage of mild and moderate dementia associated with Alzheimer's disease, vascular and mixed (vascular degenerative) dementia, dementia with Lewy bodies and Parkinson's disease with dementia, acetylcholinergic and glutamatergic drugs have proved themselves.

Currently, 4 drugs from the group of acetylcholinesterase inhibitors are used in the therapy of dementia: donepezil, rivastigmine, galantamine and ipidacrin. The use of these drugs helps to reduce the severity of cognitive impairment, normalize behavior, increase adaptation in everyday life, which ultimately leads to an improvement in the quality of life of patients and their immediate environment.

Another approach to the pathogenetic therapy of dementia is the use of memantine, a reversible non-competitive blocker of N-methyl-O-aspartate receptors for glutamate. It is used for the same diseases as acetylcholinesterase inhibitors. In severe dementia memantine is the first choice drug, as the effectiveness of acetylcholinergic drugs in this stage is not well understood. Contraindications to the appointment of memantine - epilepsy and renal failure. Side effects are extremely rare.

Treatment of dementia and cognitive impairment

[1], [2], [3], [4], [5], [6], [7], [8], [9], [10]