Symptoms of dementia

Dementia can manifest itself as increased forgetfulness, personality changes, decreased initiative, weakened critical thinking, difficulty performing routine tasks, difficulty finding words, impaired abstract thinking, behavioral and mood disorders. “Non-cognitive” manifestations of dementia include sleep disorders, wandering, depression, psychosis, and other behavioral disorders. “Non-cognitive” symptoms of dementia often disrupt the patient’s life and are the main reason for seeking medical attention.

If dementia is suspected, the anamnesis should be collected from both the patient and those who are well informed about the patient. In the early stages, the doctor's main attention should be directed to identifying any difficulties in the patient's daily activities, since this is where the first signs of mental insolvency usually appear and therefore it is noticed earlier by attentive relatives, and not by doctors.

The earliest and most constant sign of dementia is a disorder of short-term memory. Forgetfulness of instructions and assignments, a growing tendency to misplace things, small inconsistencies in some seemingly ordinary actions - all these behavioral features are noticed first of all by loved ones. Difficulty in counting (for example, money), inability to use household appliances (for example, a telephone) or other difficulties in work or home activities that were previously completely unusual for this patient appear. As dementia progresses, a narrowing of the range of interests, a decrease in activity, an increasing deterioration in memory, a decrease in criticism are noted. The patient may experience difficulties in trying to find his way to a known place, revealing partial disorientation in place and time. Deceptions of the senses, hallucinations, a decrease in control of behavior may appear, which is manifested by episodes of excitement and impulsive behavior. This explains acts of violence, alcoholic excesses, sexual deviations, antisocial behavior. Patients become careless in their clothes and unkempt; in the final stage, urinary incontinence develops. Motor and speech perseverations appear. Speech sometimes undergoes progressive disintegration. Any form of aphasia may develop, often accompanied by agnosia and apraxia. Gait is disturbed - dysbasia. In severe cases - amnestic disorientation in space, time, the surrounding environment, in one's own personality (the patient does not recognize himself in the mirror), mutism.

The presence or absence of somatic manifestations depends on the etiology of dementia, but in any case, general physical exhaustion, weight loss, and suppression of endocrine functions are observed. Dementia can reach the final stage of disintegration of mental functions - the stage of marasmus. The patient spends most of the time in bed and dies of pneumonia or other intercurrent diseases.

It is important to remember that there are two important limitations in the clinical diagnosis of dementia. First, the diagnosis of dementia should not be made if the patient is in a clouded state of consciousness. In other words, it is necessary to be sure that the deterioration of mental functions is not due to a disturbance of consciousness. Second, the term "dementia" does not apply to individual failures of complex brain functions, such as amnesia, aphasia, agnosia or apraxia. Although dementia may well be combined with these syndromes.

Dementia is always a syndrome, not a disease. Differential diagnosis of the causes of dementia, which always indicates organic damage to the brain, is difficult due to the very large number of diseases that can lead to the development of dementia. For successful orientation in the range of these diseases, a convenient diagnostic algorithm is proposed, according to which a differential diagnosis is first carried out between three groups of diseases. We are talking about depression, toxic-metabolic encephalopathies and brain diseases proper. At the second stage, the diagnostic search is significantly narrowed, which significantly facilitates differential diagnosis.

Clinical experience suggests that depression is sometimes mistakenly interpreted as dementia. This is due to the fact that depression, accompanied by memory loss, attention deficit, narrowing of interests and motivations, can resemble dementia. Here, everyday activities are also difficult, which together can serve as a reason for suspecting dementia. This form of depression is called pseudodementia and is subject to reverse development under the influence of antidepressants.

Another diagnostic alternative in the presence of dementia is toxic-metabolic encephalopathy. Many possible causes (drug intoxication, organ failure) require screening for metabolic disorders. In addition to knowing the clinical picture, it is important to remember two important, but often underestimated, markers of toxic-metabolic encephalopathy. Firstly, transient states of confusion are very typical for the latter. Sometimes confusion develops as an initial manifestation of dysmetabolic encephalopathy. Secondly, another important marker concerns the EEG picture in these diseases. According to many experts, if the EEG does not show signs of slowing down of bioelectrical activity, i.e. a shift in the wave spectrum towards a decrease in normal alpha activity and an increase in the representation of slow waves (theta and delta ranges), then the presence of toxic-metabolic encephalopathy as a cause of dementia may be questioned. This important detail in the overall EEG picture can also be observed in other pathological conditions, but its absence makes the diagnosis of toxic-metabolic encephalopathy very unlikely. Quite often, simply discontinuing the suspected drug as a possible "culprit" of intoxication ex juvantibus confirms the diagnosis, as it leads to the reverse development of confusion and dementia in the elderly.

Finally, the third group of diseases that can cause dementia are diseases that directly (primarily) affect brain tissue. They can be unifocal (e.g., a tumor or subdural hematoma) or multifocal (e.g., multiple infarctions).

Clarification of the cause of dementia within this group of nervous system diseases requires a full examination. The absence of neurological signs in some cases makes etiologic diagnosis very difficult. Lumbar puncture and CT usually help to correctly identify the nature of the pathological process, but there are exceptions. For example, some lacunar infarcts may be too small to be detected; similarly, CT manifestations of brain atrophy in many degenerative diseases may be indistinguishable from age-related changes in healthy individuals of the same age at certain stages of the disease. Neither magnetic resonance imaging, nor positron emission tomography, nor EEG mapping are often helpful in differential diagnosis in this group of patients. At the same time, the correct diagnosis of the brain disease that led to dementia is very important, since its treatment can sometimes lead to the regression of dementia (for example, evacuation of a subdural hematoma or elimination of risk factors in some forms of vascular dementia).

In "degenerative" dementias (i.e. dementias in degenerative diseases of the nervous system), there are forms where dementia may be the only manifestation of a neurological disease (Alzheimer's disease, Pick's disease). They can therefore be called "pure" dementias (exceptions to this rule are described, when the disease is combined with extrapyramidal or pyramidal signs). They are also predominantly cortical. Alzheimer's disease is associated with primary damage to mainly the posterior (parietal) brain areas. Pick's disease is a much rarer disease, affecting mainly the anterior parts of the hemispheres ("frontotemporal lobar degeneration"). But there are forms in which dementia is accompanied by motor disorders (for example, Parkinson's disease, Huntington's chorea, progressive supranuclear palsy, etc.). These are predominantly "subcortical" dementias.

Among the degenerative variants, Alzheimer's disease is the most common cause of dementia in the population of people over 65 years of age and accounts for about 50-60% of all dementias in general.

The disease begins in middle or old age, very rarely - before the age of 45. The most important symptom is a gradually progressive deterioration of memory, mainly short-term. Memory disorders are accompanied by decreased performance, a narrowing of the range of interests, and emotional lability. Gradually, along with cognitive disorders, speech disorders and disorders of visual-spatial functions develop, which significantly complicates the patient's daily activities.

Currently, the following diagnostic categories are commonly used for Alzheimer's disease: possible, probable, and definite.

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Behavioral disorders in dementia

Behavioural disorders are common in patients with dementia and may include psychotic disorders, speech or psychomotor agitation, sleep disorders, wandering, and personality changes. These manifestations cause distress to patients, create problems for their caregivers, and increase the use of health care resources. They are the main reason for seeking outpatient or emergency medical care. Behavioural disorders are very common, heterogeneous, and have a variable prognosis. Personality changes are evident early in the disease and are often described as an “exacerbation” of premorbid personality traits. They may also include irritability, apathy, detachment, and alienation from others. At a later stage of the disease, personality changes are detected in more than half of patients admitted to care facilities.

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