RU2515398C1 - Differential diagnostic technique for cognitive disorders accompanying toxic encephalopathy caused by effect of mercury and alcohol - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: neuropsychological testing aims at determining an analytic-synthetic thinking index; a depression index; a trait anxiety index; a state anxiety index; a mental alertness index; a psychomotor activity rate, and recording an electroencephalography to measure β1-rhythm and β2-rhythm. A diagnostic function F is calculated; the derived value is compared to a constant, and if F is more than the constant, the cognitive disorders accompanying encephalopathy caused by an effect of alcohol are diagnosed; if F is equal to or less than the constant, the cognitive disorders accompanying chronic mercury intoxication are diagnosed.

EFFECT: technique enables providing more accurate differentiation of the cognitive disorders accompanying toxic encephalopathy caused by the effect of mercury, and alcoholic encephalopathy.

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Description

The invention relates to medicine, namely to neurology, occupational pathology and neuropsychology.

When diagnosing mercury intoxication, doctors often have to resort to differential diagnosis of toxic encephalopathy of mercury origin from encephalopathy of another etiology. Most often, a differential diagnosis is made with encephalopathy of vascular origin, but in some cases it is necessary to distinguish the signs of mercury encephalopathy from brain damage of alcoholic origin.

Establishing the genesis of cognitive impairment is important when conducting an examination of the connection between a disease and a profession and determining the percentage of disability: in the case of a combined lesion, the percentage of disability decreases.

However, unified approaches to the differential diagnosis of brain damage in toxic (mercury) encephalopathy and alcoholic encephalopathy accompanied by impaired cognitive functions have not yet been developed. The need to develop adequate methods of differential diagnosis is justified by the fact that cognitive changes make a significant contribution to the clinical picture of toxic encephalopathy. These symptoms can reduce the quality of life of patients, make it difficult to adapt to a chronic disease, the rehabilitation process. Meanwhile, the presence of brain dysfunction, even in minimal volumes, is a risk factor for the development of more pronounced disorders of higher mental functions, which aggravates the prognosis of the disease.

Known methods for the diagnosis of cognitive impairment, including clinical neurological examination, electroencephalography (EEG), a psychological study of the emotional-volitional and mnestic-intellectual spheres, neuroimaging methods [1-8]. However, these methods do not allow differentiating the signs of cognitive deficit in toxic encephalopathy of various origins.

The closest is a method for detecting disorders of higher mental functions in encephalopathy of various origins, including, in addition to comparing the clinical picture of the disease, the use of neuropsychological research methods according to A.R. Luria [10] with an assessment of the state of intelligence, memory: tests “4th extra”, “broken window”, “triple counting”, “performing simple counting operations”, “selection of opposites”, “10 words”, “memorizing groups images during three reproduction ”, praxis:“ fist-rib-palm ”tests, Head, Ozeretsky, gnosis: recognition of crossed out, superimposed images, recognition of non-speech noises and familiar melodies, showing a given finger by sample and by name and speech: tests for understanding logical-grammatical constructions, "ordinal count from 1 to 10, listing the days of the week, months, the completion of well-known proverbs ”, to repeat sounds, a series of sounds, words and phrases [4]. However, the differentiation of disorders, the determination of the genesis of cognitive impairment in toxic encephalopathy from exposure to mercury and concomitant alcoholic brain damage is difficult due to the lack of clear differences.

The objective of the invention is to improve the accuracy of differential diagnosis of cognitive impairment in toxic encephalopathy from exposure to mercury and alcohol.

The problem is solved by identifying violations in the cognitive sphere using a neurophysiological examination, including electroencephalography (EEG) with the determination of β-rhythm by EEG; β2 rhythm by EEG; neuropsychological testing with the determination of indicators of analytical and synthetic thinking; level of depression, level of personal anxiety; level of reactive anxiety; concentration of attention; the pace of psychomotor activity; calculation of discriminant function using the obtained indicators, followed by assigning the patient to a group with cognitive impairment in toxic encephalopathy due to mercury exposure or to a group with cognitive impairment in alcohol encephalopathy.

A comparative analysis of the proposed solution with the prototype [4] shows that a common feature is the conduct of neuropsychological tests. The proposed method is characterized in that electroencephalography is additionally performed and β1-rhythm and β2-rhythm indicators are determined, after which the discriminant function F is calculated, and when F has more than a constant, patients are diagnosed with cognitive impairment from encephalopathy due to alcohol, if F is less than or equal to a constant, they are diagnosed cognitive impairment in chronic mercury intoxication.

Thus, the proposed technical solution meets the criteria of the invention of "novelty."

At present, the capabilities of the neuropsychological method for studying the effects of organic brain damage and many other diseases, including neuroses and psychoses, are known [1, 2, 6-12].

The use of the proposed complex of indicators obtained using these tests for mathematical calculation in order to identify differential diagnostic criteria for cognitive impairment in toxic encephalopathy from exposure to mercury and alcohol has not been identified in the literature available to us.

The use of EEG in the diagnosis of toxic mercury encephalopathy is known. The authors did not find descriptions of how to use EEG indicators to differentiate cognitive impairment in toxic encephalopathy from mercury exposure with concomitant alcoholic brain damage.

Thus, the proposed method meets the criterion of "inventive step".

The developed method can be used by neurologists, psychiatrists, occupational pathologists, therapists, neuropsychologists, physiologists for the differentiated diagnosis of cognitive impairment in toxic encephalopathy from exposure to mercury and alcohol during medical and social examination. Thus, the method meets the criterion of "industrial applicability".

The method is as follows.

The patient undergoes a neurophysiological examination, including electroencephalography with the determination of β1 rhythm by EEG (a ₁ ) in%; β2 rhythm by EEG (a2) in%; neuropsychological testing with the determination of indicators of analytical-synthetic thinking (a ₃ ) in points; the level of depression (a ₄ ) in points, the level of personal anxiety (a ₅ ) in points; level of reactive anxiety (a ₆ ) in points; concentration of attention (a ₇ ) in points; the rate of psychomotor activity (a ₈ ) in points. Calculate the diagnostic function according to the formula:

F = 830.4-0.53 × a ₁ + 1.35 × a ₂ + 11.65 × a ₃ -1.14 × a ₄ -0.72 × a ₅ -0.68 × a ₆ +0, 72 × a ₇ -12.35 × a ₈ ,

where F is a diagnostic function;

830.4 is a constant;

0.53; 1.35; 11.65; 1.14; 0.72; 0.68; 0.72; 12.35 - discrimination factors;

a _{1, 2 ... 8} - numerical values of the indicators of the survey;

a ₁ - indicator of the β1 rhythm by EEG in%; and ₂ is an indicator of the β2 rhythm by EEG in%; and _{3 -} indicator of analytical and synthetic thinking in points; and ₄ is an indicator of the level of depression in points; and ₅ is an indicator of the level of personal anxiety in points; and ₆ is an indicator of the level of reactive anxiety in points; and ₇ is an indicator of concentration in points; and ₈ is an indicator of the pace of psychomotor activity in points. The result is compared with a constant: when F is more than a constant, cognitive impairment is diagnosed with encephalopathy from exposure to alcohol, if F is less than or equal to a constant, cognitive impairment is diagnosed in chronic mercury intoxication.

As a result of the discriminant analysis, to determine the differential diagnostic criteria for encephalopathy of toxic genesis from exposure to mercury and alcohol according to neurophysiological and neuropsychological indicators, an optimal combination of 8 signs was obtained, at which the diagnostic accuracy was maximum.

The discriminant analysis was performed in a group of patients with chronic mercury intoxication in the long-term period, patients with alcohol encephalopathy, and in conditionally healthy patients who did not have intoxication in the professional route of contact with harmful substances.

The reliability and contribution of the obtained informative indicators to the equation of canonical value are presented in tables 1, 2.

Table 1 Informative indicators of discriminant analysis No. Indicators (points) F inclusion R a ₁ EEG β2-rhythm,% 31.3 0.000004 a ₂ Depression Level, (points) 21.5 0.00006 a ₃ β1-rhythm by EEG,% 10.9 0.002 a ₄ The pace of psychomotor activity, (points) 9.0 0.005 a ₅ The level of personal anxiety, (points) 4.8 0,03 a ₆ The level of reactive anxiety, (points) 4.4 0.04 a ₇ Concentration of attention, (points) 4.2 0.04 a ₈ Synthetic-analytical thinking, (points) 4.0 0.05

table 2 Contribution of indicators to the equation of canonical quantity EEG β2-rhythm,% 24.7% Depression Level, (points) 15.5% β1-rhythm by EEG,% 12.2% The pace of psychomotor activity, (points) 10.7% The level of personal anxiety, (points) 9.5% The level of reactive anxiety, (points) 8.7%

Concentration of attention, (points) 8.5% Synthetic-analytical thinking, (points) 8.2%

The calculation of the diagnostic functions F ₁ and F _{2 is} performed according to the formulas:

F ₁ = -476.7 + 0.62 × a ₁ -0.22- × a ₂ -6.9 × a ₃ + 2.26 × a ₄ + 0.98 × a ₅ + 0.62 × a ₆ -0.07 × a ₇ + 34.0 × a ₈ ;

F ₂ = -353.7 + 1.15 × a ₁ -2.1 × a ₂ -17.2 × a ₃ + 3.4 × a ₄ + 1.7 × a ₅ -0.06 × a ₆ - 0.11 × a ₇ + 46.35 × a ₈ ;

where F _{1 is a} diagnostic function for encephalopathy from exposure to mercury;

F ₂ - diagnostic function for encephalopathy from exposure to alcohol;

-476.692 and -353.749 are constants;

0.62; - 0.22; - 6.9; 2.26; 0.98; 0.62; - 0.07; 34.0; 1.15; -2.1; -17.2; 3.4; 1.7; -0.06; - 0.11; 46.35 - discrimination factors;

a _{1, 2 ... 8} - numerical values of the indicators of the survey: a ₁ - indicator of the β1 rhythm by EEG in%; and ₂ is an indicator of the β2 rhythm by EEG in%; and ₃ is an indicator of analytical-synthetic thinking according to the results of a neuropsychological examination in points; and ₄ - the level of depression in points; and ₅ - the level of personal anxiety in points; and ₆ - level of reactive anxiety in points; a ₇ - an indicator of concentration in points; a ₈ is an indicator of the pace of psychomotor activity in points.

Diagnostic function F is obtained by subtracting discriminant functions for toxic encephalopathy from exposure to mercury and for encephalopathy from exposure to alcohol.

F = 830.4-0.53 × a ₁ + 1.35 × a ₂ + 11.65 × a ₃ -1.14 × a ₄ -0.72 × a ₅ -0.68 × a ₆ +0, 72 × a ₇ -12.35 × a ₈

Example 1

Patient D. (age 47 years, work experience in the mercury electrolysis workshop at a chemical plant for 9 years, was observed by a narcologist with a diagnosis of alcoholism for some time), with complaints of persistent headaches, dizziness of a non-systemic nature, memory loss for current events, electroencephalography, neuropsychological testing with the definition of indicators of analytical and synthetic thinking, the level of depression, levels of personal and reactive anxiety, the indicator of concentration, the rate of psychomotor d activities and their numerical values are defined:

a ₁ - index β1 by EEG - 8%,

and ₂ - β2 index by EEG - 10%,

and ₃ - an indicator of analytical-synthetic thinking - 0.6 points,

and ₄ - an indicator of the level of depression according to V. Zung - 48 points,

a ₅ - indicator of the level of personal anxiety - 49 points,

and ₆ - an indicator of the level of reactive anxiety - 49 points,

and ₇ - an indicator of concentration of attention - 240 points,

a ₈ is an indicator of the pace of psychomotor activity - 1.8 points.

F = 830.4-0.53 × 8 + 1.35 × 10 + 11.65 × 0.6-1.14 × 48-0.72 × 49-0.68 × 49 + 0.72 × 240- 12.35 × 1.8-873.9,

F> constants.

Conclusion: Patient D. has cognitive impairment in toxic encephalopathy of alcoholic origin.

Example 2

Patient Z. (51 years old, work experience in the mercury electrolysis workshop at a chemical plant for 14 years, according to alcohol he uses no more than 1 time per week, no more than 100 g) with complaints of irritability, general weakness, headaches, sleep disturbance, memory loss, conducted electroencephalography, neuropsychological testing with the definition of indicators of analytical and synthetic thinking, the level of depression, levels of personal and reactive anxiety, an indicator of concentration, an indicator of the rate of psychomotor activity and Delena their numerical values:

a ₁ - index β1 by EEG - 25%,

and ₂ - β2 index by EEG - 2.2%,

and ₃ - an indicator of analytical-synthetic thinking - 0.7 points,

and ₄ - an indicator of the level of depression according to V. Zung - 69 points,

and ₅ - an indicator of the level of personal anxiety - 60 points,

and ₆ - an indicator of the level of reactive anxiety - 57 points,

and ₇ - an indicator of concentration of attention - 173 points,

a ₈ is an indicator of the pace of psychomotor activity - 1.3 points.

F = 830.4-0.53 × 25 + 1.35 × 102.2 + 11.65 × 0.7-1.14 × 69-0.72 × 60-0.68 × 57 + 0.72 × 173-12.35 × 1.3 = 776.1,

F <constants.

Conclusion: Patient Z. has cognitive impairment in chronic mercury intoxication.

Example 3

Patient B., age 49 years (work experience in the mercury electrolysis workshop at a chemical plant is 11 years, according to the words - he drinks alcohol 1-2 times a week from 100 to 200 g), with complaints of general weakness, decreased mood, frequent headaches, memory loss, dizziness of a non-systemic nature conducted electroencephalography, neuropsychological testing with the definition of indicators of analytical and synthetic thinking, the level of depression, levels of personal and reactive anxiety, concentration indicator, rate of psychic motor activity and determine their numerical values:

a ₁ - index β1 by EEG - 21%,

and ₂ - β2 index by EEG - 7%,

and ₃ - an indicator of analytical-synthetic thinking - 0.7 points,

and ₄ - an indicator of the level of depression according to V. Zung - 56 points,

a ₅ - indicator of the level of personal anxiety - 51 points,

and ₆ - an indicator of the level of reactive anxiety - 52 points,

and ₇ - an indicator of concentration of attention - 208 points,

a ₈ is an indicator of the pace of psychomotor activity - 1.64 points.

F = 830.4-0.53 × 21 + 1.35 × 7 + 11.65 × 0.7-1.14 × 56-0.72 × 51-0.68 × 52 + 0.72 × 208- 12.35 × 1.64 = 830.4, F = constant.

Conclusion: Patient B. has cognitive impairment in chronic mercury intoxication.

Evaluation of the effectiveness of the proposed diagnostic method was carried out in training and control samples. In the training samples (36 and 30 people), the correct recognition was 90% for patients with toxic encephalopathy, 100% for patients with alcoholic encephalopathy, and 100% for conditionally healthy patients who did not have intoxication in the professional route of exposure to harmful substances (30 person).

The proposed method improves the accuracy of differential diagnosis of cognitive impairment in toxic encephalopathy from exposure to mercury and alcohol and helps to reduce the volume of paraclinical studies.

Literature:

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Claims (1)

A method for differential diagnosis of cognitive impairment in toxic encephalopathy from exposure to mercury and alcohol, including neuropsychological testing, characterized in that electroencephalography is performed with determination of β1-rhythm and β2-rhythm, neuropsychological testing with determination of indicators of analytical and synthetic thinking; level of depression; level of personal anxiety; level of reactive anxiety; concentration of attention; the pace of psychomotor activity; calculate the discriminant function F by the formula:
F = 830.4-0.53 × a ₁ + 1.35 × a ₂ + 11.65 × a ₃ -1.14 × a ₄ -0.72 × a ₅ -0.68 × a ₆ +0, 72 × a ₇ -12.35 × a ₈ ,
where F is a diagnostic function;
830.4 is a constant;
0.53; 1.35; 11.65; 1.14; 0.72; 0.68; 0.72; 12.35 - discrimination factors;
a _{1, 2 ... 8} - numerical values of the indicators of the survey;
a ₁ - indicator of the β1 rhythm by EEG in%; a ₂ - indicator of the β2 rhythm by EEG in%; and ₃ is an indicator of analytical-synthetic thinking in points; and ₄ is an indicator of the level of depression in points; a ₅ is an indicator of the level of personal anxiety in points; and ₆ is an indicator of the level of reactive anxiety in points; a ₇ - an indicator of concentration in points; a ₈ is the indicator of the rate of psychomotor activity in points, and the result is compared with a constant: with F, the constants are diagnosed with cognitive impairment due to alcohol exposure, and with F, the cognitive impairment with chronic mercury intoxication is diagnosed with less than or equal to a constant.