RU2483672C2 - Method of diagnosing functional interhemispheric asymmetry in right-handed and left-handed people - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, in particular to field of medical and psychophysiological diagnostics. Assessment of character of motor asymmetries - determination of degree of right-handedness - left-handedness by dominance of hand and leg, as well as sensor asymmetries - determination of leading eye and ear, is performed. Also calculated is coefficient of amplitude and frequency of mu-rhythm in central parts of left and right hemisphere, as ratio of difference of maximal and minimal values to their sum. Difference between maximal and minimal values is calculated within 3-second long interval. Dominating hemisphere of motor cortex by mu-rhythm is registered at the moment of alternate clenching right and left hand fist with application of sensomotor test by scheme: "Close eyes - make right fist - open eyes - undo the fist", "Close eyes - make left fist - open eyes - then undo the fist', during standard registration of electroencephalogram.

EFFECT: method extends arsenal of means for assessment of functional interhemispheric asymmetry.

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Description

The invention relates to medicine, in particular to the field of medical and psychophysiological diagnostics, and for the diagnosis of the degree of functional asymmetry in right-handed and left-handed people.

Interhemispheric asymmetry is a fundamental property of the human brain. For the first time, the modern formulation of the problem of functional interhemispheric asymmetry (FMA) in humans arose after the work of R. Vgos (1861), W. Ogle (1867), K. Wemicke (1874), H. Bastian (1882) and others, which showed lateralization of speech functions in humans.

Studies devoted to assessing the severity of sensory and motor asymmetries in left-handed and right-handed groups differ in methods for determining functional asymmetry (Annet M. The distribution of manual asymmetry // Br. J. O Psychology. 1972. V.6. P.343- 358; Fedoruk A.G., Dobrokhotova T.A. Functional asymmetries of a person in operator activity // Space Biology and Aviation Medicine. - 1980. - No. 5. - P. 39-42; Fomina E.V. Sensomotor asymmetries of athletes . - Omsk, 2003. - P.150; Bragina N.N., Dobrokhotova T.A. Functional asymmetries of a person, 2nd ed. - M .: Medicine, 1988. - P.2 03-219). The functional asymmetry of the brain, measured using various tests, speaks only about the features of specific behavioral manifestations and does not always correlate with general functional asymmetry.

The use of electroencephalography (EEG) in the analysis of interhemispheric asymmetry significantly complements the overall picture of the differences between right-handed and left-handed people. Hemispheric differences in the coherent characteristics of EEG in right-handed and left-handed people, described by various researchers, are heterogeneous and contradictory in nature, have different methodological approaches (Grindel OM, Sazonova OB, Zhirov SB. Study of the spatial structure of the alpha rhythm of a healthy person EEG mapping method. // Journal of Higher Nervous Worker - T.42. - B.2. - 1992. - P.491-499; Goldstein L. Characterization of differential hemispheric EEG activation in right- and left-handed. anthropoisometry and lateral adaptation. - Moscow - Voroshilovgrad, 19 85. - P.41; Dobrokhotova T.A., Bragina N.N. Lefthander. - M .: Medicine, 1977. - P.359; Efimova I.V., Timaeva M.A., Uvarova L.G. Interhemispheric asymmetry (MPAc) of the EEG rhythm ranges and its interindividual variability in healthy people depending on the lateralization of the leading arm // Human Physiology. - 1984. - T. 10. - No. 4. - P.515; Zhavoronkova L.A. Pravshi - left-handed people: interhemispheric asymmetry of human brain biopotentials. - Krasnodar: Ecoinvest, 2009. - P.21-64; Rusinov B.C., Grindel O.M., Boldyreva G.N., Vakar E.M. Symmetry and stability of the EEG spectra of a healthy person. // Journal. higher nerve. activist - 1976.- T.26. - Number 3. - S.576-587; Rusinov B.C., Grindel O.M., Boldyreva G.N., Vakar E.M. Biopotentials of the human brain (mathematical analysis). - M .: Medicine, 1987. - P.254; Yoshii F., Ginsberg M.D., Kelley R.E. et al. Asymmetric somatosensory activation topographic study // Brain Res. 1989. V. 48. No. 2. - P.355; Lopez da Silva F.N., Van Lierop T.N., Schrijer C.F., Storm van Leeuwen W. Organization of thalamic and cortical alpha rhythms: spectra and coherences / EEG and din. Neurophysiol. 1973. V.35. P.627; Earle J.B. Task difficulty and EEG alpha asymmetry: an amplitude and frequency analysis // Neuropsychobiology. 1988. V.20, P.96-112).

In the laboratory of clinical neurophysiology of the Institute of Neurosurgery. NN Burdenko developed a method for assessing the frequency characteristics of an EEG using the average frequency and the effective frequency band of the power spectrum. However, when analyzing biorhythms by this method, statistically significant interhemispheric differences were not found in left-handed and right-handed groups, they occur only in the alpha rhythm frequency range of right-handed people (Grindel OM, Gershman S.G., Boldyreva G.N. and other. Intercenter relations in the cerebral cortex of the human brain according to the coherence spectrum and phase spectrum of the EEG // Journal of Higher Nervous Workers - 1973. - E.23. - No. 4. - S.771-781). According to Buttler S.R. (Buttler S.R., Glass A. Asymmetries in the encephalogramm associated with cerebral dominance // EEG and din. Neurophysiol. 1978. V.45. No. 4. - P.393). Currently, there are many methods for determining interhemispheric asymmetry (patent RU No. 21155364, 07.20.1998; patent RU No. 2151548, 06.27.2000; patent RU No. 2198589, 02.20.2003). However, most of them relate to the determination of interhemispheric asymmetry using sensory and motor tests without analyzing the electrophysiological picture of the brain in the hemispheres.

There is a method for determining the degree of interhemispheric asymmetry of the brain (application RU No. 2003135904, class A61B 5/16, bull. No. 14, 2005), where the level of functional capabilities of the central nervous system (CNS of the central nervous system) is used as an indicator of the functional state of the brain. The sensorimotor test is performed unanimally with a pause of at least 7 minutes. The hemisphere asymmetry coefficient is calculated by the formula:

CAS = (UVVL-UVVp) / (UVVL + UVVp) · 100%, where UVVL is the level of the nervous system’s functionality when performing the sensorimotor test with the right hand; UVVp is the level of functionality when performing the sensorimotor test with the left hand. The disadvantage of this method is the lack of data on the reaction of biorhythms of the brain by EEG at the time of the sensorimotor test.

A known method for determining the functional state of a person with a right asymmetry profile (Zhavoronkova L.A. AS No. 1581278, 07/30/1990), which was later supplemented by the results of a detailed analysis of brain biorhythms in wakefulness and sleep in right-handed and left-handed people with the introduction of a coherent analysis program (Ka) hemisphere rhythms:

Ka = 1 / n (Cog E L1 - Cog E P1 / Cog E L1 + Cog E P1 + ... + Cog E Ln - Cog E Pn / Cog E Ln + Cog E Pn), where Cog is coherence, E is the sum, L - left, P - right (Zhavoronkova L.A. Left-handed people: interhemispheric asymmetry of human brain biopotentials. - Krasnodar: Ecoinvest, 2009. - P.21-64). However, there is no data regarding the analysis of mu rhythm (rolandic, somatosensory), which is a variant of the normal rhythm that is similar in frequency to the alpha rhythm, but differs from it in severity in various regions of the cortex (mu rhythm is recorded mainly in the central areas).

There is a method for determining the individual profile of the lateral organization (PLO) (Bragin NN, Dobrokhotova TA Functional asymmetries of a person. - M .: Medicine, - 1988. - P.203-219), adopted for the prototype, including character assessment motor asymmetries - determining the degree of right-handedness on the basis of motor dominance of the arm and leg (Fig. 1), as well as sensory asymmetries - determining the leading eye and ear. However, the technique described in the prototype for determining hemispheric asymmetry using sensory and motor tests does not reflect the full picture of functional interhemispheric asymmetry, since it does not contain an analysis of the electrophysiological picture of the brain in hemispheres.

The task of the invention is to identify reliable criteria for determining functional interhemispheric asymmetry in left-handed and right-handed people using registration of mu rhythm by EEG in various functional states of wakefulness and determining the bioelectric focus of dominance of mu rhythm in hemispheres using a sensorimotor test.

The problem is solved by introducing a method for determining the individual profile of the lateral organization using mu rhythm recorded using an electroencephalogram (EEG) in various functional states of wakefulness and with a sensorimotor test for the right and left hand.

To achieve this goal, studies were conducted in the city of Vladivostok on the basis of the NEURON Medical Center for 12 months (from 2009 to 2010). For the examination, almost healthy volunteers of both sexes were selected for 260 people aged 20-40 years. The age group was selected taking into account age-related “maturity” and EEG rhythm stability, as well as due to the absence of chronic diseases in the study group. Dynamic testing of patients was carried out at the same time of the day (from 10 to 12 hours). The determination of the individual profile of the lateral organization (PLO) (right-handed or left-handed) was carried out according to the methodology (Bragin NN, Dobrokhotova TA, 1988), volunteers with a mixed type of PLO were excluded. Then, an electroencephalogram was recorded with functional tests with an additional sensorimotor test. EEG recording was carried out in a sitting position in a darkened room according to a standard technique, including passive and active wakefulness, functional tests (opening-closing of eyes, rhythmic photostimulation of 2-30 Hz (RFU) and hyperventilation (GV) for 5 min). The electrode arrangement was used according to the International System "10-20" (Jasper, 1958) in standard leads, including the main brain areas of the right and left hemispheres: occipital (O), parietal (P), central (C), frontal (F), temporal (T). Used monopolar with a combined reference electrode and bipolar montages. Bandwidth 0.5-35 Hz, amplitude calibration 7 μV, sweep 30 mm / s. Using frequency and amplitude analysis, the dominance region was determined in the mu rhythm range by hemispheres with the construction of potential activity maps and their potential fields. All indicators were calculated separately for the right and left hemisphere.

With a detailed analysis of mu rhythm by EEG, the best visualization of mu rhythm was observed with bipolar editing in the central parietal sections, and with monopolar editing, in the central sections. Differences between left-handed and right-handed people in the localization of the dominant functional focus of mu rhythm in the hemispheres with an inverse relationship between the prevalence of mu rhythm during a sensorimotor test and the dominant hand were revealed.

Using the results obtained, a new method for diagnosing functional interhemispheric asymmetry in right-handed and left-handed people was formed, which consists in determining the individual profile of lateral organization (PL) using the EEG mu rhythm in various functional states of wakefulness (with amplitude-frequency analysis of asymmetry coefficients) and with sensorimotor breakdown according to the scheme: "Close your eyes - squeeze your right hand - open your eyes - then unclench your hand"; "Close your eyes - squeeze your left hand - open your eyes - then unclench your hand."

The method is as follows.

First, individual testing is carried out, including determining the individual profile of the lateral organization with an assessment of the nature of motor asymmetries - determining the degree of right-handedness-left-handedness by the dominance of the arm and leg, as well as sensory asymmetries - with the definition of the leading eye and ear. Then, a routine recording of EEG (in a sitting position) in a darkened room is performed according to a standard technique, including passive and active wakefulness, functional tests (opening-closing of eyes, rhythmic photostimulation of 2-3 0 Hz (RFU) and hyperventilation (GV) for 5 min.) . The arrangement of electrodes according to the International System "10-20" (Jasper, 1958) in standard leads with the inclusion of the main brain zones of the right and left hemispheres is used. Monopolar with integrated reference electrode and bipolar mountings are used. Bandwidth 0.5-35 Hz, amplitude calibration 7 μV, sweep 30 mm / s. The analysis is performed on artifact-free EEG segments with a fixed period of 3 seconds of sections with better visualization of mu rhythm in the central (C) and central-parietal leads (CP). All indicators are calculated separately for the right and left hemisphere. Then determine the bioelectric functional focus of the dominance of mu rhythm in the hemispheres during a sensorimotor test carried out according to the scheme: "Close your eyes - squeeze your right hand - open your eyes - then unclench your hand"; "Close your eyes - squeeze your left hand - open your eyes - then unclench your hand."

For the analysis of mu rhythm, amplitude-frequency asymmetry coefficients are developed.

The amplitude asymmetry coefficient is calculated by the formula:

KAA = (R (Nmax-Nmin) l-R (Nmax-Nmin) p) / (R (Nmax-Nmin) l + R (Nmax-Nmin) p) × 100%,

where KAA is the coefficient of amplitude asymmetry, R = Nmax-Nmin is the difference between the maximum (Nmax) and minimum (Nmin) points within the interval in the central leads in 3 seconds; l - left, n - right hemisphere.

The frequency asymmetry coefficient is calculated by the formula:

CFA = (R (Nmax-Nmin) l-R (Nmax-Nmin) p) / (R (Nmax-Nmin) l + R (Nmax-Nmin) p) × 100%;

where CFA is the coefficient of frequency asymmetry, R = Nmax-Nmin is the difference between the maximum (Nmax) and minimum (Nmin) points within the interval in the central leads in 3 seconds; l - left, n - right hemisphere.

The method is illustrated by illustrative material, where

figure 1 shows a projection diagram of the sensorimotor region of the right and left hands;

figure 2 and 3 shows a fragment of the electroencephalogram S., 30 years old (right-handed) (bipolar installation), with the analysis of the difference in the spectrogram between mu rhythm and alpha rhythm (μV);

Figures 4 and 5 show a fragment of an electroencephalogram S., 30 years old (right-handed) (monopolar editing), with determination of the focus of mu rhythm dominance from the cartogram during the sensorimotor test (μV);

6 and 7 show a fragment of the electroencephalogram K., 30 years old (left-handed) (bipolar editing), with the analysis of the difference in the spectrogram between mu rhythm and alpha rhythm (μV);

Figures 8 and 9 show a fragment of the electroencephalogram K., 30 years old (left-handed) (monopolar editing), with the focus being determined by the mu rhythm from the cartogram during the sensorimotor test (μV).

The method is illustrated by the following examples.

As an example, we took two volunteers (without organic brain diseases) a right-handed person and a left-handed person of the same male age. An individual profile of the lateral organization is determined with conducting an electroencephalogram in various functional states of wakefulness and with a sensorimotor test, an amplitude-frequency analysis of the mu rhythm is carried out in comparison with the cortical rhythm (alpha rhythm) in various areas of the brain.

Example 1: S., 30 years old (right-hander).

Volunteer S. (male 30 years old), for testing PLO - right-handed (lead eye - right, lead ear - right, lead hand - right, lead leg - right).

Tables 1 and 2 present a comparative analysis of the average values for the amplitudes and frequency of mu and alpha rhythms in different areas of the brain, indicating the presence of patterns in the interhemispheric distribution of mu and alpha rhythms depending on the dominant hemisphere.

Table 1 Comparative analysis of average values for the amplitudes and frequency of mu and alpha rhythms in different areas of the brain in the right-hander (S. 30 years) (μV) Brain projection areas Mu rhythm Alpha rhythm Left (1) Right (2) Left (1) Right (2) Central and parietal-central leads (C, C-P) (μV) fifty 42.3 - - Occipital and parieto-occipital leads (O, P-O) (μV) 23.3 eighteen

table 2 Comparative analysis of average values for the amplitudes and frequency of mu and alpha rhythms in different areas of the brain in the right-hander (S. 30 years) (μV) Brain projection areas Mu rhythm Alpha rhythm Left (1) Right (2) Left (1) Right (2) Central and parietal-central leads (C, C-P) (Hz) 11.1 10 - - Occipital and parieto-occipital leads (O, P-O) (Hz) - - 9.8 8.5

A spectral analysis of mu rhythm was carried out in comparison with alpha rhythm in the projection areas of dominance in the hemispheres (Tables 1, 2 and 2, 3). According to the EEG data, a difference was found in the amplitude-frequency dominance of the mu rhythm in the hemispheres. A similarity was found in the frequency-amplitude dominance of mu rhythm and alpha rhythm in the left hemisphere. However, there are differences in mu rhythm and alpha rhythm: mu rhythm is better visualized with bipolar editing, and alpha rhythm is better visualized with monopolar editing; mu rhythm is recorded by monopolar editing in the central parts of the left hemisphere, with bipolar editing - in the central parietal parts of the left hemisphere, and the alpha rhythm - in the occipital region of the left hemisphere. Using KAA and KChA revealed the difference in the amplitude and frequency of mu rhythm in the Central departments (C) of the right-hander:

1) the amplitude of R on the left is 50 μV, R on the right is 42.3 μV

KAA = 7.7 / 92.3 × 100% = 8.3%;

2) the frequency R on the left is 11.1 Hz, R on the right is 10 Hz

CNA = 1.1 / 21.1 × 100% = 5.2%.

According to the sensorimotor test - at the time of squeezing of the right hand, the mu rhythm was not completely suppressed, followed by the predominance of mu rhythm in the sensorimotor region of the left hemisphere, which is a reflection of the cortical representation of the function of the right hand.

Example 2: K. 30 years (left-handed).

Volunteer K. (male 30 years old), according to PLO - left-handed (lead eye - left, lead ear - left, lead hand - left, lead leg - left).

Tables 3-4 provide a comparative analysis of the average values for the amplitude and frequency of mu rhythm and alpha rhythm in different areas of the brain.

Table 3 Comparative analysis of the average values of the amplitudes of mu and alpha rhythms in different areas of the brain in left-handed people (K. 30 years) (μV) Brain projection areas Mu rhythm Alpha rhythm Left (1) Right (2) Left (1) Right (2) Central and parietal-central leads (C, C-P) (μV) 53.9 65.3 - - Occipital and parieto-occipital leads (O,
PO) (μV) - 28 32

Table 4. Comparative analysis of average values for the frequency of mu and alpha rhythms in different areas of the brain in left-handed people (K. 30 years) (Hz) Brain projection areas Mu rhythm Alpha rhythm Left (1) Right (2) Left (1) Right (2) Central and parietal-central leads (C, C-P) (Hz) 10.8 11,4 - - Occipital and parieto-occipital leads (O, P-O) (Hz) - - 9.3 10

The spectral analysis of mu rhythm was carried out in comparison with the alpha rhythm in the projection areas of dominance in the hemispheres (Tables 3, 4 and Figs. 4, 5). According to the EEG data, a difference was found in the amplitude-frequency dominance of the mu rhythm in the hemispheres. The similarity in the frequency-amplitude dominance of mu rhythm and alpha rhythm in the right hemisphere was determined. However, differences in mu rhythm and alpha rhythm were revealed: mu rhythm is better visualized with bipolar editing, and alpha rhythm is better visualized with monopolar editing; mu-rhythm is recorded by monopolar editing in the central departments of the right hemisphere, with bipolar editing - in the central parietal parts of the right hemisphere, and the alpha rhythm - in the occipital region of the right hemisphere. Using KAA and CFA, the difference in the amplitude and frequency of the mu rhythm in the central sections (C) of the left-handed person was revealed:

1) the amplitude of R on the left is 53.9 μV, R on the right is 65.3 μV,

KAA = -11.4 / 119.2 × 100% = - 9.5%;

2) the frequency R on the left is 10.8 Hz, R on the right is 11.4 Hz,

CFA = -0.6 / 22, 2 × 100% = - 2.7%.

According to the sensorimotor test, at the moment of compression of the left hand, the mu rhythm was not completely suppressed, followed by the predominance of the mu rhythm in the sensorimotor region of the right hemisphere, which is a reflection of the cortical representation of the left hand function.

According to the results of the survey (examples 1 and 2), the dominance of mu rhythm in amplitude and frequency, as well as resistance to samples, is observed on the contralateral side with respect to the dominant hemisphere. For the right-handed person, the difference between the maximum and minimum values of mu rhythm is greater in the central parts of the contralateral hemisphere on the left, and for the left-handed person - on the right. The asymmetry coefficients in amplitude and frequency are positive in the right-handed person and negative in the left-handed person. When a sensorimotor test (clenching the hand into a fist) does not completely suppress the EEG mu rhythm in the central parts of the contralateral side of the hemisphere with respect to the dominant arm.

Comparative analysis with the prototype shows that in order to determine the functional interhemispheric asymmetry, in addition to determining the individual profile of the lateral organization (right-handed and left-handed), the amplitude-frequency analysis of mu-rhythm is used for the first time with the calculation of the amplitude and frequency asymmetry coefficients during recording of the electroencephalogram in various waking functional states (passive-active wakefulness, photostimulation, hyperventilation), and to determine the bioelectric focus of the dominance of mu- a hemorrhage rhythm is performed by a sensorimotor test according to the scheme: "Close your eyes - squeeze your right hand - open your eyes - then unclench your hand", "Close your eyes - squeeze your left hand - open your eyes - then unclench your hand."

The practical significance of the search for exact criteria for functional interhemispheric asymmetry is that on this basis an earlier diagnosis of incomplete adaptation of the organism is possible, a sign of which is the inversion of hemispheric dominance, which may underlie psychosomatic, neurotic diseases and addictive behavior. There is evidence of different adaptation strategies for people with unequal profiles of functional interhemispheric asymmetry: social stressors better tolerate individuals with right and natural ones with left profiles; in comfortable climatic and geographical conditions of a stereotypical environment, right-hemispheric individuals get an advantage, and in extreme constantly changing environmental conditions people with left and symmetrical profiles are more effective (Leutin V.P., Nikolaeva E.I. Psychophysiological adaptation mechanisms and functional asymmetry. - Novosibirsk. - Science, 1988 .-- P.193).

Accurate diagnostics of functional interhemispheric asymmetry makes it possible to increase the efficiency of professional selection of people for various types of labor and sports activities, as well as to develop optimal methods for teaching and training subjects of the educational space, implementing an individual approach to a specific person.

A method for diagnosing functional interhemispheric asymmetry in right-handed and left-handed people is necessary to study the biological foundations of individual differences between right-handed and left-handed people, to identify the role of individual typological properties in labor, educational, and sports activities and to assess the prognosis for diseases of the nervous system depending on the dominant hemisphere of the brain.

Claims (1)

A method for evaluating functional interhemispheric asymmetry in right-handed and left-handed people, including determining the individual profile of the lateral organization: including assessing the nature of motor asymmetries - determining the degree of left-handedness by the dominance of the arm and leg, as well as sensory asymmetries - determining the leading eye and ear, characterized in that the coefficient of asymmetry of the amplitude and frequency of mu rhythm in the central parts of the left and right hemisphere is calculated by the formula: KA = R (Nmax-Nmin) l-R (Nmax-Nmin) n) / (R (Nmax-Nmin) l + R ( Nmax-Nmin) p) · 100%, where KA is the coefficient asymmetries, l is the left hemisphere, n is the right hemisphere, R (Nmax-Nmin) is the difference between the maximum and minimum values within an interval of 3 s; the dominant hemisphere of the motor cortex according to mu rhythm is recorded at the moment of alternating compression of the right and left hands into a fist using a sensorimotor test according to the scheme: “Close your eyes - squeeze your right hand - open your eyes - then unclench your hand”, “Close your eyes - squeeze your left hand - open your eyes - then unclench your hand ”, during standard recording of the electroencephalogram.

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