Changes In Bioelectrical Activity Research Articles

Effect of sleep-disordered breathing on stable electroencephalographic characteristics during night sleep in patients with arterial hypertension

Introduction. Obstructive sleep apnea (OSA) is the most common sleep-disordered breathing condition. A significant number of OSA patients often present with cardiovascular comorbidities, particularly arterial hypertension. OSA is associated with changes in bioelectrical activity of the brain, such as slowing of electroencephalographic activity in the cortex and reduced interhemispheric synchronization. These changes can become pathophysiological markers of sleep-disordered breathing.Aim. To investigate the effect of sleep-disordered breathing on a range of quantitative electroencephalogram (EEG) characteristics during nighttime sleep in patients with arterial hypertension and clinically significant OSA.Materials and methods. The material for this retrospective study consisted of 84 polysomnographic records of patients predominantly diagnosed with arterial hypertension. Patients were divided into three groups based on the apneahypopnea index (AHI). Polysomnographic records were used to assess the synchronization measure of brain electrical activity between occipital EEG leads. The synchronization measure was evaluated using a method based on wavelet bicoherence calculation.Results. Statistically significant differences were observed in the low-frequency ranges Δf1-Δf4: 0.2-1.0 Hz, 0.8-1.6 Hz, 1.0-2.0 Hz, 1.0-4.0 Hz. In these frequencies, the interhemispheric synchronization measure significantly decreased with increasing severity of apnea.Conclusion. To determine the severity of obstructive sleep apnea, a parameter based on the synchronization measure evaluated from symmetrical occipital EEG signals in the frequency ranges 0.2-1.0 Hz, 0.8-1.6 Hz, 1.0-2.0 Hz, and 1.0-4.0 Hz can be considered. This may serve as the basis for developing and implementing new diagnostic tools for assessing the severity of sleep-disordered breathing in practice.

Trends in Amplitude-Integrated Electroencephalography in the Smallest Preterm Neonates.

Amplitude-integrated electroencephalography is increasingly used for the neuromonitoring of premature infants. However, it is still not clear how bioelectrical activity changes in the smallest gestational age newborns. The aim of our study was to evaluate the bioelectrical activity of amplitude-integrated electroencephalograms in premature newborns of different gestational age to assess how gestational age and postnatal age influence patterns of amplitude-integrated electroencephalograms and to test the hypothesis of whether the bioelectrical activity of the brain matures faster after the birth of premature newborns than in utero. We prospectively included infants born before 32 weeks of gestational age between June 2020 and July 2022. Serial recordings of amplitude-integrated electroencephalograms were performed at three time points of age (days 1-3, 13-15, and 27-29). Recordings were analyzed for background patterns, the onset and appearance of cyclicity, and lower amplitude border and bandwidth, which were used to derive a composite Burdjalov score. In total, 140 premature neonates were included in the study, and 112 of them completed the study. The median gestational age of the newborns enrolled in the study was 29 (27-30) weeks, and the mean weight was 1206 (350) g. Burdjalov scores increased with increasing gestational age. Higher scores were observed in every dimension of the amplitude-integrated electroencephalograms for newborns of lower gestational age when compared to newborns of higher gestational age of the same postmenstrual age. There was a significant correlation between gestational age and parameters of amplitude-integrated electroencephalograms at all time points. A higher gestational age has a positive effect on the bioelectrical activity of amplitude-integrated electroencephalograms. Increasing postnatal age affected amplitude-integrated electroencephalograms more than gestational age. Our hypothesis that the bioelectrical activity of the brain matures faster for premature newborns after birth than in the womb was confirmed.

COGNITIVE IMPAIRMENT AND THE IMPACT OF INTERHEMISPHERIC ASYMMETRY ON THE COURSE OF STRUCTURAL EPILEPSY

A study of patients suffering from structural epilepsy was carried out taking into account the state of the cognitive sphere and lateralization of the epileptogenic focus. It was found that the development of cognitive dysfunction was related to a number of factors. The neurophysiological researches have shown causality of cognitive disorders with functional changes of bioelectrical activity in certain parts of the brain.

Neurophysiological isolation of individual rhythmic brain activity arising from auditory-speech load

Knowledge about the rhythmic activity of neural networks associated with the implementation of a particular brain function can be used to construct diagnostic systems for objective analyses of cognitive dysfunctions. The aim of this study was to identify specific frequency-based electroencephalogram phenomena associated with speech processing. The study included data from 40 clinically healthy volunteers aged 30 to 50 years (median 32.5 years), including 23 men and 17 women. While listening to a speech stimulus, changes in bioelectrical activity over the speech centers were recorded in 23 subjects (58%). During active speech production, similar changes were recorded in 12 subjects (30%). A pairwise comparison of electroencephalogram frequencies recorded during background recording and listening to the stimuli revealed statistically significant differences in changes in rhythmic activity over Broca’s area during listening and over Wernicke's area during active speech production, while changes in rhythmic activity over Broca’s area during active speech production and over Wernicke's area during listening were less significant. The most characteristic changes in the bioelectrical activity over the speech centers during listening and speaking were fluctuations with a frequency (on average) of 17.5–17.7 Hz. This may reflect a specific electroencephalogram rhythm associated with activity in the speech areas of the brain, which could allow these regions to be more accurately identified during auditory-verbal processing.

Bioelectric activity of a brain and cerebral hemodynamics in skiers of military age over seasons of the year

INTRODUCTION: The heavy training load in extreme climatic conditions of the European North inevitably requires adaptive reactions from the athlete’s body, consequently, influencing on functional performance of the central nervous system.OBJECTIVE: To identify the patterns of seasonal changes of bioelectric activity and cerebral hemodynamics in skiers of military age.MATERIALS AND METHODS: The study involved 20 skiers of military age. The study was conducted over a year and included 4 stages, relevant to athletes’ preparation stages. In the course of work the indicators of bioelectric activity and brain cerebral hemodynamics were registration, using electroencephalograph NMG «Neurocartograph-8» and reograph «Diamant-R». Psychological status assessment was conducted using the anxiety and depression test, according to the method of A. A. Karelin.RESULTS: As a result of the study, it was found that skiers of military age experience deterioration in cerebral hemodynamics and brain bioelectric activity with the increase in training and negative factors of the North.CONCLUSION: Functioning of the athlete’s body in the European North results in deterioration of cerebral hemodynamics and brain bioelectric activity and increase of anxiety-depressive conditions in the winter preparation stage.

CHANGES IN THE BIOELECTRIC ACTIVITY OF MUSCULUS MASSETER IN CASE OF MANDIBLE EDENTULOUSNESS TREATMENT

The objective of the research: to define the dynamics of changes in bioelectric activity of mm. masseter dexter et sinister in patients with mandible edentulousness treated by means of four implant-supported dental prostheses of various types.
 105 patients were examined at the premises of the Center of Dentistry of the University Clinic of Ivano-Frankivsk National Medical University. 30 individuals out of 105 at the age of 23-28 with intact dentition, without somatic pathology were included in the control group.
 75 patients with mandible edentulousness underwent clinical examination, prosthodontic treatment, and follow-up. 3 clinical groups (Group I; II; III) were formed from this cohort of patients depending on the structural features of the manufactured dental prostheses.
 We conducted electromyography of mm. masseter dexter et sinister to the patients of the examination groups (n = 75) and the control group (n = 30) in order to achieve the objective of the research. The examination was performed by means of two-channel electroneuromyographic complex “Neuro-EMG-Micro” (“Neurosoft”) in the functional diagnostics office at the premises of the Department of Dentistry of Postgraduate Study Faculty at IFNMU.
 Quantitative indicators of bioelectrical activity of the right and left masticatory muscles were analyzed. Namely, the average values of the maximum amplitudes (μV) when performing the test of maximum bite force were analyzed. Recording of electromyographic indicators was performed before the prosthodontic treatment, 14 days after the fixation of the dental prosthesis, in 6 months and 12 months after the dental prosthesis functioning in order to study the dynamics of changes in the indicators of the examination groups.
 Electromyography recording and analysis of the findings in the individuals of the control group was performed once.
 Analyzing quantitative indicators of electromyographic examination significant differences in the dynamics of an increase in the indicators in 12 months compared to the initial indicators depending on the type of fixed dental prosthesis (subgroup A рІ-ІІІ<0.001; subgroup B рІ-ІІІ<0.001) and the order of prosthodontic treatment (рА-Б <0.001 for all groups of patients) were observed.
 
 Despite the fact that bioelectric indicators of mm. masseter dexter et sinister activity in the patients of the examination groups approximated to the indices of the control group, the dynamics of change was not equivalent and depended on the type of the dental prosthesis.
 The dynamics of an increase in the indicators of the patients in the examination groups differed by growth, however, the greatest increase was recorded in the period of “14 days” – “6 months” after the fixation of the dental prosthesis.
 On performing the test of maximum bite, the indicators of the masticatory muscles bioelectrical activity increased during the period named “before the treatment” – “12 months of functioning” most of all in IIIA examination group – by 66.52% (рd<0.001) on the right and by 76.37% (рd<0.001) on the left; and IIIB examination group – by 61.63% (рd<0.001) on the right and 67.20% (рd<0.001) on the left. The lowest indicators have increased in patients of IA examination group – 39.98% (рd<0.001) on the right and 39.95% (рd<0.001) on the left and IB examination group – by 32.48% (рd<0.001) on the right and by 34.75% (рd<0.001) on the left.

NEUROPROTECTIVE ACTION OF BUTORPHANOL AND RU-1205 WITH EVALUATION OF THEIR EFFECT O N THE BIOELECTRICAL ACTIVITY OF THE BRAIN IN THE GLOBAL ISCHEMIA MODEL

Since ischemic stroke is an extremely common and dangerous pathology, it is important to use drugs with neuroprotective activity. The depth and degree of brain damage due to ischemia are reflected in its bioelectrical activity. This makes it possible to use the electrocorticography or intracranial electroencephalography (EEG) as a tool for evaluating the effectiveness of neuroprotective therapy. In the present study the neuroprotective properties of the experimental compound RU-1205 and the kappa-opioid agonist butorphanol were analyzed. The neuroprotective effect of the substances was assessed by measuring the extent of the neurological deficit and the changes in bioelectrical activity of the ischemic brain of rats. Compound RU-1205 (10 mg/kg, i.v.) as well as the reference drug butorphanol (2,5 mg/kg, i.v.) restored to normal neurological status and power of the EEG signal in delta and theta frequency bands.

Secondary Messengers – A Role in The Regulation of Cell Function

Secondary intermediaries, or secondary messengers, are intracellular signaling molecules released in response to stimulation of receptors. They are the initiating elements in many intracellular signaling cascades and cause the activation of primary effector messenger proteins. This triggers a cascade of physiological changes that are important for the growth, development, differentiation of cells, gene transcription, protein biosynthesis, secretion of hormones, neurotransmitters or cytokines, changes in bioelectric activity and cell migration, and apoptosis induction. Several universal secondary signaling systems exist in the cell, which are mediated by the main three types of mediators: hydrophobic molecules: water-insoluble molecules (diacylglycerol, phosphatidylinositol) that bind to cell membranes and diffuse across intermembrane spaces to organelle membranes, reaching and acting with membrane-bound secondary effector proteins; hydrophilic molecules: water-soluble molecules (cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), inositol triphosphate, calcium), which are distributed in the aqueous medium of the cytoplasm; gases: nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H2S), which pass through the cell membrane and diffuse into the cytoplasm. The purpose of this review is to generalize and systematize literature data on the mechanisms for the implementation of the functions of secondary messengers in the intercellular signaling system. The study of their functioning and regulation can serve as a fundamental basis for the study of normal brain and experimental pathology, creating the basis for subsequent clinical studies. Keywords: Secondary Mediators; Intercellular Signaling; Effector Proteins; Receptors; Ligands; Brain.

The Influence of Treadmill Training on the Bioelectrical Activity of the Lower Limb Muscles in Patients with Intermittent Claudication.

Aim: Intermittent claudication is the most common symptomatic manifestation of peripheral arterial disease (PAD), presenting as ischemic leg muscle pain and gait dysfunction. The aim of this study was to evaluate the changes in bioelectrical activity of the lower limb muscles activity in claudicating patients over a 12-week period of supervised treadmill training and to verify the hypothesis as to which muscles of lower limbs are activated by training treatment—the proximal, as compensatory mechanism, or the distal, which are the most ischemic. Methods: The study comprised 45 patients aged 60–70 years (height 168.8 ± 6.8 cm, weight 78.9 ± 9.2 kg) with PAD and unilateral intermittent claudication (Fontaine stage IIa/IIb), who participated in a 12-week supervised treadmill training program. Surface electromyography (sEMG) of the gastrocnemius lateralis (GaL), gastrocnemius medialis (GaM), tibialis anterior (TA), biceps femoris (BF), rectus femoris (RF) and gluteus medius (GM) muscles in the claudicated leg were continuously measured during the treadmill test. The average mean amplitude and mean amplitude range of the sEMG signal were analyzed. Results: During the treadmill test, after 12 weeks of training, the average mean amplitude of the GM (105 ± 43 vs. 74 ± 38%, p = 0.000008, ES = 0.76), BF (41 ± 22 vs. 33 ± 12%, p = 0.006, ES = 0.45) and GaM (134 ± 50 vs. 114 ± 30%, p = 0.007, ES = 0.48) muscles was significantly lower compared with baseline. The mean amplitude range was significantly decreased after 12 weeks of training in the GM (229 ± 64 vs. 181 ± 62%, p = 0.008, ES = 0.77) and BF (110 ± 69 vs. 84 ± 31%, p = 0.0002, ES = 0.48) muscles. After 12 weeks of training, the mean amplitude range of the TA muscle was significantly higher compared with baseline (104 ± 46 vs. 131 ± 53%, p = 0.001, ES = 0.54), but without significant changes in the average mean amplitude value. The most favorable changes, suggesting the lowest muscle fatigue and the highest walking capacity, were found in patients with the longest walking time. Conclusions: The obtained results may suggest that after 12 weeks of treadmill training, beneficial changes occurred in both the proximal and distal muscles. Therefore, greater foot plantar flexion and stronger push-off as well as greater hip extension may be considered the main mechanisms of observed gait pattern improvement. It may also be suggested that the therapy of gait alterations in patients with PAD should be focused not only on calf muscle pump improvement, but also on proximal hip extensor strengthening.

Electrophysiological brain functional network alterations associated with hippocampal volume in healthy and pathological aging

AbstractBackgroundThe early detection of Alzheimer disease is currently one of the main worldwide scientific goals. Estructural biomarkers, such as cortical deterioration and medial temporal lobe atrophy (MTLa), are well known and deeply studied. The relation of these structural changes with brain connectivity could help to understand the consequences of neurodegeneration in brain functioning, with the ultimate goal of explaining cognitive impairment. Magnetoencephalogram (MEG) quantitative analysis is a precise, non‐invasive tool to evaluate changes in bioelectrical activity of the brain. Therefore, it brings us the opportunity to study disruption of functional brain networks associated with changes in MTLa volume, as assessed with structural MRI.MethodWe recruited 376 healthy elders and 130 mild cognitive impairment patients (MCI) (aged from 61 to 85) from the “Hospital Universitario San Carlos” and the Center for elders at the Chamartín District, all located in Madrid, Spain. All of them underwent a neuropsychological evaluation, MRI assessment, and MEG recordings. The MCI diagnosis was established according to the NIA‐AA criteria. None of the participants exhibited a history of psychiatric or neurological disorders (other than MCI). We used a completely data‐driven approach to evaluate the relationship between functional connectivity (FC) and the hippocampal volume.ResultOur main finding was an augmented theta band functional connectivity (FC) in right temporal (RTemp) areas associated with lower hippocampal volume, and we found this FC signature to correlate negatively with memory performance. Furthermore, the average theta FC of this area differed significantly between groups, although the original relationship remained significant for each group independently. Finally, we performed a seed‐based analysis targeting the original right temporal region and found that the modulation of the theta FC was driven by connections to 1) superior frontal and 2) contralateral temporal areas.ConclusionThe results depict a clear FC pattern that seems to be associated with both healthy and pathological aging. This MEG signature may be useful as a non‐invasive biomarker for the progressive subcortical degeneration that occurs along aging, both healthy and pathological. Furthermore, it is also related with cognitive performance, especially with memory functioning.

СРАВНИТЕЛЬНАЯ ОЦЕНКА ПОКАЗАТЕЛЕЙ БИОЭЛЕКТРИЧЕСКОЙ АКТИВНОСТИ МЫШЦ У ПАЦИЕНТОВ СО СЪЕМНЫМИ ПОКРЫВНЫМИ ПРОТЕЗАМИ С ОПОРОЙ НА ИМПЛАНТАТЫ ПРИ ПОЛЬЗОВАНИИ В ТЕЧЕНИЕ 12 МЕСЯЦЕВ

Subject. A comparative assessment of the state of the stomatognathic system on the example of the bioelectrical activity of temporal and masticatory muscles in patients who used removable implant-supported overdentures with bar fixation system, made by two different methods: traditional and using digital methods of treatment planning and manufacturing was carried out.
 Objectives. To compare the changes of bioelectrical activity of temporal and masticatory muscles in patients with removable implant-supported overdentures made by two different methods: traditional and digital, who used dentures for a long time (12 months).
 Methods. Bioelectrical activity and symmetry of temporal and masseter muscles were investigated clinically by surface electromyography. Electromyography was performed in five probes: Rest, Light CO, Natural Swallowing, Maximal Volitional Clench (MVC) and Clench on Cotton Rolls (MVCCR).
 Results. In patients using overdentures produced in traditional way, no normal values of muscle activity were observed in any of the probes at the end of the study. In patients who used overdentures, made with the use of digital technologies, we noted a decrease of bioactivity of the muscles in the probes of Rest and Light CO, and an increase of biopotentials in the probes of MVC and MVCCR. The values obtained at the end of the study were characterized as normal or acceptable.
 Conclusions. The application of a digital method of treatment planning and fabrication of removable implant-supported overdentures with a bar fixation system allows to achieve more physiological values of temporal and masticatory muscles biopotentials, which can be interpreted as recovery of the functional integrity of the stomatognathic system.

The condition of bioelectrical activity of the brain among the patients suffering diabetes mellitus type II with hearing impairment

Topicality: The sensorineural hearing loss (SNHL) is a polyetiological disease with a complex pathogenesis. Sensorineural hearing loss is also caused by metabolic disorders and system diseases, including diabetes mellitus (DM).Quite often at sensorineural hearing loss there are extraauralic manifestations of the central nervous system (CNS). On the other hand, with diabetes, there are also observed the affection of the nervous system both in the form of polyneuropathy and certain disorders of the CNS. Electroencephalography (EEG) is a reliable, universal, objective, non-invasive method of research the functional condition of the CNS. Aim: to investigate changes in the condition of bioelectrical activity of the brain according to electroencephalography among patients with diabetes mellitus type II with impaired auditory function. Materials and methods: 43 patients with diabetes mellitus type II were examined, who, according to subjective audiometry, revealed impairments of auditory function and 15 persons of the control group. The EEG research was performed using a computer electroencephalograph from the company “DX-System” (Ukraine) according to the generally accepted method. Results and discussion: The qualitative analysis of EEG results among patients with diabetes revealed abnormalities in the functional condition of the CNS in the form of diffuse changes in bioelectrical activity of the brain, disorganization and desynchronization of basic rhythms, signs of irritation of brain structures, amplified by functional loads. Among the examined patients using background EEG we observed the expressed irritative changes, decrease in bioelectrical activity of a brain, desynchronization and disorganization of rhythms. Among many of them there were periodic sharp peaks and potentials, a tendency to accelerating the basic rhythm, and against this background, the increase in the content of slow waves (theta), mainly in the front leads. Moreover, the most pronounced changes in bioelectrical activity took place in the temporal and frontal leads. Thus, in patients with diabetes mellitus type II with SNHL disorganization and desynchronization of the EEG picture was detected in 34 patients (79.1 % cases). The expressed irritative changes were registered in 39 persons (90.6 % cases), hypersynchronous bursts were detected in 15 patients (34.8%), sharp peaks and potentials were present in 21 person (48.8 %) Many patients had smoothed zonal differences – 25 persons (58.1%) and lack of reaction to eye opening – 15 patients (34.8%)The decrease of bioelectrical activity reached 86.0 % cases. The amplitude of the basic alpha rhythm of the EEG among the examined patients diabetes mellitus type II with SNHL is significantly (p<0.01) lower than the norm in the temporal, parietal and occipital leads, which was 31.8±2.5, 44.1±3.1 and 43.5±4.2 мkV, respectively. In a significant part of the examined patients (88.3 %) with hearing impairments on the background of diabetes mellitus type II, these manifestations were increasing by hyperventilation. Violations of bioelectrical activity of the brain in 97.6% of cases were symmetrical, which indicates diffuse cerebral changes in the functional condition of the CNS in this category of patients. Irritations of the cortical structures of the brain were registered in all examined patients with diabetes mellitus type II. In many of these patients (97.6%) cortical irritation was combined with the involvement of deep brain structures. Thus, dysfunction of the diencephalic structures of the brain occurred in 48,8% of cases, diencephalic-stem – in 39,5%, mediobasal – in 9.3% cases. Only one patient had irritation of only the cortical structures. So, among our examined patients with diabetes mellitus type II with impaired auditory function according to EEG there are pronounced violations of bioelectrical activity according to EEG, including changes in the cortical and deep - diencephalic and stem structures of the brain. Conclusions: 1. The researches made by EEG method in patients with diabetes mellitus type II and SNHL objectively confirm the violation of the functional condition of the CNS among such patients. 2. In patients with diabetes mellitus type II and SNHL there are changes in bioelectrical activity mainly in the form of decreasing of bioelectrical activity of the brain (86,0%), expressed irritative changes (90.6%), irritation of deep structures of the brain (97,6), disorganization and desynchronization of the EEG picture (79.1% cases). 3. In patients with SNHL on the background of diabetes mellitus type II there is significantly (p<0.01) lower decreasing of amplitude of the alpha rhythm in comparison with the control values in temporal, parietal and occipital leads to 31.8±2.5, 44.1±3.1 and 43.5±4.2 mkV, respectively.

COMPARATIVE ANALYSIS OF NEUROPHYSIOLOGICAL FEATURES IN YOUNG WOMEN AND MEN SUFFERING FROM EPILEPSY

The definition of epilepsy via the concept of neuronal discharge indicates the crucial importance of electroencephalography (EEG) in epileptology. This pathology is a certain problem for each sex, that requires gender−specific approaches when managing and treating such patients. To investigate them, 30 men and 30 women aged 18−44 years with a reliable diagnosis of epilepsy were examined. A comprehensive clinical, neurological and neurophysiological study of patients was performed, taking into account the data of clinical case and life history. Each patient was assessed for neurological status according to traditional methods, electrophysiological method of examination (routine EEG) was used. On the results of electroencephalography in individuals of both sexes with epilepsy, there was a decrease in the amplitude of the α−rhythm, but a significant slowdown in this rhythm was not detected. Most patients had high−amplitude (> 20 μV) and low−frequency β1−rhythm. Low−frequency high−amplitude slow−wave activity was regarded as an EEG reflection of degenerative−dystrophic processes in brain. Photostimulation caused paroxysms of bilaterally synchronous sharp and slow waves, complexes of "acute−slow" wave. Hyperventilation led to an increase in the θ−rhythm amplitude, appearance of δ−waves, higher expression of true epileptiform phenomena: adhesions, "acute wave−slow wave" complexes, "spike−slow wave" complexes. A comparative analysis of the obtained results allowed to conclude that the changes in bioelectrical activity in epilepsy occur according to the general mechanisms of epileptogenesis, regardless of gender. Key words: epilepsy, electroencephalogram, comparative analysis, young men and women.

Characteristics of Cognitive Impairments in Alcoholic and Dyscirculatory Encephalopathies

Objective. To identify the features of cognitive impairments (CI) in patients with alcoholic (AE) and dyscirculatory (DE) encephalopathies. Materials and methods. The study included 32 patients with DE and 30 with AE. Along with clinical observations, patients underwent computerized electroencephalography (EEG), recording of cognitive event-related potentials, and neuropsychological testing. Results and conclusions. The pathologies studied here showed both common and distinct signs in the clinical picture, in the emotional-personality domain, and impairments to cognitive processes. Common features of encephalopathies of different etiologies were CI and asthenic syndrome; AE was characterized by hyposthenic and DE by mixed (hyper- and hyposthenic) syndromes. The EEG showed that changes in bioelectrical activity in DE were predominantly located in the occipital-parietal areas of the cortex, while in AE they were located in the temporal and occipital-parietal areas. CI in DE and AE consisted of disorders to categorial thinking, long-term memory, reciprocal coordination, and digital gnosis, pointing to dysfunction of the frontal and parietal lobes of the left hemisphere, hippocampus, and corpus callosum. The indexes of the δ, β1, and β2 rhythms were discriminating features of CI in AE and DE.

Changes in cardiovascular indices and bioelectric activity of the brain in response to cold exposure in young men

The aim was to study changes in cardiovascular indices and electroencephalogram (EEG) characteristics in response to short-term general air cooling of the body in young adults. Methods. The sample consisted of 13 healthy men aged 18-21 years who were permanent residents of the city of Arkhangelsk (Northwest Russia). The spectral power (SP) of EEG rhythms was assessed using an electroencephalograph (Neurosoft, Russia). Heart rate variability (HRV) was measured using Varikard equipment (Ramena, Russia). Temperature of the skin surface was measured with an electronic infrared thermometer B Well WF - 1000 (Switzerland). Blood pressure were recorded with an automatic tonometer A&D Medical UA-668 (Japan). All indicators were measured prior to the exposure, under cold exposure in the cold chamber "USF-25N" (-20C, 10 minutes) and 5 and 10 minutes after the exposure. Results. Two types of changes in the study parameters were identified. In type I reaction there was is a greater decrease in body surface temperature, an increase in blood pressure (BP), HRV indicators (RMSSD, pNN50%, TP) and minimal changes in the bioelectrical activity of the brain during the exposure. During the recovery period, systolic BP did not decrease and HRV indicators recovered slowly. In type II reaction, there was a smaller decrease in body surface temperature, an increase in the а-0 activity of the EEG in the anterotemporal regions of the brain and an increase in the 0-activity of the EEG in the frontal regions on the right combined with a increase in HRV (SDNN, pNN50%, RMSSD, TP), an increase in BP during exposure with return to initial values after the exposure. Conclusions. We identified two types of reactions to cold exposure in young men that may reflect the heterogeneity of adaptive reactions of the body's regulatory systems to cold.

ELECTROENCEPHALOGRAPHIC MARKERS OF LATERAL SHIFTS OF BRAIN MIDLINE STRUCTURES IN PATIENTS WITH ACUTE SPONTANEOUS SUPRATENTORIAL INTRACEREBRAL HAEMORRHAGE

The aim of this study is to improve the diagnostic approaches in acute period of spontaneous supratentorial intracerebral hemorrhage by detecting the most informative parameters of spectral analysis of the electroencephalographic pattern in the evaluation of cerebral bioelectrical activity changes caused by the lateral shifts of brain midline structures. Materials and methods. We carried out clinical and paraclinical examination of 156 patients (90 men and 66 women, mean age 66,7±0,8 years) with firstly appeared hypertensive spontaneous supratentorial intracerebral hemorrhage. The diagnosis was based on the findings of computed tomography. Lateral shift was evaluated as an average from septum pellucidum and pineal gland displacements. Clinical neurological investigation included the evaluation according to the National Institute of Health Stroke Scale. Computed electroencephalography was carried out within the first 48 hours from the disease onset. Spectral rhythm power, fronto-occipital gradients, interhemispheric rhythm asymmetry parameters were analyzed. Statistical processing included evaluating differences between the groups studied, logistic regression analysis, ROC-analysis. Results. No lateral shift of brain midline structure was found in 57 (36.5%) patients; lateral shift ranged from 1-5mm was diagnosed in 72 (46.2%) patients; the lateral shift over 5 mm was found in 27 (17.3%) patients. We have found out the following values can be used as electroencephalographic criteria of lateral shift of brain midline structures: values of relative spectral power rhythm of alpha band ≤20,5% in affected hemisphere (Se=79,8%, Sp=77,2%) and ≤17,7% in intact hemisphere (Se=71,7%, 75,4%), fronto-occipital rhythm gradients of alpha2 band >–0,085 in affected hemisphere (Se=71,7%, Sp=63,2%) and >–0,266 in intact hemisphere (Se=80,8%, Sp=54,4%), while relative spectral rhythm power of delta band >48,4% in affected hemisphere (Se=88,9%, Sp=74,2%) and >46,8% in intact hemisphere (Se=92,6%, Sp=72,4%), fronto-occipital rhythm gradients of alpha band >–0,001 in affected hemisphere (Se=81,5%, Sp=65,1%). These values demonstrate disturbances in cerebral bioelectrical activity caused by lateral shift over 5 mm. Conclusions. The values of relative spectral rhythm power and fronto-occipital rhythm gradients of alpha band in affected and intact hemispheres are the most informative parameters of spectral electroencephalographic pattern analysis for detection of bioelectrical brain activity deteriorations caused by the lateral shift of brain midline structure due to acute spontaneous supratentorial intracerebral haemorrhage.

FEATURES OF CEREBRAL CIRCULATORY DYNAMICS AND CEREBRAL BIOELECTRIC ACTIVITY IN CHILDREN WITH CRANIOCEREBRAL INJURY

In order to study the state of cerebral hemodynamics and to investigate the electroencephalographic characteristics in children with closed traumatic brain injury, 114 patients were examined. The children were examined in 6.1±0.8 months after a traumatic brain injury. To determine cerebral hemodynamics, transcranial dopplerography was performed, the functional state of brain was evaluated according to electroencephalography. In the course of the study, it was noted that a disordered cerebral hemodynamics in children with moderate and severe brain contusion and its foci presence was accompanied by a rise in a linear velocity of blood flow, while its decrease was found at the same contusion, but that was severe and with the presence of subdural, subarachnoid and epidural hemorrhage. Signs of diffuse changes in bioelectrical activity of the brain were represented by a significant increase in an amplitude of the alpha rhythm in children with closed traumatic brain injury of moderate and serious severities compared to mild one. Key words: children, craniocerebral injury, electroencephalography, transcranial Doppler sonography, paroxysmal activity.

Биоэлектрическая активность головного мозга у детей с острым вирусным энцефалитом

Aim of our study was to evaluate changes of bioelectrical activity in children with acute viral encephalitis. The study involved 26 children delivered to The Pediatric Research and Clinical Center for Infectious Diseases of the Federal Medical and Biological Agency of Russia with a clinically established diagnosis of viral encephalitis. Boys prevailed in the ratio of 18:8, the average age of the group was 12 ± 2.1 years. All patients were enrolled in the study in the first 14 days of acute viral encephalitis; an EEG analysis of 10 healthy children was performed as a comparison group. All patients were registered EEG with the Neuron Spectrum 5 Encephalograph (Russia, Ivanovo), then a visual and spectral analysis of the frequencies were performed. The spectral power of the α-, δ- and θ-rhythms were analyzed, as well as α/δ and α/θ ratios.Visual analysis of EEG in 100% of cases in children in the acute period of viral encephalitis recorded diffuse slowdown with the registration of delta and theta waves. Focal changes in the form of sharp waves were recorded in 85% of cases (21 patients). Periodic activity in the examined group of patients was not registered in any case. A quantitative analysis based on the results of statistical processing revealed a statistically significant decrease in the ratio of α/θ (p = 0.035), maximal spectral power of α (p = 0.046) and minimal of θ (p = 0.044) in children with encephalitis compared with a group of healthy children. Conclusion: In children with viral encephalitis in its acute period significant disruption of normal distribution and power of α- and θ-rhythms is seen. This disruption may be characterized as lowering of the power of both rhythms. We may suppose, that these changes are the result of the inhibition of the thalamus and reticular formation functional activity.

DYNAMICS OF NEUROMUSCULAR ACTIVITY IN PATIENTS WITH LOCAL COLD INJURY

The OBJECTIVE was to study the changes of bioelectric activity of muscles in patients with local cold injury of the feet.MATERIAL AND METHODS. Non-invasive method of cutaneous electroneuromyography was used to evaluate the bioelectrical activity of muscles. The study was conducted in 52 patients with local cold injury of III–IV degree of the lower extremities of the late reactive period and the period of granulation and epithelialization. M-response amplitude, residual latency and propagation velocity of the excitation were estimated.RESULTS. In patients with local cold injury, there was a decrease in the bioelectric activity of the limb muscles proximal to the affected area. M-response amplitude and the propagation velocity of the excitation decreased in the patients in the late reactive period, while the residual latency increased. In patients with frostbite limbs during granulation and epithelialization, there was a tendency to restore the level of bioelectrical activity of muscles relative to the late reactive period.CONCLUSION. The basis of the adverse effects of local cold injury was “chronic” endothelial dysfunction and local neuropathy.The authors declare no conflict of interest.The authors confirm that they respect the rights of the people participated in the study, including obtaining informed consent when it is necessary, and the rules of treatment of animals when they are used in the study. Author Guidelines contains the detailed information.

Results of fundamental studies of the East Siberian Institute of medical and environmental studies on the main problems of occupational health and human ecology (to the 60th anniversary of the Institute)

The solution of modern problems of occupational health and human ecology not only gives the possibility of implementating measures aimed at improving the health of workers, but also determines the future quality of life of the population. Implementation of basic research focused on the study of the pathogenesis of leading occupational and environmentally related diseases, and the development of scientific and practical measures to improve methods of diagnosis, treatment and prevention remain the main activities of the Institute and meet the priorities of the strategy of scientific and technological development of the country and the key objectives of Decree of the President of the Russian Federation from May 7, 2018.The results of long-term studies of the Institute on the infl uence of a number of toxicants (mercury, lead, vinyl chloride and a complex of toxic neurotropic substances formed in fi res) allowed for the fi rst time to develop scientifi c and methodological bases for modeling toxic encephalopathy. Th e features of the formation of violations of bioelectric activity of the brain, revealed violations of metabolic and myogenic mechanisms of regulation of cerebral blood fl ow and elastic-tonic properties of arteries. Studies have allowed to develop a classifi cation of intoxication complex neurotropic toxic substances, methods of predicting their development. Presents a study of possibility of formation in persons with chronic mercury intoxication as an independent professional disease — ophthalmoergonomics. Proved the concept of autoimmunological progressive course occupational toxic encephalopathy. For the fi rst time it was established that silver nanoparticles encapsulated in a natural polymer matrix — arabinogalactan — can penetrate the blood-brain barrier and persist for a long time in the nervous tissue, causing progressive morphological and functional disorders of its cellular and intracellular organization. Th e necessity to develop new methodological approaches to the assessment of safety. An experimental model for the evaluation of neurotoxic properties of nanocomposites has been developed.When studying the eff ect of vibration on the body, it was found that in patients with vibration disease in the post-contact period (aft er the termination of work with a vibration tool), previously formed foci of pathological activity and changes in bioelectric activity with interhemispheric asymmetry persist for a long time. Th e General regularities of changes in the Central aff erent conductive structures and peripheral nerves caused by neurochemical shift s in certain specialized structures of the nervous tissue were establis hed. Th e article presents materials on the impact of industrial emissions on the morbidity of children. When studying the response of the adaptive reactions of the organism to the immune chronic exposure revealed the gradual changes in the indices of immunity.