Extended Frequency Range Research Articles

Resonant frequencies of multi-layer building constructions: Estimation by measurement of acceleration amplitudes

The Austrian building regulation requirements for impact sound insulation are based on the weighted standardized impact sound pressure level as single-number specification. In recent years, it has become apparent that not only the single-number specification, but the extended frequency range and frequency characteristics of impact sound insulation of constructions can have noticeable influence on the perceived acoustic performance of a construction. Therefore, the Austrian Classification Standard ÖNORM B 8115-5: 2021-04 includes extended requirements on impact sound insulation. It provides two ways for verification of the sound insulation classes A to C. One way is the verification via the resonance frequency of multi-layer constructions. However, there exist as yet no standardized measurement methods for the estimation of the resonance frequency of multi-layer building constructions. In response, in course of this study a new measurement method for the estimation of the resonance frequencies of multi-layer constructions was developed. For this development acceleration measurements were carried out on both surfaces of particularly double-layer building constructions, that were excited with a rubber hammer. From these measurement results, in conjunction with an analytical model, it was possible to derive a measurement method for estimating the resonant frequency via the frequency characteristics of the acceleration amplitudes.

A simple electrical circuit model for impedance spectroscopy with cochlear implant electrodes

Although cochlear implants are an established method of restoring hearing, they can have limitations such as increasing current spread and decreasing frequency resolution due to tissue growth around the electrode array. Impedance measurements in cochlear implants have become a versatile tool for intra- and post-operative diagnosis of cochlear implant state. However, most clinical devices use current pulse stimulation already available in the implants and analyze the voltage response in the time-domain and spread along the cochlea. To use the full potential of impedance spectroscopy in differentiating cell types, measurement over an extended frequency range is required. This study presents a simple electrical equivalent circuit for impedance spectroscopy with cochlear implants in a 2-pole configuration. The electrical equivalent circuit describes the electrical properties of the cochlear implant electrode and its electrochemical behavior at the electrode-electrolyte interface by comparing two non-linear bilayer models, Cole-Cole and Schwan-Faraday. The model is validated for four cochlear implant electrodes from four different manufacturers (MED-EL FlexSoft, AB HiFocus SlimJ, Oticon EVO, Cochlear Nucleus CI622) characterized by impedance spectroscopy between 5 Hz and 13 MHz. In the future, this electrical equivalent circuit may help to extract parameters for differentiating cell types around the cochlear implant electrode from an impedance spectroscopic measurement.

Study of the State Primary Measurement Standard of the Unit of Phase Shift Angle Between Two Voltages

Phase measurements are necessary for determining main parameters of the oscillatory process in complex electrical networks. Most often, it is precisely the phase shift angle (PSA) between two oscillatory processes of the same frequency that is measured. An essential indicator of the quality of electrical energy is the coefficient of asymmetry in a three-phase electrical network, which depends on the load of consumers in this network. This indicator is affected by a short circuit between two phase voltages. Phase measurement standards, phase meters, and phase converters are included in the measuring equipment for phase measurements. They are widely used in such fields as radiolocation, radio navigation, non-destructive testing, radio engineering, telecommunications, acoustics, metallurgy, machine and aircraft industry, space industry, as well as in scientific research and defence. The State Measurement Standard of Ukraine of the PSA unit between two voltages in the frequency range from 0.01 Hz to 10 MHz is maintained at the State Enterprise “UKRMETRTESTSTANDARD”, Kyiv. It provides metrological traceability of phases measured in the country. The main components of the standard were calibrated at the PTB, the National Metrology Institute of Germany. In Ukraine, numerous measurement standards and measurement instruments for phase measurements (more than 500.000 units) are used, in particular, phase calibrators, phase meters, phase shifters, synchronoscopes etc. Regular study of metrological characteristics of the DETU 09-07-11 measurement standard is conducted both in the main (from 5 Hz to 200 kHz) and in the extended (from 0.01 Hz to 10 MHz) frequency range. The PSA values obtained as a result of the research in the main frequency range do not exceed 0.001° (which is maximum according to measurements at all calibration points 0.00015°), and in the extended frequency range – 0.01° (which is maximum according to measurements at all calibration points 0.0053°). To eliminate the systematic measurement uncertainty component of the phase measurement standard, a special calibration is regularly performed using a set of resistive and capacitive phase bridges.

IRMPD spectroscopy of deprotonated selenocysteine - The 21st proteinogenic amino acid

The effect of deprotonation on the structure and stability of the 21st proteinogenic amino acid selenocysteine, generated as bare deprotonated species by electrospray ionization, has been investigated by infrared multiple photon dissociation (IRMPD) spectroscopy over an extended frequency range (700-3600 cm−1), encompassing both the fingerprint and X–H (X = C, N, O) stretching ranges. IRMPD spectra, interpreted by anharmonic DFT calculations, provide evidence of a thermally averaged ion population of two types of low-lying canonical conformers deprotonated at the selenol (Se–H) group and involved in different H-bonding motifs.The broadened and diffuse band structures observed in the H-stretching range are well interpreted by Born-Oppenheimer molecular dynamics computations that provide a valuable description of the flexible backbone arrangements of Sec and of the proton sharing dynamics in the Se–HO and Se–HN moieties.Other prototropic isomers, deprotonated at the carboxylic group or with a zwitterionic structure, should not be significantly populated, according to their higher free energy and calculated IR spectra inconsistent with experimental evidence.

Quantum Cascade Laser Infrared Spectroscopy for Glycan Analysis of Glycoprotein Solutions.

Glycans are oligosaccharides attached to proteins or lipids and affect their functions, such as drug efficacy, structural contribution, metabolism, immunogenicity, and molecular recognition. Conventional glycosylation analysis has relied on destructive, slow, system-sensitive methods, including enzymatic reactions, chromatography, fluorescence labeling, and mass spectrometry. Herein, we propose quantum cascade laser (QCL) infrared (IR) spectroscopy as a rapid, nondestructive method to quantify glycans and their monosaccharide composition. Previously, we demonstrated high-sensitivity IR spectroscopy of protein solution using solvent absorption compensation (SAC) and double-beam modulation (DBM) techniques. However, the SAC-DBM approach suffered a limited frequency scanning range (<400 cm-1) due to the light dispersion by acousto-optic modulators (AOMs). Here, we implemented a mirror-based double-pass AOM in the SAC-DBM scheme and successfully extended the frequency range to (970 to 1840 cm-1), which encompasses the vibrational fingerprint of biomolecules. The extended frequency range allowed the simultaneous observation of monosaccharide ring bands (1000 to 1200 cm-1) and protein amide bands (1500 to 1700 cm-1). We compared the IR spectra of six glycoproteins and two nonglycosylated proteins with the results from intact mass spectrometry. The IR absorbance ratios of the ring band to the amide band of glycoproteins in solutions showed a linear correlation with the ratios of glycan to protein backbone masses. Furthermore, a multivariate analysis produced monosaccharide compositions consistent with the reported database for the glycoproteins, and the monosaccharide compositions were used to improve the predictability of the glycan-protein mass ratio from the IR-absorbance ratio. This nondestructive, high-sensitivity QCL-IR spectroscopy could be used as a standard method to monitor batch-to-batch comparability during drug manufacturing and quantify the glycosylation and monosaccharide composition of new glycoproteins and other glycosylated biosystems.

Science development study for the Atacama Large Aperture Submillimeter Telescope (AtLAST): Solar and stellar observations.

Observations at (sub-)millimeter wavelengths offer a complementary perspective on our Sun and other stars, offering significant insights into both the thermal and magnetic composition of their chromospheres. Despite the fundamental progress in (sub-)millimeter observations of the Sun, some important aspects require diagnostic capabilities that are not offered by existing observatories. In particular, simultaneously observations of the radiation continuum across an extended frequency range would facilitate the mapping of different layers and thus ultimately the 3D structure of the solar atmosphere. Mapping large regions on the Sun or even the whole solar disk at a very high temporal cadence would be crucial for systematically detecting and following the temporal evolution of flares, while synoptic observations, i.e., daily maps, over periods of years would provide an unprecedented view of the solar activity cycle in this wavelength regime. As our Sun is a fundamental reference for studying the atmospheres of active main sequence stars, observing the Sun and other stars with the same instrument would unlock the enormous diagnostic potential for understanding stellar activity and its impact on exoplanets. The Atacama Large Aperture Submillimeter Telescope (AtLAST), a single-dish telescope with 50m aperture proposed to be built in the Atacama desert in Chile, would be able to provide these observational capabilities. Equipped with a large number of detector elements for probing the radiation continuum across a wide frequency range, AtLAST would address a wide range of scientific topics including the thermal structure and heating of the solar chromosphere, flares and prominences, and the solar activity cycle. In this white paper, the key science cases and their technical requirements for AtLAST are discussed.

Formation of complex discrete samples for electrocardiogram isoline drift extraction devices

In the automatic analysis of an electrocardiosignal, in order to adequately assess its amplitude parameters, it is necessary to ensure that there is no isoline drift in the signal. The direct removal of the isoline drift using a high-pass filter leads to distortion of the shape and amplitude parameters of the electrocardiosignal elements. When extracting the isoline drift based on interpolation of samples on the PQ segment, the frequency of the extracted isoline drift signal cannot even theoretically exceed half the heart rate, but in reality it is an order of magnitude less. The purpose is to develop a device for the formation of complex discrete samples of the electrocardiosignal, ensuring the isolation without loss of informative components of the electrocardiosignal of the isoline drift with a frequency range comparable to the heart rate, in conditions of variability of the sampling frequency due to heart rate variability. The possibility of expanding the frequency range of the isoline drift signal isolated from the electrocardiosignal based on the real-time transformation of isoline drift samples taken at the TP interval into complex discrete samples has been substantiated. When forming complex discrete samples, the variability of the sampling period due to heart rate variability is taken into account. A device for forming complex discrete samples of the isoline drift signal has been proposed, allowing extraction of isoline drift with an extended frequency range without loss the informative components of the electrocardiosignal. The developed device can be used both directly as part of mobile electrocardiographs designed to monitor a person's ECG in the conditions of his daily activities, and in equipment for processing daily electrocardiograms before analyzing their parameters.

Wind turbine rotors in surge motion: new insights into unsteady aerodynamics of floating offshore wind turbines (FOWTs) from experiments and simulations

Abstract. An accurate prediction of the unsteady loads acting on floating offshore wind turbines (FOWTs) under consideration of wave excitation is crucial for a resource-efficient turbine design. Despite a considerable number of simulation studies in this area, it is still not fully understood which unsteady aerodynamic phenomena have a notable influence on the loads acting on a wind turbine rotor in motion. In the present study, investigations are carried out to evaluate the most relevant unsteady aerodynamic phenomena for a wind turbine rotor in surge motion. As a result, inflow conditions are determined for which a significant influence of these phenomena on the rotor loads can be expected. The experimental and numerical investigations are conducted on a two-bladed wind turbine rotor subjected to a tower-top surge motion. A specialised wind tunnel test rig has been developed to measure the aerodynamic torque response of the rotor subjected to surge motions with moderate frequencies. The torque measurements are compared to two free-vortex-wake (FVW) methods, namely a panel method and a lifting-line method. Unsteady contributions that cannot be captured using quasi-steady modelling have not been detected in either the measurements or the simulations in the covered region of motions ranging from a rotor reduced frequency of 0.55 to 1.09 and with motion velocity amplitudes of up to 9 % of the wind speed. The surge motion frequencies were limited to a moderate range (5 to 10 Hz) due to vibrations occurring in the experiments. Therefore, a numerical study with an extended range of motion frequencies using the panel and the lifting-line method was performed. The results from both FVW methods reveal significant unsteady contributions of the surge motions to the torque and thrust response that have not been reported in the recent literature. Furthermore, the results show the presence of the returning wake effect, which is known from helicopter aerodynamics. Additional simulations of the UNAFLOW scale model and the IEA 15 MW rotor demonstrate that the occurrence of the returning wake effect is independent from the turbine but determined by the ratio of 3P and surge motion frequency. In the case of the IEA 15 MW rotor, a notable impact of the returning wake effect was found at surge motion frequencies in the range of typical wave periods. Finally, a comparison with OpenFAST simulations reveals notable differences in the modelling of the unsteady aerodynamic behaviour in comparison to the FVW methods.

Extended Frequency Range Operation for Cascaded MMC and Cycloconverter-Based Machine Drive System

Extended Frequency Range Operation for Cascaded MMC and Cycloconverter-Based Machine Drive System

Mirror-based multimodal straightforward method for impedance eduction using a zigzag array

The Mirror-based Multimodal StraightForward Method (MM-SFM) is proposed herein to realize accurate and reliable liner impedance eduction covering the wide frequency range of aeroengine fan noises. It adopts a novel zigzag array in the flow duct, and unfolds them by a coordinate transformation into a mapping diagonal array in an extended duct, which can increase the array transverse spacing Δz considerably. Then, it invokes the M-SFM incorporating the trust-region and extended Prony's algorithms, to decompose the three-dimensional multimodal aeroacoustic field and educe the impedance. A parametric study based on the Monte-Carlo uncertainty analysis is conducted through finite-element numerical experiments on a 51 × 51 mm2 flow duct, to survey the method performance under random perturbations. It indicates that, the educing accuracy and reliability are promoted by increasing Δz or the axial spacing Δx properly, and the decomposed-mode number M×N=10 is appropriate herein. In our studied cases, using the recommended array of Δz=25.5mm and Δx=22mm locating at the nodes of transverse mode m = 2, the MM-SFM generally produces accurate averaged educed impedances in a considerably extended frequency range from 100 Hz up to nearly 10 kHz, and has small educing uncertainties at most absorptive frequencies and thus a good reliability.

Performances of low frequency impact sound in wooden buildings

Since 1999 Sweden has required an extended frequency range for sound insulation in residential buildings, using 50 Hz as the lower limit. This regulation update has driven the design and development of multi storey residential building systems with wooden structures in a positive direction. Already in the mid 1980'ies there existed scientific proof that it the perceived impact sound will improve if the frequency range was extended below the lower standard limit 100 Hz at that time. Lately, researchers have indicated that the perceived impact sound can be even further improved if the frequency range is extended below current lower standardized limit of 50 Hz. Assume that the frequency range for impact sound requirement will be further extended to include frequencies from 25 Hz, what would that mean for modern wooden apartment buildings? Acouwood and Kuster &amp; Partner AG are collecting data from 20 Hz, no matter if the standard measurement procedure cannot be applied below 50 Hz. It gives a good overview of potential annoyance risk but also of acoustic performances of modern sustainable multifamily buildings and how they can be improved. This paper summarizes measurement results of impact sound from 20 Hz in several wooden buildings.

Stabilization against gravity and self-tuning of an elastic variable-length rod through an oscillating sliding sleeve

An elastic rod, straight in its undeformed state, has a mass attached at one end and a variable length, due to a constraint at the other end by a frictionless sliding sleeve. The constraint is arranged with the sliding direction parallel to a gravity field, in a way that the rod can freely slip inside of the sleeve, when the latter is not moving. In this case, the free fall of the mass continues until the rod is completely injected into the constraint. However, when the sliding sleeve is subject to a harmonic transverse vibration, it is shown that the fall of the mass and the rod injection are hindered by the presence of a configurational force developing at the sliding sleeve and acting oppositely to gravity. During the dynamic motion, such a configurational force is varying in time because it is associated with the variable bending moment at the sleeve entrance. It is (experimentally, analytically, and numerically) demonstrated that, in addition to the states of complete injection or ejection of the elastic rod (for which the mass falls down or is thrown out), a stable sustained oscillation around a finite height can be realized. This ‘suspended motion’ is the signature of a new attractor, that arises by the constraint oscillation. This behaviour shares similarities with parametric oscillators, as for instance the Kapitza inverted pendulum. However, differently from the classical parametric oscillators, the ‘suspended’ configuration of the rod violates equilibrium and the stabilization occurs through a transverse mechanical input, instead of a longitudinal one. By varying the sliding sleeve oscillation amplitude and frequency within specific sets of values, the system spontaneously adjusts the sustained motion through a self-tuning of the rod’s external length. This self-tuning property opens the way to the design of vibration-based devices with extended frequency range.

The phase shift of the envelope-following response as an indicator of the traveling wave propagation in the beluga cochlea

Auditory system of the toothed whales features a number of modifications that allow to adapt to aquatic life and echolocation. One of unanswered questions is how the characteristics of the traveling wave changed due to extension of frequency range. We hypothesize that the phase shift of the envelope-following response (EFR) reflects the traveling wave propagation along the basilar membrane in the cochlea. EFRs were non-invasively recorded in the beluga whale. The sound stimuli were tone burst of carrier frequencies of 16 to 128 kHz and envelope frequency of 1 kHz. Thus, all EFR contained the fluctuations with 1 kHz frequency. The EFR phase shift depended on the carrier frequency and the sound intensity: the higher intensity and frequency, the greater the phase shift. If it is accepted that at the EFR threshold the phase depends only on the carrier frequency, the phase shift allows to calculate the time of the traveling wave propagation along the basilar membrane. The travelling wave time between the regions corresponding to 16 and 128 kHz was approximately 0.8 ms.

Parameter identification method of nonuniform and under-sampled blade tip timing based on extended DFT and compressed sensing

Vibration amplitude and frequency are the two most important indicators that characterize the health status of high-speed rotating blades, but the signal obtained by blade tip timing (BTT) technology, one of the best rotating blade vibration monitoring methods, is seriously nonuniform and under-sampled, which makes these two indicators difficult to identify. In view of this problem, the paper proposes a parameter identification method for the nonuniform and under-sampled BTT signal based on extended Discrete Fourier transform and compressed sensing (CS), with the Fourier integral transformation as the goal. It realizes the frequency analysis of nonuniform under-sampled signals by constructing and optimizing the transformation basis function instead of the exponential basis in the traditional FFT transformation in the extended frequency range, and then constructs a CS model through the obtained blade vibration frequency. The complete waveform of the blade vibration is restored by using a small number of under-sampled signals, thus obtaining the blade vibration amplitude and vibration frequency. On the one hand, the method proposed in this paper breaks through the limitation of Nyquist’s sampling theorem, and the number of analytical spectral lines is no longer limited to the number of sampling points, which improves the frequency resolution. On the other hand, only a small number of measurement signals can be reconstructed to achieve a complete vibration signal. The feasibility and reliability of the proposed method are verified by mathematical modeling, simulation analysis, and experimental testing. The results indicate that when the number of sensors is greater than or equal to four, the time domain and frequency domain signals of blade vibration can be accurately analyzed based on the proposed method, the vibration amplitude error is less than 0.01 mm, the frequency error is less than 0.1 Hz, and it has good anti-interference performance.

Anisotropy and Frequency Dependence of Signal Propagation in the Cerebellar Circuit Revealed by High-Density Multielectrode Array Recordings.

The cerebellum is one of the most connected structures of the central nervous system and receives inputs over an extended frequency range. Nevertheless, the frequency dependence of cerebellar cortical processing remains elusive. In this work, we characterized cerebellar cortex responsiveness to mossy fibers activation at different frequencies and reconstructed the spread of activity in the sagittal and coronal planes of acute mouse cerebellar slices using a high-throughput high-density multielectrode array (HD-MEA). The enhanced spatiotemporal resolution of HD-MEA revealed the frequency dependence and spatial anisotropy of cerebellar activation. Mossy fiber inputs reached the Purkinje cell layer even at the lowest frequencies, but the efficiency of transmission increased at higher frequencies. These properties, which are likely to descend from the topographic organization of local inhibition, intrinsic electroresponsiveness, and short-term synaptic plasticity, are critical elements that have to be taken into consideration to define the computational properties of the cerebellar cortex and its pathological alterations.

Physically consistent testing of large-frequency-band magnetic losses of non-oriented electric steel considering dynamic anisotropy

Non-oriented (NO) magnetic steels show gradually increasing relevance over an extended range of frequencies, in particular for electric drives. However, until now, data for corresponding characteristics like losses P are available in very restricted ways. A reason is that loss testers are standardized for technical low frequency (LF) until now. Here we report detailed loss data for three steel types, tested by broad-band single sheet testers that offer tests up to high frequency (HF), for values of f = 10 kHz, for steel samples of 500 × 170 mm2 (or 500 mm). In solving a specific problem of NO steel, very high values of H of magnetic field strength are considered by “True Field Air Flux Compensation.” For rising f, the three steels show strong, non-linear increases in losses P, up to about 100 W/kg. With respect to anisotropy, corresponding factors were defined for rolling direction and transverse direction (TD). The effective “field anisotropy” AH tends to show high values for LF but sinks dramatically for HF due to strong eddy currents. The analogously defined “loss anisotropy” AP is lower a priori. In addition, decreases in HF are less pronounced. The International Electrotechnical Commission-standardized “loss anisotropy factor” is generally lower by more than a factor of two, with values up to 30% for LF that may sink to zero for HF due to eddy current mechanisms that are rather independent from crystalline texture. In conclusion, for high dynamics, the effective anisotropy deviates completely from LF-based texture characteristics. Additional analyses of power functions prove that during a period of magnetization, strong anisotropy exists with respect to alignments of atomic moments, in particular for the TD.

Measuring Installation for the Research of Errors of Measuring Current Transformers in the Extended Frequency Range 40–2500 Hz

Measuring Installation for the Research of Errors of Measuring Current Transformers in the Extended Frequency Range 40–2500 Hz

METHODOLOGICAL ASPECTS OF LUNG ACOUSTIC IMPEDANSOMETRY

Background. The pandemic caused by a new coronavirus infection has determined the relevance of the development of non-invasive methods for express examination of the function of external respiration in the interests of medical diagnostics and development of personal protective equipment against infectious diseases transmitted by airborne droplets.&#x0D; Purpose. The purpose was to study the possibility of increasing the information content of diagnosing the state of the respiratory system by measuring the acoustic impedance using the modernized two-microphone method.&#x0D; Materials and methods. An experimental study of the impedance and biophysical characteristics of the lungs was carried out on groups of healthy (12 heads) and patients with pneumonia (7 heads) male rabbits weighing 2.5-3 kg. To study the acoustic characteristics of the lungs, a direct method of impedancemetry based on a two-microphone measurement technique was used; the determination of the biophysical parameters of the lungs is based on measuring their weight and volume.&#x0D; Results. The fact of an increase in active energy losses of low-frequency acoustic oscillations during their propagation in the respiratory system has been experimentally established, which makes it possible to create an informative criterion for diagnosing its condition. When examining healthy lungs using acoustic impedancemetry, the active energy loss of acoustic vibrations at low frequencies should not differ significantly from the corresponding values of the energy loss of such vibrations at the resonant frequency. In case of violations of the conductivity of the airways or in the presence of exudate in the lungs, active losses at low frequencies will significantly exceed losses at the resonant frequency: the worse the condition of the lungs, the higher the losses. It has been established that the presence in the lungs of a cavity with its own resonant frequency leads to a decrease in the resistance of the respiratory system at these frequencies.&#x0D; Conclusion. The experimentally recorded fact of a decrease in resistance at frequencies below the resonant frequency of the respiratory system makes it possible to explain the insufficient diagnostic information content of pulsed oscillometry. To increase the sensitivity and specificity of pulsed oscillometry, it is necessary not to limit the determination of acoustic indicators only at frequencies of 5 and 20 Hz, but to determine them in an extended frequency range with a more detailed step.

Intra- and inter-speaker variation in eight Russian fricativesa).

Acoustic variation is central to the study of speaker characterization. In this respect, specific phonemic classes such as vowels have been particularly studied, compared to fricatives. Fricatives exhibit important aperiodic energy, which can extend over a high-frequency range beyond that conventionally considered in phonetic analyses, often limited up to 12 kHz. We adopt here an extended frequency range up to 20.05 kHz to study a corpus of 15 812 fricatives produced by 59 speakers in Russian, a language offering a rich inventory of fricatives. We extracted two sets of parameters: the first is composed of 11 parameters derived from the frequency spectrum and duration (acoustic set) while the second is composed of 13 mel frequency cepstral coefficients (MFCCs). As a first step, we implemented machine learning methods to evaluate the potential of each set to predict gender and speaker identity. We show that gender can be predicted with a good performance by the acoustic set and even more so by MFCCs (accuracy of 0.72 and 0.88, respectively). MFCCs also predict individuals to some extent (accuracy = 0.64) unlike the acoustic set. In a second step, we provide a detailed analysis of the observed intra- and inter-speaker acoustic variation.

Features of vestibular function in patients with sensorineural deafness of vascular origin

Objective: to study the features of vestibular dysfunction in patients with sensorineural hearing loss of vascular origin, depending on the degree of discirculation in the main vessels of the head. Metods. We examined 60 patients with various degrees of sensorineural hearing loss with circulatory disorders in the vertebrobasilar system (VBS), including 36 (60%) women and 24 (40%) men. The average age of the surveyed was 49.9±1.89 years. All patients underwent audiometry in an extended frequency range up to 20 kHz, the study of acoustic stem evoked potentials, acoustic reflexometry. A caloric test was used to study experimental vestibular reactions, and the results were recorded using computerized electronystagmography. Results. According to the otoneurological examination, the patients were divided into 3 subgroups. Peripheral cochleovestibular syndrome (PCVS) was diagnosed in 14 (23%) patients, central cochleovestibular syndrome (CCVS) in 19 (32%), and combined cochleovestibular syndrome (CVS) was diagnosed in 27 (45%) patients. In the analysis of complaints presented by patients with SHD of vascular origin, the combined complaints of hearing deafness, tinnitus and neurological symptoms (headaches, amnesia, paresthesia, fatigue, etc.), as well as dizziness and neurological symptoms, significantly prevailed compared with individual complaints of hearing loss or dizziness (p &lt; 0.05). An analysis of the asymmetry of the pathological process on the right or left side did not reveal significant differences, however, the proportion of patients with bilateral lesions in the subgroup with CCVS was significantly higher. If vestibular nystagmus is an unconditioned stem reflex, then optokinetic nystagmus is a product of the activity of the cerebral cortex and occurs with the active participation of the patient himself in the process of research. Conclusion. The obtained data were compared with the structural changes and hemodynamic parameters in the blood of vertebral arteries (VA) and internal carotid arteries (ICA), as well as magnetic resonance imaging of the brain (MRI).