[Surgical tactic of cochlear implantation in patients with intraoperative CSF leakage]. / Khirurgicheskaya taktika pri kokhlearnoi implantatsii u patsientov s intraoperatsionnoi likvoreei.

Cochlear implantation (CI) is currently the recognized and most promising method of rehabilitation of patients suffering from profound hearing loss and deafness. During the surgical stage of CI, one of the most unpleasant intraoperative features is CSF leakage from the cochlea opening. Most often it occurs in patients with malformations of the inner ear, with temporal bone fractures and with cochlear otosclerosis. The difficulty of choosing the tactics of surgical intervention in these patients is caused by the large variability of the anatomical structures of the inner ear. In the period from 2017 to 2021, 1954 patients underwent CI, of which 83 were patients with cochlea malformations (65 intraoperative CSF leakages), 14 with the temporal bones fractures (2 intraoperative CSF leakage), 12 with cochlear otosclerosis (1 CSF leakage), while 3 spontaneous intraoperative CSF leakages were noted in patients with normal cochlea anatomy and hyperpnumotized temporal bone pyramid and enlarged vestibular aqueduct. The highest risk of intraoperative CSF leakage was observed in patients with inner ear malformations (common cavity - 10, incomplete partition type III - 15) and anomalies of the internal auditory canal - 5 (dilated IAC - more than 8.5 mm in diameter). Moderate risk of intraoperative CSF leakage was typical for patients with incomplete partition type I (15 patients) and type II (25 patients).

[Prospects for cochlear implantation in patients with auditory nerve dysplasia]. / Perspektivy kokhlearnoi implantatsii u patsientov s displaziei slukhovogo nerva.

Auditory nerve dysplasia (AND) can encompass various conditions of the auditory nerve (AN), ranging from true aplasia to hypoplasia. The purpose of this review is to discuss the prospect of cochlear implantation (CI) and subsequent auditory speech rehabilitation for AN abnormality. Studies of different authors when working with this category of children, possible results and methods of diagnostics of the AN condition are presented.

[The influence of hearing and vestibular impairments on cognitive function in elderly people.]

Cognitive function is a complex brain function that is important in the cognition of the reality and connecting with it. It has a complicated reflex basis, arises from external factors exposure, improves by growing up and learning till its maximum and declines in the elderly age. For several years it was believed that cognitive function drop is connected with ageing processes of the whole organism. However, the results of the latest studies show that it can be affected by many factors. Two of the most influencing factors are hearing and vestibular efficiency. Moreover, hearing and vestibular normalization can even improve the cognitive function. Unfortunately, studies, that describe the role of hearing and vestibular function in the cognitive sphere, are extremely rare. That is why further research is very important, especially in the rehabilitation tactics. For elderly patients with severe-to-profound hearing loss cochlear implantation is the optimal rehabilitation method. However, ear surgery can lead to such complication as vestibular dysfunction. That is why preoperative diagnostics and postoperative care are very important for preventing cognitive impairments.

[The significance of microanatomy of the round window in terms of cochlear implantation]. / Znachenie mikroanatomii okna ulitki dlya provedeniya kokhlearnoi implantatsii.

Sensoneural hearing loss is a polyetiological disease, which is often a secondary reflection of systemic pathology and is associated with damage of the cochlea and auditory nerve receptors. An important point in the surgical stage of cochlear implantation is the introduction of an implant active electrode into the cochleostomy spiral channel through the cochleostoma or round window. However, the issue of intra-cochlear structures surgical trauma in such surgical intervention seems to be very important, as it may reduce the success of subsequent rehabilitation. Therefore, the study of the anatomy of the round window and adjuscent areas was the objective of this work.

Evidence for the formation of two types of oxygen interstitials in neutron-irradiated α-Al2O3 single crystals.

Due to unique optical/mechanical properties and significant resistance to harsh radiation environments, corundum (α-Al2O3) is considered as a promising candidate material for windows and diagnostics in forthcoming fusion reactors. However, its properties are affected by radiation-induced (predominantly, by fast neutrons) structural defects. In this paper, we analyze thermal stability and recombination kinetics of primary Frenkel defects in anion sublattice - the F-type electronic centers and complementary oxygen interstitials in fast-neutron-irradiated corundum single crystals. Combining precisely measured thermal annealing kinetics for four types of primary radiation defects (neutral and charged Frenkel pairs) and the advanced model of chemical reactions, we have demonstrated for the first time a co-existence of the two types of interstitial defects - neutral O atoms and negatively charged O- ions (with attributed optical absorption bands peaked at energies of 6.5 eV and 5.6 eV, respectively). From detailed analysis of interrelated kinetics of four oxygen-related defects, we extracted their diffusion parameters (interstitials serve as mobile recombination partners) required for the future prediction of secondary defect-induced reactions and, eventually, material radiation tolerance.

Distinctive features of diffusion-controlled radiation defect recombination in stoichiometric magnesium aluminate spinel single crystals and transparent polycrystalline ceramics.

MgAl2O4 spinel is important optical material for harsh radiation environment and other important applications. The kinetics of thermal annealing of the basic electron (F, F+) and hole (V) centers in stoichiometric MgAl2O4 spinel irradiated by fast neutrons and protons is analyzed in terms of diffusion-controlled bimolecular reactions. Properties of MgAl2O4 single crystals and optical polycrystalline ceramics are compared. It is demonstrated that both transparent ceramics and single crystals, as well as different types of irradiation show qualitatively similar kinetics, but the effective migration energy Ea and pre-exponent D0 are strongly correlated. Such correlation is discussed in terms of the so-called Meyer-Neldel rule known in chemical kinetics of condensed matter. The results for the irradiated spinel are compared with those for sapphire, MgO and other radiation-resistant materials.

[Influence of hearing decline on cognitive function in elderly and senier age patients and its assessment after cochlear implantation (literature review).]

The study of the effect of cochlear implantation on cognitive function is an urgent problem, since the world is increasing the population of elderly and senile people who, as a rule, have certain hearing impairments. Age-related hearing loss is one of the most common health problems associated with aging, affecting two-thirds of people over the age of 70. However, few adults are tested for hearing loss, and even fewer are being treated. It is known that hearing loss - the most common sensory deficit-forms the prerequisites for narrowing the range of cognitive functions in the elderly and can serve as a factor accelerating the progression of cognitive changes. We analyzed the available research on the effects of hearing loss and cochlear implantation on cognitive function. It was revealed that for the most part, they had a small sample, the results were not subjected to the necessary statistical analysis, and the tests used were not adapted for hearing impaired people. After analyzing different tests for assessing cognitive function, HI-MoCA and RBANS-H tests were selected, which are adapted for hearing impaired people, which will allow to reliably assess cognitive function in the pre- and postoperative period, as well as to trace the effect of cochlear implantation on cognitive function in postoperative period.

[Round window niche area anatomy in terms of cochlear implantation]. / Anatomiia oblasti nishi okna ulitki primenitel'no k khirurgicheskomu étapu kokhlearnoi implantatsii.

Cochlear implantation is the most effective method of rehabilitation of patients with a high degree of hearing loss and deafness. This is a complex, multi-stage way of rehabilitation that includes selection of candidates for surgical intervention, a surgical stage and postoperative long-term auditory rehabilitation. In carrying out the surgical stage of cochlear implantation the round window niche area is of great interest, since the variability of its anatomical features affects the access to scala tympani. The article presents the data obtained from study of the round window niche area anatomy on cadaveric temporal bones. Variations of structures important for cochlear implantation have been determined.

[Topographic anatomy of the hook region and its significance for the choice of the surgical technique for the cochlear implantation]. / Topograficheskaia anatomiia oblasti 'rybolovnogo kriuchka' i ee znachenie pri vybore khirurgicheskoi tekhniki kokhlearnoi implantatsii.

The mode of the introduction of the active electrode of a cochlear implant into the cochlea remains a key issue as far as cochlear implantation is concerned. Especially much attention has recently been given to the relationship between the anatomical features of the basal region of the cochlea (the so-called 'fish hook') and the possibility to approach it. We have undertaken the attempt to optimize the approach to the tympanic canal (scala tympanica) of the cochlea with a view to reducing to a minimum the risk of an injury to the cochlear structures in the course of cochlear implantation. A total of 35 cadaveric temporal bones were examined to measure the fine structures of the hook region and evaluate the risk of their damages associated with various approaches to the tympanic canal.

[The use of thresholds of electrically evoked short-latent auditory potentials for the adjustment of the speech processors in the patients undergoing cochlear implantation].

The objective of the present study was to determine the thresholds of electrically evoked short-latent auditory potentials by the mathematical method and to elucidate the relationship between these parameters and the subjective maximally comfortable levels in the patients undergoing cochlear implantation. The electrically evoked short-latent auditory potentials were recorded in two groups of patients with different stimulation frequency (17 and 43 Hz). The use of the mathematical method of linear regression of the amplitude (peak V) growth function for determining the thresholds of electrically evoked short-latent auditory potentials has a number of advantages over visual detection of the threshold level. To increase the reliability of the data obtained, low stimulation frequencies need to be used when recording electrically evoked short-latent auditory potentials (17 Hz). The calculated thresholds of electrically evoked short-latent auditory potentials can be used to estimate the subjective maximally comfortable levels for the adjustment of the speech processors when it is impossible to register electrically induced stapedial reflexes and electrically induced total action potentials of the auditory nerve in the patients having cochlear implants.

Static and dynamic screening effects in the electrostatic self-assembly of nano-particles.

In the description of charge screening in the electrostatic self-assembly of nanoparticles (molecules) embedded into a polar solvent, the static screening effects (a contribution associated with the rapid spatial redistribution of small and highly mobile ions of a solvent) are traditionally treated phenomenologically, using the Yukawa short-range potential for describing the interaction between these particles. However, this model has a limited range of applicability being valid only for infinitely diluted systems and high salt concentrations. During a slow self-assembling process with nanoparticle formation, very dense structural elements (aggregates) are formed, in which the distances between the nanoparticles could become comparable to the Debye radius in the Yukawa potential. For such structural elements dynamic screening effects (the contribution of nanoparticles themselves to the screening potential) become important. In this paper, using a novel integrated approach (nonlinear integro-differential kinetic equations for the correlation functions of particles), we have obtained the self-consistent solution in the 3d case and compared roles of both static (equilibrium) and dynamic (nonequilibrium) charge screening effects in different situations. This paper is a continuation of our recent study [Phys. Chem. Chem. Phys., 2014, 16, 13974], where the polar solvent effects were now taken into account.

Theory of non-equilibrium critical phenomena in three-dimensional condensed systems of charged mobile nanoparticles.

A study of 3d electrostatic self-assembly (SA) in systems of charged nanoparticles (NPs) is one of the most difficult theoretical problems. In particular, the limiting case of negligible or very low polar media (e.g. salt) concentration, where the long-range NP interactions cannot be reduced to commonly used effective short-range (Yukawa) potentials, remains unstudied. Moreover, the present study has demonstrated that unlike the Debye-Hückel theory, a complete screening of the charges in SA kinetics (dynamic SA) is not always possible. Generally speaking, one has to take into account implicitly how each NP interacts with all other NPs (the true long-range interactions). Traditional theoretical methods allow us to monitor such electrostatic 3d system kinetics only for very short times, which is far from sufficient for understanding the dynamic SA. In this paper, combining an integrated analytical approach (the non-linear integro-differential kinetic equation for correlation functions) and reverse Monte Carlo in the 3d case, we have obtained a self-consistent solution of this challenging problem. We demonstrate, in particular, the existence of critical points and critical phenomena in the non-equilibrium kinetics in a 3d system of oppositely charged mobile NPs.

Towards a consensus on a hearing preservation classification system.

CONCLUSION: The comprehensive Hearing Preservation classification system presented in this paper is suitable for use for all cochlear implant users with measurable pre-operative residual hearing. If adopted as a universal reporting standard, as it was designed to be, it should prove highly beneficial by enabling future studies to quickly and easily compare the results of previous studies and meta-analyze their data. OBJECTIVES: To develop a comprehensive Hearing Preservation classification system suitable for use for all cochlear implant users with measurable pre-operative residual hearing. METHODS: The HEARRING group discussed and reviewed a number of different propositions of a HP classification systems and reviewed critical appraisals to develop a qualitative system in accordance with the prerequisites. RESULTS: The Hearing Preservation Classification System proposed herein fulfills the following necessary criteria: 1) classification is independent from users' initial hearing, 2) it is appropriate for all cochlear implant users with measurable pre-operative residual hearing, 3) it covers the whole range of pure tone average from 0 to 120 dB; 4) it is easy to use and easy to understand.

[The objective method for recording stapedial reflex during surgery for cochlear implantation].

The purpose of the present study was to develop a method for the objective registration of the stapedial reflex at the contralateral ear during cochlear implantation surgery on the affected one. The excessive pressure in the middle ear (up to 500 daPa) was compensated by the administration of an additional air volume (1 liter) into the AA220 impedance meter pneumatic circuit. A syringe was used to measure variations of pressure in the new pneumatic circuit. Eight of the 12 patients demonstrated coincident visual and objective reflex thresholds. In the remaining 4 patients, the visually apparent stapedial reflex thresholds proved higher than those obtained objectively by the standard procedure of impedancemetry. It is concluded that the objective registration of the stapedial reflex excludes the effect of subjective factors interfering with its estimation and provides the possibility for comparative intra- and postoperative studies using one and the same instrument.

Atomistic theory of mesoscopic pattern formation induced by bimolecular surface reactions between oppositely charged molecules.

The kinetics of mesoscopic pattern formation is studied for a reversible A+B⇌0 reaction between mobile oppositely charged molecules at the interface. Using formalism of the joint correlation functions, non-equilibrium charge screening and reverse Monte Carlo methods, it is shown that labyrinth-like percolation structure induced by (even moderate-rate) reaction is principally non-steady-state one and is associated with permanently growing segregation of dissimilar reactants and aggregation of similar reactants into mesoscopic size domains. A role of short-range and long-range reactant interactions in pattern formation is discussed.

Pattern formation kinetics for charged molecules on surfaces: microscopic correlation function analysis.

The kinetics of pattern formation and phase separation in a system of two types of oppositely charged molecules with competing short- and long-range interactions on surfaces/interfaces is studied combining three methods: a microscopic formalism of the joint correlation functions, reverse Monte Carlo, and nonequilibrium charge-screening factors. The molecular ordering occurs on the background of the Ostwald ripening and thus is strongly nonequilibrium. We have demonstrated how initial random distribution of molecules is changed for loose similar-molecule aggregates, with further reorganization into dense macroscopic domains of oppositely charged molecules. Pattern formation process is characterized by the correlation length which monotonically increases in time.

[Organization of remote long-term support of the patients with cochlear implants in distant regions].

The concept of remote long-term support of the patients with cochlear implants is suggested to cope with the problem of the increasingly growing number of patients with cochlear pathology. The authors deem it necessary to provide intraoperative support and postoperative follow-up technologies for the patients living far from the cochlear implantation centres. A scheme for the remote selection of patients and their intraoperative monitoring is proposed with the use of implant telemetry, electrical stapedial reflex (eSRT) testing, auditory response telemetry (ART), and surgical on-line counseling. Remote follow-up and rehabilitation should include cochlear implant tuning, speech therapy, and on-line workshops for the patients and/or specialists. The choice and the use of software and hardware for this purpose are discussed. The concept of remote long-term support turned out to be an efficacious, reliable, time-saving, and cost-effective tool for providing high-tech medical aid to patients with ENT diseases in the Krasnoyarsk kray (territory).

The non-equilibrium charge screening effects in diffusion-driven systems with pattern formation.

The effects of non-equilibrium charge screening in mixtures of oppositely charged interacting molecules on surfaces are analyzed in a closed system. The dynamics of charge screening and the strong deviation from the standard Debye-Hückel theory are demonstrated via a new formalism based on computing radial distribution functions suited for analyzing both short-range and long-range spacial ordering effects. At long distances the inhomogeneous molecular distribution is limited by diffusion, whereas at short distances (of the order of several coordination spheres) by a balance of short-range (Lennard-Jones) and long-range (Coulomb) interactions. The non-equilibrium charge screening effects in transient pattern formation are further quantified. It is demonstrated that the use of screened potentials, in the spirit of the Debye-Hückel theory, leads to qualitatively incorrect results.

Microscopic approach to the kinetics of pattern formation of charged molecules on surfaces.

A microscopic formalism based on computing many-particle densities is applied to the analysis of the diffusion-controlled kinetics of pattern formation in oppositely charged molecules on surfaces or adsorbed at interfaces with competing long-range Coulomb and short-range Lennard-Jones interactions. Particular attention is paid to the proper molecular treatment of energetic interactions driving pattern formation in inhomogeneous systems. The reverse Monte Carlo method is used to visualize the spatial molecular distribution based on the calculated radial distribution functions (joint correlation functions). We show the formation of charge domains for certain combinations of temperature and dynamical interaction parameters. The charge segregation evolves into quasicrystalline clusters of charges, due to the competing long- and short-range interactions. The clusters initially co-exist with a gas phase of charges that eventually add to the clusters, generating "fingers" or line of charges of the same sign, very different than the nanopatterns expected by molecular dynamics in systems with competing interactions in two dimensions, such as strain or dipolar versus van der Waals interactions.