[Clinical protocol: audiological assessment of infants in Russian Federation. Part II]. / Protokol audiologicheskogo obsledovaniya detei pervogo goda zhizni v Rossiiskoi Federatsii. Chast' II.

This is the second part of the previously published clinical protocol of audiological assessment in infants. The goal of the protocol is unification approaches to audiological diagnosis of the infants. The following sections were included in the second part of the protocol: behavioral testing in infants, testing sequence, duration of the examination and necessity in follow-up, hearing assessment in special cases (premature children, children with congenital infections, after meningitis, with external ear abnormalities, single-sided deafness, with hydrocephalus and shunts, with auditory neuropathy spectrum disorder, with mild hearing loss and otitis media with effusion), medical report.

[Clinical protocol: audiological assessment of infants in Russian Federation. Part I]. / Protokol audiologicheskogo obsledovaniya detei pervogo goda zhizni v Rossiiskoi Federatsii. Chast' I.

The clinical protocol of audiological assessment in infants was prepared by the workgroup of Russian pediatric audiologists from different regions. The goal of the protocol is unification approaches to audiological diagnosis of the infants. The protocol has been developed according the evidence based medicine principles, by reviewing current scientific publications on the topic and taking into account the order of providing medical services and other clinical practice guidelines. When direct evidence was not available, both indirect evidence and consensus practice were considered in making recommendations. This guideline is not intended to serve as a standard to dictate precisely how the child should be diagnosed. This guideline is meant to provide the evidence base from which the clinician can make individualized decisions for each patient. The first part of the protocol covers following sections: equipment, staff requirements, timing of the diagnostics, case history and risk factors, preparing the child for the appointment, sedation and general anesthesia, otoscopy, tympanometry and acoustic reflex, otoacoustic emissions, skin preparing, electrode montage, choosing the stimulators, auditory brainstem responses on broadband and narrow-band stimuli, on bone conducted stimuli, auditory steady-state responses, masking, combined correction factors.

[New criteria for professional selection and professional suitability by hearing to work in conditions of exposure to industrial hazards]. / Novye kriterii profotbora i profprigodnosti po slukhu dlya raboty v usloviyakh vozdeistviya proizvodstvennykh vrednostei.

New regulations of professional selection and professional suitability for the state of auditory function for persons entering for the first time and already working under the influence of harmful and (or) hazardous production factors are discussed.

[Electrically evoked ABR through cochlear implant in children with auditory neuropathy spectrum disorder]. / Registratsiya elektricheski vyzvannykh korotkolatentnykh slukhovykh potentsialov u detei s zabolevaniem spektra auditornykh neiropatii.

OBJECTIVE: To estimate the applicability of electrically evoked auditory brainstem response (eABR) registration for the estimation of neural integrity after cochlear implantation (CI) in children with auditory neuropathy spectrum disorder (ANSD) and to compare the eABR data with patient's hearing performance. MATERIAL AND METHODS: 4 children, Nucleus (Cochlear) CI users, with ANSD were enrolled in the study. Hearing performance in these children ranged from successful to unsatisfied. eABR were recorded via Eclipse EP25 (Interacoustics). Electrical bipolar stimulation was achieved with Custom Sound EP software (Cochlear). RESULTS: EABR were registered with the use of different stimulation parameters (pulse width, stimulated electrodes) in 3 patients with satisfactory results of rehabilitation. eABR thresholds corresponded to maximum comfortable levels of patients stimulation MAP. eABR were absent in the patient with poor hearing performance. CONCLUSIONS: EABR measurements in children with ANSD demonstrated restoration of neuronal conduction in the auditory pathway up to the brainstem after cochlear implantation in 3 patients. eABR results were well correlated with hearing performance. Thereby, the study of eABR applicability for clinical practice will be expanded.

Early audiological phenotype in patients with mutations in the USH2A gene.

INTRODUCTION: Nowadays, due to universal newborn hearing screening (UNHS) the number of children with mild-to-moderate hearing loss diagnosed in the first year of life has increased significantly. Aside from that, identification of the genetic cause improves the genetic counselling of the families and allows to reveal possible comorbidities which may need a special approach. OBJECTIVE: To present the characteristics of the early audiologic phenotype in hearing impaired patients with biallelic mutations in the USH2A gene based on systematic analysis of the audiological data. PATIENTS AND METHODS: 13 patients with mutations in the USH2A gene underwent audiological examination. Most of them were found among a large group of infants with bilateral nonsyndromic sensorineural hearing loss (SNHL) examined under 12 months. RESULTS: Eight out of eleven children failed UNHS and were initially diagnosed as having bilateral nonsyndromic SNHL. Seven children underwent an audiological assessment before the age of 9 months. The earliest audiological examination was carried out at 1 and 3 months. The children with pathogenic variants in the USH2A gene in our examined group were identified in the first year of life via UNHS. The hearing threshold levels (HTL) for the USH2A group are compactly distributed between 51.25 dB and 66.25 dB, quartiles are 54 dB and 63.4 dB, with a median of 60 dB. The audiological profile of patients with biallelic USH2A mutations differs from audiograms of patients who had STRC-related hearing loss. We have not found any significant elevation in hearing thresholds in the first decade of life. We also estimated the prevalence of the USH2A and STRC mutations among GJB2-negative infants with bilateral nonsyndromic SNHL examined under 12 months, and it was 7.5% and 16.1%, respectively. CONCLUSION: According to our results, the early hearing phenotype in pediatric patients with biallelic mutations in the USH2A- gene is characterized by nonsyndromic mild-to-moderate SNHL in the first decade of life. Our results indicate that the presence of mutations in the USH2A or STRC genes can be expected in a child with congenital mild-to-moderate nonsyndromic SNHL. This information is of practical importance for parents, as they have to know the prognosis of hearing loss for their child from the very beginning. Post-screening follow-up should include adequate clinical, genetic, and social support for children and their parents.

[Evaluation of the cochlear implantation users rehabilitation results using psychoacoustic methods]. / Otsenka rezul'tatov reabilitatsii pol'zovatelei kokhlearnykh implantatov s primeneniem psikhoakusticheskikh metodov issledovaniya.

Currently, the number of patients with bilateral sensorineural deafness treated with cochlear implantation (CI) is increasing in the Russian Federation. In this regard, methods of assessing the auditory rehabilitation of this category of patients become more relevant. OBJECTIVE: To investigate the correlation of the speech intelligibility in quiet with frequency resolving power (FRP) of hearing using a ripple-spectrum phase reversion test (RSPRT) in CI users. MATERIAL AND METHODS: The study includes 30 CI users, three of them after bilateral CI, aged from 13 to 63 years with CI usage experience from 1 year to 16 years. 19 patients used CI systems manufactured by Cochlear Ltd. (Australia), 11 patients used CI systems manufactured by Advanced Bionics (Switzerland). All subjects underwent a number of studies including pure tone audiometry (TPA), speech audiometry in quiet using a multi-syllable speech material on a two-channel clinical audiometer AC-40 (Interacoustics A/S, Denmark); PC with recorded phonetic material from which the signal was reproduced, acoustic speaker SP90 (Interacoustics A/S, Denmark), for FRP estimation - RSPRT test in a free sound field, which was installed on the PC and also reproduced through SP 90 speakers (Interacoustics A/S, Denmark) were used. RESULTS: According to TPA results in a free sound field, the sound perception thresholds in all subjects corresponded to the mild degree sensorineural hearing loss. The sound perception threshold in the free sound field in the range from 500 Hz to 4 kHz was within the range of 25-30 dB nHL. The percentage of speech intelligibility in quiet in the free sound field ranged from 5 to 100%. During the FRP study of patients using RSPRT test, the following results were obtained: the average value of RSPRT test results at the frequency of 1 kHz was 1.94 RPO; for 2 kHz - 2.3 RPO; for 4 kHz - 2.2. The significant correlation between the speech intelligibility in quiet and frequency resolution of hearing was obtained at 1 and 4 kHz. The highest correlation coefficient was detected at 1 kHz - r=0.57 (p=0.0005), while at 4 kHz it was lower - r=0.46 (p=0.009), and at 2 kHz - at the boundary of the significance: r=0.34 (p=0.051). CONCLUSIONS: As a result of the study, it was found that there is a correlation between speech intelligibility in quiet and FRP of hearing, which makes it possible to recommend the use of RSPRT in assessing the auditory rehabilitation of patients after CI.

[Ethical analysis of work environment in audiology]. / Analiz eticheskikh aspektov trudovoi deyatel'nosti vrachei-surdologov-otorinolaringologov i vrachei-otorinolaringologov.

The issues of medical ethics concern not only the doctor-patient relationship, but also the ethical aspects of the organization of the labor activity of medical specialists. Identifying and resolving ethical dilemmas can serve as the basis for preventing occupational stress and burnout and improving the effectiveness of medical care in the field of audiology. OBJECTIVE: Ethical analysis of work environment in audiology. MATERIAL AND METHODS: A 14-question questionnaire developed on the basis of demand-control and effort-reward models, an online survey was conducted using the Google Forms service among 111 specialists (43 audiologists, 13 otorhinolaryngologists, and 55 doctors combining work in both specialties).Results and discussion. The differences were revealed on the scales Effort and Reward depending on the specialty and clinic (public or private). The greatest effort was found among doctors combining both specialties, the least - among doctors of private clinics. 58% of the respondents consider the wages to be inadequate to the expended efforts. At the same time, a high respect level among patients, management and colleagues helps to compensate for the identified efforts. CONCLUSION: The analysis made it possible to identify ethical dilemmas in the work of audiologists for effective planning of specialty development.

[Postoperative dynamics of electrode impedance changes in children with cochlear implants]. / Posleoperatsionnaya dinamika soprotivleniya elektrodov u detei s kokhlearnymi implantami.

To determine the electrode impedance dynamics changes in the postoperative period after cochlear implantation as well as the time of their stabilization. MATERIAL AND METHODS: 75 patients with a bilateral sensorineural deafness aged from 1 to 4 years (average age - 1.5 years) were included in the study. 50 patients were implanted with Nucleus cochlear implants (Cochlear - Australia) and other 25 patients - with Advanced Bionics implants (Switzerland). RESULTS: The impedance dynamics analysis in two groups of patients implanted with «Cochlear¼ and «Advanced Bionics¼ cochlear implants demonstrated that statistically significant decrease in impedance (p<0.05) was observed after the beginning of electrical stimulation and the reduction of postoperative inflammatory process in the inner ear. The stabilization of the impedance levels in both groups of patients was obtained in 3-6 months after the switch-on of speech processor.

Clinical features of hearing loss caused by STRC gene deletions/mutations in Russian population.

Congenital sensorineural hearing loss is related to mutations in numerous genes encoding the structures of the inner ear in majority of the cases. Mutations in GJB2 gene are the most frequently identified causes of congenital nonsyndromal hearing loss. GJB2 gene testing became a routine clinical tool. For GJB2-negative patients new genetic approaches including methods based on new generation sequencing give a chance to identify mutations in other genes. The frequent reason of mild-to-moderate hearing loss such as the deletions/mutations of the gene STRC encoding stereocilin protein were recognized (OMIM: 606440). OBJECTIVES: To evaluate the audiological features in hearing impaired patients with deletions and point mutations in the STRC gene. PATIENTS AND METHODS: The group of 28 patients from 21 unrelated families with pathological mutations in the STRC gene underwent audiological examination. The description and analysis of the results of full audiological examination was provided. RESULTS: All patients initially had bilateral nonsyndromal sensorineural hearing loss. Among 11 homozygotes of large deletion harboring STRC to CATSPER2 genes were 7 male individuals indicating the presence of male infertility syndrome. In general, 7 children failed audiological screening and 4 children underwent audiological assessment in the age of 3 and 6 months. The most frequently hearing thresholds were registered between 35 and 55 dB that corresponds to mild-to-moderate hearing impairment. The average age of diagnostics was 7.9 years (ranged from 3 months to 45 years). In the majority of patients the audiological profiles were flat or descending with elevation of thresholds at middle and high frequencies and relatively preserved thresholds at low frequencies. Hearing thresholds are symmetric and stable with age. CONCLUSION: STRC-linked hearing loss is congenital, of mild and moderate severity. Special clinical and genetic approach for children who failed newborn hearing screening with mild-to-moderate hearing loss is necessary.

[Hearing loss due to mutations or lack of the gene coding protein stereocillin]. / Narushenie slukha pri mutatsiyakh ili otsutstvii gena, kodiruyushchego belok stereotsilin.

OBJECTIVE: The description of a clinical picture and audiological features at the hearing loss caused by changes of a STRC gene, coding protein stereocillin (MIM: 606440). Mutations in the numerous genes responsible for the inner ear proteins are the reason for congenital sensorineural hearing loss. The main cause of congenital bilateral sensorineural hearing loss in the Russian Federation are mutations in GJB2 gene it reaches up 68% of cases identified in infancy. GJB2 gene tests already became routine around the world. Possibilities of new methods based on sequencing of new generation (NGS, next generation sequencing) allow to conduct a research of more rare genes connected with a hearing impairment. The most often among GJB2 negative patients reveal mutations and deletion of a gene of STRC. PATIENTS AND METHODS: Full audiological examination of 5 children and one adult with a hearing loss from 2 unrelated families is provided. Mutations in STRC gene were identified. All children are examined aged before 8 years, and 3 children failed universal audiological screening in maternity hospital, to two children screening was not carried out as they were born till 2009. RESULTS: The children with the sensorineural hearing loss connected with mutations and deletion of STRC gene failed hearing screening in maternity hospital because of the OAE is not registered, what indicates the congenital nature of a hearing loss. Recently it could not be noticed earlier because of slight increase of hearing thresholds and was regarded only as the early onset. Our data emphasize that the of thresholds from 35 to 60 dB in frequencies 0,5-4 kHz is common for mutations/deletions of STRC gene. CONCLUSION: The development of molecular genetics methods confirms the hereditary causes of GJB2-negative patients and expands indications for family counseling. Special approach for child with hearing loss so early revealed is necessary and the consultation of parents frightened of screening results is very important.

[OTOF-related auditory neuropathy spectrum disorder]. / Zabolevanie spektra auditornykh neiropatii, obuslovlennoe mutatsiyami v gene otoferlina (OTOF).

Otoferlin (OTOF) gene mutations are the most common cause of hereditary ANSD according to investigations in several countries. THE AIM: Of this study was to estimate the prevalence of OTOF mutations in Russian children with ANSD and evaluate audiological and clinical features of OTOF-related ANSD. PATIENTS AND METHODS: 28 children with bilateral ANSDwere enrolled in the investigation. Two step genetic testing was performed: first step - GJB2 gene testing to exclude GJB2-related hearing loss; second step - NGS-based sequencing to explore another 35 hearing loss genes (including OTOF). RESULTS: OTOF mutations, including 6 new variants, were found in 5 children with ANSD (18%). All 5 children had no risk factors for hearing loss and passed hearing screening. OAE and cochlear microphonics were present till the last testing at the age of 4-5 years. ABR were not detectable. The ASSR were measurable bilaterally at all frequencies in all cases, but they did not correlate with behavioral thresholds that revealed severe hearing loss. Hearing thresholds were stable during follow up period. 3 children underwent cochlear implantation. After cochlear implantation auditory nerve action potentials to electric stimulation were detected within normal range. CONCLUSION: Genetic testing of children with ANSD and first of all OTOF testing enables to reveal hearing loss etiology and provide the optimal rehabilitation approach, including cochlear implantation, as early as possible.

[Application of the matrix sentence test Russian version in children]. / Primenenie russkoiazychnoi versii matriksnogo frazovogo testa u detei.

The Russian version of the matrix sentence test (RUMatrix test) has been shown to be suitable for accurate assessment of speech intelligibility in adults. AIM: To approve the RUMatrix for measurements in children and to evaluate its simplified version (Simplified RUMatrix). MATERIAL AND METHODS: 20 normal-hearing adults and 81 normal-hearing children aged from 5 to 10 years were involved into the study. Both versions of the test were developed by the University of Oldenburg, Germany. The tests contain syntactically homogeneous, semantically unpredictable sentences/phrases presented under the background noise. Each test list is composed of 20 sentences of 5 words for RUMatrix and of 14 speech phrases of 3 words for Simplified RUMatrix. RESULTS: A limitation in the use of the RUMatrix test in children under 10 years of age has been revealed. Evaluation of Simplified RUMatrix test in adults confirmed the perceptual homogeneity of the test list. The results of the RUMatrix test and the Simplified RUMatrix test in children were lower than in adults; they were improving with age and reach adult values by 10 years. One training track of Simplified RUMatrix test should be carried out before the assessment. CONCLUSION: The RUMatrix can be used for children of 10 years and older. The normative data of Simplified RUMatrix both for adults and children of the different ages have been obtained.

[Threshold dynamics of the auditory nerve electrically evoked compound action potential in implanted children]. / Dinamika porogov elektricheski vyzvannogo potentsiala deistviya slukhovogo nerva u implantirovannykh detei.

OBJECTIVE: To study the dynamics of thresholds of the electrically evoked compound action potential of the auditory nerve (ECAP) during neural responce telemetry (NRT) intraoperatively, at the time of activation of the cochlear implantation system (CI) and after 3 and 6 months. MATERIAL AND METHODS: The study included 50 children aged 1 year to 4 years with bilateral sensorineural deafness, operated on by Nucleus CI512 Profile + CP900 CI systems («Cochlear¼, Australia). In all patients, the electrode array was fully inserted. The dynamics and thresholds of ECAP were recorded and assessed in dynamics: when performing NRT intraoperatively, when the CI system was activated, and after 3 and 6 months. To assess the thresholds, the 1st, 6th, 11th, 16th and 22nd electrodes of the multichannel electrode array were selected. RESULTS: The average threshold values and the NRT threshold profile determined intraoperatively and during measurements at different times after the activation of the CI system were significantly different (p<0.001), while the average postoperative results were characterized by relative stability. It was shown that the thresholds determined on the electrodes located in the middle of the electrode lattice are more stable than the thresholds determined on the apical and basal electrodes. In most patients, the NRT threshold values determined at the time of the activation of the CI system and after 3 and 6 months were significantly lower than the thresholds determined intraoperatively. The data obtained allow us to conclude that NRT is a stable and accurate technique that allows you to objectify the process of setting up an individual card for the stimulation of the speech processor at the rehabilitation stage after cochlear implantation.

[Key points of 'Noise-induced hearing loss' clinical guidelines]. / Osnovnye polozheniia klinicheskikh rekomendatsii 'Poteria slukha, vyzvannaia shumom'.

In this article we present the key points of 'Noise-induced hearing loss' clinical guidelines, which are included to the Clinical Guidelines Classifier of the Ministry of Health of Russia (2018). We give the definition of 'Noise-induced hearing loss', disclose the main causes and pathogenetic features of hearing impairment in employees who are affected by intensive noise at work. We state the main clinical and diagnostic criteria, treatment and rehabilitation principles; present the basics of primary and secondary prevention of hearing impairment in 'noise-hazardous' workers. We also disclose in detail the algorithm of expertise of hearing diseases connection with the profession on the stages of preliminary and final professional disease. Professional suitability issues are also discussed. Clinical guidelines contain a unified classification of noise-induced hearing loss severity complied with international approaches and medical and social expertise criteria.

[Auditory evoked potentials in children with auditory neuropathy spectrum disorder]. / Slukhovye vyzvannye potentsialy u detei s zabolevaniem spektra auditornykh neiropatii.

The objective of the present study was to estimate peculiarities of the auditory brainstem evoked potentials (ABR), auditory steady-state responses (ASSR) and cortical auditory evoked potentials (CAEP) in the children presenting with bilateral auditory neuropathy spectrum disorder (ANSD). The study included 100 patients with bilateral ANSD diagnosed based on the positive response of otoacoustic emissions (OAEs) and/or cochlear microphonic (CM) detection, while no synchronous neural activity was detected in the ABR test. Cochlear microphonic was the main clue for the ANSD diagnosing, because OAE was absent in both ears of 49 children. ABR testing revealed no response bilaterally in 72 cases (out of 100). In contrast to ABR, the ASSR thresholds were detectable at all the four main frequencies in both ears in 73 % of the cases (47 out of the 64 tested ones). Both ABR and ASSR in most cases were incomparable with the behavioral audiometric thresholds. 28 children underwent CAEP testing. In 7 cases out of 8 with mild hearing loss detectable CAEP were recorded. CAEP registration in l7 children making use of the hearing aids and in 3 children after cochlear implantation revealed, in the majority of the cases, the concordance between CAEP detectability with behavioral thresholds and rehabilitation outcomes with fairly good speech intelligibility. It is concluded that the ABR registration with CM evaluation is the most informative test for ANSD diagnosis. However, ABR as well as ASSR is useless for the estimation of the behavioral thresholds. The results of this study suggest that the presence or absence of CAEPs can provide some indication of the audibility of a speech sound in the children with ANSD; however this method requires further investigation.

[Evoked potentials in the rehabilitation of the patients after cochlear implantation]. / Vyzvannye potentsialy v reabilitatsii patsientov posle kokhlearnoi implantatsii.

The objective methods for the hearing examination of the patients after cochlear implantation provide an important tool for the speech processor fitting. The aim of the present study was to evaluate the possibilities and the informative value of the electrically evoked compound action potential (ECAP) and electrically evoked auditory brainstem response (EABR) combined recording technique. For this reason, the comparison of the ECAP and EABR thresholds with comfortable levels of stimulation, obtained on the basis of subjective response and psychophysical testing of the patients with good results after cochlear implantation was performed. 19 patients with the CI experience from 1 to 5 years were included in our study. The combined registration of ECAP and EABR can be used to evaluate the functional capacity of the central auditory pathways and for the fitting of the complicated patients, especially those in whom the registration proved impossible with the use of other objective techniques. The ECAP and EABR threshold values were well correlated with the individual stimulation map profiles in the patients with the CI experience of less than two years (p<0.05). The results obtained in the present study allow us to conclude that combined registration of ECAP and EABR could be used for the determination of stimulation comfort level parameters and individual stimulation map profiles, especially in combination with the minimum amount of psychoacoustic information received from the patient.

[The method for the simultaneous registration of several frequency-specific short latency auditory brain-stem responses]. / Metod odnovremennoi registratsii neskol'kikh chastotno-spetsifichnykh korotkolatentnykh slukhovykh vyzvannykh potentsialov.

The present article was designed to describe the newly proposed method for the simultaneous registration of several frequency-specific short latency auditory evoked potentials based on the use of the sequences of the maximum length. The mutual masking between he sequences of different frequency bands was investigated. The possibility for the simultaneous registration of five responses to the stimuli with the central frequency of 0.5, 1, 2, 4, and 8 kHz has ben demonstrated.

[Twenty years of clinical studies of GJB2-linked hearing loss in Russia]. / 20 let izucheniia klinicheskikh proiavlenii GJB2-obuslovlennoi tugoukhosti v Rossii.

The most common cause of congenital hereditary hearing loss was discovered 20 years ago in 1997 when GJB2 gene was revealed in the first locus of recessive hearing loss DFNB1. It encodes protein connexin 26, a structural component of the intercellular channels. Recessive mutations in this gene cause the congenital bilateral sensorineural hearing loss. For many years the aim of our work was to study the prevalence and clinical manifestations of hereditary hearing loss. Our research can be divided into three stages. In the beginning, we investigated the prevalence of GJB2 mutations in a healthy population and in the people suffering from hearing impairment. Further research was conducted in the field of clinical manifestations and evidence of the congenital character of GJB2-related hearing loss. Currently, we are working on the prevalence of mild and moderate hereditary hearing loss and the probability of its progression. Achievements in molecular genetics make it possible to establish the hereditary character of congenital hearing loss and to avoid repeated family cases. Primary prevention of hereditary hearing loss becomes real by raising the awareness of GJB2 mutations carriers.

[Epidemiology of hearing loss in children of the first year of life]. / Épidemiologiia narushenii slukha sredi detei 1-go goda zhizni.

The aim of this study was the investigation of the epidemiology of permanent hearing impairment in the children of first year of life in the Russian Federation after the implementation of the newborn universal hearing screening program. The prevalence of hearing loss in children in the first year of life was estimated at 2.5 per 1,000 based on the official statistical data and reports of hearing rehabilitation centres in 2016. A cohort of 405 children born in 2012 was examined at the age from 0 to 4 years of life. Among them 276 children were diagnosed with permanent congenital and prelingual hearing loss. 88% of the cases were bilateral, sensorineural hearing loss confirmed in 84% of the cases. The genetic cause of hearing loss was revealed in 58% of the patients assessed for the presence of GJB2 gene mutations. In preterm infants, the permanent hearing loss was detected in 70% of the cases. The comprehensive audiological assessment before 3 months of life was conducted only in 32% of the children; this finding is not consistent with the international newborn hearing screening recommendations. Only 70% of the cases of congenital and preverbal hearing loss were diagnosed during the first year of life.

[The electrically evoked potentials of the auditory cortex]. / Élektricheski vyzvannye potentsialy slukhovoi kory.

The problems concerning the registration of late latency auditory responses to electric stimulation in the patients wearing cochlear implants are considered. The renewed interest to this class of evoked potentials is due to unexplained differences in the results of cochlear implantation in the patients with the similar audiological data, etiology, age and the history of deafness as well as cochlear implant surgery in children of first years of life and the extended possibilities for speech processor programming. It is maintained that the advantages of this method include the possibility to objectively evaluate the ability of brain to detect and discriminate between different stimulus characteristics, such as loudness differences, temporal changes or speech tokens. This method is of great clinical significance for the electrophysiological monitoring of brain plasticity and documentation of the clinical effectiveness of different rehabilitation methods. Based on our own experimental and clinical results and the literature data, we consider the application of different electrically evoked late latency potentials for the monitoring of the auditory pathway maturation dynamics during the electric stimulation as well for the estimation of the effectiveness of cochlear implantation. It is concluded that the longer duration of deafness and later age at implantation result in immature morphology and delayed peak latencies and that patients with shorter latencies and higher amplitudes have better speech perception. The use of different classes of electrically evoked responses of auditory cortex could provide the objective control of the effectiveness of the rehabilitative measured in the children following cochlear implantation.