[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.

[Hearing loss due to mutations in the genes responsible for Usher syndrome]. / Narushenie slukha pri mutatsiyakh v genakh, otvetstvennykh za sindrom Ashera.

Usher syndrome is characterized by congenital bilateral sensorineural hearing loss and progressive retinitis pigmentosa, and has an autosomal recessive type of inheritance. The purpose of this work is to summarize the modern data of a clinical picture of Usher syndrome and analyse hearing impairment properties. The frequency of the syndrome among children suffering from hearing loss and deafness is from 3 to 10%. The prevalence of the syndrome in the world is estimated as 4.4 per 100.000 population. The complexity of the diagnosis of the syndrome lies in the significant clinical and genetic heterogeneity. Hearing and vision problems begin at different ages. Primary diagnosis begins with the clinical diagnosis of bilateral hearing loss and visual impairment manifests later. In this case the initial diagnosis of nonsyndromal hearing loss will not be definitive. Molecular genetic studies contribute to the early clinical diagnosis of the syndrome. Understanding the cause of the disease allows to conduct correct medical and genetic counseling and get closer to solving treatment problems.

[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 clinical definition and etiology of Pendred syndrome (a review of the literature and clinical observations)]. / Sindrom Pendreda (obzor literatury i klinicheskie nablyudeniya).

The aim of this work was a clinical study of the patients with mutations in the SLC26A4 gene and clinical diagnosis of the Pendred syndrome. The Pendred syndrome is a hereditary autosomal recessive disorder characterized by combined pathology of the inner ear and the thyroid gland. CT of the temporal bones demonstrates the Mondini-type structural anomaly in the inner ear and enlarged vestibular aqueduct. Examination of the thyroid gland reveals hypothyroidism and euthyroid goiter. A total of 20 unrelated children at the age from 2 to 16 years presenting with the hearing loss of different severity were available for the examination. High-resolution CT of the temporal bones demonstrated abnormal development of the inner ear including the Mondini-type structural anomaly and enlarged vestibular aqueduct. Five children with congenital hypothyroidism suffered from bilateral sensorineural impairment of hearing. The routine methods of audiological and molecular genetic examination were used throughout the study. RESULTS: As a result of molecular genetic studies, four out of the 20 patients were found to carry six recessive mutations of the SLC26A4 gene in the compound heterozygous and one such gene in the homozygous state which confirmed the hereditary nature of the disease. The children suffered the hearing loss of varying severity diagnosed at different age. The thyroid hypofunction in one child was identified when it was 2 years of age, and in two children at the age of 8 and 9 years. CONCLUSION: The first step in the diagnosis of the Pendred syndrome among children with congenital hearing loss was a CT scan of the temporal bones that showed incomplete separation of the curls of the cochlea and enlarged vestibular aqueduct. It is necessary to continue to study epidemiology, clinical and molecular genetics of the Pendred syndrome in the Russian population.

[Johanson-Blizzard syndrome: audiological features and results of cochlear implantation].

Johanson-Blizzard syndrome is a rare congenital autosomal recessive disease characterized by the association of congenital deficiency of the exocrine pancreatic function and multiple malformations. One of the most common manifestations of this pathology is sensorineural hearing loss of different severity and anomalous development of the inner ear. The case of cochlear implantation in the patient presenting with bilateral sensorineural deafness, congenital malformation of the inner ear, and stenosis of the internal auditory canal is reported.

[Cochlear implantation in immunocompromised patients].

This paper reports a clinical case that gives evidence of the possibility of cochlear implantation after liver transplantation. Patient K. aged 3 years 10 months was admitted to the Russian Research and Practical Centre of Audiology and Hearing Rehabilitation with the diagnosis of type IB glycogenosis after maternal liver transplantation associated with chronic neutropenia, chronic cutaneous and mucosal infection, partial symptomatic partial epilepsy, retarded psycho-motor development, and complaints of the absence of auditory response. The audiological examination provided materials for the diagnosis of grade IV bilateral sensorineural hearing loss tending toward deafness. Cochlear implantation recommended to the patient was performed on February 20, 2013 using the HiRes 90 K implant with the HiFocus Helix electrode (Advanced Bionics, USA). The surgical intervention and the postoperative period passed without complications. The speech processor was activated one month after surgery. The results of surdopedagogical testing gave evidence of successful rehabilitation promising the further improvement. It is concluded that immunosuppressive therapy is not an absolute contraindication for cochlear implantation, but this procedure requires detailed examination and thorough preparation for the forthcoming surgery.