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.

[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.

[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.

[The analysis of acoustic activity unsynchronized with the stimulus with the use of TEOAE]. / Analiz akusticheskoi aktivnosti, ne sinkhronizirovannoi so stimulom, pri registratsii zaderzhannoi vyzvannoi otoakusticheskoi emissii.

The presence of ambient noise or the troubled child's behavior during the registration of transiently induced optoacoustic emission (TEOAE) can lead to false positive results at the first stage of hearing screening. The aim of this study is to evaluate the effectiveness of the noise reduction method based on weighted averaging of the data in the frequency and time slot, to check TEOAE, and to improve the effectiveness of universal hearing screening. Particular attention is paid to the analysis of the origin of noise recorded during the UAE. PATIENTS AND METHODS: We have developed a method of noise reduction, based on weighted averaging of the data in the frequency and time cells. In this study, 20 people were examined (9 adults and 11 children). TEOAE was performed using the probe of the ILO 288 instrument manufactured by Otodinamics Ltd. that was connected to the E-MU 0204 sound card. The probe microphone was connected through the preamplifier to one input channel of the sound card, and the second channel was used to receive a signal from the ECG and the respiration recorder. Thereafter, the data thus obtained were processed by several methods, including the method of averaging in the frequency and time slot designed to average a set of implementations that contain a noisy signal. The comparison of the results of the use of noise suppression method based on weighted averaging of the data in the frequency and time cells showed that it increases the accuracy of TEOAE. MAIN RESULTS: Our work suggests that the use of the noise suppression method based on weighted averaging of the data in the frequency and time cells, increases the accuracy of TEOAE. Similar results were obtained by the weighted averaging method.

[New method for analysis and visualization of the fine temporal structure of the transient evoked otoacoustic emission signal].

We have developed the new method for the analysis and visualization of the fine temporal structure of the transient evoked otoacoustic emission signal. The method consists of the presentation of the signal in the form of a set of tone components with a rapidly changing amplitude and relatively stable frequency. It is based on the combination of three spectrograms differing in frequency and temporal resolution by means of fuzzy logic amplitude estimation with subsequent frequency refining with the use of the least square procedure, reduction of the number of the insignificant components, and final re-ordering of the results for the simplification of further data processing. The new method was named Pitch Envelope Analysis (PEA). For data representation, a new type of diagram named componentogram was designed. The proposed method can be used for the real time processing of the continuous data stream especially for speech processing.

Hand-held device for OAE-based screening.

In this paper, the main concepts realized in a handheld OAE device are described. These concepts are: weighted averaging, non-linear MLS technique, acoustic probe with flat response, electronic passport of the probe, communication with clinical databases, special language for device control.