scholarly journals Hearing Function in Heterozygous Carriers of a Pathogenic GJB2 Gene Mutation

2013 ◽  
pp. 323-330 ◽  
Author(s):  
D. GROH ◽  
P. SEEMAN ◽  
M. JILEK ◽  
J. POPELÁŘ ◽  
Z. KABELKA ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Gjb2 Gene ◽  
Frequency Range ◽  
Distortion Product ◽  
Hearing Function ◽  
Extended Frequency Range ◽  
Extended Frequency ◽  
Heterozygous Carriers ◽  
35Delg Mutation ◽  
Age And Sex

The most frequent hereditary hearing loss is caused by mutations in the GJB2 gene coding for the gap junction beta 2 protein Connexin 26 (Cx26). In contrast to many studies performed in patients with bi-allelic mutations, audiometric studies on heterozygotes are sparse and often contradictory. To evaluate hearing function in heterozygous carriers of the GJB2 c.35delG mutation, audiometry over the extended frequency range and the recording of otoacoustic emissions (OAEs), i.e., transient-evoked OAEs (TEOAEs) and distortion product OAEs (DPOAEs), were performed in a group of parents and grandparents of deaf children homozygous for the GJB2 c.35delG mutation. The comparison of audiograms between control and heterozygous subjects was enabled using audiogram normalization for age and sex. Hearing loss, estimated with this procedure, was found to be significantly larger in GJB2 c.35delG heterozygous females in comparison with controls for the frequencies of 8-16 kHz; the deterioration of hearing in heterozygous men in comparison with controls was not statisticaly significant. A comparison of TEOAE responses and DPOAE levels between GJB2 c.35delG heterozygotes and controls did not reveal any significant differences. The results prove the importance of using audiometry over the extended frequency range and audiogram normalization for age and sex to detect minor hearing impairments, even in a relatively small group of subjects of different ages.

scholarly journals Estimation of auditory threshold in an extended frequency range in elderly people

2019 ◽  
Vol 4 (4) ◽  
pp. 4-7
Author(s):  
Lubov V. Aizenshtadt ◽  
Tatyana Yu. Vladimirova ◽  
Alexandr V. Kurenkov ◽  
Anastasia M. Kashapova
Keyword(s):  
Hearing Loss ◽  
Age Group ◽  
Auditory Function ◽  
Frequency Range ◽  
Auditory Thresholds ◽  
High Frequencies ◽  
Age Related ◽  
Hearing Thresholds ◽  
Extended Frequency Range ◽  
Extended Frequency

Objectives - to study hearing thresholds at high frequencies in elderly and senile patients, taking into account the age norm and the presence of comorbid diseases. Material and methods. 111 patients aged from 50 to 97 years (mean age 70.5 ± 2.1) were examined, their age, auditory function, and concomitant diseases were also registered. Results. The measured average auditory thresholds at high frequencies, if compared to the age-related standards for auditory sensitivity, have revealed an underestimated hearing loss in 12.6% of patients. The presence of concomitant diseases has a significant impact on the development of chronic sensorineural hearing loss in each age group. Conclusion. Audiometry in an extended frequency range in elderly patients with concurrent diseases can improve the hearing examination algorithm.

Otoacoustic emissions in patients with hypotension

2003 ◽  
Vol 117 (4) ◽  
pp. 265-269 ◽  
Author(s):  
Dimitrios G. Balatsouras ◽  
Stavros Korres ◽  
Nikola Simaskos ◽  
Dimitrios Kandiloros ◽  
Eleftherios Ferekidis ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Hearing Loss ◽  
Systolic Blood Pressure ◽  
Otoacoustic Emissions ◽  
Distortion Product Otoacoustic Emissions ◽  
Frequency Range ◽  
Distortion Product ◽  
Cochlear Damage ◽  
Lower Frequency Range ◽  
Age And Sex

The aim of this study was to investigate the relation between hypotension and slowly developing hearing impairment, using otoacoustic emissions. A group of 42 patients was examined, with diastolic blood pressure ≤60 mmHg and systolic blood pressure ≤105 mmHg. The subjects underwent biochemical, cardiological, ENT and audiological examinations. Distortion product otoacoustic emissions (DPOAE) were recorded in the format of DP-gram. The results were compared to the data of 30 normal persons of similar age and sex, examined at the same laboratory. Audiometric results showed that 18 patients had mild or moderate symmetrical hearing loss in one or more frequencies, mainly in the lower frequency range. DPOAE of the patients had reduced amplitude as compared to controls or were even absent, in one or more frequencies. It may be concluded that a hypotensive condition could be a possible factor in the origin of cochlear damage and DPOAE may be useful in monitoring hypotensive patients.

The working standard of the unit of power of electromagnetic waves in the frequency range from 37,5 to 220 GHz

2020 ◽  
pp. 53-58
Author(s):  
A. V. Koudelny ◽  
I. M. Malay ◽  
V. A. Perepelkin ◽  
I. P. Chirkov
Keyword(s):  
Microwave Power ◽  
Electromagnetic Waves ◽  
Primary Standard ◽  
The State ◽  
Frequency Range ◽  
Working Standard ◽  
Extended Frequency Range ◽  
Effective Efficiency ◽  
Extended Frequency ◽  
Good Agreement

The possibility of using bolometric converters of microwave power from the State primary standard of the unit of power of electromagnetic waves in waveguide and coaxial paths GET 167-2017, which has a frequency range from 37,5 to 78,33 GHz, in an extended frequency range up to 220 GHz, is shown. Studies of semiconductor bolometric converters of microwave power in an extended frequency range have confirmed good agreement and smooth frequency characteristics of the effective efficiency factor of the converters. Based on the research results, the State working standard of the unit of power of electromagnetic waves of 0,1–10 mW in the frequency range from 37,5 to 220 GHz 3.1.ZZT.0288.2018 was approved. The technical characteristics of the working standard of the unit of power of electromagnetic oscillations in an extended frequency range from 37,5 to 220 GHz are given.

Simulation of Real-Time Frequency Estimators for Pulsed Doppler Systems

1986 ◽  
Vol 8 (4) ◽  
pp. 252-271 ◽  
Author(s):  
G.H. van Leeuwen ◽  
A.P.G. Hoeks ◽  
R.S. Reneman
Keyword(s):  
Real Time ◽  
Instantaneous Frequency ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Zero Crossings ◽  
Time Frequency ◽  
Doppler Signals ◽  
Extended Frequency Range ◽  
Extended Frequency ◽  
Frequency Detector

Four time-domain oriented, real-time frequency estimators, based on the detection of phase, zero-crossings, instantaneous frequency or autocorrelation, were simulated on a digital computer and subjected to computer generated Doppler signals, enabling the investigation of the influence of spectral shape, filtering, frequency shift, noise and quantization. Three estimators, the autocorrelator as well as the instantaneous frequency detector and the autocorrelator, both with extended frequency range, appeared to be very accurate. They exhibit a bias in the estimator output of less than 2 percent over a wide frequency range, the former up to nearly the Nyquist frequency, the latter two beyond, even for skew spectra and under poor signal conditions regarding bandwidth and noise.

scholarly journals Spectrum and Frequency of the GJB2 Gene Mutations Among Latvian Patients with Prelingual Nonsyndromic Hearing Loss

2009 ◽  
Vol 63 (4-5) ◽  
pp. 198-203
Author(s):  
Olga Šterna ◽  
Natālija Proņina ◽  
Ieva Grīnfelde ◽  
Sandra Kušķe ◽  
Astrīda Krūmiņa ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Gene Mutations ◽  
Gjb2 Gene ◽  
Connexin 26 ◽  
Compound Heterozygous ◽  
Nonsyndromic Hearing Loss ◽  
Profound Hearing Loss ◽  
Common Cause ◽  
Gjb2 Mutation ◽  
35Delg Mutation

Spectrum and Frequency of the GJB2 Gene Mutations Among Latvian Patients with Prelingual Nonsyndromic Hearing Loss Mutations in the GJB2 gene (connexin 26) are the most common cause of congenital nonsyndromic severe-to-profound hearing loss. Sixty-five hearing impaired probands from Latvia were tested for mutations in the GJB2 gene to determine the percentage of hearing loss attributed to connexin 26 and the types of mutations in this population. A total of 62% of patients tested had GJB2 mutations. Four different mutations in the GJB2 gene were identified in Latvian patients with nonsyndromic sensorineural hearing loss: 35delG, 311-324del14, 235delC and M34T. The most prevalent mutation is 35delG (47% of all probands were homozygous and 8% compound heterozygous). Our findings support the conclusion that the 35delG mutation is the most prevalent GJB2 mutation and that it is the common cause of hereditary nonsyndromic hearing loss in populations of European descent.

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