Wideband Tympanometry: Normative Data for Young Iranian Adults.

INTRODUCTION: The middle ear sound transmission features can impact acoustic sounds reaching the inner ear. Wideband tympanometry (WBT) or wideband acoustic immittance is an effective and desirable measurement of conductive conditions in newborns and adults and has appropriate sensitivity to distinguish different pathologies like otosclerosis from other middle ear conflicts. Recently, there has been an increased utilization of WBT, which highlights the importance of collecting population-based normative data as a necessary step in the standardization of this test, as well as for its clinical application. This study aimed to obtain normative data on WBT in the adult Iranian ethnic. METHODS: There were 101 participants (202 ears) consisting of 53 males (57.4%) and 48 females (42.6%) in the age range of 19-29 years. The Titan WBT device (Interacoustics, Assens, Denmark) was used for WBT measurements. The broadband click was utilized as the probe tone between frequencies of 250 Hz and 8,000 Hz. All the participants underwent ear, nose, and throat assessments, pure-tone audiometry, and conventional tympanometry (226 Hz). Features like equivalent ear canal volume (Veq), tympanometric peak pressure, gradient, resonance frequency (RF), energy absorbance (EA), and admittance (Ad) were tested. RESULTS: In this cross-sectional study, 202 ears were tested for WBT. EA increased by frequency enhancement; at 1 kHz and 2 kHz the EA was the most prominent; at 2,519 Hz, it started decreasing, and at 8 kHz, there was a slight increase. There was also a significant difference in the Veq and Ad between males and females. Studies have shown that the Veq may vary between male and female subjects based on body size. CONCLUSION: In this study, normative data for the WBT were obtained from young Iranian adults with normal hearing ranges and middle ear conditions. We hope that this study and the resulting norm will provide a basis for increasing the use of WBT in Iranian diagnostic and clinical practices.

A novel pathogenic variant in the LRTOMT gene causes autosomal recessive non-syndromic hearing loss in an Iranian family.

BACKGROUND: Hearing loss (HL) is the most common sensorineural disorder with high phenotypic and genotypic heterogeneity, which negatively affects life quality. Autosomal recessive non-syndromic hearing loss (ARNSHL) constitutes a major share of HL cases. In the present study, Whole exome sequencing (WES) was applied to investigate the underlying etiology of HL in an Iranian patient with ARNSHL. METHODS: A proband from an Iranian consanguineous family was examined via WES, following GJB2 sequencing. WES was utilized to find possible genetic etiology of the disease. Various Bioinformatics tools were used to assess the pathogenicity of the variants. Co-segregation analysis of the candidate variant was carried out. Interpretation of variants was performed according to the American College of Medical Genetics and Genomics (ACMG) guidelines. RESULTS: WES results showed a novel frameshift (16 bp deletion) variant (p.Ala170Alafs*20) in the LRTOMT gene. This variant, which resides in exon 6, was found to be co-segregating in the family. It fulfils the criteria set by the ACMG guidelines of being pathogenic. CONCLUSION: Here, we report successful application of WES to identify the molecular pathogenesis of ARNSHL, which is a genetically heterogeneous disorder, in a patient with ARNSHL.

Ear surgery techniques results on hearing threshold improvement.

BACKGROUND: Bone conduction (BC) threshold depression is not always by means of sensory neural hearing loss and sometimes it is an artifact caused by middle ear pathologies and ossicular chain problems. In this research, the influences of ear surgeries on bone conduction were evaluated. MATERIALS AND METHODS: This study was conducted as a clinical trial study. The ear surgery performed on 83 patients classified in four categories: Stapedectomy, tympanomastoid surgery and ossicular reconstruction partially or totally; Partial Ossicular Replacement Prosthesis (PORP) and Total Ossicular Replacement Prosthesis (TORP). Bone conduction thresholds assessed in frequencies of 250, 500, 1000, 2000 and 4000 Hz pre and post the surgery. RESULTS: In stapedectomy group, the average of BC threshold in all frequencies improved approximately 6 dB in frequency of 2000 Hz. In tympanomastoid group, BC threshold in the frequency of 500, 1000 and 2000 Hz changed 4 dB (P-value < 0.05). Moreover, In the PORP group, 5 dB enhancement was seen in 1000 and 2000 Hz. In TORP group, the results confirmed that BC threshold improved in all frequencies especially at 4000 Hz about 6.5 dB. CONCLUSION: In according to results of this study, BC threshold shift was seen after several ear surgeries such as stapedectomy, tympanoplasty, PORP and TORP. The average of BC improvement was approximately 5 dB. It must be considered that BC depression might happen because of ossicular chain problems. Therefore; by resolving middle ear pathologies, the better BC threshold was obtained, the less hearing problems would be faced.

Whole-Exome Sequencing Identifies a Recurrent Small In-Frame Deletion in MYO15A Causing Autosomal Recessive Nonsyndromic Hearing Loss in 3 Iranian Pedigrees.

BACKGROUND: Hearing loss (HL) is the most prevalent and genetically heterogeneous sensory disabilities in humans throughout the world. METHODS: In this study, we used whole-exome sequencing (WES) to determine the variant causing autosomal recessive nonsyndromic hearing loss (ARNSHL) segregating in 3 separate Iranian consanguineous families (with 3 different ethnicities: Azeri, Persian, and Lur), followed by cosegregation analysis, computational analysis, and structural modeling using the I-TASSER (Iterative Threading ASSEmbly Refinement) server. Also, we used speech-perception tests to measure cochlear implant (CI) performance in patients. RESULTS: One small in-frame deletion variant (MYO15A c.8309_8311del (p.Glu2770del)), resulting in deletion of a single amino-acid residue was identified. We found it to be cosegregating with the disease in the studied families. We provide some evidence suggesting the pathogenesis of this variant in HL based on the American College of Medical Genetics (ACMG) and Genomics guidelines. Evaluation of auditory and speech performance indicated favorable outcome after cochlear implantation in our patients. CONCLUSIONS: The findings of this study demonstrate the utility of WES in genetic diagnostics of HL.

Cigarette smoking effect on human cochlea responses.

BACKGROUND: Smoking is one of the most important risk factor in increasing of non-communicable disorders, especially chronic diseases such as cancer, stroke, heart and respiratory diseases. Cigarette smoking could damage the cochlea and causing hearing loss. The otoacoustic emission (OAE) is a source of information for determining cochlear responses to sound stimuli and how to change the response of the auditory system in some diseases. OAE test was sensitive to outer hair cells (OHCs) activity. MATERIALS AND METHODS: In this study, tried to evaluate a hearing threshold of the smoker group versus non-smoker ones through pure tone audiometery, transient evoked otoacoustic emission (TEOAE) and distortion product otoacoustic emission (DPOAE) tests. RESULTS: The results indicated that significant decrement of 8000 Hz threshold, reduced DPOAE/TEOAE amplitude in the smoker group than non-smoker one (P < 0.05). DPOAE amplitudes decline reflects the cochlear damage caused by smoking. CONCLUSION: OAEs test was clinically non-invasive, accurate, and objective evaluation of the performance of cochlear OHCs.