Does Hypochlorous Acid Cause Ototoxicity? An Experimental Study.

AIM: Hypochlorous acid (HOCl) is a weak acid that ionizes in water. It is an effective antiseptic exhibiting low toxicity on living tissues. We aimed to investigate the ototoxic effects of HOCl on an animal model by using electrophysiological and histological methods. MATERIALS AND METHODS: The study comprised 32 Sprague-Dawley rats, which were separated into four groups: control group (A), saline solution group (B), 70% isopropyl alcohol + 2% chlorhexidine group (C), and HOCl group (D). After recording the auditory brainstem response (ABR) for basal hearing thresholds (8, 16, 24, and 32 kHz), 0.03 ml of the aforementioned materials was injected intratympanically three times every 2 days in groups B, C, and D. ABR measurements were repeated on the 7th and 21st days. All animals were sacrificed, and temporal bones were prepared for examinations of cochlear histology and vascular endothelial growth factor immunohistochemistry. RESULTS: Basal hearing levels were normal across all frequencies and groups, with no statistical differentiation. On the 7th and 21st days after the ABR test, all other groups demonstrated a significant deterioration in hearing levels compared with group A. When the results from 7th and 21st days were compared within group D, a partial recovery was observed. In histopathology, groups C and D demonstrated moderate and severe cochlear degeneration, along with decreased immunoreactivity in the organ of Corti, stria vascularis, and spiral ligament. CONCLUSION: This is the first study to evaluate the safety of using HOCl in otology. Although HOCI is less ototoxic than the disinfectant used, it may have a toxic effect on cochlea.Level of Evidence: Animal Research.

Behavioural and Electrophysiological Evaluation of Loudness Growth in Clinically Normal Hearing Tinnitus Patients with and without Hyperacusis.

INTRODUCTION: The common mechanism of tinnitus, hyperacusis, and loudness perception is hypothesized to be related to central gain. Although central gain increases with attempts to compensate hearing loss, reduced input can also be observed in those with clinically normal hearing. This study aimed to evaluate the loudness growth function of tinnitus patients with and without hyperacusis using behavioural and electrophysiological methods. METHODS: The study consists of three groups with a total of 60 clinically normal hearing subjects, including the control group (10 men and 10 women; mean age 39.8, SD 11.8 years), tinnitus group (10 men and 10 women; mean age 40.9, SD 12.2 years), and hyperacusis group (also have tinnitus) (7 men and 13 women; mean age 38.7, SD 14.6 years). Loudness discomfort levels (LDLs), categorical loudness scaling (CLS), and cortical auditory evoked potentials were used for the evaluation of loudness growth. N1-P2 component amplitudes and latencies were measured. RESULTS: LDL results of 500, 1,000, 2,000, 4,000, and 8,000 Hz showed a significant difference between the hyperacusis group and the other two groups (p < 0.001). In the loudness scale test performed with 500 Hz and 2,000 Hz narrow-band noise (NBN) stimulus, a significant difference was observed between the hyperacusis group and the other two groups in the "medium," "loud," and "very loud" categories (p < 0.001). In the cortical examination performed with 500 Hz and 2,000 Hz NBN stimulus at 40, 60, and 80 dB nHL intensities, no significant difference was observed between the groups in the N1, P2 latency, and N1-P2 peak-to-peak amplitude. CONCLUSION: Although the hyperacusis group is significantly different between groups in behavioural tests, the same cannot be said for electrophysiological tests. In our attempt to differentiate tinnitus and hyperacusis with electrophysiological tests over the loudness growth function, N1 and P2 responses were not seen as suitable methods. However, it appears to be beneficial to use CLS in addition to LDLs in behavioural tests.

Long-Term Effects of COVID-19 and the Pandemic on Tinnitus Patients.

This study aimed to explore the effect of COVID-19 and the pandemic period on the tinnitus-related complaints of patients with chronic tinnitus. Ninety-six patients who were diagnosed with chronic tinnitus before the pandemic were enrolled in this study. Before the pandemic and in January 2022, all patients used the Visual Analog Scale (VAS) to assess tinnitus loudness, annoyance, and effect on everyday life, sleep, and concentration. Additionally, patients filled the Tinnitus Handicap Inventory (THI) and the Hyperacusis Questionnaire (HQ). In the entire cohort, tinnitus loudness, annoyance, and tinnitus-induced difficulties with concentration as well as THI and HQ scores increased significantly during the two pandemic years. Thirty-seven tinnitus patients contracted COVID-19 between March 2020 and January 2022. These patients were asked to list leading COVID-19 symptoms, changes in tinnitus complaints during and after the disease, and whether their hearing abilities were affected. Three patients in the COVID-19 group confirmed worsening their hearing abilities. There was no decrease in the tinnitus complaint during COVID-19, 24.3% of the infected patients reported exacerbation of tinnitus, and 75.7% said tinnitus remained the same. In the COVID-19-negative group, 13.5% reported tinnitus decrease during the pandemic, 57.6% said it remained the same, and 28.8% reported exacerbation of tinnitus. When split into infected and non-infected groups, a significant increase in tinnitus loudness, tinnitus effect on concentration, and THI scores were seen only in patients who contracted COVID-19, while hyperacusis worsened significantly (p < 0.05) only in COVID-19-negative tinnitus patients. Despite significant differences within the groups, there were no differences found between the groups. This study points to possible different effects of the infection with SARS-CoV-2 and the pandemic period on patients with chronic tinnitus. It also provides evidence for deterioration of preexisting tinnitus as a possible long-term effect of COVID-19.

Prevalence of and factors affecting otitis media with effusion in children in the region from Balkans to Caspian basin; A multicentric cross-sectional study.

OBJECTIVE: The aim of our study was to contribute to the literature about the prevalence of OME by conducting a research in a wide geography examining most of the associating factors together with a questionnaire. Additionally, possible effects of altitudes and latitudes, concordance between the otoscopic examination findings and tympanometric and acoustic reflex test results were evaluated in 4-7 years old children in the same season in different countries. METHODS: In the randomly sampled schools from different regions of different cities where people of different scoioecomonic statuses live, 4-7 year-old children were included in the study. The results of the questionnaire covering the potential factors in OME etiology were evaluated together with the results of the otoscopic examination and tympanometry findings, and also the acoustic reflex findings to direct the interpretation in cases of low amplitude - blunted peak tympanograms which can be interpreted as a "Type B" or "Type As". All the results were gathered in the same season. RESULTS: Ten centers from nine countries participated in the study. A total of 4768 children were evaluated. The frequency of OME diagnosed by otosopic examination was 22.48% (n=1072) and the diagnosis rate when otoscopic examination plus type B tympanometry were taken into account was found as 11.3% (n=539) in general population. Factors increasing the prevalence of OME were found as; mother's educational level (p=0.02), child's age (p=0.006), history of upper respiratory tract infection (p=0.001), smoking father (p=0.01), mother being a housewife or laborer (p=0.01), history of allergy (p=0.001), asthma (p=0.04), or allergy symptoms (p=0.02). No direct relationship was found between altitudes or latitudes and prevalence of OME. CONCLUSION: The important affecting factors found after analyzing all of the potential risk factors in the same model are secondhand smoke exposure, low level of mother's education, mother's occupation, positive history of URTI, and age of the child being less than 7. By paying attention to the factors that increase the prevalence of OME, putting particular emphasis on the preventable ones such as smoking, education, and fighting with allergies could decrease the prevalence of this public health issue.

The Protective Effect of Nigella sativa Oil against Experimentally Induced Cisplatin Ototoxicity: An Animal Study.

OBJECTIVES: The objective of this study was to investigate the potential protective effect of Nigella sativa oil (NSO) against cis-diamminedichloroplatinum or cisplatin (CDDP)-induced ototoxicity. MATERIALS AND METHODS: Twenty-four Wistar albino rats were randomly and equally divided into four groups. Groups 1 and 2 were given a total of 15 mg/kg CDDP intraperitoneally, which was divided equally into three doses on days 1, 3, and 5. Group 2 was treated via gavage feeding with 15 ml NSO that was divided into five doses on days 1, 3, 5, 7, and 9. Groups 3 and 4 received only 15 ml of NSO and 15 ml of 0.9% saline solution, respectively, which were orally administered and divided into five doses on days 1, 3, 5, 7, and 9. Baseline high-frequency (8, 12, 16, and 32 kHz) auditory brainstem response (ABR) measurements were collected in all the groups before the medical administrations and were repeated on the 14th day before sacrifice. Afterward, a histopathological evaluation of the cochlea was performed. RESULTS: There was a significant difference in the histopathological changes between group 1 and the other groups (p<0.01). Changes in the spiral ganglion cells, the stria vascularis, and the external ciliated cells were significantly different between groups 1 and 2 (p=0.019, 0.039, and 0.045, respectively). The ABR results revealed significant differences in the 16 and 32 kHz measurements between groups 1 and 2 (p=0.013 and p<0.01, respectively). CONCLUSION: According to the results, NSO may have a protective effect on cochlear function against the disruptive effects of CDDP in rats.

Turkish Adaptation of Khalfa Hyperacusis Questionnaire.

OBJECTIVE: The aim of this study is to adapt Khalfa Hyperacusis Questionnaire (HQ) into Turkish for the use in the diagnosis and treatment of patients with hyperacusis. METHOD: HQ and Beck Anxiety Inventory (BAI) were administered to a total of 529 participants (320 female, 209 male), aged 18 to 73 (mean age: 29.76±10.59) years who were randomly selected from the general population. For the evaluation of the data, confirmatory and exploratory factor analysis, correlation analysis, descriptive statistics, t-test, analysis of variance, and Sidak correction test were used. RESULTS: In the reliability analysis, the Cronbach's alpha (aC) internal consistency coefficient was found to be 0.81. Factor analysis revealed three subdimensions (attentional, social, and emotional). The total variance of these three subdimensions were 63%, and the internal consistency of the subdimensions was also high (αC >0.70). Confirmatory factor analysis and structural equation modeling results indicated that three-factor solutions with 14 items met the criteria for the adequacy of fit among the Turkish patients. The mean score for hyperacusis was estimated as 15.69±6.63 points.There was a positive, weak, but significant association between hyperacusis and anxiety (r=0.357, p=0.01, p<0.05). The patients who were exposed to noise were found to have higher levels of hyperacusis, compared to those who were not (t=6.78, p=0.01, p<0.05). The patients who had decreased noise tolerance over time were found to be higher hyperacusis levels than those without (t=4.83, p=0.01, p<0.05). CONCLUSION: Based on these measurements, 14 questions and three-factor solutions were found to be a valid and reliable tool.