Distortion Product Otoacoustic Emission Values Research Articles

Ototoxicity of Topical Castellani Solution and Boric Acid in Alcohol: an Experimental Study on Rats.

The aim of this study is to determine the ototoxicities of boric acid in alcohol (BAA) and Castellani solutions by means of distortion product otoacoustic emission (DPOAE). A total of 28 rats were randomly divided into four groups, each group consisting of 7 animals. Then, 0.1mL Castellani solution, 0.1mL BAA (4% boric acid solution prepared with 60% alcohol), 0.2mL (40mg/mL) gentamicin and 0.2mL saline were dropped to right outer ear canals of rats in groups 1, 2, 3 and 4 respectively, twice a day, for 14days. DPOAE values obtained on days 0 and 14 were statistically compared for the values obtained at 750-8000Hz frequencies. A statistically significant decrease was found on day 14 compared to day 0 values in Castellani group at all frequencies (p < 0.05). In BAA group, there was a statistically significant decrease between frequencies 1500 and 8000Hz on day 14 (p < 0.05).We found that Castellani and BAA were ototoxic. BAA and Castellani solutions should be avoided in patients with tympanic membrane perforations, ventilation tubes and open mastoid cavities.

Effects of Oxygen Therapies in Experimental Acute Acoustic Trauma.

Background: Acute acoustic trauma is defined as a sudden sensorineural hearing loss that occurs after an exposure to acoustic overstimulation. Increasing the oxygen in perilymph can be a treatment modality. Our study aims to investigate the influence of normobaric oxygen therapy on the recovery of acute acoustic trauma and to compare it with the hyperbaric oxygen therapy.Methods:Three groups of rats (5 rats each) were exposed to white noise for 1 hour. Sensorineural hearing loss was identified using distortion product otoacoustic emission. Subsequently, the first group was treated with hyperbaric oxygen therapy, the second group was treated with normobaric oxygen therapy, and the third group did not receive any treatment and was used as a control group.Results:There was a statistically significant difference within time for frequencies of 1, 1.5, and 2 kHz, but there was no statistically significant difference between groups. For frequencies of 3, 4, 5, and 6 kHz, there was a statistically significant difference within time and between groups. Between groups, recovery of distortion product otoacoustic emission values in all frequencies was better in the control group by the third, fifth, and seventh days. Comparing the values of hyperbaric oxygen therapy and normobaric oxygen therapy groups, it was observed that by the third day, the hyperbaric oxygen therapy values were better than those of the normobaric oxygen therapy values. However, by the fifth and seventh days, the normobaric oxygen therapy values were better (except at a frequency of 1 kHz).Conclusion:Because there is a high rate of spontaneous recovery, physicians should be more selective to treat patients with oxygen therapies.

Effect of Radiofrequency Waves of Mobile Phones on Distortion Product Otoacoustic Emissions

Abstract Objective The prolonged exposure to electromagnetic fields of mobile phones can damage the cochlear hair cells, which can be detected by otoacoustic emission (OAE). To know the effect of mobile phones on hearing, the young volunteers were subjected to prolonged mobile phone usage and changes in OAE were recorded. Materials and Methods Twenty-eight volunteers with normal hearing were made to talk one full hour continuously on the mobile phone. Distortion product otoacoustic emission (DPOAE) was measured prior to the usage of mobile phones and immediately after the use (post-exposure 1) and 24 hours after the use (post-exposure 2). The values were compared. Results Out of the 28 volunteers, 20 were females and 8 were males. Twenty-one volunteers preferred the right ear while using mobile phones, 7 preferred the left ear. There was no statistically significant difference between the baseline DPOAE values and values of post-exposure 1 and 2 when only the preferred ear was taken into consideration. When the preferred ear was compared with nonpreferred ear, a statistically significant difference was found only in the low frequencies between the pre-exposure and post-exposure 1 values. Conclusion This study shows there was no significant correlation between OAE and prolonged mobile phone exposure when the preferred ear was not considered.

Investigation Of Outer Hair Cell Function Of The Cochlea in Psoriasis Patients

Objective: Psoriasis has been accepted as a T-cell mediated systemic disease and systemic inflammation may also cause immune-mediated hearing loss. We aimed to evaluate cochlear function with otoacoustic emission (OAE) measurement in psoriasis patients, and to evaluate whether there is a relationship between the duration and severity of the disease and OAEs. Material and Methods: Forty-four patients diagnosed with psoriasis were included in the study. The control group consisted of 35 healthy volunteers. The patients' age, gender, onset age and duration of the disease, family history and additional diseases were questioned and psoriasis area severity index (PASI) was calculated. Audiological and otological evaluations were performed. Distortion Product Otoacoustic Emission (DPOAE) were measured at 500, 1000, 2,000, 4,000, 6000, 8000 and 10000 Hz frequencies. Results: There was no significant difference in DPOAE values at 500, 1000, 2000, 4000, 6000, 8000 and 10000 Hz between healthy volunteers and psoriasis patients. There was a significant difference between PASI score and DPOAE value at 1000 Hz, disease duration and DPAOE values at 4000 and 6000 Hz. Conclusion: Considering that psoriasis is a long-term, chronic systemic disease, patients should be follow-up closely even if they do not have hearing complaints in the early period, and as the duration and severity of the disease increases, the hearing of the patients may be affected.

Effect of Using N95 and Surgical Masks on Otoacoustic Emission in Cochlear Outer Hair Cells.

Distortion product otoacoustic emission (DPOAE) was measured to investigate the effect of mask use and type on oxygen saturation on cochlear function in health care professionals during the COVID-19 pandemic. Group 1 participants wore surgical masks; Group 2 participants wore N95 masks. Distortion product otoacoustic emission and oxygen saturation were measured in both groups before and after mask use. Comparison of signal-to-noise ratio (SNR) values before and after surgical mask use in DPOAE measurements of group 1 revealed statistically significant difference in the right and left ears. Comparison of the SNR values in DPOAE measurements of group 2 before and after 8 hours of N95 mask use revealed statistically significant differences in the right ear at 988, 2963, 4444, and 8000 Hz and in the left ear at 8000 Hz. We found that prolonged mask use may affect the outer hair cells in the cochlea, causing deterioration in DPOAE values.

Correlation of SOD and MDA Expression in the Organ of Corti and Changes in the Function of Outer Hair Cells Measured by DPOAE Examination in Noise-Exposed Rat Cochlea.

Hearing loss due to noise can cause the disturbances toward the quality of life and cause mechanical damage and metabolic decompensation. Distortion Product Otoacoustic Emission (DPOAE) is an examination to assess the sensory function of outer hair cells. Superoxide Dismutase (SOD) and Malondialdehyde (MDA) are markers of oxidative stress. The aim of this study was to identify the correlation between DPOAE examination and SOD and MDA expression in rats exposed to noise. This research was conducted on 27 rats which were divided into 3 groups, group 1 (control), group 2, and group 3 were groups with 100 dB and 110 dB noise exposure respectively. Our findings show a decrease in SOD expression and DPOAE values as well as an increase in MDA expression in rats exposed to noise and there is a positive correlation between Signal to Noise Ratio (SNR) value with SOD expression (r= 0.733, p= 0.025) and a negative correlation between SNR value with MDA expression (r= -0.678, p= 0.045). our study find the correlation of oxidant and antioxidant status values in the organ of corti and changes in the function of outer hair cells in noise-exposed rat models.

Effects of acute hypoxia on auditory pathway of Wistar albino rats

Background/aimIschemia is insufficient blood flow to provide adequate oxygenation. In the present study, we aimed to show whether acute hypoxia has a critical oxygen value that may lead to the deterioration of cochlear function.Materials and methodsUnder general anesthesia, prehypoxic signal-to-noise ratios were determined by distortion product otoacoustic emissions (DPOAE). The oxygen saturation (SaO2) values ​​of rats were monitored with an oxygen saturation probe. Rats were injected with an extra dose of anesthetic agent, and SaO2 was reduced. DPOAE values ​​in SaO2 100–90, 90–80, 80–70, and 70–60 posthypoxic values​ were measured and compared statistically with prehypoxic values.ResultsAt 3000 and 4000 Hz, SaO2 70–60 values measured after the hypoxia were observed to be statistically significantly lower than the values measured before the hypoxia. At 6000 and 8000 Hz, SaO2 80–70 and 70–60 values measured after the hypoxia were observed to be statistically significantly lower than the values measured before the hypoxia. At 10,000 Hz, all of the values measured after the hypoxia were observed to be statistically significantly lower than the values obtained before the hypoxia.ConclusionMany studies have been conducted on the effects of hypoxia on the inner ear. It remains unclear how fluctuations in DPOAE levels affect hearing in clinical trials when the SaO2 starts to decrease. Although hypoxia has been implicated in the etiology of sudden hearing loss and tinnitus, the effects of acute hypoxia on the cochlea are still uncertain. Further studies are needed on this subject.

Protective effect of creatine on amikacin-induced ototoxicity

IntroductionAminoglycosides are widely known for their ototoxic side effects. Nevertheless, they are potent antibiotics used in the treatment of life-threatening conditions because of the current concern for antibiotic resistance. We hypothesized that creatine supplements which are believed to improve mitochondrial antioxidant defense system and maintain optimal energy homeostasis may improve the ototoxic side effects. ObjectiveThis study aimed to investigate the protective effects of creatine monohydrate against ototoxicity induced by amikacin in rats in an experimental animal model, using distortion product otoacoustic emissions and auditory brainstem response. MethodsTwenty healthy rats were assigned to four groups (5 rats in each): the control group, the creatine monohydrate group, the amikacin group and the amikacin+creatine monohydrate group. The creatine monohydrate group received creatine at a dose of 2g/kg once daily via gastric gavage for 21 days. The amikacin group received amikacin at a dose of 600mg/kg by intramuscular injections once daily for 21 days. The amikacin+creatine monohydrate group received intramuscular injections of amikacin (600mg/kg) once daily for 21 days and creatine monohydrate (2g/kg) once daily via gastric gavage for 21 days. The control group received nothing. The distortion product otoacoustic emissions and auditory brainstem response measurements were performed on all rats on days 0, 7, 21. ResultsRegarding auditory brainstem response values, a significant increase in the auditory threshold was observed in the amikacin group on day 21 (p< 0.001). The amikacin+creatine monohydrate group showed significantly lower levels of auditory brainstem response auditory thresholds on day 21 in comparison to the amikacin group (p< 0.001). Additionally, the control group and the amikacin+creatine monohydrate group did not differ significantly with respect to auditory brainstem response thresholds on treatment day 21 (p> 0.05). When we compare distortion product otoacoustic emissions values, there was no significant difference between the amikacin and amikacin+creatine monohydrate groups on day 7 (p> 0.05), However significantly greater distortion product otoacoustic emissions values were observed in the amikacin+creatine monohydrate group on day 21 compared to the amikacin group (p< 0.001). ConclusionOur findings demonstrate that creatine treatment protects against amikacin ototoxicity when given at a sufficient dose and for an adequate time period.

Protective effect of ethosuximide on hearing in NOD/LtJ mice via blockage of endogenous apoptosis

Purpose: To determine the protective effect of ethosuximide on the hearing of NOD/LtJ mice, and the underlying mechanism of action.&#x0D; Methods: The mice were randomly assigned to control and treatment groups (20 mice per group). Mice in the treatment group were administered ethosuximide intraperitoneally at a dose of 200mg/kg body weight (bwt), while those in the control group received an equivalent dose of saline via the same route. Both groups were subjected to auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE) tests, as well as determination of mRNA expressions of α1G, α1H, α1I, m-calpain, μ-calpain, and caspase-3.&#x0D; Results: At ages of 6 and 9 weeks, ABR values were significantly lower in the treatment group than those in the control group (p &lt; 0.05). At age 3, 6 and 9 weeks, control group DPOAE values were much lower than those in the treatment group. However, at signal frequency of 35344 Hz, DPOAE value was significantly reduced in the treatment group (p &lt; 0.05). There was significant down-regulation in mRNA expressions of α1G, α1H, α1I, m-calpain, μ-calpain and caspase-3, in the treatment group, when compared with the control group (p &lt; 0.05).&#x0D; Conclusion: Ethosuximide delays mice hearing loss and protects their hearing via a mechanism involving blockage of endogenous apoptotic pathways. This mechanism may provide guidance in the search for suitable new drugs.&#x0D; Keywords: Ethosuximide, Endogenous apoptosis, Hearing, Protection

Role of melatonin in prevention of age-related hearing loss.

IntroductionAge-related hearing loss (ARHL) is a consequence of aging of the auditory system. The best known mechanism of cell death in ARHL is apoptosis due to increased production of reactive oxygen species. In this context, it is hypothesized that melatonin, owing to its high antioxidant potential and its action in the mitochondria, helps prevent or delay outer hair cell dysfunction (HCD).AimsTo evaluate the effect of melatonin on the prevention of HCD dysfunction in the ARHL process in a susceptible murine C57BL/6J model.MethodC57BL/6J animals were divided into two groups: control (CG) and melatonin (MG). The CG received a saline and ethanol solution and the MG, melatonin (10 mg/kg/day). The solutions were offered daily (50 μl) orally over a 10-month period. Distortion Product Otoacoustic Emissions (DPOAE) measurements were conducted once a month.ResultsThere was a decrease in DPOAE values in both groups over time and a differentiation between them from the 10th month of life onwards. At 10 months, the MG maintained higher DPOAE values than the CG at all frequencies tested.ConclusionThe use of melatonin has otoprotective effects on HCD in the ARHL process in the C57BL/6J model.

Therapeutic effects of metformin for noise induced hearing loss.

This study aimed to investigate the healing effect of metformin on noise induced hearing loss (NIHL) by measuring audiological, biochemical and histological parameters. 32 rats were divided into four groups (Group 1: Noise, Group 2: Noise + Metformin, Grup 3: Metformin, Grup 4: Control). Broadband noise was applied to Group 1 and Group 2 after basal measurements. Measuring audiological (distortion product otoacoustic emission (DPOAE) and Auditory Brainstem Response (ABR)), biochemical (total antioxidant status (TAS), total oxidant status (TOS), oxidative status index (OSI), DNA damage, IL-1 beta, IL-6, TNF alfa, HSF-1 and COX-2) and histological parameters. Group 2 had significant decreases in ABR thresholds on day 7 and day 14 compared to day 1. DPOAE values of Group 2 on the 7th and 14th days were significantly higher than the post-noise levels. DNA damage, TOS and OSI values of Group 1 were significantly higher than the other groups. The Cox-2 value of Group 1 was higher than all other groups. The HSF-1 value of Group 2 was significantly higher than that of Group 1. In terms of IL-1 Beta, IL-6 and TNF-alpha values, there was no significant difference between groups 2, 3 and 4 and these values were significantly lower than group 1. In histopathological results of our study, no significant difference was found between the groups being exposed to noise and the control group. This study showed that early period of Metformin treatment has therapeutic effect on NIHL.

Assessment of auditory function and lipid levels in patients receiving oral isotretinoin (13-cis retinoid) therapy for acne vulgaris.

IntroductionIsotretinoin (13-cis retinoid) is a synthetic retinoid. It was approved by the FDA in 1982 for use of oral isotretinoin in severe acne. It is also used in moderate-severe acne that does not respond to conventional treatments. Isotretinoin is the only available drug that affects all stages of acne pathogenesis.AimTo prospectively investigate whether there is an effect of isotretinoin therapy on auditory function and, if so, to demonstrate its association with simultaneous blood lipid levels.Material and methodsThirty patients (60 ears) with acne vulgaris, who received 0.5 mg/kg of isotretinoin therapy, were included in the study. Distortion product otoacoustic emissions (DPOAEs) and pure tone audiometry tests were performed to evaluate auditory function at the beginning of the procedure and the 6th month of treatment. In addition, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol, triglyceride, high-density lipoproteins (HDL) and low-density lipoproteins (LDL) cholesterol levels were recorded.ResultsThere was no statistically significant difference between pre-treatment and post-treatment mean pure tone audiometry threshold and DPOAE values; however, the increase in total blood cholesterol, triglyceride and LDL levels and the decrease in HDL levels were statistically significant.ConclusionsAccording to our study findings, isotretinoin did not cause worsening of the bilateral hearing threshold, but increased blood lipid levels. There is no need for follow-up auditory functions in routine practice during therapy, but blood lipid levels should be monitored.

The effect of resveratrol on the histologic characteristics of the cochlea in diabetic rats.

The aim of this study was to investigate changes in the cochlea and the potential dose-dependent effects of resveratrol (RSV) against diabetes mellitus (DM) ototoxicity. Animal model. Twenty-four male Wistar albino rats were divided into four groups. Baseline distortion product otoacoustic emission (DPOAE) measurements were evaluated. Group I was the control group, group II was made diabetic with single-dose streptozotocin, and groups III and IV were rendered diabetic as group II and administered 10 and 20 mg RSV, respectively, intraperitoneally for 4 weeks. All animals were sacrificed after repeated DPOAE measurement. Apoptosis was investigated using caspase-3, Bax (Bcl-associated X protein), and TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) staining. The DPOAE values in the diabetic group were found to be significantly lower compared with the other groups at 5,714 Hz and 8,000 Hz (P < .05). No significant difference in otoacoustic emission was detected in the comparison of the RSV doses (P > .05). The histopathologic investigation using caspase-3, Bax, and TUNEL staining showed that the mean rank of the diabetic group was significantly higher compared with the RSV10, RSV20, and control groups (DM > RSV10 > RSV20 > control) (P < .05). These results imply that RSV administration offered statistically significant protection for the cochleas of rats against diabetes. This protective effect improved histologically with higher doses. NA Laryngoscope, 129:E1-E6, 2019.

Does all-day and long-term exposure to radiofrequency radiation emitted from Wi-Fi affect hearing?

ABSTRACTWe investigated the long-term effects of radiofrequency radiation (RFR) emitted from Wi-Fi systems on hearing. Sixteen Wistar albino rats were divided equally into two groups: sham control and exposure groups. The rats in the experimental group were exposed to 2.4 GHz RFR emitted from a Wi-Fi generator for 24 h/day for one year. The same procedure was applied to the rats in the sham group, except that the Wi-Fi generator was turned off. All groups were kept in Faraday cages during the 12 months to eliminate external electromagnetic fields. The distance between the Wi-Fi generator antenna and the exposure cages was 50 cm. Pre-exposure distortion product otoacoustic emissions (DPOAE) of all rats were measured at the beginning, 6th and 12th months of the study. The DPOAE values of the sham, baseline and exposure groups were compared statistically. For the 6000 Hz hearing frequency, the DPOAE values in the exposure group were lower than those in the sham group (p < 0.05). Similarly, the 6000 Hz hearing frequency values obtained at the end of the 12th month were also lower than the baseline and 6-month values in the exposure group (p < 0.05). In contrast, the DPOAE values at the 6th and 12th months of exposure for the 2000 Hz hearing frequency were higher than the baseline value (p < 0.05). These results indicated that 12 months of RFR (24 h/day) at 50 cm from a 2.4 GHz Wi-Fi source can affect hearing. However, further studies are necessary.

Evaluation of the possible protective role of naringenin on gentamicin-induced ototoxicity: A preliminary study

ObjectivesThe purpose of this study is to evaluate the possible protective role of naringenin in gentamicin-induced ototoxicity through an audiological, biochemical and histopathological evaluation. MethodsThis study was conducted on 32 adult male rats that were randomized into 4 groups(control, gentamicin, naringenin + gentamicin, and naringenin). Naringenin was given to the rats via oral gavage in a dose of 50 mg/kg/day during the 14 day study period. Gentamicin was given by the intraperitoneal route in a dose of 120 mg/kg/day. Audiological assessment was performed by the distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) measurements, applied to all rats at the beginning of the study, and also on day 14. Biochemical parameters were calculated on day 14 to evaluate the oxidative and antioxidative status. Their cochleae were removed and examined histopathologically, also on day 14. The cochlea of animals were evaluated with the terminal deoxynucleotidyl transferase-mediated dUTPbiotin nick end labeling (TUNEL) method for apoptosis. ResultsOn days 14, DPOAE values and ABR thresholds were preserved in group 3(naringenin + gentamicin) when compared with group 2(gentamicin)(p < 0.008). The total oxidant status values and oxidative stress index values were significantly higher in group 2(gentamicin) than in other groups (p < 0.008). The total antioxidant status value was significantly higher in group 3(naringenin + gentamicin) and group 4(naringenin) than in group 2(gentamicin)(p < 0.008). The number of TUNEL positive cells in both the organ of Corti and the stria vascularis were found to be statistically lower in group 3(naringenin + gentamicin) than in group 2(gentamicin)(p < 0.05). ConclusionOur study has demonstrated that the ototoxic effect generated by gentamicin could be ameliorated with the concurrent use of naringenin.

Evaluation of ototoxicity of intratympanic administration of Methotrexate in rats

ObjectiveMethotrexate is a dihydrofolate reductase enzyme inhibitor with very high selectivity, and it is an antiproliferative folic acid antagonist used for the treatment of autoimmune diseases. In this study, our objective was to evaluate the effect of intratympanic Methotrexate application in the inner ear. MethodsThis study was planned as an animal study. This study performed in a tertiary referral center. 24 healthy female rats were used in our study. They were separated into three groups. 0.2 cc intratympanic saline was applied to both ears of Group 1. Paracentesis was applied to the tympanic membrane in both ears of Group 2. 0.2 cc intratympanic Methotrexate was applied to both ears of Group 3. At the beginning of the study, Distortion-product otoacoustic emissions (DPOAE) and Auditory brainstem response (ABR) of all rats were measured and then again on the 5th, 10th and 15th day. Histologic examinations of all groups were compared. ResultsThere was not any significant difference between basal DPOAE and ABR measurement values of the groups and the results were measured again on the 5th, 10th and 15th day (p > 0.05). There was no difference between the groups in terms of histology. ConclusionThe intratympanic Methotrexate injection does not have any ototoxic effect on inner ear. We assume that intratympanic Methotrexate could be used safely on inner ear diseases in which steroid treatment is contraindicated or not effective.

Curcumin protects against acoustic trauma in the rat cochlea

ObjectivesIn this study we evaluated the therapeutic utility of curcumin in a rodent model of acoustic trauma using histopathology, immunohistochemical, and distortion product otoacoustic emission (DPOAEs) measurements. Methods28 Wistar albino rats were included in the study and randomly assigned to 4 treatment groups. The first group (group 1) served as the control and was exposed to acoustic trauma alone. Group 2 was the curcumin group. Group 3 was the curcumin plus acoustic trauma group. Group 4 was the saline plus acoustic trauma group. Otoacoustic emission measurements were collected at the end of the experiment and all animals were sacrificed. Cochlea were collected and prepared for TUNEL (TdT-mediated deoxyuridinetriphosphate nick end-labelling) staining assay. ResultsGroup 3 maintained baseline DPOAEs values at 3000 Hz, 4000 Hz and 8000 Hz on the 3rd and 5th day of the experiment. DPOAEs results were correlated with the immunohistochemical and histopathological findings in all groups. In comparison to the histopathologic control group, Group 1 exhibited a statistically significant increase in apoptotic indices in the organ of Corti, inner hair cell, and outer hair cell areas (p < 0.05). Relative to the control group, rats in Group 3 showed little increase in inner hair cell and outer hair cell apoptotic indices. ConclusionsOur results support the conclusion that curcumin may protect the cochlear tissues from acoustic trauma in rats. Curcumin injection prior to or after an acoustic trauma reduces cochlear hair cell damage and may protect against hearing loss.

The protective role of tetramethylpyrazine against cisplatin-induced ototoxicity

ObjectivesThe aim of the present study was to investigate the protective effect of tetramethylpyrazine (TMP) on cisplatin-induced ototoxicity in rats. MethodsForty healthy, female, 24-week-old, Sprague-Dawley rats (n = 40) were randomly assigned to four groups as follows: group one (n = 10) received intraperitoneal (i.p.) physiological saline at daily doses of 3 mg/kg for seven days; group two (n = 10) received a single dose of i.p. 15 mg/kg cisplatin; group three (n = 10) received i.p. 140 mg/kg TMP daily for seven days plus a single dose of i.p. 15 mg/kg cisplatin on the fourth day; group four (n = 10) received i.p. 140 mg/kg TMP daily for seven days. Auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) measurements were obtained from the animals (40 rats, 80 ears) under general anesthesia before and after drug administration. The temporal bulla of animals were bilaterally removed for immunohistopathological examination. ResultsIn group two, DPOAE and ABR values were significantly deteriorated after drug administration, whereas there was no statistically significant difference between the pre- and posttreatment DPOAE and ABR values for all frequencies for groups one, three and four. The mean scores for external ciliated cells (ECCs), stria vascularis (SV) and spiral ganglion (SG) injuries in hematoxylin and eosin (H&E) staining, and also caspase-3 immunoreactivity were significantly higher in group two than in the other groups. ConclusionIn the present study, the protective effect of TMP on cisplatin ototoxicity was demonstrated through studies of electrophysiology and immunohistopathology. Co-administration of TMP may have potential protective effects against cisplatin-induced ototoxicity.

Noise sensitivity and hyperacusis in patients affected by multiple chemical sensitivity.

The aim of this study was to investigate the presence of noise sensitivity and hyperacusis in patients suffering from multiple chemical sensitivity (MCS), a chronic condition characterized by several symptoms following low-level chemical exposure. Moreover, distortion product otoacoustic emissions (DPOAE) were performed to further study cochlear function. A questionnaire-based survey was performed. Eighteen MCS patients, selected with strict diagnostic criteria, and 20 healthy age- and gender-matched subjects filled Weinstein's Noise Sensitivity Questionnaire (WNS) and Khalfa's Hyperacusis Questionnaire (HQ). Results were compared with scores from the quick Environmental Exposure Sensitivity Index (qEESI), a routinarily used questionnaire to screen MCS symptoms, and with DPOAE values. An analysis of variance (ANOVA) was performed between MCS and control subjects scores; moreover, Spearman's rank correlation test was performed between questionnaire results. ANOVA testing on DPOAE values showed any significant difference between groups, while WNS, HQ and qEESI scores were significantly higher in MCS group compared to controls. Correlation analysis showed strong positive correlation between WNS, HQ and qEESI in MCS subjects. For the first time, auditory-related perceptual disorders were studied in MCS. A strong association between WNS, HQ results and MCS symptoms severity has been highlighted. These findings suggest that decreased sound tolerance and noise sensitivity could be considered as possible new aspects of this syndrome, contributing to its peculiar phenotype. Furthermore, as DPOAE values did not differ from healthy subjects, present findings might suggest a 'central' source for such disorders in this group of patients.

Intraperitoneal curcumin and vitamin E combination for the treatment of cisplatin-induced ototoxicity in rats

IntroductionCisplatin ototoxicity is characterized by irreversible, progressive, bilateral sensorineural hearing loss at high frequencies, accompanied by tinnitus. The aim of this study is to demonstrate the protective action of curcumin alone or in combination with vitamin E against cisplatin-induced ototoxicity in animal models. Material and methodsThe study included 42 rats. Experimental animals were randomized into 6 groups. In the first group, intra-peritoneal cisplatin was administered alone. In the second group, intra-peritoneal cisplatin and curcumin were administered together. In the third group, intra-peritoneal cisplatin and vitamin E were administered together. In the fourth group, intra-peritoneal cisplatin was administered together with curcumin in combination with vitamin E. In the fifth group, intra-peritoneal curcumin was administered alone. The sixth group was sacrificed directly without administration of any drugs. A distortion product otoacoustic emission (DPOAE) test was applied to both ears of all experimental animals. Curcumin was administered 1 h before cisplatin treatment continued for three successive days. Vitamin E was administered only as a single dose 30 min prior to cisplatin. All animals were sacrificed following DPOAE testing on the 5th day of cisplatin administration. Histopathological findings included a TUNEL (TdT-mediated deoxyuridine triphosphate nick end-labeling) assay, and the percentage of apoptotic cells was calculated. DPOAE values and the percentage of apoptotic cells were compared before and after treatment and between experimental groups. ResultsIn Group 1, DPOAE values were significantly decreased at all frequencies (3000 Hz, 4000 Hz and 6000 Hz; P < 0.05). In Groups 2, 3, 4 and 5 there was no significant difference between the pre- and post-treatment DPOAE results (p > 0.05). Apoptotic index values were lower in all treatment groups compared to the cisplatin group, however the difference was only statistically significant in group 3 (p = 0.009). ConclusionIn rats, cisplatin ototoxicity can be prevented with curcumin or curcumin-vitamin E combination.