Musical Mistuning Perception and Appraisal in Cochlear Implant Recipients.

OBJECTIVE: Music is a very crucial art form that can evoke emotions, and the harmonious presence of the human voice in music is an impactful part of this process. As a result, vocals have had some significant effects on contemporary music. The mechanism behind the cochlear implant (CI) recipients perceiving different aspects of music is clear; however, how well they perceive vocal tuning within music it is not well known. Hence, this study evaluated the mistuning perception of CI recipients and compared their performance with normal-hearing (NH) listeners. STUDY DESIGN, SETTING, AND PATIENTS: A total of 16 CI users (7 cisgender men, 9 cisgender women) and 16 sex-matched NH controls with an average age of 30.2 (±10.9; range, 19-53) years and 23.5 (±6.1; range, 20-37) years, respectively, were enrolled in this study. We evaluated the mistuning ability using the mistuning perception test (MPT) and assessed self-perceived music perception and engagement using the music-related quality-of-life questionnaire. Test performance was measured and reported on the item-response theory metric with a z score ranging from -4 to +4. RESULTS: A significant difference in the MPT scores was found between NH and CI recipients, whereas a significant correlation was noted between the music-related quality-of-life questionnaire-frequency subscale and MPT scores. No significant correlations were found between age, CI age, and CI usage duration and MPT performance. CONCLUSIONS: This study revealed that musical mistuning perception is a limitation for CI recipients, similar to previously evaluated aspects of music perception. Hence, it is important to consider this aspect in the assessment of music perception, enjoyment, and music-based auditory interventions in CI recipients, as vocals are paramount in music perception and recreation. The MPT is a convenient and accessible tool for mistuning assessment in CI and hearing-aid users.

The Effect of Nonlinear Frequency Compression on Acoustic Change Complex Responses in High-Frequency Dead-Regioned Hearing Loss.

PURPOSE: The study is concern with the distinguishing of the stimuli containing high frequency information with the frequency compression feature at the cortical level using the acoustic change complex (ACC) and the comparison of such with the ACC answers of individuals with normal hearing. RESEARCH DESIGN: This is a case-control study. STUDY SAMPLE: Thirty adults (21 males and nine females) with normal hearing, ranging in age between 16 and 63 years (mean: 36.7 ± 12.9 years) and 20 adults (16 males and four females) with hearing loss ranging in age between 16 and 70 years (mean:49.0 ± 19.8 years) have been included in this study. DATA COLLECTION AND ANALYSIS: A total of 1,000 ms long stimulus containing 500 and 4,000 Hz tonal stimuli was used for ACC recording. The start frequency (SF) and compression ratio (CR) parameters of the hearing aids were programmed according to the default settings (SFd, CRd) in the device software, the optimal setting (SFo, CRo), and the extra compression (SFe, CRe) requirements and ACC has been recorded for each condition. Evaluation has been performed according to P1-N1-P2 wave complex and ACC complex wave latencies. Independent samples t-test was used to test the significance of the differences between the groups. RESULTS: In all individuals ACC has been observed. There was a significant difference between the wave latencies in normal hearing- and hearing-impaired groups. All wave latency averages of the individuals with hearing impairment were longer than the individuals with normal hearing. There were statistically significant differences between SFd-SFo, SFd-SFe, and SFo-SFe parameters. But there was no difference between CRd, CRo, and CRe in terms of CRs. CONCLUSION: In order to discriminate high frequency information at the cortical level we should not rely on default settings of the SF and CR of the hearing aids. Optimal bandwidth must be adjusted without performing insufficient compression or over-compression. ACC can be used besides the real ear measurement for hearing aid fitting.

Does intratympanic xylitol administration have ototoxic effects in a mouse ear model?

OBJECTIVE: To research the ototoxicity of xylitol after intratympanic injection in mice ear model. METHODS: 24 female mice Balb/c mice (48 ears) included in the study. The mice were divided into 4 groups as 6 mice were found (12 ears) in each group. Solutions of 0.9% NaCl solution (Group A), 155 mg/ml (Group B), 310 mg/ml (Group C) and 620 mg/ml (Group D) xylitol, were applied into the middle ear cavity. Microscopic ear examination and auditory brainstem response test were done for each mouse before application of xylitol and on the 1st, 3rd and 10th day of injection. RESULTS: There are some statistically significant alterations found in the threshold values at 8000, 12000, 16000, 24000 Hz frequencies when each group were compared in itself on day 0, 1,3 and 10, which were independent from the increasing dosage. CONCLUSION: According to our findings intratympanic xylitol injection does not have any ototoxic effect in the inner ear. To evaluate the effects of xylitol more clinical studies are need to carried out.

Oxytocin as a protective agent in cisplatin-induced ototoxicity.

PURPOSE: Cisplatin is a potent chemotherapeutic drug with serious side effects such as ototoxicity which is characterized by irreversible, bilateral, progressive sensorineural hearing loss. Oxytocin, which is a well-known hormone secreting during pregnancy, has antioxidant and antiinflammatory effect. Our study aims to test and compare the effect of intratympanic (IT) and intraperitoneal (IP) oxytocin on cisplatin ototoxicity with DPOAE. METHODS: A total of 24 Wistar albino rats were randomly divided into four groups: Group 1 received 0.1-0.3 ml IT saline + IP saline solutions for 4 days (n = 6), Group 2 received cumulative dose of 20 mg/kg IP cisplatin divided into two equal doses in first and second days of experiment + 0.1-0.3 ml IT saline for 4 days, Group 3 received same dose of cisplatin as Group 2 + 0.1-0.3 ml IT oxytocin for 4 days, and Group 4 received same dose of cisplatin as Groups 2 and 3 + IP oxytocin with dose of 1 mg/kg. DPOAE was performed prior to procedure and at the end of the experiment on day 5. RESULTS: Group 2 showed severe ototoxic effect of cisplatin according to DPOAE result (p < 0.05). When compared with Group 2, DPOAE amplitude reductions were smaller in Group 3 (3.2, 3.8, 4.5, 6.3 and 7.6 kHz) (p < 0.05) and Group 4 which is statistically significant in 5.4, 6.3 and 7.6 kHz (p < 0.05). When Group 3 and Group 4 were compared, reductions were smaller in 2.7 and 3.2 kHz in Group 3 (p < 0.05). CONCLUSION: In this study, we showed the protective effect of IT and IP oxytocin on cisplatin ototoxicity. We suggest oxytocin in cisplatin ototoxicity, especially via IT route even with high-dose cisplatin.

Effect of Transtympanic Injection of Melatonin on Cisplatin-Induced Ototoxicity.

OBJECTIVE: Cisplatin is a chemotherapeutic agent that is widely used in cancer treatment. Numerous side effects have been detected, one of which is ototoxicity. Melatonin, a product of the pineal gland, has a neuroendocrinoimmunological role in vertebrates. In the present study, we investigated the effects of melatonin on cisplatin-induced ototoxicity. MATERIALS AND METHODS: Twenty-four Wistar albino rats were divided into three groups. Group 1 was administered both intraperitoneal and transtympanic saline; Group 2, 12 mg/kg of intraperitoneal single-dose cisplatin and transtympanic saline; and Group 3, 12 mg/kg of intraperitoneal single-dose cisplatin and 0.1 mg/mL of transtympanic melatonin for 5 days. Before and after the procedure, distortion product otoacoustic emissions and auditory brainstem responses of all the rats were measured. At the end of the procedure, the cochleas of the rats were investigated at the microscopic level. RESULTS: Group 3 had lesser threshold shift in otoacoustic emissions and auditory brainstem responses at all frequencies than Group 2 (p<0.005). The difference was not significant between Group 1 and Group 3. On the microscopic level, more epithelial loss and less TNF staining were detected in Group 2 than in Group 3. CONCLUSION: As an antioxidant and immune modulator, melatonin is effective against cisplatin ototoxicity. Both hearing thresholds and tissue investigations supported this conclusion. Melatonin can also be used to treat cisplatin ototoxicity using transtympanic local application in lower doses.

Protective role of resveratrol against cisplatin induced ototoxicity in guinea pigs.

OBJECTIVE: The aim of this study was to evaluate the effectiveness of systemic administration of resveratrol against cisplatin-induced ototoxicity in guinea pigs. MATERIALS AND METHODS: Healthy guinea pigs (n=24) were randomly divided into four groups. Group 1 (n=6) received resveratrol+cisplatin, group 2 (n=6) received 4% ethanol+cisplatin, group 3 (n=6) received cisplatin, and group 4 (n=6) received saline. Cisplatin was administered at a dose of 10mg/kg/day on days 14 and 15 of the study. Resveratrol (10mg/kg/day), 4% ethanol, and saline were administered throughout the study. Baseline auditory brainstem responses (ABR) (4 kHz, 8 kHz, and click stimulus) were determined for all groups. ABR was repeated 72 h after the last dose of cisplatin in order to record the threshold shifts. The ABR threshold shifts for the click stimulus, 4-kHz- and 8-kHz-frequency stimuli were compared after drug administration. After follow-up ABRs the animals sacrificed under deep sedation and their cochleae were removed. Left cochleae were immediately harvested for measurement of level of reactive oxygen species (ROS). Right cochleae were prepared for histological changes which were observed by scanning electron microscopy (SEM). RESULTS: For the all stimulus, there was a significant threshold difference among the groups (p<0.01). Group 3 had a significantly higher threshold shift at all stimuli when compared with groups 1 and 4. There was no significant threshold shifts in all stimuli between groups 2 and 3. The resveratrol-treated group 1 showed preservation of threshold in ABR (p ≤ 0.05). SEM showed that inner and outer hair cells were preserved in the group 1. Level of reactive oxygen species (ROS) were significantly higher in groups 2 and 3 compared with groups 1 and 4 (p ≤ 0.05). CONCLUSION: These results indicated that systemic administration of resveratrol afforded statistically significant protection to the cochlea of guinea pigs from cisplatin toxicity. Experimental dose of resveratrol injections may have a protective effect against cisplatin ototoxicity in guinea pigs.