Effect of perinatal and postnatal thiamine deficiency on auditory pathway of the Wistar-Albino rats

Abstract Objective: In this study, we created an animal model to demonstrate the effects of thiamine on the hearing pathways of new-borns during pregnancy and lactation by inducing a dietary thiamine deficiency in the mother. Methods: The study included 16 female Wistar albino rats. The animals were separated into four groups and provided the appropriate amounts of dietary thiamine according to their groups during pre-pregnancy, pregnancy, and lactation periods. Three pups from each mother were included in the study, and 12 pups were selected from each group. On the fortieth day after birth, the auditory pathways of 48 pups in the 4 groups were examined electro physiologically and ultra-structurally. Results: In Group N-N, morphology of hair cells stereocilia degeneration was not obtained in all turns of cochlea. In Group N-T, Inner Hair Cells (IHCs) and Outher Hair Cells (OHCs) stereocilia didn't show degeneration in all turns of cochlea but had rupture inrows of HCs stereocilia. In group T-N IHCs stereocilia less degeneration was observed in all turns of cochlea. OHC stereocilia partial loss was observed only in basal turn of cochlea. In Group T-T IHCs stereocilia was observed less degeneration and rupture in all turns of cochlea. Conclusion: Thiamine is vital for the development of cochlear hair cells during both prenatal and postnatal periods. Even partial deficiency of thiamine causes significant degeneration to the auditory pathway. Level of evidence: The level of evidence of this article is 5. This article is an experimental animal and laboratory study.

Effects of Low Birth Weight Babies on Cochlear Function In Newborns at Dr Soetomo Hospital Surabaya

@#Introduction: The prevalence of hearing loss ranges from 1 to 3 per 1000 live births and 2-4 per 100 high-risk babies as in low birth weight babies. Hearing screening in all newborns has not been fully implemented at Dr. Soetomo Hospital Surabaya so this research is expected to be the basis for hearing screening in all babies born especially low birth weight babies (LBW). The objective of the study was to predict the effect of low birth weight babies on impaired cochlear function in newborns. Methods: Cross-sectional comparative study was conducted from September 2018 to March 2019 in Dr. Soetomo Hospital. The subjects of this study were infants aged 2-28 days old in the nursery. Distortion Product Otoacoustic Emissions (DPOAE) was used to examineselected babies who fulfilled the selection criteria. Results: Twenty babies (≥2500 gram) and 20 babies (<2500 grams) were selected in this study. The proportion of cochlear dysfunction in infants with birth weights <1500 grams and 1500-2500 grams in Dr. Soetomo Hospital Surabaya was 50% and 35.7%. In multivariate analysis birth weight <1500 and birth weight 1500-2499 had a risk respectively 2.06 (95% Confidence Interval 0.08-48.26 P = 0.653) and 1.20 (95% Confidence Interval 0.07-20.34 P = 0.899) respectively. The proportion of cochlear dysfuntion in babies with birth weight ≥2500 grams is the highest which is 65 %. Conclusion: In this study Low Birth Weight Babies have a risk of 35.7 % of impaired cochlear function We would recommend DPOAE as screening method in all babies at Dr. Soetomo Hospital, Surabaya which is continued by second screening examination within one month on high risk babies and failed first test.

The effectiveness of eugenol against cisplatin-induced ototoxicity / A eficácia do eugenol contra a ototoxicidade induzida pela cisplatina

Abstract Introduction: Ototoxicity refers to cellular damage or function impairment developing in the inner ear in association with any therapeutic agent or chemical substance, and still represents the principal side-effect restricting the use of cisplatin. Objective: The aim of this study was to perform a biochemical, functional and histopathological investigation of the potential protective effect of eugenol against cisplatin-induced ototoxicity. Methods: The study was performed with 24 female Sprague Dawley rats. Distortion product otoacoustic emissions tests were performed on all animals, which were randomized into four equal groups. A single intraperitoneal dose of 15 mg/kg cisplatin was administered to cisplatin group, while the eugenol group received 100 mg/kg eugenol intraperitoneal for five consecutive days. 100 mg/kg eugenol was administered to cisplatin + eugenol group for 5 days. On the third day, these rats were received a single dose of 15 mg/kg cisplatin. The control group was given 8 mL/kg/day intraperitoneal saline solution for five days. The distortion product otoacoustic emissions test was repeated 24 h after the final drug administration. All animals were sacrificed, and the cochleas were subsequently used for biochemical and histopathological examinations. Results: Cisplatin caused oxidative stress in the cochlea, impaired the cochlear structure and significantly reduced signal noise ratio levels. Administration of eugenol together with cisplatin reversed these effects and provided functional, biochemical and histopathological protection. Conclusion: The study findings represent the first indication in the literature that eugenol may protect against ototoxicity by raising levels of antioxidant enzymes and lowering those of oxidant parameters.

Resumo Introdução: A ototoxicidade refere-se ao dano celular ou comprometimento da função da orelha interna associado a qualquer agente terapêutico ou substância química e ainda representa o principal efeito colateral que restringe o uso da cisplatina. Objetivo: O objetivo deste estudo foi realizar uma investigação bioquímica, funcional e histopatológica do potencial efeito protetor do eugenol contra a ototoxicidade induzida pela cisplatina. Método: O estudo foi realizado com 24 ratos fêmeas Sprague Dawley. Testes de emissões otoacústicas por produto de distorção foram realizados em todos os animais, os quais foram randomizados em quatro grupos iguais. Uma única dose intraperitoneal de 15 mg/kg de cisplatina foi administrada ao grupo cisplatina, enquanto o grupo eugenol recebeu 100 mg/kg de eugenol intraperitoneal por cinco dias consecutivos. Foram administrados 100 mg/kg de eugenol ao grupo cisplatina + eugenol durante 5 dias. No terceiro dia, estes ratos receberam uma dose única de 15 mg/kg de cisplatina. O grupo controle recebeu 8 mL/kg/dia de solução salina intraperitoneal por cinco dias. O teste de emissões otoacústicas por produto de distorção foi repetido 24 horas após a administração final do medicamento. Todos os animais foram sacrificados e as cócleas foram posteriormente utilizadas para exames bioquímicos e histopatológicos. Resultados: A cisplatina causou estresse oxidativo na cóclea, prejudicou a estrutura coclear e reduziu significativamente os níveis da relação sinal/ruído. A administração de eugenol juntamente com a cisplatina reverteu esses efeitos e forneceu proteção funcional, bioquímica e histopatológica. Conclusão: Os achados do estudo representam a primeira indicação na literatura de que o eugenol pode proteger contra a ototoxicidade, eleva os níveis de enzimas antioxidantes e diminui os níveis dos parâmetros oxidantes.

Protective effect of gallic acid against cisplatin-induced ototoxicity in rats / Efeito protetor do ácido gálico contra a ototoxicidade induzida por cisplatina em ratos

Abstract Introduction: Cisplatin is an antineoplastic agent widely used in the treatment of a variety of cancers. Ototoxicity is one of the main side-effects restricting the use of cisplatin. Objective: The purpose of this study was to investigate the protective efficacy of gallic acid, in biochemical, functional and histopathological terms, against ototoxicity induced by cisplatin. Methods: Twenty-eight female Sprague Dawley rats were included. Rats were randomly assigned into four groups of seven animals each. Cisplatin group received a single intraperitoneal dose of 15 mg/kg cisplatin. Gallic acid group received intraperitoneal gallic acid at 100 mg/kg for five consecutive days. Cisplatin + gallic acid group received intraperitoneal gallic acid at 100 mg/kg for five consecutive days and a single intraperitoneal dose of 15 mg/kg cisplatin at 3rd day. A control group received 1 mL intraperitoneal saline solution for five consecutive days. Prior to drug administration, all rats were exposed to the distortion product otoacoustic emissions test. The test was repeated on the 6th day of the study. All rats were then sacrificed; the cochleas were removed and set aside for biochemical and histopathological analyses. Results: In cisplatin group, Day 6 signal noise ratio values were significantly lower than those of the other groups. Also, malondialdehyde levels in cochlear tissues were significantly higher, superoxide dismutase and glutathione peroxidase activities were significantly lower compared to the control group. Histopathologic evaluation revealed erosion in the stria vascularis, degeneration and edema in the connective tissue layer in endothelial cells, impairment of outer hair cells and a decrease in the number of these calls. In the cisplatin + gallic acid group, this biochemical, histopathological and functional changes were reversed. Conclusion: In the light of our findings, we think that gallic acid may have played a protective role against cisplatin-induced ototoxicity in rats, as indicated by the distortion product otoacoustic emissions test results, biochemical findings and immunohistochemical analyses.

Resumo Introdução: A cisplatina é um agente antineoplásico amplamente usado no tratamento de vários tipos de câncer. A ototoxicidade é um dos principais efeitos colaterais que restringem o uso da cisplatina. Objetivo: O objetivo deste estudo foi investigar a eficácia protetora do ácido gálico, em termos bioquímicos, funcionais e histopatológicos, contra a ototoxicidade induzida por cisplatina. Método: Vinte e oito ratas Sprague-Dawley foram incluídas. As ratas foram distribuídas aleatoriamente em quatro grupos de sete animais cada. O grupo cisplatina recebeu uma única dose intraperitoneal de 15 mg/kg de cisplatina. O grupo ácido gálico recebeu ácido gálico via intraperitoneal a uma dose de 100 mg/kg durante cinco dias consecutivos. O grupo cisplatina + ácido gálico recebeu ácido gálico via intraperitoneal a uma dose de 100 mg/kg durante cinco dias consecutivos e uma única dose intraperitoneal de 15 mg/kg de cisplatina no terceiro dia. O grupo controle recebeu 1 mL de solução salina via intraperitoneal por cinco dias consecutivos. Antes da administração do fármaco, todos os ratos foram expostos ao teste de emissões otoacústicas - produto de distorção. O teste foi repetido no sexto dia do estudo. Todos os ratos foram então sacrificados; as cócleas foram removidas e reservadas para análises bioquímicas e histopatológicas. Resultados: No grupo cisplatina, os valores da relação sinal-ruído do dia 6 foram significativamente mais baixos aos dos outros grupos. Além disso, os níveis de malondialdeído nos tecidos cocleares foram significativamente mais altos, e as atividades de superóxido dismutase e glutatione peroxidase foram significativamente mais baixas em comparação com o grupo controle. A avaliação histopatológica revelou erosão na estria vascular, degeneração e edema na camada de tecido conjuntivo em células endoteliais, comprometimento das células ciliadas externas e diminuição do número dessas células. No grupo cisplatina + ácido gálico, estas alterações bioquímicas, histopatológicas e funcionais foram revertidas. Conclusão: Tendo em vista os nossos achados, consideramos que o ácido gálico pode ter desempenhado um papel protetor contra a ototoxicidade induzida por cisplatina em ratas, conforme indicado pelos resultados do teste emissões otoacústicas - produto de distorção, achados bioquímicos e análises imuno-histoquímicas.

Finding out incidence of deafness among neonates at a tertiary care centre of western Rajasthan, India using otoacoustic emission

Background: Newborn hearing screening is conducted to identify suspected hearing loss and not to confirm the presence/absence of hearing loss or define features of the loss. Speech and hearing are interrelated, i.e., a problem with one could mean a problem with the other as speech and language is acquired normally through auditory system.Methods: A descriptive study conducted in the Department of Paediatrics, Dr. S. N. Medical College, Jodhpur, from June 2016 to December 2017. 5000 neonates were screened using otoacoustic emissions (OAE) in 2 stages at birth during 3rd to 7th day and 15-30 days respectively, followed by BERA at 3 months of age.Results: 1.4 infants per thousand infants had hearing loss. Presence of high-risk factors was seen to be associated be associated with hearing loss more than normal infants on screening with distortion product otoacoustic emissions (DPOAE) tests. However, on testing with BERA no such association was seen.Conclusions: 1.4 per 1000 infants had hearing loss. This study has shown that two stage distortion product otoacoustic emissions (DPOAE) hearing screening followed by british educational research association '(BERA) to confirm the hearing deficit, can be successfully implemented as new born hearing screening method in a hospital set-up, for early detection of hearing impaired, on a large scale, to achieve the high-quality standard of screening programs in a resource limited and developing nation like India.

The Effects of the Treatment with CPAP on Auditory Functions in Patients with Severe OSAHS / 听力学及言语疾病杂志

Objective To investigate the auditory features in patients with severe obstructive sleep apnea hy-popnea syndrome(OSAHS) and the effects of continuous positive airway pressure (CPAP) on auditory functions . Methods Pure tone audiometry thresholds ,auditory brainstem responses (ABR) and distortion product otoacoustic emissions(DPOAE) were performed in three groups with 12 observed objects in each group ,which were the OS-AHS group(before and after treatment of CPAP) ,the simple snoring group and the normal control group .Results In the OSAHS group ,the high frequency auditory thresholds(at 8000 Hz) were greatly higher and the amplitudes of DPOAE reduced ;the detection rates of DPOAE were obviously declined .The peak latencies of Ⅰ ,Ⅲ and Ⅴ , and interpeak latencies of Ⅲ - Ⅴ andⅠ - Ⅴ were longer than those of in the other two groups .The differences were statistically significant(P<0 .05) .The differences of the interpeak latencies of Ⅰ - Ⅲ ,common pure tone au-ditory thresholds (125～4000 Hz) and the thresholds of Ⅴ -wave reaction in the OSAHS group did not change sig-nificantly compared with the other two groups(P>0 .05) .The amplitudes and the detection rates of DPOAEs (0 .5～8 kHz) increased after treatment with CPAP .The differences were statistically significant except the amplitudes of 500 ,750 and 1500 Hz (P<0 .05) .Pure tone audiometry and ABRs did not changed significantly after treatment with CPAP (P> 0 .05) .Conclusion The auditory functions of patients diagnosed with severe OSAHS were im-paired .Treatments with CPAP can partly improve the patients' auditory functions .

Audiological Detection in the Diagnosis of Children with Acute Non-Suppurative Otitis Media (AN-SOM) / 听力学及言语疾病杂志

Objective To study the potential roles of acoustic immittance,distortion product otoacoustic e-mission (DPOAE),and the brainstem response audiometry (ABR)in the diagnosis of children with acute non-sup-purative otitis media (AN-SOM).Methods A retrospective analysis was administered to 182 cases with AN-SOM at the otolaryngology department between March 2014 and March 2015.We compared the results of the acous-tic immitance of 218 symptomatic ears and 146 asymptomatic ears,and also the proportion of DPOAE abnormity and ABR abnormity.We analyzed the specialty of symptomatic ears and asymptomatic ears in 3 terms of audiology test results.Results The proportions of abnormal tympanograms,DPOAE,ABR for symptomatic ear were 64.7%, 72.0%,and 57.8%,which were significantly higher than those of in 41.8%,39.7%,and 35.6% in asymptomatic ear.The difference were statistically significant(P<0.05).A further analysis of audiologic results showed that at least one abnormal result was as high as 196 ears (89.9%)in the asymptomatic ear,90 ears (61.6%)showed no symptoms.The differences were statistically significant(P<0.05).The results of audiology tests showed that tym-panograms in symptomatic ears showed diversity,that were 60.6% for type B or C,35.3% for type A,4.1% for the As.Conclusion The early detections by using acoustic immitance,DPOAE and ABR are very important to the diagnosis of children with acute non-suppurative otitis media.It can improve the sensitivity,and reduce the misdi-agnosis.

Comparison of Transient Evoked Otoacoustic Emissions and Distortion Products Otoacoustic Emissions as the Hearing Screening Methods in the Same Population of Normal Newborns / 听力学及言语疾病杂志

Objective To compare the results of TEOAE and DPOAE in the same population of normal newborns, to provide information on choosing appropriate screening tools.Methods A two-steps protocol was taken with the first screening during the first 48 to 72 hours of birth and rescreened from one to two months old if the newborns failed the first screening.For each step of screening, TEOAE and DPOAE were performed simultaneously using AccuScreen hearing screening instrument (Madsen-GN Otometrics, Taastrup, Denmark).A total of 1 062 normal newborns (F/M=508/554) delivered in Peking Union Medical College Hospital were enrolled in this research for the first screening.Infants who failed either TEOAE or DPOAE screening in the first screening were referred to a second screening.Among them, 135 performed both DPOAE and TEOAE in the second step.The newborns who failed the second screening would receive ABR when they were 3 months old.Results In the first screening,the failure rate for TEOAE was 11.0% (117/1 062) and 13.7% (145/1 062) for DPOAE.In the second screening step, the failure rates were 17.8% (24/135) and 20.7% (28/135) for TEOAE and DPOAE, respectively.Chi-square and Fisher's test showed that the failure rates of DPOAE were significant higher than TEOAE for both steps (P<0.001).The agreements between TEOAE and DPOAE were 96.0% and 95.6% for the first and second steps respectively, and the kappa values were 0.817 and 0.857.As to the average time taken to accomplish the screening for one ear, TEOAE was 24±25 s and DPOAE was 40±34 s during the first screening;in the rescreening, TEOAE was 52±41 s and DPOAE was 73±62 s.Paired-t tests showed that the differences between DPOAE and TEOAE testing time were statistically significant (P=0.000) in both screening steps.Finally, 7 newborns (10 ears) were diagnosed conductive hearing loss(except 1 ear was sensorineural hearing loss).Conclusion As a screening tool, TEOAE got lower refer rates and took less time than DPOAE implicating TEOAE a better screening tool for normal neonates.

Influence of Hormonal Changes on Audiologic Examination in Normal Ovarian Cycle Females: An Analytic Study

Abstract Introduction There is only limited information from previous studies that suggest that auditory function may be influenced by hormones. Recent advances in the field have exposed the potential role of hormones in modulating the auditory system. Objective This study aims to investigate the relationship between menstrual cycle and outer hair cell function with audiological examination. Methods This is an analytic study with a cross-sectional design. The sampling was a systematic random sampling. We found 49 women with normal menstrual cycle and collected their data through interviews, physical examination, and examination of the ear, with otoscopic and other routine otorhinolaryngology examinations. We evaluated Tympanometry, distortion-product otoacoustic emissions (DPOAE), and pure tone audiometry. Results We found the audiometric threshold worse in the follicular phase than other phases at 4000 Hz of the right ear, and in the ovulation was found best than any other phases at 1000 Hz of the left ear with significant difference. We found significant difference of DPOAE between ovulation time and follicular phase at 3000 Hz and 1000 Hz in the left ear and between ovulation and luteal phased at 2000 Hz, 3000 Hz and 5000 Hz in the right ear and at 1000 Hz in the left ear with p< 0.05. Conclusion The result of this study showed that only a small part of audiometry threshold had a significant difference between each menstrual phase. In other words, we found no correlation between menstrual and audiometry threshold. Nonetheless, there is a correlation between menstrual cycle phase and DPOAE amplitude.

Pure tone threshoIds and Otoacoustic Emissions in PCI Patients without Hearing Loss CompIaints / 听力学及言语疾病杂志

Objective To study the audiometry and otoacoustic emissions in patients with posterior circulation ischemia(PCI) .Methods Forty patients treated by neurologists were selected as the experimental group who re_ceived pure tone audiometry ,tympanometry ,otoacoustic emissions (OAE) and distortion products otoacoustic emis_sions (DPOAE) examinations .Thirty healthy objects were chosen as the control group .The data from the PCI groups and the control group were compared using the SPSS 14 .0 software .ResuIts The difference in pure tone thresholds across 125 to 8 000 Hz between the PCI group and the control group was not statistically significant (P>0 .05) .In the PCI patients ,the prevalence of TEOAE was only 47 .5% ,significantly different from that of in the control group .The prevalence of DPOAE at 0 .5~8 kHz were between 57 .9% ~77 .6% in PCI patients ,and the amplitudes of DPOAE were reduced significantly (P<0 .05) .ConcIusion Cochlear damages can occur to patients with PCI ,especially in the high frequency range .These results suggest that OAE can be used as an important diag_nostic test for patients with PCI ,and might be helpful for the location diagnosis of PCI .

Optimization of the Frequency Ratios for DPOAEs and Its Application in the Measurement of Normal and Hearing Loss Ears / 听力学及言语疾病杂志

Objective To optimize the f2/f1 frequency ratios for DPOAEs and to evaluate the effects in the measurement of normal and hearing loss ears .Methods Seven of 18 guinea pigs were randomly selected and DPOAE measurements were performed ,using the L2 stimulus levels of 25 ,40 and 60 dB SPL ,L1 = 0 .46 L2 +41 dB SPL .The stimulus frequency f2 ranged from 1 to 16 kHz ,and the f2/f1 ratio ranged from 1 .1 to 1 .5 .The maxi-mum DPOAEs (Ldp ) were determined and the corresponding f2/f1 ratios were used as the parameters for DPOAE measurement .The inner ears of all the 18 animals were operated unilaterally .One week later ,They were divided in-to 2 groups(A and B) and DPOAE measurements were performed with the optimal f2/f1 ratio in group A and with the fixed f2/f1 ratio in group B separately .Results When f2 ranged from 1~2 kHz ,the optimal f2/f1 ratio rose from 1 .25 to 1 .44 ;then it reduced to 1 .17 when f2 was 8 kHz .When f2 ranged from 8~16 kHz ,the optimal f2/f1 ratio rose slightly to 1 .24 .Compared with the fixed f2/f1 ratio in group B ,using the optimal f2/f1 ratio in group A could determine more precise DPOAEs in the operated ears ,especially in the f2 range from 1~4 kHz .Conclusion Using optimal f2/f1 ratios can promote the sensibility for the DPOAE measurements .

The Study on the Mechanisms of Early sensorineural Hearing Loss in Diabetic Rats / 听力学及言语疾病杂志

Objective To investigate the mechanisms of early sensorineural hearing loss of diabetic rats. Methods The diabetic model for rats was established. Every rat was checked with ABR and DPOAE before and af-ter treatment . After 14 days , the blood glucose, blood fat, SOD, GSH-Px and MDA were measured. Results For the model group, the rats" blood glucose and fat increased while the GSH-Px was reduced more than the con-trol group. The response amplitudes of DPOAE decreased at 4 000 Hz and 8 000 Hz(P<0. 05). Conclusion The damage to the hair cells caused by the affected metabolism is considered as the culprit of the sensorineural hearing loss and the changes of DPOAE took place earlier than that of ABR, thus becoming useful in detecting early hearing loss of the diabetic patients.

The Feasibility of Using Automated Distortion Product Otoacoustic Emission (DPOAE) as a Screening Auditory Function Test of Workers in a Noisy Environment / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Automated DPOAE (Distortion product otoacoustic emission) was tested on workers exposed to a noisy environmnent to determine its feasibility as a screening test for noise-induced hearing loss. SUBJECTS AND METHOD: Sensitivity and specificity were analyzed for in both automated DPOAE and Pure tone audiometry conducted on 300 subjects working in a noisy environment. Of these subjects, a subgroup of 40 workers who were available for a follow-up study underwent the same experiment again a year later, and the results were compared with the first one. RESULTS: In terms of the frequency of automated DPOAE, it was noted that it showed 91% sensitivity with a 9% false negative rate. The pass rate according to the period of service indicated statistical significance, although the results of a 1 year follow-up experiment did not indicate statistical significance. CONCLUSION: The automated DPOAE seems feasible to use as a screening test when frequency and adjusted reference criteria are considered.

The Effect of Contralateral Acoustic Stimulation on the Latency of Distortion Product Otoacoustic Emissions / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The auditory efferent system -Medial olivocochlear bundle (MOCB)-controls the sensitivity and frequency selectivity of the cochlea and maintains the cochlea for optimal acoustic signaling. Contralateral acoustic sound stimulates the MOCB and has inhibitory effects on the sound evoked amplitude response of the cochlea. There are only a few reports on the latency response of contralateral acoustic stimulation (CAS) on distortion product otoacoustic emission (DPOAE), and it has no consistent conclusion. The purpose of this study was to evaluate whether changing the latency of DPOAE by CAS could be a stable method for monitoring the function of MOCB. SUBJECTS AND METHOD: The change in the latencies of DPOAE after CAS were monitored in 24 normal hearing ears with f2 sweep paradigm. The CAS level was divided into two groups, one was under 65 dB SPL and other was over 65 dB SPL. RESULTS: As f2 frequency changed from 1 kHz to 2 kHz, the latency of DPOAE was shortened from 11.82 +/- 1.87 ms to 7.29 +/- 0.86 ms in low stimulation level (50 dB SPL) and from 10.70 +/- 2.65 ms to 6.16 +/- 1.59 ms in high stimulation level (75 dB SPL) There were no significant shortening on the latency of DPOAE after CAS in low stimulation level group. But in higher stimulation level group (75 dB SPL), DPOAE latency changed from 10.70 +/- 2.65 ms to 10.12 +/- 1.95 ms (CAS level: 35 dB SL) and to 9.76 +/- 2.97 ms (CAS level: 50 dB SL) in 1 kHz, from 6.16 +/- 1.59 ms to 5.96 +/- 1.49 ms (CAS level: 35 dB SL) and to 5.83 +/- 1.28 ms (CAS level: 50 dB SL) in 2 kHz. CONCLUSION: Changes in the latency of DPOAE after CAS is not a stable monitoring tool for the function of MOCB.

The Predictive Study for Hearing Loss using Distortion Product Otoacoustic Emission in Mild Noise-Induced Hearing Loss / 대한산업의학회지

OBJECTIVE: The aim of this study was to predetermine the discrimination standard point of distortion product otoacoustic emission(DPOAE) amplitudes, which discriminates the degree of the mild noise-induced hearing loss, and to estimate the accuracy and predictability of the discrimination standard point of DPOAE amplitudes. Therefore we were able to determine the usability of the DPOAE test in screening exam for mild noise-induced hearing loss. METHODS: This study was analyzed 50 high frequency-impaired ears(from 25dB HL to 40dB HL at 4000Hz for which the response of DPOAE was not disappeared) and 81 normal ears through the correlation test between the amplitudes of DPOAE test and the threshold of the pure-tone audiometry test. RESULT: The discrimination between >or=25dB and

Distortion Product and Spontaneous Otoacoustic Emissions in Normal Neonates / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Distortion product otoacoustic emission (DPOAE) offers an alternative to transiently evoked OAE as a neonatal hearing screening, and may provide frequency specific information of the cochlea. The purpose of this study is to establish the relevant characteristics of spontaneous OAE (SOAE) and DPOAE of neonates and their efficacy as a neonatal screening method for hearing loss. MATERIALS AND METHODS: From July to September 1999, 72 healthy newborns (144 ear) were included in this study and test was performed within 3 days after birth at nursery. DP audiogram, input/output (I/O) curve at 3 kHz, and SOAE were recorded. RESULTS: The DP audiogram had characteristics with two broad peaks of amplitude at Fe (geometric mean of two primaries) frequencies of 3 kHz and 6 kHz. From the Fe near 3 and 6 kHz, DPOAE was found over 95% of 144 ears. Median threshold of 3 kHz I/O curve was 40 dB. The threshold in 3 kHz could be obtained even in 7 ears that had failed to pass DP audiogram. The thresholds of the ears that failed in DP audiogram were not statistically different from those that passed the test, The amplitude in DP audiogram was not correlated with the threshold in 3 kHz I/O curve. The positive rate for SOAE was 45% (39% in male, 53% in female, 51% in right ear, 38% in left ear, respectively), All the SOAE positive cases passed DP audiogram test. CONCLUSIONS: DPOAE has a potential for neonatal screening test for hearing loss. Near 3 kHz and 6 kHz, DPOAE were highly positive, and these frequencies can be used in screening test. The duration of a diagnostic test would be shorter by excluding certain frequencies. Using the 3 kHz I/O curve in addition to DP audiogram may increase the validity and the e6cacy of the test. SOAF has limitations as a single modality of neonatal screening test for hearing loss.

Change of the DPOAE on Contralateral Ear after Exposure of the Drilling Noise / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Drill-generated noise during chronic ear surgery, as well as surgical trauma, has been incriminated as a cause of sensorineural hearing loss in the operated ear. The contralateral ear, on the other hand, is subject to drill noise but is spared the surgical trauma. Using the distortion product otoacoustic emission recording, this study is aimed to evaluate changes in micromechanical cochlear properties which could occur in the contralateral ear following an ear surgery. MATERIALS AND METHODS: Twenty-seven patients undergoing mastoidectomy procedures were tested both preoperatively and postoperatively using pure tone audiometry, distorsion product otoacoustic emission. Surgical drilling duration was recorded. These patients had no otological history and showed no abnormalities on the physical examination of the contralateral ear. For all frequencies (1-6 kHz), amplitude were measured and analyzed. RESULTS: 1) Pure tone audiometry average was not significantly changed on the preoperative and postoperative day. 2) Average amplitude of DPOAE was significantly lower on the first postoperative day than on the preoperative day. 3) Average amplitude of' DPOAE was recovered on the seventh postoperative day. 4) Duration of drilling affected DPOAE results. CONCLUSION: The drill noise conducted to the nonoperated ear by vibrations of the intact skull exposure results in dysfunction of the outer hair cells, which produce a temporary hearing loss.

Study of the Antagonist Effects of Sodium Salicylate on the Cisplatin Induced Hearing Impairment in Guinea Pigs / 听力学及言语疾病杂志

Objective To investigate the antagonist effects of sodium salicylate(NaSA) on the cisplatin(CDDP) induced hearing impairment in guinea pigs.Methods 60 guinea pigs were randomly divided into four groups: ①CDDP +NaSA(50 mg/kg) group,②CDDP +NaSA(100 mg/kg) group,③CDDP +NaSA(150 mg/kg) group and ④CDDP +NS(normal saline) control group.Auditory brainstem response(ABR) and distortion product otoacoustic emission(DPOAE) were used to evaluate their effects on hearing threshold and DPOAE amplitudes.Results The ABR responses of groupsⅠ,Ⅱ and Ⅲ were significantly lower than in the control group(P0.05).The ABR responses for group Ⅰ were significantly higher than group Ⅲ(P

DPOAE in Acoustic Neuroma / 대한이비인후과학회지

BACKGROUND: Evoked otoacoustic emissions (OAEs) are assumed to reflect healthy outer hair cell function. It is possible that these objective tests can provide some insight into the fundamental basis of the hearing loss exhibited by patients with acoustic neuromas. The primary aim of the present study was to examine the effects of acoustic neuromas on the amplitudes of evoked OAEs and to compare these findings with tumor-induced hearing levels. MATERIALS AND METHODS: The amplitude and growth functions of distortion product otoacoustic emission (DPOAE) at 2f1-f2, elicited by two primary tones f1 and f2 with a constant frequency ratio f2/f1=1.22 and varing geometric mean values 0.5, 1, 2, 4, and 8 kHz, were measured for 13 patients with radiologically proven acoustic neuroma. RESULTS: After comparing audiograms and DP-gram, we found four patients with neural hearing loss, seven patients with sensory (cochlear) hearing loss, and two patients with sensorineural (mixed) hearing loss. There was a strong correlation between the results of DPOAE and the tumor location or duration of symptom, whereas there was no correlation between tumor size and cochlear function. CONCLUSION: DPOAEs can identify preoperatively the sensory (cochlear) components of hearing loss induced by an acoustic neuroma. These emissions are also useful with a battery of retrocochlear screen tests, but they could not be relied on solely to rule out central hearing disorders.

Factors Affecting Distortion Product Otoacoustic Emisson in Newb orn Hearing Screening / 听力学及言语疾病杂志

Objective To seek the factors affecting distortion product otoac oustic emisson in newborn hearing screening. Methods All newborns in our hospital received hearing sc reening by DPOAE and wer e investigated for the factors such as: birth history, pregnancy history, family history, the social position of the family. All data were analysed by SPSS. Results 82.8%(3 242/3 944) newborns passed the hearing sc reening. Pass rates were h igher in right ears, female baby, monocyesis, normal or high birth weight and fo rceps delivery. The Results of the first hearing screening were correlated with birth weight,sex and fetus number by logistic regression. Conclusion The factors suc h as sex, ways of labor, fetus number, fetus age, and birth weight can affect t he results of first hearing screening significantly.