Distribution characteristics of normal pure-tone thresholds

Objective: This study examined the statistical properties of normal air-conduction thresholds obtained with automated and manual audiometry to test the hypothesis that thresholds are normally distributed and to examine the distributions for evidence of bias in manual testing. Design: Four databases were mined for normal thresholds. One contained audiograms obtained with an automated method. The other three were obtained with manual audiometry. Frequency distributions were examined for four test frequencies (250, 500, 1000, and 2000 Hz). Study sample: The analysis is based on 317 569 threshold determinations of 80 547 subjects from four clinical databases. Results: Frequency distributions of thresholds obtained with automated audiometry are normal in form. Corrected for age, the mean thresholds are within 1.5 dB of reference equivalent threshold sound pressure levels. Frequency distributions of thresholds obtained by manual audiometry are shifted toward higher thresholds. Two of the three datasets obtained by manual audiometry are positively skewed. Conclusions: The positive shift and skew of the manual audiometry data may result from tester bias. The striking scarcity of thresholds below 0 dB HL suggests that audiologists place less importance on identifying low thresholds than they do for higher-level thresholds. We refer to this as the Good enough bias and suggest that it may be responsible for differences in distributions of thresholds obtained by automated and manual audiometry.     

Concurrent effect of noise exposure and smoking on extended high-frequency pure-tone thresholds

Objective: Concurrent effect of noise and smoking on hearing loss is a recent concern. In this study, the concurrent effect of noise and smoking on hearing loss in conventional frequencies and frequencies higher than 8 kHz was assessed. Design: This was a cross-sectional study on workers exposed to noise who were divided into two groups: smokers and non-smokers. Hearing thresholds were assessed by conventional audiometry, and HFA. Data were analysed using non-parametric tests and Student's t-test. Study sample: There were 212 workers. Results: Ninety-seven subjects were smokers and 115 individuals were non-smokers. All subjects were exposed to 92.1 ± 2.4 dBA (Leq8h). The highest threshold in conventional and high-frequency audiometry was observed at 6 kHz and 16 kHz, respectively. Hearing threshold at frequencies above 1 kHz was significantly higher in the smokers than non-smokers. There was no correlation between hearing thresholds and pack-years of smoking. Conclusions: Concurrent exposure to noise and smoking may be associated with more hearing loss than exposure to noise alone in the conventional and high frequencies. However, other differences between smokers and non-smokers may explain these differences as well.     

Racial and gender effects on pure-tone thresholds and distortion-product otoacoustic emissions (DPOAEs) in normal-hearing young adults

This study examined racial and gender effects on behavioral thresholds and distortion-product otoacoustic emissions (DPOAEs) in the same subjects. Pure-tone behavioral thresholds and DPOAEs were measured in 60 young normal-hearing adult subjects (20 Caucasian, 20 Asian, 20 African-American, with ten females and ten males in each group). Behavioral thresholds were measured from 1000 through 16 000 Hz using Békèsy tracking. A DPOAE frequency sweep was measured with primary stimulus levels of L₁/L₂=60/45 dB SPL, and an f₂/f₁ of 1.2 at discrete f₂ frequencies between 2000 through 12 000 Hz for each subject. Significant racial and gender differences in behavioral thresholds were found at 14 000 and 16 000 Hz, with the African Americans and females having the best hearing sensitivity. Based on the current results, similar findings for DPOAE frequency sweeps can be expected amongst different racial groups given that no significant differences were identified between the groups. To further define the effects of race and gender on auditory measures, future studies should include larger numbers of subjects, measurement of body size and middle ear reflectance, and examine emission generators.     

Incidence of tinnitus in mp3 player users

Exposure to loud noise is one of the main causes of tinnitus.AimTo analyze the incidence of tinnitus in mp3 player users and non-users.Material and methodOne hundred subjects aged from 15 to 30 years were enrolled, 54 of them were regular mp3 player users and 46 were not. Patients with continuous tinnitus for at least 6 months completed the Tinnitus Handicap Inventory (THI) and were tested with high frequency audiometry and transient-evoked otoacoustic emissions (TAOE).Study designA cross-sectional cohort study.ResultsThe incidence of tinnitus in non-users was about 8%; in mp3 player users it was about 28 %, a statistically significant difference. Hearing thresholds at 8kHz were significantly higher in tinnitus patients that used mp3 portable players. TAOE were reduced at 2 kHz in the users group. No statistically significant difference was found in the THI scores between the two groups.ConclusionTinnitus was more frequent in teenagers and young adults who regularly listen to mp3 music in players. Moreover, the incidence of tinnitus among mp3 player users was associated with higher hearing thresholds at 8 kHz and lower TOAE at 2 kHz. Clinicaltrials.gov registration number: NCT 01187251     

Comparison of characteristics observed in tinnitus patients with unilateral vs bilateral symptoms,with both normal hearing threshold and distortion-product otoacoustic emissions

Conclusion: Tinnitus characteristics in normal-hearing patients differ between the groups with unilateral and bilateral complaints.

Objectives: The study was to determine the differences between tinnitus characteristics observed in patients with unilateral vs bilateral symptoms and normal hearing threshold, as well as normal results of distortion-product otoacoustic emissions (DPOAEs).

Method: The patients answered questions concerning tinnitus duration, laterality, character, accompanying symptoms, and circumstances of onset. The results of tympanometry, auditory brainstem responses, tinnitus likeness spectrum, minimum masking level (MML), and uncomfortable loudness level were evaluated. Records of 380 tinnitus sufferers were examined. Patients with abnormal audiograms and/or DPOAEs were excluded. The remaining 66 participants were divided into groups with unilateral and bilateral tinnitus.

Results: Unilateral tinnitus in normal-hearing patients was diagnosed twice more frequently than bilateral. Tinnitus pitch was higher in the group with bilateral tinnitus (p?p?p?p?p?相似文献   

Otoacoustic emissions: assessment of hearing after tympanostomy tube insertion

This study evaluates the use of transient evoked otoacoustic emissions as an alternative to pure tone audiometry for the assesment of hearing after tympanostomy tube insertion. Otoacoustic emissions and pure tone audiometry were carried out in 32 patients in whom tympanostomy tubes had been inserted. Otoacoustic emissions were detected in 78% of patients, whereas pure tone audiometry testing was only possible in 59%. Of 13 children who were 3 years of age or under, otoacoustic emissions could be measured in 62%, compared to pure tone audiometry which was only possible in 8%. Otoacoustic emission testing took on average 3 min, which was less than half the time for pure tone audiometry testing which took 7 min.     

畸变产物耳声发射检测职业性听力损伤的可行性研究

目的 探索畸变产物耳声发射（DPOAE）检测、评估和诊断职业性听力损伤的可行性和临床应用价值。方法 选36例（72耳）噪声暴露青年工人作为实验组，11例（22耳）正常青年人作为对照组，进行纯音听阈和DPOAE幅值、值嗓比和引出率测试。结果 实验组纯音听阈测值在全部频率点均明显提高，与对照组比较有显著性差异（P〈0．05或P〈0．01）。实验组DPOAE幅值和值嗓比在全部频率点均明显下降，与对照组比较有显著性差异（P〈0．01）。实验组DPOAE总引出率下降，与对照组比较有显著性差异（P〈0．01）。f0为1．4、8kHz时，DPOAE频点引出率无明显下降（P〉0．05），而其他频点均明显下降，与对照组比较有显著性差异（P〈0．05或P〈0．01）。结论 用DPOAE测试法检测、评估和诊断职业性听力损伤是可行的，有临床应用价值。其最佳的测试指标为DPOAE幅值、信噪比和总引出率。     

机械纺织工人畸变产物耳声发射的临床研究

目的研究畸变产物耳声发射(distortion product otoacoustic emissions,DPOAE)在监测和早期发现噪声性聋(noise induced hearingloss,NIHL)方面的应用价值。方法检测160名(285耳)机械纺织工人(其中噪声性聋组125例224耳,有噪声接触史但纯音听阈正常者为对照组,共35例61耳)和75名听力正常人(正常对照组)的鼓室导抗图、镫骨肌反射、纯音听阈及DPOAE,比较三组的DPOAE幅值和引出率。结果①噪声性聋组DPOAE幅值及引出率均较正常对照组明显下降(P<0.05);②对照组与正常对照组比较,对照组的DPOAE幅值在4kHz处、引出率在3~6kHz处明显下降(P<0.05);③随着接触噪声工龄的延长,DPOAE引出率逐渐下降(P<0.05)。结论DPOAE可以客观地监测和早期发现噪声性聋,较纯音测听更有意义。     

A longitudinal study of changes in evoked otoacoustic emissions and pure-tone thresholds as measured in a hearing conservation program

Non-linear transient-evoked otoacoustic emissions (TEOAEs) at 74 dB pSPL, distortion-product otoacoustic emissions (DPOAEs) at 65/45 dB SPL and pure-tone audiometry were used to detect noise-induced, inner ear changes in a longitudinal study. Repeated-measures ANOVAs were made on the Noise (n=69) and Quiet (n=42) groups. The Noise group's hearing thresholds increased by 1.2 dB and DPOAE amplitude decreased by ?0.9 dB. For both groups, TEOAE amplitude decreased by approximately ?0.6 dB. Eight of 12 ears with permanent threshold shift (PTS) and 10 of 13 ears with temporary threshold shift (TTS) showed TEOAE decrements or low baseline TEOAE amplitudes. Fewer TTS and PTS ears also showed DPOAE decrements, and there was never a DPOAE decrement without a corresponding TEOAE decrement or low TEOAE baseline. Some TTS ears showed permanent emission decrements. Although otoacoustic emissions show promise in detecting noise-induced inner ear changes, it is premature to use them in hearing conservation programs.     

Analysis of otoacoustic emissions in neonates at term and preterm

The transient evoked otoacoustic emissions (TEOAEs) have been widely used in neonatal hearing screening.ObjectiveTo compare the TEOAEs in newborns at term and preterm vis-à-vis the following variables: ear side, gender, frequency spectrum and gestational age.MethodBy means of a cross-sectional cohort of 66 newborns up to the 28^th day of life (41 newborns at term and 25 premature babies), we recorded TEOAEs. All the individuals did not have risk indicators for hearing loss.ResultsThere was a signal/noise ratio improvement with frequency increase. No differences were observed between genders and between the ears, but there were differences among the children born at term and preterm in the frequency bands at 3 kHz and 4 kHz.ConclusionThe TEOAEs test is important for assessing the peripheral auditory system of newborns at term and preterm, making it possible to have responses regardless of gender and gestational age.     

对侧刺激声影响畸变产物耳声发射临床意义的探讨

观察白噪声对畸变产物耳声发射输入输出函数曲线影响，探讨其临床价值。方法：检测临床患者６１例，包括单纯性耳鸣不伴有听力下降患者３２例；以低频听力下降为主的耳聋患者２７例；蜗后病变２例。     

畸变产物耳声发射与纯音听阈间测试频率的相关性研究

目的探讨畸变产物耳声发射(DPOAE)测值与纯音听阈值之间的相关性，阐明DPOAE测试频率(f0)与纯音听阈测试频率之间的对应关系。方法选正常听力人20倒(40耳)，蜗性聋病人100例(179耳)进行纯音听阈和DPOAE测试。用相关分析的统计方法计算出DPOAE测值与纯音听阈值之间的相关系数。结果DPOAE测值与纯音听阈值之间有负相关关系。f0为0．5、0．75、1．0．1．5、2．0、3．0、4．0、6．0、8．0kHz时的DPOAE测值与测试频率分别为1．0、1．0、1．0、2．0．3．0、3．0、4．0、6．0、8．0kHz时的纯音听阈值之间有相对最大的负相关系数。f0为0．5、0.75、1．0、1．5、2．0、3．0、4．0、6．0、8．0kHz时所对应的量相关纯音听阈测试频率分别为0．75、1．0、1．5、2．0、2．5、3．5、5．0、6．0、8．0kHz。结论DPOAE测值与纯音听阈值之间有负相关关系，且DPOAE测试频率与纯音听阈测试频率间存在一定的对应关系。     

Otoacoustic emissions and persistent tinnitus after acute acoustic trauma

OBJECTIVES: To follow up the auditory status of military personnel after an acute acoustic trauma and to identify the possible predictive value of hearing thresholds and otoacoustic emissions during the first 24 hours after the acoustic trauma. STUDY DESIGN: A group of 24 young military subjects, aged 22 +/- 2.3 years, without any otologic problem before the acoustic trauma, were examined at three time intervals after an accidental acoustic trauma caused by the discharge of a firearm: 24 hours, 72 hours, and 15 days. METHODS: Each subject was submitted to medical examination and to a questionnaire detailing the circumstances of the acoustic trauma. Pure tone audiometry was performed from 1 to 8 kHz per half octave. Transiently evoked otoacoustic emissions were recorded in the nonlinear mode at 80 dB pSPL, and distortion product otoacoustic emissions were recorded from 1 to 6 kHz, using a distortion product-gram type procedure, at 65/55 dB SPL, with f2/f1 = 1.22. Two groups of subjects were defined: group 1 (n = 8) represented subjects with short-lasting tinnitus (<72 h) and group 2 (n = 16) subjects with long-lasting tinnitus (>72 h). RESULTS: Hearing thresholds did not differ significantly between these two groups 24 hours after the acoustic trauma. However, otoacoustic emissions showed significantly lower amplitudes 24 hours after the acoustic trauma in subjects showing a longer lasting tinnitus. CONCLUSION: Otoacoustic emissions appear to be a better predictor of the persistence of tinnitus than hearing thresholds alone 24 hours after an acute acoustic trauma.     

Validating self-reporting of hearing-related symptoms against pure-tone audiometry,otoacoustic emission,and speech audiometry

Objective: To validate self-reported hearing-related symptoms among personnel exposed to moderately high occupational noise levels at an obstetrics clinic. Design: Sensitivity, specificity, and predictive values were calculated for questionnaire items assessing hearing loss, tinnitus, sound sensitivity, poor hearing, difficulty perceiving speech, and sound-induced auditory fatigue. Hearing disorder was diagnosed by pure-tone audiometry, distortion product otoacoustic emissions, and HINT (Hearing In Noise Test). Study sample: Fifty-five female obstetrics personnel aged 22–63 participated; including 26 subjects reporting hearing loss, poor hearing, tinnitus, or sound sensitivity, and 29 randomly selected subjects who did not report these symptoms. Results: The questionnaire item assessing sound-induced auditory fatigue had the best combination of sensitivity?≥85% (95% CIs 56 to 100%) and specificity?≥70% (95% CIs 55 to 84%) for hearing disorder diagnosed by audiometry or otoacoustic emission. Of those reporting sound-induced auditory fatigue 71% were predicted to have disorder diagnosed by otoacoustic emission. Participants reporting any hearing-related symptom had slightly worse measured hearing. Conclusions: We suggest including sound-induced auditory fatigue in questionnaires for identification of hearing disorder among healthcare personnel, though larger studies are warranted for precise estimates of diagnostic performance. Also, more specific and accurate hearing tests are needed to diagnose mild hearing disorder.     

Expression of Na+/H+ exchanger isoforms in normal human nasal epithelial cells and functional activity of Na+/H+ exchanger 1 in intracellular pH regulation

Objective That static ear canal air pressure (ECP) influences the frequency of spontaneous otoacoustic emissions (SOAEs) suggests that it may influence intracochlear, in addition to middle ear, processes. A previous study suggested that ECP influences pure tone pitch perception at 1,000 Hz, which was interpreted as indicating an effect on the cochlear place-frequency map. The present study extended investigations of this effect to 500 and 4,000 Hz.

Materials and Methods Nine normal-hearing listeners performed interaural pitch matching with monaural ECPs of 0 and -300 daPa.

Results Some indications of a small downward pitch shift (mean 0.2%) at 500 Hz were observed, which were marginally statistically significant at the 5% level. No pitch shifts were observed at 4,000 Hz.

Conclusions ECP does not influence pitch to the extent suggested previously or by SOAE frequency shifts. No evidence was found to support the notion that ECP influences the place-frequency map.     

Acute Effects of Alcohol on Auditory Thresholds and Distortion Product Otoacoustic Emissions in Humans

Objective—To investigate the acute effects of alcohol consumption on pure-tone thresholds (PTs) and distortion product otoacoustic emissions (DPOAEs) in humans. Material and Methods—Eight healthy adults were asked to drink alcohol to the clinical intoxication level. PTs and DPOAEs were determined serially before and after alcohol ingestion. Results—Alcohol had no effect on PTs. DPOAE amplitudes above 5500 Hz dropped 30 min and 1 h after alcohol ingestion, returning to the pre-test level 2 h after ingestion. Conclusion—In humans, acute alcohol consumption to the intoxication level may cause a temporary reduction in DPOAE amplitudes at high frequencies without affecting auditory thresholds.