Evoked otoacoustic emissions and sensorineural hearing loss

Following Kemp's original studies, several others have confirmed the existence of otoacoustic emissions. Their clinical relevance remains, however, to be clarified. The various published studies have concerned small series. This study sought to specify otoacoustic emission characteristics in relation to sensorineural hearing loss (148 ears of 76 subjects). The results show that the presence of otoacoustic emissions drops as a function of hearing loss and that there is a highly statistically significant correlation between otoacoustic emission threshold and hearing loss at the 1000-Hz frequency. Otoacoustic emissions are never found when hearing loss at 1000 Hz exceeds 40 dB hearing level and when the mean audiometric hearing loss (at 500, 1000, 2000, and 4000 Hz) exceeds 45 dB hearing level. The main practical conclusion is that otoacoustic emission presence indicates middle frequency functional integrity of the outer hair cells of Corti's organ. Absence of otoacoustic emissions is harder to interpret.     

Spontaneous otoacoustic emissions and sensori-neural hearing loss.

This study sought to clarify the clinical relevance of spontaneous otoacoustic emissions (SOAEs) and to define the hearing loss level (and frequency) at which absence of SOAE is found. Findings from 126 ears of patients with sensori-neural hearing loss showed an incidence of SOAEs in 18.25% of the cases (23 out of 126 ears). SOAEs were never found when hearing loss at 1,000 Hz exceeded 10 dB. The presence of SOAE seems to indicate a good cochlear functioning at least in the mid-frequencies. Although the incidence of SOAEs is markedly lower than that of evoked otoacoustic emissions (EOAEs), SOAE recording is shown to be a good test, rapid, non-invasive for audiological screening, the presence of SOAE confirming a hearing threshold of less than 10 dB at 1,000 Hz, the absence of SOAE being inconclusive.     

Occupational hearing loss: screening with distortion-product otoacoustic emissions

Hearing assessment of applicants for occupational hearing loss compensation can be a time-consuming process. An accurate screening procedure that is sensitive to occupational hearing loss may have application in many situations. The present study developed distortion-product otoacoustic emission (DPOAE) screening criteria to identify subjects likely to meet the Hong Kong requirements for occupational hearing loss compensation, namely a bilateral sensorineural loss > or = 40 dB HL (average of 1000, 2000 and 3000 Hz). The screening criteria of 1500 and/or 2000 Hz, with a signal-to-noise ratio of > 0 or 3 dB, yielded high sensitivity and specificity. DPOAE measures therefore have the potential to accurately indicate possible occupational hearing loss. However, DPOAEs should be used as a screening tool only, as conventional puretone audiometry remains the more comprehensive measure of hearing sensitivity.     

Occupational hearing loss: screening with distortion-product otoacoustic emissions

Hearing assessment of applicants for occupational hearing loss compensation can be a time-consuming process. An accurate screening procedure that is sensitive to occupational hearing loss may have application in many situations. The present study developed distortion-product otoacoustic emission (DPOAE) screening criteria to identify subjects likely to meet the Hong Kong requirements for occupational hearing loss compensation, namely a bilateral sensorineural loss ≥ 40 dB HL (average of 1000, 2000 and 3000 Hz). The screening criteria of 1500 and/ or 2000 Hz, with a signal-to-noise ratio of >0 or 3 dB, yielded high sensitivity and specificity. DPOAE measures therefore have the potential to accurately indicate possible occupational hearing loss. However, DPOAEs should be used as a screening tool only, as conventional pure-tone audiometry remains the more comprehensive measure of hearing sensitivity.     

Identification of hearing loss in newborns by transient otoacoustic emissions

OBJECTIVE: More than 90% of congenital hearing loss cases are of cochlear origin. There are two methods for newborn hearing screening: the transient otoacoustic emission (TEOAE) or (ABR) screening. When TEOAE is used for hearing screening patients, newborn with a neural hearing loss are not discovered. MATERIALS: In the present study TEOAEs were obtained from 3,048 newborns from both ears in patients with and without risk factors for hearing loss in the history. All newborns who did not pass TEOAE in the 2nd screening (uni or bilaterally) underwent additional audiologic tests. RESULTS: In the first screening 150 (4.5%) of the newborns newborn did not pass the screening and 30 (0.98%) did not pass in the second screening. In nine newborns with unilateral absent TEOAE and in two newborns a deafness was confirmed, with one side cochlear and on the other side retrocochlear. Both patients received cochlear implants before the 2nd year of age. In 21 newborns with absent TEOAE bilaterally, five had moderate sensorineural hearing loss bilaterally and in nine patients profound hearing loss (90-100 dB) or deafness was confirmed. Of 3,048 newborns there were 1,355 with a risk of hearing loss and in 12 (0.88%) newborns bilateral hearing loss or deafness was confirmed; of the 1663 newborns without risk of hearing loss in the history, in four (0.24%) newborn deafness or bilateral sensorineural hearing loss in the range of 45-65 dB were confirmed. CONCLUSION: When the newborn has an absent TEOAE uni or bilaterally, we need to inform the parents and to recommend additional screening and other audiologic tests to confirm or exclude hearing loss.     

单侧耳蜗性聋患者对侧耳耳声发射的表现

目的 :探讨致聋因素在致单耳发病时对对侧耳潜在的影响。方法 :利用OtodynamicILO96耳声发射分析仪 ,对 35例单侧耳蜗性聋患者 (分为 5组 :发病 2个月以内的突发性聋 9例为S1组 ,发病 1年以上的突发性聋 6例为S2 组 ,梅尼埃病 13例分为M1、M2 组 ,不明机理的耳蜗性聋 7例为UNK组 )对侧耳瞬态诱发性耳声发射 (TEOAE)的反应幅值、反应重复率及频带的重复率 ,畸变产物耳声发射 (DPOAE)曲线特点及 1～ 5kHz反应幅值进行分析比较。结果 :S1组、M2 组TEOAE的反应幅值、反应重复性、频带重复性明显低于正常值 ,DPOAE幅值明显降低 ;S2 组、M1组、UNK组TEOAE和DPOAE正常。结论 :在不同致聋因素中 ,有的对单耳产生损伤作用 ,有的对双耳产生损伤作用。     

Prediction of hearing outcomes by distortion product otoacoustic emissions in patients with idiopathic sudden sensorineural hearing loss

Objective

To investigate whether distortion product otoacoustic emissions (DPOAEs) can be a prognostic indicator of hearing outcomes in patients with idiopathic sudden sensorineural hearing loss (ISSNHL).

Methods

Seventy-eight consecutive patients with ISSNHL were enrolled. DPOAEs were measured at the first hospital visit. Two primary pure tones with a frequency ratio (f2/f1) of 1.2 were used at non-equal sound pressure levels (L1/L2 = 80/70 dB SPL). The DPOAE amplitude was measured at the 11 frequencies of 2f1-f2 with f2 varying from 593 to 6031 Hz. All the patients received steroid administration in combination with hyperbaric oxygen (HBO) therapy. Hearing recovery was evaluated by the improvement in hearing compared to the unaffected contralateral ear. Correlations between the hearing improvement rate and five potential prognostic factors (the DPOAE amplitude, patient's age, days from onset to the start of treatment, initial hearing level, and presence of vertigo) were examined by simple and multiple regression analyses.

Results

The net DPOAE amplitude in patients with hearing improvement rate ≥50% was significantly larger than that with hearing improvement rate <50% at f2 frequencies of 3031 and 4812 Hz (unpaired Student's t-test, p < 0.05). A simple regression analysis showed that the hearing improvement rate significantly correlated with the net DPOAE amplitude at f2 frequencies of 3031 and 4812 Hz, but not with that at the other f2 frequencies tested. The correlation coefficients were 0.528 and 0.522 for 3031 and 4812 Hz, respectively, with p values <1 × 10⁻⁶. In a multiple regression analysis, the partial correlation coefficients of the net DPOAE amplitude were 0.308 and 0.246 with p values of 0.008 and 0.036 for 3031 and 4812 Hz, respectively.

Conclusion

The significant correlation between hearing recovery and DPOAEs measured before treatment indicates that DPOAEs are a potentially useful means of predicting hearing prognosis in ISSNHL.     

Alternative distortion product otoacoustic emissions and hearing loss in a clinical population

Parameters of the alternative distortion product otoacoustic emissions (DPOAEs) 4f1-3f2, 3f1-2f2, 2f2-f1, 3f2-2f1 and 4f2-3f1 as well as the cubic distortion product 2f1-f2 were extracted from the ILO 92 binary files of patients reported on earlier (Lind, 1998). The DPOAEs were recorded at 18 stimulus levels between 19 and 70 dB SPL. The prevalence of at least one valid DPOAE data-point varied from 74% at 4f1-3f2 to 100% at 2f2-f1. The mean number of valid points was six for 2f2-f1, but generally below four for the others. The mean maximum amplitude for the alternative DPOAEs was 6-12 dB below that of the 2f1-f2. The mean maximum signal-to-noise-ratio (SNR) was between 2.5 and 3.5 dB SPL for the four most peripheral emissions and increased to 6.7 dB SPL for the 2f2-f1. As reported earlier, the 2f1-f2 distortion was fairly well correlated with hearing threshold at 2 kHz. The 2f2-f1 shows some correlation with hearing loss at frequencies above f2, but the other DPOAEs were not correlated with hearing loss at any frequency, which may suggest different generating mechanisms and/or sites. The inf1uence of age on maximum amplitude was small but significant for all DPOAEs.     

Preserved otoacoustic emissions in postparotitis profound unilateral hearing loss: a case report

We report a case of a profound unilateral sensorineural hearing loss following epidemic parotitis, with good response of otoacoustic emissions. The patient was a 12-year-old girl who had developed a unilateral hearing impairment 2 weeks after the onset of mumps. Pure tone audiometry confirmed a profound left sensorineural hearing loss. The affected ear showed an absence of auditory brain stem responses, whereas transient evoked otoacoustic emissions and distortion product otoacoustic emissions were preserved. Epidemic parotitis virus is likely responsible for an impairment of inner hair cells, primary afferent fibers or their synapses, or a combination of these areas, and it does not seem to have a specific tropism for cochlear outer hair cells. Further follow-up will be necessary to differentiate the present case from auditory neuropathy.     

Case report of a child with otoacoustic emissions and profound hearing loss in whom otoacoustic emissions were preserved after cochlear implantation

Abstract

Objective and importance

To highlight the complications of using hydroxyapatite (HA) bone cement when implanting a cochlear implant (CI) device.

Clinical presentation

A case series of three patients who had undergone cochlear implantation are presented. A bony defect was seen in the external auditory meatal wall posteriorly in all three cases. This was intimately related to the site of HA bone cement, which had been used to anchor the electrode array at the time of the original implantation. Persistent otorrhoea was usually a feature at clinical presentation.

Intervention (and technique)

Removal of the HA bone cement and repair of the bony defect has resulted in resolution of the otorrhoea and a functioning CI is present in all cases without further complications.

Conclusion

The use of HA bone cement in cochlear implantation may cause dehiscence of the external auditory meatal wall. Our experience has shown that the electrode array does not need to be secured with cement. It is therefore recommended by this centre that HA cement should not be used to secure the electrode array in cochlear implantation surgery.     

Biologic activity of mitochondrial metabolites on aging and age-related hearing loss

HYPOTHESIS: Compounds that upregulate mitochondrial function in an aging model will improve hearing and reduce some of the effects of aging. BACKGROUND: Reactive oxygen metabolites (ROM) are known products of oxidative metabolism and are continuously generated in vivo. More than 100 human clinical conditions have been associated with ROM, including atherosclerosis, arthritis, autoimmune diseases, cancers, heart disease, cerebrovascular accidents, and aging. The ROM are extremely reactive and cause extensive DNA, cellular, and tissue damage. Specific deletions within the mitochondrial DNA (mtDNA) occur with increasing frequency in age and presbyacusis. These deletions are the result of chronic exposure to ROM. When enough mtDNA damage accrues, the cell becomes bioenergetically deficient. This mechanism is the basis of the mitochondrial clock theory of aging, also known as the membrane hypothesis of aging. Nutritional compounds have been identified that enhance mitochondrial function and reverse several age-related processes. It is the purpose of this article to describe the effects of two mitochondrial metabolites, alpha-lipoic acid and acetyl L-carnitine, on the preservation of age-related hearing loss. METHODS: Twenty-one Fischer rats, aged 24 months, were divided into three groups: acetyl-l-carnitine, alpha-lipoic acid, and control. The subjects were orally supplemented with either a placebo or one of the two nutritional compounds for 6 weeks. Auditory brainstem response testing was used to obtain baseline and posttreatment hearing thresholds. Cochlear, brain, and skeletal muscle tissues were obtained to assess for mtDNA mutations. RESULTS: The control group demonstrated an expected age-associated threshold deterioration of 3 to 7 dB in the 6-week study. The treated subjects experienced a delay in progression of hearing loss. Acetyl-l-carnitine improved auditory thresholds during the same time period (p<0.05). The mtDNA deletions associated with aging and presbyacusis were reduced in the treated groups in comparison with controls. CONCLUSIONS: These results indicate that in the proposed decline in mitochondrial function with age, senescence may be delayed by treatment with mitochondrial metabolites. Acetyl-l-carnitine and alpha-lipoic acid reduce age-associated deterioration in auditory sensitivity and improve cochlear function. This effect appears to be related to the mitochondrial metabolite ability to protect and repair age-induced cochlear mtDNA damage, thereby upregulating mitochondrial function and improving energy-producing capabilities.     

The effects of aging on distortion-product otoacoustic emissions in adults with normal hearing

OBJECTIVES: The focus of this study was to determine whether deterioration in cochlear function, as evaluated by distortion-product otoacoustic emission (DPOAE), exists before the elevation of audiometric thresholds occurs during the course of aging. In previous research, variability in normal audiometric thresholds likely contributed to the aging effect on OAE data. Therefore, in selecting subjects, we applied the stringent criterion in pure-tone thresholds (PTT) to limit dispersion among normal-hearing thresholds. DESIGN: We evaluated 331 subjects (136 men and 195 women) of a population-based sample of 2259 adults aged 40 to 82 yr who took part in the Longitudinal Study of Aging. We chose subjects according to the audiometric criterion that thresholds at any of five frequencies, namely 500, 1000, 2000, 4000, and 8000 Hz, did not exceed 15 dB HL. The mean age of our subjects was 48.3 +/- 7.4 yr (range, 41 to 72 yr) in men and 49.6 +/- 7.6 yr (range, 41 to 80 yr) in women. In a univariate analysis, analysis of variance was performed on DPOAE amplitudes and noise estimates at 22 test frequencies, as well as on the PTT. Age groups (40s, 50s, 60s, and above) were considered separately for men and women, without adjustment for any confounding variables. In a multivariate approach, general linear model analyses were performed to focus attention on the impact of age as a continuous variable, and on the influence of PTT on DPOAE levels. The multivariate analysis was conducted separately for men and women. DPOAE amplitudes at nine test frequencies were set as objective variables. Age (continuous variable), PTT at the corresponding test frequency, and interaction between age and PTT at the corresponding test frequency were evaluated as explanatory variables with adjustment for static admittance, history of ear disease (yes = 1), and history of occupational noise exposure (yes = 1). RESULTS: Of the 22 test frequencies, we found a statistically significant difference in DPOAE amplitudes among age groups at four test frequencies in men, ranging from 4761 to 6165 Hz, and at all but the 3088 Hz test frequency in women. Despite the stringent audiometric inclusion criterion, statistically significant differences in the mean PTT among the age groups were observed at 4000 Hz in men and at all five tested frequencies in women. Multivariate analyses demonstrated a significant negative effect of age on DPOAE levels at 1086 Hz f2 frequency in men and at the 1184, 2002, 2185, 4004, and 4358 Hz f2 frequencies in women. Regarding PTT, neither main nor interactive effect on DPOAE amplitude was statistically significant at any of nine test frequencies. The goodness-of-fit of the model, in terms of R2, ranged from 0.05 to 0.11 in men and from 0.11 to 0.18 in women. CONCLUSIONS: The present analyses substantiated the hypothesis DPOAEs deteriorate with age independently of hearing sensitivity. The aging effect on DPOAE measures was observed more in women than in men. We conclude that DPOAE measurements in audiometrical normal-hearing elderly may provide early indications of cochlear damage because of aging.     

Diplacusis,hearing threshold and otoacoustic emissions in an episode of sudden,unilateral cochlear hearing loss

Limited data are available on the relationship between diplacusis and otoacoustic emissions and sudden hearing threshold changes, and the detail of the mechanism underlying diplacusis is not well understood. Data are presented here from an intensively studied single episode of sudden, non-conductive, mild hearing loss with associated binaural diplacusis, probably due to a viral infection. Treatment with steroids was administered for 1 week. This paper examines the relationships between the hearing loss, diplacusis and oto-acoustic emissions during recovery on a day-by-day basis. The hearing thresholds were elevated by up to 20 dB at 4 kHz and upwards, and there was an interaural pitch difference up to 12% at 4 and 8 kHz. There was also a frequency-specific change in transient evoked otoacoustic emission ( TEOAE) and distortion-product otoacoustic emission (DPOAE) level. DPOAE level was reduced by up to 20 dB, with the greatest change seen when a stimulus with a wide stimulus frequency ratio was used. Frequency shifts in the 2f2 – f1 DPOAE fine structure corresponded to changes in the diplacusis. Complete recovery to previous levels was observed for TEOAE, DPOAE and hearing threshold. The diplacusis recovered to within normal limits after 4 weeks. The frequency shift seen in the DPOAE fine structure did not quite resolve, suggesting a very slight permanent change. The timecourses of TEOAE, diplacusis and hearing threshold were significantly different; most notably, the hearing threshold was stable over a period when the diplacusis deteriorated. This suggests that the cochlear mechanisms involved in diplacusis, hearing threshold and OAE may not be identical.     

Click- and tone-burst-evoked otoacoustic emissions in normally hearing ears and in ears with high-frequency sensorineural hearing loss

Summary Otoacoustic emissions (OAEs) evoked by clicks and tone bursts (TBs) were measured using a minor modification of the 1987 Bray and Kemp system in normal and hearing-impaired ears with high-frequency sensorineural hearing loss. Sixty ears of 60 subjects were tested. The average behavioral hearing threshold of 20 normally hearing ears was measured for the different nonlinear stimulus groups and defined as 0 dBnHL. Emissions were recorded in another 20 normally hearing ears and in 20 ears with steep high-frequency sensorineural hearing loss above 2 kHz. An unfiltered click of 80 s duration and TBs at frequencies of 0.5, 1, 2, 3, 4, 5, and 6 kHz served as stimuli. The ears with high-frequency hearing loss were clearly distinguished from the normal ears in that emission energy decreased with higher frequency stimuli above 2 kHz. The mean slopes of the response-growth functions were significantly higher at lower audiometric thresholds. The normal ears showed a slope of 0.21–0.35dB/dBnHL above 2kHz while the slope of the pathological ears was 0.04–0.13 dB/dBnHL. These differences in TBOAEs could possibly be used clinically to carry out hearing tests that are more frequency-specific than those measuring solely click-evoked OAEs. Pathological ears had emissions in the lower frequency range, where they had a normal audiometric threshold. However, these emissions had significantly far lower amplitudes at frequencies around 0.5 and 1 kHz when compared to normal ears. This reduced emission energy may indicate a cochlear impairment of the pathological ears in frequency ranges where they still had normal audiometric thresholds.Portions of this report were presented at the ADANO (Arbeitsgemeinschaft Deutscher Audiologen und Neurotologen) Meeting in Flims, Switzerland, March 29–31, 1990 Offprint requests to: R. Hauser     

畸变产物耳声发射在伪聋和夸大性聋检测中的应用

目的：探讨畸变产物耳声发射（DPOAE）对伪聋和夸大性聋的鉴别诊断作用。方法：采用ILO 96耳动态分析仪对外伤后诉听力下降,而又不配合纯音听阈（PTT）检测的患者进行DPOAE检测与分析。结果：经PTT检测的129例（150耳）外伤性听力下降患者中,有102例（121耳）,作DPOAE检测结果显示伪聋占66．12％（80／121）,夸大性聋占33．88％（41／121）。经ABR检测反应阈值,证实DPOAE检测结果客观、可靠。结论：DPOAE作为外伤后听力损失鉴别诊断的常规检测方法,可对伪聋和夸大性聋作出客观、可靠的诊断和鉴别诊断。     

Contralateral normal ear after mastoid surgery: evaluation by otoacoustic emissions (mastoid drilling and hearing loss)

Mastoid drilling can cause transient hearing loss in the contralateral normal hearing ear. A study was designed to evaluate hearing in the contralateral normal ear before and after the mastoid surgery in a longitudinal manner and find out the duration of this temporary hearing loss. Twenty-two patients requiring mastoid surgery in their diseased ears, having contralateral normal ear were included. Pure tone audiometry and otoacoustic emissions (OAEs) were utilized for baseline evaluation. OAEs were repeated during the immediate postoperative period and daily up to the 6th postoperative day. The amplitudes of the OAEs of contralateral normal ears were found affected immediately after surgery and progressive improvement was detected with full recovery at 72-96 h. None of the patients had permanent deterioration in OAE amplitudes. The burs used during mastoid surgery can cause temporary hearing threshold changes in the contralateral ears. This adverse effect recovers spontaneously within 72-96 h postoperatively.     

Diplacusis, hearing threshold and otoacoustic emissions in an episode of sudden, unilateral cochlear hearing loss

Limited data are available on the relationship between diplacusis and otoacoustic emissions and sudden hearing threshold changes, and the detail of the mechanism underlying diplacusis is not well understood. Data are presented here from an intensively studied single episode of sudden, non-conductive, mild hearing loss with associated binaural diplacusis, probably due to a viral infection. Treatment with steroids was administered for 1 week. This paper examines the relationships between the hearing loss, diplacusis and otoacoustic emissions during recovery on a day-by-day basis. The hearing thresholds were elevated by up to 20 dB at 4kHz and upwards, and there was an interaural pitch difference up to 12% at 4 and 8 kHz. There was also a frequency-specific change in transient evoked otoacoustic emission (TEOAE) and distortion-product otoacoustic emission (DPOAE) level. DPOAE level was reduced by up to 20 dB. with the greatest change seen when a stimulus with a wide stimulus frequency ratio was used. Frequency shifts in the 2f2-fi DPOAE fine structure corresponded to changes in the diplacusis. Complete recovery to previous levels was observed for TEOAE, DPOAE and hearing threshold. The diplacusis recovered to within normal limits after 4 weeks. The frequency shift seen in the DPOAE fine structure did not quite resolve, suggesting a very slight permanent change. The time-courses of TEOAE. diplacusis and hearing threshold were significantly different: most notably, the hearing threshold was stable over a period when the diplacusis deteriorated. This suggests that the cochlear mechanisms involved in diplacusis, hearing threshold and OAE may not be identical.