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.     

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。     

Transiently evoked otoacoustic emissions as a prognostic indicator in idiopathic sudden hearing loss

Idiopathic sudden sensorineural hearing loss (ISHL) remains a controversial topic. So far, there are no proven objective auditory factors to establish prognosis. Otoacoustic emissions reflect the functional integrity of the outer hair cells. The aim of this study was to assess the presence of transiently evoked otoacoustic emissions (TEOAEs) in the early stages of ISHL cases as a prognostic indicator. Thirty patients hospitalized for ISHL were included in the study. All patients underwent pure-tone audiometry (PTA) and TEOAE recordings on the admission day and at least three measures on the subsequent eight days. The audiometric threshold improvement at each frequency was correlated with the TEOAE parameters on each measure. Finally, the presence of TEOAEs on early examination was correlated with PTA threshold improvement. Twenty-three out of 30 patients experienced hearing recovery. Fourteen of the recovered patients had recordable TEOAEs or acceptable TEOAE peak amplitudes in some frequency bands on the first two measures, despite having audiometric thresholds greater than 40 dB HL. It thus seems that TEOAEs might serve as a clinical tool for prediction of recovery in ISHL cases.     

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.     

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.     

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.     

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.     

Distortion product otoacoustic emissions in sensorineural hearing loss

The measurement of distortion product otoacoustic emissions (DPOE), one of the types of otoacoustic emissions (OES) gives the possibility of frequency--specific, objective assessment of cochlear function. Data were collected from 67 ears with sensorineural hearing loss and 30 normally hearing ears as a control group. Percentage of DPOE response detected above the noise floor level was evaluated in relation to the pure-tone audiometric thresholds. Analysis of correlation coefficient between amplitude of DPOE and degree of hearing loss for respective frequencies was performed. DPOE were detected in significantly lower percentage in the group of ears with sensorineural hearing loss exceeding 60 dB HL. The amplitude of DPOE decreased with the degree of hearing loss detected in pure-tone audiometry. There was statistically significant correlation (r -0.65(-)-0.85) in all examined frequencies between DPOE and hearing loss (1-6 kHz).     

单侧突发性聋患者对侧耳耳声发射分析

目的研究突发性聋患者单耳发病时对侧耳的耳蜗功能状态。方法利用Capella耳声发射仪对单侧突发性聋患者的对侧耳50例(50耳,病例组)及正常人30例(60耳,对照组)分别进行瞬态声诱发耳声发射(TEOAE)及畸变产物耳声发射(DPOAE)检测,记录和分析TEOAE的通过率及各频率DPOAE的检出率、幅值。结果①TEOAE通过率对照组为100%,病例组为75%,两组比较差异有统计学意义(χ2=20.84,P<0.01);②DPOAE检出率在0.5、0.75、1.0、3.0、4.0 kHz频点上,病例组低于对照组(P<0.05或P<0.01);③与对照组相比,病例组各频率DPOAE的幅值均降低,差异有统计学意义(P<0.05或P<0.01)。结论部分突发性聋患者的对侧耳已出现早期耳蜗功能受累,利用耳声发射分析方法可在听力损失出现之前早期发现此类病变。     

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.     

Evoked otoacoustic emissions in diagnosis of cochlear hearing disorders]

The authors consider the possibility of routine use of evoked otoacoustic emissions (EOE) in diagnosis of sensory hearing loss by comparison of EOE curves with relative curves obtained by pure tone audiometry. 180 ears with sensory hearing loss of different aetiologies were examined. EOE were obtained by application of Bray and Kemp's Evoked Otoacustic Measurement Package (ILO88). The results obtained show a close correlation between presence of EOE and real hearing losses of different frequencies obtained by pure tone audiometric evaluation. We could detect no EOE with hearing losses over 50 dB HL at 500 Hz, 40 dB HL at 1000 Hz, 50 dB HL at 2000 Hz and 85 dB HL at 4000 Hz. With a rate of middle hearing loss over 45 dB HL we also did not find EOE for the whole frequency range. On the base of this study, the authors conclude that EOE explore the functional integrity of those parts of the cochlea that correspond to the middle frequencies of hearing range. If EOE are not detectable, statements on the nature and extent of hearing loss on the base of this examination are not valid.     

Distortion product otoacoustic emissions as a prognostic factor for idiopathic sudden sensorineural hearing loss

We investigated distortion product otoacoustic emissions (DPOAE) as a prognostic factor in idiopathic sudden sensorineural hearing loss (ISSHL) patients with the time-dependent Cox proportional-hazards model. We also compared the importance of the prognostic factors that are reported in the literature. 108 patients with ISSHL were included. Both DPOAE and pure tone audiometry were performed everyday for a maximum of 7 days during admission and followed every other week or monthly after discharge. All DPOAE amplitudes were analyzed at 2f1-f2--namely 1093, 1375, 1750, 2187, 2781, 3500, 4375, and 5500 Hz. The average of two series of DPOAE intensity corrected for the noise level in eight frequencies was coded as dichotomous at > or =6 or <6 dB. We selected the most updated DPOAE at 3 days or more before the assessment of recovery into the analysis. The potential confounders including age, sex, history of vertigo at onset, history of hypertension, diabetes, coronary arterial disease, and stroke, configuration and severity of initial pure tone audiometry, the duration from onset to treatment, auditory brainstem response (ABR), vestibular evoked myogenic potential (VEMP), and plasma triglyceride and cholesterol levels, hemoglobin level, and erythrocyte sedimentation rate were collected for evaluation. The results showed that a better DPOAE amplitude was a significantly good prognostic indicator both in univariate analysis (recovery rate ratio = 3.626, 95% CI = 2.119-6.205, p < 0.0001) and multivariate analysis (recovery rate ratio = 2.94, 95% CI = 1.537-5.624, p = 0.0011). The Kaplan-Meier estimates showed that the younger age group (< or =40 years) with better initial pure tone audiometry (<65 dB) represented a better prognosis that was compatible with previous literature (log-rank test, p = 0.0297 and p = 0.0019 respectively). In the univariate analysis, normal ABR and VEMP waveforms were associated with a better prognosis (ABR: recovery rate ratio = 2.984, 95% CI = 1.742-5.112, p < 0.0001; VEMP: recovery rate ratio = 1.978, 95% CI = 1.183-3.305, p = 0.0093). The configuration of initial audiometry was also a significant prognostic factor that patients with scale-out type (recovery rate ratio = 0.228, 95% CI = 0.089-0.584, p = 0.002) and tent type (recovery rate ratio = 0.081, 95% CI = 0.008-0.778, p = 0.0295) were associated with a poorer prognosis than those with the flat type in the multivariate analysis. In this study, the time-dependent Cox proportional-hazards model established the prognostic value of DPOAE for ISSHL patients. This model can also be used for comparison of different treatment protocols. In addition, the further development of a predictive model based on this method is worthy of being investigated.     

Stimulated otoacoustic emissions in children with sensorineural hearing loss

Our previous studies of stimulated oto-acoustic emissions (OAEs) have revealed that the OAE threshold indicates the grade of inner ear impairment. The present study is a survey of OAE in children of school age. The mean OAE threshold values of 113 ears with normal hearing and 45 ears with functional deafness were 5.9 dB nHL and 6.2 dB nHL, respectively. In sensorineural loss the value was noted to increase according to its grade, classified into four groups, measuring 37.2 dB nHL in the group with severe loss higher than 91 dB. The findings suggest that the OAE threshold is useful for an indicator of inner ear function in children. There still remains the problem to be solved by a contrivance of noise removal for application of OAE to hearing tests in children of pre-school age.     

双耳突聋与单耳突聋的临床比较

目的:对比双耳突发性聋与单耳突发性聋的临床特点及治疗效果的异同。方法:回顾性分析480例突发性聋患者,将其分为单耳组(440例)和双耳组(40例),对2组的临床特点及疗效进行比较。结果:与单耳突发性聋比较,双耳突发性聋更多见于糖尿病、高脂血症患者,并且年龄越大,发生双耳突发性聋的可能性越大。在双耳组中28耳治疗有效,有效率为35%;单耳组中228耳治疗有效,有效率为56.4%,两者差异有统计学意义。结论:双耳突发性聋和单耳突发性聋可能具有不同的病理生理机制和预后,从临床上认识两者间的异同,有助于治疗方案的制定和预后的评估。     

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.     

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.     

A cochlear schwannoma presenting with sudden hearing loss

A cochlear schwannoma is a rare tumor that arises from the cochlear nerve. Clinically, a cochlear schwannoma mimics the clinical features of sudden deafness or Meniere's disease. We report a case of cochlear schwannoma that presented with sudden hearing loss, which was diagnosed with gadolinium-enhanced magnetic resonance imaging and removed using a transotic approach.     

On a possible prognostic value of otoacoustic emissions: a study on patients with sudden hearing loss

Otoacoustic emissions (OAE) and pure tone audiogram (PTA) were examined in 26 ears of 25 patients suffering from sudden hearing loss from the 1st day to up to 505 days following the drop of hearing to test the hypothesis whether the OAEs are capable of delivering predictive information about the recovery process. The patients were selected from 50 candidates according to the following criteria: one or both ears exhibited a systematic and significant recovery of pure tone threshold in at least one frequency, OAEs were detectable and PTA available, a conductive hearing loss was excluded, and the auditory brainstem responses (ABR) yielded no signs of retrocochlear disorders. Transitory evoked otoacoustic emissions (TEOAE) and distortion product otoacoustic emissions (DPOAE) were measured under constant stimulus and recording conditions in three to nine sessions. The relation between OAE level and actual pure tone threshold was subject to a regression analysis. The correlation between both parameters is small but significant. Even smaller correlations are observed if the OAE level is related to former hearing loss, whereas the correlation improves if the OAE level is compared to the pure tone threshold measured in a later session. The slopes of individual trajectories that connect the successive results of one ear in a plane defined by hearing loss and OAE level show a remarkable accumulation around zero, i.e., in many cases the OAEs remain unchanged even if the hearing loss decreases. The comparison of the OAE levels measured at an early stage with later audiograms shows that there are only a small number of cases with small initial emissions and good final threshold or large initial emissions and bad final threshold. This means that small initial OAEs end up with a remaining final hearing deficit, whereas a high OAE level immediately after drop of threshold correlates with good outcome. The reliability of an individual prediction based on the OAE level combined with the threshold after sudden hearing loss and the consequences for the physiologic mechanisms underlying the sudden hearing loss remain to be proved in further investigations.