Objective Audiometry Research Articles

Mitigation of Effect Modification by Psychological Status in Patients With Hearing Loss

Although patient-reported outcomes provide valuable insights, these subjective data may not align with objective test results. Hearing loss is a pervasive problem, such that concordance between subjective perceptions of hearing ability and objective audiogram assessments would be beneficial. To determine (1) whether psychological status is an effect modifier of the association between subjective patient reports of hearing ability and objective audiometry results, and (2) whether any effect modification observed in standard static questionnaires would be either mitigated or exacerbated by adaptive testing based on Item Response Theory analyses. This diagnostic study at a tertiary care center and community-based practice included consecutive adults who presented with queries related to hearing loss. Participants were recruited and enrolled and data analyses occurred from 2022 to 2024. Participants prospectively reported their hearing-specific abilities through either a standard static or adaptive version of the Inner Effectiveness of Auditory Rehabilitation (EAR) scale, alongside validated measures of their mental health and audiometry. Word recognition scores (WRS) and pure tone averages (PTA) were used to analyze audiometric testing. The association between subjective Inner EAR results and audiometry was evaluated. Stratified analyses were used to assess for effect modification by psychological status. The results of standard static and adaptive testing were compared. In this study of 395 patients (mean [range] age, 55.9 [18-89] years; 210 [53.2%] female), standard static Inner EAR mean scores were appropriately higher in patients with higher (better) WRS (50.7, 95% CI, 46.4-54.9), compared with patients with lower (worse) WRS (34.7, 95% CI, 24.3-45.1). However, among patients with worse mental health, there was no association between standard static Inner EAR scores and WRS. In contrast, adaptive Inner EAR mean scores were significantly higher for those with better WRS, regardless of mental health status. Thus, effect modification was observed in standard static assessments, whereas adaptive testing remained durably associated with audiometry, regardless of mental health. Psychological status was an effect modifier of the association between standard Inner EAR scale scores and audiometry, with a positive association observed only in those with better mental health. Adaptive testing scores, however, remained significantly associated with audiometry, even when mental status was worse. Adaptive testing may stabilize the association between subjective and objective hearing outcomes.

Application Progress of Objective Audiological Detection Techniques in Forensic Clinical Medicine.

The qualitative, quantitative, and localization analysis of hearing loss is one of the important contents of forensic clinical research and identification. Pure-tone audiometry is the "gold standard" for hearing loss assessment, but it is affected by the subjective cooperation of the assessed person. Due to the complexity of the auditory pathway and the diversity of hearing loss, the assessment of hearing loss requires the combination of various subjective and objective audiometric techniques, along with comprehensive evaluation based on the case situation, clinical symptoms, and other examinations to ensure the scientificity, accuracy and reliability of forensic hearing impairment assessment. Objective audiometry includes acoustic impedance, otoacoustic emission, and various auditory evoked potentials. The frequency-specific auditory brainstem response (ABR), 40 Hz auditory event related potential, and auditory steady-state response are commonly used for objective hearing threshold assessment. The combined application of acoustic impedance, otoacoustic emission and ABR can be used to locate hearing loss and determine whether it is located in the middle ear, cochlea, or posterior cochlea. This article reviews the application value of objective audiometry techniques in hearing threshold assessment and hearing loss localization, aiming to provide reference for forensic identification of hearing loss.

Neuropsychiatric Symptoms and Hearing Loss in Dementia: Unmet Need and Opportunity for Intervention

Hearing loss is one of the most common comorbidities among persons with dementia, with prevalence of 60->90%. Most go untreated and disparities exist. However, sensory impairment may influence the health of individuals and care partners. We will share findings from a clinic-based cohort of persons with dementia (n=101). Controlling for demographic and clinical factors, we found that every 10 decibel increase in hearing loss was associated with nearly an additional neuropsychiatric symptom (b = 0.7 per 10 dB; p = 0.01) and 1.3-point increase in severity (b = 1.3 per 10 dB; p = 0.04). These findings provide the first estimates that utilize objective audiometry. Furthermore, hearing aid use appeared to be protective. Hearing care may represent an additional, but underutilized, non-pharmacological intervention. We will discuss these findings in the context of the epidemiology of hearing loss in dementia and highlight new opportunities for managing hearing loss through community-based approaches.

Nueva versión en Windows del sistema AUDIX para la evaluación objetiva de la audición

El presente trabajo describe una nueva versión del sistema AUDIX, diseñada como una estación de trabajo informatizada, para la audiometría objetiva y subjetiva. El sistema, esta integrado por un ordenador (PC) con una serie de programas de cómputo (“software”) el cual se conecta mediante una interfaz universal (universal serial bus USB) con un bloque electrónico especializado (“hardware”). El bloque electrónico tiene dos amplificadores bioeléctricos y un estimulador acústico digital totalmente programable con dos canales independientes. Esto permite generar de manera simultánea por ambos oídos, estímulos complejos diferentes (mezcla de tonos modulados en amplitud). Los estímulos acústicos pueden ser presentados a través de audiófonos (suprauriculares o de inserción), vibrador óseo y/o altavoces. El software programado sobre una plataforma Windows, tiene 5 módulos diferentes para la adquisición y análisis de PEA transientes y de estado estable, audiometría conductual, administración de base de datos y calibración. La base de datos del sistema permite almacenar, borrar, extraer, crear y realizar copias de respaldo. Durante la adquisición de los PEA se utilizan diferentes métodos estadísticos como indicadores para la detección objetiva de las respuestas. Puede visualizarse en forma concurrente la actividad bioeléctrica de base (monitoreo de EEG) y el resultado de la promediación (PEA). Los resultados del examen electroaudiométrico son analizados fuera de línea de una manera flexible, generándose múltiples reportes gráficos y permitiendo la comparación automática con datos normativos. En el caso de los PEAee los resultados pueden ser presentados en el formato estándar de un audiograma convencional utilizando diferentes escalas (dB: HL, SPL, nHL). El sistema AUDIX ha sido validado ampliamente en la práctica clínica resultando de utilidad para la detección temprana de las pérdidas auditivas y la caracterización precisa de la audición en toda la gama de frecuencias audibles.

Exposure to exhaust fume at work is associated with hearing impairment

BACKGROUND AND AIM: To determine whether hearing impairment, defined by using objective audiometry, is associated with exhaust fume exposure at work. METHODS: Study participants are US adults aged 18 years or older (N = 3,867) who participated in the National Health and Nutrition Examination Survey (NHANES), 2007-2012, a nationally representative sample. Hearing ability was defined according to a speech‐frequency pure tone average of thresholds at 0.5, 1, 2, and 4 kHz in the better‐hearing ear. Thresholds of hearing impairment severity were based on American Speech‐Language Hearing Association guidelines (normal hearing 25.0 dB, mild to profound impairment ≥25.0). RESULTS:After adjusting for sex, BMI, income, education level, smoking status, multivariate odds ratios (ORs) for hearing impairment were 1.521 (95%CI, 1.042 - 2.221) comparing normal hearing for 65 years or older CONCLUSIONS:Exposure to exhaust fume at work were significantly associated with hearing impairment for 65 years or older. KEYWORDS: Exhaust fume, Exhaust gas, Hearing impairment

EEG-based diagnostics of the auditory system using cochlear implant electrodes as sensors

The cochlear implant is one of the most successful medical prostheses, allowing deaf and severely hearing-impaired persons to hear again by electrically stimulating the auditory nerve. A trained audiologist adjusts the stimulation settings for good speech understanding, known as “fitting” the implant. This process is based on subjective feedback from the user, making it time-consuming and challenging, especially in paediatric or communication-impaired populations. Furthermore, fittings only happen during infrequent sessions at a clinic, and therefore cannot take into account variable factors that affect the user’s hearing, such as physiological changes and different listening environments. Objective audiometry, in which brain responses evoked by auditory stimulation are collected and analysed, removes the need for active patient participation. However, recording of brain responses still requires expensive equipment that is cumbersome to use. An elegant solution is to record the neural signals using the implant itself. We demonstrate for the first time the recording of continuous electroencephalographic (EEG) signals from the implanted intracochlear electrode array in human subjects, using auditory evoked potentials originating from different brain regions. This was done using a temporary recording set-up with a percutaneous connector used for research purposes. Furthermore, we show that the response morphologies and amplitudes depend crucially on the recording electrode configuration. The integration of an EEG system into cochlear implants paves the way towards chronic neuro-monitoring of hearing-impaired patients in their everyday environment, and neuro-steered hearing prostheses, which can autonomously adjust their output based on neural feedback.

EXPLORATION OF MOBILE USERS WITH QUESTIONNAIRE METHOD AND OBJECTIVE AUDIOMETRY (OTOACOUSTIC EMISSION)

Background: The main purpose of study was to assess the impact of using mobile phones among young Ukrainians (age 17-25) on auditory system. We conducted a study using anonymous questionnaires and with using a method of objective audiometry (otoacoustic emission). Finally, we compared our results with results of studies which were conducted in Sweden and Finland. Those studies were first among all the others with assessment of association between amount of mobile phone use and frequency of headache, tinnitus or hearing loss at 4-year follow-up. Methods: The participants were chosen among volunteers (n=251). All of them received anonymous questionnaires. We made stratified sample by age, sex, type of phone used, duration of phone calls, using of headphones during calls, symptoms appearing after using cell phone (headache, tinnitus, hearing loss). Results: The age of respondents was 17-25 years (32,3% - 22 years, 13,1% - 19 years, 12,4% - 20 years, 10,8% - 23 years., 8,4% - 21 years., 8% - 18 years, 7,6% - 17 years, 2,8% - 24р., 2,8% - 25 years). Due to this data the median age of participants was 22 years. Sex: female – 74.3%, male – 25.7%. Most of participants were using mobile phones (99.2%). 51.8% of respondents were always using headphones during phone calls, 8.8% - never used headphones during phone calls, 39,4% - were rarely using headphones during phone calls. We assess the association between mobile phone use and appearing symptoms after phone calls. 3.6% of respondents reported a headache after phone calls, 96.4% were free of this symptom after phone calls. 58.2% reported headache at least once a week, 41.8% - were free of this symptom. 42.2% of respondents reported tinnitus: 1.6% reported tinnitus every day, 4.8% once in 2-3 days, 35.9% reported this symptom rarely (less than once a week). 57.8% of respondents were free of tinnitus. 21.5% of respondents reported hearing loss, 78.5% were free of hearing loss. Most of respondents associate headache with fatigue, sleep deprivation, stress, weather change, sleep disorders, arterial hypertension, hunger, frequent phone calls. Respondents who complained of hearing loss were offered to pass objective audiometry (optoacoustic emission).6 respondents took part in this examination. In 85 ears of respondents (71%) who complained of hearing loss it occurs on 8000 Hz. In 95 ears of respondents (79%) who complained of hearing loss it occurs on 5714 Hz. Pearson correlation coefficient between our results and results of Northern Europe studies was 0.935, suggesting a strong linear association.

Innovations in objective audiometry

Innovations in objective audiometry

Features of objective audiometry tests and their diagnostic value in the research of hearing in children

The article highlights the features of the conduct and interpretation of data on audiological tests at the children in order to identify the degree, type and level of damage of the auditory disorders. According to a survey of 121 children with a diagnosis of sensorineural hearing loss, it was confirmed that using a complex algorithm of audiological tests such as OAE, DPOAE, BERA and ASSR in hearing diagnosis of the children allows to obtain more accurate and detailed information and avoid possible errors in determining various forms of hearing disorders.

Hearing Loss, Loneliness, and Social Isolation: A Systematic Review.

Social isolation and loneliness are associated with increased mortality and higher health care spending in older adults. Hearing loss is a common condition in older adults and impairs communication and social interactions. The objective of this review is to summarize the current state of the literature exploring the association between hearing loss and social isolation and/or loneliness. PubMed, Embase, CINAHL Plus, PsycINFO, and the Cochrane Library. Articles were screened for inclusion by 2 independent reviewers, with a third reviewer for adjudication. English-language studies of older adults with hearing loss that used a validated measure of social isolation or loneliness were included. A modified Newcastle-Ottawa Scale was used to assess the quality of the studies included in the review. Of the 2495 identified studies, 14 were included in the review. Most of the studies (12/14) were cross-sectional. Despite the heterogeneity of assessment methods for hearing status (self-report or objective audiometry), loneliness, and social isolation, most multivariable-adjusted studies found that hearing loss was associated with higher risk of loneliness and social isolation. Several studies found an effect modification of gender such that among women, hearing loss was more strongly associated with loneliness and social isolation than among men. Our findings that hearing loss is associated with loneliness and social isolation have important implications for the cognitive and psychosocial health of older adults. Future studies should investigate whether treating hearing loss can decrease loneliness and social isolation in older adults.

Analysis of genotypes and hearing phenotypes of mutation infants with deafness

Objective:The aim of this study is to explore the genotype and hearing phenotype of deaf infants with mutation of GJB2 gene. Method:Subjects were 121 infants with GJB2 gene mutations who were treated in the Children's Hearing Diagnosis Center of Beijing Tongren hospital. All subjects were accepted to undertake the universal newborns hearing screening（UNHS） and series of objective audiometry, including auditory brainstem response, distortion product otoacoustic emission, auditory steady-state response and other audiological tests. All subjects were screened for nine pathogenic variants in four genes or all exons of the GJB2 gene, and then were diagnosed as infants with GJB2 gene mutations. Initially, analyzing their genotypes and hearing phenotypes generally. Then, the subjects were divided into two groups according to the genotypes: T/T group（truncated/truncated mutations, 89 cases） and T/NT group（truncated/non-truncated mutations, 32 cases）. Chi-square test was used to analyze the results of UNHS, hearing degree, audiogram patterns and symmetry/asymmetry of binaural hearing phenotype. Eventually, analyzing the results of UNHS. Result:The most common truncated mutation was c.235delC（64.88%, 157/242） and the most common non-truncated mutation was c.109G>A（11.16%, 27/242）. The homozygous mutation of c.235delC/c.235delC was the dominant in T/T group（38.84%, 47/121）, and the compound heterozygous mutation of c.235delC/c.109G>A was the dominant in T/NT group（18.18%, 22/121）. 81.82%（99/121） of subjects failed in UNHS, including 74.38%（90/121） with bilateral reference, 7.44%（9/121） with a single pass. The refer rate of UNHS of group T/T and T/NT were 86.52%（77/89） and 68.75%, respectively. There was a statistically significant difference between the two groups（P<0.05）. 85.95%（104/121） of subjects were diagnosed as hearing loss and 14.05%（17/121） of subjects were diagnosed as normal hearing. The degree of hearing loss: profound, severe, moderate and mild were 31.40%（38/121）, 19.01%（23/121）, 24.79%（30/121） and 10.74%（13/121）, respectively. There was no subjects with normal hearing in T/T group and individuals with severe and profound hearing loss accounted for the highest proportion（65.17%, 58/89）, while in T/NT group, normal hearing accounted for 53.13%（17/32） and mild and moderate hearing loss accounted for the highest proportion（37.5%, 12/32）. There was statistically significant difference between the two groups（P<0.05）. Of 104 patients（208 ears） with hearing loss, the audiogram patterns: flat, descending, ascending, residual, Valley and other types were 49.03%（102/208）, 12.02%（25/208）, 8.65%（18/208）, 7.69%（16/204）, 3.36%（7/204） and 19.23%（40/204）, respectively. The two most common types in T/T group were flat（47.19%, 84/178） and other types（20.22%, 36/178）, while in T/NT group were flat（60.00%, 18/30） and ascending（20.00%, 6/30）. There was statistically significant difference between the two groups（P<0.05）. There were 50 cases（48.07%） with symmetrical hearing phenotype and 54 cases（51.93%） with asymmetrical hearing phenotype. Asymmetry was predominant in T/T group（53.93%, 48/89）, and symmetry was predominant in T/NT group（60.00%, 9/15）. There was no statistically significant difference between the two groups（P>0.05）. Conclusion:In this study, c.235delC/c.235delC homozygous mutation was dominant in T/T group and c.235delC/c.109G>A heterozygous mutation was dominant in T/NT Group. The hearing phenotypes in T/T group were mostly bilateral asymmetric severe hearing loss, and those in T/NT Group were bilateral symmetric mild to moderate hearing loss, special attention should be paid to the audiological characteristics of different genotypes.

Characteristics of auditory brainstom response and auditory steady state evoked responses in noise-induced hearing loss population

Objective: To explore the characteristics of auditory steady state evoked responses (ASSR) and auditory brainstem response (ABR) in noise-induced hearing loss population and the relationship between the response threshold of corresponding frequency and pure tone audiometry (PTA) . Methods: Noise-induced hearing loss patients who completed subjective and objective audiometry in our hospital from October 2014 to October 2018 were collected. The results of PTA, ABR, ASSR and the correlation between subjective and objective audiometry were discussed. Results: A total of 381 ears of 193 patients were enrolled. The difference of 0.5, 1.0, 2.0 and 4.0 kHz between ASSR threshold and PTA was 5.9, 6.9, 11.8 and 1.8 dB, respectively. The correlation coefficients were 0.638, 0.680, 0.657 and 0.608. The difference of 1.0, 2.0, 3.0 and 4.0 kHz between ABR threshold and PTA was 44.2, 35.0, 19.0 and 2.0 dB. With the increase of frequency, the threshold difference between ABRt V wave and PTA decreased gradually. Conclusion: ASSR and ABR response thresholds are valuable in subjective assessment on noise-induced hearing loss. The thresholds of ASSR and ABR at 4 kHz are close to those of PTA.

Assessment of Objective Audiometry to Predict Subjective Satisfaction in Patients With Hearing Aids.

ObjectivesTo investigate the correlation of objective audiometry with user satisfaction as measured with the questionnaire scores.MethodsTwenty patients with hearing loss, who agreed to wear a hearing aid and were referred for hearing aid fitting, were included in this prospective clinical study. All patients used the in-the-canal type of Wide7 hearing aid provided by BSL Co., Ltd. We performed the Korean version of the Hearing Handicap Inventory for the Elderly (K-HHIE) and the International Outcome Inventory for Hearing Aids (K-IOI-HA) before and 1, 3, and 6 months after wearing the hearing aid. We also performed pure tone audiometry (PTA), speech audiometry (SA), functional gain (FG), hearing in noise test (HINT), and central auditory processing disorder tests, such as frequency pattern test (CA-f), duration pattern test (CA-d), and dichotic test (CA-Di). Patients were divided into two groups (group A-HHIE, improved; group B-HHIE, same or worse) by comparing the score of K-HHIE before and 6 months after wearing the hearing aid. In the 6-month K-IOI-HA questionnaire, 21 points were considered as the average score. Based on this, we further divided patients into two groups (group A-IOI, >21 points; group B-IOI, ≤21 points).ResultsGroup A-HHIE included six patients and group B-HHIE included 14 patients. In PTA, SA, HINT, CA-d, and CA-Di, group A-HHIE showed higher improvements than group B-HHIE, which were not statistically significant. Group A-IOI included 12 patients and group B-IOI included eight patients. No statistically significant difference was noted in the improvement of audiometric results over a period of 6 months after wearing the hearing aid between groups A-IOI and B-IOI.ConclusionThere were no significant and consistent audiometric results to reflect patient’s satisfaction with the hearing aid. Therefore, when analyzing the hearing aid-fitting outcome, both the objective audiometric tests and subjective questionnaire should be performed together for validating hearing aid performance.

Issues of simulation, aggravation and dissimulation in expert questions for hearing disorders

Those who are working in the conditions accompanied with industrial noise exceeding normal rates and who receive irreversible decrease in hearing of sensorineural nature, proceeding from the existing legislation, have to be exposed to expert assessment of the audiologist-otorhinolaryngologist, for the purpose of examination of professional suitability. Medical experts should face such phenomena as aggravation and simulation of hearing loss which exposure and also definition of a true threshold for sound perception, nature of the available violations, is their paramount task.The tests serving for simulation identification are carried out with application of subjective audiometry, i.e. with active participation of the examined person or by means of the objective audiometry excluding participation of the patient. Observation of the patient behavior, analysis of the anamnestic data, carrying out the acumetry and tuning testing, subjective and objective audiometry and also comparison of the obtained data allows to make expert assessment of a clinical case. The objective audiometry (OET, KSVP, ECOG, acoustic impedancemetry) is crucial in case of the doubts arising after carrying out a subjective audiometric research.

Auditory Steady-State Responses Across Chirp Repetition Rates For Ear-EEG And Scalp EEG.

Measurement of auditory steady-state responses (ASSR) using ear-EEG potentially enables objective audiometry out of the clinic in the everyday life of hearing aid users. As ear-EEG are measured from electrodes placed within the ear, electrode distances are inherently small and consequently the potential differences, and thereby signal amplitudes, are also small. Because the detection of the ASSR is based on the signalto-noise ratio (SNR), it is of fundamental interest to know the inherent SNR of the ASSR as a function of the stimulus repetition rate. In this study, ASSRs were recorded using both scalp and ear-EEG in response to broadband chirp stimuli with repetition rates from 20 to 95 Hz. The results showed that in general ear-EEG and scalp EEG SNR was on par across repetition rates; an exception to this was at rates around 40 Hz where the SNR was significantly lower for ear-EEG as compared to scalp EEG. For ear-EEG, the ASSR was relatively constant across repetition rates, whereas the noise showed a 1/f characteristic. In consequence, there was a tendency to increased SNR as a function of repetition rate. This suggests that use of relatively high repetition rates may be beneficial in earEEG applications.

Objective audiometry and clinical application

Subjective and objective hearing tests are used for evaluation of hearing impairments. Objective methods include impedance measurement with tympanometry and stapedius reflex measurement, otoacoustic emissions (OAE), and auditory evoked potentials (AEP). Combined with statistical analysis, the introduction of auditory steady state responses (ASSR) has enabled objective hearing tests in newborn hearing screening and automated hearing threshold assessment. The type and degree of hearing loss can be determined using the abovementioned methods. Precise interpretation of the test results is helpful to distinguish an auditory synaptopathy/neuropathy from classical sensorineural hearing loss.

Pure-tone Audiometer

The research focuses on a pure-tone audiometer designing. The relevance of the study is proved by high incidence of an auditory analyser in older people and children. At first, the article provides information about subjective and objective audiometry methods. Secondly, we offer block-diagram and basic-circuit arrangement of device. We decided to base on STM32F407VG microcontroller and use digital pot in the function of attenuator. Third, we implemented microcontroller and PC connection. C programming language is used for microcontroller’s program and PC’s interface. Fourthly, we created the pure-tone audiometer prototype. In the future, we will implement the objective method ASSR in addition to pure-tone audiometry.

Childhood psychogenic hearing loss: Identification and diagnosis

Psychogenic hearing loss, formerly known as functional or non-organic hearing loss, is a classic cause of consultation in infantile audiology. Risk factors include female gender, and age 8 or 12 years. Onset is relatively sudden, without impact on schooling or voice quality. Audiometric signs comprise non-superimposable audiometric thresholds (variable audiometric results), bilaterality, flat mean audiometric curve, and discrepancy between pure-tone and speech audiometry. The child needs reassuring during audiometric examination: attention–diversion techniques may be effective. Objective audiometry allows positive diagnosis, followed by rehabilitation and psychological care.

Ups and Downs in 75 Years of Electrocochleography.

Before 1964, electrocochleography (ECochG) was a surgical procedure carried out in the operating theatre. Currently, the newest application is also an intra-operative one, often carried out in conjunction with cochlear implant surgery. Starting in 1967, the recording methods became either minimal- or not-invasive, i.e., trans-tympanic (TT) or extra tympanic (ET), and included extensive studies of the arguments pro and con. I will review several valuable applications of ECochG, from a historical point of view, but covering all 75 years if applicable. The main topics will be: (1) comparing human and animal cochlear electrophysiology; (2) the use in objective audiometry involving tone pip stimulation—currently mostly pre cochlear implantation but otherwise replaced by auditory brainstem response (ABR) recordings; (3) attempts to diagnose Ménière’s disease and the role of the summating potential (SP); (4) early use in diagnosing vestibular schwannomas—now taken over by ABR screening and MRI confirmation; (5) relating human electrophysiology to the effects of genes as in auditory neuropathy; and (6) intracochlear recording using the cochlear implant electrodes. The last two applications are the most recently added ones. The “historical aspects” of this review article will highlight the founding years prior to 1980 when relevant. A survey of articles on Pubmed shows several ups and downs in the clinical interest as reflected in the publication counts over the last 75 years.

REMOVED: Extraction of distortion-product otoacoustic emission source components and its relevance for objective audiometry

Distortion-product otoacoustic emissions (DPOAEs) arise as byproduct of nonlinear amplification in the cochlea in response to two stimulus tones of different frequencies. They are assumed to comprise mainly two components, a nonlinear-distortion component and a coherent-reflection component, which may cause wave interference in recordings with conventional, continuous stimulus tones, hampering the accuracy of DPOAEs when evaluating cochlear function. Here, DPOAEs are recorded with short stimulus pulses enabling the separation of the two source components in the time domain. Comparison with conventional stimulation endorses the importance of reliable source separation when using DPOAEs in clinical audiometry or research.