New Perspectives in Hearing Assessment: Part 2. Application of Distortion Product Otoacoustic Emissions in the Diagnosis of Hearing Loss - Step A

2MEDINCUS - DOI: 10.5281/ZENODO.16905033 - VOL.31, OCTOBER/2025 This is the second in a series of newsletters that focus on the importance of evidence-based hearing assessment in making an accurate audiologic diagnosis. Anaccuratediagnosisofhearingdysfunctionisthefirststepindevelopingan effective plan for managing hearing loss. The series, titled “New Perspectives in Hearing Assessment,” includes newsletters that review the main testing procedures for diagnostic evaluation of hearing function in children and adults. A recurring theme in the series is the application of the crosscheck principle. We highlight the unique characteristics and practical advantages of each auditory procedure, as well as the pattern of test results that guide us to a clear and reliable audiologic diagnosis. MilaineDominiciSanfins,PiotrHenrykSkarzynskiandJamesWHallIII NEW PERSPECTIVES IN HEARING ASSESSMENT: PART 2.APPLICATION OF DISTORTION PRODUCT OTOACOUSTIC EMISSIONS IN THE DIAGNOSIS OF HEARING LOSS - STEP A (ANATOMICAL REVIEW AND CLINICAL ADVANTAGES) 3 MEDINCUS - DOI: 10.5281/ZENODO.16905033 - VOL.31, OCTOBER/2025 INTRODUCTION Since David Kemp described “stimulated acoustic emissions from within the human auditory system” in 1978 (Kemp, 1978), otoacoustic emissions (OAEs) have evolved into a valuable clinical technique for hearing screening and diagnosis of auditory dysfunction. OAEs offer a relatively simple, quick, and inexpensive approach for early detection of hearing loss in varied populations, including: newborn infants,  preschoolandschoolchildren,  adultsatriskfornoise-and/ormusic-inducedhearingimpairment (Dhar & Hall, 2018; Hall & Kleindienst Robler, 2024; Joint Committee on Infant Hearing, 2019). OAEs also play an important and rather unique role in the test battery for diagnosis of hearing loss and related hearing disorders in patients across the lifespan (Hall, 2021)., e.g.:  tinnitus,  disordersofdecreasedsoundtolerance,  auditoryprocessingdisorders Evidence-based clinical practice guidelines provide detailed recommendations for OAE measurement, analysis, and clinical application (British Society of Audiology, 2023). 4MEDINCUS - DOI: 10.5281/ZENODO.16905033 - VOL.31, OCTOBER/2025  Interestedreaderswillhavenoproblemfindingresourcesandreferenceon OAEs, including detailed discussions of relevant auditory anatomy and physiology, mechanisms, distinctions between transient evoked OAEs (TEOAEs) vs. distortion product OAEs (DPOAEs), and research-based reviews of clinical applications of OAEs in a wide range of auditory disorders and otologic diseases (e.g., Dhar & Hall,2018;Hall&Swanepoel,2010).Inaddition.thescientificliteraturecontains over 6500 peer reviewed publications on OAEs (e.g., https://pubmed.ncbi.nlm. nih.gov/?term=otoacoustic+emissions. This brief paper presents practical information on clinical measurement and analysis of DPOAEs in the diagnosis of auditory dysfunction. The discussion focuses on DPOAEs, not TEOAEs. Also, we don’t address the well-documented application of OAEs in hearing screening nor the varied contributions of information from OAE measure in basic investigations of cochlear physiology and pathophysiology. Our overall goal is to encourage audiologists to take full advantage of DPOAEs as a clinical tool, and to provide some practical tips for the most effective clinical application of DPOAEs in pediatric and adult patient populations. 5 MEDINCUS - DOI: 10.5281/ZENODO.16905033 - VOL.31, OCTOBER/2025 BRIEF REVIEW OF ANATOMIC STRUCTURES INVOLVED IN DPOAE MEASUREMENT  Agoodunderstandingoftheanatomicand physiologicunderpinningsofOAEgenerationand measurementisessentialforrecording,analyzing,and interpretingfindingsintheclinicalsetting.Asillustrated schematicallyinFigure1,fourgeneralregionsof auditorysystemanatomyareinvolvedinthegeneration andmeasurementofOAEs. Figure1. Schematic diagram of the four auditory structures or regions involved in the measurement of DPOAEs. Source: Dhar S & Hall JW III (2018). Otoacoustic Emissions: Principles, Procedures, and Protocols. San Diego: Plural Publishing Sanfins,SkarzynskiandHall,2025 6MEDINCUS - DOI: 10.5281/ZENODO.16905033 - VOL.31, OCTOBER/2025 TheEXTERNALEARCANAL plays a crucial role in stimulus delivery and OAE recording. variety of pathologic and non-pathologic conditions of the external ear have serious ramificationsonOAEmeasurements. TheMIDDLEEAR (tympanic membrane and ossicles) is a vital link in OAE measurement. Stimuli used to elicit OAEs are transmitted to the cochlea via the middle ear. In addition, OAEs generated in the cochlea travel outward through the middle ear on the way to the external ear canal. The source of OAE activity is found within the COCHLEA.Specifically,OAEs reflectouterhaircellactivityandfunctionalintegrityofallcomponentsof outer hair cells is essential for generation of OAEs. Other structures in and related to the cochlea also play a crucial role in the generation of normal OAEs, including the blood vessels serving the organ of Corti, the stria vascularis, and the reticular formation. Finally, activation of the EFFERENT AUDITORY SYSTEM, particularly the olivocochlearbundle,mayalsoinfluenceOAErecordings. Readers are referred to Chapter 2 of Dhar & Hall (2018) for a more detailed review of the anatomy and physiology underlying OAE measurement. 1 2 3 4 7 Clinical reports describing the diagnostic value of DPOAEs in frequency-specific assessment of hearing loss date back to the mid-1990s (e.g., Gorga et al, 1993; Hall, 2000; Hornsby, Kelly & Hall, 1996; Lonsbury-Martin, Martin, McCoy & Whitehead, 1994). During this exciting era in the evolution of OAEs, most manufacturers of audiology instrumentation introduced the first generation of clinical DPOAE devices. Research since then has clearly demonstrated the diagnosticsensitivityandspecificityofDPOAEsforadiversecollectionof etiologies affecting outer hair cell function, such as: (for reviews see Dhar & Hall, 2018; Hall, 2021). perinataldiseases, exposure to damaging levels of noise or music or ototoxicdrugs, otologicdiseases(e.g.,Meniere’s disease, autoimmunedisease), age-related hearing loss secondary to comorbid conditions like diabetes andcardiovasculardisease DISTINCTIONS IN APPLICATION OF DPOAES FOR DETECTION VERSUS DIAGNOSIS OF HEARING LOSS MEDINCUS - DOI: 10.5281/ZENODO.16905033 - VOL.31, OCTOBER/2025 8  Longstanding basic and clinical research findings confirm that DPOAEs are a highly sensitive and frequency specific measure of outer hair cell function, with diagnostic qualities unmatched by any other clinical procedure. As a diagnostic measure, DPOAEsprovidevitalinformationonthe statusofouterhaircells.Abnormalities in outer hair cell function may also occur secondary to pathophysiology affecting other cochlear structures, particularly the stria vascularis. OAEsdonotshedanylightoninnerhaircellfunction. This limitation has minimal impact on the clinical usefulness of OAEs because outer hair cell dysfunction or damage is an invariable feature of many otologic disorders or diseases associated with a wide assortment of cochlear abnormalities. As a result, the diagnostic value of DPOAEs extends to essentially all etiologies of sensory hearing loss. There is compelling longstanding research evidence in support of the value of DPOAEs in diagnosis of auditory function. Nonetheless, audiologists often recordandanalyzeDPOAEsindiagnosticassessments with the same simple dichotomous “pass” vs. “fail” or “present” versus “absent” approach that is used in hearing screening. MEDINCUS - DOI: 10.5281/ZENODO.16905033 - VOL.31, OCTOBER/2025  Table 1. Distinctions in measurement and analysis of distortion product otoacoustic emissions (DPOAEs) in detection of hearing loss (hearing screening) versus the diagnosis of hearing loss (comprehensive audiologic assessment). Refer also to Figures 1. HEARINGSCREENING DIAGNOSISOFHEARINGLOSS DPOAE Measurement Stimulus Frequency Range Test stimuli within a limited frequencyrange,e.g.,2000Hz to5000Hz Test stimuli for a wide frequency range,e.g.500Hzto>8000Hz Number ofStimulus Frequencies •Stimuli for a limited number of frequencies, e.g., two or three or frequencies •Few frequencies per octave, e.g., 1 or 2 •Relatively large number of stimulus frequencies,e.g.,>20frequencies •Numerous frequencies per octave, e.g.,>4 Replication ofRecordings DPOAEs are not replicated (plotted as a single DPgram) DPOAEs are replicated and plotted as two superimposed DPgrams Stimulus Intensity Stimuli are presented at a singlefixedintensitylevel(e.g., L1 = 65 dB SPL; L2 = 55 dB SPL) Stimuli may be presented at multiple higher and lower intensity levels DPOAEAnalysis 9 MEDINCUS - DOI: 10.5281/ZENODO.16905033 - VOL.31, OCTOBER/2025 Table 1. delineates distinctions between the application of DPOAEs in hearing screening versus diagnostic assessment. We’ll offer at this point several hypothetical clinical scenarios to clarify the obvious limitations resulting from reliance on a simple DPOAE screening protocol when the clinical goal is comprehensive diagnostic assessment. 16 references consulted: British Society of Audiology (2023). Recommended Procedure: Clinical Application of Otoacoustic Emissions (OAEs) in Children and Adults. https://www.thebsa.org.uk/wp-content/ uploads/2023/10/OD104-120-Recommended-Procedure-ClinicalApplication-of-Otoacoustic-Emissions-OAEs.docx.pdf Sanfins Dominici M, Skarzynski P & Hall JW III (2024). New Perspectives in Hearing Assessment: Part 1. Application of value-added tests in the diagnosis of hearing loss. Medincus, 13 (February), 1-18. Canete OM, El-Haj-Ali M, Fereczkowski M (2024). Comparison of two devices for measurement of distortion product otoacoustic emissions in normal hearing adults. Journal of Audiology and Otology, 28, 146-152 Dhar S & Hall JW III (2018). Otoacoustic emissions: Principles, Procedures, and Protocols. San Diego: Plural Publishing. Sanfins MD, Bertazolli LF, Skarzynski PH, Skarzynska MB, Donadon C & Colella-Santos MF (2020). Otoacoustic Emissions in Children with Long-Term Middle Ear Disease. Life (Basel, Switzerland), 10(11), 287. https://doi.org/10.3390/life10110287 Gellrick D, Groger M, Echternach M, Eder K & Huber P (2024). Neonatal hearing screening – does failure in TEOAE screening matter when AABR test is passed? European Archives of OtoRhino-Laryngology. 281, 1273-1283 Gorga MP, Neely ST, Bergman B, Beauchaine KL, Kaminski JR, Peters J & Jesteadt W.J (1993). Otoacoustic emissions from normal-hearing and hearing-impaired subjects: distortion produce responses. Journal of the Acoustical Society of America, 93 (4), 2050-2060 Hall JW III, Chase PA, Baer JE & Schwaber MK (1994). Clinical application of otoacoustic emissions: What do we know about factors influencing measurement and analysis? Otolaryngology Head and Neck Surgery, 110, 22-38 Hall JW III (2000). Handbook of Otoacoustic Emissions. San Diego: Singular Publishing Group Sanches AB, Sanfins MD, Skarzynski PH, Skarżyńska MB, Penatti HC, Donadon C, Souza IP, Silva IVD & Colella-Santos MF (2024). Wideband Tympanometry and Pressurized Otoacoustic Emissions in Children with Surgical Excision of Palatine and/ or Pharyngeal Tonsils. Brain sciences, 14(6), 598. https://doi. org/10.3390/brainsci14060598 Hall JW III, Smith S, Popelka G (2004). Newborn hearing screening with combined otoacoustic emissions and auditory brainstem response. Journal of American Academy of Audiology, 15, 414-425 Hall JW III & Swanepoel D (2010). Objective Assessment of Hearing Loss. San Diego: Plural Publishing Hall JW III (2014) Introduction to Audiology Today. Boston: Pearson Educational Hall JW III (2016). Objective assessment of infant hearing: Essential for early intervention. Journal of Hearing Science, 6 (2), 1-17 Hall JW III (2016). The crosscheck principle in pediatric audiology: A 40-year perspective. Journal of Audiology and Otology, 20 (2), 1-9 Hall JW III (2021). Promoting healthy hearing over the lifespan. Auditory & Vestibular Research, 30, 74-94 Hall JW III & Kleindienst Robler S (2024). A new strategy for hearing screening of preschool and school-age children. AudiologyOnline, Article 29069. Available at www. audiologyonline.com Hornsby B, Kelly T, Hall JW III (1996). Normative data for five FDA-approved commercially available distortion product systems. The Hearing Journal 49, 3946 Jerger JF & Hayes D (1976). The cross-check principle in pediatric audiometry. Archives of Otolaryngology, 102, 614-620 Joint Committee on Infant Hearing (2019). Year 2019 Position Statement: Principles and Guidelines for Early Hearing Detection and Intervention Programs. The Journal of Early Hearing Detection and Intervention, 4 (9), 1-44 Kemp DT (1978). Stimulated acoustic emissions from within the human auditory system. The Journal of the Acoustical Society of America, 64, 1386-1391 Lonsbury-Martin, B.L., Martin, G.K., McCoy, M.J. & Whitehead, M. (1994). Otoacoustic emissions testing in young children: middle ear influences. American Journal of Otology, 15 (supplement 1), 13-20 Mertes IB & Marquess A (2023). A survey of U.S. audiologists’ usage and attitudes toward otoacoustic emissions. American Journal of Audiology, 32, 417-431. Sanfins Dominici M, Skarzynski P & Hall JW III (2024). New Perspectives in Hearing Assessment: Part 1. Application of value-added tests in the diagnosis of hearing loss. Medincus, 13 (February), 1-18. Windmill IM & Freeman BA (2019). Medicare, hearing care and audiology. Audiology Today, 31 (March), 17 – 26. Novelli CVL, Sanfins MD, Skarżyński PH, Skarżyńska MB, Diniz-Hein TA & Colella-Santos MF (2024). Neonatal Hearing Screening Using Wideband Absorbance and Otoacoustic Emissions Measured Under Ambient and Pressurized Conditions. Children, 11(11), 1290. https://doi.org/10.3390/ children11111290 01. 02. 03. 04. 05. 06. 07. 08. 09. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. MEDINCUS - DOI: 10.5281/ZENODO.16905033 - VOL.31, OCTOBER/2025 17 MEDINCUS - DOI: 10.5281/ZENODO.16905033 - VOL.31, OCTOBER/2025 Authors - Professor, ENT, Master and Doctorate by Medical University of Warsaw; - Research, didactic, clinical, and organizational work in World Hearing Center of Institute of Physiology and Pathology of Hearing, Institute of Sensory Organs and Medical University of Warsaw; - Specialist in ENT, pediatric ENT, audiology and phoniatrics, and public health. Participated in the 3rd Stakeholders Consultation meeting during which the World Hearing Forum of WHO was announced; - Member of the Roster of Experts on Digital Health of WHO, Vice-President and Institutional Representative of ISfTeH; - President-elect of International Advisory Board of AAOHNS, member of Congress and Meeting Department of EAONO, Regional Representative of Europe of ISA, VicePresident of HearRing Group, Auditor of EFAS, member of the Facial Nerve Stimulation Steering PROF.DR.PIOTRHENRYKSKARZYNSKI Committee; - Board Secretary of the Polish Society of Otorhinolaryngologists, Phoniatrists and Audiologists. Member of Hearing Committee (2018–19); - Goodwill Ambassador representing Poland at the AAOHNSF 2021 Annual Meeting & OTO Experience, and since 2021 a member of Implantable Hearing Devices Committee and Otology & Neurotology Education Committee of AAOHNS; - Consultant Committee of International Experts of CPAM-VBMS (by special invitation), honorary member of ORL Danube Society, and honorary member of Société Française d’Oto-Rhino-Laryngologie; - Member of the Council of National Science Center; - Expert and member of numerous national organizations. - Professor of the Audiology da Universidade Federal de São Paulo (UNIFESP); - Research group member, Institute of Physiology and Pathology of Hearing, Kajetany, Poland. - Professor of the post-graduate program in Clinical Audiology at the Albert Einstein Israelite Institute of research and teaching; - Postdoc at the World Hearing Center, Warsaw, Poland; - Sandwich Doctorate by School of Medical Sciences, Universidade Estadual de Campinas (FCM-UNICAMP) and by Università degli Studi di Ferrara/Italy; - Specialist in Audiology by Federal Council of Speech Therapy and Audiology; PROF.DR.MILAINEDOMINICISANFINS - Speech Therapist and Audiologist, Master by Medical School of University of São Paulo (FMUSP); - Member of the Teaching and Research Commission of the Brazilian Academy of Audiology (2024-2026); - Rapporteur of the Research Ethics Committee of the Federal University of São Paulo; - Reviewer of scientifi c articles in the area of Neuroaudiology, Neuroscience, Electrophysiology and Audiology; - Instagram @misanfi ns / email: msanfi [email protected]om.br and msanfi [email protected] 18 MEDINCUS - DOI: 10.5281/ZENODO.16905033 - VOL.31, OCTOBER/2025 Is an internationally recognized audiologist with more than 40-years of clinical, teaching, research, and administrative experience. He received his bachelor’s degree in biology from American International College, his master's degree in Speech Pathology from Northwestern University, and his Ph.D. in Audiology from Baylor College of Medicine under the direction of James Jerger. During his career, Dr. Hall has held clinical and academic audiology positions at major medical centers. A founder PROF.DR.JAMESHALLIII of the American Academy of Audiology, Dr. Hall has held numerous leadership roles in the organization. Dr. Hall is the author of over 200 peer-reviewed publications, invited articles, and book chapters, plus 12 textbooks. Dr. Hall now holds academic appointments as Professor (part-time) at Salus University and the University of Hawaii, a position as Extraordinary Professor at the University of Pretoria South Africa, along with other adjunct and visiting professor positions in the USA and abroad. 19 Quiz 1.Accordingtotheanatomicalreviewofthe text,whichofthefollowingstructuresisthe sourceofDistortionProductOtoacoustic Emissions(DPOAE)activity? A. The middle ear (tympanic membrane and ossicles). B. The cochlea. The cochlea. C. The efferent auditory system. D. The external auditory canal. 2.Accordingto'Table1'ofthetext,which ofthefollowingstatementscorrectly describesthecollectionofOAEsinthe contextofanaudiologicaldiagnosis, comparedtohearingscreening? A. Use of stimuli at a single fixed intensity level. B. Dichotomous analysis of the results, such as 'Approved' versus 'Failed'. C. Test stimuli for a wide range of frequencies (e.g., 500 Hz to > 8000 Hz). D. Test stimuli in a limited frequency range (e.g., 2000 Hz to 5000 Hz). 3.Accordingtothetext,whatisaclinical limitationofOtoacousticEmissions(OAE)? Accordingtothetext,whatisaclinical limitationofOtoacousticEmissions(OAE)? A. They do not clarify the function of the inner hair cells. B. The measurement of OAEs requires a sound-treated room. C. They do not provide information about the function of the outer hair cells. D. They depend on the patient's motivation to provide a behavioral response. 4.Whichofthefollowingoptionsis presentedinthetextasasignificant clinicaladvantageofOAEsinaudiological diagnosis?Whichofthefollowingoptions ispresentedinthetextasasignificant clinicaladvantageofOAEsinaudiological diagnosis? A. The analysis of the results is a manual and timeconsuming process. B. They depend on the patient's cognitive state, such as attention and memory. They depend on the patient's cognitive state, such as attention and memory. C. They require a long testing time (often more than 5 minutes per ear). D. They are a completely objective measure, not depending on a behavioral response from the patient. 5.Thecombinationofanormalaudiogram withabnormalOAEsisarelevantclinical finding.Thecombinationofanormal audiogramwithabnormalOAEsisa relevantclinicalfinding.Accordingtothe text,whatisthemostlikelyimplicationof thiscombinationofresults? A. Integrity of the outer hair cells and normal cochlear integrity. B. The presence of neural hearing loss, such as in auditory neuropathy spectrum disorder (ANSD). C. Cochlear dysfunction associated with risk factors such as noise exposure or ototoxic medications. D. The presence of a false hearing loss (simulation). Answers: 1B 2D 3A 4D 5C MEDINCUS - DOI: 10.5281/ZENODO.16905033 - VOL.31, OCTOBER/2025