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Update on Auditory Electrophysiology

Update on Auditory Electrophysiology. James W. Hall III, PhD Adjunct Professor Nova Southeastern University Salus University University of Florida Extraordinary Professor University of Pretoria South Africa jwhall3phd@gmail.com www.audiologyworld.net

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Update on Auditory Electrophysiology

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  1. Update on Auditory Electrophysiology James W. Hall III, PhD Adjunct Professor Nova Southeastern University Salus University University of Florida Extraordinary Professor University of Pretoria South Africa jwhall3phd@gmail.comwww.audiologyworld.net James W. Hall III Audiology Consulting, LLC

  2. Update on Auditory Electrophysiology • Introduction to auditory electrophysiology … 85-years of research and clinical application • Electrocochleography (ECochG) … It’s for much more than just the diagnosis of Meniere’s Disease • ABR … Over 4000 peer-reviewed publications in the past decade alone • ASSR … Filling an important niche in auditory assessment of children and adults • Cortical auditory evoked responses … Now we’re really assessing hearing • Summary, Questions & Answers

  3. Update on Auditory Electrophysiology: Objective Assessment from Cochlea to Cortex • Cortical auditory evoked responses • P300 response and other cognitive evoked responses • Auditory late response (ALR) • Auditory middle latency response (AMLR) • Auditory steady state response (ASSR) • Auditory brainstem response (ABR) • Electrocochleography (ECochG)

  4. Update on Auditory Electrophysiology: Behavioral Audiometry Isn’t Always Enough • Auditory electrophysiology is feasible in patients who cannot be assessed validly with behavioral techniques • Newborn and older infants • Difficult-to-test children • Sick patients • False and exaggerated hearing loss, e.g., • Pseudohypacusis • Functional hearing loss • Non-organic hearing loss • “Crocks”

  5. Update on Auditory Electrophysiology: Behavioral Audiometry Isn’t Always Enough • Auditory electrophysiology is feasible in sleeping and unconscious patients • Naturally sleeping children or adults • Children who are sedated or anesthetized for auditory assessment • Anesthetized patients undergoing surgery who require intra-operative neurophysiologic monitoring • Comatose head-injured patients who require intensive care unit monitoring • Automated auditory electrophysiology procedures can be performed by non-audiologic personnel for early newborn hearing screening (e.g., automated ABR)

  6. Update on Auditory Electrophysiology: Behavioral Audiometry Isn’t Always Enough (2) • Auditory electrophysiology has greater sensitivity to auditory function than behavioral audiometry (e.g., ABR in early identification of retrocochlear dysfunction) • Auditory electrophysiology has greater site specificity to auditory function than behavioral audiometry, e.g., • ECochG differentiates sites of dysfunction in auditory neuropathy spectrum disorder (ANSD) • ABR differentiates among cochlear, eighth nerve, and brainstem sites of dysfunction • Cortical auditory evoked responses specify site of dysfunction with central auditory nervous system

  7. Update on Auditory Electrophysiology • Introduction to auditory electrophysiology … 85-years of research and clinical application • Electrocochleography (ECochG) … It’s for much more than just the diagnosis of Meniere’s Disease • ABR … Over 4000 peer-reviewed publications in the past decade alone • ASSR … Filling an important niche in children and adults • Cortical auditory evoked responses … Now we’re really assessing hearing • Summary, Questions & Answers

  8. Original Description of Electrocochleography (ECochG) Wever EG and Bray CW. 1930. Action currents in the auditory nerve in response to acoustic stimulation. Proceedings of the National Acad of Science (USA) 16: 344-350. Wever EG and Bray CW. 1930. Auditory nerve impulses. Science 71: 215. E. Glen Weaver, Ph.D. (October 16, 1902 — September 4, 1991)

  9. ELECTROCOCHLEOGRAPHY:85 Years Old and Still Clinically Important! Ruben (CM & AP clinically) Coats, Eggermont, Gibson (Dx of MD) Tasaki (AP in human) Yoshie, Portmann (TT CM & AP) Davis (SP) Coats (EAC) Fromm et al (CM in human) Various (ANSD, CI) Hall (I/O) Wever & Bray (CM in cat) 1930 1935 1950 1954 1960 1967 1974 1990 1996 Time in Years

  10. Electrocochleography (ECochG):Generators • Cochlear microphonic (CM) • Outer hair cells • Receptor potentials • Summating potential (SP) • Inner hair cells (> 50%) • Outer hair cells • Organ of Corti • Action potential (AP) • Afferent fibers in distal 8th cranial nerve • Spiral ganglion

  11. AP CM SP

  12. Electrocochleography (ECochG):Stimulus Polarity is Important

  13. ECochG Electrode Options: The Closer to the Cochlea, the Better TipTrode Trans-Tympanic Promontory Electrode TM Electrode

  14. TIPtrode: Part Transducer and Part Electrode

  15. Sub-Dermal Needle Electrode for Trans-Tympanic Promontory ECochG Recording

  16. ELECTROCOCHLEOGRAPHY (ECochG):“Traditional” Clinical Applications • Estimation of auditory sensitivity in young and difficult-to-test children • Enhancement of wave I in ABR measurement • Enhance inter-wave latency analysis in neuro-diagnosis • Confirm ear-specific test findings for AC and BC ABR (wave I is a biological marker for ipsilateral 8th nerve) • Minimize the need for masking of non-test ear • Intra-operative neurophysiological monitoring • Prompt documentation of cochlear status • Enhance inter-wave latency analysis • Diagnosis of Meniere’s disease

  17. “Traditional” Clinical Applications of ECochG: Enhanced Wave I and I/O Monitoring

  18. ECochG in Diagnosis of Meniere’s Disease: Abnormally Large SP/AP Ratio Coats AC (1981). The summating potential in Meniere’s and non-Meniere’s ears. Archives of Otolaryngology, 107, 199-208

  19. ELECTROCOCHLEOGRAPHY: Selected Papers(PubMed Search on 9/9/14 at www.nlm.nih.gov with key words “Meniere’s Disease” and “electrocochleography” showed > 400 publications) • Pou, Hirsch, Durrant et al. (1996). Efficacy of tympanic ECochG in the diagnosis of endolymphatic hydrops. AJO, 17 • Levine, Margolis, Daly. (1998). Use of ECochG in the diagnosis of Meniere’s Disease. Laryngoscope,108 • Orchik, Shea, Ge. (1998). Summating potential and action potential ratio in Meniere’s Disease before and after treatment. AJO, 19 • Zack-Williams et al (2012). A comparison of ECochG and high-pass noise masking of ABR for diagnosis of Meniere’s disease. Int J Audiol, 51, 783-787 • Claes et al (2013). Does “cochlear Meniere’s disease exist? An ECochG and audiometric study. Audiol Neurotol, 18, 63-70 • Oh et al (2014). Can we use ECochG as a clinical tool in the diagnosis of Meniere’s disease during the early symptomatic period? Acta Otolaryngol, 134, 771-775

  20. ELECTROCOCHLEOGRAPHY (ECochG):More Recent Clinical Applications • Auditory dysfunction in tinnitus • Cochlear and round window (Soundbridge) implants • Round window and intra-cochlear recordings • Intra-operative verification of cochlear implant function • Intra-operative documentation of low frequency cochlear function during electrode insertion • Prediction of speech perception outcomes • Diagnosis of auditory neuropathy spectrum disorder (ANSD) • Differentiation of pre- versus post-synaptic auditory dysfunction

  21. ELECTROCOCHLEOGRAPHY (ECochG):Cochlear Implant Applications • Harris et al (2011). Preliminary results and technique for electrophysiological intra-operative monitoring of residual hearing during cochlear implantation. Cochlear Implants Int, 12, 209-215 • Mandala et al (2012). Electrocochleography during cochlear implantation for hearing preservation. Otolaryngol Head Neck Surg, 146, 774-781 • Calloway et al (2014). Intracochlear electrocochleography during cochlear implantation. Otol Neurotol, 35, 1451-7 • McClellan et al (2014). Round window electrocochleography and speech perception outcomes in adult cochlear implant subjects: Comparison with audiometric and biographical information. Otol Neurotol, Epub

  22. Role of ECochG in the Diagnosis and Management of Auditory Neuropathy Spectrum Disorder (ANSD) Cerebello-pontine angle (CPA) Internal Auditory Canal (Auditory Nerve) Spiral ganglion cells IHC - 8th CN Synapse (glutamate) Inner hair cells Outer hair cells

  23. Electrococheography (ECochG): Diagnosis of Auditory Neuropathy Spectrum Disorder • Guidelines for the Identification and Management of Infants and Young Children with Auditory Neuropathy (2010). • Panel of Experts: • Yvonne Sininger, Ph.D. • Arnold Starr, M.D. • Christine Petit, M.D., Ph.D. • Gary Rance, Ph.D. • Barbara Cone, Ph.D. • Kai Uus, M.D., Ph.D. • Patricia Roush, Au.D. • Jon Shallop, Ph.D. • Charles Berlin, Ph.D.

  24. Identification and Diagnosis of Auditory Neuropathy Spectrum Disorder (ANSD):Minimal Test Battery (2010 ANSD Guidelines) • Tests of cochlear hair cell function • Otoacoustic emissions (OAEs) • Cochlear microphonic (ECochG and ABR) • CM may be present when OAEs are absent (e.g., with middle ear dysfunction) • Tests of auditory nerve function • ABR for high intensity click stimulation (e.g., 80 to 90 dB nHL) with separate averages for: • Rarefaction stimulus polarity • Condensation stimulus polarity • Additional tests • Acoustic reflex measurement (generally acoustic reflexes are absent in ANSD) • Suppression of otoacoustic emissions (abnormal, e.g, no suppression in ANSD)

  25. Essential Role of Electrocochleography (ECochG) in the Diagnosis and Management of Auditory Neuropathy Spectrum Disorder (ANSD): Medical diagnoses (1) • Perinatal Diseases • Hyperbilirubinemia • Hypoxic insults • Ischemic insults • Prematurity  • Neurological Disorders • Demyelinating diseases • Hydrocephalus • Immune disorders, e.g., Guillain-Barre sydrome • Inflammatory neuropathies • Severe developmental delay

  26. Essential Role of Electrocochleography (ECochG) in the Diagnosis and Management of Auditory Neuropathy Spectrum Disorder (ANSD): Medical diagnoses (2) • Neuro-metabolic diseases • Genetic and Hereditary Etiologies • Family history • Connexin mutations, e.g., GJB3 (D66del) • Otoferlin (OTOF) gene • Non-syndromic recessive auditory neuropathy • Hereditary motor sensory neuropathies (HMSN), e.g., Charcot-Marie-Tooth syndrome • Leber’s hereditary optic neuropathy • Waardenburg’s syndrome • Neurogenerative diseases, e.g., Friedreich’s ataxia • Mitochondrial disorders, e.g., mitochondrial enzymatic defect

  27. Other Procedures Important in the Diagnosis and Management of Auditory Neuropathy Spectrum Disorder (2008 Guidelines) • Components of assessment • Pediatric and developmental history • Otologic evaluation, plus • Imaging of cochlea with CT • Imaging auditory nerve with MRI • Medical genetics evaluation • Ophthalmologic evaluation • Neurological evaluation to assess: • Peripheral nerve function • Cranial nerve function • Communication assessment

  28. Comprehensive Assessment of Auditory Neuropathy Spectrum Disorder (ANSD):MRI of Auditory Nerve • Brainstem and inner ear abnormalities in children with auditory neuropathy spectrum disorder and cochlear nerve deficiency. Huang et al. (UNC). American J Radiol, 31, 2010 • CND was identified in 33.0% of children and 26.9% of ears with ANSD • Significantly more patients with bilateral CND had intracranial abnormalities than those with unilateral CND (60.0% versus 15.8%). • Unilateral auditory neuropathy caused by cochlear nerve deficiency. Liu et al (China). Int J Otolaryngol, 2012. • Cochlear nerve deficiency can be seen by electrophysiological evidence and may be a significant cause of unilateral AN. • Inclined sagittal MRI of the internal auditory canal is recommended for the diagnosis of this disorder.

  29. Auditory Neuropathy Spectrum Disorder ANSD): Defining Site of Dysfunction is the Key to Accurate Diagnosis and Effective Management Action potential (AP) Summating potential (SP) Cochlear microphonic (CM)

  30. ECochG in ANSD: Refining Diagnosis of Site of Dysfunction • Santarelli, Starr, Michalewski & Arlsan (2008). Neural and receptor cochlear potentials obtained by transtympanic electrocochleography in auditory neuropathy. Clinical Neurophysiology, 119, 1028-1041. • 8 subjects (with AN versus 16 normal subjects (5-48 years) • Diagnosis: Presence of DPOAEs and absence of ABR • Enlarged CM in AN patients • Etiology • Hereditary (3) Immunolological (3) • Degenerative (1) Congenital (1) • ECochG measures included • CM • SP • AP

  31. ECochG in ANSD: Refining Diagnosis of Site of Dysfunction (1) • McMahon, Patuzzi, Gibson & Sanli. (2008) Frequency-specific electrocochleography indicates that presynaptic and postsynaptic mechanisms of auditory neuropathy exist. Ear & Hearing, 29, 314-325. • Subjects • 14 subjects (7 male and 7 female) with AN versus 2 normal subjects( Dx at 3-24 months) • Diagnosis: large CM potentials and absent ABR • Genetic etiology for 6 subjects • Severe to profound audiometric thresholds • All subjects received cochlear implants • ECochG recorded with non-inverting “golf club” electrode near round window electrode via myringotomy

  32. ECochG in ANSD: Examples of ECochG Components(McMahon et al, 2008) CM Condensation Rarefaction Alternating N2 SP N1 DP (dentritic potential) Analysis Time 10 ms

  33. ECochG in ANSD: Refining Diagnosis of Site of Dysfunction (2) • McMahon, Patuzzi, Gibson & Sanli. (2008) Frequency-specific electrocochleography indicates that presynaptic and postsynaptic mechanisms of auditory neuropathy exist. Ear & Hearing, 29, 314-325. • Purpose of study was to better define physiology mechanisms of AN to guide management including cochlear implantation • ECochG in AN consistent with: • Pre-synaptic mechanism (abnormal SP) = good EABR and CI benefit • Post-synaptic mechanism (normal SP + dentritic potential) but no AP = poor or absent EABR and poor CI benefit

  34. Update on Auditory Electrophysiology • Introduction to auditory electrophysiology … 85-years of research and clinical application • Electrocochleography (ECochG) … It’s for much more than just the diagnosis of Meniere’s Disease • ABR … Over 11,000 peer-reviewed publications with > 4000 within the past decade alone! • ASSR … Filling an important niche in children and adults • Cortical auditory evoked responses … Now we’re really assessing hearing • Summary, Questions & Answers

  35. The First Comprehensive Description of the Auditory Brainstem Response (ABR) in Humans Jewett D and Williston J. Auditory evoked far fields averaged from the scalp of humans. Brain 4: 681-696, 1971. Don Jewett

  36. Jewett & Williston, 1971Normal Subject Waveform Consistency … the Ideal Clinical Tool

  37. Auditory Brainstem Response (ABR):An Evidence-Based Test Protocol 0.5 uV V I III Stimulus Clicks Tone bursts Speech 8 ms Electrodes Auditory Evoked Response System Filters Amplifiers Signal Averager

  38. Generators of ABR Waves: A Far-Field Response from Sub-Cortical Auditory Pathways • Generator sites • I = Distal auditory nerve • III = Caudal brainstem • V = Lateral lemniscus • Relation between anatomy and response • Multiple structures contribute to single waves • Waves reflect axonal activity • Laterality • Wave I = ipsilateral to stimulus • Waves III and V = contralateral to stimulus

  39. Robert Galambos, MD, PhDDirector of the Laboratory (Yale University) Where the ABR was “Discovered” and Pioneer of Early Pediatric Applications of ABR • 1974: Hecox KE & Galambos R. Brain stem auditory evoked responses in human infants and adults. Archives of Otolaryngology 99. • 1975: Schulman-Galambos C. & Galambos R. Brain stem evoked responses in premature infants. JSHR 18. • 1979: Schulman-Galambos C. & Galambos R. Brain stem evoked response audiometry in newborn hearing screening. Archives of Otolaryngology 105:

  40. James Jerger, Ph.D. “Father of Diagnostic Audiology” Baylor College of Medicine and Methodist Hospital, Houston TX Larry Mauldin Circa 1975 Helped Build Early AER System

  41. The Cross-Check Principle in Pediatric Audiology(Jerger J & Hayes D. Arch Otolaryngol 102: 1976)

  42. The Cross-Check Principle Pediatric Audiology(Jerger J & Hayes D. Arch Otolaryngol 102: 1976) “We have found than simply observing the auditory behavior of children does not always yield an accurate description of hearing loss”… “The basic operation of this principle is that no result be accepted until it is confirmed by an independent measure.” Test Battery: • Behavioral audiometry • Immittance (impedance) measurements • Tympanometry • Acoustic reflexes (contralateral only with SPAR) • Brainstem-evoked response audiometry (BSER now ABR) • Click stimulus air conduction • Click stimulus bone conduction

  43. 1948 Vintage Audiologist Using 1980 Model Nicolet CA-1000 with Infamous “Aural Dome” TDH Earphones

  44. 40 Years of Evidence-Based ABR Applications (> 11K Pubs) Since Hecox & Galambos (1974) • Newborn hearing screening • Diagnosis of hearing loss in infants and young children • Frequency-specific estimation of auditory sensitivity • Differentiation of conductive vs. sensorineural hearing loss • Neuro-diagnosis of retrocochlear and brainstem disorders in children and adults • Neurophysiological monitoring • Intra-operative during surgical procedures • Neuro-intensive care unit in head injured patients • Description of neural representation of auditory processing in brainstem with speech evoked ABR

  45. Auditory Brainstem Response: The Research Continues Unabated (> 350 Publications Each Year) • Descriptions of ABR applications in new clinical entities and populations • Replications of traditional ABR studies in countries with emerging or rapidly growing audiology communities, e.g., India, China, Brazil, Brazil, Iran • Studies of auditory processing with speech evoked ABR • Investigations of new technology for ABR measurement

  46. Auditory Brainstem Response:Applications in New Clinical Entities and Populations (Plus new technology and studies in emerging audiology countries) • Elkabariti et al (2014). Speech evoked auditory brainstem response findings in children with epilepsy. Int J Pedi ORL, 78, 1277-80 (Egypt) • Talebi & Rezazadeh (2012). The role of ABR in diagnosing auditory impairments of Dejerine-Sottas. Int J Pedi ORL, 76, 915-917 (Iran) • Jecmenica & Opancina (2014). Characteristics of brain stem auditory evoked potentials in children with hearing impairment due to infectious diseases. J Child Neurol, Epub (Serbia)

  47. Auditory Brainstem Response:Applications in New Clinical Entities and Populations • Allen & Allan (2014). Auditory processing disorders: Relationship to cognitive processes and underlying neural integrity. Int J Pedi ORL, 78, 198-208 (click ABR and ARs) • Hasani & Jafari (2013). Effect of infant prematurity on ABR at preschool age. Iran J ORL, 25, 107-114 (Iran) • Kouni et al (2013). Brainstem auditory evoked potentials for acoustic clicks and complex verbal sounds in young adults with learning disabilities. Am J Otolaryngol, 34, 646-651 (Greece) • Quevedo et al (2012). Auditory brainstem response in gas station attendants. Brazilian J ORL, 78, 63-68 • Weich et al (2012). Brain stem evoked response audiometry in former drug users. Brazilian J ORL, 78, 90-96

  48. Auditory Brainstem Response:Revisiting Old Research Topics • Stevens et al (2013). ABR in newborns: Effects of electrode configuration, stimulus rate, and EEG rejection levels on test efficiency. Int J Audiol, 52, 706-712 • Liu & Liu (2013). Hearing screening and diagnosis in a large sample of infants in central China. J Med Screen, 20, 21-26 (N = 11,894) • Vinodh et al (2014) Reversibility of brainstem evoked response audiometry abnormalities at 3 months in term newborns with hyperbilirubinemia. Indian Pediatr, 51, 134-135 (India) • Jiang & Wilkinson (2014). Impaired function of the ABR in term neonates with hyperbilirubinemia. Brain Dev, 36, 212-218 (China)

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