Audiology 101: Audiology for non-audiologists working with and supporting EHDI activities

1. Audiology 101:Audiology for non-audiologists working with and supporting EHDI activities Terry E. Foust, Au.D., FAAA, CCC-A/SLP Jeff Hoffman, MS, CCC-A National Center for Hearing Assessment and Management

2. What are Audiologists? Specialists in Hearing and Balance • Prevention of hearing loss • Identification and assessment of hearing and balance problems • Rehabilitation of persons with hearing and balance disorders

3. Ear

4. Outer Ear • Pinna • External Auditory Canal (Ear Canal) • Tympanic Membrane (Ear Drum)

5. Middle Ear Ossicles (bones) Eustachian Tube

6. Inner Ear Cochlea Organ of Corti Hair Cells

7. Structures of the Central Auditory System VIIIth Cranial Nerve (Auditory Nerve) Auditory Cortex

8. Types of Hearing Loss Conductive = Outer and/or Middle Ear Sensorineural = Inner Ear Mixed = Outer and/or Middle and Inner Ear Auditory Neuropathy Spectrum Disorder (aka Auditory Neuropathy / Dys-synchrony) = Central Auditory System --------------------------------------------------------------------- Unilateral = one ear Bilateral = two ears

9. Permanent Congenital Hearing Loss: CDC HSFS, 2009 Conductive Hearing Loss – 13.6%

10. Permanent Congenital Hearing Loss: CDC HSFS, 2009 Sensorineural Hearing Loss – 58.6%

11. Permanent Congenital Hearing Loss: CDC HSFS, 2009 Mixed Hearing Loss – 7.3%

12. Permanent Congenital Hearing Loss: CDC HSFS, 2009 Auditory Neuropathy Spectrum Disorder – 3.4%

13. Permanent Congenital Hearing Loss: CDC HSFS, 2009 Unilateral Hearing Loss – 33.1%

14. Permanent Congenital Hearing Loss: CDC HSFS, 2009 Bilateral Hearing Loss – 59.0%

15. Permanent Congenital Hearing Loss: CDC HSFS, 2009 Laterality Unknown – 7.8% ? ?

16. Incidence of Congenital Hearing LossCDC EHDI Survey – 2009 Children = 5103 Unilateral = 33.1 % Bilateral = 59.0 % Laterality Unknown = 7.0 % Ears = 8112 Conductive = 13.6 % Sensorineural = 58.6 % Mixed = 7.3 % Auditory Neuropathy Spectrum Disorder = 3.4 % Unknown = 17.0 %

17. TheAudiogram – A graph of an individual’s hearing sensitivity, including type and degree of hearing loss Audiogram Frequency Low Pitch to High Pitch Loudness Soft to Loud

18. Speech Sounds

19. The Audiogram

20. The Audiogram

21. Take Home Message • Hearing loss is described by the parts of the ear affected and can be temporary, permanent and/or fluctuating • An audiogram is how we graph hearing sensitivity and it is very important to develop an understanding of what it means • Even mild and moderate hearing loss significantly affects ability to hear speech which affects speech and language development

22. JCIH Newborn Hearing Screening Guidelines 1-3-6 Model By 1 month Screen hearing By 3 months: Evaluate hearing and complete diagnostic audiology and otolaryngology examinations Fit hearing aids if necessary By 6 months: Enroll in Early Intervention Services

23. Why the rush??

24. Four Main Tests • Tympanometry • measure of middle ear function (evaluates middle ear pressure) • status of middle ear system • confirm/rule out conductive or temporary hearing loss • Otoacoustic emissions- OAE • measurement of sounds generated by the outer hair cells of the inner ear or cochlea • measured and recorded in ear canal • indicative of inner ear function • Auditory Evoked responses- ABR • recording of brain waves in response to sound • response from brainstem • Behavioral

25. Objective Tests • Do not require a behavioral response • Objective measure of the status of auditory system • Middle ear function (Tympanometry) • Inner Ear Function (OAE) • Function of central pathways in the brainstem and cortex (ABR)

26. Tympanometry Measured at the plane of the ear drum or Tympanic Membrane Record how much acoustic energy is transferred into the middle ear Determine the condition of the middle ear from this measurement - hole or perforation of the eardrum - fluid behind the ear drum - air pressure behind the ear drum - normal ear drum movement

27. What are Otoacoustic Emissions? • sounds measured in the external ear canal that are generated by the outer hair cells in the cochlea

28. OAE Overview • Sound stimulus goes into the ear canal • If the eardrum and middle ear system is healthy AND the Inner Ear is normal • Then a response ( echo ) from the movement of the outer hair cells can be measured • Babies are the easiest to test when they are: • Younger • Quiet or distracted

29. Detection of OAEs Undetectable in hearing losses of 30 dB HL or greater Does not tell us anything about the degree of hearing loss

30. Auditory Evoked Potentials • ABR- auditory brainstem response occurs in the first 10-15 msec after a sound enters the ear • “Waves” generated by synchronous nerve firing- volley • Waves I and II VIII nerve • Wave III Superior Olivary Nucleus level of pons • Wave IV Lateral Lemniscus pons • Wave V Inferior Colliculus level of mid-brain

31. ABR Pathways

32. ABR • Evaluate nerve conduction delays- timing • Estimate hearing threshold • Electro-physiologic response 10-20 dB above behavioral threshold

33. ABR Threshold searchfrom Hearing in Children, Northern and Downs, C7 pp 238to 257

34. ABR ABR Normal Threshold ABR Mild Hearing Loss Threshold

35. Why use ABR? • ABR not affected by patient state or anesthesia- brainstem level response • Natural sleep or sedation to estimate threshold in infants and children • Later waves from higher centers response affected by alertness/state • Sedation or some medications will suppress the middle and late responses

36. Behavioral Tests Visual Reinforcement Audiometry (VRA) Conditioned Play Audiometry (CPA)

37. Treatment and intervention Medical intervention • surgical treatment • treatment for chronic middle ear disorder Hearing aids Cochlear implants FM systems

38. Treatment and Intervention • Early intervention for overall development • Communication modalities • Emotional • Social • Cognitive • Audiologist work with and refer to • Early interventionists • Speech-language therapists – specialized in hearing impairment • Educators for the deaf or hard of hearing

39. JCIH 2007 Amplification Infants diagnosed with permanent hearing loss should be fit with amplification within one month of confirmation of HL

40. Hearing Aids • Hearing aids can be fitted as young as 1 month of age

41. Hearing Aids

42. Cochlear Implant Candidacy Criteria • Lack of benefit from amplification • Age: 12 months (FDA, insurance) but sometimes younger • Degree of hearing loss: bilateral severe to profound • No medical contraindications • Education environments and services appropriate for post-CI aural re/habilitation • Family factors (motivation, expectations)

43. Cochlear Implant

44. FM Systems

45. Monitoring and managing hearing loss • Hearing can change and get worse • Plan for future needs - amplification flexibility • Monitor hearing aid/cochlear implant function – trouble shoot • Provide educational input and consultation - classroom modifications - FM - educational strategies

46. How to work collaboratively with audiologists • Make out reach efforts - individual or group • Encourage mutual information sharing • Invite participation • Keep asking questions

47. Take Home Message • Infants can and should be assessed as soon as possible to maximize development of maturing auditory skills; sets the stage for language development • Family choices for intervention often includes hearing aids/Cochlear Implants AND early intervention (communication strategies) • Questions about hearing? Ask your Audiologist