1. Electrophysiological Measures of the Auditory System
Perry C. Hanavan, Au.D.
Audiologist

2. Electrophysiological Tests
Immittance
Evoked Potential
Otoacoustic Emissions

3. First
Observations
Appearance of person, age, gender, unusual characteristics
Patient information, case history, self-assessment, other clinical data
Otoscopic exam

4. Electrophysiologic Triage Trio
Tympanogram
Acoustic Reflex
Otoacoustic Emissions

5. Triage Trio
Normal peripheral and lower brainstem function (possible APD) normal hearing
Tympanogram
Type A
Acoustic Reflexes
Normal
OAE
Normal
Cochlear loss, outer hair cell loss, ABR normal, hearing aids beneficial
Tympanogram
Type A
Acoustic Reflexes
Normal Range
Normative Data
OAE
Absent or
Depressed
Auditory
Neuropathy/
Dys-synchrony
Tympanogram
Type A
Acoustic Reflexes
Absent or Elevated
OAE
Present
Severe or profound inner ear loss (occasionally otosclerosis)
Tympanogram
Type A
Acoustic Reflexes
Absent
OAE
Absent
Conductive or mixed loss (possible severe/profound loss)
Tympanogram
Not Type A
Acoustic Reflexes
Absent
OAE
Absent

6. Immittance Testing Ear Canal Volume (ECV or PVT) Tympanometry
Static Compliance
Acoustic Reflex, Decay, & Latency

7. Ear Canal Volume Measure at +200 mmH20
Provides measure of volume of external ear canal
Volumes based on age
Volumes greater than 2.5 mmH2O (adult) or 2.0 (child) suggest:
Perforation or
Patent PE tube

8. Tympanometry
Objective measure of the function of the TM and middle ear
5 or 6 basic shapes

9. Question Which type tympanogram indicates normal middle ear function?
B lo C Ad As Ap

10. Tympanogram Types

11. Type A Tympanogram OE ME IE AN
CNS AC A BC
Normal or SN

12. Type AD Tympanogram OE ME IE AN
CNS AC A D BC
Disarticulation

13. Type AS Tympanogram OE ME IE AN
CNS AC A S BC
Otosclerosis

14. Type BLow Tympanogram OE ME IE AN
CNS AC B
Low BC
OME

15. Type BHi Tympanogram OE ME IE AN
CNS AC B Hi BC
Perforation

16. Eustachian Tube Dysfunction
Type C Tympanogram OE ME IE AN
CNS AC C BC
Eustachian Tube Dysfunction

17. Type AP Tympanogram OE ME IE AN
CNS AC A P BC
Acute Otitis Media

18. Static Compliance (Peak Compliance)
Static Compliance – SC
Ear Canal Volume – ECV
Middle Ear Volume – MEV
Peak Volume – PV
SC = PV – ECV
The ECV reflects the volume in the ear canal as the ECV measure is often made at +200 in which the TM is very stiff reflecting most of the acoustic energy (acoustic energy is not absorbed by middle ear)
The PV reflects the ear canal volume AND the middle ear volume as the measure is made where the tympanogram peaks or in other words, the measure is made where the TM is most compliant or mobile; thus it is assumed that the PV represents the volume of the OE and the ME.
Thus, the SC, or PV minus the ECV, represents the ME volume
The normal range for our equipment ranges from .25 to 2.5 OE
Ear Canal Volume
(ECV) ME
Volume
(Static Compliance)
OE and ME
Volume
(Peak Volume)

19. Static Immitance
The terms peak compliance (ml, cc or cm3) and peak static acoustic admittance (mmho) can be used interchangeably when using a 226Hz probe tone.
Most references use the term static admittance (SA) when reporting results.
In the most recent edition of Katz et al 2009, there is a comprehensive list of large scale studies that reported normative ranges for peak SA.
Summarizing across these studies, the 90% range for a normal tympanogram is .2 to 1.8.  Shanks, J., & Shohet, J (2009). Tympanometry in clinical practice. In J. Katz, L. Medwetsky, R. Burkard, & L. Hood (Eds.), Handbook of clinical audiology (6th ed.) (pp ). Baltimore: Lippincott, Williams & Wilkins.

20. Static Compliance (Peak Compliance)
Acceptable Range by Age
Flaccid: disarticulation, flaccid TM, etc.
0.9
1.8
Normal mobility
0.2
0.3
Stiff: otosclerosis, fluid, tympanosclerosis, etc.
Child
Adult

21. Tympanometric Width Normative Cutoff Values (if larger, abnormal)
Infant: daPa
1 – 10 yr olds: daPa
Adults: daPa

22. ART

23. Abnormal ART

24. Recruitment ART – AC PT =< 60 indicates recruitment
(cochlear pathology)

25. Reflex Decay

26. Bekesy vs. Gold Bekesy Gold Passive Broadly tuned Studied dead cochlea
Awarded Nobel Prize
Gold
Active
Fine tuned
Studied live responses
Went on as an astronomer

27. Otoacoustic Emissions
David Kemp disovered OAEs
Acoustic energy produced by the cochlea and recorded in the external auditory canal
Most likely energy produced by outer hair motility and possibly outer hair cell cilia
Objective test
DPOAE
TEOAE

28. DPOAE

29. DPOAE

30. Tympanogram type. Acoustic thresholds. OAE results
Tympanogram type? Acoustic thresholds? OAE results? Expected type of hearing loss? ECV? Normal? Static Compliance? Normal?

31. Tympanogram type?
Acoustic thresholds?
OAE results?
Expected type of hearing loss?
ECV? Normal?
Static Compliance? Normal?

32. Tympanogram type?
Acoustic thresholds?
OAE results?
Expected type of hearing loss?
ECV? Normal?
Static Compliance? Normal?

33. Tympanogram type?
Acoustic thresholds?
OAE results?
Expected type of hearing loss?
ECV? Normal?
Static Compliance? Normal?

34. Tympanogram type?
Acoustic thresholds?
OAE results?
Expected type of hearing loss?
ECV? Normal?
Static Compliance? Normal?

35. Tympanogram type?
Acoustic thresholds?
OAE results?
Expected type of hearing loss?
ECV? Normal?
Static Compliance? Normal?

36. Why was the AB-Gap in the left ear not expected?

37. Evoked Potentials
EcochG
ABR
Middle Latency
Late Response

38. OAE & ABR Screen

39. ABR Wave I Auditory Nerve II Auditory Nerve III Cochlear Nuclei IV SOC
Interwave Latencies
Absolute Latencies

40. ABR Waves & Physiology

41. ABR Supra-aural Phone Data
Add .9 to Absolute values when using insert phones

43. Newborn ABR Latency Data

44. Auditory Processing Dichotic Sentence Identification
Dichotic sentence testing is a binaural separation test procedure used to determine levels of auditory maturation, hemispheric dominance for language, and to identify disordered or damaged central auditory pathways.
The advantage of testing binaural separation with both word and sentence stimuli is to compare findings obtained with both simple and more complex linguistic levels of auditory stimuli.

45. Dichotic Sentence Identification
The DSI test uses 6 of the same sentences as the SSI-ICM test but presents 1 sentence to each ear simultaneously at 50-dB SL, and the participant is asked to select from a printed list which 2 sentences were heard.
Fifer et al showed that the test is resistant to the effects of SNHL below 50 dB HL.
The DSI test is administered in both a free and a directed mode.
In the directed mode, only the sentence heard in test ear is noted, whereas in the free mode, the sentences heard in both ears are reported.
Five presentations are used if the score is 100%; otherwise, another 5 sentences per ear are administered.
Scores are better in the directed mode than in the free mode, and the right ear scores are normally higher in adults than the left ear scores, presumably due to age related corpus callosum dysfunction.
Normal scores are 80% correct and above.

46. Pediatric Speech Intelligibility (Closed Set)(Recorded)
PSI
Both monosyllabic words and sentences recorded in quiet and with competition.
Employs color plates with pictures of animals (animals used to avoid ethnic biases) which represent either the sentences or the words.
Investigates peripheral and auditory processing disorders.

47. BKB-SIN (Adults)

48. BKB-SIN (Children)

49. Fig 8-1
ECV= .5
ECV= .6

50. Fig 8-2 Normal Functional Outer Ear Middle Ear Inner Ear
Auditory Nerve
CNS
ECV= .9
ECV= 1.3

51. Fig 8-3 Normal Functional Outer Ear Middle Ear Inner Ear
Auditory Nerve
CNS

52. Fig 8-4 Normal Functional Outer Ear Middle Ear Inner Ear
Auditory Nerve
CNS

53. Fig 8-5 Normal Functional Outer Ear Middle Ear Inner Ear
Auditory Nerve
CNS

54. Fig 8-6 Normal Functional Outer Ear Middle Ear Inner Ear
Auditory Nerve
CNS

55. Fig 8-7 Normal Functional Outer Ear Middle Ear Inner Ear
Auditory Nerve
CNS

56. Fig 8-8 Normal Functional Outer Ear Middle Ear Inner Ear
Auditory Nerve
CNS

57. Fig 8-12

58. Fig 8-14 Normal Functional Outer Ear Middle Ear Inner Ear
Auditory Nerve
CNS

59. Fig 8-15