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Marine Mammal Bioacoustics: Audiology Vocal Pathology

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    1. Marine Mammal Bioacoustics: Audiology / Vocal Pathology Peter M. Scheifele MDr, PhD, LCDR USN (Ret.) University of Cincinnati Communication Sciences and Disorders, Neuroaudiology Dept. University Medical Center scheifpr@uc.edu

    2. 2

    3. Graphical Hearing Descriptors AUDIOGRAM- a graph expressing hearing loss (sensitivity) as a function of frequency. HEARING THRESHOLD CURVE- a graph expressing the level of intensity at which a sound is just audible to an individualAUDIOGRAM- a graph expressing hearing loss (sensitivity) as a function of frequency. HEARING THRESHOLD CURVE- a graph expressing the level of intensity at which a sound is just audible to an individual

    4. The Hearing Threshold Curve

    5. Beluga Whale Hearing Threshold Curve

    7. 7 Audiometric Zero (Ref ANSI S3.6 1996, TDH-39 earphones) 0 dB Hearing Level at 1000 Hz = 7 dB SPL

    8. 8 Graphic Audiograms Provides a pictorial representation of hearing thresholds as a function of frequency and intensity Uses symbols and/or colors to represent right ear, left ear, bone conduction hearing and masking levels

    9. 9 Graphic Audiograms

    10. Sound Pressure Level (SPL) The physical power in a sound as determined from a sound pressure measurement dB SPL = 20 log Px/Pref Pref = 20 Pa

    11. Sound Pressure Level (SPL) The amount of power needed for a normal hearing human to perceive a sound at threshold varies across frequency The amount of power needed also depends upon the transducer ANSI 1996 standards

    13. Hearing Level (HL) Hearing Level (dB HL) refers to the level in dB relative to the audiometric norm Normalizes minimal audible pressure levels across frequency 0 dB HL = average threshold for a specific frequency Range of normal hearing is from -10 dB HL to 20 dB HL Used on audiometer dials and the audiogram to plot hearing levels

    16. Converting dB SPL to dB HL If the minimal audible pressure perceived by a human at 500 Hz is 11.5 dB SPL, what is it in dB HL? If audiometric zero is 45 dB SPL at 125 Hz, what level in dB HL is the same frequency sound when it is presented at 85 dB SPL?

    17. Converting dB SPL to dB HL If audiometric zero is 11 dB SPL at 2000 Hz, what level in dB HL is the same frequency sound when it is presented at 61 dB SPL? If the minimal audible pressure perceived by a human at 4000 Hz is 17 dB SPL, what is it in dB HL?

    18. Sensation Level (SL) Sensation Level (dB SL) is the level in dB relative to an individuals own hearing thresholds Regardless of hearing ability, a persons own threshold is set to 0 dB and the level of any particular sound is specified in terms of that threshold

    19. Sensation Level (SL) A sound that is 30 dB more intense than the sound level at a persons threshold is described as 30 dB SL A sound that is 75 dB more intense than the sound level at a persons threshold is described as 75 dB SL

    20. Sensation Level (SL) Sensation Level can be defined in terms of a persons threshold for: one frequency pure tone average (PTA) speech recognition threshold (SRT) Clinical speech testing- stimulus level is presented in dB SL re: PTA, or SRT 50 dB SL, 70 dB SL

    21. Converting dB HL to dB SL If a persons threshold at 1000 Hz is 10 dB HL, what is the sensation level of a 1000 Hz tone presented at 60 dB HL? If a persons threshold at 2000 Hz is -5 dB HL, what is the intensity in dB HL of a 2000 Hz tone presented at 35 dB SL?

    22. Converting dB HL to dB SL If persons pure tone average is 5 dB HL and speech testing material is presented at 50 dB SL, at what dB HL is the word list presented? If a persons speech recognition threshold is measured to be 20 dB HL and speech testing material is presented at 70 dB HL, what is the sensation level?

    23. 23 Degrees of Hearing Loss Normal Hearing -10 - 25 dB HL Mild Hearing Loss 30 - 45 dB HL Moderate Hearing Loss 50 - 65 dB HL Severe Hearing Loss 70 - 85 dB HL Profound Hearing Loss > 90 dB HL

    24. 24 Hearing Loss Zones

    25. 25

    26. 26 Cross-over One ear hears much better than the other The sound presented to the test ear crosses through the skull and stimulates the hair cells of the cochlea of the non-test ear The non-test ear is the one actually responding to the tone Differences of > 40 dB at the same frequency between ears are suspicious

    27. 27 Cross-over

    28. 28 Making Diagnoses

    29. Thresholds and Threshold Shifts Threshold = JND at 50% detection rate Pure-tone Differential Detection/hearing/of audibility Acoustic reflex Masked/unmasked (speech) recognition Pain Threshold shift TTS PTS Time-weighted average (TWA)

    30. 30 Malingering (Pseudohypacusis) (Exaggerated Hearing Loss) Pretending to have a hearing loss by waiting until the sound is quite loud before pressing the response button

    31. Hearing Losses May be due to: Cochlear disorders Auditory nerve disorders Central auditory pathology Conductive disorders (bone) Noise-induced Inherited disorders Presbycusis (age-related) May be congenital or Late-onset

    32. Sensorineural versus Conductive Conductive Loss- Due to outer or middle ear blockage or loss of bone conduction via the skull. Sensorineural Loss- Loss of inner ear functions of either hair cells or auditory nerve damage Central Auditory Processing Disorders (CAPD)- Due to lesions or other brain pathologies

    33. 33 Sensorineural Hearing Loss

    34. 34 Conductive Hearing Loss

    35. Vocal Pathologies: Functional Correlates Overview Sound production issues Dysphonia Aphonia Mechanical Neurological

    36. Fini