Marine Mammal Bioacoustics: Electrophysiological Studies of Hearing

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Marine Mammal Bioacoustics Electrophysiological
Studies of Hearing Cognition

• Peter M. Scheifele MDr, PhD, LCDR USN (Ret.)
• University of Cincinnati
• Communication Sciences and Disorders,
  Neuroaudiology Dept.
• University Medical Center
• scheifpr_at_uc.edu

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What Electrophysiological Studies??

• AEP versus ERP
• AEP
• Ecogh
• ABR
• MLR
• ERP
• P300
• N400

Image from http//www.audiospeech.ubc.ca/haplab/
aep.htm
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Electrocochleography
Recording of compound cochlear nerve action
potential at the Round Window
Image from http//www.iurc.montp.inserm.fr/cric51
/audition/
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Electrophsyiology ofMarine Mammals
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Cetacean ERP
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EQUIPMENT POSITIONING FOR ABR TESTING
A
G
R
MH
H
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Marine Mammal Hearing / ERP Testing
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ERP of Bottlenose Dolphin(Tursiops truncatus)
FROM Woods et al., 1986
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Five general response categories in ABR testing

• Fast responses
• SWR responses (slow wave) components
• Middle responses
• Slow responses
• Late responses

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Mid, Slow and Late ERPs
                                     
FROM Scott and Bhattacharyya, 2001
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Auditory Evoked Potentials
Why dear, its a wood tick not a brain!
Surface electrodes placed on the skull allow
recording of 5 main waves of electrical activity
through the brainstem.
Image from http//www.iurc.montp.inserm.fr/cric51
/audition/
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ABR Accuracy and Limitations

• Some limitations on accuracy.
• ABR waveform in response to high-intensity
  clicks.
• If the cochlea is damaged the ABR will fail.

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Auditory Brainstem Response (ABR)

• Doubling of nerve fiber diameter doubles
  conduction velocity.

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ABR from False Killer Whale(Pseudorca
crassidens)FROM Dolphin, W.F., 1993
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Comparison of Behavioural versus
Electrophysiological Audiograms for a False
Killer Whale (Pseudorca crassidens) FROM
Dolphin, W.F., 1993
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Equipment Set-up for AEP Testing on Dolphins
FROM Dolphin, W.F., 1993
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ABR Intensity Series of a Bottlenose Dolphin
(Tursiops truncatus) FROM Dolphin, W.F., 1993
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LATE POTENTIAL TESTING LOOKING FOR LANGUAGE
COGNITION