program. 5/15/2015 your name here 2 acoustics seminar catarina hiipakka 28.01.2015 diagnosing...
TRANSCRIPT
Program
04/18/23
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Acoustics SeminarCatarina Hiipakka28.01.2015
Diagnosing Hearing Loss
Part 1: Hearing Disorders
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Some concepts
• Congenital
• Hereditary or genetic
• Acquired
• Pre- or Postlingual
Sensorineural
• Cochlea
• Auditory nerve
• Often hair cells, auditory neurons
• Threshold – where in cohlea
• Outer hair cells – common and mild to moderate
• Inner + Outer - severe
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Dead regions
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Don’t regenerate!No processingIC, neurons>50 dB
Not a dead region. OHC loss
Outer Hair Cells
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Also: Loudness recruitment
Sensorineural Hearing Loss
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• High frequencies
• Diplacusis – more than one pitch
• Loudness recruitment
• Presbycusis – age
• “I hear, but I cannot understand”
• Time resolution
Place theoryFrequency theory
Volley Principle
Conductive Hearing Loss
No distortion
No frequency specificity
Low level
Comfort in loud sounds, places – paracusis willisii
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Tinnitus and Hyperacusis
• Who has it?
• Subjective Tinnitus
• Objective Tinnitus: Circulation, temporomandibular joint, muscles
• 6 to 30% chronic tinnitus
• 1 to 2.5% clinically affected life
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Tinnitus and Hyperacusis
• 45% of tinnitus have hyperacusis
• 86% of hyperacusis have tinnitus
• Intolerance
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Other disorders
• Autosomal dominant inheritance• Autosomal recessive inheritance• Maternal infections, environment
• Head trauma• Impacted cerumen• Foreign bodies• Otitis• Otosclerosis• Retrocochlear disorders (brainstem)• Central auditory processing disorders
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Part 1: Wrap Up
Sensorineural Hearing Loss
Cochlear Dead Regions
Outer Hair Cells
Conductive Hearing Loss
Tinnitus
Others
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Part 2: Audiometry
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Normal HearingMinimum Audible Field
Minimum Audible Pressure
The Audiometer
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The Audiometer
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Bone Conduction
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More than an Audiometer!
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Hearing Level
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dB SPL to HL
Hearing Level
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Hearing loss at high frequencies
Normal (HL)
example
Audiometer Calibration
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ANIS/ISO Hearing Level – several standards
Audiometer Calibration
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Audiometer Calibration -Bone Conduction
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Artificial mastoid/mechanical coupler Test close-up
And Biological Calibration
Pure-Tone Audiometry
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1kHz 2kHz 4kHz 8kHz 1k 500Hz 250Hz
Pure-Tone Audiometry
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Results: Sensorineural and Conductive Hearing Loss
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Results
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Results: Considerations
Standing waves at 8kHz
Tactile responses
Acoustical radiations (bone conduction)
Collapsed ear canals
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Summing up: AUDIOMETRY
- Thresholds
- Level of hearing loss
- Sensorineural vs. Conductive
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Part 3: Other Diagnostic Procedures
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Acoustic Immittance
Immittance: Impedance, Admittance
Acoustic Immittance
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85dB 226 Hz probe tone
Acoustic ImmittanceTympanometry
varying pressure
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Otosclerosis
Scarred eardrums
Ossicular discontinuities
Middle ear fluid,Eardrum perforation
Eustachian tubedisorders
Acoustic Reflex
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Acoustic Reflex
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Speech Audiometry
• Speech audiometer
• Thresholds for speech• Speech detection• Speech reception (SRT)
• Signal-to-noise ratio
Words, syllables, sentences/several words
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Wrapping up
• Screening: Pure-tone air conduction
• Diagnosing: also • bone conduction, • tuning forks,• questionnaire, • speech reception, • acoustic immittance (if conductive)
• And more…
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Today’s question
How do you detect if a patient has conductive hearing loss?
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