Hearing Measurement 1

Course Goals

• The course provides SLP students a foundation for understanding audiometric results.
• The course provides AUD students a basis for more advanced training.
• The course covers basic principles and techniques in audiology.
• What the basic audiological tests are is covered.
• How to perform the basic audiological tests is covered
• What information each test provides is covered.
• How this information is used is covered.

Types of Diagnosis

• Physiological diagnosis determines what is might be wrong.
• Physiological diagnosis can determine if surgery is a better treatment option than a hearing aid.
• Rehabilitative diagnosis focuses on how to help people overcome obstacles.

Perspective

• Audiologists work similarly to otologists when inspecting a TM or assessing the middle ear.
• Audiologists work similarly to neurologists when performing electrophysiologic tests or checking neural reflexes.
• Audiologists work similarly to engineers when adjusting the parameters of a hearing aid.
• The focus for audiology is the assessment and rehabilitation of receptive communication.

International Classification of Functioning Disability and Health

• Disability is "Biopsychosocial"
• Body level is assessed via Function/impairment.
• Person level is assessed via Activity limitations.

Physiologic Diagnosis

• Concerns the body level, specifically the structure and function.
• Addresses issues such as:
  • If hearing is normal or abnormal
  • The site of lesion
  • The cause of hearing issues
  • The prognosis

Rehabilitative Diagnosis

• Concerns the person level, specifically activities and participation.
• Addresses issues such as:
  • Is hearing problematic or unproblematic
  • Hearing capacity
  • If problems understanding speech are present
  • Mitigating effects of hearing loss
  • Helping a person to overcome limitations

Physiologic Perspective

• Different types of hearing loss require different types of treatment.

Rehabilitative Perspective

• Hearing loss is often normal, such as presbyacusis.
• Hearing loss isn't typically a medical concern.
• Hearing impairments almost always interfere with communication, called "Activity Limitation".
• Hearing impairments generally have a negative impact on life in general, called "Participation Restriction".

Audiological Diagnosis

• Audiological diagnosis examines the body, and the person.

Course Topics

• Pure-tone Air and Bone-Conduction Measures
• Audiometric Masking
• Speech Testing
• Pseudohypoacusis
• Hyperacusis and Tinnitus
• Hearing Loss Prevention
• The Immittance Battery
• Otoacoustic Emissions
• Paediatric Assessment
• Electrophysiologic Measures
• Hearing Aids and Implants

Course Format

• Lectures and integrated lab demonstrations
• Readings with workbook
• Case quizzes
• Hands-on laboratory experiences
• Midterm examination (Unit One)
• In-Class tests (Units Two and Three)

Grading Breakdown

• Case-Study Quizzes (5): 15%
• Laboratory Report (Guide/Manual: 10%, Lab data: 5%): 15%
• Mid-Term Examination: 30%
• Tests (Test 1: 15%, Test 2: 15%, Test 3: 10%): 40%

Case Quizzes

• There will be 5 short, 5-10 minute case study quizzes given in class.
• Each quiz will consist of a clinical audiogram followed by 3 multiple choice questions.
• Questions will cover describing the loss, potential causes and appropriate follow ups.
• Each quiz will be worth 3% of the final grade.

Lab Structure

• There are nine groups of 4 and one group of 3.
• Group assignments will be posted by next week.
• One member of each group will come to a training session to learn how to do the lab led by the TA.
• That person will become the trainer for the group.
• Each trainer will prepare a guide for their group (details will follow).
• Each group will complete the lab led by their trainer; support from the TA will be available if needed.
• Lab Guides and personal lab data from all four labs will be due April 9th.

Tests

• A midterm exam will be given on all material from the first half of the course (30%).
• The midterm exam will cover behavioral measures.
• The second half of the course covers physiologic measures plus any hearing aids and implant information.
• These topics will be assessed through three in-class tests.
• There will be a test on immittance and emissions (15%).
• There will be a test on electrophysiology and pediatrics (15%).
• There will be a test on hearing aids and implants (10%).
• There will be no final exam.

Activity Limitations in Audiology

• Primary activity limitation in audiology is trouble hearing or understanding speech
• Audibility issues are not the only problem, people often have trouble even when speech is audible.

Auditory Limitations: Loss of Tuning on Basilar Membrane?

• The basilar membrane and tuning are important for hearing.

Details Don't Matter For Speech

• It matters little what the order of letters is in a word, except for the first and last so long as they're correct.

Information in Speech

• Speech contains a number of Glottal Pulses (Opening and Closing of the Vocal Folds)

Harmonics, Shape and Speech

• The harmonic shape provides speech information about a particular vowel.

So What is The Real Feature for Speech

• Sinewave speech remains understandable when extracted formants and take away other speech variables.

Recognition, Formants and Temporal Cues

• Temporal cues play prominently in formants of speech.

Speech Understanding

• Experiments removing parts of the spectrum and intelligibility was measured.
• Audiometry, important part for telephone, audiometry, and more.
• Speech information is distrubuted

Articulation Index

• Fletcher divided the frequency spectrum into 20 bands.
• Those bands corresponded to 1 mm on the basilar membrane.
• That averages 114 IHC (inner hair cells) each.
• Speech feature require around 4.65mm on the basilar membrane, or ~530 hair cells.
• 5 mm on the basilar membrane = 1 octave.
• Therefore, in a normal healthy ear, there should be roughly an average of 1 feature per octave.
• Four audible octaves or four speech features are required for speech understanding.

Information in speech

• Speech perception requires audibility across a wide range of frequencies.
• Little detail is needed in any one specific frequency
• Comparison across frequency information is most important.

Articulation

• Formants or shape reflects the moment of the articulation.

Details verses General Patterns

• The auditory system mostly processes the sound information within a narrow range of frequencies.
• This fails to make logical for between the frequency channels

Tonotopicity of Processing

• Tonal maps persist in tonotopicity all the way from the cochlea through the auditory cortex.
• Across this range in the brain details must be processed to associate speech with hearing.
• These auditory processing functions are associated in the planum temporale with spectral motion of speech.

Overall Thoughts on Auditory Processing Pathhways

• Understanding speech uses general formant patterns across frequency.
• There are fine details in narrow frequency channels.

Fine Details

• The ear has precise channel information.
• Having fine spectral and temporal range allows hearing in difficult environments
• Having fine spectral and temporal range allows discrimination of sound.

Shape Across-frequency vs details

• Music can be mixed with the envelope of music or speed to create auditory chimeras.

Brain and Ear

• As it pertains to sounds, the brain is for speach and ear is for music.

Sounds and Noises

When the details become absent, speech information cannot be disentangled.

• When the details are present speech is made distinguishable.

Details Are Useful

• Details assist with disentangling voices.
• Details help with tracking the voices.
• This is called Auditory Scene Analysis
• Fundamental frequencies and source locations depend on it.
• Harmonics are the glue that hold voices together.

Consequence of hearing loss

• Hearing loss effect impacts encoding fine details and hearing in noise.
• OHC damaged (Outer Hair Cells) reduces tuning
• Phase locking is impacted.

Hearing Loss is Called Scene Analysis

• Hearing loss results in a reduced audibility
• Hearing loss results in a reduced scene analysis
• Speech information is shape information the tells us what is going on with mouth movements.

Fine Details

• Hearing is required for hearing in noise.
• Tracking voices are spacially distict from each other.
• Overlapping sounds are disentangled

Linguistics and Background Language

• There are around to 7,000 current lanaguages.
• Pitch and harmonics are important to speech and music.
• Languages in Africa and Southeast Asia use pitch distincitions.
• These facts all change the game for haring aids and implants.

Diagnosis

• Diagnosis of speech limitations occurs with pure tone tests and speech tests.
• Also, ask the patient
• Testing is a detective process.
• Example cases include different disorders like dizziness, athletes with poorer hearing, etc.

Assessment Types

• Accoustic Immittance
• Electrophysiology
• Audiometry
• Otoaccoustic testing etc.

This quiz covers key concepts in audiology, including vowel frequency distribution, activity limitation vs. participation restriction in hearing impairment, and the importance of tonotopicity in the auditory cortex. It also addresses blended learning approaches and the role of the planum temporale in auditory processing.