Transcript The Evolution of Audiology

Audiometry and Hearing
Disorders
SPA 4302
Summer A 2004
The Evolution of Audiology
• “Audiology”=audire (Latin=to hear) + logos (Greek=the study of)
• Post-World War II—military aural rehabilitation centers for veterans.
• Scope of practice grew with changing technology
• Educational requirements moved from
– Bachelor’s degree
– Master’s degree (1960’s)
– Doctor of Audiology (1990’s)
• Audiologist—an individual who “is uniquely qualified to provide a
comprehensive array of professional services related to the assessment
and habilitation/rehabilitation of persons with auditory and vestibular
impairments, and to the prevention of these impairments” (American
Academy of Audiology, 1997)
Prevalence/Impact of Hearing Loss
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26 million people have hearing impairment
30 million are regularly exposed to hazardous noise levels
10 million have permanent noise-induced hearing loss
6 out of 1000 children are born with a hearing impairment
By age 6, 90% of US children have had at least one ear infection
Frequent ear infections can significantly impair speech and language
development and academic performance
• For older adults, hearing loss can impact personal relationships and
is related to overall poor health, decreased physical activity, and
depression
• Northern and Downs (2002)—for a 1 year-old child with severe
hearing impairment and average life expectancy of 75 years, the
economic burden can approach $2 million
Audiology Specialties
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Medical Audiology
Educational Audiology
Pediatric Audiology
Dispensing/Rehabilitative Audiology
Industrial Audiology
Where do we work?
• Almost 80% of audiologists ID themselves as
direct clinical service providers
• Most audiologists work within a medical
environment (physician’s office, hospitals, etc.)
• The most rapidly growing setting is private
practice (largely due to the development of the
Au.D.)
• Other settings:
– Schools, College/University, Speech & Hearing
Center, Residential Home Health Care, Industrial
Professional Societies
• American Speech-Language-Hearing Association
(ASHA)—first professional society for audiologists
(1947)
• American Academy of Audiology (AAA)—founded in
1988
• Academy of Rehabilitative Audiology
• Academy of Dispensing Audiologists
• Educational Audiology Association
• American Auditory Society
• Self Help for Hard of Hearing People, Inc.
• Alexander Graham Bell Association for the Deaf
Anatomy and Physiology of the Ear
Inner Ear
Pathways of Sound
• Air Conduction—sound travels through the outer
ear, middle ear, inner ear, and neural pathways
• Bone Conduction—sound bypasses the outer ear
and middle ear by vibrating the skull
mechanically and stimulating the inner ear
directly
AIR
CONDUCTION
Bone
Conduction
Types of Hearing Loss
• Conductive Hearing Loss
– Hearing by air conduction will be impaired, but
hearing by bone conduction will be normal
• Sensorineural Hearing Loss
– Hearing by air conduction and bone conduction will
be impaired
• Mixed Hearing Loss
– Hearing by air conduction and bone conduction will
be impaired, but hearing loss will be greater by air
conduction
Hearing Tests
• Early tests that provided little information:
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Clapping the hands
Making various vocal sounds
Ticking of a watch
Clicking 2 coins together
Tuning Fork Tests
• First used in the 19th Century
• Tuning forks emit a pure tone at a specific frequency
Schwabach Test—hearing sensitivity of a patient vs. that of the tester
Rinne Test—patient’s hearing sensitivity by bone conduction vs. by
air conduction
Bing Test—hearing by bone conduction with/out occlusion
Weber Test—lateralization of bone conducted tone:
unilateral sensorineural hearing loss-- heard in better ear;
unilateral conductive hearing loss – heard in poorer ear