Audiometry and Hearing Disorders

1. Audiometry and Hearing Disorders SPA 4302 Summer A 2004

2. 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)

3. Prevalence/Impact of Hearing Loss • 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

4. Audiology Specialties • Medical Audiology • Educational Audiology • Pediatric Audiology • Dispensing/Rehabilitative Audiology • Industrial Audiology

5. 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

6. 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

7. Anatomy and Physiology of the Ear

8. Inner Ear Middle Ear Outer Ear

9. 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

10. AIR CONDUCTION

11. Bone Conduction

12. 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 (Outer/Middle Ear) (Inner Ear/Neural) (Both)

13. Hearing Tests • Early tests that provided little information: • Clapping the hands • Making various vocal sounds • Ticking of a watch • Clicking 2 coins together

14. 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