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HISTORY OF HEARING TESTING. Audiology. Audio - Latin…to hear, pertaining to hearing Logy - Greek…logus…science Therefore the science of hearing and hearing disorders. Facets of audiology. Discovery Evaluation Rehabilitation. Lineage of Audiology.
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Audiology • Audio - Latin…to hear, pertaining to hearing • Logy - Greek…logus…science • Therefore the science of hearing and hearing disorders
Facets of audiology • Discovery • Evaluation • Rehabilitation
Lineage of Audiology • Originated during and just after WW II (1945-46) • Originally audiologists were SLP’s or ENT’s • Father of Audiology is Raymond Carhart (he and Norton Canfield coined the term “audiology
Reason for the field of Audiology • The government became concerned with hearing disorders when VA hospitals had military with hearing problems due to: -direct injury—gunshot, shrapnel -disease—jungle rot -acoustic trauma—high intensity noise (cannons,guns,etc) -emotional disorders - “shell shock” (protective device) • Aural rehabilitation hospitals opened all over the nation and were interested in: -conservation of hearing -habilitation and rehabilitation programs -diagnosis (Dx) of hearing loss related to medical problems -educational placement and programs for the hearing impaired
Academic Qualifications for Audiologist • BA/BS in Communicative Disorders or equivalent • MA/MS in Audiology • Pass national written examination (formerly NESPA) • Complete Clinical Fellowship Year (CFY) • Certificate of Clinical Competence in Audiology (CCCA) • State License (usually CCCA + fees) • Au.D. or equivalent will be needed by 2007 • Ph.D. and FAAA is optional at this time
Other Hearing Health Professionals • Otolaryngologist • Hearing Conservationist • Hearing Aid Specialist • Audioprosthologist • Audiometrist
Professional Opportunities for Audiologists • Teaching • Clinical • Research • Administration
Hearing Tests and their Development (non-audiometric) • Watch tick • Coin-click • Conversational voice • Noise makers • Tuning fork tests (Demonstrate using tuning fork) • Schwabach Test (also called the time threshold test) • Rinne Test • Bing test • Weber
Pure Tone Audiometry • Normal hearing (intensity) = 0—25dB (ANSI) • We hear 20—20,000 Hertz (frequency) • We only test 250—8,000 Hertz (Hz) • 250, 500, 1000, 2000, 3000, 4000, 6000 & 8000Hz are the individual frequencies at which we test by AC • 250, 500, 1000, 2000 and 4000Hz are the frequencies for BC • Quiet environment needed (otocups, insert phones and booths • Occlusion effect—the increase of loudness of pure tones at 1000 Hz or lower. Happens in normal, sn—not in conductive losses. • Sweep check vs. threshold testing
Performing the Pure Tone Test • Check calibration of audiometer • Otoscopic inspection (wax, collapsed canal, drainage etc.) • Patient instructions • Question: Which is your better ear? • Hairdos, wigs, glasses and earrings • Correct placement of earphones (TDH 39) • Correct placement of the patient
Performing the Pure Tone Test (continued) • Pulsed or continuous signal • Present tone with about 1 second duration • Be aware of eye contact • Watch out for “rhythm system” • Red, right, round. Blue X’s for left (AC) • Bone conduction (BC) thresholds and symbols • Masking for AC and BC • Maximum output at each frequency
Patient Responses • False negative • False positive • Validity vs. reliability • Down 10; up 5 rule • Determine threshold • Test re-test reliability • Pure tone average (PTA) • Tactile responses (cutile) • Cross hearing and interaural attenuation (IA) AC & BC
Masking • Narrow band • White noise (broad band or wide band noise) • Effective masking • Over masking (OM • Speech noise • Complex noise • Other masking (saw tooth, pink noise etc.) • Plateau Method
Calculation of Percentage of Hearing Loss • Average thresholds at 500, 1K, 2K and 3KHz • Subtract 25 dB • Multiply X 1.5 for each ear = % of loss per ear • Binaural loss %’age = better ear X 5 + poorer ear %age divided by 6 = binaural percentage loss
Audiograms • Table audiogram • Graph audiogram