CGSC379 Lecture Notes - Lecture 6: Immittance, Acoustic Reflex, Tympanometry
4 Nov 2018
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Do not require a voluntary response from the patient. Can help pinpoint the site of dysfunction. Are used as cross checks to verify or validate other test results (can"t fake it) Visual inspection of the ear via otoscope. Verify that ear canal is not occluded. Check for signs of trauma or infection. Become familiar with shape and size of patient ear canal (where test probes go, size tip. Ease of opposition to transfer of acoustic energy. Dapa (decapascals) units of ear canal pressure. Requires use of a probe tip inserted in ear canal creating airtight seal. Mechanically changes air pressure in ear canal. +200 to -400 dapa (as compared to atmosphere) Measures how sound bounces back at microphone as pressure changes. Pressure measured in dapa on x axis. Immittance measured in cm3/mmho on y axis peak immittance is point of maximum displacement. A - normal, peak compliance between +100 and -100 dapa.
