CGSC379 Midterm: Exam 2 Study Guide
21 Aug 2018
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Acoustic immittance what you admit in, allow through. Immittance: cm3 or mmho: units of ear canal pressure: dapa. Primary components of the equipment: transducer, air pump, manometer, microphone. < 0. 3: the probe tip may be against canal wall. > 2. 0: may be measuring beyond the canal, esp. in a child. 0. 4 1. 0: normal for children younger than 7. 0. 6 1. 5: normal for adults: measure taken at +200 dapa. Acoustic reflex testing measures the acoustic reflex arc: stapedius contracts to loud sound, not a test of hearing, acoustic reflex threshold = 70 100 db spl, used to diagnose retrocochlear pathologies, can be measured: Ipsilateral primarily tests afferent system: contralateral primarily tests efferent system, occurs at peak pressure of eardrum, typically tests 500, 1k, 2k and 4k, acoustic reflex decay testing, tone continues for 10 seconds. If reflex decays by 50% or more abnormal.
