CDIS 3123 Lecture Notes - Lecture 13: Ear Canal, Tympanometry, Conductive Hearing Loss
28 Mar 2017
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Functions: detects middle ear disorder, differentiates cochlear from retrocochlear disorder, used as a cross-check to pure-tone audiometry. The presence of middle ear disorder and a conductive hearing loss, although related, are independent. Middle ear disorder can be present without a conductive hearing loss. A tympanometer is often called an immittance meter or immittance bridge. Probe tone for adults is 226 hz. Probe tone for children 9 months or older is 226 hz. Probe tone for newborns and infants up to 9 months old is 1000 hz: low frequency (not as many frequencies per second) so in one second there are 1000 waves. This is used for babies because they are small and we need something small to get accurate measurements. The probe tone is delivered to a transducer that converts the electronic signal into the acoustic signal, which in turn is delivered to a probe that is sealed in the ear canal.
