Audiology Test 3

Which muscles are involved in the acoustic reflex?

two small muscles, the tensor tympani muscle and the stapedius muscle

the stapedius muscle contracts, causing the TM to stiffen, but the TT’s role is unknown

Acoustic reflexes occur in response to what stimulus?

intense sound

Define Acoustic Reflex Threshold

the lowest level at which an acoustic reflex can be obtained

How do SOAEs differ from EOAEs?

SOAEs occur in the absence of stimulation, and EOAEs occur during or directly after stimulation

List 2 types of EOAEs

• transient EOAES - produced by brief acoustic stimuli, such as clicks

• distortion-product OAEs - when the cochlea produces energy at additional frequencies when two primary tones that vary in frequency by several hundred Hz are presented

What is indicated by the presence of an EOAE?

that there is very little or no CHL caused by ME abnormality and that the responding regions of the cochlea are normal or mild HL (if SNHL, the problem is not in the cochlea)

What does ABR stand for?

• auditory brainstem response

• early AEPs occurring in the first 10-15 milliseconds after introduction of a signal, originating in the VIIIth cranial nerve

Describe 2 uses for the ABR test (p. 184)

to test audiological function or neurological function

SOAEs

• spontaneous otoacoustic emissions - normal cochleas producing sounds in the absence of external stimulation

EOAEs

• evoked otoacoustic emissions - occurs during or immediately following acoustic stimulation