OAEs & AEPs - exam 2 Flashcards
objective tests
not tests of hearing
can infer if the structures are working
immittance measurements
objective tests of middle ear function & acoustic reflex pathway
OAEs are an _____ (objective/subjective) test of _____ (middle ear, cochlear,
auditory nerve and brainstem) function
objective
cochlear function
BRs are an _____ (objective/subjective) test of _____ (middle ear, cochlear,
auditory nerve and brainstem) function
objective
auditory nerve & brainstem
OAEs
otoacoustic emissions
result from both OHC responses & non-linearities on the BM
OHC movement results in sound going out of the ear (anything that moves creates sounds)
sound can be reliably elicited, measured, & used diagnostically
OAE function
OHC primary sensor for sound
can hearing loss occur w/ normal OAEs
yes
retrocochlear
OAEs only measure afferent sound
true or false
false
can be used to measure both afferent (going up) & efferent (going down) auditory system
eliciting & measuring OAEs
test probe inserted & sealed into external auditory canal
probe presents signal
mic picks up emission signal which is converted into an electrical signal & measured
spontaneous OAEs
w/out any stimulation
rare
some normal cochleae produce sounds in the absence of external stimulation
evoked OAEs
purposely introduce stimulus to evoke a response
occur in response to acoustic stimulation
used clinically
transient
distortion product
transient evoked OAEs
click introduced into the ear
amplitude of response decreases
broadband stimuli & response
distortion product OAEs
2 tones that vary in freq are presented to the ear
normal cochlea will respond by producing energy at an additional freq
vary initial freqs to span the cochlea
elicited OAE depends on the ration of stimulus freqs - response occurs at 2f1-f2
what affects OAEs
any process that affects OHC function will reduce amp of OAEs
decreased or absent OAEs may precede increased thresholds on an audiogram
SNHL & OAEs
SNHL > 30 dB HL = absent or highly decreased OAEs
OAEs may still be present w/ mild SNHL
OAEs & tymps
Type B & type As tymps generally lead to absent OAEs
if OAEs are absent, always measure tymps