steps to record OAEs
step 1-3
1. otoscopy, instruct listener, choose protocol, place probe tip with seal, test in quiet room
2. choose test type: DP or TE
3. enter demographic data
general diagnostic frequencies
500-8000 Hz
X axis
f2 frequency in Hz
noise floor may show
95th percentile noise level for normal adults
physiologic noise
blood flow, respiration, body movements, chewing, talking, crying
step 4 and 5
monitor stimulus levels
monitor noise levels
infant hearing screening frequencies
2000-4000 Hz
Y axis
amplitude of OAE response in dB
where do we want noise floor
below 95th percentile
NF amplitude should be at or below -10 dB SPL
ambient noise
room from air condition, tester noise
step 6
replicate OAE measurement in same ear
L1 is
65 dB
red circles
green triangles
blue lines
gray lines
red circles: OAE response amplitude as function of f2; reflects cochlear health on basilar membrane corresponding to f2
green triangles: noise floor
blue lines: normal OAE amplitude range
gray lines: normal noise floor range
equipment noise
decrease by?
electrical (lights)
decrease by turning them off
step 7-8
change to other ear
replicate OAE measurement in other ear
L2 is
55 dB
top 95th percentile
if OAE exceeds this for those with loss, then there is less than a 5% chance the OAE came from ear with loss
decrease physiologic noise
instruct to remain still, provide distractors for young kids, children asleep, stabilize cord to prevent movement of probe, increase amount of signal averaging during recording
step 9
change protocol as indicated
frequency ratio
1.2
bottom line is 5th percentile
if OAE is below this with normal hearing, there is less than a 5% chance it came from an ear with normal hearing
decrease ambient noise
close test room door, position pt far from equipment, may be possible to locate pt in booth and OAE equipment outside the booth, turn pt so test ear is away from equipment, re-seal OAE probe-tip deeper in ear canal, increase amount of signal averaging during OAE recording