first step
otoscopic evaluation
otoscopic eval
- make sure ears are clear of wax, foreign body, drainage from middle ear infection
- if able to visualize TM, make sure its not red, irritated, no perforations
- can you see cone of light?
middle ear eval
if EAM is clear, perform tymps/immitence testing
tymps
allow us to examine the middle ear functioning by using measures of pressure and movement of middle and outer ear
3 principles of tymps
pressure (air pressure behind ear drum)
compliance (how much the TM moves)
volume (how much space is in the inner ear)
tymp probe tip
- placed at opening of ear canal
- has air pump to change pressure
- sends out 220 hz tone and also has mic to record how ear reacts to tone
- pressure is varied from -200-200 hz
tymp pressure
- values are indicative of amount of pressure in middle ear cavity
- measurements made in decapascals
- normal middle ear cavity maintains a pressure that approximates normal atmospheric pressure
tymp compliance
- values indicative of amount of mobility
- measured in cubic cm or mm
what can cause change in compliance?
- scarring
- hole
- fluid
- ossicles fused together (otosclerosis)
what if compliance is too high?
- disarticulation of ossicular chain
- hypermobile drum (stretched out over time)
tymps volume
- measures estimated volume of ear canal from probe tip to the drum
- range of normal varies
large volume is suggestive of…
patent/open tubes
small volume is suggestive of…
clogged tubes/ not functioning properly
tymps with normal pressure
Ad
As
A
Ad
high compliance normal pressure
- compliance greater than 2.0
- may show hearing loss
As
limited mobility/compliance, normal pressure
- compliance below .25 for child
- below .3 for adult
-often accompanied with hearing loss
A
normal
C
looks like type A, but pressure is abnormal
- pressure less than -150
- reflects retraction of ear drum and a system of negative pressure in middle ear space
- can be caused by partially blocked e-tube
- often seen with allergies or resolution of ear infection
B
- flat pattern, no peak at all
- ear canal volume is important
- if large volume, need to see if person has perforated tubes
- if small volume, maybe wax
- OFTEN associated with conductive HL
reflex
occurs in response to high intensity sounds
- works during gunshot, alarm
- used clinically to distinguish between cochlea vs retro cochlea and malingering
