air conduction
sound waves travel through the outer middle and inner ear
bone conduction
Bypasses outer & middle ear and directly stimulates cochlea.
conductive hearing loss
caused by physical damage to the ear that reduce the ability of the ear to
transfer vibrations from the outer ear to the inner ear hearing (hearing by
bone conduction is normal)
sensorineural hearing loss
damage to the cochlea, hair cells, or auditory nerve (both bone and air
conduction are impaired)
air-bone gap
the difference, in decibels, between the air conduction threshold and the
bone conduction threshold (shows conductive loss)
30-40 dB
mild hearing loss
40-60 dB
moderate hearing loss
60-90 dB
severe hearing loss
, 90 or greater dB
profound loss
typanogram
measuring middle ear function shows movement or lack of movement of
tympanic membrane through air pressure
Type A tympanogram
nice bell curve (perfect movement)
Type As (shallow)
some movement but not normal caused by otosclerosis: bony growth
around ossicular chain
Type Ad (disarticulation)
disarticulation of ossicular chain caused blow to the head
Type B tympanogram
flat line little to no movement caused by fluid or hole
Type C tympanogram
peak into negative range caused by eustachian tube dysfunction
ECV- ear canal volume
measures volume of ear canal >2 means there is a hole
stapedial muscle
tested for muscle contraction and works at 80-100db (acoustic reflex)