ILE HEARING AID DISPENSER EXAM
REVIEW - WRITTEN EXAM 100%
GRADED A
db loss of a perforation of TM - 10-15db loss
procedure done to fix perforation - tympanoplasty or myringoplasty
monomeric spots - looks like a hole in TM, but reflects light like a mirror. holes that have healed.
aka "mirror membranes"
average dimentions of an adult eardrum - 2.3-2.9cm in length, .7cm in diameters
pars tensa - lower 4/5 of TM and tight
pars flaccida - upper 1/5 of TM and flaccid
otis externa - "swimmers ear" - inflammation of the walls of the EAM. will not cause loss unless
swelling blocks canal. treat: warm salt water, drying it, topical antibiotics
polyps - masses of tissue that grow outward from a surface
cholesteatoma - non-cancerous tumor in the middle ear. oderous discharge. sometimes perforates
upper TM. invasions of skin into the middle ear - sac of concentric rings of protein. causes
conductive loss. most dangerous pathology.
enlarged canal - result of ear surgery. often have no ear drum or ossicular chain. need approval of
physician before fitting
tympanosclerosis - white, chalky calcium deposits caused by degeneration of tissue on eardrum,
thicking and scarring from peforations and infections
epitympanic cavity - attic of middle ear. allows air into mastoid cells of temporal bone. branches
several nerves
incudotapedial junction - top of incus to head of stapes
annular ligament - footplate of stapes that is held in the oval window
speed of sound - 700mph or 340 m/s (4x as fast through water, 14x as fast through steel)
, reflection - is an echo or a reverberation
reverberation - often in a small room, 17m or less, reverbs can mask high frequencies
echo - heard and perceived later than original sound (more than 1/10s after)
absorption - aborbs sound. can improve environments w/ reflection or reverb. better in warmth
and moist
diffraction - sharpness in the change in direction of sound, bending. high diffraction=bigger
wavelengths (low freq)
refraction - sound passes through one medium to another, change in speed and wavelength
infrasound - below audible range of 20 Hz
ultrasound - above audible range of 20K Hz
octave - anytime the frequency doubles. f(2) = on octave; f(3)= two octaves
faintest sound a human can hear - 10 ^ -16 watts/cm^2 and pressure of .0002 dynes/cm^2
threshold of pain - 1000 dynes/cm^2
when SPL levels double how many db levels increase? - 6 db
db HL expresses: - threshold levels
db SPL expresses: - voices or environmental sounds
pinna function: - gather sound, aid in localization, enahnce high freq bw 2k-5k hz
aperture - entrance to canal, first bend
isthmus - narrowing of canal
resonance frequency - between 3k-4k (or 2k-5k in other studies) range, natural boost of 10db,
when combined w/ high freq enhancement of the pinna - 15-20 db increase around 2700 hz
stenosis - narrowing of ear canal
atresia - absense of an ear canal
microtia - smaller than normal pinna
anotia - absence of one or both external ears
REVIEW - WRITTEN EXAM 100%
GRADED A
db loss of a perforation of TM - 10-15db loss
procedure done to fix perforation - tympanoplasty or myringoplasty
monomeric spots - looks like a hole in TM, but reflects light like a mirror. holes that have healed.
aka "mirror membranes"
average dimentions of an adult eardrum - 2.3-2.9cm in length, .7cm in diameters
pars tensa - lower 4/5 of TM and tight
pars flaccida - upper 1/5 of TM and flaccid
otis externa - "swimmers ear" - inflammation of the walls of the EAM. will not cause loss unless
swelling blocks canal. treat: warm salt water, drying it, topical antibiotics
polyps - masses of tissue that grow outward from a surface
cholesteatoma - non-cancerous tumor in the middle ear. oderous discharge. sometimes perforates
upper TM. invasions of skin into the middle ear - sac of concentric rings of protein. causes
conductive loss. most dangerous pathology.
enlarged canal - result of ear surgery. often have no ear drum or ossicular chain. need approval of
physician before fitting
tympanosclerosis - white, chalky calcium deposits caused by degeneration of tissue on eardrum,
thicking and scarring from peforations and infections
epitympanic cavity - attic of middle ear. allows air into mastoid cells of temporal bone. branches
several nerves
incudotapedial junction - top of incus to head of stapes
annular ligament - footplate of stapes that is held in the oval window
speed of sound - 700mph or 340 m/s (4x as fast through water, 14x as fast through steel)
, reflection - is an echo or a reverberation
reverberation - often in a small room, 17m or less, reverbs can mask high frequencies
echo - heard and perceived later than original sound (more than 1/10s after)
absorption - aborbs sound. can improve environments w/ reflection or reverb. better in warmth
and moist
diffraction - sharpness in the change in direction of sound, bending. high diffraction=bigger
wavelengths (low freq)
refraction - sound passes through one medium to another, change in speed and wavelength
infrasound - below audible range of 20 Hz
ultrasound - above audible range of 20K Hz
octave - anytime the frequency doubles. f(2) = on octave; f(3)= two octaves
faintest sound a human can hear - 10 ^ -16 watts/cm^2 and pressure of .0002 dynes/cm^2
threshold of pain - 1000 dynes/cm^2
when SPL levels double how many db levels increase? - 6 db
db HL expresses: - threshold levels
db SPL expresses: - voices or environmental sounds
pinna function: - gather sound, aid in localization, enahnce high freq bw 2k-5k hz
aperture - entrance to canal, first bend
isthmus - narrowing of canal
resonance frequency - between 3k-4k (or 2k-5k in other studies) range, natural boost of 10db,
when combined w/ high freq enhancement of the pinna - 15-20 db increase around 2700 hz
stenosis - narrowing of ear canal
atresia - absense of an ear canal
microtia - smaller than normal pinna
anotia - absence of one or both external ears
