Audiology Flashcards
(31 cards)
what is pure tone audiometry
non invasive hearing test that measures a persons ability to measure different sounds, pitches and frequencies
what is the hearing threshold
quietest sound that an individual can hear across a range of different frequencies
how are pure tones described
frequency, amplitude, phase and duration
how is pure tone amplitude quantified
decibels
Red is for right/left
red = right blue = left
what are the 3 transducers used to present tone
headphones
insert earphones
bone conductors
what does air conduction assess
whole hearing pathway
what does bone conduction assess
inner ear
bypasses external and middle ear
what are the different levels of hearing loss
mild
moderate
severe
profound
what is a normal reading
anything above 20
what is the symbol for right air conduction
red circle
right is never wrong
what is the symbol for left air conduction
blue cross
what is the symbol for unmasked bone conduction
black triangle
define threshold for mild hearing loss
20-40
define threshold for moderate hearing loss
41-70
define threshold for severe hearing loss
71-95
define threshold for profound hearing loss
95+
why is masking done in audiometry
it is not always certain that the intended test ear is the one detecting the sound. The better non-test ear may detect the signal easily.
how is masking done
masking noise is introduced to the better ear to prevent it from picking up any pure tone
how many rules of masking are there
3
in general what are the rules of masking
- if there is a big difference between R + L ears
- unmasked BC is better than AC
- if rule one has not been applied
BC can be above the AC threshold, true or false
FALSE
features of CHL on audiogram
significant air bone gap present
BC within normal limits ie above 20 otherwise it is a MHL
causes of CHL
ear infections
glue ear
perforated ear drum
