Week 2 - C - Pure tone audiometry and tympanometry Flashcards
When assessing the nature and degree of hearing loss in a child, what is carried out? This is done after rinnie and weber’s test
Carry out pure tone audiometry (PTA)
PTA is a measure of an individuals hearing sensitivity for calibrated pure tones What are the three main transducers that are used to present sound to an individual in PTA?
Headphones Insert earphones Bone conduction
Which of the three transducers is used to test air conduction?
Headphones or insert earphones Assesses the entire auditory pathway
How is bone conduction assessment carried out in PTA?
Uses a bone conducter and bypasses the external and middle ear stimulating the cochlea directly
What are the axis of the audiogram graph?
The x-axis is increasing frequency from low pitch to high pitch
The y-axis starts at -10 then goes to 20 which is the norm, then increasing decibels as you go down for the amount of hearing loss
What is considered normal hearing for a person? (in decibels)
Being able to hear sounds below 20decibels
If a patient cant hear sound between 25 and 40 decibels, what type of hearing loss is this?
Mild hearing loss
What is severe and what is profound hearing loss?
Severe hearing loss is being unable to hear sound between 71 and 90 decibels
Profound is being unable to hear sound 91+ decibels
https://s3.amazonaws.com/classconnection/403/flashcards/11907403/jpg/picture1-15A2E8F149C5DA5B3E9.jpg
Moderate loss is between 41 and 55 Moderately severe is between 56 and 70 decibels
On a basic audiogram, what ear is marked as red and which as blue?
Right ear is red Left ear is blue
O =Air Conduction Right X = Air Conduction Left What is bone conduction marked as on an audiogram?
Bone conduction is a black triangle
When a difference between ear thresholds occurs, what is used to obtain the true hearing threshold?
Masking
In masking a narrow band noise centred around the test frequency is introduced into the non-test ear. This noise “occupies or distracts” the non-test ear and allows the test ear to respond the pure tones at the true threshold
- Red filled circle = ?
- blue filled hour glass = ?
- [ = ?
- ] = ?
filled circle is masking right ear to test the left ears true threshold
What does a sensorineural hearing loss on audiogram look like?
It is seen when there is no difference between bone conduction and air conduction on the audiogram
Sensorineural hearing loss is a result of damage to the cochlea (the hairs inside) or damage to the nerve for hearing Damage to the cochlea occurs naturally as part of the ageing process, age-related hearing loss is known as?
Presbycusis
There are other causes of damage to the cochlea such as ototxic drugs Name two? What infectious disease can cause damage to the cochlea?
Gentamicin eg ear drops for otitis externa
Chemotherapy
Rubella
When is conductive hearing loss seen on the audiogram? What are examples of causes?
When there is a significant gap between air and bone conduction thresholds
Middle ear infection, glue ear, perforated eardrum
Can be seen on an Audiogram as at parts there is a significant gap between air and bone conduction thresholds but bone conduction thresholds are not all within normal limits What is this?
Mixed hearing loss
Tympanometry sets compliance against pressure of sound applied in ear canal (x-axis) Is this graph normal or abnormal?
Type A - normal
Type B - fluid behind the ear causing bad compliance to pressure or tympanic membrane perforation
Type C - Represents negative pressure in the eardrum eg resolving or preceding an otitis media, eustachian tube dysfiunction
Type As (Astiff) - commonly seen in fixation of the ossicular chain suggesting limited mobility of the t.membrane
Type Ad - high compliance - disruption of ossicular chain
