Hearing tests Flashcards
What are tuning fork tests used to differentiate between?
Sensorineural and Conductive hearing loss
What is Rinne’s test?
Put vibrating fork next to ear and on bone behind
Conductive hearing loss - BC>AC (Rinne’s negative)
Sensorineural hearing loss - AC>BC if heard (Rinne’s positive)
Rinne’s positive is normal as Air conduction should be greater than bone conduction
What is Weber’s test?
Put vibrating fork on the middle of the patients forehead. Should sound equal.
Sensorineural - localise away from side of damage
Conductive - localise towards side of damage
Why does conductive hearing loss localise to the side of damage in Weber’s?
Conductive loss block out background noise so vibrations amplified
What is a pure tone audiogram?
Test used to assess threshold of hearing at various frequencies
Where should a pure tone audiogram be conducted?
In a sound proofed booth
How is a pure tone audiogram performed?
Tones are played at different frequencies to each ear. The quietest tone that can be reliably heard is marked on the audiogram. Higher the decibel number, go down on y axis - louder noise. Higher the line, better hearing
What is considered normal hearing?
Anything less than 20dB
How do you test air and bone conduction in a pure tone audiogram?
Air - headphones
Bone - Bone conductor on mastoid
How are conductive and sensorineural hearing loss seen on pure tone audiogram?
Conductive - normal bone conduction, reduced air conduction
Sensorineural - reduced air and bone conduction
How would you investigate a unilateral sensorineural hearing loss?
MRI to look for lesions on the pathway
What is presbycusis?
Hearing loss due to aging
What is a tympanogram?
Test to measure compliance of tympanic membrane
Give info about tympanic membrane, middle ear and eustachian tube function
How are the results of a tympanogram plotted?
y axis - compliance
x axis - pressure (daPascals)
When does compliance of the tympanic membrane peak?
pressure in external ear canal = middle ear
