Hearing And Balance Flashcards
What does the middle ear do?
Transforms acoustic energy from air to fluid
Acts as a sound amplifier
How does the middle ear accomplish its function
The tympanic membrane
Lever action of the ossicular chain (the middle ear bones)
What is otitis media with effusion also called?
Glue ear
What’s the physiological problem in glue ear?
The movement of the tympanic movement
S+S of otitis media
Conductive hearing loss
What is the impact on hearing of a small perforation
Variable
May not be a great impact
What’s the indication for repair of a perforation?
Recurrent infection
What is the maximal hearing loss that can occur due to a subtotal perforation?
If sensineural function is maintained, maximal heart g loss is 60dB
What causes otosclerosis?
Deposition of new bone in the footplate of where stapes fits in oval window
Reduces movement of stapes movement causing conductive hearing loss
Conductive vs sensorineural hearing loss
Conductive= something that stops the noise from going in. Damage in the outer or inner ear
Sensorineural=inner ear damage. Damage to the cochlea or the nerves which supply the special sense
Perilymph is high in ? And low in ?
High in potassium
Low in sodium
What is the Weber test a test of?
Lateralisation
In which ear will you hear the loudest in the Weber test?
The ear thats got the hearing loss
What does the Rhine test test?
Compares loudness of perceived air conduction to bone conduction
What does the colour red or a circle denote on audiometery?
Right
What does the colour blue or a cross denote on audiometery?
Left
How is bone conduction written in audiometry?
Open boxes
What does tympanography measure?
Measures the pressure within the middle ear and mobility of the eardrum
How does tympanography work?
Pushes pressure into the canal which makes eardrum move back and forth
What’re otoacoustic emissions (OAEs)?
Sounds given off by the inner ear when the cochlea is stimulated by sound
What happens to the outer hair cells when sound stimulates the the cochlea?
They vibrate
What do people with hearing loss not produce?
OAEs
What is a bone anchored hearing aid?
Osseous integrated screw into skull
Microphone and amplifier clip onto an abutment or attach by magnet
Sound conducts through skull to cochlea
Who would use a BAHA?
Those who’s anatomy makes it difficult to use a conventional hearing aid eg persistent otitis externa or EAC atresia
What’s the utricle?
Serves as a base for 3 semi circular canals
Utricle is sensitive to horizontal acceleration
What’s the saccule do?
Sensitive to vertical acceleration
What’s the ampullae?
Expanded areas at the end of the semi circular canals
Contain the crista
What’s the crista ampullaris?
Found in each one of the semi circular canals
3 pairs per ear in total
What does the crista ampullaris sense?
Angular acceleration and rotation
What is the stimulus for the vestibulo-ocular reflex?
Movement of the crista
What is the vestibulo-ocular reflex?
The stabilisation of gaze by moving eyes in order to compensate for head and body movement
Fixes the image on the retina for clear sight
Ix for BPPV?
Dix hallpike
What is BPPV?
Benign paroxysmal positional vertigo
What causes BPPV?
Loose otoconia move out of utricle into semicircular canals
When moving the head, the otoconia move in the canal and stimulate the cristae and provoke vertigo and nystagmus
What is nystagmus?
Rapid and involuntary movements of the eyes
In which semicircular canal are otoconia most common?
Posterior
Tx for BPPV?
Epley manoeuvre
S+S of BPPV
Acute onset vertigo
Nausea and vomiting
Is hearing loss common in BPPV?
Nope
What does the histological evidence point to with BPPV?
Viral damage of vestibular nerve rather than the sensory cells of the labyrinth
Similar to Bell’s palsy
What’s the classic triad of Ménière’s disease?
Vertigo
Tinnitus
Unilateral hearing loss
What type of hearing loss is associated with meniere’s?
Unilateral sensorineural
What can a migraine affect?
Balance
How long does the vertigo associated with Ménière’s disease usually last for?
30 mins-24 hours
