ears - general deafness Flashcards
biggest –> smallest ear bone
malleous, incus, stapes
what muscle + nerve innervation opens eustachian tube
Tensor veli palatini (CNV3) + levator veli palatini (CNX) - by constricting muscles of soft palate
how is sound transmitted to brain
E.coli - 8th nerve , cochlear nucleus , sup olivary complex , lateral lemniscus, inferior colliculus
where is sound processed in brain
left superior temporal gyrus
what level of sound is normal on an audiogram
anything above 20dB
what colour on audiogram indicates right ear
red
what colour on audiogram indicates left ear
blue
what symbols on audiogram indicate air vs bone conduction
<> = bone // O or X = air
what would a sensorineural audiogram show
loss of both air and bone conduction
what would a conduction audiogram show
only loss of conduction hearing
Rinnes + webers test in sensoirineaural hearing loss
rinnes (normal) = air conduction > bone conduction // webers = localised to UNAFFECTED ear
Rinnes + webers test in conductive hearing loss
rinnes: air conduction > bone conduction = conductive hearing loss // webers = lateralised to AFFECTED ear
causes tinnitus
mernieres // otosclerosis // sudden onset sensorineural hearing loss // hearing loss // drugs // ear wax
what meds can cause tinnitus
aspirin // NSAIDS // aminoglycosides eg gent // furosemode // quinine
what type of tinnitus requires further imaging
pulsatile (may be vascular) // non-pulsatile but unilateral +/- neuro signs
imaging in tinnitus
MRI = non-pulsatile // MR angio = pulsatile
what is Presbycusis
high frequency, bilateral hearing loss, age related
RF for Presbycusis
ateriosclerosis // diabetes // lots of noise exposure // drugs eg salicyltaes, chemo
symptoms Presbycusis
can’t understand speech as well // worse with background noise
otoscope, tympanometry, audiometry Presbycusis
otoscopy = normal // tympanometry = normal middle ear + hearing loss // audiomoetry = bilateral sensorineural hearing loss
what type of hearing loss is noise induced
sensorinearal
frequency of noise-induced hearing loss
dip at 4Khz
which children are suitable for a cochlear implant
children severe hearing loss +/- difficulty developing auditory skills
causes of severe-to-profound hearing loss children
genetic // congenital infection (CMV, rubella, varicella) // idiopathic // infectious eg meningitis
which adults are suitable for a cochlear implant
who have severe-to-profound hearing loss +
have triad hearing aids for at least 3 months with no improvement
causes severe-to-profound hearing loss adults
viral // ototoxic // otosclerosis // menieres
what must be intact for cochlear implants to work
surviving spiral ganglon neurones
complications cochlear implant
infection // facial paralysis // CSF leak // meningitis
contraindications cochlear implant
lesion of CN VIII or brainstem // chronic otitis media // tympanic membrane perforation // cochlear aplasia
