ear 1/2 Buzz info Flashcards
(55 cards)
what are the sensory hearing loss causes?
-noise
-head trauma
-systemic dx
-ototoxic drug
infxn:
-Meniere syndrome
-labyrinthitis
Auditory and vestibular systems use:
both hair cells to transduce mechanical forces into action potentials.
what are neural hearing loss causes?
-acoustic neuroma
-multiple sclerosis
-auditory neuropathy
infxn:
-Meniere syndrome
-labyrinthitis
Hair cells are located in
a fluid filled sensory organ called the membranous labyrinth.
The cochlea is the =
auditory component.
-afferent neurons exit cochle→ form auditory nerve
The otoliths organs utricle/saccule and the semicircular canals is the →
vestibular components of labyrinth → CN8
-Pitch (tone):measured in
HERTZ : Higher frequency= higher pitch
-the ear usually receives higher pitches @ the beginning and the apex receives the lower pitches
Intensity (loudness) : measured in
DECIBELS → amplitude
Sound travels through
ossicles→ sound vibration→ vibration in fluid mov’t that stimulate hair cells→ action potential
Hearing loss: 2 types
Most common due to :
Sensorineural (SNHL)
Conductive (CHL)
CERUMEN IMPACTION (WAX), ETD ( CHL), age related hearing loss (SNHL)
Sensorineural Hearing Loss (SNHL):
Etiology:
-genetic make up influences all causes of hearing loss
-hair cells of cochlea
-cochlear branch of CN8 ( damage to the nerve)
-areas if the brain that process auditory information
Presbycusis:
Etiology:
sx:
most frqt cause of sensory hearing loss
–progressive, predominantly high frequency and symmetric
Etiology: noise trauma, drug exposure, genetic predisposition
SX: loss of speech descrimination
-sounds > 85 dB = cochlea injury
Ototoxicity:
Cause DEATH OF SENSORY HAIRS (auditory and vestibular)
Most common ototoxic meds:
-aminoglycosides (neomycin, gentamicin)–> avoid in ototoxic ear drops in TM
-loop diuretics
-platinum based antineoplastic agents (cisplatin)
-ASA/NSAIDS
Sudden SNHL:
Dx:
-idiopathic sudden loss of hearing in ONE EAR
->20 yrs old
Diagnosis:
-Audiogram and MRI
Congenital and Genetic Hearing loss:
Congenital- present at birth
Genetic HL- discovered later
Most acquired prenatal cause:
Specific PE findings associated with :
-intrauterine infxn ( CMV)
-pre auricular pits and tags
-lateral displacement in the inner corner of the eyes
-hetero iridis
PE abn → risk abn. Of hearing
Conducting Hearing Loss (CHL):
- external or middle ear dysfunction
Conducting Hearing Loss (CHL):
4 main mechanisms= impairment of the passage of sound vibrations to the inner ear:
-obstruction: cerumen ( wax) impaction
-mass loading: middle ear effusio, ETD ( not allowing ™ to move)
-stiffness: scarring of ™
-discontinuity-oscillar disruption
Otosclerosis:
Etiology :
Sx:
PE:
Diagnostic:
abnormal overgrowth of the footplate of the stapes→ conductive hearing loss
Etio: autosomal dominant disorder of abnormal resorption and deposition of the bone in the otic capsule.
Sx: gradual progressive conductive hearing loss 20s-40s, initially low frequency hearing loss
PE: normal otoscopic exam, Weber and rinne (CHL)
Diagnostic:
Audiometry and CT temporal bone
Gross auditory Acuity :
- pt in a quiet room would repeat aloud the words presented in a soft whisper.
512 hz tuning fork is useful in differentiating conductive from sensorineural losses.
Weber test:
CHL:
SNHL:
Normal:
tuning fork is PLACED ON TOP PT HEAD and sound is interpreted by pt
Normal= sounds the same bilaterally
CHL= sounds louder in the affected ear
SNHL= sounds louder than normal in the non affected ear
Rinne test:
normal:
CHL:
SNHL:
tuning fork is placed on the mastoid bone then at the entrance of EAC.
Normal air conduction > bone conduction : can hear the sound in both places
CHL= Bone conduction > air conduction: CANNOT hear the sound @ EAC
SNHL= air conduction > bone conduction: normal
