Quiz 2 Flashcards
OAE?
Otoacoustic Emissions or cochlear echoes
First type of OAE’s measured in humans?
TEOAEs or transient evoked otoacoustic emissions
Who measured the TEOAE’s?
David Kemp
Actions potentials are …
“ALL OR NONE” = 100% response
Characteristic Frequency
frequency requiring LEAST amount of stimulus INTENSITY to provide a response from the nerve fiber
Afferent pathways of the CNS are…
ASCENDING pathways
Efferent pathways of the CNS are…
DESCENDING pathways
ratio of nerve fibers in the afferent pathway to efferent pathway is…
100 nerve fibers to 2 nerve fibers
Auditory brainstem response (ABR) include:
recorded RELIABLY, ESTIMATE hearing, assists in detection of problems in the path of the auditory CNS
define threshold
lowest level at which sound can be detected 50% of the time
normal hearing person’s best (lowest) thresholds are in what range?
2,000 to 4,000 Hz range
what is the range of audibility
20 - 20,000 Hz
define masking
ability of one acoustic single to OBSURE the presence of another signal so it cannot be DETECTED
define binaural processing
one of the key functions of the CNS. it allows us to combine/INTEGRATE the neural info from BOTH ears
binaural processing is necessary for…
LOCALIZATION of sound & the ability to HEAR in noisy situations
genetic transmission of hearing loss is due to what 3 things:
AUTOSOMAL dominant inheritance (non-sex linked) , AUTOSOMAL recessive inheritance and SEX linked inheritance (X-linked)
hereditary factors make up what percentage of all auditory disorders?
50%
define endogenous
a trait or disorder that arises from the individual’s GENES
define exogenous
a trait of disorder that is NOT attributable to GENETIC causes
define congenital
a trait or disorder that is present at birth
congenital hearing loss may or may not be what?
hereditary
5 causes of outer ear disorders:
deformity of the PINNA, COLLAPSED canals, CERUMEN/foreign bodies, external OTITIS, or cysts and TUMORS ((PCCOT))
define otosclerosis
common cause of hearing loss for people in their 20, 30 and 40’s
what is otosclerosis caused by?
buildup of SPONGY BONE that immobilizes the STAPES FOOTPLATE
in what two ways can otosclerosis be treated?
STAPEDECTOMY (surgery) or a HEARING AID
define cholesteotoma
growth of skin and debris associated with perforation of eardrum
define facial paralysis
facial nerve crosses through the middle ear
define perforation of the tympanic membrane
hole in the eardrum
define tympanosclerosis
plaque that forms on eardrum and ossicles causing stiffening
define adhesive otitis media
glue ear
what percentage of children have otitis media?
75-95% will have at least one episode by the age of 6 years
what is the most common disease of childhood?
otitis media
with who and when does otitis media occur more often?
in males and in the winter & spring
what 2 ways alleviate otitis media?
antibiotics and surgery (MYRINGOTOMY & ADENOIDECTOMY)
5 risk factors for hearing loss among newborns:
in utero infections (STORCH- syphillis, toxoplasmosis, other, rubella, cytomegalovirus, herpes simplex), low birthweight, family history of hearing loss, evidence of a syndrome and craniofacial abnormalities
what is a common cause for unilateral hearing loss that occurs after birth (post-natally)?
mumps
what is a common cause for bilateral hearing loss that occurs after birth?
measles
what is retrocochlear pathology?
damage to the nerve fibers along the ASCENDING auditory pathways from the internal auditory MEATUS to the CORTEX
what causes retrocochlear pathology?
due to a TUMOR, MS or cerebral vascular attack (CVA)
define presbycusis
hearing loss associated with aging, HIGH frequency, sensorineural hearing loss, progression is usually more pronounced in men that in women
Noise Induced hearing loss (NIHL) is characterized by what 3 things?
audiogram with a 4K NOTCH configuration, a permanent SENSORINEURAL hearing loss in the HIGH frequencies and near normal hearing in the LOW frequencies, and distraction of OUTER hair cells in the cochlea in the BASE with little or no inter ear damage near the APEX
ototoxic drugs cause what?
usually cause high frequency hearing loss
what are the 2 primary components of the outer ear?
the pinna and the external ear canal
what does the concha do?
serves to collect and direct sound to the external auditory meatus
what is the auricle?
the pinna
what is the external auditory meatus?
opening to ear canal
what 2 structures of the outer ear are responsible for resonance?
the concha and the ear canal
what divides the outer and middle ears?
tympanic membrane (ear drum)
what is the eustachian tube?
connect the NASOPHARYNC to the middle ear, it is usually closed except when YAWNING or SWALLOWING
what does the eustchian tube do?
allows FLUID to drain from the middle ear and allow us to EQUALIZE to equalize pressure in the middle of the year (ear pops when going up in a plane or up the mountain)
what does the helicotrema do?
filled with perilymph fluid and connects the scala tympani and the scale vestibuli
what separates the scala tympani and the scala vestibule?
the scala media which is filled with endolymph flud
what is the organ of corti?
the sensory organ of hearing in the scala media
where is the organ of corgi?
basilar membrane in the cochlea
what is the order of ossicles?
malleus, incus and stapes ((HAS) (MIS))
what are the 4 functions of the outer ear?
distinguish ELEVATION of sound, distinguish if sound is in FRONT, protects from FOREIGN bodies
how much does the concha enhance?
5000 hz
how much does the external auditory canal enhance? (ear canal)
2500 hz
what kind of frequencies are amplified by the outer ear?
high frequencies for conversational speech
where do sound vibrations travel?
through the ossicles, to the footplate of the stapes in the oval window, inner ear
loss of sound going from air to fluid through which 2 primer mechanisms?
areal ratio and lever system
when the ear is stimulated by sound….
the oval window moves in, and the round window is moved out
when the ear is stimulated by fluid….
the round window is moved out, and the oval window is pushed in by the stapes footplate
how are the nerve cels arranged?
tonotopically
the base of the cochlea contains what frequencies?
high
the apex of the cochlea contains what frequencies?
low
