Beginning Stuff
what parts of ear affected in conductive loss vs sensorineural loss
conductive- outer ear and middle ear
sensorineural- inner ear and auditory nerve
type a tympanogram
ear drum is moving, at 0, nice bell curve
after u get the type in the tympanogram, the probe emits a loud sound where air was introduced before in the external auditory meatus. the 1st sound is presented at ___ dB and what should contract ?
80 dB and stapedial muscle should contract in response to sound. Acoustic reflex its called when stapedial muscles contracts in response to the sound. if not picked up at 80 go to 90 if not then 100 if not then its over and itll say acoustic reflex absent. 10% of ppl just dont have it but dont have issues hearing.
BOA
behavioral observation audiometry, unscientific, make noise and see if baby respond, no equipment but hands or callibrated noise makers at 40 dB, if show awareness of sound then we know its not a hearing loss greater than moderate, so either normal, mild, or brink of moderate
whats in the inner ear
degrees of hearing loss what are they
within normal limits-<30
mild- 30-40
moderate- 40-60
severe-60-90
profound- 90+`
type B tympanogram
indicates ear drum is immobile, can be caused by ear infection/fluid buildup, or perforation of tympanic membrane (hole in ear drum), probe in ear not getting response from TM
why would u have an absent acoustic reflex
Bells palsy (facial nerve cranial nerve VII paralysis) or acoustic neuroma. facial nerve innervates stapedial muscle
VRA
visual reinforcement audiometry, for kid who comes for a hearing test, usually preschool or kid w developmental delays, child kept busy playing w toys, other aud presses button sound comes on and toys light up in smoky glass box, condition child so they hear sound and see toys light up, make tone quieter each time so can find threshold at each freq, eventually press button for sound into booth but no toy, present sound very low to see if child looks for toy to light up
how do we test vestibular system
caloric test, warm water drops then cold and look for eye movements bc occipital nerve and vestibular nerve are closely connected and will see flutter of eye which is NYSTAGMUS
whats the air bone gap tell us
if theres a gap its a conductive loss its the dif between the air conduction threshold and the bone conduction threshold.
if theres no gap and they match its a senorineural loss
ECV
ear canal volume, measures volume of ear canal,in Type B ECV can determine if cause is the hole in the ear drum, if ecv greater than 2, take measure of whole middle ear space bc indicative of hole
why do we masking and whats in clear plastic flexible fiber tube for cochlear implant
for unilateral loss to keep better ear busy, its narrowband noise (center of noise around same as tone presented) put in better ear, to get more accurate threshold for poorer ear
every so often is a black dot, that is the electrode purpose is to stimulate auditory fibers, also arranged tonotopically, placed on BM in scallomedia to replace hair cells.
OAE and ABR
otoacoustic emissions screening, sound enter ear through probe and cochlea echoes back, if not echo back tell parent didnt pass, come back in few weeks bc might just be excess of fluid, if no pass second time, do ABR auditory brainstem response which is when electrodes placed on baby's head and record auditory nerve reaction to sound, click sound in babys ear through headphones too and if nerve in tact it will respond to stimuli and electrodes record response
when issue w difficulty processing language its beyond the cochlea (retrocochlea).
first station from aud nerve to aud cortex is _.
auditory cortex is where we_.
Central auditory processing disorder?
analog vs digital hearing aid?
cochlear nuclei
make sense of coded msgs
determine whats going on in pathways to aud cortex
digital in canal aid for adult bc process incoming sound in real time and for technology, bluetooth, and can program remotely
for the air bone gap to actually mean conductive loss tho
needs to be more than 5 dB difference
Type As
SHALLOW, indicates otosclerosis: bony growth in middle ear common in women
interaural attenuation
expense of hearing aids. ppl can buy over the counter but not for _ or _ hearing loss
classroom amplifaction systems. or can use loud speaker or mic. what's the goal?
whats the inverse square law?
40 dB lost in travel through cross hearing
severe or profound
to improve the signal(teacher) to noise(ambient) ratio, theres electroacoustic issues
in class, for every double distance from speaker there are 6 dB lost
if ur a baby born in hospital u need what before discharge & by __months of age we know if a baby is deaf & reasons for deaf baby
hearing screened, 3 months of age, leading cause of senorineural hearing loss is CMV (cytomeglavirus) which is a disease acquired in utero from mom, herpes based usually from changing diapers of other kids in fam or saliva, meningitis can wipe out cochlea, for meningitis usually hearing aids but if severe/profound and want cochlear implant have to decide quick bc theres a bony growth in the scallomedia in cochlea and it might become impossible
auditory fibers, which are also arranged tonotopically, high freq on outside of cable, low freq insulated in the middle, when the fibers come together its the auditory nerve
what does tympanograms test
assesses middle ear function
Type AD
DISARTICULATION of ossicular chain (bones). two parallel lines never mean. causes: blow to head, victim of assault
__ in 1,000 babies born will have significant hearing loss, most are born w 2 __ parents bc of recessive gene/genetic factors, most will choose ___ bc_
1, hearing, cochlear implants bc it provides auditory channel to brain and its an option now.
-small population now in deaf schools and lots closed, early id changed everything esp early intervention
babies wear what kind of hearing aid and why
Behind the ear hearing aid (BTE) bc it is durable and earmold can easily be changed, babies ears need to change earmold often bc babies ears grow like every 3 months, if dont change will hear feedbackkk
tell me everything yk abt inner ear and traveling wave
cochlea is snail shaped shell and makes 2.75 turns around its axis and lined with basilar membrane which houses the organ of corti and has hair cells embedded. stapes knocks on oval window and sets the wave into motion, traveling wave shears/bends tops of cilia. hair cells arround in BM tonotopically. sounds are electrochemical energy in inner each. beginning, basal end- high frequency sounds, end, apex-low frequency cells. Tonotopic organization. high cut off low pass filter.