OAE: stimulus
click at 3000 and 36000 Hz
OAE: response
large waves (high amplitude)=good hearing
small waves (small amplitude)=poor, something wrong
absent=cochlear hearing loss greater than 40-50 dB
Outer Ear Pathologies
microtia, atresia, anotia, external otitis, myringoplasty
Microtia
small ear
Atresia
no ear canal
Anotia
no outer ear
External Otitis
fungal (ear wax), makes ear itchy, can cause conductive hearing loss
Myringoplasty
perforations in TM
Middle Ear Pathologies
otitis media, otosclerosis, cholesteatoma
Otitis Media
liquid in middle ear space
acute: 7-10 days
chronic: 10+ days
Otitis Media: treatments
medical: antibiotics
surgical: grommet to allow drainage of liquids
Otosclerosis
bone growth/hardening in middle ear
Carhart's notch--> drop in B/C of 20-30 dB (esp. at 2000 Hz)
Stapedial Otoscleroris
stapes footplate is affixed in oval window
stapedectomy: removal and replacement w/ prosethetic
Cholesteatoma
skin cyst in middle ear or scarred drum, benign tumor in ME airspace
Prenatal Inner Ear Pathologies
congenital, hereditary
from materal infections (rubella, HIV, drugs, CMV)
Perinatal Inner Ear Pathologies
8 weeks before-4 weeks after birth
anoxia: deprivation from oxygen
trauma: forceps delivery
Postnatal Inner Ear Pathologies
meningitis, mumps, measles, rubella, chicken pox, syphilis, ototoxic drugs
Noise Induced Hearing Loss
4K notch, can be unilateral
Menieres Disease
rising slope
sensorineural
vertigo
tinnitus
can be caused by too much aspirin
Presbycusis
hearing loss of old age
high frequencies worse than low
always bilateral, gradual, painless
Acoustic Tumor
benign tumor on 8th CN
trouble with balance
hearing normal if tumor removed
Head Trauma
can damage cochlea and nerve
sensorineural hearing loss of tinnitus
Nonorganic Hearing Loss
fake loss for financial gain
STORCH complex
sensorineural loss that is progressive
Syphylis, Toxoplasmosis, Other, Rubella, CMV, Herpes
Localization of Speech Language Processors
Broca: L hemisphere and aphasia
Dax: same as Broca
Jackson: 96% people have language in L hemisphere
Wada Test: sodium amytal injected into carotid artery in epileptics
Penfield and Roberts: central cortical mapping, Ideational Speech Center
Gershwind and
Cochlear Nucleus
each 8th CN splits into 2 parts: Dorsal and Ventral, then Ventral splits into Anterior and Posterior portions
each nerve fiber sends endings to 400 cells, each cell receives endings from 400 fibers
Cochlear Implant
stimulates 8th CN directly, bypasses cochlea
children benefit (still in critical period)
in US, have to be year old (says Honor), but some earlier
electrode implanted in cochlea, microphone on outside which transmits inside (turns acoustic input to electr
ABI (Auditory Brainstem Implant)
for those with profound hearing loss but can't get cochlear implant because too small or too damaged
stimulate cochlear nucleus in brain stem
standard for patients w/ Neurofibromatosis
Neurofibromatosis
benign tumors on vestibular part of CN 8
Shwanoma on vestibular nerves impinge on auditory portion of 8th CN--> impairs hearing
surgery to remove can damage CN 8 and hearing
ABI--> increased sound awareness
Auditory Neuropathy
Honor calls fake, Joann doesn't
outer hair cells present and functional, but sound info not transmitted to auditory nerve and brain properly
deeper problem w/ PNS, problem w/ connection between cochlea and auditory nerve/ brain
NORMAL OAE, ABNORM/ABSENT A
Damage Risk Criteria
1971: adopted by OSHA-minimize occupational deafness in noisy industrial environments (noise should never exceed 140 dB)
1974: graded types of hearing protection to be worn by workers in areas where sound level exceeds 86 dB for any period of time
TTS
temporary threshold shift, hearing returns to normal next day
PTS
permanent threshold shift, hearing loss lasts forever
Tests for Auditory Processing Disorders
kids have normal hearing, but don't process information normally
don't recognize subtle differences in sounds between words
not result of higher order/more global deficit (autism, etc.)
ABR (auditory brainstem response): overall
hearing (screening) test for cochlea and brain pathways
electrodes on head measure brain wave activity responding to sound
5 waves of response in 10 ms
intensity amplitude smaller=latency longer
OAE (otoacoustic emissions): overall
tests cochlea, not farther in (8th CN)
can detect blockage in outer ear, middle ear fluid, and damage to outer hair cells in cochlea
OAE=sounds given off by inner ear when cochlea stimulated by sound
AIT (auditory integration training)
purpose: straighten out audiogram
used for: autism, tinnitus, accents, depression, etc.
headphones play modulated music at 110 dB (TOO LOUD)
bad stuff: banned in US, no evidence supporting it, expensive
device: EERS (ear education and retraining system)
ABR: stimulus
click
ABR: response
population response (from many auditory nerves)
5 waves of compound action potentials
intensity amplitude smaller=latency longer