Audiological Concepts

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


small ear


no ear canal


no outer ear

External Otitis

fungal (ear wax), makes ear itchy, can cause conductive hearing loss


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


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


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
can be caused by too much aspirin


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


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

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


temporary threshold shift, hearing returns to normal next day


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


ABR: response

population response (from many auditory nerves)
5 waves of compound action potentials
intensity amplitude smaller=latency longer