audio exam 3 Flashcards
pinna malformations
Atresia-no canal Microtia- small Macrotia-big Anotia- no ear Collapsing Ear Canals
process of OM
ET dys-> negative pressure-> vacuum O2 absorbed->fluid pulled out of ME->positive pressure->bulge->perforation->drainage->heal->repeat?
otosclerosis
inflammatory tissue reaction- active otospongiosis or inactive sclerosis
dx- progressive unilateral Cond HL- not visible on otoscope or tympanometry- must look for Carhart’s notch (peak @2k) in audiogram
prevalence: caucasians, delayed onset, females, hormonal changes
tx-Chemical (early- NSAID, Steroids); Surgical (Fenestration- separate stapes from cochlea; Stapedectomy-Remove stapes/footplate, insert prosthesis, restores in 80-95% )
SNHL
usually bilateral (uni= noise damage, tumor), congenital or delayed, with or without comorbid conditions, dominant recessive OR sexlinked
presbycusis
“age related” hearing loss
Occurs in 5-20% at least 65 years old
Occurs in 60% over 65 years old
Audiometric Findings: male>female, Characteristically sloping/sometimes flat
meniere’s disease
Endolymphatic hydrops: Excess pressure in endolymphatic system due to Increased production/reduced absorb of fluid
Classic symptoms: Fluctuating LoFreq SN loss, Usually unilateral, Subjective vertigo, Tinnitus – roaring (like ocean), Fullness in the ear
Medical : Sedatives, Vasodilators, Allergy management, Low salt diet and diuretic- flush out
Surgical-Shunt; selectively section of vestibular part VIIIth nerve, no longer bilateral vestib info going to brain=DIZZY; Labyrinthectomy- may also affect cochlea
ototoxic
Antibiotics, Aminoglycosides “Mycin“- huge quantities (IV), Quinine, Diuretics, Aspirin, Sedatives and tranquilizers, Cisplatin and its derivatives used in cancer tx
Symptoms: Tinnitus, Hearing loss (high freq), Vertigo
Treatment: Withdrawal of drug, Renal dialysis, Variation of drug dosage - monitoring of levels, Audiologic monitoring, Non-Ototoxic Drugs
Noise Induced HL
Acoustic Trauma: Single exposure to high-intensity impact noise
NIHL: Temporary (need rest!) or permanent,Tinnitus, noise Notch at 4 kHz and 6 kHz, Progresses to affect adjacent frequencies
tympanometry
Evaluates the physical properties of the ear, Part of the audiological test battery but not a direct measure of hearing, Rules in/out middle ear pathologies which may contribute to a hearing loss.
Pressure: daPa- Referenced to normal atmospheric pressure; Provides information regarding the functioning of the Eustachian tube: Normal ranges from +50 to -100 (with up to -200 in the borderline range)
Compliance: Cc/cm3 or ml, Measurement of mobility, Provides information regarding ossicular chain, tympanic membrane health, middle ear pathology, Normal ranges .25 to 1.05 for children and .3 to 1.7 for adults
Ear Canal Volume (ECV): ML, A measurement of the physical volume of the ear canal, Estimate of the volume between the probe tip and the tympanic membrane, Provides information regarding outer ear pathology, tympanic membrane perforation, pressure equalization tube patency, Normal ranges from .3 ml to 1.0 ml in children and .65 ml to 1.75 ml in adults
tympanometry results
type A: normal, WNL or SNHL type As (shallow): WNL pressure peak, shallow degree of compliance= limited mobility of the TM; etiologies: Otosclerosis, scarring, or plaque on the TM- heavier type Ad (deep): WNL pressure peak, and deep degree of compliance= excessive movement (hypermobility) of the TM; Possible etiologies: Disarticulation of the ossicles, previously-burst thin or monomeric TM Type B (big ECV): no TM movement can be detected, No middle ear pressure reading, Abnormally low compliance, abnormal ECV; Conductive or mixed hearing loss; Recommend medical referral; etio- small ECV=Wax, normal ECV=Fluid, higher ECV= Perforation or PET Type C: Pressure peak outside the normal range, significant negative middle ear pressure; etio: Allergies, Blocked ET, Developing or resolving of ear infection; May or may not cause Conductive hearing loss
otoacoustic emissions
soft sounds generated by movement of the structures (outer hair cells) in the BM of cochlea
Indirect measure of hearing, brief (transient) stimulation to the cochlea, Rules out a significantly handicapping hearing loss (moderate or worse)
Stimulus via the middle ear, emission occurs within the cochlea, sound echoes back through the middle, external ear, recorded by the mic of device
OAE present: good OHC function, good mid ear transmission (stimulus and response are attenuated and lost in cond. HL ), PTA probably better (lower) than 30dB (ish)
OAE absent: PTA probably worse (higher) than 30 dB, could be any degree (mild to profound)
OAE is a function detector, not a measure
electrophysiologic tests: ABR
Neural response (8th nerve and above) to an electronic stimulation, Responses through electrodes; Can be used in screening or diagnostic testing; Indirect measure of hearing sensitivity= useful in evaluating difficult to test patients (Babies, malingering adults) Click Stimulus- broad frequency, Screening OR Diagnostic, Quickly produces electrophysiological wave forms ( evoked auditory potentials (peaks at CN 8 (I & II), Cochlear Nucleus (III), Superior Olivary Compley (IV), Lateral lemniscus (V)->threshold
electrophysiologic tests: aud steady state response
Frequency specific
Diagnostic only
Complete evaluation takes longer as each frequency is tested
Can approximate configuration of hearing loss
Differentiates between severe and profound loss
aud evoked potentials
Possible to construct an “audiogram” based on ABR results obtained with 500Hz, 1000 Hz, 2000 Hz tone bursts ASSR
Used to identify auditory dys-synchrony (auditory neuropathy), a dysfunction of neural pathways
