compares hearing of patient and examiner

normal: bothh stop at same time

diminished: pt. stops hearing before examiner ( pt has problem in sensory/neural

prolonged: pt hears longer than examiner ( pt has problem in conductive

compares bone and air conduction

strike tuning fork place on mastoid, move around pinna. ask pt. to compare loudness of bone and air

Positive rinne: louder by air conduction (normal or sensory/neural

Negative Rinne: louder by bone conduction (conductive)

False-Negative: louder by bone (opposite ear responds by bone leading to comparison of different ears and wrong diagnosis

compares occluded with unoccluded bone conduction

should be louder when occluded 

positive bing: pt hears tone becoming louder and softer (normal or sensory/neural

Negative bing: pt does not hear change (conductive problem)

tests for lateralization of bone conduction

one ear is better than the other

if tone is heard in better ear, problem with sensory/neural

if tone is heard in poorer ear problem is conductive (usually middle ear)

perceives ans pitch (Hz) rate of oscillation of wave.

cycles per second

sound that contains one pitch

movement of air particles back and forth, creates sinusoidal wave.

effects of energy

two types

kinetic (energy due to movement)

and potential (energy that is stored)

no outside force added to sustain movement

-will be damped over time

external forces added to sustain movement

-when force is removed, become free vibration

speed of a sound wave travelling from one point to another; related to medium (eg. solid, liquid, gas)

effected by temerature, altitude and humidity

SPEED OF SOUND: 344 m/s (in air, 20 degrees at sea level)

wave length: velocity divided by frequency

(lower frequency as longer wavelength) 

a given point on the cycle

0 degrees us usually the starting point and considered the standard

out of phase: identical but opposite, cancel each other out

most sounds are more complex than pure tones

 periodic: repeat over time (cycle: vowels)

aperiodic: do not repeat (fricatives)

higher components of complex sound.

(properties of vocal tract, resonant frequency)

occur when complex sound is two tones similar to each other

eg. 500 nd 502 Hz: complex sound

will be perceived as an increase and decrease in loudness every two seconds

(pa) amount of force distribution over an area 

smallest pressure variation required to produce an audible sound: 20 micro pascals

describes the relationship between distance and energy

intensity of a sound decreases proportionally to the square of distance travelled 

most common, sound pressure level

used for most applicaations involveing measurement of sound

ability to tell where a sound originated

interaction between both ears

relative time and intensity between ears

:helps with balance

when two sounds are heard at same time, one sound may cover up the other

occurs during hearing tests to isolate the ears for testing (during bone conduction)

opposition to flow of energy

simple resistance- not influenced by frequency of vibration

:complex resistance -mass reactance, as mass or frequency increases, mass reactance increases

-stiffness reactance, as stiffness increases stiffness reactance increases

-as frequency increases, stiffness reactance decreases.

sever hearing loss!

definite hearing aid and communication training

profound hearing loss!!!

consider cochlear implant, definite communication training.

use degree based on PTA

configuration: eg rising, falling, flat, high frequency hearing loss and trough (happens early in life:very rare)

type of hearing loss: sensory/neural, conductive, erroneous and mixed

goal: determine pt. sensory/neural sensitivity to determine site of lesion.

hearing by bone conduction involves 3 phenomena: distortional bone conduction, inertial bone conduction, osseotympanic bone conduction.

low frequencies: the skull vibrates as rigid mass

Mid frequencies: the forehead and back of head vibrate in opposite phase

high frequencies: the skull vibrates segmentally

inertial response of the ossicles and the inner ear fluid

(lower frequencies; rigid mass) middle ear

distortional response of the inner ear space

(higher frequencies; segmentally) inner ear

osseotympanic response rediated into the external ear canal

(all frequencies) outer and middle ear

normal hearing: both within normal limits, no gap

Sensory/neural: both impaired, no gap

Conductive: BC within normal limits, AC not; ABgap

mixed: both impaired, AC worse; gap

Must be 10 dB or more to be a gap

Speech detection Threshold (SDT): lowest level at which a speech signal is detected as being present

Speech Recognition Threshold (SRT): (prefered) lowest level at which speech signal is recognized/understood, obtained with sporadic words, 50% considered the threshold

SRT should be higher than SDT (should be around 12 dB difference; wont get this with erroneous)

SRT should be the same as PTA (within 6 dB of each other, no more than 10 dB)

most comfortable loudness

people with normal hearing find speech most comfortable: 40-55 dB

relative to SRT

uncomfortable loudness, people with normal hearing find speech becomes uncomfortable at the audiometer limits (110 dB)

people with some hearing disorders find speech becomes uncomfortable at much lower levels (inner hearing loss)

estimation of a person's performance on supra-threshold speech tests based on amount of speech signal available

count the number of dots below the hearing threshold

value in % of conversational speech audible to listener at 3-6 feets from source.

as AI decreases, hearing handicap increases.

guide identification of abnormalities in auditory system.

immittance: all encompassing term for measures made of the tympanic membrane (TM) impedance, compliance or admittance.

measurements; static acoustic compliance/admittance: mobility of the TM in response to air pressure in external ear canal

tympanomatry: middle ear pressure, determined by mobility of TM as pressure is changed in ear canal

Acoustic reflex; cotraction of middle ear muscles in response to loud sounds

impedance is determined by: resistance, mass, stiffness

mass and stiffness make up complex resistance (reactance) mass and stiddnesss reactance related to each other and dependant on frequency

resistance; determined by ligaments in middle ear

mass; determined by the weight of bones in middle ear

stiddness; determined by fluid pressure from middle ear

ear canal should be free from debris and wax, must obtain air-tight seal of ear tip in ear canal.

increase pressure with pump to +200 daPa (observe pump to ensure seal)

determine equivelent volume in cc?

gradually decrease pressure to maximum compliance (pressure on both sides of TM is equal)

compliance of the middle ear is difference

most equipment provide data on printout

:compliance/admittance values below normative range indicate less than normal mobility of TM, may result from fluid in ME, lack of mobility of ME bones or TM

: compliance/admittance values above normative range indicate more than normal mobility of TM, may result from interruption of ME bones, too mobile TM

TM vibrates best when pressure on both sides is equal

purpose is to determine point of magnitude of greatest compliance.

indicates normal ME pressure, but shallow compliance

two muscles: tensor tympani and stapeduis

muscles contract in response to loud sounds

causing TM to stiffen.

usually happens at 85-100 dB SPL

stimulus is typically a puretone (500-4000 Hz)

measure compliance/admittancee as ME stiffens

Probe ear: ear in which the sound is presented.

acoustic reflex is named for the stimulus ear.

ISPILATERAL: measured nd presented in the same ear.

CONTRALATERAL: measured (compliance) and presented (reflex) to opposite ear

stimulus RIGHT 

probe RIGHT

probe LEFT

stimulus LEFT

stimulus RIGHT

probe LEFT

stimulus LEFT 

probe RIGHT

begin testing at low stimulus levels (70 dB)

raise stimulus in 10 dB steps

when change in compliance is observed, decrease in 10 dB steps and raise in 5 dB steps

Acoustic reflex threshold (ART) is lowest level at which reflex is seen (ie. change in compliance)

must be able to measure change in compliance

type B tympanograms prevent measurement of ART

(cant measure reflex)

reflex activating signal must be able to reach inner ear conductive components may prevent elicitation of ART

(prevents ellicitation of Reflex) 

reflex is absent at limit of equipment

PT- RE: WNL, LE:CHL

ART- Right: contra; ABSENT, ipsi; WNL

Left: contra; ELEVATED, ipsi; ABSENT

Right contra absent because of probe ear principle (probe in left ear)

Left Contra elevated by amount of CHL (stimulus ear principle; depending on level of HL)

Left ipsi absent because of probe ear principle

Puretone results: RE: WNL, LE: SNHL (cochlea) mild/moderate

ART- Right contra; WNL ipsi; WNL

Left contra; ABSENT ipsi; ABSENT

Right contra and Right ipse WNL because stimulus to right ear is WNL

left contra and ipsi absent becasue stimulus to Left ear (has cochlea pathology) cannot elicit response to equipment

Pure-tone Results: RE: WNL, LE: SNHL (cochlea) severe/profound

ART- right: contra; WNL, ipsi; WNL

LEft: contra; ABSENT, ipsi; ABSENT

Right contra and ipsi WNL because stimulus is in Right ear (WNL)

left contra and isi absent because stimulus to left ear has cochlea pathology

pure tone: RE-WNL, LE-SNHL

ART: right contra-WNL, ipsi- WNL

Left contra-ABSENT/ELEVATED, ipsi-ABSENT/ELEVATED

right contra and ipsi WNL because stimulus to right ear is

WNL

Left contra and ipsi elevated or absent because stimulus to left ear (cannot complete pathway to stepedius muscle)

pure-tone: RE-WNL, LE- WNL (CN 7 lesion)

ART: rightcontra- ABSENT, ipsi- WNL

LEFT contra-WNL, ipsi-ABSENT

Right contra and Left ipsi are absent because thy are both measured at left middle ear- which is not being innervated by CN 7

left contra and Right ipsi are WNL because they are both measured at right middle ear where there is no pthology

Pure tone: RE- WNL, LE- brainstem:could be anything.

ART: Right contra- ABsent, ipsi- WNL

left contra- Absent, ipsi- WNL

both contra reflexes are absent because a portion of the brainstem where the pathway crosses over is damaged

both ipsilateral reflexes are WNL because there is no hearing loss and no damage to ipsi pathway

puretone: RE- WNL, LE- WNL (cortical lesion, speech results could be funky)

ART: right contra- WNL, ipsi- WNL

left contra- WNL, ipsi-WNL

all reflexes are WNL because the lesion is abouve the reflex pathway, in auditory cortex

sound produced by cochlea without any external stimulation

occur in over 1/2 the population of people with normal hearing loss

not clinically used

sound produced by cochlea in response to external stimulation

used clinically to differentiated sensory from neural hearing loss

used to identify hearing loss in infants

in order to observe OAE, need the middle ear to be intact

signal needs to travel to cochlea through ME

emission needs to be travelling back to probe through ME

con provide frequency-specific information

because activitating specific regions of cochlea

present OAE indicate no worse than mild HL

absent OAE confirm cochlea pathology

does not rule out possibility of also having a retrocochlea pathology

measurement of electrical responses generated within cochlea and above

used as objective measures of integrity of auditory system

need a sophisticated signal-averaging system to remove ongoing electrical noise

measure signal as it moves along auditory pathway

amplitude-strength/magnitude of AEP

Latency-time between presentation of stimulus

measurement of electrical responses from cochlea

electrode placed near cochlea (in ear canal, or surgically placed closer)

used to monitor cochlea during some surgical procedures, enhance results of other AEP tests, monitor inner ear pathology.

latency: 0-10 ms

electrodes placed on scalp

can use tone bursts or clicks to elicit

a wave from with distinct waves apears

waves 1 &2: CN 8

wave 3: superiour olivary complex

wave 4: pons,lateral lemniscus

wave 5:midbrain,lateral lemniscus inferiour colliculus (most prominent)

waves 6&7: undetermined

can be used to estimate auditory thresholds

threshold estimated at lowest intensity wave 5 can be seen

usually within 10-20 dB of behaviour results (when using a tone burst)

can be used as a neurological screening

present at a high click rate to compare to regular click rate (tells it to fire rapidly)

ABR is abnormal if: intervals are prolonged 

wave latency is different between ears

amplitude ratios are abnormal (between wave 5 and 1)

wave 5 is abnormally prolonged or disappears with high click rates

estimating hearing thresholds from ABR can be time-consuming

ASSR helps reduce the time needed to astimate thresholds

ASSR has added advantage of not being affected by persons' sate of consciousness

ABR and ASSR are complimentary techniques

(latency: 15-60 ms)

reflects activity from cortex

equipment and set up similar to ABR

unlike ABR, need to keep quiet and alert

can estimate thresholds with AMLR

can assess neurological function of higher cnetral auditory nervous system

latency: >60 ms

can us pure tones to elicit response

responses are very affected by pt's attention

Post 300ms response may be related to perception (ie processing) rather than simple electrical response

MMN (mismatch negativity) may be useful in rehabilitation (eg. discrimination of sounds)

:not used much clinically

lowest level at which children respond to stimulus

:may be well above their actual threshold level

pair reinforcer with sound, then delay reinforcer until child responds to sound source

conditioned orientation reflex (COR): from 4 months, used in sound field

visual reinforcement audiometry (VRA): from 6 months, can be used with headphones

tangible reinforement audiometry (TROCA): from 18 months, reinforcer is something tangible(eg. food)

PLay audiometry: from 4 years, reinforcer is praise, not game

difficulty using auditory information that cannot be explained by the audiogram, or other factors (eg. ADHD)

-poor listening skills, difficulties in reading and spelling, difficulty understanding speech in noise.

occurs in 2% of population and is more common in boys'

intervention includes increasing SNR, metalinguistic training, metacognitive training.

typically have mild/moderate SNHL

abnormal/absent ABR

absent/ elevated ART

normal OAE-site of lesion is beyond level of cochlea

hearing aids and mixed results

cochlea implants may be successful

may communicate via signed language

children are known to falsely show hearing loss or to exaggerate hearing losss

 typically have little or no difficulty communicating

speech thresholds disagree with pure tones

often related to acedemic, emotional, or socail difficulties

main job: funnel sound and sends to external auditory canal

made up of cartilage

unusually small pinna, often the opening os obstructed

causes hearing loss

closure of the opening to EAC

:often occurs with other conditions, such as treacher collins, and charge syndrome

narrowing of the canal

can be narrowed by infection or inflamation

infection or inflammation in EAC

often seen in swimmers who get water trapped in EAC

may be caused by allergic reactions

cannot test hearing!

systematic antibiotics and eardrops not usually helpful

more often irrigation or a wick with antibiotics is used

some forms need to be aggressively treated to prevent necrosis (tissue dying-oh no!) and spread of infection

when cerumen is pushed into bony portion, has no way to migrate, must be removed.

may lead to hearing loss ranging from mild ro moderate

can result from pressure in ME, chronic ME infection, trauma (physical and acoustic)

perforations from trauma tend to heal better than those from chronic conditions

myringoplasty has been shown to help restore hearing

tymposclerosis can result from repeated perforations and infection

fallopian canal- contains portion of facial nerve..

facial nerve: CN 7 runs along side auditory nerve (CN8)

chorda tympani-branch of facial nerve: carries information about taste.

stapedius muscle: attaches to stapedius, tenses OW and decreases amplitude of vibration (main acoustic reflex muscle)

Tensor tympani: attached to malleus, tenses TM

both respond reflexively and bilaterally

many ME pathologies arise from eustatian tube dysfunction (ETD)

swelling of ET caused by allergies, infection, inflamed adenoids

structuraly abnormalities of ET also cause ETD

if ET cannot open, cannot equilize ME pressure.

TM becomes retracted

fluid builds up in ME, may become infected

valsalva and toynbee maneuvers can help

infection of ME (OM) is seen in 70% of children before the age of 2.

factors: ethnicity, age, SES, ETD, barotrauma (quick change in pressure), compromised immune system, exposure to cigarette smoke.

organisms reach ME viaET, often by blowing the nose.

supprative OM often creates ME pain, may be chronic (COM) or acute (AOM)

organge colour, retracted TM

amount of CHL depends on amount and type of fluid in ME space, shape of audiogram is usually flat

word recognition scores are usually excellent

Type B tympanogram (flat)

ART is absent due to probe ear and stimulus ear principles

ABR latencies are prolonged

AOE are absent (not measureable)

ETD can cause a vaccum to form in ME drawing fluids into ME space-resulting in serious effusion

more common in babies bacause ET is open and horizontal

similar audiometric findings as SOM except audiogram shape(more loss in high frequencies)

may see affect on BC thresholds

continued pressure may result in spontaneous perforation of TM 

myringotomy followed by insertion of PE tube (grommets) is common treatment 

PE tubes function to equilize the pressure between the EAC and ME

may also help keep ME drained

to test the patency of the tube- conduct immitance test and observe the Vea (should be very large)

thick mucoid secretions accumulate in ME

become think and prevent ME from vibrating

similar audiometric results as SOM

if left untreated, HL may not be reversible by myringtomy

may leave adhesions on occicles

may result in tympanosclerosis

may cause language delay

TM bulges out, cone of light not in the right shape or on the right side, orange TM

can be ery dangerous, very close to cranial cavity

skin in ME space can form a cholestroma

sac with rings of keratin and squamous cells along with cholesterol

perforated TM and history of OM can lead to cholestroma

erroding tissure and even entering cranial cavity

surgery is best know treatment

may cause permanent hearing loss

infection can spread to the mastoid area

can be very dangerous

mastoidectomy is often performed

can create cavity in mastoid

needs to be continually monitored

surgical reconstruction of ME structures

myringoplasty-reconstruction of TM

may include prosthetic devices or bone grafting 

hearing can be improved, but is sometimes worsened

when ossicular chain is interrupted, will see a conductive hearing loss with a type Ad typanogram

having ET that are continually open rather than closed

can result in autophony (hearing yourself loudly)

may interfere with speech production (end up speaking too softly, voice slightly out of sink, start stuttering)

will typically have type A tympanogram

can observe compliance changes via tymapnometry

-if ET is open, will increase during inhalation and decreases during exhalation

hereditary in 70% of cases, common in women, symptoms arise between puberty and 30 years

formation of growth in bone (spongy) around footplate

footplate becomes fixed in OW, resticting movement

my see bluish tint in whites of eyes, and a rosy glow in the TM

may report "paracusis willisii" (hearing better in bckground noise, because in background noise people speak louder and dont hear the background noise)

low frequency airbone gap

fixation causes "carhart notch"

BC thrsholds elevated w/ notch at 2k Hz

due to inertial component of BC

see drop in LF thresholds at first, then moves to HF

tympanogram shows type As- indicating reduced mobility of stapes

ART is absent becasue stapes cannot move

(sight of lesion: stapes) 

OHC's responsible for fine tuning

sharpen travelling wave (decending communication)

damage to OHC results in poor understanding of speech, esp in background noise (because wave is flat and broad)

reduced audibility for soft sounds (upto 40-60dB) because OHC amplify speech

IHC responsible for sending signal to auditory nervous system

otitis media-toxins from bacteria spread to IE

meningitis can result in total loss of hearing

Viral infections (mumps, measles, chickpox) 

labyrinthitis - may affect both hearing and vestibular function (where vestibular an hearing portions connect)

ototoxic drugs: prescription- eg. chemotherapy (tinnitus)

-OTC drugs-eg. aspirin

-recreation drugs- eg. marijuana

tend to have HF loss and tinnitus

vestibulotoxic drugs: many of these drugs also have effects on the vestibular system

breif exposure to loud sounds causes temporary threshold shift (TTS)

prolonged exposure or very loud sounds cause permanent threshold shift (PTS)

typically see noise notch at 4k Hz, tinnitus may also occur

reduce exposure and hearing protection devices (HPD) can reduce risk

most industrial nations have strict regulations from work-place noise

recreational noise not regulated

not always practical: law enforcement, military

required symptoms: sudden attacks of vetigo, hearing loss(often unilateral) and progressive), low frequency tinnitis/aural fullness

probably caused by endolymphatic hydrops: oversecretion or under absorption of endolymph (creating the feeling of fullness)

Symptoms can occur without warning, so effects can be debilitating

hearing loss due to aging

also damages the nervous system

happens in 60s

begins as symmetrical HF loss, then increases and includes more mid and LF

poor understanding of words in quiet and especially in noise is common

1:1 ratio between input and output, gain is constant

provides more overall amplification

>1:1 ratio between input and output

gain varies depending on input level

can have boot with Fm transmitter

have move to 'micro' BTE

fits a wide range of hearing losses, reduced feedback

can create occlusion, visible

custom made for client

should completely fill the cavum concha

fits wide range of hearing losses

small

fill entire concha can create occlusion

has small volume control

vent plugged up because of feed back

smallest, takes advantage of ears resonance

fits small range of hearing loss, can have feed back

can wriggle out

small

takes advantage of ears resonance

fits small HL range needs deep fit

open fit no occlusion

reciever away from microphone so decreased feedback

can be fit for profound loss.

comfortable

VERY POPULAR AT THE MOMENT!