CSD 230 Exam 3 PSU Leslie Purcell

normal or sensorineural hearing loss

hearing thresholds are the same for air and bone conduction

conductive hearing loss

thresholds of bone conduction are within normal limits and air conduction thresholds she=ow hearing loss

mixed hearing loss

hearing thresholds show loss by BOTH air conduction and bone conduction. Bone conduction is better than air conduction

Conductive or Mixed

in both, the hearing threshold is better in Bone conduction than air conduction

Air bone gap

15dB at two or more frequencies is a significant gap. it shows need for medical attention (even if hearing thresholds are in normal range)

Why do we use Masking

to eliminate noise from the nontest ear from interfering with the measuring of hearing threshold in the test ear (used for BC and AC)

How do we use masking

usually use a normal band because it is more comfortable for the patient.

broad band "white noise" is loud and uncomfortable

Hearing thresholds

pure tone threshold

speech reception threshold

Pure tone threshold

lowest threshold where people RESPOND 50% of the time

Speech reception threshold

lowest threshold where people are able to repeat word 50% of the time

use spondaic words

Standard starting level for hearing thresholds

30dB

Standard procedure for hearing thresholds

down 10, up 5

Testing in AC and BC

AC-headphones and inserted headphones

BC-Ossilator

Word recognition lists

phonetically balanced and closed set

Phonetically balanced lists

phonetic composition is equivilent to everyday english

closed set lists

phonetically balanced choices with vary by ONE speech sound (rain-pain)

spondaic

2 syllable words

Standard automatic test battery

measurment of auditory function

pure tone air and bone conduction testing

Speech audiometry

SRT and Word recognition

Tympanomotery

impedance testing (what is opposing the flow)

Tympanometer components

pure tone generator (loud speaker)

air pump

monometer

measuring device (microphone)

Pure tone generator

(loud speaker) pure tone is introduced into the ear canal

Air pump

changes pressure in ear canal

Monometer

measure the pressure changes

measuring device

(microphone) measures amount of sound reflected back from the tympanic membrane in response to the air pressure changes

Tympanogram

-measures mobility of TM and air pressure in middle of the ear from +200daPa to -400daPa

Tympanograms that peak at greater than or equal to -150suggest....

malfunction of the middle ear pressure equalizing system (eustachain tube)

OAE

most common clinical application of newborn hearing testing

-NOT a test for hearing threshold. It measures function of outer hair cells

ABR

-most definite test to evaluate retrochoclear function

-screen newborn hearing AND estimate hearing thresholds to those difficult to test

-detect neurological problems

audioneuropathy

dead nerve/doesnt respond properly

clinical uses of ABR

estimate auditory sensitivity

newborn screening

neuro diagnosis

introspective monitoring

**always look for the 5th wave for stimulation

normal hearing threshold

0-15dB

no difficulty with faint speech

slight hearing loss threshold

16-25dB

mild hearing loss threshold

26-40dB

difficulty with only faint speech

moderate hearing loss threshold

41-55dB

frequency difficulty with normal speech

moderatley severe hearing loss threshold

56-70dB

frequency difficulty with loud speech

severe hearing loss threshold

71-90dB

can only understand shouted or amplified speech

profound hearling loss threshold

90+

can not even hear amplified speech

Tympanogram type A

Normal (peak at 0)

=could have sensorineural loss

Tympanogram type B

Flat (no peak)

=fluid build up that causes minimal/ no movement

Tympanogram Type C

Negative (peak below 0)

=eustachian tube dysfunction or otitis media

Tympanogram Type Ad

Deep

=ossicular discontinutiy

Tympanogram type As

Shallow

=tympansclerosis or scarring of the ear drum

Pure tone audiometry

The measurement of hearing thresholds for pure tones of various frequencies using standardized equipment and procedures

acoustic immittence residence

Clinical measurement of the impedance or admittance of the flow of sound energy through the middle ear. Typically includes measurement of a tympanogram and acoustic reflex thresholds

Audiometer Knob

intensity (loudness in dB HL)

Audiometer frequency

octave intervals

125Hz to -8000hz

some to 10k and 12k

Audiometer "interupt switch"

present tone or 'lock' it into speech

Audiometer hearing level dial

range of 10dB to 120dB (5dB or 2dB steps)

Channel of audiometer

usually 2

which ear should you test first

the better ear

which is better, pulsed tone or pure tone?

pulsed tone because it is easier to pick up the break in sound

audiogram x axis

frequency

audiogram y axis

hearing loss in dB

speech banana

where most speech is heard---30 to 50dB

calculating pure tone average

add hearing level at 500, 1000, 2000 Hz and divide by 3

interaurla attenuation

loss of intensity of sound introduced by one ear and heard by the other

(AC is 40-70dB)

(BC is 0dB)

carrier phrase

"say the word"

Purpose of immitance measures

1. identify fluid or pressure in middle ear

2. evaluate eustachian tube function and facial nerve function

3. predict audiometric findings

4. determine hearing loss

5. assist in diagnosing the site of lesion-especially in kids

acoustic immitance measures

tympanometry (most common)

static acoustic immitance

threshold of acoustic reflex

static acoustic immitance

measures ease of flow

expressed in "equivilent volume" in cubic centimeters

equivilent canal volume

volume of ear canal from probe tip to TM

acoustic reflex threshold

lowest possible intensity needed to elicit a contraction of the muscles in the middle ear. This most often occurs between 65-95 dB HL (average response is above 85 dB HL).

The acoustic reflex is a consensual phenomenon; acoustic stimulation to one ear will elicit a muscle contraction and subsequent impedance change in both ears.

Ipsilateral reflex

Sound is put into the ear that the reflexes are being measured in. Stronger than the contralateral ear

Contralateral reflex

sound is put into the test ear and the reflex is measured from the other non-test ear.

tympanometry may have limited value with...

children younger than 7 months

use higher freq for kids because ear canal is smaller and thinner

2 Classes of OAEs

Spontaneous- produced without a stimulus (50% of people, more females than males)

Evoked - produced by a stimulus

stimulus evoked OAE

most difficult to measure and little research

same frequency as pure tone, lower intensity

transient evoked OAE

first measured

clicking stimulus

max displacement of basilar region

amplitude measure over time

*high frequencies to see if hair cells respond

clinical application of TEOAE (transient evoked)

determine injury/damage of Outer hair cells

echo will be missing

path of sound

coclea-cochlea nucleus on same side---both superior olives-contralateral inferior colliculus-contralateral medial geniculate body

high frequencies at the..

base

low frequencies at the...

apex

Distortion evoked OAE

widley used

look at function of outer hair cells/cochlea

pure tones: F2 is higher than F1

most prominent is 2F1-F2

DP gram is measured in...

dBSPL (audiograms are measured in dBHL)

where do electrodes get the best response

the mastoid

where are ABR (electrical potential) responses recorded?

from surface of the head and them amplified

Auditory Brainstem Response (simpler version)

response from auditiry pathway as suditory signal goes through nervouse system (electrical potential)