audiology pretest

when do we use masking?

1. there is greater than 10 dB difference between AC of test ear and BC of non test ear (bc its over attenuation), there is a greater than 40 dB difference between AC results between ears

2. you suspect bilateral conductive or bilateral mixed hearing loss

3. assymetry between AC/BC between ears

what can air conduction audiometry determine?

degree of hearing loss at each frequency, for each ear

what can air conduction audiometry NOT determine?

can’t localize site of damage

3 types of transducers for air conduction

supra aural earphones, insert earphones, speakers

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bone conduction on forehead (unmasked)

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bone conduction, right ear, unmasked

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bone conduction, left ear, unmasked

attenuation for bone vs air

air conduction mechanism

normal means of sound transmission in everyday scenarios

air conduction audiometry

determines the intensity threshold in dB at which a person just begins to hear sound at each frequency tested

perceptual correlates w/ units

loudness for intensity in dB, pitch for frequency in Hz

earphone placement

make sure head band fits head appropriately, center of earphone is seated over ear, use insert earphones when appropriate

type A, normal

type B, middle ear pathology

type C, negative pressure (Eustachian tube dysfunction)

type As, stiff eardrum

type Ad, flaccid eardrum

SRT

speech reception/recognition threshold

WRT

word recognition threshold or score

WDT

word discrimination threshold or score

purpose of speech reception threshold

threshold for reception of speech stimuli, reliability and cross check of pure tone findings

PTA

pure tone average at 500, 1000, 2000 Hz

indication of pseudohypocusis

PTA scores should be similar to speech recognition threshold

why do we use those PTA frequencies?

vowels used for speech power are concentrated at lower frequencies

PTA frequencies

500, 1000, 2000 Hz

how do we test SRT? (3)

spondees and spondee picture boards, cold running speech, point to body parts such as eyes nose

methodology for threshold search (4)

familiarize patient with several words first, patient repeats word or points to picture, Hughson-Westlake down 10 up 5 dB, 2/3 accuracy = threshold

SRT board

what is this an example test of?

speech reception/recognition threshold

headphone colors

right red, left blue

2 similarities between SDT/SAT

still uses speech stimuli, still seeks a threshold in dB

which will always have a LOWER dB HL: SRT or SDT?

SDT by about 7-9 dB lower than SRT

recognition or understanding of the speech stimuli does not occur until…

about 7-9 dB HL above the level of detection

should you start low or high? (intensity)

always start high and work low

slide 15

difference between speech recognition vs word discrimination

WRS is above threshold so should be 100%, SRT should be able to repeat back 50% of time close to pure tone average

2 methods for testing word descrimination ability

30-40 dB SL, most comfortable listening level (preferred)

MCL

most comfortable listening level

benefits of using MCL (4)

inter test reliability, reference for discrimination testing, indicator for narrow dynamic range, future use in hearing aid fitting

ASSR

auditory steady state response

DPOE

distortion product otoacoustic emission, complex stimulation to cochlea

TEOAE

transient evoked OAEs, brief/transient stimulation to the cochlea

which OAEs are more widely used?

distortion product

are OAEs direct measure of hearing?

no