Subjective Hearing Assessment: Pure-Tone and Speech Audiometry Flashcards
Testing on adults and school-aged children
SUBJECTIVE (behavioral) testing
Complete audiometric examination:
Case history
Otoscopy
Pure tone testing air conduction (right/left)
Pure tone testing bone conduction (right/left)
Speech audiometry
Spondee/speech reception THRESHOLD (dB level): SRT
Word recognition score (percentage): WRS (sometimes called “discrim”)
Tympanometry
Acoustic reflexes
Audiometer
Device used to determine hearing thresholds that generates the pure-tone
signals of various frequencies as well as masking noise and speech
Calibrated regularly by a qualified professional to ensure that output is equivalent to a known standard
TWO TYPES OF audiometer
Clinical: used for behavioral audiometric assessment
Screening: used for screening (pure-tone stimuli only)
Two main components of Audiometer
Oscillator: generates pure-tone stimuli
Attenuator: controls intensity of stimuli presented
Oscillator
generates pure-tone stimuli
Attenuator:
controls intensity of stimuli presented
Different stimuli used with audiometer
Pure tones: 125Hz-12kHz (250-8000Hz)
Speech
Different transducers used
with audiometer
Headphone: two types
Supra-aural
Insert
Bone oscillator
Loudspeakers (for soundfield testing)
Sound-Treated Audiometric Booth
Two layers of metal panels for walls, with holes in walls for cables
Thick metal double doors close tightly to prevent sounds from leaking in
Incandescent (rather than fluorescent) lights used to reduce ambient noise level
Ventilation with sound attenuation
Raised floor is carpeted
No windows (except between audiologist and patient)
Case history obtains the following
Pertinent identifying information
Nature of past and present hearing problems
Other medical problems
Prior use of amplification
TAKE THE TIME TO DO YOUR HOMEWORK! It will pay off
For children, additional information includes
Details about mother’s pregnancy and the child’s birth
Development of gross and fine motor skills, development of speech and language
Childhood diseases
Otoscopy
Otoscopy: inspection of the pinna and EAM using an otoscope for the presence of
outer ear malformation/earpits/tags
foreign bodies
occluding cerumen
signs of inflammation/irritation
blood/pus/scarring/dried blood
Appearance of TM also noted
Normal TM is gray/translucent with manubrium visible
ME disease may be suspected if
TM bulging or distended or opaque
Fluid is visible in ME space, or
Scars, perforations, and/or tears are present
Air conducti
Air conduction: threshold obtained using headphones (supra-aural or insert)
Degree of hearing sensitivity determined
Slight, mild, moderate, moderately-severe, severe, profound
Tests outer, middle, and inner ear
Bone conduction:
: threshold obtained with bone oscillator
Type of hearing loss determined
Conductive, sensorineural, mixed
Thresholds reflect function of cochlea/inner ear only (outer- and middle-ear function bypassed)
Air Conduction Assessment
Start at 40 dB HL
Use staircase method (down 10 dB/up 5 dB strategy) to determine threshold
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Frequencies tested with air conduction
Typically, octave frequencies of 250, 500, 1000, 2000, 4000, 8000 Hz assessed
Interoctave frequencies of 750, 1500, 3000, and 6000 may also be assessed
Tested if there is a 15-dB difference between two octave frequencies or if patient is considering amplification
Patient Response
Instructions given to patient when tone is heard
Audiologist should avoid inadvertently giving cues
Raise hand
Press response button
Vocal response (“yes”)
False Responses
False negative: no response when one is required
False positive: response when no stimulus is presented
Bone Conduction Assessment
Signals via bone oscillator (usually placed on the mastoid process of the temporal bone )
The pure tone directly stimulates the cochlea, bypassing the outer ear and middle ear systems
If air conduction shows a reduction in hearing sensitivity but bone conduction shows normal sensitivity, the impairment probably results from an obstruction of the outer or middle ear (conductive hearing loss)
If air- and bone-conduction thresholds are similar, a sensorineural hearing loss is presumed
Normal hearing
Bone and Air conduction are the same
Conductive hearing lost
bone conduction results are
normal and air conduction is bad
sensorineural hearing lost
Air and bone conduction are bad at equal amount
mixed hearing lost
Bone is poor and air is even poorer:
Bone Conduction Assessment Continuation
Start at 40 dB HL
Use staircase strategy (down 10 dB/up 5 dB) (same as air conduction assessment)
Frequencies tested: 500, 1000, 2000, 4000 Hz
Interoctave frequencies tested if assessed during A/C up to 6000 Hz
Recording
< threshold of right ear (unmasked)
> threshold of left ear (unmasked)
[ threshold of right ear (masked)
] threshold of left ear (masked)
Air–Bone Gap
Difference between A/C and B/C thresholds at a given frequency
Air–bone gaps ≥15 dB represent a significant conductive hearing loss in adults
In pediatric clients, more conservative air–bone gap of ≥10 dB HL is used
May require medical referral, even if the A/C thresholds are ≤25 dB HL at all frequencies
When A/C and B/C thresholds are approximately the same at all test frequencies, this suggests a sensorineural loss
Mixed Hearing Loss cont
When both A/C and B/C thresholds are reduced in sensitivity, but B/C testing yields better results than A/C testing
The patient’s hearing loss is partially conductive and partially sensorineural
Masking
The process by which the threshold of a stimulus is elevated by the simultaneous introduction of another sound
Used whenever there is a possibility of cross-hearing, which is the reception of a sound signal during a hearing test (either by A/C or B/C) at the ear opposite the ear under assessment
When masking is used
Air conduction testing
Both pure-tone and speech assessments
Bone conduction measurements
Masking cont
Sound (typically frequency-specific narrowband noise) presented to the non-test ear to prevent it from perceiving the test signal presented to the test ear
Cross hearing:
contralateralization of the test signal (crosses to opposite ear)
Interaural attenuation
Interaural attenuation: the loss of energy of a sound presented either by A/C or B/C as it travels from the test ear to the non-test ear (aka crossover levels)
Air conduction: depends on transducer used
Supra-aural phones = 40 dB HL
Insert phones = 70 dB HL
Bone conduction = 0 dB HL
Rationale for Speech Audiometry
Main goal: to quantify a patient’s ability to understand everyday communication
Why?
We don’t speak in pure tones, nor do we speak at threshold levels
A basic tool in the overall assessment of hearing handicap
Other goals in speech audiometry
Check validity of pure-tone audiometry
Determine reference for suprathreshold testing
Assessment of amplification or rehabilitation
Estimate degree of communicative function
Monitor progress in aural rehabilitation
Calibrated amplifying system
Inputs
microphone, tape recorder, CD player
Calibrated amplifying system
outputs
earphones, bone oscillator, loudspeaker in the test room
Clinical Decisions in Speech Audiometry
Mode of test presentation
Voice (monitored live voice, MLV)
Tape/CD (preferred mode of presentation)
Mode of response
Voice
Written (i.e., forced choice)
Sign language
Listening conditions
Masking
Speech reception threshold
Speech reception threshold (SRT): lowest intensity at which a person can identify simple speech materials approximately 50% of the time
Assessment of Speech Threshold
Speech reception threshold (SRT): lowest intensity at which a person can identify simple speech materials approximately 50% of the time
Obtain threshold for speech in dB HL
Staircase method used (as in AC and BC)
Word lists: spondaic words (spondees)
Spondee: two-syllable words with equal emphasis on each syllable; low-frequency-dominant sounds
Word recognition score (WRS)
Word recognition score (WRS)
Also called speech discrimination score (SDS) or word discrimination score (WDS)
Phonetically balanced (PB) monosyllabic word lists
Assessment of Suprathreshold Speech Recognition
Word recognition score (WRS)
Also called speech discrimination score (SDS) or word discrimination score (WDS)
Phonetically balanced (PB) monosyllabic word lists
Multiple-choice tests (e.g., California Consonant Test)
Sentence tests
Assessment of Suprathreshold Speech Recognition cont
Obtain score in % correct
Either 50 words (full list) or 25 words (half list) used
Method to determine WRS
More often than not, present at 35 dB above SRT
Determine “MCL” most comfortable listening level
Word Recognition Score List
Carrier phrase: “Say the word…” (VU meter)
In order of difficulty
mew, bathe, felt, ache, knees, twins, thing, stove, true, skin
as, she, or, it, jam, me, there, aisle, them, wet, could, toe, not, up, you
Phonemically balanced
Word Recognition Scores cont
88-100%: EXCELLENT
72-84%: GOOD
60-68%: FAIR
Below 60%: POOR
Uncomfortable loudness level (UCL) and most comfortable loudness level (MCL)
Uncomfortable loudness level (UCL) and most comfortable loudness level (MCL)
Both suprathreshold levels are determined in dB HL
Method to determine each level
Dynamic range: the difference between UCL and SRT
Example: UCL = 110 dB HL; SRT = 10 dB HL
Dynamic range in this case equals 100 dB
Speech-in-competition measures
Speech-in-competition measures
Sentence recognition tests
Synthetic Sentence Identification (SSI)
Speech-in-noise (SPIN) test
Staggered Spondaic Word (SSW) test
Ling 6-sound test
/a/, /u/, /i/, /m/, /sh/, /s/
Measured as number correct
Issues in Speech Audiometry
Masking to avoid cross hearing
Recommended whenever speech audiometry is assessed
Testing non-native speakers of English
Numerous word lists available for purchase in Spanish, Portuguese, Italian, French, Tagalog, Polish, Russian (just to name a few languages)
