Topic 4

spectacularscarecrowΤεχνίτη Νοημοσύνη και Ρομποτική

17 Νοε 2013 (πριν από 3 χρόνια και 4 μήνες)

63 εμφανίσεις

TOPIC
4

BEHAVIORAL ASSESSMENT
MEASURES

The Audiometer


Types


Clinical


Screening


The Audiometer


Components


Pure tone oscillator


Attenuator


Interrupter switch


Output transducer

o
Headphones


Supra
-
aural


Insert

o
Bone conduction vibrators


Forehead


Mastoid

o
Loudspeakers


Audiometer Components

Pure Tone Audiometry

“The aim of pure tone audiometry is to
establish hearing threshold sensitivity
across the range of audible frequencies
important for communication”

The Audiogram

Air Conduction vs Bone
Conduction Testing

Air conduction tests
the entire auditory
system. Bone
conduction
bypasses the
conductive
mechanism, so it
tests only the inner
ear.

Audiometric Symbols


Unmasked air conduction


Left ear


Right ear


Unmasked bone conduction


Left side


Right side


Masked air conduction


Left ear


Right ear


Masked bone conduction


Left ear


Right ear


No response

What the Audiogram Says
About the Impairment






Within normal limits

Mild


Moderate

Severe

Profound/deaf

What the Audiogram Says
About the Impairment

The configuration of
the hearing loss



Flat


Rising


Sloping

What the Audiogram Says
About the Impairment


The degree of hearing loss


The configuration of the hearing loss


The type of hearing loss


Conductive


Sensorineural


Mixed


Establishing a Pure Tone
Audiogram

o
Establish which is the better ear and
test first

o
Start air conduction testing at 1000 Hz

o
Begin at 30 dB HL. If there is no
response, increase intensity in 20 dB
steps until you see a response

o
Follow the “down in 10, up in 5” rule

ASHA Procedure

Hypothetical threshold search for a listener whose
threshold is 35 dB HL. A + indicates the listener
heard the presentation, and a
-

shows the listener
didn’t hear the tone. Notice that the hearing level of a
trial is raised by 5 dB following a
-

and is lowered by
10 dB following a +.

Establishing a Pure Tone
Audiogram

o
After several crossings of the same
intensity, pick threshold as an intensity
where 50% of the time the listener responds
correctly

o
Move to 2000 Hz, 3000 Hz, 4000 Hz, and
8000 Hz (as a minimum)

o
Pick up the low frequency (500 and 250 Hz)
tones

o
Repeat for the other ear

Speech Audiometry

Uses:


Sensitivity for speech


Speech awareness threshold


Speech reception threshold


Pure tone cross check


Speech recognition


Differential diagnosis


Central auditory processing


Estimate of communicative function

Speech Audiometry

Materials


Types


Nonsense syllables


Monosyllabic words


Spondaic words


Sentence tests

Speech Audiometry


Relationship of redundancy of informational content and
sensitivity to the effects of hearing loss on three types
of speech recognition materials

Speech Audiometry


Intrinsic redundancy


Extrinsic redundancy


Frequency
--
low pass filtering


Time
--
time compression


Intensity
--
high presentation levels


Competition
--
speech in noise


Binaural
--
dichotic measures


Speech Audiometry

Relationship of intrinsic and extrinsic
redundancy to speech recognition ability in
normal listeners

Speech Audiometry

Clinical Methods


Speech thresholds


Speech Reception threshold

o
Start audible

o
Present four spondees

o
Calculate percent
-
correct response

o
Follow down in 10, up in 5 rule

o
Stop at an intensity that provides 50%

Speech Audiometry

Clinical Methods


Speech thresholds


Speech Reception threshold


Speech Awareness threshold


Word recognition testing

Word Recognition Testing

Things to consider:


Materials


Goals?


Amount of extrinsic redundancy you need?


Language level?


Other special needs or considerations?


Word Recognition Testing

Things to consider:


Materials


Presentation


Monaural?


Binaural?


Headphones?


Sound field?


Word Recognition Testing

Things to consider:


Materials


Presentation


Presentation Level


Maximal ability


Normal conversational level


Speech Audiometry

Interpreting speech discrimination results. Typical
results based on disorder site



Other Behavioral Measures

Uses:


To determine a functional or exaggerated
hearing loss


To provide additional information necessary
to fit amplification


To determine the presence of recruitment and
adaptation


To determine some measure of binaural
integrity