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Test procedure

Several different methods followed.

Most standard: Recommended by Carhart and Jerger (1959) and ASHA (1978)
1.
Start at 1000 Hz, 30 dB HL.
2.
If no response, raise to 50 dB HL, and continue to raise in 10 dB steps till response
is obtained.
3.
When response is elicited, then level lowered in 10 dB steps till no response is
elicited.
4.
Now, increase level in 5 dB steps till response occurs.
5.
Then, lower in 10 dB steps. (Down 10, up 5)
6.
Threshold: Lowest level at which response is given for at least two out of three
presentations (ANSI, 1986).
http://www.parrotsoftware.com/demos/demos.htm
Procedure, cont’d.

Record threshold on audiogram.

Take into account correction factors, if any.

Measure thresholds at all frequencies.

Reliability of thresholds checked using 1000 Hz.

Check poorer/other ear.
Audiogram: Graph of hearing as a function of frequency.
Audiogram data


Identification: Name, date of testing, examiner, equipment
Unmasked AC thresholds (ASHA 1990):



Red  for right ear
Blue X for left ear
Symbols connected with red and blue solid lines.

Pure tone average (PTA): Average threshold levels at 500, 1000,
and 2000 Hz.

Sometimes, two-frequency PTA used: Average of two lowest
thresholds at 500, 1000, and 2000 Hz.
Draw the audiograms for the following sets
of audiometric data
Right ear
Left ear
250
500
1000 2000 4000 8000 250
500
1000 2000 4000 8000
AC
0
5
0
10
10
5
10
10
5
0
BC
0
0
0
5
5
0
5
5
0
0
AC
40
40
35
40
45
35
45
40
40
50
BC
-5*
0
5*
10*
0*
0*
0*
5*
5*
0*
AC
25
30
35
45
50
30
40
45
50
60
BC
25
35
40
45
55
25
35
40
45
55
AC
65
70
70
75
65
70
65
70
70
70
BC
25*
30*
35*
40*
50*
25*
30*
40*
50*
55*
5
40
60
75
5
45
55
75
Interpretation of AC thresholds: Degree of
hearing loss
PTA (dB HL)
Degree of Hearing Loss
-10 to 15
Normal hearing
16 to 25
Slight hearing loss
26 to 40
Mild hearing loss
41 to 55
Moderate hearing loss
56 to 70
Moderately-severe hearing loss
71 to 90
Severe hearing loss
> 91
Profound hearing loss