Welch Allyn AM 232, Руководство по эксплуатации

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12-16-08
Determining the threshold (Pure Tone)
1. The level of the first presentation shall be 10 dB below the level at which the
subject responded during the familiarization procedure. Present the tone for a
period of one or two seconds. Time between tones can be varied, but not shorter
than the duration of the test tone itself. After each failure to respond to a signal,
the level is increased by 5 dB until the first response occurs. After the response,
the intensity is decreased 10 dB and another ascending series is begun.
Note: Down 10 dB, Up 5 dB
2. The threshold is considered to be the minimum dial setting at which a response
has occurred two out of three times. Record this setting on the audiogram form.
Testing procedure
1. Repeat the Familarization and Determining the threshold (Pure Tone) proce-
dures for each tone-setting in the following order: 1000, 2000, 3000, 4000, 6000,
and 8000 Hz.
2. Retest 1000 followed by 500 and 250.
If there is a difference of 20 dB or more between two successive octaves, test the
inter-octave responses (i.e., 750, 1500, 3000 Hz). Record this information on the
audiogram form.
3. Repeat Familarization, Determining the threshold (Pure Tone) and Testing
procedure for the other ear.