MANUAL PHYSIOLOGY PRACTICAL - Repository:The Medical ...
MANUAL PHYSIOLOGY PRACTICAL - Repository:The Medical ...
MANUAL PHYSIOLOGY PRACTICAL - Repository:The Medical ...
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FM/UOJ<br />
Audiometry<br />
Audiometer is an instrument which has several facilities for objective assessment<br />
of hearing ability. It has two types of graded out-puts. One out-put goes to earphones for<br />
testing air conduction. <strong>The</strong> other output goes to a vibrator which can be fitted over the<br />
mastoid process for assessment of bone conduction. <strong>The</strong> instrument can generate pure<br />
tones at selected frequencies which covers the hearing range. Complicated inputs from<br />
tape recorders or conversation are also possible: this facility is not used for routine<br />
testing.<br />
Method:<br />
Seat the subject comfortably and switch on the audiometer. Turn the amplitude<br />
knob to the maximum. Initiate the sounds of pure tones and let the subject to familiarize<br />
with sounds of various frequencies. <strong>The</strong>n explain to the subject that during testing, the<br />
subject will have to indicate as the sound is recognized through the hearing aid.<br />
Reduce the amplitude to the lowest level and fit the earphones. Select the output<br />
to one ear and select the lowest frequency. Switch on the sound generating mechanism<br />
and go on increasing the amplitude slowly. As the subject signals of hearing the sound,<br />
note the amplitude and enter it on the record sheet against that frequency. Repeat the<br />
procedure with the next frequency until all are tested.<br />
<strong>The</strong>n perform the test for the other ear and follow it with test for bone conduction<br />
on both sides. At the end a record of minimum amplitude of the sound heard by the<br />
subject at each frequency by each ear through air and bone conduction is made out.<br />
Exercise: Describe the findings in possible lesions:<br />
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Neurology<br />
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