Operation Manual MA 25/MA 25e
MA 27/MA 27e
The device is plugged into a power source.
Intensity displayed on the screen reflects the intensity/volume
presented to patient. To change, rotate the Hearing Level dB dial.
Frequency displayed on the screen reflects the frequency
presented to the patient. To change, rotate the Frequency Hz dial.
5.7 Preparing for Testing
5.7.1 Preparing the Patient
The patient should sit at a distance of at least 1 m from the device.
Prior to hearing threshold level measurements, the following instructions should be given:
"You will now hear a variety of tones with various loudness levels, raise your hand,
or press the response switch, as soon as you hear the tone in either ear“.
5.7.2 Placement of Headphones (for Testing with Headphones)
Eliminate any obstructions which will interfere with the
placement of the ear cushions on the ear (i.e. hair,
eyeglasses).
Ensure that the headphones (Figure 17) are positioned
correctly: red phone on the right ear, blue phone on the left
ear. Adjust the headband of the headphones so that the
earphones are positioned at the correct height (i.e. the
sound output grid exactly facing the ear canal).
5.7.3 Performing Tone Audiometric Tests (Air Conduction Testing)
5.7.3.1 Pretest Set-up and Instructions
Hearing threshold levels can be determined by presenting test signals to the test subject
with the included headphones (air conduction – AC). The purpose of AC audiometry is to
establish the hearing sensitivity at various frequencies. The test can specify the AC loss
but cannot distinguish between conductive versus a sensorineural abnormality.
5.7.3.2 Threshold Determination
A threshold test is seeking the lowest level a tone is heard at least 50% of the time. The
test normally starts at 1000 Hz on the patient's better ear. Select Right/Left (F2 key). A
procedure of “down 10 dB, up 5 dB” is typically utilized to establish a threshold at each
frequency. Vary the length of the tone and intervals between tone presentations to ensure
the patient is responding to the tone not just repeating the behavior.
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