Lab (2)- A
(Pure Tone Audiometry – Air Conduction)
Aims:
1. To become familiar with performing air conduction audiometry
2. At the end of this practicum, the student should be able to:
a) Place earphones on the client properly
b) Instruct the client properly
c) Adjust audiometer for air conduction test without masking
d) Establish air conduction thresholds across all tested frequencies for both ears
e) Label hearing thresholds on the audiogram using correct symbols
f) Calculate and record pure tone average for both ears
g) Fill in the rest of the required information on the data sheet
Requirements:
Each student should establish her partner's air conduction thresholds for both ears and submit one audiogram sheet.
Deadline for submitting this lab: Tuesday 14/4/2015
Operating instructions for Air Conduction Testing
Preparation
1. Switch power on. If the audiometer is a battery powered model check that the battery indicator shows sufficient battery strength
2. Set frequency dial to 1000 Hz.
3. Turn attenuator to required setting – usually 30 dB Hl or higher (if necessary) is chosen for the initial assessment.
4. Set output switch to right or left ear depending on which ear is tested first. By convention, the right ear is always tested first, unless it is known to have a greater hearing loss than the left.
5. Set masking attenuator to the off position.
Testing
1. Instruct client that sounds will be presented and that a response must be made every time a tone is heard. Demonstrate the required response (for example, pressing a button or raising a finger). Emphasize that this response is to be made even when the sound is very faint. Explain that only one ear will be tested a time and state, which ear, will be tested first.
2. Place the headset on the client. Remember that the red earphone for right ear and the blue earphone for the left ear, ensure that:
a) The earphone is level with the entrance of the ear canal
b) The earphone cushion seals well
c) The headset stays in place securely but comfortably
3. Present a sound stimulus at 1000 Hz at the initial presentation level. Chose your tested ear (i.e. Right ear). If no response occurs, increase the attenuator setting in 10 dB increments until a response occurs. The stimulus should be between 1 and 1.5 sec.
4. When a response is recorded, reduce the attenuator dial setting by 10 dB and present the tone. If a response is recorded repeat step 4 until no response is recorded.
5. Increase attenuator dial setting by 5 dB until a response occurs.
6. Repeat step 4.
7. Repeat step 5.
8. The attenuator dial setting at which the client responds at least 2 out of 3 presentations when in the ascending mode is regarded as the threshold for that client for that frequency.
9. Record this threshold on the audiogram form.
10. Change the frequency selector setting to 2000 Hz and follow the same procedure to establish threshold.
11. Repeat for all other frequencies to be tested. Usually 1 kHz, 2 kHz, 4 kHz, 8 kHz. Then retest 1 kHz (for the first ear tested only). Then test 500 Hz and 250 Hz.
12. Test the other ear (i.e. Left ear) by changing the output switch and repeating the proc