Presented in February, 2002
Pure tone audiogram
Start with the better hearing ear (according to the patient).
Start with 1000Hz.
Next proceed to test 2000, 4000, 8000, 500 and 250Hz.
Present a tone of about 3 seconds in duration at a level of 30dB.
If the patient does not respond, raise the level in 20dB steps until a response is obtained. Patients should be instructed to respond by raising a finger or pressing a button when the hear the tone.
It is important to vary the inter-tone intervals with occasional fairly long intervals to avoide anticipation of the tone.
After an initial response is obtained reduce the levels in 10dB increments until no response occurs and again is raised at 5dB intervals.
Threshold is defined at the lowest level at which a response occurs twice in a series of three ascending trails.
The is known as the '10 down, 5 up' procedure.
Air conduction: o - right x - left