In airway thresholds, thresholds of 1000 Hz, 2000 Hz, 4000 Hz, 8000 Hz, 1000 Hz, 500 Hz and 250 Hz are determined respectively. In some clinics, routine measurements are also made at 6000 Hz. If there is more than 20 dB difference between the two frequencies, the intermediate frequencies can be tested. Tests are performed at 1000Hz, 2000 Hz, 4000 Hz and 500 Hz in bone pathway thresholds. Bone pathway thresholds at frequencies above and below this are not reliable.
Usually, 10 dB decreases are made starting from the high intensity that the patient can hear. 5 dB increments are made from the level that the patient has not heard. The level of severity that the patient begins to hear again is marked as the patient’s hearing threshold. This technique is called Hughson-Westlake technique. (Desscending Method)
There are also Ascending method. In this method, starting from the level of inaudible, 10 dB increments are made. 5 dB drops are made from the level he hears. The least heard level is determined as the hearing threshold.
At a severity level, the patient must press 3 out of 5 signals or 2 out of 3 signals to decide what he hears. (Not much in practice)