**5.1 Pure tone audiometry**

It is the most commonly used method of measuring hearing acuity. It is a subjective test. The frequencies usually tested are at octave steps i.e., 125, 250, 500, 1000, 2000, 4000, 8000 Hz. A pure tone audiometer is an electronic instrument capable of producing pure tone sound of different frequencies at variable intensities. It helps in qualitative and quantitative diagnosis of hearing loss.
