Pure-tone audiometry is a vital behavioral test that assesses hearing sensitivity, involving both the peripheral and central auditory systems. It measures pure-tone thresholds (PTTs) to identify the softest sound an individual can hear at least 50% of the time. An audiogram displays the hearing sensitivity graphically, plotting intensity against frequency.

This test plays a crucial role in determining whether an individual’s hearing acuity is normal or impaired. The test measures air conduction hearing thresholds for tonal stimuli in the frequency range of 0.125 kHz to 8 kHz, using headphones. Bone conduction hearing thresholds are measured for tonal stimuli in the frequency range of 0.25 to 4 kHz, using a headband with oscillator.

The hearing threshold values for all tested frequencies are connected to form an audiogram, also known as a pure-tone audiogram or tonal audiogram. The hearing thresholds are measured in dB HL units calibrated on normal-hearing young populations so that the bone conduction curve lies slightly above the air conduction curve. Regular pure-tone audiometry can help detect hearing loss early, enabling timely intervention and treatment for optimal hearing health.

Degrees of hearing loss

• Normal hearing (0–25 dB): At this level, hearing is within normal limits.

•  Pure-tone audiometry should be performed in a soundproof booth (parameters are defined in International Organization for Standardization (ISO) norm (ISO 11957:1996, 1996). Calibration of the test equipment and the stimuli is needed before testing according to ISO standards. A rest period of at least 16 hours after last exposure to noise is advised, in order to avoid TTS influence on the audiometric test result.