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How is a pure-tone audiogram created?

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A pure-tone audiogram is created through a clinical procedure known as pure-tone audiometry, which measures an individual's hearing threshold across various frequencies.1

The Testing Process

Setup: The patient is placed in a quiet, sound-treated environment and wears an earphone or sits before a loudspeaker. Each ear is tested separately, with the nontest ear often shielded by masking noise to prevent cross-hearing.12
Methodology: Using an audiometer, the audiologist presents single-frequency tones (typically ranging from 500 Hz to 8,000 Hz) at discrete intervals. The intensity is adjusted using an attenuator.12
Threshold Determination: Following the "method of limits," signals are presented in ascending or descending runs. The hearing threshold is defined as the lowest intensity level at which the listener detects the tone at least 50 percent of the time.12

Plotting the Audiogram

The results are recorded on a chart called an audiogram:
* Axes: The vertical axis (ordinate) represents the hearing level in decibels (dB), while the horizontal axis (abscissa) represents the signal frequency.1
* Reference: The 0 dB line, or "audiometric zero," represents the median hearing threshold of healthy young adults.12