-Hearing is graphed on an audiogram, a graph of the softest sounds you can hear.
-The graph is laid out like a piano keyboard, with low to high frequencies (low to high pitches) going from left to right, and the graph is laid out from soft sounds on the top to loud sounds on the bottom.
[CLICK ON THE IMAGE BELOW TO SEE THE WHOLE IMAGE]
-Normal hearing is classified as being between -10dBHL and 15dBHL, although 0dB from 250Hz to 8kHz is deemed to be 'average' normal hearing.
-For humans the test involves different tones being presented at a specific frequency (pitch) and intensity (loudness)
-When the person hears the sound they raise their hand or press a button so that the tester knows that they have heard it
Audiometry
-is the testing of hearing ability.
-Typically, audiometric tests determine a subject's hearing levels with the help of an audiometer, but may also measure ability to discriminate between different sound intensities, recognize pitch, or distinguish speech from background noise.
-Acoustic reflex and otoacoustic emissions (OAE) [is a sound which is generated from within the inner ear] may also be measured. Results of audiometric tests are used to diagnose hearing loss or diseases of the ear, and often make use of an Audiogram.
Type A. Subjective audiometry
1. Pure tone audiometry - (PTA) is the key hearing test used to identify hearing threshold levels of an individual, enabling determination of the degree, type and configuration of a hearing loss.
2. Speech audiometry
B. Objective audiometry
1. Electronic response audiometry
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