An audiogram is a chart a hearing test is marked on. The degree of hearing loss is measured in dB for defined key frequencies. The frequency is measured in Hertz, abbreviated with “Hz”. Curves displayed in Decibels (dB) generally describe the individual hearing threshold of a person compared to the normal hearing average, which lies around 0 dB. Due to individual differences, all thresholds up to 20 dB HL are considered normal.
Symbols are placed on the audiogram that show the person’s air conduction and bone conduction thresholds for each of the key frequencies. The audiogram shows the softest level at which a sound is perceived. This is also referred to as the hearing threshold. Different symbols are used to distinguish between air- and bone conduction measurements, as well as which ear the measurement refers to.
To read and understand an audiogram, you have to have to a look at the loudness level and frequencies of different speech sounds presented in the audiograms below. Because of the shape of this speech area, it is also referred to as a “speech-banana”. Vowels are low frequency sounds with a higher volume than consonants, which are soft high frequency sounds. The vowels carry the loudness impression of speech whereas the consonants carry the meaning, e.g. house or mouse.