Elements Of The Audiogram
The audiogram is a graphic representation of how we hear. It provides information on the degree and type of hearing loss. Hearing loss is not difficult to document. But understanding the audiogram is not always easy.
The audiogram is a graph laid out like a piano keyboard with low to high frequencies graphed from left to right on the horizontal axis.
The vertical axis charts loudness of sound in decibels–starting with soft sounds at the top and loud sounds on the bottom. Results of both ears appear on the audiogram with “X” representing the right ear and “O” representing the left ear.
The speech banana is an informal term referring to the frequency and decibel range covered by normal human speech. When it is mapped out on an audiogram with frequencies on horizontal axis and decibel levels on the vertical axis, the shape of the normal speech range takes the shape of a banana.
When people are given hearing tests, the person administering the test pays special attention to hearing loss that falls within the speech banana. People with good hearing will have results that are located above the speech banana, meaning that they can hear sounds at both lower and higher frequencies than normal human speech, and lower decibel levels than normal human speech. If hearing test results fall below or within the speech banana, it means that the person may have difficulty hearing normal human speech.
It is common for individuals to permanently lose their hearing in only a portion of the pitch range. That is, many people first lose their ability to hear high-frequency sounds like ‘s,’ ‘sh,’ and ‘ch’ or the voices of children or women with higher-pitched voices. In many cases, speech is “heard” but misunderstood. When a portion of the speech spectrum is missing, it sounds like mumbling.