One of the first indications of hearing impairment is reduced ability to understand speech in background noise. The measurement of speech intelligibility is called speech audiometry. Speech audiometry is used for various purposes, such as diagnosing hearing loss or comparing the effect of different hearing aids.
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One of the first indications of hearing impairment is reduced ability to understand speech in background noise. The measurement of speech intelligibility is called speech audiometry.
In speech audiometry, a number of words or sentences (speech signal) are presented to the test subject through headphones or loudspeakers.
The threshold for speech recognition is called the Speech Reception Threshold (SRT). The SRT is determined by varying the speech signal volume level until a specified percentage of the speech signals, usually fixed at 50%, can be repeated correctly.
As mentioned, the speech signals are usually presented at different volume levels, including the most comfortable level (MCL), and usually also together with noise signals. This is done to determine the test subject’s ability to differentiate among speech sounds at normal volume levels, also referred to as speech discrimination or discrimination loss.
The following technical terms are related to speech intelligibility measurements: |
 Speech reception threshold (SRT) is the volume at which the test subject can repeat a certain percentage, for example 50%, of the words presented. |
| Speech discrimination indicates how many of the words are recognised correctly when presented at a comfortable volume. 100% speech discrimination = perfect recognition. |
| Discrimination loss indicates how many of the words are not recognised correctly when presented at a comfortable volume. 0% discrimination loss = perfect hearing ability. |
The hearing healthcare professional presents speech which the test subject repeats, for example mono- or two-syllable words, numbers or brief sentences. This is done at varying volume levels until the person’s ability to differentiate among speech sounds has been determined.
The speech signals are presented through headphones or loudspeakers.
SEE ALSO:
Hearing testHearing thresholdDynamic range
